document_title: Arrow (season 1)

question_text: when does felicity find out oliver is the green arrow

text: Arrow (season 1)

text: Cast and characters[edit]

text: Main[edit]

text:
Stephen Amell as Oliver Queen / The Hood
Katie Cassidy as Laurel Lance
Colin Donnell as Tommy Merlyn
David Ramsey as John Diggle
Willa Holland as Thea Queen
Susanna Thompson as Moira Queen
Paul Blackthorne as Quentin Lance

text: Recurring[edit]

text:
Jamey Sheridan as Robert Queen
Kelly Hu as Chien Na Wei / China White
Emily Bett Rickards as Felicity Smoak[a]
John Barrowman as Malcolm Merlyn / Dark Archer
Jessica De Gouw as Helena Bertinelli / Huntress
Colin Salmon as Walter Steele
Annie Ilonzeh as Joanna De La Vega
Roger Cross as Lucas Hilton
Byron Mann as Yao Fei
Janina Gavankar as McKenna Hall
Manu Bennett as Slade Wilson
Christie Laing as Carly Diggle[b]
Colton Haynes as Roy Harper
Alex Kingston as Dinah Lance
Jeffrey Nordling as Frank Bertinelli
Sebastian Dunn as Edward Fyers
Celina Jade as Shado
Chin Han as Frank Chen
Adrian Holmes as Frank Pike
Jarod Joseph as Alan Durand

text: Guest[edit]

text:
Michael Rowe as Floyd Lawton / Deadshot[c]
Kyle Schmid as Kyle Reston / Ace
Tahmoh Penikett as Nick Salvati
Brian Markinson as Adam Hunt
Jacqueline MacInnes Wood as Sara Lance
Emma Bell as Emily Nocenti
Andrew Dunbar as Garfield Lynns / Firefly
Ben Browder as Ted Gaynor
Seth Gabel as The Count
Chelah Horsdal as Kate Spencer
Currie Graham as Derek Reston / King
Sarah-Jane Redmond as Mrs. Reston / Queen
David Anders as Cyrus Vanch
John Cassini as Russo
James Callis as Winnick Norton / Dodger
Danny Nucci as Raynes
Ona Grauer as Vivian
Audrey Marie Anderson as Lyla Michaels
J. August Richards as Mr. Blank

text: Episodes[edit]

text:
No.overallNo. inseasonTitleDirected byWritten byOriginal air dateProd.codeU.S. viewers(millions)11"Pilot"David NutterStory by : Greg Berlanti & Marc Guggenheim Teleplay by : Andrew Kreisberg & Marc GuggenheimOctober 10, 2012 (2012-10-10)2968184.14[2]
Billionaire playboy Oliver Queen, missing and presumed dead after a shipwreck that claimed the life of his father, Robert, is discovered alive after five years on a remote Pacific island. He is welcomed home to Starling City by his mother Moira, stepfather Walter Steele, younger sister Thea, and best friend Tommy Merlyn, but they sense he has changed. Moira assigns John Diggle as Oliver's bodyguard. Oliver hides the truth about the man he has become, and tries to reconcile with his former girlfriend, Laurel, whom he cheated on with her sister Sara (who died in the shipwreck). While reconnecting with those closest to him, by night Oliver secretly masquerades as a hooded vigilante archer, attempting to fulfill his dying father's entreaty: to right the wrongs of his family. Oliver's first goal is to take down corrupt millionaire Adam Hunt, who has scammed millions from various people in the city. Laurel's father, police detective Quentin Lance, becomes determined to arrest the vigilante. Meanwhile, it is revealed Oliver's mother has an agenda at odds with her son, having orchestrated a kidnapping to determine what Robert told him after the shipwreck.
22"Honor Thy Father"David BarrettStory by : Greg Berlanti & Marc Guggenheim Teleplay by : Andrew Kreisberg & Marc GuggenheimOctober 17, 2012 (2012-10-17)2J73023.55[3]
Laurel brings a civil suit against millionaire Martin Somers, who is also one of Oliver's targets, for taking part in drug trades with the Chinese Triad that ultimately led to the death of a young woman's father. As the vigilante, Oliver threatens Somers to make him confess to the murder as penance for all of the wrongs he has done to the city. Instead, Somers contacts the Triad, who send the assassin Chien Na Wei to kill Laurel. Oliver saves Laurel from Chien; he later obtains Somers' confession and gives an audio recording of it to Quentin. Meanwhile, Moira and Walter push Oliver to take a position at the company. Oliver stymies their efforts by using the opening of the company's new applied sciences division to publicly opt out of the position, knowing that he cannot simultaneously honor Robert's request to fight for the city and be the man Moira wants him to be. She is revealed to be conspiring with a man affiliated with a symbol that exists in Robert's book possessed by Oliver. A flashback to Oliver's time on the island shows him being attacked by an unknown hooded figure wielding a bow and arrow.
33"Lone Gunmen"Guy BeeStory by : Greg Berlanti & Andrew Kreisberg Teleplay by : Marc Guggenheim & Andrew KreisbergOctober 24, 2012 (2012-10-24)2J73033.51[4]
Oliver tracks down another millionaire from his list, before the latter is killed by an assassin known as Deadshot. Oliver decides to build a new dance club above his hideout as a cover for his nighttime disappearances. While comparing the competition, he finds Thea, who reveals that Laurel and Merlyn had been involved during Oliver's absence. Laurel becomes suspicious when Oliver does not react to it, and concludes he already knew. She and Merlyn start dating again. Meanwhile, Oliver uses the assassin's M.O. to learn his true identity, Floyd Lawton, and his assignment to kill businessmen including Walter at an auction. As the vigilante, he enlists the help of Quentin to prevent Lawton's plan. Oliver succeeds, apparently killing Lawton in the process, but Diggle is shot during the fight. In order to save Diggle's life, Oliver is forced to reveal his dual identity to him. Flashbacks reveal that the Asian archer who attacked Oliver was actually trying to help him; Oliver misunderstands and escapes; and is revealed to be pursued by an unknown group of armed men.
44"An Innocent Man"Vince MisianoMoira Kirland & Lana ChoOctober 31, 2012 (2012-10-31)2J73043.05[5]
Oliver offers Diggle a chance to fight at his side and help the city, which the latter refuses. Later, Oliver discovers a connection between Peter Declan, a death row inmate, and Jason Brodeur, one of the men on his list. As the vigilante, he enlists the help of Laurel to prove Declan's innocence. Working together, the pair uncovers the truth, but Brodeur has his mercenaries stage a prison riot so that they can have Laurel and Declan killed before the truth is revealed. Oliver sneaks into the prison dressed as a guard and saves the two, with her realizing that the vigilante is merciless. Declan is exonerated while Brodeur is arrested. Diggle meets with Oliver and agrees to work with him so that he can both protect the city and protect Oliver from losing his humanity. Quentin arrests Oliver on suspicion of being the vigilante. Meanwhile, Walter discovers that Moira has been keeping the salvaged and sabotaged family yacht hidden in a warehouse. Flashbacks show that the archer forced Oliver to kill a bird for food, making it the latter's first kill. He was also taught to forget Laurel.
55"Damaged"Michael SchultzWendy Mericle & Ben SokolowskiNovember 7, 2012 (2012-11-07)2J73053.75[6]
Oliver hires Laurel as his attorney and his bail is accepted. Given Oliver's time on the island, the District Attorney offers an insanity plea with indefinite treatment for post-traumatic stress disorder in a psychiatric facility. Oliver declines, instead offering to take a polygraph test to prove his innocence, which he passes. While remanded under house arrest, Oliver throws a prison-themed party, maintaining his bachelor playboy facade. He has Diggle pose as the vigilante and stop a German arms dealer who is in the city to sell automatic weapons to the city's gangs. The plan works and the charges are dropped after Quentin kills a man who was sent by Moira's co-conspirator to kill Oliver. However, Laurel begins to suspect Oliver. Moira threatens her associate to stay away from her family. Walter leaves the house after confronting Moira on her lies. Flashbacks show Oliver caught and tortured by the armed men, led by Edward Fyers, for the location of the archer, who is revealed to be a former military officer, before being saved by the latter.
66"Legacies"John BehringMoira Kirland & Marc GuggenheimNovember 14, 2012 (2012-11-14)2J73063.83[7]
Oliver begins preparing to attack another individual from the list, but Diggle argues that he should expand his work and help the police stop a group of bank robbers. Oliver initially refuses, believing that it detracts from his mission to right Robert's wrongs, but agrees finally. The former deduces that the robbers are actually a family unit, and that the leader Derek Reston worked for Queen Industries before Robert outsourced 1500 jobs to China and the Reston family lost their home as a result. Feeling guilty, Oliver tries to persuade Derek to right his own wrongs, but learns that the family are going to rob another bank. During Oliver's confrontation, Derek is fatally shot. Meanwhile, Merlyn throws Laurel a fundraiser to support her law firm, CNRI, hoping to prove his love for her that way. Oliver and Moira manage to regain their emotional connection. Flashbacks show Oliver having a dream of Robert blaming him for his idleness and reveal how Oliver first discovered the target names in his father's notebook.
77"Muse of Fire"David GrossmanStory by : Andrew Kreisberg Teleplay by : Geoff Johns & Marc GuggenheimNovember 28, 2012 (2012-11-28)2J73073.74[8]
Moira is almost shot by a mysterious assailant who was attempting to assassinate an associate of mob boss Frank Bertinelli. Oliver attempts to infiltrate Frank's business to discover the identity of the attacker. Frank blames Chien and the Triad gang for the murders of his people. Oliver learns that the attacker is Helena Bertinelli, Frank's daughter, with whom the former had just been on a date. Helena reveals that she is looking for revenge against her father, who she blames for the murder of her fiancé, who according to Frank was gathering evidence against him to give FBI. Helena and Oliver are abducted by Frank's right-hand man, Nick Salvati, in connection to the deaths; she reveals that she was the one gathering evidence and kills Salvati after learning he was the one who killed her fiancé. She also deduces Oliver's identity as the vigilante after witnessing him fight Frank's henchmen. In the end, Helena and Oliver share a kiss. Meanwhile, Tommy is cut off financially by his father, Malcolm, who is revealed to be Moira's co-conspirator. Laurel sticks with him, stating that she does not want him for money. Walter returns home.
88"Vendetta"Ken FinkBeth Schwartz & Andrew KreisbergDecember 5, 2012 (2012-12-05)2J73083.35[9]
Oliver decides to teach Helena that there is justice outside of revenge after witnessing her try to kill the head of the Triad. Diggle expresses his disapproval, but to no avail. She dresses as a purple vigilante and the duo has another man from the list arrested. Helena starts to buy into the idea, but leaves him after finding out that Laurel was his former girlfriend and believing that they are still together. Helena goes after the Triad, killing their leader. As a result, Chien and her men go after Frank, believing him to be responsible, but Oliver gets there in time to stop them. Oliver also stops Helena from killing Frank, who is arrested; and she threatens to reveal his identity if he tries to come after her in the future. Meanwhile, Tommy finally tells Oliver about Malcolm's action and asks for a job at the club that Oliver is attempting to build, which is accepted. Using Felicity Smoak's help, Walter learns more about the secret organization that Moira is a part of, finding a notebook containing the list.
99"Year's End"John DahlStory by : Greg Berlanti & Marc Guggenheim Teleplay by : Andrew Kreisberg & Marc GuggenheimDecember 12, 2012 (2012-12-12)2J73093.11[10]
Hunt is killed by a mysterious archer. Quentin deduces that a copycat is at work, but his superior publicly blames the hooded vigilante. Oliver plans a Christmas party at the mansion to bring back the spirit of the holidays to his family. He saves some hostages from the archer, and the two archers are injured after fighting, with Oliver realizing that Robert wasn't the author of the list. The archer escapes and is revealed to be Malcolm. Walter finds out about the vigilante's objective and is kidnapped by one of Malcolm's associates. The organization's plan is revealed to be starting six months later, when thousands of people will die for what it believes to be for the greater good. Flashbacks show the Chinese archer, Yao Fei, capturing Fyers, who tells Oliver that the island was a prison for dangerous criminals and that his unit was tasked to exterminate the inmates, including Yao, after the program was shut down. Yao is captured by the unit while leading Oliver to a possible escape from the island; and the latter escapes.
1010"Burned"Eagle EgilssonMoira Kirland & Ben SokolowskiJanuary 16, 2013 (2013-01-16)2J73103.06[11]
Six weeks after his fight with Malcolm, Oliver avoids any activities as his vigilante, despite insistence from Diggle. When a firefighter is killed in the line of duty, Laurel suspects that he was murdered and steals the phone the vigilante gave Quentin in order to contact him for help. Tracking down the suspect, Oliver is overpowered during the confrontation, but discovers that the murderer is a former firefighter. Oliver learns that the murderer is Garfield Lynns, a firefighter thought to have died in a massive fire several years prior, but survived with severe burns. Lynns shows up at a fundraiser held for support of the victims in order to kill the fire chief. As the vigilante, Oliver saves the chief before Lynns commits suicide. The media calls the vigilante a hero while Oliver decides to continue his hunt of the list members. Moira decides to take over for Walter as C.E.O. Quentin plants a listening device on the phone to monitor Laurel's communications with the vigilante. Flashbacks show Oliver killing a mercenary, wearing his uniform and recovering his tools, including a map.
1111"Trust But Verify"Nick CopusGabrielle StantonJanuary 23, 2013 (2013-01-23)2J73113.14[12]
After an armored truck is robbed, Oliver believes that one of the thieves is former Marine Ted Gaynor, from his target list. Diggle dismisses Oliver's assumption, as Gaynor was Diggle's commanding officer during his time in Afghanistan. Oliver finds Gaynor and steals encrypted data, as Diggle prevents the former from getting any information directly from Gaynor. The data is revealed to be plans for robbing armored trucks, which Oliver uses to track the thieves. Diggle learns that Gaynor was the mastermind behind the robberies, and is forced to join Gaynor's team, but backs out of helping them at last. Oliver arrives in time and kills Gaynor. Meanwhile, Thea tells Oliver her belief that Moira and Malcolm are involved as the former believes they were before Robert's death. Oliver asks Moira, who states Robert was the unfaithful. Tommy refuses Malcolm's request to sign the paper of selling the clinic established by the former's mother, who died when he was 8 and Malcolm left him for years subsequently. Thea is arrested by the police after having a crash as a result of drug use. Flashbacks show Oliver being captured by the mercenaries as Yao was apparently working for them.
1212"Vertigo"Wendey StanzlerWendy Mericle & Ben SokolowskiJanuary 30, 2013 (2013-01-30)2J73122.97[13]
The judge dismisses the plea bargain of Thea and orders the charges brought to trial. Helping Thea, Oliver begins working on tracking down the supplier of the drug, which is known as Vertigo; he discovers that the supplier is called "The Count", and arranges a meeting through his contacts with the Solntsevskaya Bratva. The meeting is broken up by the police, and the Count injects Oliver with a dose of Vertigo. While showing the effects of overdose, the latter still continues his investigation. He uses the ingredients to track the location of the Count. As the vigilante, Oliver is able to confront the Count and inject him with Vertigo, causing irreparable damage. Laurel persuades Quentin to get Thea community service and two years of probation, which she begins serving at Laurel's legal office. Felicity shows Oliver the list of names that Steele discovered, and informs him that they came from Moira. Flashbacks show Yao overpowering Oliver in a mandatory duel and making him appear dead. His body is thrown to a waterfall, where he wakes up and finds an upgraded map, planted by Yao.
1313"Betrayal"Guy BeeLana Cho & Beth SchwartzFebruary 6, 2013 (2013-02-06)2J73132.96[14]
Moira denies knowledge about the list. Diggle decides to investigate her daily activities. Laurel enlists the help of the vigilante when criminal Cyrus Vanch is released from prison. Using the microphone inside the phone, Quentin and his team intercept the vigilante, who manages to escape. Vanch kidnaps Laurel. Quentin and the vigilante team up to save Laurel, as the former realizes that Vanch has contacts on the police force and that was how he learned of her. The duo saves Laurel. She demands Quentin to stay away from her for betraying her trust. In order to protect her, Oliver decides to cut his contact with her as the vigilante. Diggle presents evidence to Oliver that his mother is connected to the group he is hunting, and that she also knew of Robert's yacht. Oliver decides to interrogate his mother as the vigilante. In flashbacks, Oliver meets Slade Wilson, an Australian Intelligence operative who came to the island to free Yao Fei. It is revealed that the masked mercenary who tortured Oliver was Wilson's partner; and Wilson has the same mask. He starts training Oliver to get him ready to infiltrate the airfield, the only apparent way out.
1414"The Odyssey"John BehringStory by : Greg Berlanti & Andrew Kreisberg Teleplay by : Andrew Kreisberg & Marc GuggenheimFebruary 13, 2013 (2013-02-13)2J73143.29[15]
Oliver is critically shot by Moira and escapes. He exposes his secret to Felicity, and asks her to take him to his hideout. With Diggle's help, the bullet is removed and Oliver is stabilized. Felicity refuses to join Oliver's fight, but decides to help them find Steele. Oliver convinces Diggle to stop investigating Moira until they find out more about the organization. Flashbacks show Oliver being trained. Wilson reveals that his former partner is Billy Wintergreen, who was sent with Wilson to find out Fyers' mission. Their plane was shot down and they were captured by Fyers' men. Wintergreen accepted Fyers' offer to change sides. After infiltrating the airstrip, Wilson reveals plans to send in an airstrike to wipe out all of Fyers' operation. Oliver heads out to save Yao, but is recaptured by Fyers. Before he can be executed, Wilson arrives, rescuing Oliver and killing Wintergreen. Although they miss the supply aircraft, Wilson and Oliver decide to continue to work together to get off the island, with the former stating that Fyers is hired by another party for a purpose. Yao is revealed to have changed sides because his daughter, Shado, is held captive by Fyers.
1515"Dodger"Eagle EgilssonBeth SchwartzFebruary 20, 2013 (2013-02-20)2J73153.15[16]
Oliver learns of a jewel thief named "Dodger", who uses hostages tagged with bomb collars. Felicity suggests that Oliver bug the phone of Detective McKenna Hall, an old friend of Oliver's, to gain information on the Dodger. She also convinces Oliver to ask Hall out on a date so that he can have some down time. Through the wire tap, Oliver is able to determine the Dodger's next location, but is stunned by a bomb thrown by the thief, who gets away. To draw out the Dodger, Oliver donates antique jewels to an auction. It works; but when Felicity confronts the thief, he places a collar on her to ensure his getaway. Oliver manages to stop the Dodger and deactivate the collar. Diggle starts dating his former sister-in-law. Thea has a run-in with a thief named Roy Harper, and Moira attempts to make a deal with Chien to have Malcolm killed, so that she can leave the secret organization, whose plan is called the "Undertaking". Flashbacks show Oliver trying to treat Wilson's infected wound by finding the herbs Yao used; and is intercepted by a wounded man who asks for help; but Oliver leaves him as the former believes it to be a trap.
1616"Dead to Rights"Glen WinterGeoff JohnsFebruary 27, 2013 (2013-02-27)2J73163.17[17]
Oliver kills a hired gunman, and realizes that the latter's target is not safe yet. Chien hires Lawton, who is revealed to have survived Oliver's attack, to take out Malcolm after the previous gunman's death. Malcolm asks Tommy to attend an award ceremony where Malcolm will be receiving a humanitarian award; Tommy is persuaded by Oliver to attend. At the last moment, Oliver discovers that Malcolm is the target and races to the event to save him. Although he is almost caught by Hall, Oliver manages to get Malcolm away from Chien's men. Malcolm is shot with one of Lawton's poisonous bullets, and Oliver is forced to reveal his identity to Tommy so that he can save Malcolm's life. Malcolm and Tommy reconcile. The former tells Moira about his belief that someone from the organization attempted to kill him. Laurel is confronted by her mother, Dinah, who states that Sara, the former's sister, might be alive. During a flashback, Oliver is shown repairing a damaged radio, which Wilson uses to tune into the radio communications of Fyers. They find out that Fyers possesses an advanced anti-aircraft missile launcher.
1717"The Huntress Returns"Guy BeeJake Coburn & Lana ChoMarch 20, 2013 (2013-03-20)2J73173.02[18]
Helena returns to Starling City to kill Frank after she learns that he plans to make a deal with the F.B.I. for witness protection. Oliver opens his nightclub and refuses her request for help; and she attacks Tommy to force his assistance. Helena is captured by the police's trap. Oliver breaks her out to protect his secret and demands that she leave Starling City. Instead, she forces Felicity to find Frank's location. Oliver manages to stop Helena from killing Frank, but when Hall arrives, Helena shoots her and escapes. In the hospital, Hall breaks up with Oliver, heading to Helena's tarnish on Oliver's character. Meanwhile, Tommy's knowledge of Oliver's secret affects his relationship with Laurel; but the former reconciles with Oliver. Dinah presents her evidence of Sara's existence to Quentin and Laurel. Thea and Roy get closer. In a flashback to the island, Oliver and Wilson steal the circuit board of the anti-aircraft missile launcher, which the latter states can start a war, and offer Fyers a trade of the board with a way out of the island.
1818"Salvation"Nick CopusDrew Z. Greenberg & Wendy MericleMarch 27, 2013 (2013-03-27)2J73182.65[19]
Another vigilante appears in Starling City and kidnaps one of Oliver's targets, a slumlord who had charges dropped against him because he was able to pay off the District Attorney. The new vigilante, who is identified as Joseph Falk,  kills the slumlord over a live broadcast. The former kills several prosecutors the same way before going after Harper. Diggle finds out that Falk is using an abandoned subway car, and Oliver is able to catch the car and kill Falk. Oliver realizes the secret organization's plans involve The Glades, a neighborhood filled with crime. Laurel proves to Dinah and Quentin that Sara is not alive. It is revealed that Dinah knew of Sara's plan to escape with Oliver. Malcolm contacts the Triad to find the traitors. Moira turns over her co-conspirator, Frank Chen, to Malcolm, who kills Chen, believing her to be innocent. Flashbacks to the island show Oliver and Wilson freeing Shado, but at the cost of Fyers reacquiring the board. She claims to know Fyers' scheme.
1919"Unfinished Business"Michael OfferBryan Q. Miller & Lindsey AllenApril 3, 2013 (2013-04-03)2J73192.92[20]
When a girl dies after using a new form of Vertigo, Oliver sets out to interrogate the Count and determines the latter has lost his mind from the Vertigo overdose. When news reports state that the Count escaped the asylum, Oliver suspects that the Count was faking his mental illness. Meanwhile, Quentin finds loose connections between Tommy and Vertigo, and attempts to uncover the truth, which almost leads him to discovering Oliver's hideout. Oliver realizes that the Count's psychiatrist is behind the re-emergence of Vertigo. Oliver kills the doctor, and opts not to kill the Count, who has truly lost his mind and was the scapegoat of the doctor's actions. Tommy quits the club after realizing that Oliver suspected him with the drug dealing. Malcolm gives him a job. Oliver decides to help Diggle find Lawton, who killed Diggle's brother. In a flashback, Shado reveals that Yao Fei took the blame of a massacre committed by the Chinese government and was exiled to the island. Now Fyers is using him as a scapegoat for his schemes. She begins training Oliver to use a bow.
2020"Home Invasion"Ken FinkBen Sokolowski & Beth SchwartzApril 24, 2013 (2013-04-24)2J73203.10[21]
Laurel represents the Moore family who are suing a corrupt businessman, who puts a hit on the family, and the couple's young child is the sole survivor. Laurel takes the boy into her custody and is saved by the vigilante from the hitman's attempt. Tommy suggests that they go to Oliver's for protection. An operation headed up by A.R.G.U.S, a government organization, is set to capture Lawton, but Oliver chooses the Moores case. As a result, Lawton escapes and Diggle decides to leave Oliver, who forces the businessman to confess his crimes, leading to the latter's arrest. After killing the latter, the hitman comes to the Queen residence to kill all remaining witnesses, but Oliver manages to kill him. Tommy decides to leave Laurel, believing that he could never compete with Oliver should she discover that he is the vigilante. Elsewhere, Roy starts searching for the vigilante; and Thea agrees to help. During a flashback to the island, Shado continues teaching Oliver to use a bow before Yao Fei brings Fyers' men to their hideout.
2121"The Undertaking"Michael ShultzJake Coburn & Lana ChoMay 1, 2013 (2013-05-01)2J73212.89[22]
Oliver tracks down an accountant of the secret organization and steals his laptop. While decrypting it, Felicity uncovers a link to Walter—a money transfer was made to Dominic Alonzo, an underground casino owner who was hired to kidnap Walter. The pair infiltrate the casino; and Alonzo claims that Walter was killed. Oliver informs his family and Moira confronts Malcolm, who proves to her that Walter is still alive. Oliver, who was listening in, discovers that Malcolm is heading the secret organization, and uses Felicity to ascertain Walter's location. As the vigilante, Oliver frees Walter. Meanwhile, Laurel asks Tommy for the truth about why he left, and Tommy states that Oliver still loves her, a claim he confirms. He asks Diggle to help him stop the "Undertaking". In a flashback, Robert is shown disagreeing with Malcolm's proposed "Undertaking", which would involve leveling the Glades with a machine, which will be built in five years, and killing thousands of people in order to rebuild the area. As a result, Malcolm has a bomb planted on the Queens' yacht just before Robert boards it to head to China for his plan to stop the former.
2222"Darkness on the Edge of Town"John BehringDrew Z. Greenberg & Wendy MericleMay 8, 2013 (2013-05-08)2J73222.62[23]
Malcolm kills the scientists who worked on the device. Diggle dresses as the vigilante and kidnaps Oliver and Moira in an attempt to uncover the truth. The plan works and Oliver's team breaks into Malcolm's company for information. Quentin finally approves Laurel's feelings for Oliver, who realizes that he could cease being the vigilante if he stops the Undertaking. Thus, Oliver reconciles his romance with Laurel and the two make love, which is witnessed by Tommy. Malcolm has the device moved. The vigilante attempts to kill him, who reveals that he is the other archer; the two fight until Malcolm gets the upper hand, discovering Oliver's secret. Meanwhile, Walter files for divorce, revealing to know Moira's involvement in his kidnapping. Roy reveals to Thea that he wants to find the vigilante so that the latter can train the former, pushing her away from himself. In a flashback, the man Oliver chose not to help previously is revealed to be working for Fyers, who reveals that he plans to cripple the Chinese economy by blowing up commercial planes going into the country. His employer is revealed to be a woman. He murders Yao Fei after forcing him to take credit for the attacks via video recording.
2323"Sacrifice"David BarrettStory by : Greg Berlanti Teleplay by : Marc Guggenheim & Andrew KreisbergMay 15, 2013 (2013-05-15)2J73232.77[24]
Malcolm imprisons Oliver; but later manages to escape. He confronts Moira about the Undertaking, which prompts her to hold a press conference and reveal to the city her involvement with Malcolm and the plan to destroy the Glades. She is arrested while Malcolm confirms her claims to Tommy and reveals that he is the other. Quentin, with help from Felicity, is able to dismantle the device. Diggle and Oliver go after and mortally wound Malcolm, who reveals that there is a second device shortly before he dies. The device activates and begins to level the east side of the Glades. Thea goes into the Glades to save Roy, who decides to stay and help others. Laurel is trapped in her office; but Tommy arrives and helps her escape before being trapped himself. Oliver arrives too late, as Tommy had already been mortally wounded by debris. The two tearfully make amends with each other before Tommy dies, leaving Oliver grief stricken. In a flashback, Fyers fires a missile at an approaching airliner, but Oliver and Shado manage to override the coordinates and destroy the missile. Afterward, Oliver kills Fyers, revealed to have gained relative skill with bow.

text: Production[edit]

text: On January 12, 2012, The CW was preparing a new series centered around the character Green Arrow, developed by Andrew Kreisberg, Greg Berlanti and Marc Guggenheim.[25] A week later, the series, now known as Arrow, was ordered to pilot, which was directed by David Nutter, who also directed the pilot for Smallville, a series following Clark Kent on his journey to become Superman.[26] At the end of the month, Stephen Amell was cast in the titular role of Oliver Queen.[27] When developing the series, producer Marc Guggenheim expressed that the creative team wanted to "chart [their] own course, [their] own destiny", and avoid any direct connections to Smallville, which featured its own Green Arrow/Oliver Queen (Justin Hartley), opting to cast a new actor in the role of Oliver Queen.[28] Unlike with Smallville, the series does not initially feature super-powered heroes and villains. Instead, the creative still took inspiration from Smallville, as one of the main themes of Arrow was to "look at the humanity" of Oliver Queen, as Smallville had done with Clark Kent. The decision not to include superpowers was, in part, based on the executives' desire to take a realistic look at the characters in this universe.[29] The series was given a full season pick up on October 22, 2012.[1]

text:
"I think the idea is to—not all the time, and not with a set regularity—but I think it is critical to explore how he went from the person that he was when he left the island—which is extremely different: he's spoiled, he's entitled, he's a bit of a jerk—and he comes off it something very, very different. So we're going to explore how he gets there."[29]
—Stephen Amell on the use of flashback storytelling.

text: The series develops relationship triangles: some love triangles, others designed to catch characters in "philosophical debates".[30] Kreisberg provides one such example: "Every week, Oliver will be facing a bad guy, but the truth is, his real nemesis is Detective Lance, who's trying to bring him into justice.[...] His daughter is going to be caught in the middle, because she loves and respects her father, and she's always believed in what he believed, but at the same time, she's going to see this dark urban legend out there that's actually doing a lot of good; the kind of good that she wants to be doing in her role as a legal aid attorney."[30] Learning from previous experiences working in television, the producers worked early on identifying the major story arcs for the series, specifically the first season, including "mapping out" how to accomplish them. Taking inspiration from Christopher Nolan's Batman film series, the creative team decided to "put it all out there" and "not hold back" from episode to episode.[30]

text: The team strives to include various DC Comics characters and aspects of the DC universe. Guggenheim cited Big Belly Burger, a restaurant franchise introduced in the Superman comics, which appears in Arrow's third episode and onward. Kreisberg said, "There are so many characters in the DC Universe who haven't gotten their due in TV and film. We're so excited to reach into [the DC comics] roster and take some of these lesser-known characters that are beloved by fans, and do our spin on the characters."[31]

text: Casting[edit]

text:
On January 31, 2012 Stephen Amell became the first actor to be cast, having previously appeared on other CW dramas such as The Vampire Diaries and 90210.[32] Fan reaction to Amell's castin was mixed, with many fans wanting Justin Hartley to reprise his role from Smallville.[33] Amell was one of the first actors to audition for the role of Oliver Queen, and Kreisberg felt that he "hit the target from the outset" and "everyone else just paled in comparison".[28] Arrow's pilot script was the first Amell auditioned for during pilot season, having received multiple scripts at the start of the year.[34]
Producer Marc Guggenheim expressed that the creative team wanted to "chart [their] own course, [their] own destiny", and avoid any direct connections to Smallville, which featured its own Green Arrow/Oliver Queen who was portrayed by Hartley. Instead, they opted to cast a new actor in the titular role.[28] Amell, who was already in shape from Rent-a-Goalie, did physical fitness training at Tempest Freerunning Academy out of Reseda, California. He received archery training as well, which included watching a video on how archery has been displayed inaccurately or poorly in television and film before learning the basics of shooting a bow.[28] For Amell, the appeal of portraying Queen was that he saw multiple roles tied to the same character: "There's Queen the casual playboy; Queen the wounded hero; Queen the brooding Hamlet; Queen the lover; Queen the man of action, and so on."[28]

text:
Developing chemistry
Amy Brenneman made a point of really befriending me before we started shooting [Private Practice] [...] I was really taken with how she connected with me, person to person, before we tried to connect, actor to actor. So, I made a real point to do that [with the Arrow cast] [...] I think that you can see that [we hit it off] [...] If you have to put your hand on somebody's shoulder, if you've done it before, it makes it easier to do. Sometimes it's imperceptible, but I think it's what takes things from good to great, or from 2D to 3D.
Amell interview with Collider[34]

text: A week later, David Ramsey was cast as the original character John Diggle, named after the Green Arrow: Year One writer Andy Diggle.[35] Ramsey enjoyed the fact that he did not have to worry about matching the comic books. It allowed him to "just kind of take [his character], and run with it".[36] On February 14, 2012 Susanna Thompson was cast as Moira Queen.[37] The following day, Katie Cassidy and Willa Holland were announced to play Laurel Lance and Thea Queen, respectively. Laurel Lance is an attorney and Oliver's ex-girlfriend, named after Dinah Laurel Lance, who "may or may not end up being the Black Canary with time".[38] Cassidy said she was drawn to the show by Berlanti, Nutter, Kreisberg, and Guggenheim, whom she called smart, creative, and edgy.[39] Hollands' character is described as "Oliver's celebutante younger sister who's testing the boundaries of acceptable behavior".[40] She is partially based on the character Mia Dearden, sharing her middle name, using Mia as an alias in Season 3 and taking the codename "Speedy" in the season 3 finale. Subsequently. Brian Markinson was cast as guest-star villain Adam Hunt, described as "Hunt is a corrupt businessman who is ripping off some people — behavior that has gotten the attention of Dinah Laurel Lance and her CNRI firm".[41] On February 21, 2012 Colin Donnell was cast as Tommy Merlyn, named after Green Arrow's archenemy Merlyn. He is described as "Oliver's best friend, a playboy “trustafarian” who assumes the good times will roll again now that Oliver has returned, only to learn Oliver is a changed man".[42] On March 2, 2012, Paul Blackthorne and Jamey Sheridan were cast as Quentin Lance and Robert Queen, the fathers of Laurel and Oliver respectively, with Blackthorne being the last regular cast member to be cast.[43] Jacqueline MacInnes Wood was cast as Sara Lance, Laurel's sister, for the pilot. However, when the character returned in the second season, Wood was replaced by Caity Lotz.[44]

text: Filming[edit]

text: Production on the pilot began in March 2012 in Vancouver, British Columbia, Canada.[45] The series features two distinct timelines, which requires more specific planning in the filming schedule. Filming for the island flashbacks takes place in Vancouver's Whytecliff Park area, near beachfront homes. The production team is tasked with keeping the buildings out of camera frame.[31] Additionally, producer Marc Guggenheim finds the process arduous: "Stephen [Amell] has to wear a wig, and his look has to be changed... there's a lot. It's actually incredibly ambitious to do these flashbacks every week, every single episode. Because like Andrew [Kreisberg] said, it's almost like it's its own show."[31] Hatley Castle, located in Royal Roads University was used for exterior shots for the Queen family mansion. Hatley Castle had previously been used as the Luthor ancestral home in Smallville.[46] Vancouver's Terminal City Ironworks Complex doubles as the exterior for Queen Industrial, Inc, in which Oliver sets up his hideout and later his club Verdant.[47] It has also been used on several other occasions, such as the warehouse in which Oliver and Tommy are kidnapped in the pilot episode, or the base of operations for the Chinese Triad in episode 108 "Vendetta".[48]

text: Filming for the rest of the season commenced on July 18, 2012 and finalized on April 18, 2013.

text: Costumes[edit]

text:
"Arrow, we really wanted him urban, and sexy, and you could almost wear the costume down the street and it would look cool in today's world. That was a big goal with Arrow and the way the story was set up with his character."
—Costume Designer Colleen Atwood[49]

text: The realistic approach to the series included the costume design for Oliver's vigilante persona, created by Colleen Atwood.[50] According to Amell, it was important for the suit to be functional, and the best way that he knew for that was if he could put the costume on by himself: "If I can put it on by myself, I think that people will buy it. And that was our idea. That's our world. My boots are actually Nike Frees, which is kind of cool. It's leather and it's tight and it's aggressive, but I can move in it. People will like it."[29][51] David Nutter, the director of the pilot episode, said that "We're creating a real, believable world in which Oliver Queen can do incredible things. Colleen Atwood's great work on the Arrow costume reflects that effort."[52]

text: Music[edit]

text:
Arrow - Original Television Soundtrack: Season 1Soundtrack album by Blake NeelyReleased
September 17, 2013 (2013-09-17)Length
1:17:35Label
WaterTower MusicBlake Neely chronology

Arrow - Original Television Soundtrack: Season 1

Arrow - Original Television Soundtrack: Season 2

text: To compose the score for Arrow, executive producer Greg Berlanti invited Blake Neely, with whom he had first worked with on Everwood, Neely created a score that combined electronic and orchestral cues, varying between action themes and romantic ones.[53] Berlanti told Neely the series would be dark, and the music should be as well. After reading the pilot script, Neely went away to start composing on his own.[54] According to Neely, "Of course, Oliver has his main theme but also sub-themes for the many layers of his character. He and Laurel have a love theme. Mom had a theme for the Undertaking. The bad guys all have themes, which makes it sad for me when one of them dies. So I try not to become attached to bad guy themes. Diggle has a theme. Even the Island itself has a theme."[53] The soundtrack was released on September 17, 2013. It was composed by Blake Neely.

text: showTrack listingNo.TitleLength1."Five Years"1:542."Returning Home / Scars"2:533."City in Ruin"1:204."Setting Up the Lair"2:275."Loss and Regrets"2:386."On the List"1:407."Vigilante Justice"2:108."Honor Thy Father"1:459."Inhospitable Island / Deathstroke"2:0910."I Forgot Who I Was"4:0011."Train and Hunt"2:3812."Betrayed By Those You Love"1:5113."Chasing the Hood"2:2714."Damaged"1:3915."The Dark Archer / It Is I Who Failed This City"3:3116."Working Together But Alone"1:5317."The Count"2:0218."Friends in Arms"2:3619."Trust But Verify"2:3720."Join Us"1:5521."Trusting a Friend, Saving an Enemy"1:5722."Sins of the Father"1:2723."I Can't Lose You Twice"3:1724."Search for Salvation"3:2925."Shado Sees an Emerging Hero"1:5726."Unfinished Business / Saving Walter"2:2927."A Way Off the Island"2:1528."Sacrifice"4:5229."Oliver Queen Suite"9:47Total length:1:17:35

text: Reception[edit]

text: Critical response[edit]

text: The first season received favorable reviews, with a Metacritic score of 73 out of 100, based on reviews from 25 critics, making it the highest rated CW show in five years.[55][56] Review aggregation website Rotten Tomatoes calculated an approval rating of 86%, based on 35 reviews, for the first season. The site's consensus reads: "The CW nails the target with Arrow, a comic book-inspired series that benefits from cinematic action sequences, strong plotting, and intriguing characters."[57]

text: Mary McNamara of the Los Angeles Times called the series an interesting setup with a quality look, describing Amell as "a poster boy (no doubt literally) for the Katniss Everdeen set."[58] Brian Lowry at Variety described the series as a "handsome but stiff surrogate for Batman that could benefit from sharper execution."[59] In reviewing the final episode of the first season, Alasdair Wilkins of The A.V. Club gave the season as a whole a rating of B+, noting that the show "hasn't quite figured everything out yet, but it's had some standout episodes."[60]

text: Ratings[edit]

text: Arrow's premiere episode drew 4.14 million viewers, making it The CW's most-watched telecast of any show on any night in three years, and The CW's most-watched series premiere since The Vampire Diaries in 2009. In its second episode, Arrow became the only new network drama in the 2012–13 season to hold its ratings in both adults 18–34 and adults 18–49 from its premiere to its second week.[1] The first season finished as the 130th ranked show, with an average viewership of 3.68 million.[61] In Australia, the premiere received 1.32 million viewers, making it the third most-watched broadcast on the network that night.[62] The UK broadcast was the highest-rated telecast of the week on Sky 1, with 1.85 million viewers.[63] In Canada, the first episode got 1.32 million viewers, making it the fourth most-watched airing of the night and the twenty-third of the week.[64]

text:
No.

Title

Air date
Rating/share(18–49)
Viewers(millions)
DVR(18–49)
Total(18–49)

1

"Pilot"

October 10, 2012
1.3
4.14[2]
0.4
1.7

2

"Honor Thy Father"

October 17, 2012
1.3
3.55[3]
N/A
N/A

3

"Lone Gunmen"

October 24, 2012
1.1
3.51[4]
N/A
N/A

4

"An Innocent Man"

October 31, 2012
1.0/3
3.05[5]
0.5
1.5[65]

5

"Damaged"

November 7, 2012
1.3/4
3.75[6]
N/A
N/A

6

"Legacies"

November 14, 2012
1.2/3
3.83[7]
N/A
N/A

7

"Muse of Fire"

November 28, 2012
1.3/4
3.74[8]
N/A
N/A

8

"Vendetta"

December 5, 2012
1.1/3
3.35[9]
N/A
N/A

9

"Year's End"

December 12, 2012
1.0/3
3.11[10]
0.5
1.5[66]

10

"Burned"

January 16, 2013
1.1/3
3.06[11]
0.5
1.6[67]

11

"Trust But Verify"

January 23, 2013
1.1/3
3.14[12]
N/A
N/A

12

"Vertigo"

January 30, 2013
0.9/3
2.97[13]
0.5
1.4

13

"Betrayal"

February 6, 2013
1.0/3
2.96[14]
0.5
1.5[68]

14

"The Odyssey"

February 13, 2013
1.1/3
3.29[15]
N/A
N/A

15

"Dodger"

February 20, 2013
0.9/3
3.15[16]
0.5
1.4[69]

16

"Dead to Rights"

February 27, 2013
1.0/3
3.17[17]
N/A
N/A

17

"The Huntress Returns"

March 20, 2013
1.0/3
3.02[18]
N/A
N/A

18

"Salvation"

March 27, 2013
0.9/3
2.65[19]
0.5
1.4[70]

19

"Unfinished Business"

April 3, 2013
0.9/3
2.92[20]
0.4
1.3[71]

20

"Home Invasion"

April 24, 2013
1.0/3
3.10[21]
0.5
1.5[72]

21

"The Undertaking"

May 1, 2013
0.9/3
2.89[22]
N/A
N/A

22

"Darkness on the Edge of Town"

May 8, 2013
0.9/3
2.62[23]
N/A
N/A

23

"Sacrifice"

May 15, 2013
0.9/3
2.77[24]
0.4
1.3[73]

text: Accolades[edit]

text:
Year

Award

Category

Recipients

Outcome

2012

Satellite Awards[74]

Satellite Award for Best Television Series – Genre

Arrow

Nominated

IGN Awards[75]

Best TV Hero

Stephen Amell/Arrow

Nominated

2013

People's Choice Awards[76]

Favorite New TV Drama

Arrow

Nominated

Leo Awards[77][78]

Best Dramatic Series

Joseph Patrick Finn, Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, Melissa Kellner Berman, Drew Greenberg, Jennifer Lence, Wendy Mericle, Carl Ogawa

Nominated

Cinematography

Glen Winter ("Pilot")

Won

Gordon Verheul ("Lone Gunman")

Nominated

Best Visual Effects

Jean-Luc Dinsdale, Pauline Burns, Andrew Orloff, Dave Gauthier ("Burned")

Won

Best Production Design

Richard Hudolin ("Pilot")

Won

Best Casting

Coreen Mayrs, Heike Brandstatter ("An Innocent Man")

Nominated

Best Stunt Coordination

J.J. Makaro ("Pilot")

Won

J.J. Makaro ("Vertigo")

Nominated

NewNowNext Awards[79]

Best New Indulgence

Arrow

Nominated

Cause You're Hot

Stephen Amell

Nominated

Saturn Awards[80]

Best Youth-Oriented Series on Television

Arrow

Nominated

Teen Choice Awards[81]

Choice TV Show: Fantasy/Sci-Fi

Nominated

Choice TV Breakout Show

Nominated

Choice TV Actor: Fantasy/Sci-Fi

Stephen Amell

Nominated

Choice TV Breakout Star

Nominated

Choice TV Actress: Fantasy/Sci-Fi

Katie Cassidy

Nominated

Canadian Society of Cinematography Awards[82]

Cinematographer Awards for TV Drama Cinematography

Glen Winter csc, Arrow ("Pilot")

Won

Broadcast Music, Inc.[83]

BMI Television Music Awards

Blake Neely

Won

text: Home media[edit]

text: Arrow: Season 1 was released as a 5-disc DVD set and as a 9-disc Blu-ray/DVD Combo Pack set on September 17, 2013 in the United States and September 23, 2013 in the United Kingdom. The DVD/Blu-ray box sets contain additional features, including making-of featurettes, deleted scenes, gag reel, and highlights from the Paley Fest 2012.[84]

text: Notes[edit]

text:
Jump up ^ In addition to an uncredited role in "Year's End", Rickards also co-starred in two episodes.

Jump up ^ Laing co-starred in two episodes before she was promoted to recurring in the ninth episode.

Jump up ^ Also credited as a co-star in two episodes.


document_title: Large Hadron Collider

question_text: when was the large hadron collider first turned on

question_tokens: when was the large hadron collider first turned on

root

text: Large Hadron Collider

text: Background[edit]

text: The term hadron refers to composite particles composed of quarks held together by the strong force (as atoms and molecules are held together by the electromagnetic force).[17] The best-known hadrons are the baryons such as protons and neutrons; hadrons also include mesons such as the pion and kaon, which were discovered during cosmic ray experiments in the late 1940s and early 1950s.[18]

tag: p

text: A collider is a type of a particle accelerator with two directed beams of particles. In particle physics, colliders are used as a research tool: they accelerate particles to very high kinetic energies and let them impact other particles.[19] Analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it. Many of these byproducts are produced only by high-energy collisions, and they decay after very short periods of time. Thus many of them are hard or nearly impossible to study in other ways.[20]

text: Purpose[edit]

text: Physicists hope that the Large Hadron Collider will help answer some of the fundamental open questions in physics, concerning the basic laws governing the interactions and forces among the elementary objects, the deep structure of space and time, and in particular the interrelation between quantum mechanics and general relativity.

text: Data is also needed from high-energy particle experiments to suggest which versions of current scientific models are more likely to be correct – in particular to choose between the Standard Model and Higgsless model and to validate their predictions and allow further theoretical development. Many theorists expect new physics beyond the Standard Model to emerge at the TeV energy level, as the Standard Model appears to be unsatisfactory. Issues explored by LHC collisions include:[21][22]

text:
is the mass of elementary particles being generated by the Higgs mechanism via electroweak symmetry breaking?[23] It was expected that the collider experiments will either demonstrate or rule out the existence of the elusive Higgs boson, thereby allowing physicists to consider whether the Standard Model or its Higgsless alternatives are more likely to be correct.[24][25][26] The ATLAS and CMS experiments discovered the Higgs boson, which is strong evidence that the Standard Model has the correct mechanism of giving mass to elementary particles.
is supersymmetry, an extension of the Standard Model and Poincaré symmetry, realized in nature, implying that all known particles have supersymmetric partners?[27][28][29]
Are there extra dimensions,[30] as predicted by various models based on string theory, and can we detect them?[31]
What is the nature of the dark matter that appears to account for 27% of the mass-energy of the universe?

tag: ul

text: Other open questions that may be explored using high-energy particle collisions:

text:
It is already known that electromagnetism and the weak nuclear force are different manifestations of a single force called the electroweak force. The LHC may clarify whether the electroweak force and the strong nuclear force are similarly just different manifestations of one universal unified force, as predicted by various Grand Unification Theories.
Why is the fourth fundamental force (gravity) so many orders of magnitude weaker than the other three fundamental forces? See also Hierarchy problem.
Are there additional sources of quark flavour mixing, beyond those already present within the Standard Model?
Why are there apparent violations of the symmetry between matter and antimatter? See also CP violation.
What are the nature and properties of quark–gluon plasma, thought to have existed in the early universe and in certain compact and strange astronomical objects today? This will be investigated by heavy ion collisions, mainly in ALICE, but also in CMS, ATLAS and LHCb. First observed in 2010, findings published in 2012 confirmed the phenomenon of jet quenching in heavy-ion collisions.[32][33][34]

text: Design[edit]

text: The LHC is the world's largest and highest-energy particle accelerator.[35][36] The collider is contained in a circular tunnel, with a circumference of 27 kilometres (17 mi), at a depth ranging from 50 to 175 metres (164 to 574 ft) underground.

text: The 3.8-metre (12 ft) wide concrete-lined tunnel, constructed between 1983 and 1988, was formerly used to house the Large Electron–Positron Collider.[37] It crosses the border between Switzerland and France at four points, with most of it in France. Surface buildings hold ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants.

text: The collider tunnel contains two adjacent parallel beamlines (or beam pipes) each containing a beam, which travel in opposite directions around the ring. The beams intersect at four points around the ring, which is where the particle collisions take place. Some 1,232 dipole magnets keep the beams on their circular path (see image[38]), while an additional 392 quadrupole magnets are used to keep the beams focused, with stronger quadrupole magnets close to the intersection points in order to maximize the chances of interaction where the two beams cross. Magnets of higher multipole orders are used to correct smaller imperfections in the field geometry. In total, about 10,000 superconducting magnets are installed, with the dipole magnets having a mass of over 27 tonnes.[39] Approximately 96 tonnes of superfluid helium-4 is needed to keep the magnets, made of copper-clad niobium-titanium, at their operating temperature of 1.9 K (−271.25 °C), making the LHC the largest cryogenic facility in the world at liquid helium temperature.

text: When running at the current energy record of 6.5 TeV per proton,[40] once or twice a day, as the protons are accelerated from 450 GeV to 6.5 TeV, the field of the superconducting dipole magnets will be increased from 0.54 to 7.7 teslas (T). The protons each have an energy of 6.5 TeV, giving a total collision energy of 13 TeV. At this energy the protons have a Lorentz factor of about 6,930 and move at about 0.999999990 c, or about 3.1 m/s (11 km/h) slower than the speed of light (c). It takes less than 90 microseconds (μs) for a proton to travel once around the main ring – a speed of about 11,000 revolutions per second. Rather than having continuous beams, the protons are bunched together, into up to 2,808 bunches, with 115 billion protons in each bunch so that interactions between the two beams take place at discrete intervals, mainly 25 nanoseconds (ns) apart, providing a bunch collision rate of 40 MHz. It was operated with fewer bunches in the first years. The design luminosity of the LHC is 1034 cm−2s−1,[41] which was first reached in June 2016.[42] By 2017 twice this value was achieved.[43]

text: Prior to being injected into the main accelerator, the particles are prepared by a series of systems that successively increase their energy. The first system is the linear particle accelerator LINAC 2 generating 50-MeV protons, which feeds the Proton Synchrotron Booster (PSB). There the protons are accelerated to 1.4 GeV and injected into the Proton Synchrotron (PS), where they are accelerated to 26 GeV. Finally the Super Proton Synchrotron (SPS) is used to further increase their energy to 450 GeV before they are at last injected (over a period of several minutes) into the main ring. Here the proton bunches are accumulated, accelerated (over a period of 20 minutes) to their peak energy, and finally circulated for 5 to 24 hours while collisions occur at the four intersection points.[44]

text: The LHC physics programme is mainly based on proton–proton collisions. However, shorter running periods, typically one month per year, with heavy-ion collisions are included in the programme. While lighter ions are considered as well, the baseline scheme deals with lead ions[45] (see A Large Ion Collider Experiment). The lead ions are first accelerated by the linear accelerator LINAC 3, and the Low Energy Ion Ring (LEIR) is used as an ion storage and cooler unit. The ions are then further accelerated by the PS and SPS before being injected into LHC ring, where they reached an energy of 2.3 TeV per nucleon (or 522 TeV per ion),[46] higher than the energies reached by the Relativistic Heavy Ion Collider. The aim of the heavy-ion programme is to investigate quark–gluon plasma, which existed in the early universe.

text: Detectors[edit]

text: Seven detectors have been constructed at the LHC, located underground in large caverns excavated at the LHC's intersection points. Two of them, the ATLAS experiment and the Compact Muon Solenoid (CMS), are large, general purpose particle detectors.[36] ALICE and LHCb have more specific roles and the last three, TOTEM, MoEDAL and LHCf, are very much smaller and are for very specialized research. The BBC's summary of the main detectors is:[47]

text:
Detector
Description

ATLAS
One of two general purpose detectors. ATLAS studies the Higgs boson and looks for signs of new physics, including the origins of mass and extra dimensions.

CMS
The other general purpose detector, like ATLAS, studies the Higgs boson and look for clues of new physics.

ALICE
ALICE is studying a "fluid" form of matter called quark–gluon plasma that existed shortly after the Big Bang.

LHCb
Equal amounts of matter and antimatter were created in the Big Bang. LHCb investigates what happened to the "missing" antimatter.

tag: table

text: Computing and analysis facilities[edit]

text: Data produced by LHC, as well as LHC-related simulation, was estimated at approximately 15 petabytes per year (max throughput while running not stated)[48] - a major challenge in its own right at the time.

text: The LHC Computing Grid[49] was constructed as part of the LHC design, to handle the massive amounts of data expected for its collisions. It is an international collaborative project that consists of a grid-based computer network infrastructure initially connecting 140 computing centres in 35 countries (over 170 in 36 countries as of 2012). It was designed by CERN to handle the significant volume of data produced by LHC experiments,[12][13] incorporating both private fibre optic cable links and existing high-speed portions of the public Internet to enable data transfer from CERN to academic institutions around the world.[50] The Open Science Grid is used as the primary infrastructure in the United States, and also as part of an interoperable federation with the LHC Computing Grid.

text: The distributed computing project LHC@home was started to support the construction and calibration of the LHC. The project uses the BOINC platform, enabling anybody with an Internet connection and a computer running Mac OS X, Windows or Linux, to use their computer's idle time to simulate how particles will travel in the beam pipes. With this information, the scientists are able to determine how the magnets should be calibrated to gain the most stable "orbit" of the beams in the ring.[51] In August 2011, a second application went live (Test4Theory) which performs simulations against which to compare actual test data, to determine confidence levels of the results.

text: By 2012 data from over 6 quadrillion (6 x 1015) LHC proton-proton collisions had been analysed,[52] LHC collision data was being produced at approximately 25 petabytes per year, and the LHC Computing Grid had become the world's largest computing grid (as of 2012), comprising over 170 computing facilities in a worldwide network across 36 countries.[14][15][16]

text: Operational history[edit]

text: The LHC first went live on 10 September 2008,[53] but initial testing was delayed for 14 months from 19 September 2008 to 20 November 2009, following a magnet quench incident that caused extensive damage to over 50 superconducting magnets, their mountings, and the vacuum pipe.[54][55][56][57][58]

text: During its first run (2010–2013) the LHC collided two opposing particle beams of either protons at up to 4 teraelectronvolts (4 TeV or 0.64 microjoules), or lead nuclei (574 TeV per nucleus, or 2.76 TeV per nucleon).[35][59] Its first run discoveries included the long sought Higgs boson, several composite particles (hadrons) like the χb (3P) bottomonium state, the first creation of a quark–gluon plasma, and the first observations of the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−), which challenged the validity of existing models of supersymmetry.[60]

text: Construction[edit]

text: Operational challenges[edit]

text: The size of the LHC constitutes an exceptional engineering challenge with unique operational issues on account of the amount of energy stored in the magnets and the beams.[44][61] While operating, the total energy stored in the magnets is 10 GJ (2,400 kilograms of TNT) and the total energy carried by the two beams reaches 724 MJ (173 kilograms of TNT).[62]

text: Loss of only one ten-millionth part (10−7) of the beam is sufficient to quench a superconducting magnet, while each of the two beam dumps must absorb 362 MJ (87 kilograms of TNT). These energies are carried by very little matter: under nominal operating conditions (2,808 bunches per beam, 1.15×1011 protons per bunch), the beam pipes contain 1.0×10−9 gram of hydrogen, which, in standard conditions for temperature and pressure, would fill the volume of one grain of fine sand.

text: Cost[edit]

text: With a budget of €7.5 billion (approx. $9bn or £6.19bn as of June 2010), the LHC is one of the most expensive scientific instruments[63] ever built.[64] The total cost of the project is expected to be of the order of 4.6bn Swiss francs (SFr) (approx. $4.4bn, €3.1bn, or £2.8bn as of Jan 2010) for the accelerator and 1.16bn (SFr) (approx. $1.1bn, €0.8bn, or £0.7bn as of Jan 2010) for the CERN contribution to the experiments.[65]

text: The construction of LHC was approved in 1995 with a budget of SFr 2.6bn, with another SFr 210M towards the experiments. However, cost overruns, estimated in a major review in 2001 at around SFr 480M for the accelerator, and SFr 50M for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007.[66] The superconducting magnets were responsible for SFr 180M of the cost increase. There were also further costs and delays due to engineering difficulties encountered while building the underground cavern for the Compact Muon Solenoid,[67] and also due to magnet supports which were insufficiently strongly designed and failed their initial testing (2007) and damage from a magnet quench and liquid helium escape (inaugural testing, 2008) (see: Construction accidents and delays).[68] Due to lower electricity costs during the summer, the LHC normally does not operate over the winter months,[69] although exceptions over the 2009/10 and 2012/2013 winters were made to make up for the 2008 start-up delays and to improve precision of measurements of the new particle discovered in 2012, respectively.

text: Construction accidents and delays[edit]

text:
On 25 October 2005, José Pereira Lages, a technician, was killed in the LHC when a switchgear that was being transported fell on top of him.[70]
On 27 March 2007 a cryogenic magnet support designed and provided by Fermilab and KEK broke during an initial pressure test involving one of the LHC's inner triplet (focusing quadrupole) magnet assemblies. No one was injured. Fermilab director Pier Oddone stated "In this case we are dumbfounded that we missed some very simple balance of forces". This fault had been present in the original design, and remained during four engineering reviews over the following years.[71] Analysis revealed that its design, made as thin as possible for better insulation, was not strong enough to withstand the forces generated during pressure testing. Details are available in a statement from Fermilab, with which CERN is in agreement.[72][73] Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date, then planned for November 2007.
On 19 September 2008, during initial testing, a faulty electrical connection led to a magnet quench (the sudden loss of a superconducting magnet's superconducting ability due to warming or electric field effects). Six tonnes of supercooled liquid helium—used to cool the magnets—escaped, with sufficient force to break 10-ton magnets nearby from their mountings, and caused considerable damage and contamination of the vacuum tube (see 2008 quench incident); repairs and safety checks caused a delay of around 14 months.[74][75][76]
Two vacuum leaks were found in July 2009, and the start of operations was further postponed to mid-November 2009.[77]

text: Initial lower magnet currents[edit]

text: In both of its runs (2010 to 2012 and 2015), the LHC was initially run at energies below its planned operating energy, and ramped up to just 2 x 4 TeV energy on its first run and 2 x 6.5 TeV on its second run, below the design energy of 2 x 7 TeV. This is because massive superconducting magnets require considerable magnet training to handle the high currents involved without losing their superconducting ability, and the high currents are necessary to allow a high proton energy. The "training" process involves repeatedly running the magnets with lower currents to provoke any quenches or minute movements that may result. It also takes time to cool down magnets to their operating temperature of around 1.9 K (close to absolute zero). Over time the magnet "beds in" and ceases to quench at these lesser currents and can handle the full design current without quenching; CERN media describe the magnets as "shaking out" the unavoidable tiny manufacturing imperfections in their crystals and positions that had initially impaired their ability to handle their planned currents. The magnets over time and with training, gradually become able to handle their full planned currents without quenching.[78][79]

text: Inaugural tests (2008)[edit]

text: The first beam was circulated through the collider on the morning of 10 September 2008.[47] CERN successfully fired the protons around the tunnel in stages, three kilometres at a time. The particles were fired in a clockwise direction into the accelerator and successfully steered around it at 10:28 local time.[53] The LHC successfully completed its major test: after a series of trial runs, two white dots flashed on a computer screen showing the protons travelled the full length of the collider. It took less than one hour to guide the stream of particles around its inaugural circuit.[80] CERN next successfully sent a beam of protons in an anticlockwise direction, taking slightly longer at one and a half hours due to a problem with the cryogenics, with the full circuit being completed at 14:59.

text: Quench incident[edit]

text: Wikinews has related news: CERN says repairs to LHC particle accelerator to cost €16.6 million

text: On 19 September 2008, a magnet quench occurred in about 100 bending magnets in sectors 3 and 4, where an electrical fault led to a loss of approximately six tonnes of liquid helium (the magnets' cryogenic coolant), which was vented into the tunnel. The escaping vapour expanded with explosive force, damaging total 53 superconducting magnets and their mountings, and contaminating the vacuum pipe, which also lost vacuum conditions.[54][55][81]

text: Shortly after the incident CERN reported that the most likely cause of the problem was a faulty electrical connection between two magnets, and that – due to the time needed to warm up the affected sectors and then cool them back down to operating temperature – it would take at least two months to fix.[82] CERN released an interim technical report[81] and preliminary analysis of the incident on 15 and 16 October 2008 respectively,[83] and a more detailed report on 5 December 2008.[75] The analysis of the incident by CERN confirmed that an electrical fault had indeed been the cause. The faulty electrical connection had led (correctly) to a failsafe power abort of the electrical systems powering the superconducting magnets, but had also caused an electric arc (or discharge) which damaged the integrity of the supercooled helium's enclosure and vacuum insulation, causing the coolant's temperature and pressure to rapidly rise beyond the ability of the safety systems to contain it,[81] and leading to a temperature rise of about 100 degrees Celsius in some of the affected magnets. Energy stored in the superconducting magnets and electrical noise induced in other quench detectors also played a role in the rapid heating. Around two tonnes of liquid helium escaped explosively before detectors triggered an emergency stop, and a further four tonnes leaked at lower pressure in the aftermath.[81] A total of 53 magnets were damaged in the incident and were repaired or replaced during the winter shutdown.[84] This accident was thoroughly discussed in a 22 February 2010 Superconductor Science and Technology article by CERN physicist Lucio Rossi.[85]

text: In the original timeline of the LHC commissioning, the first "modest" high-energy collisions at a centre-of-mass energy of 900 GeV were expected to take place before the end of September 2008, and the LHC was expected to be operating at 10 TeV by the end of 2008.[86] However, due to the delay caused by the above-mentioned incident, the collider was not operational until November 2009.[87] Despite the delay, LHC was officially inaugurated on 21 October 2008, in the presence of political leaders, science ministers from CERN's 20 Member States, CERN officials, and members of the worldwide scientific community.[88]

text: Most of 2009 was spent on repairs and reviews from the damage caused by the quench incident, along with two further vacuum leaks identified in July 2009 which pushed the start of operations to November of that year.[77]

text: Run 1: first operational run (2009–2013)[edit]

text: On 20 November 2009, low-energy beams circulated in the tunnel for the first time since the incident, and shortly after, on 30 November, the LHC achieved 1.18 TeV per beam to become the world's highest-energy particle accelerator, beating the Tevatron's previous record of 0.98 TeV per beam held for eight years.[90]

text: The early part of 2010 saw the continued ramp-up of beam in energies and early physics experiments towards 3.5 TeV per beam and on 30 March 2010, LHC set a new record for high-energy collisions by colliding proton beams at a combined energy level of 7 TeV. The attempt was the third that day, after two unsuccessful attempts in which the protons had to be "dumped" from the collider and new beams had to be injected.[91] This also marked the start of the main research programme.

text: The first proton run ended on 4 November 2010. A run with lead ions started on 8 November 2010, and ended on 6 December 2010,[92] allowing the ALICE experiment to study matter under extreme conditions similar to those shortly after the Big Bang.[93]

text: CERN originally planned that the LHC would run through to the end of 2012, with a short break at the end of 2011 to allow for an increase in beam energy from 3.5 to 4 TeV per beam.[4] At the end of 2012 the LHC was planned to get shut down until around 2015 to allow upgrade to a planned beam energy of 7 TeV per beam.[94] In late 2012, in light of the July 2012 discovery of the Higgs boson, the shutdown was postponed for some weeks into early 2013, to allow additional data to be obtained prior to shutdown.

text: Upgrade (2013–2015)[edit]

text: The LHC was shut down on 13 February 2013 for its 2-year upgrade, which would touch on many aspects of the LHC: enabling collisions at 14 TeV, enhancing its detectors and pre-accelerators (the Proton Synchrotron and Super Proton Synchrotron), as well as replacing its ventilation system and 100 km of cabling impaired by high-energy collisions from its first run.[95] The upgraded collider began its long start-up and testing process in June 2014, with the Proton Synchrotron Booster starting on 2 June 2014, the final interconnection between magnets completing and the Proton Synchrotron circulating particles on 18 June 2014, and the first section of the main LHC supermagnet system reaching operating temperature of 1.9 K (−271.25 °C), a few days later.[96] Due to the slow progress with "training" the superconducting magnets, it was decided to start the second run with a lower energy of 6.5 TeV per beam, corresponding to a current of 11,000 amperes. The first of the main LHC magnets were reported to have been successfully trained by 9 December 2014, while training the other magnet sectors was finished in March 2015.[97]

text: Run 2: second operational run (2015–2018)[edit]

text: On 5 April 2015, the LHC restarted after a two-year break, during which the electrical connectors between the bending magnets were upgraded to safely handle the current required for 7 TeV per beam (14 TeV).[5][98] However, the bending magnets were only trained to handle up to 6.5 TeV per beam (13 TeV total), which became the operating energy for 2015 to 2017.[99] The energy was first reached on 10 April 2015.[100] The upgrades culminated in colliding protons together with a combined energy of 13 TeV.[101] On 3 June 2015 the LHC started delivering physics data after almost two years offline.[102] In the following months it was used for proton-proton collisions, while in November the machine switched to collisions of lead ions and in December the usual winter shutdown started.

text: In 2016, the machine operators focused on increasing the luminosity for proton-proton collisions. The design value was first reached 29 June,[42] and further improvements increased the collision rate to 40% above the design value.[103] The total number of collisions in 2016 exceeded the number from Run 1 - at a higher energy per collision. The proton-proton run was followed by four weeks of proton-lead collisions.[104]

text: In 2017 the luminosity could be increased further and reached twice the design value. The total number of collisions was higher than in 2016 as well.[43]

text: Timeline of operations[edit]

text:
Date
Event

10 Sep 2008
CERN successfully fired the first protons around the entire tunnel circuit in stages.

19 Sep 2008
Magnetic quench occurred in about 100 bending magnets in sectors 3 and 4, causing a loss of approximately 6 tonnes of liquid helium.

30 Sep 2008
First "modest" high-energy collisions planned but postponed due to accident.[39]

16 Oct 2008
CERN released a preliminary analysis of the accident.

21 Oct 2008
Official inauguration.

5 Dec 2008
CERN released detailed analysis.

20 Nov 2009
Low-energy beams circulated in the tunnel for the first time since the accident.[57]

23 Nov 2009
First particle collisions in all four detectors at 450 GeV.

30 Nov 2009
LHC becomes the world's highest-energy particle accelerator achieving 1.18 TeV per beam, beating the Tevatron's previous record of 0.98 TeV per beam held for eight years.[90]

15 Dec 2009
First scientific results, covering 284 collisions in the ALICE detector.[105]

30 Mar 2010
The two beams collided at 7 TeV (3.5 TeV per beam) in the LHC at 13:06 CEST, marking the start of the LHC research programme.

8 Nov 2010
Start of the first run with lead ions.

6 Dec 2010
End of the run with lead ions. Shutdown until early 2011.

13 Mar 2011
Beginning of the 2011 run with proton beams.[106]

21 Apr 2011
LHC becomes the world's highest-luminosity hadron accelerator achieving a peak luminosity of 4.67·1032 cm−2s−1, beating the Tevatron's previous record of 4·1032 cm−2s−1 held for one year.[107]

24 May 2011
ALICE reports that a Quark–gluon plasma has been achieved with earlier lead collisions.[108]

17 Jun 2011
The high-luminosity experiments ATLAS and CMS reach 1 fb−1 of collected data.[109]

14 Oct 2011
LHCb reaches 1 fb−1 of collected data.[110]

23 Oct 2011
The high-luminosity experiments ATLAS and CMS reach 5 fb−1 of collected data.

Nov 2011
Second run with lead ions.

22 Dec 2011
First new composite particle discovery, the χb (3P) bottomonium meson, observed with proton-proton collisions in 2011.[111]

5 Apr 2012
First collisions with stable beams in 2012 after the winter shutdown. The energy is increased to 4 TeV per beam (8 TeV in collisions).[112]

4 Jul 2012
First new elementary particle discovery, a new boson observed that is "consistent with" the theorized Higgs boson. (This has now been confirmed as the Higgs boson itself.[113])

8 Nov 2012
First observation of the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−), a major test of supersymmetry theories,[114] shows results at 3.5 sigma that match the Standard Model rather than many of its super-symmetrical variants.

20 Jan 2013
Start of the first run colliding protons with Lead ions.

11 Feb 2013
End of the first run colliding protons with Lead ions.

14 Feb 2013
Beginning of the first long shutdown to prepare the collider for a higher energy and luminosity.[115]

7 Mar 2015
Injection tests for Run 2 send protons towards LHCb & ALICE

5 Apr 2015
Both beams circulated in the collider.[5] Four days later, a new record energy of 6.5 TeV per proton was achieved.[116]

20 May 2015

Protons collided in the LHC at the record-breaking collision energy of 13 TeV.[101]

3 Jun 2015
Start of delivering the physics data after almost two years offline for re-commissioning.[102]

4 Nov 2015
End of proton collisions in 2015, start of preparations for ion collisions.

25 Nov 2015
First ion collisions at a record-breaking energy of more than 1 PeV (1015 eV)[117]

13 Dec 2015
End of ion collisions in 2015

23 Apr 2016
Data-taking in 2016 begins

29 June 2016
The LHC achieves a luminosity of 1.0 · 1034 cm−2s−1, its design value.[42] Further improvements over the year increased the luminosity to 40% above the design value.[103]

26 Oct 2016
End of 2016 proton-proton collisions

10 Nov 2016
Beginning of 2016 proton-lead collisions

3 Dec 2016
End of 2016 proton-lead collisions

24 May 2017
Start of 2017 proton-proton collisions. During 2017, the luminosity increased to twice its design value.[43]

10 Nov 2017
End of regular 2017 proton-proton collision mode.[43]

text: Findings and discoveries[edit]

text: An initial focus of research was to investigate the possible existence of the Higgs boson, a key part of the Standard Model of physics which is predicted by theory but had not yet been observed before due to its high mass and elusive nature. CERN scientists estimated that, if the Standard Model were correct, the LHC would produce several Higgs bosons every minute, allowing physicists to finally confirm or disprove the Higgs boson's existence. In addition, the LHC allowed the search for supersymmetric particles and other hypothetical particles as possible unknown areas of physics.[35] Some extensions of the Standard Model predict additional particles, such as the heavy W' and Z' gauge bosons, which are also estimated to be within reach of the LHC to discover.[118]

text: First run (data taken 2009–2013)[edit]

text: The first physics results from the LHC, involving 284 collisions which took place in the ALICE detector, were reported on 15 December 2009.[105] The results of the first proton–proton collisions at energies higher than Fermilab's Tevatron proton–antiproton collisions were published by the CMS collaboration in early February 2010, yielding greater-than-predicted charged-hadron production.[119]

text: After the first year of data collection, the LHC experimental collaborations started to release their preliminary results concerning searches for new physics beyond the Standard Model in proton-proton collisions.[120][121][122][123] No evidence of new particles was detected in the 2010 data. As a result, bounds were set on the allowed parameter space of various extensions of the Standard Model, such as models with large extra dimensions, constrained versions of the Minimal Supersymmetric Standard Model, and others.[124][125][126]

text: On 24 May 2011, it was reported that quark–gluon plasma (the densest matter thought to exist besides black holes) had been created in the LHC.[108]

text: Between July and August 2011, results of searches for the Higgs boson and for exotic particles, based on the data collected during the first half of the 2011 run, were presented in conferences in Grenoble[127] and Mumbai.[128] In the latter conference it was reported that, despite hints of a Higgs signal in earlier data, ATLAS and CMS exclude with 95% confidence level (using the CLs method) the existence of a Higgs boson with the properties predicted by the Standard Model over most of the mass region between 145 and 466 GeV.[129] The searches for new particles did not yield signals either, allowing to further constrain the parameter space of various extensions of the Standard Model, including its supersymmetric extensions.[130][131]

text: On 13 December 2011, CERN reported that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 115–130 GeV. Both the CMS and ATLAS detectors have also shown intensity peaks in the 124–125 GeV range, consistent with either background noise or the observation of the Higgs boson.[132]

text: On 22 December 2011, it was reported that a new composite particle had been observed, the χb (3P) bottomonium state.[111]

text: On 4 July 2012, both the CMS and ATLAS teams announced the discovery of a boson in the mass region around 125–126 GeV, with a statistical significance at the level of 5 sigma each. This meets the formal level required to announce a new particle. The observed properties were consistent with the Higgs boson, but scientists were cautious as to whether it is formally identified as actually being the Higgs boson, pending further analysis.[133]

text: On 8 November 2012, the LHCb team reported on an experiment seen as a "golden" test of supersymmetry theories in physics,[114] by measuring the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−). The results, which match those predicted by the non-supersymmetrical Standard Model rather than the predictions of many branches of supersymmetry, show the decays are less common than some forms of supersymmetry predict, though could still match the predictions of other versions of supersymmetry theory. The results as initially drafted are stated to be short of proof but at a relatively high 3.5 sigma level of significance.[134] The result was later confirmed by the CMS collaboration.[135]

text: In August 2013 the LHCb team revealed an anomaly in the angular distribution of B meson decay products which could not be predicted by the Standard Model; this anomaly had a statistical certainty of 4.5 sigma, just short of the 5 sigma needed to be officially recognized as a discovery. It is unknown what the cause of this anomaly would be, although the Z' boson has been suggested as a possible candidate.[136]

text:
On 19 November 2014, the LHCb experiment announced the discovery of two new heavy subatomic particles, Ξ′−
b and Ξ∗−
b. Both of them are baryons that are composed of one bottom, one down, and one strange quark. They are excited states of the bottom Xi baryon.[137][138]

text:
The LHCb collaboration has observed multiple exotic hadrons, possibly pentaquarks or tetraquarks, in the Run 1 data. On 4 April 2014, the collaboration confirmed the existence of the tetraquark candidate Z(4430) with a significance of over 13.9 sigma.[139][140] On 13 July 2015, results consistent with pentaquark states in the decay of bottom Lambda baryons (Λ0
b) were reported.[141][142][143] On 28 June 2016, the collaboration announced four tetraquark-like particles decaying into a J/ψ and a φ meson, only one of which was well established before (X(4274), X(4500) and X(4700) and X(4140)).[144][145]

text: In December 2016, ATLAS presented a measurement of the W boson mass, researching the precision of analyses done at the Tevatron.[146]

text: Second run (2015 onward)[edit]

text: At the conference EPS-HEP 2015 in July, the collaborations presented first cross-section measurements of several particles at the higher collision energy.

text: On 15 December 2015, the ATLAS and CMS experiments both reported a number of preliminary results for Higgs physics, supersymmetry (SUSY) searches and exotics searches using 13 TeV proton collision data. Both experiments saw a moderate excess around 750 GeV in the two-photon invariant mass spectrum,[147][148][149] but the experiments did not confirm the existence of the hypothetical particle in an August 2016 report.[150][151][152]

text: In July 2017, many analysis based on the large dataset collected in 2016 were shown. The properties of the Higgs boson were studied in more detail and the precision of many other results was improved.[153]

text: Planned "high-luminosity" upgrade[edit]

text: After some years of running, any particle physics experiment typically begins to suffer from diminishing returns: as the key results reachable by the device begin to be completed, later years of operation discover proportionately less than earlier years. A common response is to upgrade the devices involved, typically in collision energy, luminosity, or improved detectors. In addition to a possible increase to 14 TeV collision energy in 2018, a luminosity upgrade of the LHC, called the High Luminosity LHC, is planned,[154] to be made after 2022.

text: Safety of particle collisions[edit]

text: The experiments at the Large Hadron Collider sparked fears that the particle collisions might produce doomsday phenomena, involving the production of stable microscopic black holes or the creation of hypothetical particles called strangelets.[155] Two CERN-commissioned safety reviews examined these concerns and concluded that the experiments at the LHC present no danger and that there is no reason for concern,[156][157][158] a conclusion expressly endorsed by the American Physical Society.[159]

text: The reports also noted that the physical conditions and collision events that exist in the LHC and similar experiments occur naturally and routinely in the universe without hazardous consequences,[157] including ultra-high-energy cosmic rays observed to impact Earth with energies far higher than those in any man-made collider.

text: Popular culture[edit]

text: The Large Hadron Collider gained a considerable amount of attention from outside the scientific community and its progress is followed by most popular science media. The LHC has also inspired works of fiction including novels, TV series, video games and films.

text: CERN employee Katherine McAlpine's "Large Hadron Rap"[160] surpassed 7 million YouTube views.[161][162] The band Les Horribles Cernettes was founded by women from CERN. The name was chosen so to have the same initials as the LHC.[163][164]

text: National Geographic Channel's World's Toughest Fixes, Season 2 (2010), Episode 6 "Atom Smasher" features the replacement of the last superconducting magnet section in the repair of the collider after the 2008 quench incident. The episode includes actual footage from the repair facility to the inside of the collider, and explanations of the function, engineering, and purpose of the LHC.[165]

text: The Large Hadron Collider was the focus of the 2012 student film Decay, with the movie being filmed on location in CERN's maintenance tunnels.[166]

text: The feature documentary Particle Fever follows the experimental physicists at CERN who run the experiments, as well as the theoretical physicists who attempt to provide a conceptual framework for the LHC's results. It won the Sheffield International Doc/Fest in 2013.

text: Fiction[edit]

text: The novel Angels & Demons, by Dan Brown, involves antimatter created at the LHC to be used in a weapon against the Vatican. In response, CERN published a "Fact or Fiction?" page discussing the accuracy of the book's portrayal of the LHC, CERN, and particle physics in general.[167] The movie version of the book has footage filmed on-site at one of the experiments at the LHC; the director, Ron Howard, met with CERN experts in an effort to make the science in the story more accurate.[168]

text: In the visual novel/manga/anime-series "Steins;Gate", the primary antagonist controls a global research organization called SERN, the name of which is a deliberate misspelling of CERN. In the series SERN designs a particle accelerator and uses the miniature black holes created from experiments to master time travel and take over the world.

text: The novel FlashForward, by Robert J. Sawyer, involves the search for the Higgs boson at the LHC. CERN published a "Science and Fiction" page interviewing Sawyer and physicists about the book and the TV series based on it.[169]


document_title: Make love, not war

question_text: who came up with the phrase make love not war

text: Make love, not war

text: Make love, not war is an anti-war slogan commonly associated with the American counterculture of the 1960s. It was used primarily by those who were opposed to the Vietnam War, but has been invoked in other anti-war contexts since.[1][2] The "make love" part of the slogan often referred to the practice of free love that was growing among the American youth who denounced marriage as a tool for those who supported war and favored the traditional capitalist culture.[3]

text: The phrase's origins are unclear; Gershon Legman claimed to be the inventor of the phrase,[4][5] so did American singer Rod McKuen,[6] and some[who?] credit artist, social activist, folk figure, and sometime United States Presidential candidate under the Nudist Party on the Hippie 'Love Ticket' Louis Abolafia.[citation needed] Radical activists Penelope and Franklin Rosemont and Tor Faegre helped to popularize the phrase by printing thousands of "Make Love, Not War" buttons at the Solidarity Bookshop in Chicago, Illinois and distributing them at the Mother's Day Peace March in 1965. They were the first to print the slogan.[7] In April 1965, at a Vietnam demonstration in Eugene, Oregon, Diane Newell Meyer, then a senior at the University of Oregon, pinned a handwritten note on her sweater reading "Let's make love, not war", thus marking the beginning of the popularity of this phrase. A picture of Meyer wearing the slogan was printed in the Eugene Register-Guard and then a related article turned up in the New York Times on May 9, 1965.

text: When the slogan was used in California in 1967, then Governor Ronald Reagan joked to protesters "Those guys [the protesters] look like they can't make either of both".[8]

text: In popular culture[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2012) (Learn how and when to remove this template message)

text:
The slogan was featured in two 1973 songs: John Lennon's "Mind Games" and Bob Marley's 1973 song "No More Trouble." It was the inspiration for a book by David Allyn: Make Love, Not War: The Sexual Revolution: An Unfettered History. In the movie Field of Dreams, fictional character Terence Mann is credited with coining the phrase.
The character of 'Pop', in the futuristic Queen musical play We Will Rock You, shouts "Make love, not war!" as he is brainwashed at the start of the show, which leads into the stage performance of 'Radio Ga Ga'.

text: On the DEC PDP-10, typing the command "make love" would result in the response "not war?" This action was copied on some older versions of UNIX. Some recent operating systems have brought the easter egg back, such as FreeBSD 7.0; as of /src/usr.bin/make/job.c version 1.126.2.1 if you type "make love," the answer you will get is "Not war."