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Observation of $J / ψ p$ Resonances Consistent with Pentaquark States in $Λ_{b}^{0} \to J / ψ K^{-} p$ Decays

R. Aaij³⁸, B. Adeva³⁷, M. Adinolfi⁴⁶, A. Affolder⁵², Z. Ajaltouni⁵, S. Akar⁶, J. Albrecht⁹, F. Alessio³⁸, M. Alexander⁵¹ et al. (LHCb Collaboration)

M. Alexander⁵¹, S. Ali⁴¹, G. Alkhazov³⁰, P. Alvarez Cartelle⁵³, A. A. Alves, Jr.⁵⁷, S. Amato², S. Amerio²², Y. Amhis⁷, L. An³, L. Anderlini¹⁷, J. Anderson⁴⁰, G. Andreassi³⁹, M. Andreotti^16,f, J. E. Andrews⁵⁸, R. B. Appleby⁵⁴, O. Aquines Gutierrez¹⁰, F. Archilli³⁸, P. d’Argent¹¹, A. Artamonov³⁵, M. Artuso⁵⁹, E. Aslanides⁶, G. Auriemma^25,m, M. Baalouch⁵, S. Bachmann¹¹, J. J. Back⁴⁸, A. Badalov³⁶, C. Baesso⁶⁰, W. Baldini^16,38, R. J. Barlow⁵⁴, C. Barschel³⁸, S. Barsuk⁷, W. Barter³⁸, V. Batozskaya²⁸, V. Battista³⁹, A. Bay³⁹, L. Beaucourt⁴, J. Beddow⁵¹, F. Bedeschi²³, I. Bediaga¹, L. J. Bel⁴¹, V. Bellee³⁹, N. Belloli²⁰, I. Belyaev³¹, E. Ben-Haim⁸, G. Bencivenni¹⁸, S. Benson³⁸, J. Benton⁴⁶, A. Berezhnoy³², R. Bernet⁴⁰, A. Bertolin²², M.-O. Bettler³⁸, M. van Beuzekom⁴¹, A. Bien¹¹, S. Bifani⁴⁵, P. Billoir⁸, T. Bird⁵⁴, A. Birnkraut⁹, A. Bizzeti^17,h, T. Blake⁴⁸, F. Blanc³⁹, J. Blouw¹⁰, S. Blusk⁵⁹, V. Bocci²⁵, A. Bondar³⁴, N. Bondar^30,38, W. Bonivento¹⁵, S. Borghi⁵⁴, M. Borsato⁷, T. J. V. Bowcock⁵², E. Bowen⁴⁰, C. Bozzi¹⁶, S. Braun¹¹, M. Britsch¹⁰, T. Britton⁵⁹, J. Brodzicka⁵⁴, N. H. Brook⁴⁶, A. Bursche⁴⁰, J. Buytaert³⁸, S. Cadeddu¹⁵, R. Calabrese^16,f, M. Calvi^20,j, M. Calvo Gomez^36,o, P. Campana¹⁸, D. Campora Perez³⁸, L. Capriotti⁵⁴, A. Carbone^14,d, G. Carboni^24,k, R. Cardinale^19,i, A. Cardini¹⁵, P. Carniti²⁰, L. Carson⁵⁰, K. Carvalho Akiba^2,38, G. Casse⁵², L. Cassina^20,j, L. Castillo Garcia³⁸, M. Cattaneo³⁸, Ch. Cauet⁹, G. Cavallero¹⁹, R. Cenci^23,s, M. Charles⁸, Ph. Charpentier³⁸, M. Chefdeville⁴, S. Chen⁵⁴, S.-F. Cheung⁵⁵, N. Chiapolini⁴⁰, M. Chrzaszcz⁴⁰, X. Cid Vidal³⁸, G. Ciezarek⁴¹, P. E. L. Clarke⁵⁰, M. Clemencic³⁸, H. V. Cliff⁴⁷, J. Closier³⁸, V. Coco³⁸, J. Cogan⁶, E. Cogneras⁵, V. Cogoni^15,e, L. Cojocariu²⁹, G. Collazuol²², P. Collins³⁸, A. Comerma-Montells¹¹, A. Contu^15,38, A. Cook⁴⁶, M. Coombes⁴⁶, S. Coquereau⁸, G. Corti³⁸, M. Corvo^16,f, B. Couturier³⁸, G. A. Cowan⁵⁰, D. C. Craik⁴⁸, A. Crocombe⁴⁸, M. Cruz Torres⁶⁰, S. Cunliffe⁵³, R. Currie⁵³, C. D’Ambrosio³⁸, E. Dall’Occo⁴¹, J. Dalseno⁴⁶, P. N. Y. David⁴¹, A. Davis⁵⁷, K. De Bruyn⁴¹, S. De Capua⁵⁴, M. De Cian¹¹, J. M. De Miranda¹, L. De Paula², P. De Simone¹⁸, C.-T. Dean⁵¹, D. Decamp⁴, M. Deckenhoff⁹, L. Del Buono⁸, N. Déléage⁴, M. Demmer⁹, D. Derkach⁵⁵, O. Deschamps⁵, F. Dettori³⁸, B. Dey²¹, A. Di Canto³⁸, F. Di Ruscio²⁴, H. Dijkstra³⁸, S. Donleavy⁵², F. Dordei¹¹, M. Dorigo³⁹, A. Dosil Suárez³⁷, D. Dossett⁴⁸, A. Dovbnya⁴³, K. Dreimanis⁵², L. Dufour⁴¹, G. Dujany⁵⁴, F. Dupertuis³⁹, P. Durante³⁸, R. Dzhelyadin³⁵, A. Dziurda²⁶, A. Dzyuba³⁰, S. Easo^49,38, U. Egede⁵³, V. Egorychev³¹, S. Eidelman³⁴, S. Eisenhardt⁵⁰, U. Eitschberger⁹, R. Ekelhof⁹, L. Eklund⁵¹, I. El Rifai⁵, Ch. Elsasser⁴⁰, S. Ely⁵⁹, S. Esen¹¹, H. M. Evans⁴⁷, T. Evans⁵⁵, A. Falabella¹⁴, C. Färber³⁸, N. Farley⁴⁵, S. Farry⁵², R. Fay⁵², D. Ferguson⁵⁰, V. Fernandez Albor³⁷, F. Ferrari¹⁴, F. Ferreira Rodrigues¹, M. Ferro-Luzzi³⁸, S. Filippov³³, M. Fiore^16,38,f, M. Fiorini^16,f, M. Firlej²⁷, C. Fitzpatrick³⁹, T. Fiutowski²⁷, K. Fohl³⁸, P. Fol⁵³, M. Fontana¹⁵, F. Fontanelli^19,i, R. Forty³⁸, O. Francisco², M. Frank³⁸, C. Frei³⁸, M. Frosini¹⁷, J. Fu²¹, E. Furfaro^24,k, A. Gallas Torreira³⁷, D. Galli^14,d, S. Gallorini^22,38, S. Gambetta⁵⁰, M. Gandelman², P. Gandini⁵⁵, Y. Gao³, J. García Pardiñas³⁷, J. Garra Tico⁴⁷, L. Garrido³⁶, D. Gascon³⁶, C. Gaspar³⁸, R. Gauld⁵⁵, L. Gavardi⁹, G. Gazzoni⁵, A. Geraci^21,u, D. Gerick¹¹, E. Gersabeck¹¹, M. Gersabeck⁵⁴, T. Gershon⁴⁸, Ph. Ghez⁴, A. Gianelle²², S. Gianì³⁹, V. Gibson⁴⁷, O. G. Girard³⁹, L. Giubega²⁹, V. V. Gligorov³⁸, C. Göbel⁶⁰, D. Golubkov³¹, A. Golutvin^53,31,38, A. Gomes^1,a, C. Gotti^20,j, M. Grabalosa Gándara⁵, R. Graciani Diaz³⁶, L. A. Granado Cardoso³⁸, E. Graugés³⁶, E. Graverini⁴⁰, G. Graziani¹⁷, A. Grecu²⁹, E. Greening⁵⁵, S. Gregson⁴⁷, P. Griffith⁴⁵, L. Grillo¹¹, O. Grünberg⁶³, B. Gui⁵⁹, E. Gushchin³³, Yu. Guz^35,38, T. Gys³⁸, T. Hadavizadeh⁵⁵, C. Hadjivasiliou⁵⁹, G. Haefeli³⁹, C. Haen³⁸, S. C. Haines⁴⁷, S. Hall⁵³, B. Hamilton⁵⁸, X. Han¹¹, S. Hansmann-Menzemer¹¹, N. Harnew⁵⁵, S. T. Harnew⁴⁶, J. Harrison⁵⁴, J. He³⁸, T. Head³⁹, V. Heijne⁴¹, K. Hennessy⁵², P. Henrard⁵, L. Henry⁸, J. A. Hernando Morata³⁷, E. van Herwijnen³⁸, M. Heß⁶³, A. Hicheur², D. Hill⁵⁵, M. Hoballah⁵, C. Hombach⁵⁴, W. Hulsbergen⁴¹, T. Humair⁵³, N. Hussain⁵⁵, D. Hutchcroft⁵², D. Hynds⁵¹, M. Idzik²⁷, P. Ilten⁵⁶, R. Jacobsson³⁸, A. Jaeger¹¹, J. Jalocha⁵⁵, E. Jans⁴¹, A. Jawahery⁵⁸, F. Jing³, M. John⁵⁵, D. Johnson³⁸, C. R. Jones⁴⁷, C. Joram³⁸, B. Jost³⁸, N. Jurik⁵⁹, S. Kandybei⁴³, W. Kanso⁶, M. Karacson³⁸, T. M. Karbach^38,†, S. Karodia⁵¹, M. Kecke¹¹, M. Kelsey⁵⁹, I. R. Kenyon⁴⁵, M. Kenzie³⁸, T. Ketel⁴², B. Khanji^20,38,j, C. Khurewathanakul³⁹, S. Klaver⁵⁴, K. Klimaszewski²⁸, O. Kochebina⁷, M. Kolpin¹¹, I. Komarov³⁹, R. F. Koopman⁴², P. Koppenburg^41,38, M. Kozeiha⁵, L. Kravchuk³³, K. Kreplin¹¹, M. Kreps⁴⁸, G. Krocker¹¹, P. Krokovny³⁴, F. Kruse⁹, W. Krzemien²⁸, W. Kucewicz^26,n, M. Kucharczyk²⁶, V. Kudryavtsev³⁴, A. K. Kuonen³⁹, K. Kurek²⁸, T. Kvaratskheliya³¹, D. Lacarrere³⁸, G. Lafferty⁵⁴, A. Lai¹⁵, D. Lambert⁵⁰, G. Lanfranchi¹⁸, C. Langenbruch⁴⁸, B. Langhans³⁸, T. Latham⁴⁸, C. Lazzeroni⁴⁵, R. Le Gac⁶, J. van Leerdam⁴¹, J.-P. Lees⁴, R. Lefèvre⁵, A. Leflat^32,38, J. Lefrançois⁷, O. Leroy⁶, T. Lesiak²⁶, B. Leverington¹¹, Y. Li⁷, T. Likhomanenko^65,64, M. Liles⁵², R. Lindner³⁸, C. Linn³⁸, F. Lionetto⁴⁰, B. Liu¹⁵, X. Liu³, D. Loh⁴⁸, I. Longstaff⁵¹, J. H. Lopes², D. Lucchesi^22,q, M. Lucio Martinez³⁷, H. Luo⁵⁰, A. Lupato²², E. Luppi^16,f, O. Lupton⁵⁵, N. Lusardi²¹, A. Lusiani²³, F. Machefert⁷, F. Maciuc²⁹, O. Maev³⁰, K. Maguire⁵⁴, S. Malde⁵⁵, A. Malinin⁶⁴, G. Manca⁷, G. Mancinelli⁶, P. Manning⁵⁹, A. Mapelli³⁸, J. Maratas⁵, J. F. Marchand⁴, U. Marconi¹⁴, C. Marin Benito³⁶, P. Marino^23,38,s, J. Marks¹¹, G. Martellotti²⁵, M. Martin⁶, M. Martinelli³⁹, D. Martinez Santos³⁷, F. Martinez Vidal⁶⁶, D. Martins Tostes², A. Massafferri¹, R. Matev³⁸, A. Mathad⁴⁸, Z. Mathe³⁸, C. Matteuzzi²⁰, A. Mauri⁴⁰, B. Maurin³⁹, A. Mazurov⁴⁵, M. McCann⁵³, J. McCarthy⁴⁵, A. McNab⁵⁴, R. McNulty¹², B. Meadows⁵⁷, F. Meier⁹, M. Meissner¹¹, D. Melnychuk²⁸, M. Merk⁴¹, D. A. Milanes⁶², M.-N. Minard⁴, D. S. Mitzel¹¹, J. Molina Rodriguez⁶⁰, I. A. Monroy⁶², S. Monteil⁵, M. Morandin²², P. Morawski²⁷, A. Mordà⁶, M. J. Morello^23,s, J. Moron²⁷, A. B. Morris⁵⁰, R. Mountain⁵⁹, F. Muheim⁵⁰, J. Müller⁹, K. Müller⁴⁰, V. Müller⁹, M. Mussini¹⁴, B. Muster³⁹, P. Naik⁴⁶, T. Nakada³⁹, R. Nandakumar⁴⁹, A. Nandi⁵⁵, I. Nasteva², M. Needham⁵⁰, N. Neri²¹, S. Neubert¹¹, N. Neufeld³⁸, M. Neuner¹¹, A. D. Nguyen³⁹, T. D. Nguyen³⁹, C. Nguyen-Mau^39,p, V. Niess⁵, R. Niet⁹, N. Nikitin³², T. Nikodem¹¹, D. Ninci²³, A. Novoselov³⁵, D. P. O’Hanlon⁴⁸, A. Oblakowska-Mucha²⁷, V. Obraztsov³⁵, S. Ogilvy⁵¹, O. Okhrimenko⁴⁴, R. Oldeman^15,e, C. J. G. Onderwater⁶⁷, B. Osorio Rodrigues¹, J. M. Otalora Goicochea², A. Otto³⁸, P. Owen⁵³, A. Oyanguren⁶⁶, A. Palano^13,c, F. Palombo^21,t, M. Palutan¹⁸, J. Panman³⁸, A. Papanestis⁴⁹, M. Pappagallo⁵¹, L. L. Pappalardo^16,f, C. Pappenheimer⁵⁷, C. Parkes⁵⁴, G. Passaleva¹⁷, G. D. Patel⁵², M. Patel⁵³, C. Patrignani^19,i, A. Pearce^54,49, A. Pellegrino⁴¹, G. Penso^25,l, M. Pepe Altarelli³⁸, S. Perazzini^14,d, P. Perret⁵, L. Pescatore⁴⁵, K. Petridis⁴⁶, A. Petrolini^19,i, M. Petruzzo²¹, E. Picatoste Olloqui³⁶, B. Pietrzyk⁴, T. Pilař⁴⁸, D. Pinci²⁵, A. Pistone¹⁹, A. Piucci¹¹, S. Playfer⁵⁰, M. Plo Casasus³⁷, T. Poikela³⁸, F. Polci⁸, A. Poluektov^48,34, I. Polyakov³¹, E. Polycarpo², A. Popov³⁵, D. Popov^10,38, B. Popovici²⁹, C. Potterat², E. Price⁴⁶, J. D. Price⁵², J. Prisciandaro³⁹, A. Pritchard⁵², C. Prouve⁴⁶, V. Pugatch⁴⁴, A. Puig Navarro³⁹, G. Punzi^23,r, W. Qian⁴, R. Quagliani^7,46, B. Rachwal²⁶, J. H. Rademacker⁴⁶, M. Rama²³, M. S. Rangel², I. Raniuk⁴³, N. Rauschmayr³⁸, G. Raven⁴², F. Redi⁵³, S. Reichert⁵⁴, M. M. Reid⁴⁸, A. C. dos Reis¹, S. Ricciardi⁴⁹, S. Richards⁴⁶, M. Rihl³⁸, K. Rinnert⁵², V. Rives Molina³⁶, P. Robbe^7,38, A. B. Rodrigues¹, E. Rodrigues⁵⁴, J. A. Rodriguez Lopez⁶², P. Rodriguez Perez⁵⁴, S. Roiser³⁸, V. Romanovsky³⁵, A. Romero Vidal³⁷, J. W. Ronayne¹², M. Rotondo²², J. Rouvinet³⁹, T. Ruf³⁸, P. Ruiz Valls⁶⁶, J. J. Saborido Silva³⁷, N. Sagidova³⁰, P. Sail⁵¹, B. Saitta^15,e, V. Salustino Guimaraes², C. Sanchez Mayordomo⁶⁶, B. Sanmartin Sedes³⁷, R. Santacesaria²⁵, C. Santamarina Rios³⁷, M. Santimaria¹⁸, E. Santovetti^24,k, A. Sarti^18,l, C. Satriano^25,m, A. Satta²⁴, D. M. Saunders⁴⁶, D. Savrina^31,32, M. Schiller³⁸, H. Schindler³⁸, M. Schlupp⁹, M. Schmelling¹⁰, T. Schmelzer⁹, B. Schmidt³⁸, O. Schneider³⁹, A. Schopper³⁸, M. Schubiger³⁹, M.-H. Schune⁷, R. Schwemmer³⁸, B. Sciascia¹⁸, A. Sciubba^25,l, A. Semennikov³¹, N. Serra⁴⁰, J. Serrano⁶, L. Sestini²², P. Seyfert²⁰, M. Shapkin³⁵, I. Shapoval^16,43,f, Y. Shcheglov³⁰, T. Shears⁵², L. Shekhtman³⁴, V. Shevchenko⁶⁴, A. Shires⁹, B. G. Siddi¹⁶, R. Silva Coutinho⁴⁸, G. Simi²², M. Sirendi⁴⁷, N. Skidmore⁴⁶, I. Skillicorn⁵¹, T. Skwarnicki⁵⁹, E. Smith^55,49, E. Smith⁵³, I. T. Smith⁵⁰, J. Smith⁴⁷, M. Smith⁵⁴, H. Snoek⁴¹, M. D. Sokoloff^57,38, F. J. P. Soler⁵¹, F. Soomro³⁹, D. Souza⁴⁶, B. Souza De Paula², B. Spaan⁹, P. Spradlin⁵¹, S. Sridharan³⁸, F. Stagni³⁸, M. Stahl¹¹, S. Stahl³⁸, S. Stefkova⁵³, O. Steinkamp⁴⁰, O. Stenyakin³⁵, S. Stevenson⁵⁵, S. Stoica²⁹, S. Stone⁵⁹, B. Storaci⁴⁰, S. Stracka^23,s, M. Straticiuc²⁹, U. Straumann⁴⁰, L. Sun⁵⁷, W. Sutcliffe⁵³, K. Swientek²⁷, S. Swientek⁹, V. Syropoulos⁴², M. Szczekowski²⁸, P. Szczypka^39,38, T. Szumlak²⁷, S. T’Jampens⁴, A. Tayduganov⁶, T. Tekampe⁹, M. Teklishyn⁷, G. Tellarini^16,f, F. Teubert³⁸, C. Thomas⁵⁵, E. Thomas³⁸, J. van Tilburg⁴¹, V. Tisserand⁴, M. Tobin³⁹, J. Todd⁵⁷, S. Tolk⁴², L. Tomassetti^16,f, D. Tonelli³⁸, S. Topp-Joergensen⁵⁵, N. Torr⁵⁵, E. Tournefier⁴, S. Tourneur³⁹, K. Trabelsi³⁹, M. T. Tran³⁹, M. Tresch⁴⁰, A. Trisovic³⁸, A. Tsaregorodtsev⁶, P. Tsopelas⁴¹, N. Tuning^41,38, A. Ukleja²⁸, A. Ustyuzhanin^65,64, U. Uwer¹¹, C. Vacca^15,e, V. Vagnoni¹⁴, G. Valenti¹⁴, A. Vallier⁷, R. Vazquez Gomez¹⁸, P. Vazquez Regueiro³⁷, C. Vázquez Sierra³⁷, S. Vecchi¹⁶, J. J. Velthuis⁴⁶, M. Veltri^17,g, G. Veneziano³⁹, M. Vesterinen¹¹, B. Viaud⁷, D. Vieira², M. Vieites Diaz³⁷, X. Vilasis-Cardona^36,o, A. Vollhardt⁴⁰, D. Volyanskyy¹⁰, D. Voong⁴⁶, A. Vorobyev³⁰, V. Vorobyev³⁴, C. Voß⁶³, J. A. de Vries⁴¹, R. Waldi⁶³, C. Wallace⁴⁸, R. Wallace¹², J. Walsh²³, S. Wandernoth¹¹, J. Wang⁵⁹, D. R. Ward⁴⁷, N. K. Watson⁴⁵, D. Websdale⁵³, A. Weiden⁴⁰, M. Whitehead⁴⁸, G. Wilkinson^55,38, M. Wilkinson⁵⁹, M. Williams³⁸, M. P. Williams⁴⁵, M. Williams⁵⁶, T. Williams⁴⁵, F. F. Wilson⁴⁹, J. Wimberley⁵⁸, J. Wishahi⁹, W. Wislicki²⁸, M. Witek²⁶, G. Wormser⁷, S. A. Wotton⁴⁷, S. Wright⁴⁷, K. Wyllie³⁸, Y. Xie⁶¹, Z. Xu³⁹, Z. Yang³, J. Yu⁶¹, X. Yuan³⁴, O. Yushchenko³⁵, M. Zangoli¹⁴, M. Zavertyaev^10,b, L. Zhang³, Y. Zhang³, A. Zhelezov¹¹, A. Zhokhov³¹, L. Zhong³, and S. Zucchelli¹⁴ (LHCb Collaboration)

¹Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil
²Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
³Center for High Energy Physics, Tsinghua University, Beijing, China
⁴LAPP, Université Savoie Mont-Blanc, CNRS/IN2P3, Annecy-Le-Vieux, France
⁵Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand, France
⁶CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
⁷LAL, Université Paris-Sud, CNRS/IN2P3, Orsay, France
⁸LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris, France
⁹Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
¹⁰Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany
¹¹Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
¹²School of Physics, University College Dublin, Dublin, Ireland
¹³Sezione INFN di Bari, Bari, Italy
¹⁴Sezione INFN di Bologna, Bologna, Italy
¹⁵Sezione INFN di Cagliari, Cagliari, Italy
¹⁶Sezione INFN di Ferrara, Ferrara, Italy
¹⁷Sezione INFN di Firenze, Firenze, Italy
¹⁸Laboratori Nazionali dell’INFN di Frascati, Frascati, Italy
¹⁹Sezione INFN di Genova, Genova, Italy
²⁰Sezione INFN di Milano Bicocca, Milano, Italy
²¹Sezione INFN di Milano, Milano, Italy
²²Sezione INFN di Padova, Padova, Italy
²³Sezione INFN di Pisa, Pisa, Italy
²⁴Sezione INFN di Roma Tor Vergata, Roma, Italy
²⁵Sezione INFN di Roma La Sapienza, Roma, Italy
²⁶Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
²⁷AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland
²⁸National Center for Nuclear Research (NCBJ), Warsaw, Poland
²⁹Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania
³⁰Petersburg Nuclear Physics Institute (PNPI), Gatchina, Russia
³¹Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia
³²Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia
³³Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN), Moscow, Russia
³⁴Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University, Novosibirsk, Russia
³⁵Institute for High Energy Physics (IHEP), Protvino, Russia
³⁶Universitat de Barcelona, Barcelona, Spain
³⁷Universidad de Santiago de Compostela, Santiago de Compostela, Spain
³⁸European Organization for Nuclear Research (CERN), Geneva, Switzerland
³⁹Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
⁴⁰Physik-Institut, Universität Zürich, Zürich, Switzerland
⁴¹Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands
⁴²Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, The Netherlands
⁴³NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine
⁴⁴Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine
⁴⁵University of Birmingham, Birmingham, United Kingdom
⁴⁶H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom
⁴⁷Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
⁴⁸Department of Physics, University of Warwick, Coventry, United Kingdom
⁴⁹STFC Rutherford Appleton Laboratory, Didcot, United Kingdom
⁵⁰School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
⁵¹School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
⁵²Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom
⁵³Imperial College London, London, United Kingdom
⁵⁴School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
⁵⁵Department of Physics, University of Oxford, Oxford, United Kingdom
⁵⁶Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
⁵⁷University of Cincinnati, Cincinnati, Ohio, USA
⁵⁸University of Maryland, College Park, Maryland, USA
⁵⁹Syracuse University, Syracuse, New York, USA
⁶⁰Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil)
⁶¹Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China)
⁶²Departamento de Fisica, Universidad Nacional de Colombia, Bogota, Colombia (associated with LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris, France)
⁶³Institut für Physik, Universität Rostock, Rostock, Germany (associated with Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany)
⁶⁴National Research Centre Kurchatov Institute, Moscow, Russia (associated with Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia)
⁶⁵Yandex School of Data Analysis, Moscow, Russia (associated with Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia)
⁶⁶Instituto de Fisica Corpuscular (IFIC), Universitat de Valencia-CSIC, Valencia, Spain (associated with Universitat de Barcelona, Barcelona, Spain)
⁶⁷Van Swinderen Institute, University of Groningen, Groningen, The Netherlands (associated with Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands)

^*Full author list given at end of the article.
^†Deceased.
^aAlso at Universidade Federal do Triângulo Mineiro (UFTM), Uberaba-MG, Brazil.
^bAlso at P. N. Lebedev Physical Institute, Russian Academy of Science (LPI RAS), Moscow, Russia.
^cAlso at Università di Bari, Bari, Italy.
^dAlso at Università di Bologna, Bologna, Italy.
^eAlso at Università di Cagliari, Cagliari, Italy.
^fAlso at Università di Ferrara, Ferrara, Italy.
^gAlso at Università di Urbino, Urbino, Italy.
^hAlso at Università di Modena e Reggio Emilia, Modena, Italy.
ⁱAlso at Università di Genova, Genova, Italy.
^jAlso at Università di Milano Bicocca, Milano, Italy.
^kAlso at Università di Roma Tor Vergata, Roma, Italy.
^lAlso at Università di Roma La Sapienza, Roma, Italy.
^mAlso at Università della Basilicata, Potenza, Italy.
ⁿAlso at AGH - University of Science and Technology, Faculty of Computer Science, Electronics and Telecommunications, Kraków, Poland.
^oAlso at LIFAELS, La Salle, Universitat Ramon Llull, Barcelona, Spain.
^pAlso at Hanoi University of Science, Hanoi, Vietnam.
^qAlso at Università di Padova, Padova, Italy.
^rAlso at Università di Pisa, Pisa, Italy.
^sAlso at Scuola Normale Superiore, Pisa, Italy.
^tAlso at Università degli Studi di Milano, Milano, Italy.
^uAlso at Politecnico di Milano, Milano, Italy.

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Phys. Rev. Lett. 115, 072001 – Published 12 August, 2015

DOI: https://doi.org/10.1103/PhysRevLett.115.072001

Abstract

Observations of exotic structures in the $J / ψ p$ channel, which we refer to as charmonium-pentaquark states, in $Λ_{b}^{0} \to J / ψ K^{-} p$ decays are presented. The data sample corresponds to an integrated luminosity of $3 {fb}^{- 1}$ acquired with the LHCb detector from 7 and 8 TeV $p p$ collisions. An amplitude analysis of the three-body final state reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the $J / ψ p$ mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of $4380 \pm 8 \pm 29 MeV$ and a width of $205 \pm 18 \pm 86 MeV$ , while the second is narrower, with a mass of $4449.8 \pm 1.7 \pm 2.5 MeV$ and a width of $39 \pm 5 \pm 19 MeV$ . The preferred $J^{P}$ assignments are of opposite parity, with one state having spin $3 / 2$ and the other $5 / 2$ .

Viewpoint

Elusive Pentaquark Comes into View

Published 12 August, 2015

A new type of particle containing five quarks has been observed by the LHCb experiment.

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Phys. Rev. Lett. 115, 072001– Published 12 August, 2015

Vol. 115, Iss. 7 — 14 August 2015

Received 13 July 2015

DOI: https://doi.org/10.1103/PhysRevLett.115.072001

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Observation of $J / ψ p$ Resonances Consistent with Pentaquark States in $Λ_{b}^{0} \to J / ψ K^{-} p$ Decays

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Elusive Pentaquark Comes into View

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Observation of J/ψp Resonances Consistent with Pentaquark States in Λb0→J/ψK−p Decays

Abstract

Viewpoint

Elusive Pentaquark Comes into View

Article Text

Supplemental Material

References (45)

Observation of $J / ψ p$ Resonances Consistent with Pentaquark States in $Λ_{b}^{0} \to J / ψ K^{-} p$ Decays