Observation of ExcitedΛb0Baryons

R Aaij,M Artuso,H Schindler,F Stagni,J Garofoli,P Seyfert,G Martellotti,M Gersabeck,A Affolder,T Szumlak,L Garrido,L Shekhtman,M Clemencic,E Ben-Haim,T Hampson,G Corti,M Schlupp,A Bursche,R Silva Coutinho,I Videau,B Rakotomiaramanana,C Coca,G Graziani,A Ukleja,C Adrover,J Mccarthy,G Lanfranchi,B Popovici,A Sarti,P Morawski,E Teodorescu,M Zavertyaev,C J Parkinson,A Gomes,C Hadjivasiliou,B Gui,G Krocker,T J V Bowcock,O Deschamps,E Van Herwijnen,B Sciascia,M Needham,E Hicks,M De Cian,B Saitta,C Bauer,I Bediaga,T Pilař,F Eisele,D Golubkov,M.-N Minard,S Furcas,G Raven,D Vieira,M Gandelman,F Kruse,J Serrano,S Swientek,J Molina Rodriguez,G Ciezarek,M Pappagallo,A Falabella,G N Patrick,A Keune,G Manca,J H Rademacker,R Lefèvre,J Wicht,A Bizzeti,S Oggero,P F Harrison,J Lefrançois,A Massafferri,A Cardini,I V Machikhiliyan,C Bozzi,Y Amhis,O Grünberg,V Egorychev,P Szczypka,S Stoica,A Tsaregorodtsev,D R Ward,T Latham,J Imong,D Hynds,A Bondar,T Gys,T Hartmann,M Alexander,D Van Eijk,A Shires,C Thomas,A Grecu,R Wallace,T Britton,P Hunt,M Cattaneo,S Belogurov,C Blanks,S Gregson,M Sannino,M Matveev,C Langenbruch,W Hulsbergen,M Britsch,R Nandakumar,J Mylroie-Smith,S Farry,M Schmelling,S Topp-Joergensen,M Frank,S Vecchi,J Wishahi,L A Granado Cardoso,D Voong,G Bencivenni,J Blouw,J Rouvinet,F F Wilson,S Blusk,M Martinelli,K De Bruyn,F Maciuc,M Smith,S Borghi,F Machefert,A Vorobyev,F Dupertuis,E Lopez Asamar,A Carbone,M Lieng,J Buytaert,A D Webber,D Pinci,Ph Ghez,J Merkel,E Greening,M Seco,P Gandini,E Picatoste Olloqui,N Harnew,R Schwemmer,C D’Ambrosio,M Sapunov,J Anderson,D Savrina,N Torr,S Benson,J Luisier,A Bobrov,A Powell,N Neufeld,S Easo,M Coombes,B K Pal,I Mous,F Fontanelli,V Shevchenko,V Pugatch,D Gascon,R Mcnulty,K Rinnert,A Vollhardt,T Huse,A Pellegrino,S Filippov,P Koppenburg,S Wandernoth,V Balagura,H Dijkstra,R Le Gac,C Haen,D Souza,S Donleavy,I Belyaev,J Van Den Brand,P Shatalov,Ph Charpentier,B Storaci,C Matteuzzi,N Tuning,S Ricciardi,I R Kenyon,R W Lambert,A Sparkes,M Perrin-Terrin,D Dossett,B Sanmartin Sedes,P Henrard,A D Nguyen,D Brett,R Lindner,C Frei,M Kaballo,V Kudryavtsev,T Ketel,F Jansen,O Yushchenko,R Young,A Palano,P Collins,N K Watson,A Pérez-Calero Yzquierdo,S Tolk,P Owen,G J Rogers,C Nguyen-Mau,A Mazurov,K Ciba,V Obraztsov,B Viaud,S Tourneur,S Roiser,G Alkhazov,Z Ajaltouni,G Auriemma,O Aquines Gutierrez,T Nikodem,V K Subbiah,R J Barlow,D Elsby,J Dickens,S Schleich,Th Bauer,C R Jones,S Kandybei,M P Williams,J J Back,F Dettori,F Dordei,S Ali,R Graciani Diaz,S Wright,M S Rangel,S Cadeddu,A Kozlinskiy,V Bocci,S Hansmann-Menzemer,R M D Mamunur,B Schmidt,B Souza De Paula,B Jost,J M De Miranda,E Santovetti,T Kvaratskheliya,V Gibson,S Eisenhardt,S Eidelman,F Jing,P Ilten,C Farinelli,S Amato,S Stone,N Chiapolini,J Prisciandaro,L Li,R Currie,M Fontana,A C Dos Reis,E Gushchin,T Skwarnicki,S Monteil,D Galli,W Qian,F Polci,R Plackett,T Ruf,M Witek,R Santacesaria,D Moran,M Shapkin,A Büchler-Germann,A Petrolini,S Redford,Y Shcheglov,L Eklund,A Bay,R Gauld,V Fave,B Muryn,I Nasteva,F Alessio,Y Li,W C Zhang,F Muheim,S Bifani,D Popov,M Straticiuc,A Zhelezov,L Zhong,A Semennikov,I De Bonis,J J Saborido Silva,J Magnin,K Wyllie,C Parkes,G Valenti,M Vesterinen,K Kruzelecki,A Sciubba,W Bonivento,A Poluektov,N Gauvin,M Schiller,T M Karbach,F Soomro,C Färber,O Steinkamp,S C Haines,P E L Clarke,O Maev,E Tournefier,C Linn,A Contu,M Kucharczyk,G Mcgregor,J J Velthuis,A Phan,M Calvo Gomez,C Lazzeroni,B Pietrzyk,E Polycarpo,P Perret,M Patel,A Martens,T Blake,C Pavel-Nicorescu,L Carson,E Graugés,H Brown,E Jans,M Deckenhoff,V N La Thi,J Von Loeben,A Richards,N Serra,D Hutchcroft,D Volyanskyy,N Nikitin,H Degaudenzi,G Mancinelli,M John,F J P Soler,M Pepe Altarelli,R B Appleby,F Blanc,M Frosini,G Carboni,I Sepp,M Ubeda Garcia,J Bressieux,A Satta,J Van Tilburg,D A Roa Romero,N Mangiafave,N Sagidova,T Brambach,P Diniz Batista,P De Simone,A A Alves,G Fardell,V Romanovsky,K Sobczak,B Liu,Y M Kim,T Nakada,B Adeva,M Van Beuzekom,M Teklishyn,J Beddow,Y Xie,L De Paula,R Bernet,V Tisserand,N A Smith,N H Brook,Y Zhang,R Oldeman,R F Koopman,G D Patel,U Uwer,I Shapoval,S Stahl,H V Cliff,S De Capua,B Maynard,X Yuan,J Closier,P David,A Golutvin,G Wilkinson,O Leroy,C Patrignani,J Harrison,M Nicol,A Cook,G Sabatino,E Lanciotti,R Ekelhof,F Archilli,C Gaspar,H Ruiz,E Thomas,B Pie Valls,J Van Leerdam,V Coco,C Voß,M Palutan,D Johnson,F Zhang,A Leflat,V Vorobyev,R Forty,W Baldini,J Albrecht,S Perazzini,V Fernandez Albor,R Cardinale,R Dzhelyadin,M Grabalosa Gándara,L Kravchuk,C Salzmann,U Straumann,J H Lopes,G Liu,A Novoselov,I Komarov,R Mountain,V V Gligorov,I El Rifai,S T Harnew,S Ogilvy,I Burducea,T Gershon,A Bates,T Bird,K Müller,D Esperante Pereira,U Marconi,M Whitehead,R Vazquez Gomez,Y Gao,V Niess,D L Perego,D Websdale,S A Wotton,B Khanji,H Voss,U Egede,K Carvalho Akiba,G Haefeli,J Cogan,P Naik,A Dosil Suárez,O Kochebina,B Couturier,A Lai,F Teubert,Z Yang,W Barter,E Rodrigues,L Zhang,M T Tran,A Puig Navarro,G Casse,W Witzeling,G Penso,M Merk,A Schopper,F Domingo Bonal,C Göbel,P Alvarez Cartelle,A Zvyagin,J A Hernando Morata,R Märki,O Schneider,A Solomin,P Sail,M Calvi,A Dziurda,M Benayoun,P Jaton,Z Xing,O Okhrimenko,J Panman,K Hennessy,U Kerzel,R Santinelli,S Barsuk,G Passaleva,T Lesiak,M Szczekowski,E Maurice,P M Bjørnstad,A Dovbnya,C Satriano,G Polok,A Camboni,M Knecht,B Spaan,P Spradlin,O Callot,A Jaeger,A Papanestis,J Benton,A Comerma-Montells,D Lambert,F Xing,A Dzyuba,Ch Cauet,C Barschel,J M Otalora Goicochea,M Karacson,A Borgia,A Gallas Torreira,M Liles,J Wang,S T’Jampens,S Bachmann,M Charles,J He,P Campana,K Senderowska,A Mac Raighne,E Aslanides,X Cid Vidal,L Li Gioi,M Adinolfi,S Playfer,B Muster,L Del Buono,R Waldi,M Kreps,A Nomerotski,E Cogneras,M Veltri,M Tobin,C Potterat,K Belous,P Chen,S Malde,K Kreplin,P Robbe,J Marks,Yu Guz,I Raniuk,L Wiggers,J Keaveney,V Heijne,G Pessina,G A Cowan,C Deplano,E Smith,V Vagnoni,M M Reid,N Bondar,P Krokovny,A Adametz,C Fitzpatrick,M Orlandea,M Hoballah,J Palacios,R S Huston,T Shears,M Zangoli,R Jacobsson,P Schaack,D Wiedner,M Meissner,A Martín Sánchez,P Vázquez Regueiro ,P H Hopchev ,D Lacarrère ,C Santamarina Ríos ,M Hussein ,L M Garcia Martin ,J P Lees ,A Obłąkowska-Mucha ,B Jean‐Marie ,O De Aguiar Francisco ,F Ferreira Rodrigues ,E Pérez Trigo ,G D Lafferty ,М Королев ,M Chrząszcz ,M Savrié ,S L Wu ,D Martínez Santos ,M Roselló ,X Vilasis‐Cardona ,D C Craik ,Z Máthé ,M O Bettler ,A Bień ,M Pló Casasús ,D A Milanés ,Ch Elsässer ,J C Garnier ,N López-March ,J Garra Ticó ,P Rodríguez Pérez ,Hamish Gordon ,О Shevchenko ,C Abellán Beteta ,R Mureşan ,M H Schune ,А Артамонов ,M Ferro‐Luzzi ,H Lü ,Д Деркач ,J Višniakov ,D Décamp ,В Яковенко ,A Pazos Álvarez

doi:10.1103/physrevlett.109.172003

Abstract

Using pp collision data corresponding to 1.0 fb−1 integrated luminosity collected by the LHCb detector, two narrow states are observed in the Λb0π+π− spectrum with masses 5911.97±0.12(stat)±0.02(syst)±0.66(Λb0 mass) MeV/c2 and 5919.77±0.08(stat)±0.02(syst)±0.66(Λb0 mass) MeV/c2. The significances of the observations are 5.2 and 10.2 standard deviations, respectively. These states are interpreted as the orbitally excited Λb0 baryons, Λb*0(5912) and Λb*0(5920).Received 16 May 2012DOI:https://doi.org/10.1103/PhysRevLett.109.172003This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.© 2012 CERN, for the LHCb Collaboration

Highlights

The system of baryons containing a b quark remains largely unexplored, despite recent progress made at the experiments at the Tevatron
Of the triplets ÆÆb ;0 with spin J 1⁄4 1=2 and ÆÃbÆ;0 with J 1⁄4 3=2 predicted by theory, only the charged states ÆðbÃÞÆ have so far been observed via their decay to Ã0b%Æ final states [7,8]
Observation of ÃÃb0 states and measurement of their quantum numbers would provide a further confirmation of the validity of the quark model, and the precise measurement of their masses would test the applicability of various theoretical models used to describe the interaction of heavy quarks

Summary

Introduction

The system of baryons containing a b quark (beauty baryons) remains largely unexplored, despite recent progress made at the experiments at the Tevatron. A kinematic fit is applied that, in addition to all constraints described above for Ã0b candidates, constrains the two slow pion tracks to originate from the PV and the invariant mass of the Ã0b candidate to a fixed value of 5619:37 MeV=c2, which is a combination of the world average [18] and the LHCb measurement [26].

Results

Conclusion