Measurement of the fraction of Υ (1S) originating from χb(1P) decays in pp collisions at $ \sqrt{s}=7\,TeV $

B Storaci,N H Brook,S Blusk,B Sanmartin Sedes,E Rodrigues,D Brett,S Tolk,G Graziani,B Spaan,A Mac Raighne,B Jost,G Raven,S Topp-Joergensen,M Straticiuc,I Komarov,A D Webber,C Deplano,C Satriano,P M Bjørnstad,M Patel,B Muryn,M Karacson,A Novoselov,T Ruf,R Mountain,O Kochebina,T Lesiak,M Merk,A Golutvin,G J Rogers,H Brown,S Monteil,R S Huston,J Van Leerdam,M Seco,A Dosil Suárez,F Polci,S Schleich,M Shapkin,S Playfer,P Hunt,N Chiapolini,C Salzmann,J Von Loeben,F Dordei,E Teodorescu,P Szczypka,M Ubeda Garcia,J Blouw,U Straumann,E Lanciotti,D Vieira,E Picatoste Olloqui,G Manca,A Keune,J Luisier,A Palano,V Romanovsky,M Calvo Gomez,J Imong,R Wallace,N Gauvin,R Jacobsson,M Lieng,R B Appleby,E Tournefier,H Ruiz,M Gandelman,F Jansen,V Vorobyev,T Hartmann,F Soomro,J Mccarthy,I Sepp,B Gui,A Adametz,T Huse,A Satta,Yu Guz,S Filippov,L Kravchuk,S Hansmann-Menzemer,E Greening,T M Karbach,S A Wotton,G Auriemma,I Raniuk,L Wiggers,A Sparkes,T Bird,Y Zhang,T Pilař,M Needham,G Mancinelli,M Nicol,A Romero Vidal,B Muster,V N La Thi,J Mylroie-Smith,R F Koopman,G Fardell,G Alkhazov,A Tsaregorodtsev,A Zhelezov,M Matveev,J Anderson,A Artamonov,C Pavel-Nicorescu,D A Roa Romero,U Uwer,E Santovetti,R W Lambert,H Voss,B Rakotomiaramanana,A Dzyuba,A Phan,I El Rifai,M Teklishyn,D Hynds,Ph Ghez,N Torr,S Furcas,S Ali,S Kandybei,Th Bauer,M Knecht,G Penso,C Färber,X Cid Vidal,B Pietrzyk,T Hampson,R Mcnulty,S Ogilvy,T Brambach,T J V Bowcock,O Maev,F Xing,L Zhong,B Couturier,M Meissner,G Polok,Ch Cauet,F Muheim,A Sciubba,E Cogneras,A Cook,A Gallas Torreira,K Senderowska,B Popovici,C Linn,J Marks,G Bencivenni,C Fitzpatrick,S Malde,A Büchler-Germann,M Zangoli,P Collins,N Tuning,A Lai,B Schmidt,C Potterat,A C Dos Reis,J J Back,V Obraztsov,J Serrano,R Nandakumar,A Powell,F Stagni,H Schindler,R M D Mamunur,P Naik,R Santacesaria,D L Perego,G Haefeli,C Göbel,J A Hernando Morata,X Yuan,Y Li,P Perret,J H Lopes,J M Otalora Goicochea,L Li Gioi,G Lanfranchi,M Benayoun,M Orlandea,O Aquines Gutierrez,M Szczekowski,R Ekelhof,R Lindner,A Shires,S Wandernoth,I Nasteva,B Pie Valls,M Witek,K Müller,S C Haines,C R Jones,V Bocci,Z Xing,C Blanks,V Shevchenko,I Mous,U Kerzel,E Polycarpo,H Degaudenzi,W Bonivento,F Blanc,C Lazzeroni,R Graciani Diaz,L A Granado Cardoso,M Frosini,G A Cowan,P Jaton,M S Rangel,P E L Clarke,W Witzeling,J Garofoli,D Websdale,L De Paula,A Gomes,J Closier,A D Nguyen,I Videau,B K Pal,M Kaballo,A Leflat,C Thomas,J Benton,C Voß,S Donleavy,S Vecchi,O Schneider,R Santinelli,F Maciuc,I De Bonis,A Martín Sánchez,S Gregson,N Neufeld,M M Reid,J Bressieux,N K Watson,R Gauld,M Veltri,F J P Soler,M Pepe Altarelli,R Silva Coutinho,C Barschel,P Owen,A Jaeger,F Dupertuis,J Lefrançois,M T Tran,F Kruse,D Souza,C Bauer,A Solomin,V Fave,M Palutan,S Wright,Ph Charpentier,S Swientek,J Magnin,D Wiedner,R Vazquez Gomez,P De Simone,O Callot,M Hoballah,V Tisserand,F Teubert,G Wilkinson,J Merkel,S Stoica,A Martens,C Farinelli,D Volyanskyy,G D Patel,N Mangiafave,J M De Miranda,E Hicks,J He,G Krocker,C Adrover,S Redford,A A Alves,O Okhrimenko,A Vollhardt,I Burducea,M Coombes,A Kozlinskiy,D Elsby,D Lambert,C Bozzi,N Rauschmayr,G Mcgregor,A Bay,D R Ward,R J Barlow,M Sapunov,W Baldini,C Coca,M Liles,T Britton,V K Subbiah,D Dossett,V Gibson,E Lopez Asamar,J Harrison,A Bates,P Sail,C Patrignani,V Kudryavtsev,J Wicht,J Rouvinet,B Souza De Paula,M Kucharczyk,D Pinci,A Puig Navarro,A Borgia,F Domingo Bonal,I R Kenyon,N Sagidova,V Niess,S Ricciardi,M Tobin,D Van Eijk,L Garrido,B Viaud,J Wishahi,V Fernandez Albor,E Jans,W Qian,F F Wilson,P Gandini,S Belogurov,M Britsch,G N Patrick,F Ferreira Rodrigues,V Heijne,P Spradlin,M Grabalosa Gándara,A Richards,I V Machikhiliyan,S Oggero,E Thomas,R Le Gac,R Märki,E Ben-Haim,D Voong,K Ciba,S Tourneur,P Schaack,J Beddow,M Perrin-Terrin,L Carson,R Currie,A Vorobyev,P Krokovny,H V Cliff,B Adeva,O Leroy,U Egede,P David,A Ukleja,Y M Kim,M Pló Casasús ,C D’Ambrosio,N López-March ,P Chen,D C Craik ,F Fontanelli,A Bizzeti,F Dettori,Y Xie,D Hutchcroft,A 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Langenbruch,A Pellegrino,Y Amhis,K Rinnert,O De Aguiar Francisco ,D Martínez Santos ,P Alvarez Cartelle,S Easo,A Contu,F Machefert,L Li,F Alessio,S De Capua,O Deschamps,I Shapoval,B Sciascia,S Farry,A Schopper,J J Velthuis,J Dickens,K Kreplin,S T Harnew,C Matteuzzi,S Barsuk,M Smith,H A Gordon ,G Veneziano,P Ilten,N Bondar,V Egorychev,A Bursche,W C Zhang,N A Smith,J Molina Rodriguez,T Szumlak,J P Lees ,P Rodríguez Pérez ,T Kvaratskheliya,K Hennessy,J Panman,G Pessina,R Schwemmer,В Яковенко ,Y Shcheglov,M Cattaneo,S Amato,B Saitta,A Massafferri,Z Ajaltouni,D A Milanés ,O Grünberg,R Lefèvre,G Martellotti,E Aslanides,D Esperante Pereira,M Schlupp,C Frei,J Van Tilburg,V Balagura,M Sannino,M Pappagallo,Д Деркач

doi:10.1007/jhep11(2012)031

Abstract

Abstract The production of χb(1P ) mesons in pp collisions at a centre-of-mass energy of 7 TeV is studied using 32 pb−1 of data collected with the LHCb detector. The χb(1P ) mesons are reconstructed in the decay mode χ b (1P ) → Υ (1S)γ → μ + μ −γ. The fraction of Υ (1S) originating from χb(1P ) decays in the Υ (1S) transverse momentum range 6 < pT Υ (1S) < 15 GeV/c and rapidity range 2.0 < y Υ (1S) < 4.5 is measured to be $ \left( {20.7\pm 5.7\pm 2.1_{-5.4}^{+2.7 }} \right)\% $ , where the first uncertainty is statistical, the second is systematic and the last gives the range of the result due to the unknown Υ (1S) and χb(1P) polarizations.

Highlights

The trigger consists of a hardware stage followed by a software stage which applies a full event reconstruction
The detector includes a high precision tracking system consisting of a silicon-strip vertex detector surrounding the pp interaction region, a large-area silicon-strip detector located upstream of a dipole magnet with a bending power of about 4 Tm, and three stations of siliconstrip detectors and straw drift tubes placed downstream
The combined tracking system has a momentum resolution ∆p/p that varies from 0.4% at 5 GeV/c to 0.6% at 100 GeV/c, and an impact parameter resolution of 20 μm for tracks with high transverse momentum

Summary

LHCb detector

The LHCb detector [15] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks. Electron and hadron candidates are identified by a calorimeter system consisting of scintillating-pad and preshower detectors, an electromagnetic calorimeter and a hadronic calorimeter. The nominal detector performance for photons and muons is described in [15]. The processes of radiative transitions of χcJ → J/ψγ, J = 1, 2 with similar kinematics of the photons are studied in [9, 10]. Another physical analysis which uses π0 → γγ, η → γγ and η′ → ρ0γ is available as [16]. The simulated signal events contain at least one Υ (1S) → μ+μ− decay with both muons in the LHCb acceptance. In this sample of simulated events the fraction of Υ (1S) mesons produced in χb(1P ) decays is 47% and both the χb(1P ) and Υ (1S) mesons are produced unpolarized

Event selection

Systematic uncertainties

Results and conclusions