Ratios of the Psi' over the J/psi production cross sections in the dilepton channel for C, Ti and W targets have been measured in 920 GeV proton-nucleus interactions with the HERA-B detector at the HERA storage ring. The Psi' and J/psi states were reconstructed in both the mu+mu- and the e+e- decay modes. The measurements covered the kinematic range -0.35 < x_F &lt; 0.1 with transverse momentum p_T &lt; 4.5 GeV/c. The Psi' to J/psi production ratio is almost constant in the covered x_F range and shows a slow increase with p_T. The angular dependence of the ratio has been used to measure the difference of the Psi' and J/psi polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is R_psi'(mu)/R_psi'(e)=1.00+-0.08+-0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B'(mu)*B(e))/(B(mu)*B'(e)), of Psi' and J/psi in the two channels.

A Measurement of the Psi' to J/psi Production Ratio in 920 GeV Proton-Nucleus Interactions

BERTIN, ANTONIO;DE CASTRO, STEFANO;FABBRI, LAURA;FACCIOLI, PIETRO;MASSA, IGNAZIO GIACOMO;PICCININI, MAURIZIO;SBRIZZI, ANTONIO;SEMPRINI CESARI, NICOLA;VILLA, MAURO;VITALE, ANTONIO;ZOCCOLI, ANTONIO
2007

Abstract

Ratios of the Psi' over the J/psi production cross sections in the dilepton channel for C, Ti and W targets have been measured in 920 GeV proton-nucleus interactions with the HERA-B detector at the HERA storage ring. The Psi' and J/psi states were reconstructed in both the mu+mu- and the e+e- decay modes. The measurements covered the kinematic range -0.35 < x_F < 0.1 with transverse momentum p_T < 4.5 GeV/c. The Psi' to J/psi production ratio is almost constant in the covered x_F range and shows a slow increase with p_T. The angular dependence of the ratio has been used to measure the difference of the Psi' and J/psi polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is R_psi'(mu)/R_psi'(e)=1.00+-0.08+-0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B'(mu)*B(e))/(B(mu)*B'(e)), of Psi' and J/psi in the two channels.
I. ABT; M. ADAMS; M. AGARI; H. ALBRECHT; A. ALEKSANDROV; V. AMARAL; A. AMORIM; S.J. APLIN; V. AUSHEV; Y. BAGATURIA; V. BALAGURA; M. BARGIOTTI; O. BARSUKOVA; J. BASTOS; J. BATISTA; C. BAUER; TH.S. BAUER; A. BELKOV; AR. BELKOV; I. BELOTELOV; A. BERTIN; B. BOBCHENKO; M. BOCKER; A. BOGATYREV; G. BOHM; M. BRAUER; M. BRUINSMA; M. BRUSCHI; P. BUCHHOLZ; T. BURAN; J. CARVALHO; P. CONDE; C. CRUSE; M. DAM; K.M. DANIELSEN; M. DANILOV; S. DE CASTRO; H. DEPPE; X. DONG; H.B. DREIS; V. EGORYTCHEV; K. EHRET; F. EISELE; D. EMELIYANOV; S. ERHAN; S. ESSENOV; L. FABBRI; P. FACCIOLI; M. FEUERSTACK-RAIBLE; J. FLAMMER; B. FOMINYKH; M. FUNCKE; LL. GARRIDO; A. GELLRICH; B. GIACOBBE; J. GLA; D. GOLOUBKOV; Y. GOLUBKOV; A. GOLUTVIN; I. GOLUTVIN; I. GORBOUNOV; A. GORISEK; O. GOUCHTCHINE; D.C. GOULART; S. GRADL; W. GRADL; F. GRIMALDI; YU. GUILITSKY; J.D. HANSEN; J.M. HERNANDEZ; W. HOFMANN; M. HOHLMANN; T. HOTT; W. HULSBERGEN; U. HUSEMANN; O. IGONKINA; M. ISPIRYAN; T. JAGLA; C. JIANG; H. KAPITZA; S. KARABEKYAN; N. KARPENKO; S. KELLER; J. KESSLER; F. KHASANOV; YU. KIRYUSHIN; I. KISEL; E. KLINKBY; K.T. KNOPFLE; H. KOLANOSKI; S. KORPAR; C. KRAUSS; P. KREUZER; P. KRIZAN; D. KRUCKER; S. KUPPER; T. KVARATSKHELIIA; A. LANYOV; K. LAU; B. LEWENDEL; T. LOHSE; B. LOMONOSOV; R. MANNER; R. MANKEL; S. MASCIOCCHI; I. MASSA; I. MATCHIKHILIAN; G. MEDIN; M. MEDINNIS; M. MEVIUS; A. MICHETTI; YU. MIKHAILOV; R. MIZUK; R. MURESAN; M.ZUR NEDDEN; M. NEGODAEV; M. NORENBERG; S. NOWAK; M.T. NUNEZ PARDO DE VERA; M. OUCHRIF; F. OULD-SAADA; C. PADILLA; D. PERALTA; R. PERNACK; R. PESTOTNIK; B.A. PETERSEN; M. PICCININI; M.A. PLEIER; M. POLI; V. POPOV; D. POSE; S. PRYSTUPA; V.M. PUGATCH; Y. PYLYPCHENKO; J. PYRLIK; K. REEVES; D. REING; H. RICK; I. RIU; P. ROBMANN; I. ROSTOVTSEVA; V. RYBNIKOV; F. SANCHEZ; A. SBRIZZI; M. SCHMELLING; B. SCHMIDT; A. SCHREINER; H. SCHRODER; U. SCHWANKE; ALAN J. SCHWARTZ; ANDREAS S. SCHWARZ; B. SCHWENNINGER; B. SCHWINGENHEUER; F. SCIACCA; N. SEMPRINI-CESARI; S. SHUVALOV; L. SILVA; L. SOZUER; S. SOLUNIN; A. SOMOV; S. SOMOV; J. SPENGLER; R. SPIGHI; A. SPIRIDONOV; A. STANOVNIK; M. STARIC; C. STEGMANN; H.S. SUBRAMANIA; M. SYMALLA; I. TIKHOMIROV; M. TITOV; I. TSAKOV; U. UWER; C. VAN ELDIK; YU. VASSILIEV; M. VILLA; A. VITALE; I. VUKOTIC; H. WAHLBERG; A.H. WALENTA; M. WALTER; J.J. WANG; D. WEGENER; U. WERTHENBACH; H. WOLTERS; R. WURTH; A. WURZ; YU. ZAITSEV; M. ZAVERTYAEV; T. ZEUNER; A. ZHELEZOV; Z. ZHENG; R. ZIMMERMANN; T. ZIVKO; A. ZOCCOLI
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/36720
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