Journal Articles

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    Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at √s = 0.9 and 2.36TeV
    (SPRINGER, 1/01/2010) Khachatryan V; Sirunyan AM; Tumasyan A; Adam W; Bergauer T; Dragicevic M; Erö J; Friedl M; Frühwirth R; Ghete VM; Hammer J; Hänsel S; Hoch M; Hörmann N; Hrubec J; Jeitler M; Kasieczka G; Krammer M; Liko D; Mikulec I; Pernicka M; Rohringer H; Schöfbeck R; Strauss J; Taurok A; Teischinger F; Waltenberger W; Walzel G; Widl E; Wulz CE; Mossolov V; Shumeiko N; Suarez Gonzalez J; Benucci L; De Wolf EA; Hashemi M; Janssen X; Maes T; Mucibello L; Ochesanu S; Rougny R; Selvaggi M; Van Haevermaet H; Van Mechelen P; Van Remortel N; Adler V; Beauceron S; D’Hondt J; Devroede O; Kalogeropoulos A; Maes J; Mozer MU; Tavernier S; Van Doninck W; Van Mulders P; Villella I; Chabert EC; Charaf O; Clerbaux B; De Lentdecker G; Dero V; Gay APR; Hammad GH; Marage PE; Vander Velde C; Vanlaer P; Wickens J; Grunewald M; Klein B; Marinov A; Ryckbosch D; Thyssen F; Tytgat M; Vanelderen L; Verwilligen P; Walsh S; Basegmez S; Bruno G; Caudron J; Cortina Gil E; De Favereau De Jeneret J; Delaere C; Demin P; Favart D; Giammanco A; Grégoire G; Hollar J; Lemaitre V; Maltoni F; Militaru O; Ovyn S; Piotrzkowski K; Quertenmont L; Schul N; Beliy N; Caebergs T; Daubie E; Herquet P; Alves GA; Pol ME
    Measurements of inclusive charged-hadron transverse-momentum and pseudorapidity distributions are presented for proton-proton collisions at √s = 0.9 and 2.36 TeV. The data were collected with the CMS detector during the LHC commissioning in December 2009. For non-single-diffractive interactions, the average charged-hadron transverse momentum is measured to be 0:46 ± 0:01 (stat.) ± 0.01 (syst.) GeV/c at 0.9 TeV and 0:50 ± 0:01 (stat.) ± 0.01 (syst.) GeV/c at 2.36 TeV, for pseudorapidities between -2:4 and +2:4. At these energies, the measured pseudorapidity densities in the central region, dNch/dη| |η|>0.5, are 3:48±0:02 (stat.) ± 0.13 (syst.) and 4:47±0:04 (stat.) ± 0.16 (syst.), respectively. The results at 0.9 TeV are in agreement with previous measurements and con- firm the expectation of near equal hadron production in pp̄ and pp collisions. The results at 2.36 TeV represent the highest-energy measurements at a particle collider to date.
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    Measurement of the charge ratio of atmospheric muons with the CMS detector
    (ELSEVIER SCIENCE BV, 1/01/2010) Khachatryan V; Sirunyan AM; Tumasyan A; Adam W; Bergauer T; Dragicevic M; Erö J; Fabjan C; Friedl M; Frühwirth R; Ghete VM; Hammer J; Hänsel S; Hoch M; Hörmann N; Hrubec J; Jeitler M; Kasieczka G; Kiesenhofer W; Krammer M; Liko D; Mikulec I; Pernicka M; Rohringer H; Schöfbeck R; Strauss J; Taurok A; Teischinger F; Waltenberger W; Walzel G; Widl E; Wulz CE; Mossolov V; Shumeiko N; Suarez Gonzalez J; Benucci L; Ceard L; De Wolf EA; Hashemi M; Janssen X; Maes T; Mucibello L; Ochesanu S; Roland B; Rougny R; Selvaggi M; Van Haevermaet H; Van Mechelen P; Van Remortel N; Adler V; Beauceron S; Blyweert S; D'Hondt J; Devroede O; Kalogeropoulos A; Maes J; Maes M; Tavernier S; Van Doninck W; Van Mulders P; Villella I; Chabert EC; Charaf O; Clerbaux B; De Lentdecker G; Dero V; Gay APR; Hammad GH; Marage PE; Vander Velde C; Vanlaer P; Wickens J; Costantini S; Grunewald M; Klein B; Marinov A; Ryckbosch D; Thyssen F; Tytgat M; Vanelderen L; Verwilligen P; Walsh S; Zaganidis N; Basegmez S; Bruno G; Caudron J; De Favereau De Jeneret J; Delaere C; Demin P; Favart D; Giammanco A; Grégoire G; Hollar J; Lemaitre V; Militaru O; Ovyn S; Pagano D; Pin A; Piotrzkowski K; Quertenmont L
    We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/. c to 1 TeV/. c. The surface flux ratio is measured to be 1.2766±0.0032(stat.)±0.0032(syst.), independent of the muon momentum, below 100 GeV/. c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments. © 2010.