Journal Article

Measurement of the forward Z boson production cross-section in pp collisions at s=7 TeV

Jurik, N., Vorobyev, V., Chefdeville, M., Di Canto, A., Hicheur, A., Pepe Altarelli, M., Popov, D., Stahl, M., Alexander, M., De Cian, M., Deschamps, O., Wang, J., Jones, C. R., Durante, P., Gao, Y., Dreimanis, K., Maurin, B., Yang, Z., Cardinale, R., Gianì, S., Lees, J.-P., Vieites Diaz, M., Barlow, R. J., Nikodem, T., Ilten, P., Schmelling, M., Lanfranchi, G., Battista, V., Vázquez Sierra, C., Matev, R., Jans, E., Bedeschi, F., Romero Vidal, A., Gavardi, L., Kucewicz, W., Okhrimenko, O., Swientek, K., Haines, S. C., Henrard, P., Pugatch, V., Torr, N., Bonivento, W., Ketel, T., Ekelhof, R., Ferro-Luzzi, M., Oldeman, R., Hussain, N., Lefèvre, R., Golubkov, D., Shevchenko, V., Morello, M. J., Cheung, S.-F., Dalseno, J., Jawahery, A., Lai, A., Schneider, O., Rama, M., Soler, F. J. P., Bozzi, C., Carniti, P., Joram, C., Tran, M. T., Sciubba, A., Fontana, M., Ruiz Valls, P., Gastaldi, U., Campora Perez, D., Sterpka, F., Straticiuc, M., Cenci, R., Smith, E., Egorychev, V., Marchand, J. F., Gibson, V., Tisserand, V., Storaci, B., Soomro, F., Tuning, N., Kvaratskheliya, T., Chen, S., Walsh, J., Luo, H., Morris, A. B., Carboni, G., Geraci, A., Bel, L. J., Morand

2015

Overview

A bstract A measurement of the production cross-section for Z bosons that decay to muons is presented. The data were recorded by the LHCb detector during pp collisions at a centre-of-mass energy of 7 TeV, and correspond to an integrated luminosity of 1.0 fb −1 . The cross-section is measured for muons in the pseudorapidity range 2 . 0 < η < 4 . 5 with transverse momenta p T > 20 GeV /c . The dimuon mass is restricted to 60 < M μ + μ − < 120 GeV /c 2 . The measured cross-section is σ Z → μ + μ − = 76.0 ± 0.3 ± 0.5 ± 1.0 ± 1.3 p b where the uncertainties are due to the sample size, systematic effects, the beam energy and the luminosity. This result is in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. The cross-section is also measured differentially as a function of kinematic variables of the Z boson. Ratios of the production cross-sections of electroweak bosons are presented using updated LHCb measurements of W boson production. A precise test of the Standard Model is provided by the measurement of the ratio σ W + → μ + ν μ + σ W − → μ − ν ¯ μ σ Z → μ + μ − = 20.63 ± 0.09 ± 0.12 ± 0.05 , where the uncertainty due to luminosity cancels.

• Publisher: Springer Berlin Heidelberg
• Subject: Classical and Quantum Gravitation / Elementary Particles / Physics / Physics and Astronomy / Quantum Field Theories / Quantum Field Theory / Quantum Physics / Regular Article - Experimental Physics / Relativity Theory / String Theory