Measurement of the production cross sections for a Z boson and one or more b jets in pp collisions at sqrt(s) = 7 TeV

S. Chatrchyan , S. Baffioni (1) , F. Beaudette (1) , L. Benhabib (1) , M. Bluj (1) , P. Busson (1) , C. Charlot (1) , N. Daci (1) , T. Dahms (1) , M. Dalchenko (1) , L. Dobrzynski (1) , A. Florent (1) , R. Granier de Cassagnac (1) , M. Haguenauer (1) , P. Mine (1) , C. Mironov (1) , I.N. Naranjo (1) , M. Nguyen (1) , C. Ochando (1) , P. Paganini (1) , D. Sabes (1) , R. Salerno (1) , Y. Sirois (1) , C. Veelken (1) , A. Zabi (1) , J.-L. Agram (2) , J. Andrea (2) , D. Bloch (2) , J.-M. Brom (2) , E.C. Chabert (2) , C. Collard (2) , E. Conte (2) , F. Drouhin (2) , J.-C. Fontaine (2) , D. Gele (2) , U. Goerlach (2) , C. Goetzmann (2) , P. Juillot (2) , A.-C. Le Bihan (2) , P. van Hove (2) , S. Gadrat (3) , S. Beauceron (4) , N. Beaupere (4) , G. Boudoul (4) , S. Brochet (4) , J. Chasserat (4) , R. Chierici (4) , D. Contardo (4) , P. Depasse (4) , H. El Mamouni (4) , J. Fay (4) , S. Gascon (4) , M. Gouzevitch (4) , B. Ille (4) , T. Kurca (4) , M. Lethuillier (4) , L. Mirabito (4) , S. Perries (4) , L. Sgandurra (4) , V. Sordini (4) , M. Vander Donckt (4) , P. Verdier (4) , S. Viret (4)

1 LLR - Laboratoire Leprince-Ringuet
2 IPHC - Institut Pluridisciplinaire Hubert Curien
3 CC-IN2P3 - Centre de Calcul de l'IN2P3
4 IPNL - Institut de Physique Nucléaire de Lyon

The production of a Z boson, decaying into two leptons and produced in association with one or more b jets, is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV. The data were recorded in 2011 with the CMS detector and correspond to an integrated luminosity of 5 inverse femtobarns. The Z(ll)+b-jets cross sections (where ll = mu mu or ee) are measured for a Z boson produced with exactly one or at least two b jets. In addition, a cross section ratio is extracted for a Z boson produced with at least one b jet relative to a Z boson produced with at least one jet. The measured cross sections are compared to various theoretical predictions, and the data favour the predictions in the five-flavour scheme, where b quarks are assumed massless. The kinematic properties of the reconstructed particles are compared with the predictions from the MADGRAPH event generator using the PYTHIA parton shower simulation.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

S. Chatrchyan, S. Baffioni, F. Beaudette, L. Benhabib, M. Bluj, et al.. Measurement of the production cross sections for a Z boson and one or more b jets in pp collisions at sqrt(s) = 7 TeV. Journal of High Energy Physics, 2014, 6, pp.120. ⟨10.1007/JHEP06(2014)120⟩. ⟨in2p3-00945588⟩