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Committee for collaboration of Czech Republic

with Joint Institute for Nuclear Research in Dubna Login
Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV

Author
Sirunyan A.M. Yerevan Physics Institute, Armenia
Finger Miroslav, prof. Ing. DrSc. Faculty of Mathematics and Physics, Charles University in Prague
Finger Michael, M.Sc. CSc. Faculty of Mathematics and Physics, Charles University in Prague, JINR Dubna
et al.  CMS collaboration

Year
2018

Scientific journal
European Physical Journal C, 78 (4), 287

Web


Abstract
A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with pT(l) > 20 GeV, vertical bar eta(l)vertical bar < 2.1, 71 < m(ll) < 111 GeV, and heavy flavour jets with p(T)(jet) > 25 GeV and vertical bar eta(jet)vertical bar < 2.5. The Z + c production cross section is measured to be sigma(pp -> Z + c + X) B(Z -> l(+)l(-)) = 8.8 +/- 0.5 (stat)+/- 0.6 (syst) pb. The ratio of the Z+c and Z+b production cross sections is measured to be sigma(pp -> Z+c+X)/sigma (pp -> Z+b+X) = 2.0 +/- 0.2 (stat)+/- 0.2 (syst). The Z+c production cross section and the cross section ratio are also measured as a function of the transverse momentum of theZ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.

Cite article as:
A. Sirunyan, M. Finger, M. Finger, . et al., "Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV", European Physical Journal C, 78 (4), 287 (2018)