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Title: Measurement of associated Z + charm production in proton-proton collisions at $$\sqrt{s} = $$ 8 TeV

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 $$p_{\rm T}^{\ell} > $$ 20 GeV, $${|\eta^{\ell}|} < $$ 2.1, 71 $$ < m_{\ell\ell} < $$ 111 GeV, and heavy flavour jets with $$p_{\rm T}^{{\rm jet}} > $$ 25 GeV and $${|\eta^{{\rm jet}}|} < $$ 2.5. The Z + c production cross section is measured to be $$\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X}) {\cal B}(\mathrm{Z} \rightarrow \ell^+\ell^-) = $$ 8.8 $$\pm$$ 0.5 (stat) $$\pm$$ 0.6 (syst) pb. The ratio of the Z + c and Z + b production cross sections is measured to be $$\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X})/\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{b} + \mathrm{X}) = $$ 2.0 $$\pm$$ 0.2 (stat) $$\pm$$ 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 the Z boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.

Authors:
;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1409374
Report Number(s):
FERMILAB-PUB-17-532-CMS; CMS-SMP-15-009; CERN-EP-2017-257; arXiv:1711.02143
1634835
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Sirunyan, Albert M, and et al. Measurement of associated Z + charm production in proton-proton collisions at $\sqrt{s} = $ 8 TeV. United States: N. p., 2017. Web.
Sirunyan, Albert M, & et al. Measurement of associated Z + charm production in proton-proton collisions at $\sqrt{s} = $ 8 TeV. United States.
Sirunyan, Albert M, and et al. 2017. "Measurement of associated Z + charm production in proton-proton collisions at $\sqrt{s} = $ 8 TeV". United States. doi:. https://www.osti.gov/servlets/purl/1409374.
@article{osti_1409374,
title = {Measurement of associated Z + charm production in proton-proton collisions at $\sqrt{s} = $ 8 TeV},
author = {Sirunyan, Albert M and et al.},
abstractNote = {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 $p_{\rm T}^{\ell} > $ 20 GeV, ${|\eta^{\ell}|} < $ 2.1, 71 $ < m_{\ell\ell} < $ 111 GeV, and heavy flavour jets with $p_{\rm T}^{{\rm jet}} > $ 25 GeV and ${|\eta^{{\rm jet}}|} < $ 2.5. The Z + c production cross section is measured to be $\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X}) {\cal B}(\mathrm{Z} \rightarrow \ell^+\ell^-) = $ 8.8 $\pm$ 0.5 (stat) $\pm$ 0.6 (syst) pb. The ratio of the Z + c and Z + b production cross sections is measured to be $\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X})/\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{b} + \mathrm{X}) = $ 2.0 $\pm$ 0.2 (stat) $\pm$ 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 the Z boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}
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