KAI-FENG CHENPAO-TI CHANGRONG-SHYANG LUWEI-SHU HOU2021-07-282021-07-28202024700010https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096105475&doi=10.1103%2fPhysRevD.102.032007&partnerID=40&md5=ebecb3078f5a8a83d2d47359483d1fc4https://scholars.lib.ntu.edu.tw/handle/123456789/573645Ratios of cross sections, σ(Z+c jets)/σ(Z+jets), σ(Z+b jets)/σ(Z+jets), and σ(Z+c jets)/σ(Z+b jets) in the associated production of a Z boson with at least one charm or bottom quark jet are measured in proton-proton collisions at s=13 TeV. The data sample, collected by the CMS experiment at the CERN LHC, corresponds to an integrated luminosity of 35.9 fb-1, with a fiducial volume of pT>30 GeV and |η|<2.4 for the jets, where pT and η represent transverse momentum and pseudorapidity, respectively. The Z boson candidates come from leptonic decays into electrons or muons with pT>25 GeV and |η|<2.4, and the dilepton mass satisfies 71<mZ<111 GeV. The measured values are σ(Z+c jets)/σ(Z+jets)=0.102±0.002±0.009, σ(Z+b jets)/σ(Z+jets)=0.0633±0.0004±0.0015, and σ(Z+c jets)/σ(Z+b jets)=1.62±0.03±0.15. Results on the inclusive and differential cross section ratios as functions of jet and Z boson transverse momentum are compared with predictions from leading and next-to-leading order perturbative quantum chromodynamics calculations. These are the first measurements of the cross section ratios at 13 TeV. ? 2020 American Physical Society. All rights reserved.journal article10.1103/PhysRevD.102.0320072-s2.0-85096105475