CMS-PAS-HIN-18-003

CMS-PAS-HIN-18-003
Differential measurements of the Drell-Yan process in the muon channel in pPb collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 8.16 TeV
CMS Collaboration
May 2020

Abstract: Measurements of differential cross sections for the Drell-Yan process, including Z boson production, in proton-lead (pPb) collisions at a nucleon-nucleon centre-of-mass energy of 8.16 TeV are presented, in the muon channel. A data sample recorded with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 173.4 $\pm$ 6.1 nb$^{-1}$. The differential cross section $\textrm{d}\sigma / \textrm{d}m_{\mu\mu}$ in the dimuon mass range 15 $ < m_{\mu\mu} < $ 600 GeV is measured with the CMS detector, for the first time in heavy ion collisions, and reported before and after correction to the full phase space, given by the dimuon rapidity $y_{\rm{CM}}$ in the centre-of-mass frame from $ -2.87 $ to $ 1.93 $. The differential cross section $\textrm{d}\sigma/\textrm{d}y_{\rm{CM}}$ is also measured over the mass ranges 15-60 and 60-120 GeV, and same dimuon rapidity range. Ratios of dimuon yields for the proton-going over the Pb-going beam directions are built in the range $\|y_{\rm{CM}}\| < $ 1.93. In both mass ranges, the differential cross sections $\textrm{d}\sigma / \textrm{d}p_{\rm{T}}$ and $\textrm{d}\sigma / \textrm{d}\phi^{}$ are measured, where the kinematic observable $\phi^{}$ correlates with the dimuon transverse momentum but only depends on angular quantities. Results are compared to predictions at next-to-leading order, including nuclear modifications of parton distribution functions, which they could help better constrain.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 05 (2021) 182. The superseded preliminary plots can be found here.

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