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Title: Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV

Abstract

The nuclear modification factors of J/$$\psi$$ and $$\psi$$(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of $$\sqrt{s_{\mathrm{NN}}} =$$ 5.02 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 $$\mu$$b$$^{-1}$$ and 28 pb$$^{-1}$$, respectively. The measurements are performed in the dimuon rapidity range of $|y| <$ 2.4 as a function of centrality, rapidity, and transverse momentum (p$$_\mathrm{T}$$) from p$$_\mathrm{T}=$$ 3 GeV/$c$ in the most forward region and up to 50 GeV/$c$. Both prompt and nonprompt (coming from b hadron decays) mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at $$\sqrt{s_{\mathrm{NN}}}=$$ 2.76 TeV for the two J/$$\psi$$ meson components. No dependence on rapidity is observed for either prompt or nonprompt J/$$\psi$$ mesons. An indication of a lower prompt J/$$\psi$$ meson suppression at high p$$_\mathrm{T}$$ is seen with respect to that observed at intermediate p$$_\mathrm{T}$$. The prompt $$\psi$$(2S) meson yield is found to be more suppressed than that of the prompt J/$$\psi$$ mesons in the entire p$$_\mathrm{T}$$ range.

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:
1415824
Report Number(s):
FERMILAB-PUB-17-616-CMS; CMS-HIN-16-025; CERN-EP-2017-308; arXiv:1712.08959
1644903
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Sirunyan, Albert M, and et al. Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV. United States: N. p., 2017. Web.
Sirunyan, Albert M, & et al. Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV. United States.
Sirunyan, Albert M, and et al. 2017. "Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV". United States. doi:. https://www.osti.gov/servlets/purl/1415824.
@article{osti_1415824,
title = {Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV},
author = {Sirunyan, Albert M and et al.},
abstractNote = {The nuclear modification factors of J/$\psi$ and $\psi$(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}} =$ 5.02 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 $\mu$b$^{-1}$ and 28 pb$^{-1}$, respectively. The measurements are performed in the dimuon rapidity range of $|y| <$ 2.4 as a function of centrality, rapidity, and transverse momentum (p$_\mathrm{T}$) from p$_\mathrm{T}=$ 3 GeV/$c$ in the most forward region and up to 50 GeV/$c$. Both prompt and nonprompt (coming from b hadron decays) mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at $\sqrt{s_{\mathrm{NN}}}=$ 2.76 TeV for the two J/$\psi$ meson components. No dependence on rapidity is observed for either prompt or nonprompt J/$\psi$ mesons. An indication of a lower prompt J/$\psi$ meson suppression at high p$_\mathrm{T}$ is seen with respect to that observed at intermediate p$_\mathrm{T}$. The prompt $\psi$(2S) meson yield is found to be more suppressed than that of the prompt J/$\psi$ mesons in the entire p$_\mathrm{T}$ range.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}
  • The nuclear modification factormore » $${R_{\mathrm{AA}}} $$ and the azimuthal anisotropy coefficient $${v_{2}} $$ of prompt and nonprompt (i.e. those from decays of b hadrons) $$\mathrm{J}/\psi$$ mesons, measured from PbPb and pp collisions at $$\sqrt{s_{\mathrm{NN}}} = $$ 2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta $$p_{\mathrm{T}} > $$ 6.5 GeV/$c$ and rapidity $$| {y} | < $$ 2.4, extending down to $$p_{\mathrm{T}}= $$ 3 GeV/$c$ in the 1.6 $$ < |{y}| < $$ 2.4 range. The $${v_{2}} $$ of prompt $$\mathrm{J}/\psi$$ is found to be nonzero and constant over the full kinematic range studied, while the measured $${v_{2}} $$ of nonprompt $$\mathrm{J}/\psi$$ is consistent with zero. The $${R_{\mathrm{AA}}} $$of prompt $$\mathrm{J}/\psi$$ exhibits a suppression that increases with centrality but does not vary as a function of either $y$ or $$p_{\mathrm{T}}$$ in the fiducial range. The nonprompt $$\mathrm{J}/\psi {R_{\mathrm{AA}}} $$ shows a suppression which becomes stronger as rapidity or $$ p_{\mathrm{T}}$$ increase. Furthermore, the $${v_{2}} $$ and nuclear suppression of open and hidden charm, and of open charm and beauty, are compared.« less
  • This paper reports the measurement of J/ψ meson production in proton–proton (pp) and proton–lead (pPb) collisions at a center-of-mass energy per nucleon pair of 5.02TeV by the CMS experiment at the LHC. The data samples used in the analysis correspond to integrated luminosities of 28pb –1 and 35nb –1 for pp and pPb collisions, respectively. Prompt and nonprompt J/ψ mesons, the latter produced in the decay of B hadrons, are measured in their dimuon decay channels. Differential cross sections are measured in the transverse momentum range of 2 < p T<30GeV/c, and center-of-mass rapidity ranges of |y CM| < 2.4more » (pp) and –2.87 < y CM < 1.93 (pPb). The nuclear modification factor, R pPb, is measured as a function of both p T and y CM. Small modifications to the J/ψ cross sections are observed in pPb relative to pp collisions. The ratio of J/ψ production cross sections in p-going and Pb-going directions, RFB, studied as functions of p T and y CM, shows a significant decrease for increasing transverse energy deposited at large pseudorapidities. Finally, these results, which cover a wide kinematic range, provide new insight on the role of cold nuclear matter effects on prompt and nonprompt J/ψ production.« less
  • The prompt D0 meson azimuthal anisotropy coefficients, v[2] and v[3], are measured at midrapidity (abs(y) < 1.0) in PbPb collisions at a center-of-mass energy sqrt(s[NN]) = 5.02 TeV per nucleon pair with data collected by the CMS experiment. The measurement is performed in the transverse momentum (pT) range of 1 to 40 GeV/c, for central and midcentral collisions. The v[2] coefficient is found to be positive throughout the pT range studied. The first measurement of the prompt D0 meson v[3] coefficient is performed, and values up to 0.07 are observed for pT around 4 GeV/c. Compared to measurements of chargedmore » particles, a similar pT dependence, but smaller magnitude for pT < 6 GeV/c, is found for prompt D0 meson v[2] and v[3] coefficients. The results are consistent with the presence of collective motion of charm quarks at low pT and a path length dependence of charm quark energy loss at high pT, thereby providing new constraints on the theoretical description of the interactions between charm quarks and the quark-gluon plasma.« less
  • The relative modification of the prompt ψ(2S) and J/ψ yields from pp to PbPb collisions, at the center-of-mass energy of 5.02 TeV per nucleon pair, is presented. The analysis is based on pp and PbPb data samples collected by the CMS experiment at the LHC in 2015, corresponding to integrated luminosities of 28.0 pb -1 and 464 μb -1, respectively. The double ratio of measured yields of prompt charmonia reconstructed through their decays into muon pairs, (N ψ(2S)/N J/ψ) PbPb/(N ψ(2S)/N J/ψ) pp, is determined as a function of PbPb collision centrality and charmonium transverse momentum p T, in two kinematicmore » intervals: |y|<1.6 covering 6.5< pT<30 GeV/c and 1.6<|y|<2.4 covering 3< pT<30 GeV/c. The centrality-integrated double ratios are 0.36 ± 0.08(stat) ±0.05 (syst) in the first interval and 0.24 ± 0.22(stat) ± 0.09 (syst) in the second. The double ratio is lower than unity in all the measured bins, suggesting that the ψ(2S) yield is more suppressed than the J/ψ yield in the explored phase space.« less
  • The relative modification of the prompt ψ(2S) and J/ψ yields from pp to PbPb collisions, at the center-of-mass energy of 5.02 TeV per nucleon pair, is presented. The analysis is based on pp and PbPb data samples collected by the CMS experiment at the LHC in 2015, corresponding to integrated luminosities of 28.0 pb -1 and 464 μb -1, respectively. The double ratio of measured yields of prompt charmonia reconstructed through their decays into muon pairs, (N ψ(2S)/N J/ψ) PbPb/(N ψ(2S)/N J/ψ) pp, is determined as a function of PbPb collision centrality and charmonium transverse momentum p T, in two kinematicmore » intervals: |y|<1.6 covering 6.5< pT<30 GeV/c and 1.6<|y|<2.4 covering 3< pT<30 GeV/c. The centrality-integrated double ratios are 0.36 ± 0.08(stat) ±0.05 (syst) in the first interval and 0.24 ± 0.22(stat) ± 0.09 (syst) in the second. The double ratio is lower than unity in all the measured bins, suggesting that the ψ(2S) yield is more suppressed than the J/ψ yield in the explored phase space.« less