Coherent J/ψ photoproduction in ultra-peripheral PbPb collisions at √sNN=2.76 TeV with the CMS experiment

CMS Collaboration

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The cross section for coherent J/ψ photoproduction accompanied by at least one neutron on one side of the interaction point and no neutron activity on the other side, Xn0n, is measured with the CMS experiment in ultra-peripheral PbPb collisions at √sNN = 2.76 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 159μb−1, collected during the 2011 PbPb run. The J/ψ mesons are reconstructed in the dimuon decay channel, while neutrons are detected using zero degree calorimeters. The measured cross section is dσcohXn0n/dy(J/ψ) = 0.36 ±0.04 (stat) ± 0.04 (syst) mb in the rapidity interval 1.8 < |y| <2.3. Using a model for the relative rate of coherent photoproduction processes, this Xn00 measurement gives a total coherent photoproduction cross section of dσcoh/dy(J/ψ) = 1.82 ± 0.22 (stat) ± 0.20 (syst) ± 0.19 (theo) mb. The data strongly disfavor the impulse approximation model prediction, indicating that nuclear effects are needed to describe coherent J/ψ photoproduction in γ+Pb interactions. The data are found to be consistent with the leading twist approximation, which includes nuclear gluon shadowing.
Original languageEnglish
Pages (from-to)489-511
Number of pages23
JournalPhysics Letters B
Volume772
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • CMS
  • Physics
  • Heavy ion collisions
  • Ultra-peripheral collisions
  • UPC
  • J/Psi

Cite this

@article{6e45fc0957a4413283f658a3e66270cd,
title = "Coherent J/ψ photoproduction in ultra-peripheral PbPb collisions at √sNN=2.76 TeV with the CMS experiment",
abstract = "The cross section for coherent J/ψ photoproduction accompanied by at least one neutron on one side of the interaction point and no neutron activity on the other side, Xn0n, is measured with the CMS experiment in ultra-peripheral PbPb collisions at √sNN = 2.76 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 159μb−1, collected during the 2011 PbPb run. The J/ψ mesons are reconstructed in the dimuon decay channel, while neutrons are detected using zero degree calorimeters. The measured cross section is dσcohXn0n/dy(J/ψ) = 0.36 ±0.04 (stat) ± 0.04 (syst) mb in the rapidity interval 1.8 < |y| <2.3. Using a model for the relative rate of coherent photoproduction processes, this Xn00 measurement gives a total coherent photoproduction cross section of dσcoh/dy(J/ψ) = 1.82 ± 0.22 (stat) ± 0.20 (syst) ± 0.19 (theo) mb. The data strongly disfavor the impulse approximation model prediction, indicating that nuclear effects are needed to describe coherent J/ψ photoproduction in γ+Pb interactions. The data are found to be consistent with the leading twist approximation, which includes nuclear gluon shadowing.",
keywords = "CMS, Physics, Heavy ion collisions, Ultra-peripheral collisions, UPC, J/Psi",
author = "Jordan Nash and {CMS Collaboration}",
year = "2017",
doi = "10.1016/j.physletb.2017.07.001",
language = "English",
volume = "772",
pages = "489--511",
journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",
issn = "0370-2693",
publisher = "Elsevier",

}

Coherent J/ψ photoproduction in ultra-peripheral PbPb collisions at √sNN=2.76 TeV with the CMS experiment. / CMS Collaboration.

In: Physics Letters B, Vol. 772, 2017, p. 489-511.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Coherent J/ψ photoproduction in ultra-peripheral PbPb collisions at √sNN=2.76 TeV with the CMS experiment

AU - Nash, Jordan

AU - CMS Collaboration

PY - 2017

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N2 - The cross section for coherent J/ψ photoproduction accompanied by at least one neutron on one side of the interaction point and no neutron activity on the other side, Xn0n, is measured with the CMS experiment in ultra-peripheral PbPb collisions at √sNN = 2.76 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 159μb−1, collected during the 2011 PbPb run. The J/ψ mesons are reconstructed in the dimuon decay channel, while neutrons are detected using zero degree calorimeters. The measured cross section is dσcohXn0n/dy(J/ψ) = 0.36 ±0.04 (stat) ± 0.04 (syst) mb in the rapidity interval 1.8 < |y| <2.3. Using a model for the relative rate of coherent photoproduction processes, this Xn00 measurement gives a total coherent photoproduction cross section of dσcoh/dy(J/ψ) = 1.82 ± 0.22 (stat) ± 0.20 (syst) ± 0.19 (theo) mb. The data strongly disfavor the impulse approximation model prediction, indicating that nuclear effects are needed to describe coherent J/ψ photoproduction in γ+Pb interactions. The data are found to be consistent with the leading twist approximation, which includes nuclear gluon shadowing.

AB - The cross section for coherent J/ψ photoproduction accompanied by at least one neutron on one side of the interaction point and no neutron activity on the other side, Xn0n, is measured with the CMS experiment in ultra-peripheral PbPb collisions at √sNN = 2.76 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 159μb−1, collected during the 2011 PbPb run. The J/ψ mesons are reconstructed in the dimuon decay channel, while neutrons are detected using zero degree calorimeters. The measured cross section is dσcohXn0n/dy(J/ψ) = 0.36 ±0.04 (stat) ± 0.04 (syst) mb in the rapidity interval 1.8 < |y| <2.3. Using a model for the relative rate of coherent photoproduction processes, this Xn00 measurement gives a total coherent photoproduction cross section of dσcoh/dy(J/ψ) = 1.82 ± 0.22 (stat) ± 0.20 (syst) ± 0.19 (theo) mb. The data strongly disfavor the impulse approximation model prediction, indicating that nuclear effects are needed to describe coherent J/ψ photoproduction in γ+Pb interactions. The data are found to be consistent with the leading twist approximation, which includes nuclear gluon shadowing.

KW - CMS

KW - Physics

KW - Heavy ion collisions

KW - Ultra-peripheral collisions

KW - UPC

KW - J/Psi

U2 - 10.1016/j.physletb.2017.07.001

DO - 10.1016/j.physletb.2017.07.001

M3 - Article

VL - 772

SP - 489

EP - 511

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

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