TY - JOUR
T1 - Coherent J/ψ photoproduction in ultra-peripheral PbPb collisions at sNN=2.76TeV with the CMS experiment
AU - The CMS collaboration
AU - Khachatryan, V.
AU - Sirunyan, A. M.
AU - Tumasyan, A.
AU - Adam, W.
AU - Asilar, E.
AU - Bergauer, T.
AU - Brandstetter, J.
AU - Brondolin, E.
AU - Dragicevic, M.
AU - Erö, J.
AU - Flechl, M.
AU - Friedl, M.
AU - Frühwirth, R.
AU - Ghete, V. M.
AU - Hartl, C.
AU - Hörmann, N.
AU - Hrubec, J.
AU - Jeitler, M.
AU - König, A.
AU - Krammer, M.
AU - Krätschmer, I.
AU - Liko, D.
AU - Matsushita, T.
AU - Mikulec, I.
AU - Rabady, D.
AU - Rad, N.
AU - Rahbaran, B.
AU - Rohringer, H.
AU - Schieck, J.
AU - Schöfbeck, R.
AU - Strauss, J.
AU - Treberer-Treberspurg, W.
AU - Waltenberger, W.
AU - Wulz, C. E.
AU - Mossolov, V.
AU - Shumeiko, N.
AU - Suarez Gonzalez, J.
AU - Alderweireldt, S.
AU - Cornelis, T.
AU - De Wolf, E. A.
AU - Janssen, X.
AU - Knutsson, A.
AU - Lauwers, J.
AU - Luyckx, S.
AU - Van De Klundert, M.
AU - Van Haevermaet, H.
AU - Van Mechelen, P.
AU - Marlow, Daniel Robert
AU - Olsen, James D.
AU - Tully, Christopher George
N1 - Publisher Copyright:
© 2017 The Author(s)
PY - 2017/9/10
Y1 - 2017/9/10
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=2.76TeV. 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 dσXn0n coh/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 Xn0n 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=2.76TeV. 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 dσXn0n coh/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 Xn0n 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 - Heavy ion collisions
KW - J/Psi
KW - Physics
KW - UPC
KW - Ultra-peripheral collisions
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U2 - 10.1016/j.physletb.2017.07.001
DO - 10.1016/j.physletb.2017.07.001
M3 - Article
AN - SCOPUS:85030700462
SN - 0370-2693
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
ER -