A1 Journal article (refereed), original research

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

Open Access publication

Publication Details
Authors: Tuuva Tuure, Talvitie Joonas, Khachatryan V., Sirunyan A.M., Tumasyan A., Adam W., Asilar E., Bergauer T., Brandstetter J., Brondolin E., Dragicevic M., Erö J., Flechl M., Friedl M., Frühwirth R., Ghete V.M., Hartl C., Hörmann N., Hrubec J., CMS Collaboration
Publisher: Elsevier: SCOAP3 / Elsevier
Publication year: 2017
Language: English
Related Journal or Series Information: Physics Letters B
Volume number: 772
Start page: 489
End page: 511
Number of pages: 23
ISSN: 0370-2693
eISSN: 1873-2445
JUFO-Level of this publication: 2
Open Access: Open Access publication


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.

Last updated on 2018-19-10 at 07:55