2023/10/26 by LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb +1083 · 1 voice
Physics and Astronomy · #nucl-ex #hep-ex
paper · pdf · doi:10.1103/physrevc.109.024907
arxiv published 2023/10/26 · arxiv updated 2025/02/13
The production of η and η' mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13~\rm TeV, and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16~\rm TeV. The studies are performed in center-of-mass rapidity regions 2.5<y\rm c.m.<3.5 (forward rapidity) and -4.0<y\rm c.m.<-3.0 (backward rapidity) defined relative to the proton beam direction. The η and η' production cross sections are measured differentially as a function of transverse momentum for 1.5<p\rm T<10~\rm GeV and 3<p\rm T<10~\rm GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η and η' mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η mesons are also used to calculate η/π0 cross section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass-dependent nuclear effects in heavy-ion collisions, as well as η and η' meson fragmentation.