Study of χc production in pPb collisions at √(sNN) = 8.16 TeV
Abstract
Production of prompt P-wave charmonium states χc1(1P) and χc2(1P) is studied in proton-lead (pPb) collisions at a center-of-mass energy per nucleon pair of √(smash[b]sNN) = 8.16 TeV. The analysis is based on data corresponding to an integrated luminosity of 175 nb−1 collected by the CMS experiment at the CERN LHC. The χc states are measured via their decay χc → J/ψ γ. The J/ψ meson is reconstructed via its decay to a muon pair, while the photon is reconstructed through its conversion to an electron-positron pair. The ratio of production cross sections times branching fractions for the two charmonium states, [σ(χc2) ℬ(χc2 → J/ψ γ)] / [σ(χc1) ℬ(χc1 → J/ψ γ)], is reported in the rapidity range | y(J/ψ)| lt 2.4 for the transverse momentum range 6.5 lt pT(J/ψ) lt 30 GeV. The χc2-to-χc1 ratio is found to be independent of event charged-particle multiplicity, as well as of the rapidity and pT of the J/ψ. The consistency of this ratio with proton-proton measurements at √s = 7 TeV indicates an absence of strong relative modification for χc states in pPb collisions, in contrast to the behavior observed in the ψ(2S)-to-J/ψ ratio.
Related
- Theoretical Review on Bulk Properties and Light/Strange Hadron Production in Heavy-Ion Collisions
- Light anti-nuclei in pp collisions at the LHC: production by coalescence and interaction of anti-nucleons
- Particle production in p-O collisions at LHC energy
- Light (anti)nuclei production via coalescence in electron-proton collisions: from HERA to EIC
- Experimental Review on Bulk Properties and Light/Strange Hadron Production in Heavy-Ion Collisions
BibTeX
@misc{collaboration2026study,
title = {{Study of $χ_\mathrmc$ production in pPb collisions at $\sqrts_\mathrmNN$ = 8.16 TeV}},
author = {CMS Collaboration},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.17847},
eprint = {2607.17847},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.17847},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Study of χ_c production in pPb collisions at √(s_NN) = 8.16 TeV
AU - CMS Collaboration
PY - 2026
DA - 2026/10/03
PB - arXiv
DO - 10.48550/arxiv.2607.17847
UR - https://arxiv.org/abs/2607.17847
AB - Production of prompt P-wave charmonium states χ_c1(1P) and χ_c2(1P) is studied in proton-lead (pPb) collisions at a center-of-mass energy per nucleon pair of √(smash[b]s__NN) = 8.16 TeV. The analysis is based on data corresponding to an integrated luminosity of 175 nb^−1 collected by the CMS experiment at the CERN LHC. The χ_c states are measured via their decay χ_c → J/ψ γ. The J/ψ meson is reconstructed via its decay to a muon pair, while the photon is reconstructed through its conversion to an electron-positron pair. The ratio of production cross sections times branching fractions for the two charmonium states, [σ(χ_c2) ℬ(χ_c2 → J/ψ γ)] / [σ(χ_c1) ℬ(χ_c1 → J/ψ γ)], is reported in the rapidity range | y(J/ψ)| lt 2.4 for the transverse momentum range 6.5 lt p_T(J/ψ) lt 30 GeV. The χ_c2-to-χ_c1 ratio is found to be independent of event charged-particle multiplicity, as well as of the rapidity and p_T of the J/ψ. The consistency of this ratio with proton-proton measurements at √s = 7 TeV indicates an absence of strong relative modification for χ_c states in pPb collisions, in contrast to the behavior observed in the ψ(2S)-to-J/ψ ratio.
ER -