Observation of Nuclear Suppression in Coherent ϒ(1S) Photoproduction off Heavy Nuclei at the LHC


Belyaev A., Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J., Benato L., ...Daha Fazla

Physical review letters, cilt.137, sa.14, ss.142301, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 137 Sayı: 14
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1103/ll3f-l5xv
  • Dergi Adı: Physical review letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MathSciNet, MEDLINE, zbMATH, DIALNET
  • Sayfa Sayıları: ss.142301
  • Çukurova Üniversitesi Adresli: Evet

Özet

The first measurement of coherent ϒ(1S) meson photoproduction off heavy nuclei is performed using ultraperipheral lead-lead collisions collected by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The nuclear gluonic structure is probed at a nucleon momentum fraction of order x∼10^{-3}, determined by the kinematics of the process. Owing to the large ϒ(1S) mass, the measurement reaches the highest scale accessible so far through coherent vector-meson photoproduction, μ^{2}=22.4 GeV^{2}, where nonlinear quantum chromodynamics effects are expected to be minimal. In the ϒ(1S) rapidity range |y|<1, the ratio of the measured photoproduction cross section to a baseline model prediction that neglects nuclear effects is S_{ϒ(1S)}=0.25±0.06(stat)±0.02(syst), thereby demonstrating nuclear suppression in this process. Expressed in terms of a nuclear gluon suppression factor, the result yields R_{g}^{Pb}(x≈10^{-3},μ^{2}=22.4 GeV^{2})=0.55±0.12(stat)±0.02(syst). The measured S_{ϒ(1S)} is only slightly larger than the values previously reported for coherent ϕ photoproduction, despite the probed μ^{2} differing by approximately 2 orders of magnitude.