2026/02/24 by A. Belyaev, CMS Collaboration, Arzunik Gevorgyan +98 · 2 voices · 2 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Dust and Plasma Wave Phenomena #Magnetic confinement fusion research
paper · pdf · doi:10.1016/j.physletb.2026.140679
High-energy partons lose energy while propagating through the hot, strongly interacting medium produced in ultrarelativistic nucleus-nucleus collisions, leading to a suppression of particle production at high transverse momentum ( p T ). The dependence of this energy loss on the size of the colliding nuclear system has yet to be firmly established experimentally. This Letter presents a systematic study of charged-particle suppression across four different nucleus-nucleus collision systems using nuclear modification factors ( R AA ) measured by the CMS Collaboration at the CERN LHC. Previous CMS measurements of R AA in oxygen-oxygen, xenon-xenon, and lead-lead collisions are recast with identical p T intervals and are complemented by the first measurement of the charged-particle R AA in neon-neon collisions at [ b ] s NN = 5.36 TeV . The neon-neon data correspond to an integrated luminosity of 0.76 nb − 1 . The R AA in all collision systems examined show similar qualitative trends as a function of p T , but have a magnitude which is ordered with the nucleon number A . The R AA feature a downward slope at low p T , a local minimum at around 5–7 GeV , and an upward slope with increasing p T . The R AA are also compared in terms of A 1/3 , which is proportional to the nuclear radius. Models including only initial-state nuclear effects fail to reproduce the observed trends, whereas energy loss models reproduce the trends in the region p T > 9.6 GeV .