Small-x structure of oxygen and neon isotopes as seen by the Large Hadron Collider

Abstract

Results on collisions of ${}^{16}$O nuclei performed at the Relativistic Heavy Ion Collider (RHIC) have been presented for the first time at Quark Matter 2023 by the STAR collaboration. ${}^{16}$O+${}^{16}$O collisions are also expected to take place in the near future at the Large Hadron Collider (LHC) at much higher beam energies. We explore the potential of beam-energy-dependent studies for this system to probe small-$x$ dynamics and QCD evolution. We perform 3+1D IP-Glasma simulations to predict the rapidity dependence of the initial geometry of light-ion collisions, focusing on ${}^{16}$O+${}^{16}$O and ${}^{20}$Ne+${}^{20}$Ne collisions at $\sqrt{s_{\mathrm{NN}}}=70$ GeV and 7 TeV. The choice of ${}^{20}$Ne is motivated by its strongly elongated geometry, which may respond differently to the effect of the high-energy evolution compared to the more spherical ${}^{16}$O. We find that smearing induced by soft gluon production at high energy causes mild variations in the initial-state eccentricities as a function of the collision energy. These effects could be resolved in future experiments and deserve further investigation.

Comments: 4 pages, 3 figures, Contribution to Quark Matter 2023