Charged-hadron and identified-hadron ($K_{\mathrm{S}}^0$, $\Lambda$, ${\Xi }^{-}$) yield measurements in photo-nuclear Pb+Pb and $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with ATLAS

Abstract

This paper presents the measurement of charged-hadron and identified-hadron ($K_{\mathrm{S}}^0$, $\Lambda$, ${\Xi }^{-}$) yields in photo-nuclear collisions using 1.7 $\mathrm{n}{\mathrm{b}}^{-1}$ of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV Pb+Pb data collected in 2018 with the ATLAS detector at the Large Hadron Collider. Candidate photo-nuclear events are selected using a combination of tracking and calorimeter information, including the zero-degree calorimeter. The yields as a function of transverse momentum and rapidity are measured in these photo-nuclear collisions as a function of charged-particle multiplicity. These photo-nuclear results are compared with 0.1 $\mathrm{n}{\mathrm{b}}^{-1}$ of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV $p$+Pb data collected in 2016 by ATLAS using similar charged-particle multiplicity selections. These photo-nuclear measurements shed light on potential quark-gluon plasma formation in photo-nuclear collisions via observables sensitive to radial flow, enhanced baryon-to-meson ratios, and strangeness enhancement. The results are also compared with the Monte Carlo DPMJET-III generator and hydrodynamic calculations to test whether such photo-nuclear collisions may produce small droplets of quark-gluon plasma that flow collectively.

51 pages in total, author list starting page 34, 17 figures, 0 tables, published in Phys. Rev. C. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2024-02/

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• Glauber Modeling in High Energy Nuclear Collisions
• The Physics of Ultraperipheral Collisions at the LHC
• Coalescence Models For Hadron Formation From Quark Gluon Plasma
• Imaging the nucleus with high-energy photons
• Modified Hagedorn formula including temperature fluctuation - Estimation of temperatures at RHIC experiments -

Cited by in corpus (1)

• Measurement of D${}^0$ meson photoproduction in ultraperipheral heavy ion collisions