Report

PUBDB-2023-07316

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Charged-hadron yield measurements in photo-nuclear collisions using 5.02 TeV Pb+Pb data with ATLAS

ATLAS Collaboration (Collaboration author)DESY*

2023

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Please use a persistent id in citations: doi:10.3204/PUBDB-2023-07316

Report No.: ATLAS-CONF-2023-059

Abstract: This note presents the analysis of charged-hadron measurements in photo-nuclear collisions using 1.73 $\mathrm{nb^{-1}}$ of 5.02 TeV Pb+Pb data collected in 2018 by ATLAS. Candidate photo-nuclear events are selected and background events rejected using a combination of zero degree calorimeter, pseudorapidity gap, and tracking information. The yield of charged hadrons as a function of transverse momentum ($p_{\mathrm{T}}$) and pseudorapidity ($\eta$) is measured in these photo-nuclear collisions as a function of charged-particle multiplicity. The results are compared with 0.10 $\mathrm{nb^{-1}}$ of 5.02 TeV p+Pb data collected in 2016 by ATLAS using similar charged-particle multiplicity selections. These photo-nuclear measurements are important for constraining the photon energy distribution and particle production in Monte Carlo models such as DPMJET-III. Additionally, the results are important to test whether such photo-nuclear collisions may produce small droplets of quark-gluon plasma that flow hydrodynamically.

Keyword(s): talk ; heavy ion: scattering ; lead ; photoproduction ; charged particle: multiplicity ; quark gluon: plasma ; photon: energy ; photon: spectrum ; equivalent photon approximation ; calorimeter: forward spectrometer ; trigger ; rapidity: gap ; ATLAS ; droplet ; numerical calculations: Monte Carlo ; flow ; transverse momentum dependence ; rapidity dependence ; hydrodynamics ; background ; hadron: yield ; tracks ; track data analysis ; data analysis method ; experimental results ; 5020 GeV-cms/nucleon ; HEAVYIONS ; Charged-hadron ; yield ; photo-nuclear ; UPC

Note: All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2023-059

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Contributing Institute(s):

1. LHC/ATLAS Experiment (ATLAS)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)

Experiment(s):

1. LHC: ATLAS

Appears in the scientific report 2023

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