Characterization of nuclear breakup as a function of hard-scattering kinematics using dijets measured by ATLAS in $p$+Pb collisions

Abstract

This Letter analyzes the sensitivity of event geometry estimators to the initial-state kinematics of hard scattering in proton-lead collisions. This analysis uses dijets as a proxy for the parton-parton scattering configuration, correlating it with event geometry estimators, namely the energy deposited in the Zero-Degree Calorimeter and the transverse energy recorded in the Forward Calorimeter in the Pb-going direction. The analysis uses data recorded by the ATLAS detector at the Large Hadron Collider with a nucleon-nucleon center-of-mass energy of 8.16 TeV, corresponding to an integrated luminosity of 56 nb${}^{-1}$. The jets are measured within the pseudorapidity interval $-$2.8 $<$ $\eta$ $<$ 4.5, where positive $\eta$ values correspond to the direction of the proton beam. Results are presented as a function of the Bjorken-$x$ of the parton originating from the proton, $x_p$. Both event geometry estimators are found to be dependent on $x_p$, with the energy deposited in the Zero-Degree Calorimeter about six times less sensitive to $x_p$ compared with the transverse energy deposited in the Forward Calorimeter.

arXiv comment37 pages in total, author list starting page 21, 5 figures, 0 tables, Published in PLB, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2024-11/

References in corpus (16)

• An Introduction to PYTHIA 8.2
• FastJet user manual
• Parton distributions with LHC data
• Production and Integration of the ATLAS Insertable B-Layer
• Small System Collectivity in Relativistic Hadron and Nuclear Collisions
• Identified hadron spectra at large transverse momentum in p+p and d+Au collisions at \sqrts_NN = 200 GeV
• Centrality and rapidity dependence of inclusive jet production in $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV proton-lead collisions with the ATLAS detector
• Parton Distributions in Nucleons and Nuclei
• Suppression of back-to-back hadron pairs at forward rapidity in d+Au Collisions at sqrt(s_NN)=200 GeV
• Constraints on jet quenching in p-Pb collisions at $\sqrt{{\mathbf{s}}_{\mathbf{NN}}}$ = 5.02 TeV measured by the event-activity dependence of semi-inclusive hadron-jet distributions
• Predictions for Cold Nuclear Matter Effects in $p+$Pb Collisions at $\sqrt{s_{{}_{NN}}}=8.16$ TeV
• Nuclear PDFs After the First Decade of LHC Data
• Triple Differential Dijet Cross Section at the LHC
• Global analysis of color fluctuation effects in proton- and deuteron-nucleus collisions at RHIC and the LHC
• Determination of electron-nucleus collision geometry with forward neutrons
• Contribution to differential ${\pi }^0$ and ${\gamma }_{\mathrm{dir}}$ modification in small systems from color fluctuation effects