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Two-particle number and transverse momentum balance function with event topology in pp collisions at s=13  TeV

Subash Chandra Behera1,* and Arvind Khuntia2,†

  • *Contact author: subash.chandra.behera@cern.ch
  • †Contact author: arvind.khuntia@cern.ch
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Phys. Rev. D 114, 036025 – Published 24 August, 2026

DOI: https://doi.org/10.1103/xfgy-dmmb

Abstract

The first study of charge-dependent two-particle differential number (B) and momentum balance functions (P2CD) with respect to an event shape variable, transverse spherocity, is reported. Results are presented from pythia8 and epos-lhc model calculations in proton-proton collisions at s=13  TeV. To distinguish between back-to-back jetlike topologies and isotropic events, low and high transverse spherocity values are chosen. The correlation functions are measured as a function of charged-particle multiplicity classes in relative pseudorapidity (Δη) and relative azimuthal angle (Δϕ) with |η|<2.4 and 0.2<pT<2.0  GeV. A narrowing of the balance function width is observed in Δη and Δϕ from low- to high-multiplicity collisions. Wider balance functions are found in isotropic events as compared to jet-like events. However, for the momentum correlations, a nearly flat dependence is observed with charged particle multiplicity. This study investigates charge conservation mechanisms and their correlations for events classified with jetlike and isotropic topologies. To isolate medium-driven effects, we compare epos-lhc with its hydrodynamic core enabled and disabled and observed narrowing patterns in B and P2CD as a quantitative handle on radial-flow–induced localization of charge-balancing pairs.

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Phys. Rev. D 114, 036025– Published 24 August, 2026
  • Received 27 August 2025
  • Accepted 23 July 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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