System size and event shape dependence of particle-identified balance functions in proton-proton collisions at $\sqrt{s}=13$ TeV using PYTHIA 8 and EPOS models

Abstract

We investigate charge balance functions for pion, kaon, and proton pairs in proton-proton (pp) collisions at $\sqrt{s}=13$ TeV using Monte Carlo models, PYTHIA8 and EPOS-LHC, with transverse spherocity to classify event topology and charged-particle multiplicity to select system size. Simulations with PYTHIA8 and EPOS-LHC reveal that balance-function widths in rapidity and azimuthal angle depend on multiplicity and event shape. In PYTHIA8, widths decrease monotonically with multiplicity, consistent with local charge conservation in a fragmentation-dominated scenario. In contrast, the EPOS-LHC model, especially when using the core corona implementation, exhibits a more intricate response, where the combined effects of hydrodynamic radial flow and longitudinal diffusion result in narrower azimuthal correlations and broader rapidity correlations. These features are characteristic signatures of collective dynamics, similar to those observed in heavy-ion collisions. Events with low spherocity, which are jet-like in nature, exhibit significantly narrower balance function widths compared to isotropic events with high spherocity, illustrating that event-shape selection provides clear sensitivity to the underlying dynamics of particle production in pp collisions. The species dependence and event-shape sensitivity of the balance-function widths provide information about the hadronization dynamics and collectivity in small systems. These results demonstrate that multidimensional, particle species dependent balance function measurements can disentangle the underlying mechanisms of charge correlations and medium-like behavior in high-multiplicity pp collisions.

14 pages, 8 figures

References in corpus (46)

• FastJet user manual
• Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
• Quark Gluon Plasma an Color Glass Condensate at RHIC? The perspective from the BRAHMS experiment
• The PHOBOS Perspective on Discoveries at RHIC
• EPOS LHC : test of collective hadronization with LHC data
• Observation of Long-Range Near-Side Angular Correlations in Proton-Proton Collisions at the LHC
• Long-range angular correlations on the near and away side in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• Observation of Associated Near-side and Away-side Long-range Correlations in sqrt(s_NN)=5.02 TeV Proton-lead Collisions with the ATLAS Detector
• Evidence for collectivity in pp collisions at the LHC
• Observation of long-range elliptic anisotropies in $\sqrt{s}=$13 and 2.76 TeV $pp$ collisions with the ATLAS detector
• Color reconnection and flow-like patterns in pp collisions
• Measurement of long-range near-side two-particle angular correlations in pp collisions at sqrt(s) = 13 TeV
• Clocking hadronization in relativistic heavy ion collisions with balance functions
• Long-range and short-range dihadron angular correlations in central PbPb collisions at a nucleon-nucleon center of mass energy of 2.76 TeV
• Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for $pp$ collisions at $\sqrt{s}=5.02$ and $13$ TeV and $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector
• Elliptic flow of charm and strange hadrons in high-multiplicity pPb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$ 8.16 TeV
• Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV
• Hierarchy of azimuthal anisotropy harmonics in collisions of small systems from the Color Glass Condensate
• Charge correlations using the balance function in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Core-corona procedure and microcanonical hadronization to understand strangeness enhancement in proton-proton and heavy ion collisions in the EPOS4 framework
• Multiplicity and transverse momentum evolution of charge-dependent correlations in pp, p-Pb, and Pb-Pb collisions at the LHC
• Femtoscopy in Relativistic Heavy Ion Collisions and its Relation to Bulk Properties of QCD Matter
• Identifying the Charge Carriers of the Quark-Gluon Plasma
• Overview of high-density QCD studies with the CMS experiment at the LHC
• The Role of Baryon Number Conservation in Measurements of Fluctuations
• General Charge Balance Functions, A Tool for Studying the Chemical Evolution of the Quark-Gluon Plasma
• Charge Balance Functions for Heavy-Ion Collisions at LHC Energies
• Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV
• Kinematic dependence of azimuthal anisotropies in $p$$+$Au, $d$$+$Au, ${}^3$He+Au at $\sqrt{s_{{}_{NN}}}$ = 200 GeV
• Two particle differential transverse momentum and number density correlations in p-Pb and Pb-Pb at the LHC
• Novel observables for exploring QCD collective evolution and quantum entanglement within individual jets
• Event Shape Engineering and Multiplicity dependent Study of Identified Particle Production in proton+proton Collisions at $\sqrt{s}$= 13 TeV using PYTHIA8
• Measurement of long-range two-particle azimuthal correlations in $Z$-boson tagged $pp$ collisions at $\sqrt{s}=8$ and 13 TeV
• Two-particle azimuthal correlations in $\gamma$p interactions using pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV
• CMS PYTHIA 8 colour reconnection tunes based on underlying-event data
• Differential two-particle number and momentum correlations with the AMPT, UrQMD, and EPOS models in Pb-Pb collisions at $\sqrt{{\text{s}}_{{}_{\mathrm{NN}}}}$= 2.76 TeV
• Observation of enhanced long-range elliptic anisotropies inside high-multiplicity jets in pp collisions at $\sqrt{s}$ = 13 TeV
• General balance functions of identified charged hadron pairs of $(\pi ,\mathrm{K},\mathrm{p})$ in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Boost Invariance and Multiplicity Dependence of the Charge Balance Functionin ${\pi }^{+}p$ and $K^{+}p$ Collisions at $\sqrt{s}=22$ GeV/c
• Light-flavor particle production in high-multiplicity pp collisions at $\sqrt{\text{s}}=13$ TeV as a function of transverse spherocity
• Heavy ion collisions: Correlations and Fluctuations in particle production
• Measurement of the Sensitivity of Two-Particle Correlations in $pp$ Collisions to the Presence of Hard Scatterings
• Elliptic flow splittings in the Polyakov-looped Nambu-Jona Lasinio transport model
• Multiplicity and transverse momentum dependence of charge-balance functions in pPb and PbPb collisions at LHC energies
• Baryon correlations in Pythia
• Measurements of differential two-particle number and transverse momentum correlation functions in pp collisions at $\sqrt{\text{s}}$ = 13 TeV