Multiplicity fluctuations and correlations in 5.02 TeV p+Pb collisions at zero impact parameter

Abstract

We present a Bayesian method to reconstruct event-by-event multiplicity fluctuations and rapidity correlations in p+Pb collisions at zero impact parameter from minimum-bias data, without assuming any model of the collision dynamics. We test it on Monte Carlo simulations with the Angantyr model, then apply it to ATLAS data on the distribution of charged multiplicity and transverse energy in p+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Fluctuations in $b=0$ collisions are quantum fluctuations which originate mostly from the proton wave function, and therefore have the potential to constrain the subnucleonic structure of the proton. The Angantyr model is found to overestimate fluctuations. In addition, we find that as the rapidity increases (towards the Pb-going side), not only the multiplicity density increases, but also its relative event-by-event fluctuation. This counter-intuitive phenomenon is also observed in simulations with Angantyr, and with the QCD dipole model, where its origin can be traced back to the branching process through which gluons are produced.

arXiv comment15 pages, 10 figures. v2: revised. Discussion of the fluctuating string model and of forward-backward correlations added in Sec.IVC and IVD. The Python code used to fit minimum-bias data (described in Sec. IIIB) is added as an ancillary file

References in corpus (48)

• An Introduction to PYTHIA 8.2
• Computing Quark and Gluon Distribution Functions for Very Large Nuclei
• Glauber Modeling in High Energy Nuclear Collisions
• EPOS LHC : test of collective hadronization with LHC data
• Long-range angular correlations on the near and away side in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• Charged Particle Ratio Fluctuation as a Signal for QGP
• Gluon production in current-nucleus and nucleon-nucleus collisions in a quasi-classical approximation
• Collective flow in p-Pb and d-Pb collisions at TeV energies
• Evidence for collective multi-particle correlations in pPb collisions
• One fluid to rule them all: viscous hydrodynamic description of event-by-event central p+p, p+Pb and Pb+Pb collisions at $\sqrt{s}=5.02$ TeV
• Collective dynamics of the high-energy proton-nucleus collisions
• Centrality dependence of particle production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$= 5.02 TeV
• Evidence of strong proton shape fluctuations from incoherent diffraction
• Evidence for transverse momentum and pseudorapidity dependent event plane fluctuations in PbPb and pPb collisions
• Measurement with the ATLAS detector of multi-particle azimuthal correlations in p+Pb collisions at sqrt(s_NN)=5.02 TeV
• Methods for the Study of Particle Production Fluctuations
• Relativistic hydrodynamics for heavy-ion collisions
• The Angantyr model for Heavy-Ion Collisions in PYTHIA8
• Dynamical initial state model for relativistic heavy-ion collisions
• Fluctuations of particle ratios and the abundance of hadronic resonances
• Eccentric protons? Sensitivity of flow to system size and shape in p+p, p+Pb and Pb+Pb collisions
• Strongly Intensive Quantities
• Multiplicity fluctuations in Au+Au collisions at $\sqrt{s_{NN}}=130$ GeV
• Fluctuations of string tension and transverse mass distribution
• Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton--lead collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02$ TeV with the ATLAS detector
• Color fluctuation effects in proton-nucleus collisions
• Longitudinal dynamics and particle production in relativistic nuclear collisions
• Diffractive and non-diffractive wounded nucleons and final states in pA collisions
• Longitudinal fluctuations of the fireball density in heavy-ion collisions
• Relating centrality to impact parameter in nucleus-nucleus collisions
• The torque effect and fluctuations of entropy deposition in rapidity in ultra-relativistic nuclear collisions
• Bayesian inference of the fluctuating proton shape
• Fluctuations of anisotropic flow in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector
• Long range rapidity correlations as seen in the STAR experiment
• Reconstructing the impact parameter of proton-nucleus and nucleus-nucleus collisions
• Measurement of forward-backward multiplicity correlations in lead-lead, proton-lead and proton-proton collisions with the ATLAS detector
• Entropy production in pp and Pb-Pb collisions at energies available at the CERN Large Hadron Collider
• Relative particle yield fluctuations in Pb-Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=2.76$ TeV
• Multiparticle correlation studies in pPb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 8.16 TeV
• A simple model for rapidity fluctuations in the initial state of ultra-relativistic heavy-ion collisions
• Bayesian approach to long-range correlations and multiplicity fluctuations in nucleus-nucleus collisions
• Hidden asymmetry and long range rapidity correlations
• Centrality fluctuations and decorrelations in heavy-ion collisions
• Fluctuations of the multiplicity of produced particles in onium-nucleus collisions
• Neutral to charged kaon yield fluctuations in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76TeV
• Gluon density fluctuations in dilute hadrons
• Longitudinal correlations from fluctuating strings in Pb-Pb, p-Pb, and p-p collisions
• Pictures of Particle Production in Proton-Nucleus Collisions

Cited by in corpus (4)

• Non-Gaussian transverse momentum fluctuations from impact parameter fluctuations
• Accessing the speed of sound in relativistic ultracentral nucleus-nucleus collisions using the mean transverse momentum
• The size of the quark-gluon plasma in ultracentral collisions: impact of initial density fluctuations on the average transverse momentum
• Multiplicity fluctuations and rapidity correlations in ultracentral proton-nucleus collisions