Constraining baryon annihilation in the hadronic phase of heavy-ion collisions via event-by-event fluctuations

Abstract

We point out that the variance of net-baryon distribution normalized by the Skellam distribution baseline, ${\kappa }_2[B-\bar{B}]/⟨B+\bar{B}⟩$, is sensitive to the possible modification of (anti)baryon yields due to $B\bar{B}$ annihilation in the hadronic phase. The corresponding measurements can thus place stringent limits on the magnitude of the $B\bar{B}$ annihilation and its inverse reaction. We perform Monte Carlo simulations of the hadronic phase in Pb-Pb collisions at the LHC via the recently developed subensemble sampler + UrQMD afterburner and show that the effect survives in net-proton fluctuations, which are directly accessible experimentally. The available experimental data of the ALICE Collaboration on net-proton fluctuations disfavors a notable suppression of (anti)baryon yields in $B\bar{B}$ annihilations predicted by the present version of UrQMD if only global baryon conservation is incorporated. On the other hand, the annihilations improve the data description when local baryon conservation is imposed. The two effects can be disentangled by measuring ${\kappa }_2[B+\bar{B}]/⟨B+\bar{B}⟩$, which at the LHC is notably suppressed by annihilations but virtually unaffected by baryon number conservation.

6 pages, 4 figures

References in corpus (5)

• The QCD Equation of State to $\mathcal{O}({\mu }_B^6)$ from Lattice QCD
• Fully integrated transport approach to heavy ion reactions with an intermediate hydrodynamic stage
• Repulsive baryonic interactions and lattice QCD observables at imaginary chemical potential
• Non-thermal p/pi ratio at LHC as a consequence of hadronic final state interactions
• Particlization of an interacting hadron resonance gas with global conservation laws for event-by-event fluctuations in heavy-ion collisions

Cited by in corpus (13)

• Critical lensing and kurtosis near a critical point in the QCD phase diagram in and out-of-equilibrium
• The role of proton-antiproton regeneration in the late stages of heavy-ion collisions
• The imprint of conservation laws on correlated particle production
• Closing in on critical net-baryon fluctuations at LHC energies: cumulants up to third order in Pb$-$Pb collisions
• Centrality dependence of proton and light nuclei yields as a consequence of baryon annihilation in the hadronic phase
• Impact of hadronic interactions and conservation laws on cumulants of conserved charges in a dynamical model
• Cooper-Frye sampling with short-range repulsion
• Density correlations under global and local charge conservation
• Acceptance dependence of factorial cumulants, long-range correlations, and the antiproton puzzle
• Possible origin of HADES data on proton number fluctuations in Au+Au collisions
• Fluctuations of conserved charges in hydrodynamics and molecular dynamics
• The Interplay of Femtoscopic and Charge-Balance Correlations
• Particle spectra in the integrated hydrokinetic model at RHIC Beam-Energy-Scan energies