Impact of resonance decays on critical point signals in net-proton fluctuations

Abstract

The non-monotonic beam energy dependence of the higher cumulants of net-proton fluctuations is a widely studied signature of the conjectured presence of a critical point in the QCD phase diagram. In this work we study the effect of resonance decays on critical fluctuations. We show that resonance effects reduce the signatures of critical fluctuations, but that for reasonable parameter choices critical effects in the net-proton cumulants survive. The relative role of resonance decays has a weak dependence on the order of the cumulants studied with a slightly stronger suppression of critical effects for higher-order cumulants.

Critical behavior of the bulk viscosity in QCD

“…We assume that the singular part of the QCD entropy density is proportional to the Ising entropy density, s sing (e, n) = As Is ( (e, n), ψ(e, n)). A common assumption is that the images of the r and h axes in the QCD phase diagram are approximately orthogonal, and that the Ising temperature axis is almost aligned with the QCD chemical potential axis 1 , ∂ /∂e 0 [8,9,33]. This implies that…”

“…wherew,ρ and α 1,2 are parameters. Most of the work in the existing literature [8,9,33] assumes that α 1 0 and α 2 π/2. We will discuss this assumption in more detail below, but for now we will assume that α 1 = 0 and α 2 = π/2.…”

“…VI that this is due to the fact that in equ. (33) we have neglected the coupling of the order parameter to the momentum density of the fluid. The coupling γ R ± a n was determined in equ.…”

Influence of Backside Energy Leakages from Hadronic Calorimeters on Fluctuation Measures in Relativistic Heavy-Ion Collisions

“…Fluctuation measures are considered to be an important tool in the search of the possible critical point of the strongly interacting matter. However, fluctuation quantities are sensitive to various effects along with the critical behavior [1][2][3][4] such as volume fluctuations [5,6], resonance decays [7], beam and target material impurities [8] and detector inefficiencies.…”

“…Two MC datasets were generated with the GEANT4 [11] PSD simulation for studying the energy leakage influence on different systems: 100,000 events of 150A GeV/c 7 Li + 9 Be SHIELD MC [12] and 40,000 events of 150A GeV/c 40 Ar + 45 Sc EPOS 1.99 MC [13]. 7 Li was chosen instead of experimentally used 7 Be as the first one is stable and can be simulated by SHIELD MC. It was possible to compare two completely different MC generators as the studied effect was purely detector based.…”