Effects of hadronic mean-field potentials on Hanbury-Brown–Twiss correlations in relativistic heavy-ion collisions

With the parameters fitted by the particle multiplicity, the energy density at chemical freeze-out, and the charged particle elliptic flow, we have studied the effects of the hadronic mean-field potentials on the Hanbury-Brown and Twiss (HBT) correlation in relativistic heavy-ion collisions based on a multiphase transport model. The hadronic mean-field potentials are found to delay the emission time of the system and lead to large HBT radii extracted from the correlation function. Effects on the energy dependence of $R_o^2-R_s^2$ and $R_o/R_s$ as well as the eccentricity of the emission source are discussed. The HBT correlations can also be useful in understanding the mean-field potentials of protons, kaons, and antiprotons as well as baryon-antibaryon annihilations.

Figure 1

Pseudorapidity distributions of charged particles in central Au+Au collisions at $\sqrt{s_{NN}}=39$, 27, 19.6, 11.5, and 7.7 GeV from the string-melting AMPT model, compared with the PHOBOS data for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=19.6$ GeV and centrality of $0-6\%$ taken from Refs. [38, 39].

Figure 2

Time evolution of the energy density (left column), the reduced baryon density (middle column), and the reduced antibaryon density (right column) in the central region of the hadronic phase in midcentral ($20-30\%$) Au+Au collisions at $\sqrt{s_{NN}}=7.7$, 11.5, 19.6, 27, and 39 GeV.

Figure 3

Transverse momentum ($p_T$) dependence of charged hadron elliptic flow ($v_2$) at midpseudorapidities ($\left|\eta \right|<1.0$) in midcentral ($20-30\%$) Au+Au collisions at $\sqrt{s_{NN}}=7.7$ to 39 GeV, compared with the STAR data taken from Ref. [41].

Figure 4

Distributions of hadron freeze-out time with (right) or without (left) mean-field potentials in Au+Au collisions at $\sqrt{s_{NN}}=7.7$, 11.5, 19.6, 27, and 39 GeV.

Figure 5

HBT correlation of charged pions at midpseudorapidities with and without mean-field potentials in central Au+Au collisions at $\sqrt{s_{NN}}=7.7$ GeV.

Figure 6

Collision energy dependence of $R_o^2-R_s^2$ and $R_o/R_s$ extracted from freeze-out charged pions with and without mean-field potentials in central Au+Au collisions compared with those extracted from STAR measurements [46].

Figure 7

Freeze-out eccentricity ${\epsilon }_F^{}$ extracted from the HBT correlation of charged pions with and without mean-field potentials as a function of the c.m. energy $\sqrt{s_{NN}}$ in midcentral Au + Au collisions compared with those extracted from STAR measurements [46].

Figure 8

Proton-proton HBT correlation (left) and charged kaon HBT correlation (right) at midpseudorapidities with and without mean-field potentials in central Au+Au collisions at $\sqrt{s_{NN}}=7.7$ GeV.

Figure 9

Proton-antiproton HBT correlation with and/or without mean-field potentials and baryon-antibaryon annihilations in midcentral Au+Au collision at $\sqrt{s_{NN}}=39$ GeV.