System evolution of forward-backward multiplicity correlations in a multiphase transport model

The initial geometry effect on forward-backward multiplicity correlations $C(N_f,N_b)$ is studied in relativistic collisions between light nuclei by using a multiphase transport model. It is found that tetrahedron ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ gives a more uniform and symmetrical fireball which produces a more isotropic distribution of final particles after the expansion and evolution, and leads to a small $C(N_f,N_b)$. Forward-backward multiplicity correlation could be taken as a useful probe to distinguish the pattern of $\alpha$-clustered ${}^{16}\mathrm{O}$ in experiments by comparing the neighboring colliding nuclear systems like ${}^{14}\mathrm{N}+{}^{14}\mathrm{N}$ and ${}^{19}\mathrm{F}+{}^{19}\mathrm{F}$.

Figure 1

(a) FB multiplicity correlation coefficient $C(N_f,N_b)$ as a function of centrality in ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200$ GeV as well as ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ collisions at $\sqrt{s_{NN}}=6370$ GeV, (b) FB multiplicity correlation coefficient $C(N_f,N_b)$ as a function of ${\eta }_{\text{gap}}$ in $pp$ collisions at $\sqrt{s_{NN}}=10$, 200, and 5020 GeV.

Figure 2

FB multiplicity correlation coefficient $C(N_f,N_b)$ as a function of impact parameter $b$ for different collision systems (a) ${}^{14}\mathrm{N}+{}^{14}\mathrm{N}$, (b) ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$, and (c) ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ with tetrahedral configuration, (d) ${}^{19}\mathrm{F}+{}^{19}\mathrm{F}$ at $\sqrt{s_{NN}}=6370$ GeV.

Figure 3

The correlation $C(N_f,N_b)$ as a function of ${\eta }_{\text{gap}}$ with window widths $\delta \eta =0.2$ for different collision systems at $\sqrt{s_{NN}}=6370$ GeV.

Figure 4

Sphericity probability distribution in $p+p$ collisions at $\sqrt{s_{NN}}=7$ TeV as well as in ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ collisions for the most central collision at $\sqrt{s_{NN}}=6370$ GeV.

Figure 5

The correlation $C(N_f,N_b)$ as a function of sphericity for different collision systems at $\sqrt{s_{NN}}=6370$ GeV.

Figure 6

The correlation $C(N_f,N_b)$ as a function of ${\varepsilon }_2$ and ${\varepsilon }_3$ for different collision systems at $\sqrt{s_{NN}}=6370$ GeV.