Baryon number conservation and the cumulants of the net proton distribution

We discuss the modification of the cumulants of the net baryon and net proton distributions due to the global conservation of baryon number in heavy-ion collisions. Corresponding probability distributions and their cumulants are derived analytically. We show that the conservation of baryon number results in a substantial decrease of higher order cumulants. Based on our studies, we propose an observable that is insensitive to the modifications due to baryon number conservation.

Figure 1

Ratios of odd- and even-order cumulants as a function of the fraction of measured baryons, $p$. The parameters are $B=300$, $\langle N_B\rangle =400$, and $\langle N_{\overline{B}}\rangle =100$.

Figure 2

Ratios of odd- and even-order cumulants as a function of the fraction of measured baryons, $p$, in the range of values which are of experiment interest. The parameters are $B=300$, $\langle N_B\rangle =400$, and $\langle N_{\overline{B}}\rangle =100$.

Figure 3

The ratios $R_{3,1}$, $R_{5,1}$, and $D$ as a function of temperature in the Polyakov loop-extended quark-meson model. The calculations are performed along the line of fixed ${\mu }_B/T\approx 0.5$. $T_{pc}$ is the crossover temperature at the corresponding chemical potential.