Effects of nuclear charge fluctuations on dilepton photoproduction

Guansong Li,Kai Zhou,Baoyi Chen

Figure 4. Relative standard deviation $\tfrac{\sqrt{\langle {\left(X-\langle X\rangle \right)}^{2}\rangle }}{\langle X\rangle }$ for dilepton photoproduction due to the uncertainties of impact parameter as a function of invariant mass at RHIC $\sqrt{{s}_{{NN}}}=200\,\mathrm{GeV}$ Au-Au collisions. The impact parameter locates randomly at 10 < b < 11 fm. The rapidity cut of dileptons is $| {y}_{{e}^{+}{e}^{-}}| \lt 1$. The nuclear charge distribution is taken to be the smooth situation in figure 1. X $\,\equiv {\rm{d}}{N}/{{\rm{d}}{M}}_{{e}^{+}{e}^{-}}$ is the dilepton spectrum.