论文标题
初始密度波动对$ \ sqrt {s_ {nn}} $ = 7.7 GEV的au + au碰撞中累积的影响
Effects of Initial Density Fluctuations on Cumulants in Au + Au Collisions at $\sqrt{s_{NN}}$ = 7.7 GeV
论文作者
论文摘要
在超级量子分子动力学（URQMD）模型中，初始密度波动对$ \ sqrt {s_ {s_ {nn}} $ = 7.7 GEV的Au + au碰撞中净质子多样性分布的累积的影响，通过对最初的$ d _ = 7.7 GEV进行了调查。发现最初的密度波动随着$ d _ {\ rm min} $从1.6 fm减少到1.0 fm的减少，并且$ d _ {\ rm min} $的影响对净 - 果子数量在狭窄的pseudorapition窗口中的净值波动的大小波动（$ $ $ us feudibible）在net-proton数量上波动（$ 4）的影响。在宽阔的假性窗口（$δη\ geq $ 4）上，当初始密度波动增加时，累积比率扩大，较小的$ d _ {\ rm min} $较小的值，并且这种增强与在核平均核均值电位的存在下观察到的增强功能相当。此外，增强的累积物在与较大影响参数的碰撞中更为明显。目前的工作表明，在宽阔的伪造窗口中，累积物上的初始密度波动的指纹清晰可见，而这并不明显，因为伪造性窗口变得狭窄。
Within the ultrarelativistic quantum molecular dynamics (UrQMD) model, the effect of initial density fluctuations on cumulants of the net-proton multiplicity distribution in Au + Au Collisions at $\sqrt{s_{NN}}$ = 7.7 GeV was investigated by varying the minimum distance $d_{\rm min}$ between two nucleons in the initialization. It was found that the initial density fluctuations increased with the decrease of $d_{\rm min}$ from 1.6 fm to 1.0 fm, and the influence of $d_{\rm min}$ on the magnitude of the net-proton number fluctuation in a narrow pseudorapidity window ($Δη\leq$ 4) was negligible even if it indeed affected the density evolution during the collision. At a broad pseudorapidity window ($Δη\geq$ 4), the cumulant ratios were enlarged when the initial density fluctuations were increased with the smaller value of $d_{\rm min}$, and this enhancement was comparable to that observed in the presence of the nuclear mean-field potential. Moreover, the enhanced cumulants were more evident in collisions with a larger impact parameter. The present work demonstrates that the fingerprint of the initial density fluctuations on the cumulants in a broad pseudorapidity window is clearly visible, while it is not obvious as the pseudorapidity window becomes narrow.
