论文标题
在相对论核的超中性碰撞中剥离中子皮肤
Peeling away neutron skin in ultracentral collisions of relativistic nuclei
论文作者
论文摘要
在沉重的核中，中子和质子的局部密度之间的比率增加了核周围。中子的过量被称为中子皮肤（NS），中子和质子分布的R.M.S半径之间有微妙的差异（$ <0.5 $ 〜fm）。我们表明，$^{208} $ pb中NS的存在导致超中心$^{208} $ pb中的额外的观众中子 - $^{208} $ pb collisisions the Cern sps and LHC。观众中子和质子的产率是在新版本的磨蚀性能蒙特卡洛（Monte Carlo）中用于山脉模型（AAMCC-MST）的收益率，并考虑了观众物质的NS和平衡聚类。尽管超中心碰撞中的观众中子和质子的平均数量无关紧要，但在0,1的事件中，某些观众中子的发射的横截面，... 5观众质子的变化为50--250 \％，具体取决于NS的厚度。这些横截面对计算中的其他参数不太敏感，在LHC的Alice实验中，它们的测量结果将使限制$^{208} $ PB中现有的中子密度参数的种类。
In heavy nuclei the ratio between local densities of neutrons and protons increases towards the nuclear periphery. The excess of neutrons is known as the neutron skin (NS) with a subtle difference ($<0.5$~fm) between the r.m.s radii of the distributions of neutrons and protons. We show that the presence of NS in $^{208}$Pb leads to extra spectator neutrons in ultracentral $^{208}$Pb--$^{208}$Pb collisions at the CERN SPS and LHC. The yields of spectator neutrons and protons were calculated within a new version of Abrasion-Ablation Monte Carlo for Colliders model (AAMCC-MST) taking into account NS and pre-equilibrium clustering of spectator matter. While the average numbers of spectator neutrons and protons in ultracentral collisions vary insignificantly, the cross sections of emission of certain numbers of spectator neutrons in events with 0,1,...5 spectator protons are changed by 50--250\%, depending on the thickness of NS. These cross sections are less sensitive to other parameters in calculations, and their measurements in the ALICE experiment at the LHC will make it possible to restrict the existing variety of neutron density parameterizations in $^{208}$Pb.
