论文标题
Deuteron在D+AU超外五碰撞中的独家$ J/ψ$ Photoductuction of Star
Exclusive $J/ψ$ photoproduction off deuteron in d+Au ultra-peripheral collisions at STAR
论文作者
论文摘要
Gluon密度及其在核内的分布以及核内有界核的Parton修饰，是核和粒子物理学中的一些主要存在问题。近年来，重离子的超外碰撞（UPC）提供了一种探测Gluon密度的新方法，该密度基于相干衍射矢量 - 媒体生产，例如$ J/ψ$ Meson。对于重离子，例如Pb，发现Gluon密度通过UPC $ J/ψ$测量得到了显着抑制，这表明重核中具有很强的gluon阴影效果。在此分析中，我们旨在研究Star实验采集的一组独特的数据，其中$ j/ψ$介子在没有产生的其他粒子的情况下从杜特隆目标上进行了光增生，除了迪特隆或其分手产品。还研究了通过检测束相当中子的核心量响应于Deuteron解离的响应，并提供了有关基础物理过程的其他信息。 $ J/ψ$光生生产的横截面在光子 - deuteron系统中进行测量，以光子 - 核中心质量$ W \ sim25〜 \ rm {gev} $以及动量传递$ t $ t $依赖性截面，$dσ/dt $。数据表明，与杜特隆的Hulthen电荷密度分布相比，GLUON密度分布更大。
Gluon density and its distributions inside nuclei and the parton modification of bounded nucleons inside a nucleus, are some of the main standing problems in nuclear and particle physics. In recent years, ultra-peripheral collisions (UPC) of heavy ions have provided a new way of probing the gluon density, which is based on coherent diffractive vector-meson productions, e.g., $J/ψ$ meson. For heavy ions, e.g., Pb, the gluon density is found to be significantly suppressed through the UPC $J/ψ$ measurement, suggesting a strong gluon shadowing effect in heavy nuclei. In this analysis, we aim to look at a unique set of data taken by the STAR experiment, where $J/ψ$ mesons are photoproduced off the deuteron target with no other particle produced, except for the deuteron or its breakup products. The Zero Degree Calorimeter response with respect to the deuteron dissociation by detecting a beam-rapidity neutron is also investigated and provides additional information about the underlying physics process. The cross section of $J/ψ$ photoproduction in the photon-deuteron system is measured at the photon-nucleon center-of-mass energy $W\sim25~\rm{GeV}$, as well as the momentum transfer $t$ dependence cross section, $dσ/dt$. Data suggests a wider gluon density distribution than the Hulthen charge density distribution in deuteron.
