近日，中国科学技术大学的唐泽波及其研究小组与美国布鲁克海文国家实验室的许长补以及美国肯特州立大学的Chun Yuen Tsang合作并取得一项新进展。经过不懈努力，他们对重离子碰撞中重子和电荷停止的相关性进行研究。相关研究成果已于2024年4月15日在国际知名学术期刊《中国物理C》上发表。

本文利用UrQMD蒙特卡洛模型，深入研究了从氧到铀的多种重离子碰撞的相关性。在UrQMD模型中，价夸克的输运被视为电荷和重子在中速区域停留的主要机制。此外，我们还对⁹⁶₄₀Zr + ⁹⁶₄₀Zr 和 ⁹⁶₄₄Ru + ⁹⁶₄₄Ru等压碰撞进行了详尽的探讨。在重子停止方面，研究发现存在一个电荷停止的普遍趋势，并且这种电荷停止总是超过重子停止。本研究提供了一个价夸克输运的模型基线，以预测相对论性重离子碰撞中速的净电荷和净重子产率。

据悉，重子数在理论上是由重子结构中的价夸克所携带的，这是基于标准量子色动力学图的描述。然而，另一种理论提出了不同的观点，认为重子数是由一种胶子场的非扰动Y形构型所承载的，这种构型在20世纪70年代被称为重子结。不过，这两种理论都尚未得到实验的验证。最近，有研究者提出，通过研究重离子碰撞中速下净电荷和净重子产额的相关性，或许能为寻找重子结提供新的线索。

附：英文原文

Title: Correlations of baryon and charge stopping in heavy ion collisions

Author: Wendi Lv, Yang Li, Ziyang Li, Rongrong Ma, Zebo Tang, Prithwish Tribedy, Chun Yuen Tsang, Zhangbu Xu, Wangmei Zha

Issue&Volume: 2024-04-15

Abstract: Baryon numbers are theorized to be carried by valence quarks in the standard QCD picture of the baryon structure. Another theory proposed an alternative baryon number carrier, a non-perturbative Y-shaped configuration of the gluon field, called the baryon junction in the 1970s. However, neither of these theories has been verified experimentally. Recently, searching for the baryon junction by investigating the correlation of net-charge and net-baryon yields at midrapidity in heavy-ion collisions has been suggested. This paper presents studies of such correlations in collisions of various heavy ions from oxygen to uranium with the UrQMD Monte Carlo model. The UrQMD model implements valence quark transport as the primary means of charge and baryon stopping at midrapidity. Detailed studies are also conducted for isobaric ⁹⁶₄₀Zr + ⁹⁶₄₀Zr and ⁹⁶₄₄Ru + ⁹⁶₄₄Ru collisions. We found a universal trend of charge stopping with respect to baryon stopping and discovered that the charge stopping is always greater than the baryon stopping. This study provides a model baseline in valence quark transport for what is expected in net-charge and net-baryon yields at the midrapidity of relativistic heavy-ion collisions.

DOI: 10.1088/1674-1137/ad243f

Source: http://hepnp.ihep.ac.cn/article/doi/10.1088/1674-1137/ad243f