Relation between baryon number fluctuations and experimentally observed proton number fluctuations in relativistic heavy ion collisions
Relation between baryon number fluctuations and experimentally observed proton number fluctuations in relativistic heavy ion collisions
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DOI：
10.1103/physrevc.86.024904
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发表时间：
2012-05
影响因子：
3.1
通讯作者：
M. Kitazawa;M. Asakawa
中科院分区：
文献类型：
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作者：
M. Kitazawa;M. Asakawa
研究了相对论重离子碰撞中末态质子数和核子数涨落之间的关系。结果表明，在较宽的碰撞能范围内，末态核子的各向同性自旋之间的关联几乎可以忽略。这就导致了在末态下，质子、中子和它们的反粒子的分布函数被分解为二项式分布函数。使用因式分解，我们推导出公式，以确定核子数累积量，这是不是直接的实验观测，从质子数的波动，这是实验观察到的事件，事件分析。通过对奇异重子的简单处理，将核子数累积量进一步推广到重子数累积量。重子数累积量的实验测定使得各种理论研究与实验直接比较成为可能。定量地讨论了非零同位旋密度对该公式的影响。结果表明，在很宽的能量范围内的影响被很好地抑制。
We explore the relation between proton and nucleon number fluctuations in the final state in relativistic heavy ion collisions. It is shown that the correlations between the isospins of nucleons in the final state are almost negligible over a wide range of collision energy. This leads to a factorization of the distribution function of the proton, the neutron, and their antiparticles in the final state with binomial distribution functions. Using the factorization, we derive formulas to determine nucleon number cumulants, which are not direct experimental observables, from proton number fluctuations, which are experimentally observable in event-by-event analyses. With a simple treatment for strange baryons, the nucleon number cumulants are further promoted to the baryon number ones. Experimental determination of the baryon number cumulants makes it possible to compare various theoretical studies directly with experiments. The effects of nonzero isospin density on this formula are addressed quantitatively. It is shown that the effects are well suppressed over a wide energy range.