Helenius Ilkka, Paukkunen Hannu, Eskola Kari J
Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, 223 62 Lund, Sweden.
Institute for Theoretical Physics, Tübingen University, Auf der Morgenstelle 14, 72076 Tübingen, Germany.
Eur Phys J C Part Fields. 2017;77(3):148. doi: 10.1140/epjc/s10052-017-4709-9. Epub 2017 Mar 9.
A well-established observation in nuclear physics is that in neutron-rich spherical nuclei the distribution of neutrons extends farther than the distribution of protons. In this work, we scrutinize the influence of this so called neutron-skin effect on the centrality dependence of high-[Formula: see text] direct-photon and charged-hadron production. We find that due to the estimated spatial dependence of the nuclear parton distribution functions, it will be demanding to unambiguously expose the neutron-skin effect with direct photons. However, when taking a ratio between the cross sections for negatively and positively charged high-[Formula: see text] hadrons, even centrality-dependent nuclear-PDF effects cancel, making this observable a better handle on the neutron skin. Up to 10% effects can be expected for the most peripheral collisions in the measurable region.
核物理学中一个已被充分证实的观察结果是，在富含中子的球形原子核中，中子的分布比质子的分布延伸得更远。在这项工作中，我们仔细研究了这种所谓的中子皮效应对高横动量直接光子和带电强子产生的中心度依赖性的影响。我们发现，由于估计的核部分子分布函数的空间依赖性，用直接光子明确揭示中子皮效应将具有挑战性。然而，当取带负电和带正电的高横动量强子的截面之比时，即使与中心度相关的核部分子分布函数效应也会相互抵消，使得这个可观测量能更好地处理中子皮问题。在可测量区域内，对于最外围的碰撞，预计会有高达10%的效应。
