^(208)Pb中子皮厚度与核物质对称能  

Neutron skin thickness in ^(208)Pb and symmetry energy of nuclear matter

作　　者：董建敏[1] 宗瑶瑶 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]兰州大学核科学与技术学院,兰州730000

出　　处：《中国科学：物理学、力学、天文学》2016年第1期204-209,共6页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(批准号:11405223;11175219;10975190;11275271);国家重点基础研究发展计划项目(编号:2013CB834405)资助

摘　　要：^(208)Pb中子皮厚度△R_(np)的准确知识对于核物理及天体物理的众多研究领域具有深远的影响,然而目前宇称半径实验(PREX)仍未对中子皮厚度△R_(np)给出很好的约束.基于中子皮厚度△R_(np)和J-a_(sym)之间的高度线性关联,本文总结了我们最近的一些研究结果,采用一种当前更加可行的方法来约束△R_(np),其中J,a_(sym)分别为核物质饱和点处及^(208)Pb的对称能(系数),相比于PREX中的宇称破缺非对称对度A_(PV),J-a_(sym)可以通过大量的核质量及核衰变能实验数据可靠容易且廉价地提取.同时,J-a_(sym)也很好地约束了对称能在饱和密度附近的密度依赖性.最后,基于"tomoscan"方法,提出在强子散射测量^(208)Pb中子皮厚度实验中,人们只需考虑半径大于R_m=(7.61±0.04)fm处的核子密度分布,而无需关注其内部结构.Accurate knowledge about the neutron skin thickness △Rnp in 208pb has far-reaching influence on different communities of nuclear physics and astrophysics. The novel Lead Radius Experiment （PREX）, however, did not yield stringent constraint on the △Rnp recently. We summed our recent works that in particular we employ a more practicable strategy currently to probe the neutron skin thickness of 208pb based on a high linear correlation between the △Rnp and J - asym, where J and asym are the symmetry energy （coefficient） of nuclear matter at saturation density and of 208pb. Compared with the parity-violating asymmetry Apv in the PREX, the reliably experimental information on the J - asym is much more easily available attributed to a wealth of measured nuclear masses and on decay energies. In addition, the density dependence of the symmetry energy is also well constrained with the J - asym. Finally, based on a ＇tomoscan＇ method, we proposed that one just needs to measure the nucleon densities in 208pb starting from Rrn = （7.61 ± 0.04） fm to obtain the △ Rnp in hadron scattering experiments, regardless of its interior profile.

关 键 词：中子皮 对称能 核物质 

分 类 号：O571[理学—粒子物理与原子核物理]