排序方式: 共有86条查询结果,搜索用时 15 毫秒
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在最近几年我们通过使用同位旋相关的量子分子动力学模型 (IQMD)系统的研究了同位旋相关的平均场和介质中核子 核子 (N N)碰撞截面对中能重离子碰撞 (HIC)中碎裂和耗散的同位旋效应。我们发现原子核阻止R和Qzz,中等质量碎片多重性Nimf和质子(中子 )发射数Np(Nn)敏感的依赖于介质中N N碰撞截面的同位旋效应 ,而弱的依赖于同位旋相关的平均场 (对称势 ) ,这些物理量作为提取相对高能范围缺中子系统的同位旋相关介质中N N碰撞截面的探针。我们也可以通过相对低能区到 1 5 0MeV/u的前平衡核子发射中质比来提取关于对称势的知识和讨论它的同位旋依赖性。 相似文献
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评述了天体物理中暗物质的发现以及标准模型所面临的问题,综述了解决这些问题及标准模型之外可能出现的新物理与暗物质的联系。介绍了暗物质粒子选择条件和可能的暗物质粒子的候选者;对圆柱形暗物质表面密度与星系和星系团暗物质晕的晕核半径的关系进行了讨论,与其他模型进行了比较,得出暗物质晕的特征半径r*的暗物质表面密度分布不是一个普适量;并叙述了近几年暗物质研究中提出的新理论模型-Hidden dark matter,最后叙述了中国暗物质实验探测研究的进展,2016年底DAMPE的第一批数据有可能给出;中国锦屏地下实验室(CJPL)的CDEX和PandaX合作组的第一期实验没有发现暗物质粒子存在的信号,期待他们下期的实验。A review of the evidence of the dark matter found in universe and the problems faced by the standard model. To address these issues as well as the possible relationship between the new physics beyond the standard model and dark matter, and given the selection condition of dark matter and possible candidates of the weakly-interacting massive particles (WIMPs). The correlation between the column surface density and the halo core radius of the dark matter halos of galaxies and cluster of galaxies is discussed, and the other models are compared. We find that the surface density within the halo characteristic radius r* is not an universal quantity; The new model (hidden dark matter)proposed in the study of dark matter is described. At last, the research progress of dark matter experiment in China is commented. At the end of 2016, the first batch of DAMPE data may be given;No significant excess events of WIMPS were found in the first stage of both the CDEX and PandaX experiments located in the China Jinping Underground Laboratory(CJPL). Look forward to their the next stage of these experiments in CJPL. 相似文献
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In this paper we discuss the properties of the general covariant angular momentum of a five-dimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of the inflationary RS model are all zero while the others are non-zero, which agrees with the results from ordinary RS model. 相似文献
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兰州冷却储存环上可开展的强子物理研究 总被引:1,自引:0,他引:1
介绍了当前强子物理的研究现状和兰州冷却储存环的能量特点,以及国内强子物理专家的分析和建议。在兰州冷却储存环上,可利用中能轻离子束核反应产生强子激发态研究强子内部夸克态的结构和性质、强子性质随核环境的变化和手征对称破缺与部分恢复。尤其是通过兰州冷却储存环上限能区附近的P+P反应,研究奇异夸克的不对称性和形状因子,寻找超子激发态和pentaquark的实验证据,发现双重子态的实验事例。 According to both the development on badrons physics and the aspect of Lanzhou cooling storage ring (CSR) and based on the analysis and propositions given by experts in China, we propose some hadrons physics program at CSR. The hadron spectroscopy produced in light nucleus collisions at CSR used to probe the quark and gluon structure of hadrons, to study the modification of the hadron properties in nuclear matter and to investigate the spontaneous breaking of the chiral symmetry and its partial restoration. Especially, the proton-proton collisions at beam energies per proton below 2.8 GeV at CSR should be used to measure the strangeness asymmetry and strange form lector, to probe the existence of hyperon and pentaquarks and to find the evidence for the existence of dibaryon. 相似文献
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We study the average property of the isospin effects of reaction mechanism induced by neutron-halo nuclei within the isospin-dependent quantum molecular dynamics model. We find that the extended neutron density distribution for the neutron-halo projectile brings an important isospin effect into the reaction mechanism, which induces the decrease of nuclear stopping R; however, it induces the obvious increases of the neutron-proton ratio of nucleon emissions (n/p)nucl for all of the beam energies in this work, compared to the same mass stable colliding system. 相似文献
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利用同位旋相关的量子分子动力学模型研究了中能重离子碰撞中同位旋分馏过程.研究结果表明自由粒子中质比与碎片中质比的比值即同位旋分馏强度灵敏地依赖于对称势,而对同位旋相关核子–核子碰撞截面的依赖很弱.同位旋分馏对对称势的灵敏主要来自于气相部分,而液相部分对对称势不够灵敏.气相部分灵敏地依赖于对称势是直接造成同位旋分馏强度对对称势灵敏的主要原因.同时还讨论了各种液相部分的取法,其结果表明不同取法对以上结论的影响不大.因此理论结果与实验数据可以直接比较从而提取对称势的知识.并对引发同位旋分馏的动力学的起因进行了分析和讨论. 相似文献
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中能重离子碰撞中的中子(质子)发射的同位旋效应 总被引:1,自引:0,他引:1
利用同位旋相关的量子分子动力学,对中能重离子碰撞过程中的中子和质子发射的同位旋效应进行了分析.计算结果表明在有动量相关作用条件下,在很宽的能量和碰撞参数范围内,缺中子碰撞系统的中子(质子)发射数强烈地依赖于同位旋相关的核子–核子碰撞截面,而较弱地依赖于对称势.在对丰中子碰撞系统的研究中,上述规律减弱.这样就可以通过实验上对缺中子碰撞系统的中子(质子)发射数的探测,来提取介质中同位旋相关核子–核子碰撞截面的知识. 相似文献
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