费米能区中心重离子碰撞中的新同位旋效应

Isospin influence on dynamical production of Intermediate Mass Fragments at Fermi Energies

The Intermediate Mass Fragments emission probability from Projectile-Like Fragment break-up in semi-peripheral reactions has been measured in collisions of $^{124}$Xe projectiles with two different targets of $^{64}$Ni and $^{64}$Zn at the laboratory energy of 35 \amev. The two colliding systems differ only for the target atomic number Z and, consequently, for the Isospin $N/Z$ ratio. An enhancement of Intermediate Mass Fragments production for the neutron rich $^{64}$Ni target, with respect to the $^{64}$Zn, is found. In the case of one Intermediate Mass Fragment emission, the contributions o…

Isospin dependent hybrid model for studying isoscaling in heavy ion collisions around the Fermi energy domain

Investigation of observables from nuclear multifragmentation reactions depending on isospin led to the development of a hybrid model. The mass and charge distribution as well as isotopic distribution was studied using this model for $^{112}$Sn+$^{112}$Sn reaction as well as $^{124}$Sn+$^{124}$Sn reactions at different energies. The agreement of the results obtained from the model with those from experimental data confirms the accuracy of the model. Isoscaling coefficients were extracted from these observables which can throw light on the symmetry energy coefficient. Another important facet of …

中能重离子碰撞中的同位旋弛豫时间

Isospin relaxation time in heavy-ion collisions at intermediate energies

利用一个与同位旋相关的输运模型，研究了中能重离子碰撞中重残留物的同位旋和动量弛豫时间。结果表明，只有在入射能量低于费米能时，才能达到化学平衡或热平衡，然后才能在重剩余物中发展出动力学不稳定性。在束流能量低于（高于）费米能时，同位旋弛豫时间比动量弛豫时间短（长）。

费米能下的准弹核碎裂与同位旋平衡：弹核-靶核接触时间更长的迹象？

Quasiprojectile breakup and isospin equilibration at Fermi energies: an indication of longer projectile-target contact times?

本研究利用INDRA-FAZIA装置实验数据与AMD-GEMINI++模拟，发现费米能下Ni核碰撞的准弹核碎裂道同位旋弛豫程度更高，表明其弹靶接触时间更长。

First results from the INDRA-FAZIA apparatus on isospin diffusion in $^{58,64}$Ni+$^{58,64}$Ni systems at Fermi energies

An investigation of the isospin equilibration process in the reactions $^{58,64}$Ni+$^{58,64}$Ni at two bombarding energies in the Fermi regime ($32\,$MeV/nucleon and $52\,$MeV/nucleon) is presented. Data have been acquired during the first experimental campaign of the coupled INDRA-FAZIA apparatus in GANIL. Selecting from peripheral to semi-central collisions, both the neutron content of the quasiprojectile residue and that of the light ejectiles coming from the quasiprojectile evaporation have been used as probes of the dynamical process of isospin diffusion between projectile and target for…

中能半周边$^{58}Ni$ + $^{197}Au$碰撞中的同位旋扩散（II）：动力学模拟

Isospin diffusion in semi-peripheral $^{58}Ni$ + $^{197}Au$ collisions at intermediate energies (II): Dynamical simulations

在入射能量为52-74 A MeV的范围内，通过考虑对称的$^{58}Ni$ + $^{58}Ni$和不对称的$^{58}Ni$ + $^{197}Au$，研究了费米能级以上的半周边碰撞中的同位旋效应.采用两种不同参数化的对称能量项的微观输运模型来研究平衡前排放和N/Z扩散过程的同位素含量。模拟还与INESTRA阵列获得的实验数据进行了比较，并带来了在Ni + Au碰撞中观察到的同位旋平衡程度的信息。一个更好的数据和模拟之间的整体协议时，获得使用的对称项与核密度线性增加。

费米能区 $^{40,48}$Ca$+^{40,48}$Ca 实验数据的同位旋扩散：与输运模型计算的直接比较

Isospin diffusion from $^{40,48}$Ca$+^{40,48}$Ca experimental data at Fermi energies: Direct comparisons with transport model calculations

本文通过对比 35 MeV/核子下 $^{40,48}$Ca$+^{40,48}$Ca 反应实验数据与 AMD+GEMINI++ 输运模型计算，验证了碰撞参数重建方法的适用性，并揭示了同位旋随碰撞参数减小趋于平衡但未完全平衡的趋势。

费米能区关联源的同位旋组成

Isospin compositions of correlated sources in the Fermi energy domain

该研究通过SMM模型分析FAZIA实验数据，揭示了费米能区周边碰撞中弹核与靶核的同位旋交换接近平衡，并识别出轻碎片的不同来源，其中慢组来自富中子低密度颈部。

费米能附近周边核碰撞中的等标度和与激发能相关的化学分离信号

Isoscaling in Peripheral Nuclear Collisions around the Fermi Energy and a Signal of Chemical Separation from its Excitation Energy Dependence

利用28 Si与124，112 Sn在30和50 MeV/核子的碰撞中观察到的完全重构准粒子的碎片产额数据，研究了等标度效应.观察到等标度参数beta_prime与束流能量无关的激发能依赖性。对于一个给定的准射弹在与不同的目标反应中产生没有isoscale观察。因此，等标度反映了与由初始准抛射体样品代表的不同靶反应中的N/Z平衡水平。激发能对等标度参数β_prime的依赖性，经对1/T温度依赖性的修正后，在4 MeV/核子以上不遵循均匀系统的趋势，从而可能表明开始分离成同位旋非对称稀相和同位旋对称密相.

超允许费米β衰变的同位旋对称性破缺修正的改进计算

An improved calculation of the isospin-symmetry-breaking corrections to superallowed Fermi beta decay

本文报道了对超允许核β衰变的同位旋对称性破缺修正的壳模型计算。最重要的改进是纳入核心轨道，这被证明有一个显着的影响，在径向波函数的母态和子态的不匹配。我们确定哪些核心轨道是重要的，包括从检查测量的光谱因素在单核子拾取反应。我们还研究了新的辐射校正计算Marciano和Sirlin，并通过一个简单的重组，表明它是可能的，以保持传统的分离成一个核独立的内辐射项和核依赖的外部长期。我们列出了20个超允许跃迁的三个理论修正的新值，包括13个研究得很好的情况。使用这些新的校正项，13种情况的校正Ft值在统计学上彼此一致，46 V结果的不确定性消失。这些新的计算导致较低的平均Ft值和较高的Vud值。CKM矩阵的顶行元素的平方和现在与酉性完全一致。

费米能重离子碰撞动力学：挑战与机遇

Dynamics of Heavy-Ion Collisions at Fermi Energies: Challenges and Opportunities

费米能重离子反应的动力学是由非统计核子，轻粒子和核团簇的并发发射修改的耗散机制。实验观测量可用于监测弛豫过程驱动相互作用的核系统向平衡的演变。同位旋自由度提供了有趣的新的基本信息的反应机制和有效的介质核子相互作用。

张量关联对扩展BHF方法中核费米海损耗的影响

Effect of tensor correlations on the depletion of nuclear Fermi sea within the extended BHF approach

在推广的Brueckner-Hartree-Fock方法框架下，采用AV 18两体相互作用和微观三体力，研究了张量关联对对称核物质中核费米海耗尽的影响.计算了各分波通道的贡献，包括同位旋单重态T=0通道、同位旋三重态T=1通道和T=0张量3SD 1通道。T=0的中子-质子关联在引起核费米海的损耗中起主导作用。T=0相关性诱导的耗尽几乎完全源于$^3SD_1$张量通道。的同位旋单重态T=0 3SD 1张量的相关性示出的响应的大部分的耗尽，这相当于超过70%的总耗尽在密度区域考虑。TBF导致在高密度下的耗尽增强，远高于经验饱和密度，并且其效果作为密度的函数而增加。

Constraining the density dependence of the symmetry energy: the isospin transport ratio revisited

The isospin diffusion of the quasi-projectile formed in the $^{64,58}Ni$ on $^{64,58}Ni$ reactions in the Fermi energy domain is investigated in the framework of the Boltzmann-Uehling-Uhlenbeck transport model. The well known isospin transport ratio observable is revisited, with the aim of insuring an optimal comparison between experimental data and theoretical calculations and reducing the present uncertainties in the extraction of empirical equation of state parameters. We show that isospin transport ratios are sensitive to all the low order isovector parameters ($E_{sym}$, $L_{sym}$ and $K_…

Strong Interaction Dynamics and Fermi $β$ decay in the nucleon and the nucleus

Nuclear super-allowed $β$ decay has been used to obtain tight limits on the value of the CKM matrix element $V_{ud}$ that is important for unitarity tests, and therefore important for tests of the standard model. Current requirements on precision are so intense that effects formerly thought too small to matter are now relevant. This article is a brief review of personal efforts to include the effects of strong interactions on Fermi $β$ decay. First I examine the role of isospin violation in the decay of the neutron. The size of the necessary correction depends upon detailed strong-interaction …

介质中NN截面、对称势和碰撞参量对同位旋观测值的影响

The Influence of in-medium NN cross-sections, symmetry potential and impact parameter on the isospin observables

利用改进的量子分子动力学模型ImQMD 05程序，研究了介质中核子-核子碰撞截面、对称势和碰撞参量对中能重离子碰撞中同位旋敏感观测值的影响.当入射速度大于费米速度时，我们发现对称势的密度依赖性对双中子质子比$DR(n/p)$和同位旋输运比$R_i$比介质中核子-核子截面起着更重要的作用，只要后者被限制在一个固定的总NN碰撞率.我们还探讨了$DR(n/p)$和$R_i$作为碰撞参量的函数。由于大量产生中等质量碎片是中能重离子碰撞的一个显著特征，我们研究了由不同碎片组构造的同位旋输运比。我们发现，具有$Z\ge20$的快度碎片的同位旋输运比的值大于由整个快度源构造的快度碎片的同位旋输运比的值。我们相信可以对这种现象进行实验研究。这些可以提供由ImQMD计算预测的碎裂时间尺度的显著测试。

通过重离子反应中的异旋输运探测核对称能量的密度依赖性

Probing the density dependence of nuclear symmetry energy through isospin transport in heavy-ion reactions

本文通过重离子反应中的异旋输运研究，探讨核对称能量的密度依赖性，结合实验数据与传输模型，提取对称能量的约束，为核方程态和致密物质研究提供支持。