Equation of state with quantum statistics corrections is derived for a multi-component gas of particles interacting through the repulsive and attractive van der Waals (vdW) forces up to first few orders over a small parameter $δ\approx \hbar^3 n(mT)^{-3/2}[g(1- bn)]^{-1}$, where $n$ and $T$ are the particle number density and temperature, $m$ and $g$ the particle mass and degeneracy factor. The parameter $b$ corresponds to the vdW excluded volume. For interacting system of Fermi nucleon and Bose $α$ particles, a small impurity of $α$ particles to the nucleon system at leading first order in both $α$ particle and nucleon small parameters $δ$ does not change much the basic results for the symmetric nuclear matter. The particle number fluctuations $ω$ determined by the isothermal in-compressibility $\mathcal{K}(n,T)$ can be obtained analytically at the same first order quantum-statistics approximation for symmetric nucleon matter. Our approximate analytical results appear to be in good agreement with the accurate numerical calculations.
We derive the values of nuclear symmetry energy, its components, as well as pressure in finite nuclei at saturation density from their corresponding values in nuclear matter obtained in non-relativistic Brueckner-Hartree-Fock calculations with the realistic Bonn B and Bonn CD potentials using the coherent density fluctuation model in the framework of a self-consistent Skyrme-Hartree-Fock plus BCS method. We focus on three isotopic chains of spherical nuclei (Ni, Sn, and Pb) and compare our results with those obtained with an effective Brueckner density-dependent potential. The role of the thre…
The multiplicity fluctuations are studied in the van der Waals excluded volume hadron-resonance gas model. The calculations are done in the grand canonical ensemble within the Boltzmann statistics approximation. The scaled variances for positive, negative and all charged hadrons are calculated along the chemical freeze-out line of nucleus-nucleus collisions at different collision energies. The multiplicity fluctuations are found to be suppressed in the van der Waals gas. The numerical calculations are presented for two values of hard-core hadron radius, $r=0.3$ fm and 0.5 fm, as well as for th…
Anomalous Behavior of Giant Monopole Resonance Energy with Nuclear Matter Incompressibility in the framework of Relativistic Mean Field Formalism and Coherent Density Fluctuation Model
Institute of Physics, Sachivalaya Marg（萨奇瓦拉亚Marg物理研究所）
The equation of state with quantum statistics corrections is used for particle number fluctuations $ω$ of isotopically symmetric nuclear matter with interparticle van der Waals and Skyrme local density interactions. The fluctuations, $ω\propto 1/\mathcal{K}$, are analytically derived through the isothermal incompressibility $\mathcal{K}$ at first order over a small quantum-statistics parameter. Our approximate analytical results appear to be in good agreement with the results of accurate numerical calculations. These results are also close to those obtained by using more accurate Tolman and Ro…
Two-particle correlations are a widely used tool for studying relativistic nuclear collisions. Multiplicity fluctuations comparing charge and particle species have been studied as a possible signal for Quark-Gluon Plasma (QGP) and the QCD critical point. These fluctuation studies all make use of particle variances which can be shown to originate with a two-particle correlation function. Momentum correlations and covariances of momentum fluctuations, which arise from the same correlation function, have also been used to extract properties of the nuclear collision medium such as the shear viscos…
Evidence for Color Fluctuations in Hadrons from Coherent Nuclear Diffraction}
利用基于量子色动力学的弹丸尺寸涨落处理方法计算了相干强子-核过程的非弹性衍射截面$σ_{diff}$。我们发现，平均尺寸附近的波动给出了主要的贡献与$ \le few \%$贡献的小尺寸配置的截面。$σ_{diff}$的计算值与有限的可用数据一致。强调了在高能费米实验室固定靶实验中对大范围射弹进行相干衍射研究的重要性。这些显着的颜色起伏的相对论性重离子碰撞的影响进行了讨论。
A new alternative approach to calculate the ratio of the surface to volume components of the nuclear symmetry energy is proposed in the framework of the coherent density fluctuation model (CDFM). A new expression (scheme II) for the ratio is derived consistently within the model. This expression appears in a form more direct and physically motivated than the expression (scheme I) that was used in our previous works within the CDFM and avoids preliminary assumptions and mathematical ambiguities in scheme I. The calculations are based on the Skyrme and Brueckner energy-density functionals for nu…
The time evolution of particle number fluctuations in nuclear collisions at intermediate energies ($E_{\rm lab} = 1.23-10A$ GeV) is studied by means of the UrQMD-3.5 transport model. The transport description incorporates baryonic interactions through a density-dependent potential. This allows for an implementation of a first order phase transition including a mechanically unstable region at large baryon density. The scaled variance of the baryon and proton number distributions is calculated in the central cubic spatial volume of the collisions at different times. A significant enhancement of …
We study the influence of global baryon number conservation on the non-critical baseline of net baryon cumulants in heavy-ion collisions in a given acceptance, accounting for the asymmetry between the mean-numbers of baryons and antibaryons. We derive the probability distribution of net baryon number in a restricted phase space from the canonical partition function that incorporates exact conservation of baryon number in the full system. Furthermore, we provide tools to compute cumulants of any order from the generating function of uncorrelated baryons constrained by exact baryon number conser…
Fluctuation Probes of Early-Time Correlations in Nuclear Collisions
相关性测量意味着，各向异性流在核碰撞包括一个新的三角形组件以及更熟悉的椭圆流的贡献。三角形流已被归因于碰撞体积的初始形状中的逐事件波动。我们提出两个问题：1）这些形状波动如何影响其他逐个事件的可观测量？2)我们能否将早期波动的基本信息从所产生的复杂流动中分离出来？我们研究相关性和波动观测的框架中，通量管在一个早期的磁共振阶段后产生流体动力学流。计算的多重数和横向动量涨落与62.4 GeV Au+Au到2.76 TeV Pb+Pb的数据非常吻合。
