AI 中文总结
该研究采用耦合轻集团形成动力学方法的输运模型，探究FOPI能区重离子碰撞中轻集团自由度对集体流的影响，明确了不同束流能量下该效应的变化规律及核子数标度特性。
AI 中文摘要
在耦合了轻集团形成动力学方法的格点玻尔兹曼-乌伦贝克-乌伦贝克输运模型框架下，我们采用依赖密度、动量和同位旋的N5LO Skyrme赝势，研究了FOPI能区（束流能量E_beam=120~1500 A MeV）Au+Au碰撞中显式轻集团自由度对集体流的影响。我们首先通过将计算得到的轻集团产额与中心Au+Au碰撞的FOPI数据对比，对该动力学方法进行基准检验；随后分析了半中心碰撞中质子和轻核（氘核、氚核、³He、⁴He）的集体流。针对质子，我们对比了考虑和不考虑动力学轻集团自由度的计算结果，以量化动力学集团形成对质子定向流（v₁）、椭圆流（v₂）、三角流（v₃）和四角流（v₄）的影响。我们发现，在E_beam=120~150 A MeV时，动力学轻集团效应会显著改变质子的v₁~v₄流；在E_beam=250~400 A MeV时，该效应仍可见；在E_beam≳600 A MeV时，效应逐渐减弱。针对轻核，该动力学方法能再现FOPI流数据的整体束流能量依赖关系，在E_beam≥400 A MeV时符合度更佳。我们进一步检验了模型计算和实验数据中v₂/A的核子数标度，发现动力学轻集团形成方法定性再现了观测到的标度行为。这些结果表明，在约600 A MeV以下的重离子碰撞中，动力学处理轻集团形成对解释集体流至关重要，尽管在更高碰撞能量下，集团效应对质子流的影响较小。
英文摘要
Within a lattice Boltzmann-Uehling-Uhlenbeck transport model coupled to a kinetic approach for light-cluster formation, we investigate the impact of explicit light-cluster degrees of freedom on collective flows in Au+Au collisions at FOPI energies with beam energies $E_{\rm beam}$= $120$--$1500 A$ MeV by using a density-, momentum-, and isospin-dependent N$5$LO Skyrme pseudopotential. We first benchmark the kinetic approach by comparing the calculated light-cluster yields with FOPI data in central Au+Au collisions. We then analyze the collective flows of protons and light nuclei (deuterons, tritons, $^{3}\mathrm{He}$, and $^{4}\mathrm{He}$) in mid-central collisions. For protons, calculations with and without dynamical light-cluster degrees of freedom are compared to quantify the influence of dynamical cluster formation on proton directed ($v_1$), elliptic ($v_2$), triangular ($v_3$), and quadrangular ($v_4$) flows. We find that the dynamical light-cluster effect appreciably modifies proton $v_1$--$v_4$ flows at $E_{\rm beam}=120$--$150 A$ MeV, remains visible at $E_{\rm beam}=250$--$400 A$ MeV, and gradually weakens at $E_{\rm beam}\gtrsim 600 A$ MeV. For light nuclei, the kinetic approach captures the overall beam-energy dependence of the FOPI flow data, with better agreement for $E_{\rm beam}\geq 400 A$ MeV. We further examine the nucleon-number scaling of $v_2/A$ in both model calculations and experimental data, finding that the kinetic light-cluster formation approach qualitatively reproduces the observed scaling behavior. These results highlight the importance of a dynamical treatment of light-cluster formation for interpreting collective flows in heavy-ion collisions below about $600 A$ MeV, although the clustering effects on proton flows are minor at higher collision energies.
Comments20 pages, 15 figures, 1 table
