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Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca+Ca by Quantum Molecular Dynamics Model 下载免费PDF全文
Anisotropic flows (v1, v2, v3 and v4) of light fragments up to the mass number 4 as a function of rapidity are studied for 25 MeV/nucleon ^40Ca + ^40Ca at large impact parameters by a quantum molecular dynamics model. A phenomenological scaling behaviour of rapidity dependent flow parameters vn (n = 1, 2, 3 and 4) is found as a function of mass number plus a constant term, which may arise from the interplay of collective and random motions. In addition, v4/v2^2 keeps to be almost independent of rapidity and remains a rough constant of 1/2 for all light fragments. 相似文献
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We investigate the cross sections of the elastic electron or positron scat tering from 208 Pb, ^12C ^12,16O and ^28,32S by the relativistic partial-wave expansion method using the static charge density distribution from the self-consistent relativistic mean fiel model and also calculate the charge form factor for ^12'16O and ^28,32S. The numerical results are compared with the available data. Calculations indicate that the extended charge density distributions of ^12O and ^28S have observable effects on the cross sections of the electron or positron scattering as well as the charge form factors. 相似文献
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Scaling of anisotropic flows and nuclear equation of state in intermediate energy heavy ion collisions 下载免费PDF全文
Elliptic flow ($v_2$) and hexadecupole flow ($v_4$) of light
clusters have been studied in detail for 25 MeV/nucleon $^{86}$Kr
+ $^{124}$Sn at large impact parameters by using a quantum
molecular dynamics model with different potential parameters. Four
sets of parameters including soft or hard equation of state (EOS)
with or without symmetry energy term are used. Both
number-of-nucleon ($A$) scaling of the elliptic flow versus
transverse momentum ($p_{\rm t}$) and the scaling of $v_4/A^{2}$ versus
$(p_{\rm t}/A)^2$ have been demonstrated for the light clusters in all
above calculation conditions. It is also found that the ratio of
$v_4/{v_2}^2$ maintains a constant of 1/2 which is independent of
$p_{\rm t}$ for all the light fragments. Comparisons among different
combinations of the EOS and the symmetry potential term show that
the above scaling behaviours are sound and independent of the
details of potential, while the strengths of flows are sensitive
to the EOS and the symmetry potential term. 相似文献
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方德清 郭威 马春旺 王鲲 颜廷志 马余刚 蔡翔舟 沈文庆 任中洲 孙志宇 M. Hosoi T. Izumikawa R. Kanungo S. Nakajima T. Ohnishi T. Ohtsubo A. Ozawa T. Suda K. Sugawara T. Suzuki A. Takisawa K. Tanaka T. Yamaguchi I. Tanihata 《中国物理 C》2008,32(Z2):34-37
The longitudinal momentum distribution (P//) of fragments after one-proton removal from 23Al and reaction cross sections (σR) for 23,24Al on carbon target at 74A MeV have been measured simultaneously. An enhancement in σR is observed for 23Al compared with 24Al. The full width at half maximum of the P// distribution for 22Mg fragments has been determined to be 232±28 MeV/c. Analysis of P// using the Few-Body Glauber Model indicates a dominant d-wave configuration for the valence proton in the ground state of 23Al. The exotic structure in 23Al is discussed. 相似文献
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The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model.The nucleonnumber scaling of elliptic flow exists and the scaling of the ratios of v4/v22and v3/(v1v2)is applicable to collisions at almost all impact parameters except for peripheral collisions. 相似文献
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Anisotropic flows per nucleon (v1/A, v2/A, v3/A and v4/A) of light fragments up to the mass number 4 as a function of transverse momentum per nucleon are studied for 55 Me V/nucleon 58Fe+58Fe and 58 Ni+ 58 Ni at large impact parameters by the isospin-dependent quantum molecular dynamics model. The effects of symmetry energy and nucleon-nucleon cross sections, which are both isospin-dependent on anisotropic flows, are studied in detail. In comparison of the two systems with or without symmetry potential term, the results show that the strength of flows is sensitive to symmetry potential and nucleon-nucleon cross sections, which mainly cause a repulsion effect in this energy region. 相似文献
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