Nucleon effective mass splitting and density-dependent symmetry energy effects on elliptic flow in heavy ion collisions at E_(lab)= 0.09 ~ 1.5 GeV/nucleon |
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摘 要: | By incorporating an iso spin-dependent form of the momentum-dependent potential in the ultra-relativistic quantum molecular dynamics(UrQMD) model,we systematically investigate effects of the neutron-proton effective mass splitting m*_(n-p)=m*_n-m*_p/m and the density-dependent nuclear symmetry energy E_(sym)(ρ) on the elliptic flow v_2 in~(197)Au+~(197) Au collisions at beam energies from 0.09 to 1.5 GeV/nucleon.It is found that at higher beam energies(≥0.25 GeV/nucleon) with the approximately 75 MeV difference in slopes of the two different E_(sym)(ρ),and the variation of m*_(n-p) ranging from-0.03 to 0.03 at saturation density with isospin asymmetry δ=(ρ_n-ρ_p)/ρ-0.2,the E_(sym)(ρ) has a stronger influence on the difference in v_2 between neutrons and protons,i.e.,v_2~n-v_2~p,than m*_(n-p) has.Meanwhile,at lower beam energies(≤0.25 GeV/nucleon),v_2~n-v_2~p is sensitive to both the E_(sym)(ρ) and the m*_(n-p).Moreover,the influence of m*_(n-p) on v_2~n-v_2~p is more evident with the parameters of this study when using the soft,rather than stiff,symmetry energy.
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收稿时间: | 2020-07-01 |
Nucleon effective mass splitting and density-dependent symmetry energy effects on elliptic flow in heavy ion collisions at Elab= 0.09 ~ 1.5 GeV/nucleon |
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Authors: | Luyao Tong Pengcheng Li Fupeng Li Yongjia Wang Qingfeng Li Fanxin Liu |
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Institution: | 1. Department of Physics, Zhejiang University of Technology, Hangzhou 310023, China2. School of Science, Huzhou University, Huzhou 313000, China3. School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China4. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China |
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Abstract: | By incorporating an isospin-dependent form of the momentum-dependent potential in the ultra-relativistic quantum molecular dynamics (UrQMD) model, we systematically investigate effects of the neutron-proton effective mass splitting \begin{document}$m_{n-p}^{*}$\end{document}![]() =\begin{document}$\frac{m_{n}^{*}-m_{p}^{*}}{m}$\end{document}![]() and the density-dependent nuclear symmetry energy \begin{document}$E_{\rm{sym}}(\rho)$\end{document}![]() on the elliptic flow \begin{document}$v_2$\end{document}![]() in \begin{document}$^{197}{{\rm{Au}}}$\end{document}![]() + \begin{document}$^{197}{{\rm{Au}}}$\end{document}![]() collisions at beam energies from 0.09 to 1.5 GeV/nucleon. It is found that at higher beam energies (\begin{document}$\geqslant$\end{document}![]() 0.25 GeV\begin{document}$/$\end{document}![]() nucleon) with the approximately 75 MeV difference in slopes of the two different \begin{document}$E_{\rm{sym}}(\rho)$\end{document}![]() , and the variation of \begin{document}$m_{n-p}^{*}$\end{document}![]() ranging from –0.03 to 0.03 at saturation density with isospin asymmetry \begin{document}$\delta=(\rho_{n}-\rho_{p})/\rho=0.2$\end{document}![]() , the \begin{document}$E_{\rm{sym}}(\rho)$\end{document}![]() has a stronger influence on the difference in \begin{document}$v_{2}$\end{document}![]() between neutrons and protons, i.e., \begin{document}$v_{2}^{n}-v_{2}^{p}$\end{document}![]() , than \begin{document}$m_{n-p}^{*}$\end{document}![]() has. Meanwhile, at lower beam energies (\begin{document}$\leqslant$\end{document}![]() 0.25 GeV\begin{document}$/$\end{document}![]() nucleon), \begin{document}$v_{2}^{n}-v_{2}^{p}$\end{document}![]() is sensitive to both the \begin{document}$E_{\rm{sym}}(\rho)$\end{document}![]() and the \begin{document}$m_{n-p}^{*}$\end{document}![]() . Moreover, the influence of \begin{document}$m_{n-p}^{*}$\end{document}![]() on \begin{document}$v_{2}^{n}-v_{2}^{p}$\end{document}![]() is more evident with the parameters of this study when using the soft, rather than stiff, symmetry energy. |
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Keywords: | nuclear symmetry energy heavy ion collision elliptic flow |
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