在色玻璃凝聚框架下,将Sudakov效应运用到矢量介子产生中,计算了衍射遍举和衍射离解两种过程中轻(φ)和重(J/ψ)介子产生的微分截面和总截面。首先,利用数值方法求解微分积分形式的领头阶偶极子演化方程和Sudakov抑制的次领头阶偶极子...在色玻璃凝聚框架下,将Sudakov效应运用到矢量介子产生中,计算了衍射遍举和衍射离解两种过程中轻(φ)和重(J/ψ)介子产生的微分截面和总截面。首先,利用数值方法求解微分积分形式的领头阶偶极子演化方程和Sudakov抑制的次领头阶偶极子演化方程,得到相应的偶极子散射振幅,研究发现Sudakov抑制的次领头阶偶极子散射振幅小于同一快度下领头阶的偶极子散射振幅,随着快度增加两者之间的差距越来越大,由此表明Sudakov效应压低了偶极子散射振幅的演化速度。其次,将这些偶极子散射振幅应用到衍射矢量介子产生模型中,描述HERA(hadron electron ring accelerator)能区φ和J/ψ介子产生相关实验数据,得到Sudakov抑制时的χ^(2)/N_(p)=1.26远小于领头阶时的χ^(2)/N_(p)=1.87,由此Sudakov效应提高了模型的精度,使得修正后的偶极子散射振幅能较好地描述相关数据,表明了Sudakov效应在矢量介子产生中起着重要的作用。展开更多
The meson productions in Au+Au and/or Pb+Pb collisions at AGS, SPS, RHIC, and LHC energies have been studied systematically with a hadron and string cascade model LUCIAE. After considering the energy dependence of th...The meson productions in Au+Au and/or Pb+Pb collisions at AGS, SPS, RHIC, and LHC energies have been studied systematically with a hadron and string cascade model LUCIAE. After considering the energy dependence of the model parameter α in string fragmentation function and adjusting it to the experimental data of charged multiplicity to a certain extent, the model predictions for meson yield, rapidity, and transverse mass distributions are compatible with the experimental data at AGS, SPS and RHIC energies. A calculation for Pb+Pb collisions at LHC energy is given as well. The obtained fractional variable in string fragmentation function shows a saturation in energy dependence. It is discussed that the saturation of fractional variable in string fragmentation function might be a qualitative representation of the energy dependence of nuclear transparency.展开更多
文摘在色玻璃凝聚框架下,将Sudakov效应运用到矢量介子产生中,计算了衍射遍举和衍射离解两种过程中轻(φ)和重(J/ψ)介子产生的微分截面和总截面。首先,利用数值方法求解微分积分形式的领头阶偶极子演化方程和Sudakov抑制的次领头阶偶极子演化方程,得到相应的偶极子散射振幅,研究发现Sudakov抑制的次领头阶偶极子散射振幅小于同一快度下领头阶的偶极子散射振幅,随着快度增加两者之间的差距越来越大,由此表明Sudakov效应压低了偶极子散射振幅的演化速度。其次,将这些偶极子散射振幅应用到衍射矢量介子产生模型中,描述HERA(hadron electron ring accelerator)能区φ和J/ψ介子产生相关实验数据,得到Sudakov抑制时的χ^(2)/N_(p)=1.26远小于领头阶时的χ^(2)/N_(p)=1.87,由此Sudakov效应提高了模型的精度,使得修正后的偶极子散射振幅能较好地描述相关数据,表明了Sudakov效应在矢量介子产生中起着重要的作用。
基金The project supported by National Natural Science Foundation of China under Grant Nos.19975075,10135030,and 10075035,National Research Council of Thailand (1.CH7/2454)
文摘The meson productions in Au+Au and/or Pb+Pb collisions at AGS, SPS, RHIC, and LHC energies have been studied systematically with a hadron and string cascade model LUCIAE. After considering the energy dependence of the model parameter α in string fragmentation function and adjusting it to the experimental data of charged multiplicity to a certain extent, the model predictions for meson yield, rapidity, and transverse mass distributions are compatible with the experimental data at AGS, SPS and RHIC energies. A calculation for Pb+Pb collisions at LHC energy is given as well. The obtained fractional variable in string fragmentation function shows a saturation in energy dependence. It is discussed that the saturation of fractional variable in string fragmentation function might be a qualitative representation of the energy dependence of nuclear transparency.
