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INVESTIGATION OF EARY UNIVERSE BASED ON UNIFIED THEORIES

基于统一理论的太初宇宙研究

基本信息

批准号：
08640341
负责人：
YOSHIMURA Motohiko
金额：
$ 1.15万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

In most previous study of physical cosrnology effect of cosmic environment has been evaluated by using the Boltzmann equation suitably averaged in thermal medium. This approach is based on the on-shell S-matrix element, tire transition matrix element between the infinite past and the h6 : rite future, 'and neglects subtle quantum mechanical correlation at 6nite intermediate times of the on-going process. In the present investigation a fully quantum mechanical approach is adopted, using the in influence functional method. In particular, pair annihilation of heavy stable particle that occurs in the early universe was investigated, and quantum kinetic equation for the momentum distribution of the annihilating particle has been derived.A crossing symmetric Hartree approximation that determines self-consistently the equilibrium distribution is developed, and its Markovian approximation is shown to generalize the Boltzmann equation, including off-shell effects. The off-shell effect is dominant at low temperatures. The deck changes the equilibrium distribution from the familiar 1/(e^<omegamu/gamma>-1) modified one given by a Gibbs formula. Integrated over momenta, tire particle number density becomes roughly of order (coupling) * ROO<T/M>・T^3 at low 'temperatures for the S-wave annihilation. The relic mass density in the present universe is insensitive the coupling strength in a large range of the mass and the coupling parameters, and scales with the VAMP mass as <approximately equal> 6*10^4eVcm^<-3>(M/geV)^<4/3>

在以往的物理宇宙学研究中，宇宙环境效应的计算大多是用在热介质中适当平均的玻尔兹曼方程来进行的。这种方法是基于在壳S-矩阵元，即无限过去和无限未来之间的过渡矩阵元，而忽略了在进行中的过程的6 nite中间时刻的微妙的量子力学关联。在本研究中，采用了完全量子力学的方法，使用的影响功能的方法。研究了早期宇宙中重稳定粒子对的湮灭，导出了湮灭粒子动量分布的量子动力学方程，发展了自洽确定平衡态分布的交叉对称Hartree近似，并证明了其Markovian近似推广了Boltzmann方程，包括离壳效应.在低温下，脱壳效应占主导地位。甲板改变了平衡分布，从熟悉的1/（e^<omegamu/gamma>-1）修改一个吉布斯公式。对动量积分，在低温下S波湮灭的粒子数密度近似为（耦合）* RO 0 <T/M>·T^3。在很大的质量和耦合参数范围内，现今宇宙的残余质量密度对耦合强度不敏感，与VAMP质量成<approximately equal>6*10^4eVcm^<-3>（M/geV）^<4/3>的比例关系