Non-equilibrium corrections to the energy spectra of massive particles in the expanding universe

被引:7
作者
Dolgov, AD [1 ]
机构
[1] ITEP,MOSCOW 113259,RUSSIA
关键词
D O I
10.1016/S0550-3213(97)00189-2
中图分类号
O412 [相对论、场论]; O572.2 [粒子物理学];
学科分类号
摘要
Deviations from kinetic equilibrium of massive particles caused by the universe expansion are calculated analytically in the Boltzmann approximation. For the case of an energy-independent amplitude of elastic scattering, an exact partial differential equation is derived instead of the usual integro-differential equation. A simple perturbative solution of the former is found. For the case of an energy-dependent amplitude the problem cannot be reduced to a differential equation but the solution of the original integro-differential equation can be found in terms of a Taylor expansion, which in the case of a constant amplitude shows perfect agreement with the perturbative solution of the differential equation. Corrections to the spectrum of (possibly) massive tau-neutrinos are calculated. The method may be of more general interest and can be applied to the calculation of spectrum distortion in other (not necessarily cosmological) non-equilibrium processes. (C) 1997 Elsevier Science B.V.
引用
收藏
页码:437 / 447
页数:11
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