Thermal particle production in the early universe [Elektronische Ressource] / submitted by: Denis Besak

Thermal particle production in theearly UniverseDissertationSubmitted by:Denis BesakFakulta¨t fu¨r Physik,Universit¨at BielefeldJune 2010Referees: Prof.Dr.Dietrich B¨odekerProf.Dr.Mikko LaineContentsPublished work from thesis 51. Introduction 62. Quantum field theory in a hot thermal bath 92.1. Perturbation theory at finite temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.1. A short review of the imaginary-time formalism . . . . . . . . . . . . . . . . . . . . . . 92.1.2. Scales and effective theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.2. Hard Thermal Loops (HTL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.3. Perturbation theory close to the lightcone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.3.1. Thermal width and asymptotic mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.3.2. A new class of diagrams: Collinear Thermal Loops (CTL) . . . . . . . . . . . . . . . . 202.3.3. A general power-counting for CTLs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212.3.4. The CTL self-energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233. Thermal particle production and the LPM effect 263.1. Thermal particle production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.1.1. Particle production rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .