Systematic approach to thermal leptogenesis

Abstract

In this work we study the contribution to leptogenesis from ∆L = 1 decay and scattering processes mediated by the Higgs with quarks in the initial and final states using the formalism of non-equilibrium quantum field theory. Starting from fundamental equations for correlators of the quantum fields we derive quantum-corrected Boltzmann and rate equations for the total lepton asymmetry improved in that they include quantum-statistical effects and medium corrections to the quasiparticle properties. To compute the collision term we take into account one-and two-loop contributions to the lepton self-energy and use the extended quasiparticle approximation for the Higgs two-point function. The resulting CP-violating and washout reaction densities are numerically compared to the conventional ones.

NonthermalCPviolation in soft leptogenesis

“…[49] which gives the dependence on the distribution functions 1+η i f eq i +η j f eq j in agreement with the results derived from nonequilibrium quantum field theory [48,[50][51][52][53][54][55][56][57][58][59][60][61][62] in contrast to the results of Refs. [31,63] …”

Systematic approach toΔL=1processes in thermal leptogenesis

“…In this section we briefly review results obtained in [22] and introduce notation that will be used in the rest of the paper. As has been argued in [22], the equation of motion for the lepton asymmetry can be derived by considering the divergence of the lepton current. In the FRW Universe j µ L = (n L , 0) and therefore it is related to the total lepton abundance by:…”

“…The first category includes ∆L = 2 scattering processes mediated by the Majorana neutrinos. A first-principle analysis of such processes free of the notorious doublecounting problem has been presented in [22]. The second category includes ∆L = 1 decay and scattering processes mediated by the Higgs.…”

Improving electro-weak fits with TeV-scale sterile neutrinos

“…According to this scenario the lepton asymmetry which is produced by the heavy neutrinos * evgeny.akhmedov@mpi-hd.mpg.de † alexander.kartavtsev@mpp.mpg.de ‡ manfred.lindner@mpi-hd.mpg.de § lisa.michaels@mpi-hd.mpg.de ¶ juri.smirnov@mpi-hd.mpg.de is converted into the baryon asymmetry by anomalous electro-weak processes [8][9][10]. Depending on the values of the masses and couplings in (1) the generation of the asymmetry proceeds either through decays [11][12][13][14][15][16][17][18][19][20][21][22][23] or via oscillations of the heavy neutrinos [24]. The extension of the SM spectrum by sterile neutrino states may even provide a solution to the third problem, since sterile neutrinos are a perfect dark matter candidate (see e.g.…”