Decay of a Yukawa fermion at finite temperature and applications to leptogenesis

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.

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“…(49), so that the integration can be extended to the whole uv plane. Using their definitions and Eq.…”

Section: B Equilibrium Solution For Majorana Propagatormentioning

confidence: 99%

Systematic approach to thermal leptogenesis

et al. 2013

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“…These include for example ∆L = 2 washout [4,8], ∆L = 1 scatterings [5], momentum dependence [21], thermal corrections [8,22], flavour coupling from the Higgs and quark asymmetries [6,23,10,24,18], quantum kinetic effects [25].…”

Section: Kinetic Equations For the N 1 Dominated Scenariomentioning

confidence: 99%

Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations

Blanchet

Bari

Jones

et al. 2013

J. Cosmol. Astropart. Phys.

122

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Leptogenesis with heavy neutrino flavours is discussed within a density matrix formalism. We write the density matrix equation, describing the generation of the matter-antimatter asymmetry, for an arbitrary choice of the right-handed (RH) neutrino masses. For hierarchical RH neutrino masses lying in the fully flavoured regimes, this reduces to multiple-stage Boltzmann equations. In this case we recover and extend results previously derived within a quantum state collapse description. We confirm the generic existence of phantom terms. However, taking into account the effect of gauge interactions, we show that they are washed out at the production with a wash-out rate that is halved compared to that one acting on the total asymmetry. In the N 1 -dominated scenario they cancel without contributing to the final baryon asymmetry. In other scenarios they do not in general and they have to be taken into account. We also confirm that there is a (orthogonal) component in the asymmetry produced by the heavier RH neutrinos which completely escapes the washout from the lighter RH neutrinos and show that phantom terms additionally contribute to it. The other (parallel) component is washed out with the usual exponential factor, even for weak washout. Finally, as an illustration, we study the two RH neutrino model in the light of the above findings, showing that phantom terms can contribute to the final asymmetry also in this case.

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“…Accordingly, the initial or previously generated asymmetry is almost entirely washed out and only the N 1 contribution survives. Possible corrections to our analysis (which we will neglect) include ΔL ¼ 1 scatterings [58,59], thermal corrections [17,60], flavor effects [61,62] and quantum kinetic effects [63,64]. A more comprehensive analysis taking into account some or even all of these effects is left for future work.…”

Section: Ingredients For Leptogenesismentioning

confidence: 99%

Low-scale leptogenesis in the scotogenic neutrino mass model

2018

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The scotogenic model proposed by Ernest Ma represents an attractive and minimal example for the generation of small Standard Model neutrino masses via radiative corrections in the dark matter sector. In this paper, we demonstrate that, in addition to neutrino masses and dark matter, the scotogenic model also allows to explain the baryon asymmetry of the Universe via low-scale leptogenesis. First, we consider the case of two right-handed neutrinos (RHNs) N 1;2 , for which we provide an analytical argument why it is impossible to push the RHN mass scale below M min 1 ∼ 10 10 GeV, which is identical to the value in standard thermal leptogenesis in the type-I seesaw scenario with the same washout strength. Then, we present a detailed study of the three-RHN case based on both an analytical and a numerical analysis. In the case of three RHNs, we obtain a lower bound on the N 1 mass of around 10 TeV. Remarkably enough, successful low-scale leptogenesis can be achieved without any degeneracy in the RHN mass spectrum. The only necessary condition is a suppression in the N 1 Yukawa couplings, which results in suppressed washout and a small active neutrino mass of around 10 −12 eV. This leads to the fascinating realization that low-scale leptogenesis in the scotogenic model can be tested in experiments that aim at measuring the absolute neutrino mass scale.

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Decay of a Yukawa fermion at finite temperature and applications to leptogenesis

Cited by 44 publications

References 46 publications

Systematic approach to thermal leptogenesis

Systematic approach to thermal leptogenesis

Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations

Low-scale leptogenesis in the scotogenic neutrino mass model

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