Protecting the baryon asymmetry with thermal masses

Davidson, Sacha; Kainulainen, Kimmo; Olive, Keith A.

doi:10.1016/0370-2693(94)90361-1

Cited by 24 publications

(30 citation statements)

References 21 publications

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“…Dreiner and Ross [8] have shown that, for a second or weakly first order EWPT, inclusion of the particle masses while analyzing the chemical equilibrium equations for T < T EW gives B ∼ 10 −7 ∆L for (B − L) initial = 0, where ∆L is the initial lepton generations' asymmetry ∆L = i>j (L i − L j ) and it is expected to be of the same order of magnitude as the initial lepton number. While Davidson et al [9] show that the inclusion of thermal mass effects for T > ∼ T EW also gives B ∼ 10 −7 ∆L at T ∼ T EW . Thus, irrespective of the order (first, second or weakly first) of EWPT a non-zero, though severly diluted, value of B should survive today if initially, at T >> T EW , B − L had been zero.…”

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confidence: 97%

GUT's have the guts to defy sphalerons

Mohan

1996

Physics Letters B

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We show that the baryon asymmetry produced by the out of equilibrium decay of heavy GUT scalars can be the baryon asymmetry that is observed today. No restrictions need be imposed on the initial values of B, L and B − L, nor on the neutrino masses; no new symmetries need be gauged nor new fermions introduced. We find two mechanisms that can bring this about for any GUT gauge group. Two illustrative models are discussed that are robust, and need just two (at most four) more GUT scalar fields than the minimal model. The additional scalar fields can also help in generating an adequately large value of the CP violation parameter and in efficiently annihilating the monopoles. Our work should firmly re-establish heavy GUT scalars as probable progenitors of today's baryon asymmetry.

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mentioning

confidence: 97%

GUT's have the guts to defy sphalerons

Mohan

1996

Physics Letters B

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“…above the phase transition x f = m f (T )/T [15]. It appears natural to expect that these perturbations should bring about nonzero final asymmetries roughly of the order of perturbations.…”

Section: Finite Mass Effectsmentioning

confidence: 99%

“…If the electroweak phase transition is of second order, then the relevant equilibrium is the one at the broken phase right after the phase transition. Nevertheless, even then a final baryon asymmetry of the same order as in (11) results due from the vacuum mass effects [14,15].…”

Section: Finite Mass Effectsmentioning

confidence: 99%

“…This indeed turns out to be the case with three important refinemets: (i) corrections in the quark sector alone are not sufficient because all the quarks have equal chemical potentials, (ii) one must have unequal corrections between lepton families, so that only Yukawa couplings contribute and (iii) one must have nonzero differences between the leptonic asymmetries (these differences are conserved). Then, if the phase transition is 1st order, the contribution from T > T * equilibrium values get frozen to the universe implying [15] B f ≃ 3 × 10 −7 (∆L eτ + ∆L µτ ),…”

Section: Finite Mass Effectsmentioning

confidence: 99%

“…However, even then a fraction of the primordial baryon number is restored due to the finite mass effects. Depending on the order of the phase transition this would be due to vacuum mass effects [14] or due to the thermal mass corrections [15,16].…”

Section: Introductionmentioning

confidence: 99%

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Primordial baryon asymmetry and sphalerons

Kainulainen¹

1995

Nuclear Physics B - Proceedings Supplements

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I show that a cosmological baryon asymmetry generated at the GUT scale is in general safe against washout due to sphalerons and generic B-or L-violating effects. This result is mainly due to the (almost) conserved number of right-handed electrons at high temperatures T > ∼ O(10) TeV, but also the mass corrections, in particular the thermal masses of leptons act as the protector of the primordial baryon asymmetry.

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Leptogenesis in a Prompt Decay Scenario

Bento

2004

Beyond the Desert 2003

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Abstract. Leptogenesis is studied within the seesaw neutrino mass model in a regime where all sterile neutrinos have prompt rather than delayed decays. It is shown that during neutrino thermal production lepton asymmetries are generated in both active lepton and sterile neutrino sectors. The large B − L asymmetry is slowly pumped into the chemically decoupled right-handed quarks and leptons and baryon number sector which later protect B − L from fast L violating processes. The dependence of the final baryon asymmetry on couplings and masses is totally different from the decay scenario. B does not vanish in the limit of degenerate light neutrinos and the observed asymmetry is naturally obtained for a sum of square masses,m 2 , between the atmospheric neutrino mass gap and 0.2 eV 2 .

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Protecting the baryon asymmetry with thermal masses

Cited by 24 publications

References 21 publications

GUT's have the guts to defy sphalerons

GUT's have the guts to defy sphalerons

Primordial baryon asymmetry and sphalerons

Leptogenesis in a Prompt Decay Scenario

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