Barygenesis without grand unification

Fukugita, M.; Yanagida, Tsutomu T.

doi:10.1016/0370-2693(86)91126-3

Cited by 4,103 publications

(5,600 citation statements)

References 14 publications

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“…With the discovery of neutrino masses in neutrino mixing experiments, leptogenesis [1] has become one of the most attractive explanations of the matter-antimatter asymmetry of the Universe. Indeed, leptogenesis is the direct cosmological consequence of the see-saw mechanism [2], the most elegant way to understand neutrino masses and their lightness compared to all other known massive fermions.…”

Section: Introductionmentioning

confidence: 99%

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

Blanchet¹,

Bari²

2006

J. Cosmol. Astropart. Phys.

121

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We calculate the baryon asymmetry of the Universe in thermal leptogenesis beyond the usual lightest right-handed (RH) neutrino dominated scenario (N 1 DS) and in particular beyond the hierarchical limit (HL), M 1 ≪ M 2 ≪ M 3 , for the RH neutrino mass spectrum. After providing some orientation among the large variety of models, we first revisit the central role of the N 1 DS, with new insights on the dynamics of the asymmetry generation and then discuss the main routes departing from it, focusing on models beyond the HL. We study in detail two examples of 'strong-strong' washout scenarios: one with 'maximal phase' and the limit of very large M 3 , studying the effects arising when δ 2 ≡ (M 2 − M 1 )/M 1 is small. We extend analytical methods already applied to the N 1 DS showing, for example, that, in the degenerate limit (DL), the efficiency factors of the RH neutrinos become equal with the single decay parameter replaced by the sum. Both cases disprove the misconception that close RH neutrino masses necessarily lead to a final asymmetry enhancement and to a relaxation of the lower bounds on M 1 and on the initial temperature of the radiationdominated expansion. We also explain why leptogenesis tends to favor normal hierarchy compared to inverted hierarchy for the left-handed neutrino masses.

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Section: Introductionmentioning

confidence: 99%

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

Blanchet¹,

Bari²

2006

J. Cosmol. Astropart. Phys.

121

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“…6 Finally we discuss the evolution of u after this period to see the relation of this scenario to the µ-term. We assume H I ∼ 10 13 GeV during the inflation on the basis of the CMB data and T R < ∼ 10 9 GeV.…”

Section: Asymmetrymentioning

confidence: 97%

“…The particle-antiparticle number asymmetry δn f can be approximately related to the corresponding chemical potential µ f . In the case of µ f ≪ T , 6 ThisT R is the marginal value for the cosmological gravitino problem [23]. 7 Such a u 0 may be expected to be determined either by the nonrenormalizable terms or by the pure radiative symmetry breaking effect in which u 0 is estimated by using the renormalization group equation as discussed in [25].…”

Section: Generation Of B Asymmetrymentioning

confidence: 99%

μ-term as the origin of baryon and lepton number asymmetry

Suematsu¹

2005

J. Phys. G: Nucl. Part. Phys.

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We study a possibility of combining an origin of the µ-term and the baryon and lepton number asymmetry. If we assume that the µ-term is generated through a flat direction of a singlet scalar field, the coherent oscillation of this condensate around its potential minimum can store the global U(1) charge asymmetry. The decay of this condensate can distribute this asymmetry into the lepton and baryon number asymmetry as far as its decay occurs at an appropriate temperature. We examine the compatibility between this scenario and the small neutrino mass generation based on both the ordinary seesaw mechanism and the bilinear R-parity violating terms. *

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“…1 Although, there still does not exist an agreed-upon microscopic theory of inflation, there has been a lot of progress in this direction in recent years. The theory of the primordial synthesis of nuclei -BBN, which starts at a temperature of about an MeV, is also quite successful in explaining observations.…”

Section: Jhep05(2009)083mentioning

confidence: 99%

Neutrino masses, Baryon asymmetry, dark matter and the moduli problem — A complete framework

Kumar¹

2009

J. High Energy Phys.

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Neutrino masses, Baryon asymmetry, dark matter and the moduli problem -A complete framework E-mail: kpiyush@berkeley.eduAbstract: Recent developments in string theory have led to "realistic" string compactifications which lead to moduli stabilization while generating a hierarchy between the Electroweak and Planck scales at the same time. However, this seems to suggest a rethink of our standard notions of cosmological evolution after the end of inflation and before the beginning of BBN. This epoch is crucial for addressing the issues of neutrino masses, baryon asymmetry, Dark Matter (DM) abundance and the moduli (gravitino) problem. We argue that within classes of realistic string compactifications as defined above, there generically exists a light modulus with a mass comparable to that of the gravitino which is typically much smaller than the Hubble parameter during inflation. Therefore, it is destabilized and generates a large late-time entropy when it decays. Thus, all known elegant mechanisms of generating the baryon asymmetry of the Universe in the literature have to take this fact into account.In this work, we find that it is still possible to naturally generate the observed baryon asymmetry of the Universe as well as light left-handed neutrino masses from a period of Affleck-Dine (AD) leptogenesis shortly after the end of inflation, in classes of realistic string constructions with a minimal extension of the MSSM below the unification scale (consisting only of right-handed neutrinos) and satisfying certain microscopic criteria described in the text. The AD mechanism has already been used to generate the baryon asymmetry in the literature; however in this work we have embedded the above mechanism within a framework well motivated from string theory and have tried to describe the epoch from the end of inflation to the beginning of BBN in a complete and self-consistent manner. The consequences of our analysis are as follows. The lightest left-handed neutrino is required to be virtually massless. The moduli (gravitino) problem can be naturally solved in this framework both within gravity and gauge mediation. The observed upper bound on the relic abundance constrains the moduli-matter and moduli-gravitino couplings since the DM is produced non-thermally within this framework. Finally, although not a definite prediction, the framework naturally allows a light right-handed neutrino and sneutrinos around the electroweak scale which could have important implications for the nature of DM as well as the LHC.

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Barygenesis without grand unification

Cited by 4,103 publications

References 14 publications

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

μ-term as the origin of baryon and lepton number asymmetry

Neutrino masses, Baryon asymmetry, dark matter and the moduli problem — A complete framework

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