Gravitational leptogenesis, reheating, and models of neutrino mass

Peter Adshead, Andrew J. Long, Evangelos I. Sfakianakis

Research output: Contribution to journalArticle

Abstract

Gravitational leptogenesis refers to a class of baryogenesis models in which the matter-antimatter asymmetry of the Universe arises through the standard model lepton-number gravitational anomaly. In these models chiral gravitational waves source a lepton asymmetry in standard model neutrinos during the inflationary epoch. We point out that gravitational leptogenesis can be successful in either the Dirac or Majorana neutrino mass scenario. In the Dirac mass scenario, gravitational leptogenesis predicts a relic abundance of sterile neutrinos that remain out of equilibrium, and the lepton asymmetry carried by the standard model sector is unchanged. In the Majorana mass scenario, the neutrinos participate in lepton-number-violating interactions that threaten to wash out the lepton asymmetry during postinflationary reheating. However, we show that a complete (exponential) washout of the lepton asymmetry is prevented if the lepton-number-violating interactions go out of equilibrium before all of the standard model Yukawa interactions come into equilibrium. The baryon and lepton asymmetries carried by right-chiral quarks and leptons are sequestered from the lepton-number violation, and the washout processes only suppress the predicted baryon asymmetry by a factor of μw.o.=±O(0.1). The sign of μw.o. depends on the model parameters in such a way that a future measurement of the primordial gravitational wave chirality would constrain the scale of lepton-number violation (heavy Majorana neutrino mass).

Original languageEnglish (US)
Article number043511
JournalPhysical Review D
Volume97
Issue number4
DOIs
StatePublished - Feb 12 2018

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leptons
neutrinos
heating
asymmetry
fallout
gravitational waves
baryons
antimatter
interactions
chirality
sectors
universe
time measurement
quarks
anomalies

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Gravitational leptogenesis, reheating, and models of neutrino mass. / Adshead, Peter; Long, Andrew J.; Sfakianakis, Evangelos I.

In: Physical Review D, Vol. 97, No. 4, 043511, 12.02.2018.

Research output: Contribution to journalArticle

Adshead, Peter ; Long, Andrew J. ; Sfakianakis, Evangelos I. / Gravitational leptogenesis, reheating, and models of neutrino mass. In: Physical Review D. 2018 ; Vol. 97, No. 4.
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