Higgs Doublet Decay as the Origin of the Baryon Asymmetry

Thomas Hambye and Daniele Teresi
Phys. Rev. Lett. 117, 091801 – Published 25 August 2016

Abstract

We consider a question that curiously had not been properly considered thus far: in the standard seesaw model, what is the minimum value the mass of a right-handed (RH) neutrino must have for allowing successful leptogenesis via CP-violating decays? Answering this question requires us to take into account a number of thermal effects. We show that, for low RH neutrino masses, and thanks to these effects, leptogenesis turns out to proceed efficiently from the decay of the standard model scalar doublet components into a RH neutrino and a lepton. Such decays produce the asymmetry at low temperatures, slightly before sphaleron decoupling. If the RH neutrino has thermalized prior to producing the asymmetry, this mechanism turns out to lead to the bound mN>2GeV. If, instead, the RH neutrinos have not thermalized, leptogenesis from these decays is enhanced further and can be easily successful, even at lower scales. This Higgs-decay leptogenesis new mechanism works without requiring an interplay of flavor effects and/or cancellations of large Yukawa couplings in the neutrino mass matrix. Last but not least, such a scenario turns out to be testable, from direct production of the RH neutrino(s).

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  • Received 9 June 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.091801

© 2016 American Physical Society

Physics Subject Headings (PhySH)

Particles & Fields

Authors & Affiliations

Thomas Hambye* and Daniele Teresi

  • Service de Physique Théorique–Université Libre de Bruxelles, Boulevard du Triomphe, CP225, 1050 Brussels, Belgium

  • *thambye@ulb.ac.be
  • daniele.teresi@ulb.ac.be

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Issue

Vol. 117, Iss. 9 — 26 August 2016

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