- Open Access
Testing the seesaw mechanism and leptogenesis with gravitational waves: Majorana versus Dirac cases
Phys. Rev. D 113, 055050 – Published 30 March, 2026
DOI: https://doi.org/10.1103/zygj-4hhy
Abstract
We investigate the gauge extension of the Standard Model that the Dirac seesaw mechanism with thermal leptogenesis leaves imprints in the early Universe via the stochastic gravitational background emanating from a network of cosmic strings when symmetry is broken. With right-handed neutrino mass lighter than the typical scale of grand unification, the symmetry protecting the right-handed neutrinos leads to constraints on the Yukawa couplings for both Dirac and Majorana scenarios. Estimating the predicted gravitational wave background we find that future space-borne missions could probe the range concerning thermal Dirac leptogenesis. In a comparative analysis between such probes of gravitational waves sourced from cosmic strings in Dirac and Majorana leptogenesis in the extension, based on the energy scales of the leptogenesis, for instance, gravitational waves detectors will be able to probe the scale of Dirac leptogenesis up to , while for Majorana leptogenesis it would be upto .
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