https://doi.org/10.1140/epjc/s10052-025-15057-1
Regular Article - Theoretical Physics
Impact of non-thermal leptogenesis with early matter domination on gravitational waves from first-order phase transition
1
School of Physical Sciences, Indian Association for the Cultivation of Science, 700032, Kolkata, India
2
Faculty of Physics, Institute of Theoretical Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
3
Department of Physics, PES Institute of Technology and Management, Sagar Road, 577204, Shivamogga, Karnataka, India
4
Department of Physics, University of Alabama, 35487, Tuscaloosa, AL, USA
a
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Received:
29
September
2025
Accepted:
8
November
2025
Published online:
31
December
2025
Abstract
We study the impact of non-thermal leptogenesis on the spectrum of gravitational waves (GWs) produced by a strong first-order phase transition in the early Universe. We consider a scenario in which a heavy scalar field, 
, dominates the energy density of the early Universe and decays into heavy right-handed neutrinos (RHNs). The subsequent decay of RHNs generates a lepton asymmetry, which is partially converted into the observed baryon asymmetry via the sphaleron process. The -dominated era and the entropy injection from the decays of and RHNs leave characteristic imprints on the GW spectrum, such as damping and modified frequency dependence, that distinguish it from the standard cosmological evolution. We identify the parameter space in which non-thermal leptogenesis is successful, leading to distinctive GW spectral features. We show that these GW signals can fall within the sensitivity ranges of future detectors such as ET, DECIGO and BBO. If observed, they would provide valuable insights into the thermal history and dynamics of the early Universe.
© The Author(s) 2025
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Funded by SCOAP3.
