https://doi.org/10.1140/epjc/s10052-025-14487-1
Regular Article - Theoretical Physics
Insights on the scale of leptogenesis from neutrino masses and neutrinoless double-beta decay
1
Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126, Bologna, Italy
2
Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, viale Berti Pichat 6/2, 40127, Bologna, Italy
3
Department of Physics, University of Tokyo, Bunkyo-ku, 113–0033, Tokyo, Japan
4
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), University of Tokyo, 277–8583, Kashiwa, Japan
5
PRISMA+ Cluster of Excellence, Johannes Gutenberg University, 55099, Mainz, Germany
6
Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, 606-8502, Kyoto, Japan
a
tyokoyama@hep-th.phys.s.u-tokyo.ac.jp
Received:
25
February
2025
Accepted:
2
July
2025
Published online:
17
July
2025
We revisit the thermal leptogenesis scenario in the type-I seesaw framework featuring three heavy Majorana neutrinos with a hierarchical mass spectrum. We focus on low energy observables, specifically the lightest neutrino mass 
and the neutrinoless double-beta decay effective mass parameter 
. In particular, we numerically calculate the minimum mass of the lightest heavy Majorana neutrino, 
, required for successful leptogenesis as a function of and 
, considering both normal and inverted light neutrino mass orderings. Flavour effects are taken into account within the flavoured density matrix formalism. We also examine the interplay between fine-tuned cancellations in the seesaw relation and . Recent and forthcoming searches for neutrinoless double-beta decay, along with cosmological probes of the sum of neutrino masses, motivate this analysis, as they can provide key insights into the minimal scale of thermal leptogenesis and its broader implications.
© The Author(s) 2025
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Funded by SCOAP3.
