Year: 2026
Type: preprint
Abstract: An eV-scale sterile Majorana neutrino can suppress neutrinoless double-beta decay through destructive interference with the active-neutrino contribution, weakening the resulting constraints on sterile-neutrino parameters. We investigate how complementary beta-decay information restricts this cancellation in the 3+1 framework. Using updated oscillation parameters that include the first JUNO results, we determine the allowed sterile-neutrino mass and mixing regions for both normal and inverted ordering. We show that an upper limit on the effective beta-decay mass $m_β$ of the three light neutrinos strengthens the constraints from neutrinoless double-beta decay alone. The beta-decay bound restricts the light-neutrino masses and hence the cancellation between the active and sterile contributions to $m_{ββ}$. We derive analytic expressions for the resulting boundaries and use complex-plane geometry to explain the allowed values of the sterile Majorana phase $α_4$ for a finite $|m_{ββ}|$ limit. For the mixing considered, normal ordering allows a broad range of $α_4$ at small sterile masses, whereas inverted ordering favors values near $π$. The allowed phase range narrows as the sterile mass approaches its upper bound or the limit on $|m_{ββ}|$ becomes more stringent.
Source: arXiv (Cornell University)
Authors: Yang, Ruisha, Liao, Jiajun
Institution: Sun Yat-sen University
Language: English
Topic: Neutrino Physics Research
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221816131