arXiv subjects

J. Klarić

Publications and source records attributed to J. Klarić.

2 recordsLinked to original sources

arXiv2025

Confronting the low-scale seesaw and leptogenesis with neutrinoless double beta decay

We revisit the impact of heavy neutrinos with masses in the MeV-GeV range on neutrinoless double beta decay ($0νββ$) in view of updated results for the lifetime of this process. Working in a minimal realistic extension of the Standard Model by two right-handed neutrino flavours, we show that the non-observation of $0νββ$ will impose strong bounds on the heavy neutrino properties that are complementary to the limits obtained from Big Bang Nucleosynthesis and collider searches. For an inverted mass hierarchy of the light neutrinos we find that improved limits on $0νββ$ from next-generation experiments, assuming an improvement of two orders of magnitude on the current $0νββ$ limits will restrict the allowed parameter space for fixed mass splitting to narrow bands in the mass-mixing plane. Further combining this with the requirement to explain the baryon asymmetry of the universe via leptogenesis reduces these bands to windows in parameter space that are constrained in all directions and can be targeted by direct searches at accelerators, and restricts the mass splitting to values that can be resolved at experiments. For a normal mass hierarchy, restricting the allowed parameter will require even stronger $0νββ$ limits, and only parts of the parameter space can then be probed.

hep-ph↗

arXiv2023

Tests of Low-Scale Leptogenesis in Charged Lepton Flavour Violation Experiments

We consider low-energy tests of low-scale leptogenesis based on the type I seesaw scenario with three right-handed singlet neutrinos $ν_{l R}$. In this scenario, successful leptogenesis is possible for quasi-degenerate in mass heavy Majorana neutrinos $N_{1,2,3}$, $M_{1,2,3}\cong M$, $|M_j - M_i|\ll M$, $i\neq j = 1,2,3$, heavy Majorana neutrino masses $M \sim (0.05 - 5\times 10^5)$ GeV, and $N_j$ charged current and neutral current weak interaction couplings as large as $\mathcal{O}(10^{-2})$. We derive the constraints on the corresponding leptogenesis parameter space from the existing data from low-energy experiments, including the limits from the experiments on $μ\rightarrow e γ$ decay and on the rate of $μ- e$ conversion in gold. We show also that the planned and upcoming experiments on charged lepton flavour violation with $μ^\pm$, MEG II on the $μ\rightarrow eγ$ decay, Mu3e on $μ\rightarrow eee$ decay, Mu2e and COMET on $μ- e$ conversion in aluminium and PRISM/PRIME on $μ- e$ conversion in titanium, can probe significant region of the viable leptogenesis parameter space, and thus have a potential for a discovery. Experiments on $τ\to eee(μμμ)$ and $τ\to e(μ)γ$ decays (e.g., BELLE II) also can probe a part of the leptogenesis parameter space, although a relatively small one.

hep-ph↗