Sterile neutrinos with non-standard interactions in β- and 0νββ-decay experiments

Tritium beta-decay is the most promising approach to measure the absolute masses of active light neutrinos in the laboratory and in a model-independent fashion. The development of Cyclotron Radiation Emission Spectroscopy techniques and the use of atomic tritium has the potential to improve the current limits by an order of magnitude in future experiments. In this paper, we analyse the potential sensitivity of such future searches to keV-mass sterile neutrinos and exotic interactions of either the active or sterile neutrinos. We calculate the relevant decay distributions in both energy and angle of the emitted electron with respect to a potential polarisation of the tritium, including the interference with the Standard Model case as well as incorporating relevant final state corrections for atomic tritium. We present projected sensitivities on the active-sterile neutrino mixing and effective coupling constants of exotic currents, demonstrating the potential to probe New Physics in tritium experiments.

Section: Jhep03(2023)144mentioning

confidence: 99%

Sensitivity of future tritium decay experiments to New Physics

Deppisch

Wenna

2023

“…We apply SU(3) chiral EFT extended with sterile neutrinos to describe LNV kaon decays in this mass regime. Such neutrinos can be looked for in many different experiments, ranging from oscillation to beta-decay to collider experiments [29][30][31][32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Light sterile neutrinos and lepton-number-violating kaon decays in effective field theory

Zhou

2022

We investigate lepton-number-violating decays K∓ → π±l∓l∓ in the presence of sterile neutrinos. We consider minimal interactions with Standard-Model fields through Yukawa couplings as well as higher-dimensional operators in the framework of the neutrino-extended Standard Model Effective Field Theory. We use SU(3) chiral perturbation theory to match to mesonic interactions and compute the lepton-number-violating decay rate in terms of the neutrino masses and the Wilson coefficients of higher-dimensional operators. For neutrinos that can be produced on-shell, the decay rates are highly enhanced and higher-dimensional interactions can be probed up to very high scales around $$ \mathcal{O} $$ O (30) TeV.

“…. For the first-generation charged fermions, such operators contribute, among other processes, to neutrinoless double beta decay[45][46][47][48].…”

mentioning

confidence: 99%

Long-lived heavy neutral leptons from mesons in effective field theory

Beltrán

Cottin

Helo

et al. 2023

In the framework of the low-energy effective field theory of the Standard Model extended with heavy neutral leptons (HNLs), we calculate the production rates of HNLs from meson decays triggered by dimension-six operators. We consider both lepton-number-conserving and lepton-number-violating four-fermion operators involving either a pair of HNLs or a single HNL. Assuming that HNLs are long-lived, we perform simulations and investigate the reach of the proposed far detectors at the high-luminosity LHC to (i) active-heavy neutrino mixing and (ii) the Wilson coefficients associated with the effective operators, for HNL masses below the mass of the B-meson. We further convert the latter to the associated new-physics scales. Our results show that scales in excess of hundreds of TeV and the active-heavy mixing squared as small as 10−15 can be probed by these experiments.