Non-standard interactions in radiative neutrino mass models

Journal Article · 02 March 2020 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/JHEP03(2020)006 · OSTI ID:1556969

Babu, K. S.  ^[1]; Dev, P. S. Bhupal  ^[2]; Jana, Sudip  ^[1]; Thapa, Anil ^[1]

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1. Oklahoma City Univ., OK (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2. Washington Univ., St. Louis, MO (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

Models of radiative Majorana neutrino masses require new scalars and/or fermions to induce lepton-number-violating interactions. We show that these new particles also generate observable neutrino non-standard interactions (NSI) with matter. We classify radiative models as type-I or II, with type-I models containing at least one Standard Model (SM) particle inside the loop diagram generating neutrino mass, and type-II models having no SM particle inside the loop. While type-II radiative models do not generate NSI at tree-level, popular models which fall under the type-I category are shown, somewhat surprisingly, to generate observable NSI at tree-level, while being consistent with direct and indirect constraints from colliders, electroweak precision data and charged-lepton flavor violation (cLFV). We survey such models where neutrino masses arise at one, two and three loops. In the prototypical Zee model which generates neutrino masses via one-loop diagrams involving charged scalars, we find that diagonal NSI can be as large as (8%, 3.8%, 9.3%) for (ε$$_{ee}$$, ε$$_{μμ}$$, ε$$_{ττ}$$), while off-diagonal NSI can be at most (10$$^{–3}$$%, 0.56%, 0.34%) for (ε$$_{eμ}$$, ε$$_{eτ}$$, ε$$_{μτ}$$). In one-loop neutrino mass models using leptoquarks (LQs), (ε$$_{μμ}$$, ε$$_{ττ}$$) can be as large as (21.6%, 51.7%), while ε$$_{ee}$$ and (ε$$_{eμ}$$, ε$$_{eτ}$$, ε$$_{μτ}$$) can at most be 0.6%. Other two- and three-loop LQ models are found to give NSI of similar strength. The most stringent constraints on the diagonal NSI are found to come from neutrino oscillation and scattering experiments, while the off-diagonal NSI are mostly constrained by low-energy processes, such as atomic parity violation and cLFV. We also comment on the future sensitivity of these radiative models in long-baseline neutrino experiments, such as DUNE. While our analysis is focused on radiative neutrino mass models, it essentially covers all NSI possibilities with heavy mediators.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Contributing Organization: US Neutrino Theory Network Program; Fermilab Distinguished Scholar Program
• Grant/Contract Number: AC02-07CH11359; SC0016013; SC0017987
• OSTI ID: 1556969
• Report Number(s): arXiv:1907.09498; FERMILAB-PUB-19-304-T; OSU-HEP-19-04; oai:inspirehep.net:1745937
• Journal Information: Journal of High Energy Physics (Online), Vol. 2020, Issue 3; ISSN 1029-8479
• Publisher: Springer BerlinCopyright Statement
• Country of Publication: United States
• Language: English