CETUP* 2025

TALK: Decoupling Neutrino Magnetic Moment from Mass with SU(2)L Invariance

Jul 2, 2025, 10:45 AM

45m

Lead-Deadwood Elementary

Speaker

Anil Thapa (Colorado State University)

Description

Author: Anil Thapa
Abstract: Standard Model extensions that yield observable neutrino magnetic moments typically also induce large neutrino masses, incompatible with experimental limits. This tension motivates the search for mechanisms that naturally decouple magnetic moments from mass generation without requiring fine-tuning. In this talk, I will propose a novel mechanism for generating Dirac and Majorana neutrino magnetic moments, in which the associated mass contributions are forbidden by $SU(2{)}_L$ invariance. By carefully selecting the $SU(2{)}_L$ representations connecting to the loop diagram, we ensure that only the effective dipole operator involving the non-Abelian part of the photon -- the neutral gauge boson -- is generated. Crucially, the corresponding mass diagram, obtained by removing the external gauge boson leg, vanishes. We provide explicit UV completions that implement this mechanism and yield neutrino magnetic moments as large as from TeV-scale new physics.

Presentation materials

NMM_anil.pdf