Strong self-interactions among active neutrinos mediated by a neutrinophilic scalar is a well-motivated target of particle physics and cosmological probes. In this talk, I will give a brief overview of neutrino self-interactions and discuss their effect on precision electroweak data. First, I will present a simplified model where the finite radiative corrections are obtained with the guidance of gauge invariance. These corrections are logarithmically enhanced for small mediator masses. I will discuss the importance of neutrino charged-current coupling correction and its impact on the ∆r parameter and Fermi constant measurements. This effect was overlooked previously and allows us to derive the leading constraint on the neutrinophilic couplings for mediator mass above a few hundred MeV. Second, I will present a concrete UV completion which further includes a TeV-scale SU(2) triplet scalar and show the simplified model constraints continue to hold for a wide range of parameter space. These results serve as a useful roadmap for future explorations of the self-interacting neutrino paradigm.
IFIC seminar organizers