arXiv Analytics

Sign in

arXiv:2007.04291 [hep-ph]AbstractReferencesReviewsResources

Large Neutrino Magnetic Moments in the Light of Recent Experiments

K. S. Babu, Sudip Jana, Manfred Lindner

Published 2020-07-08Version 1

The excess in electron recoil events reported recently by the XENON1T experiment may be interpreted as evidence for a sizable transition magnetic moment $\mu_{\nu_e\nu_\mu}$ of Majorana neutrinos. We show the consistency of this scenario when a single component transition magnetic moment takes values $\mu_{\nu_e\nu_\mu} \in(1.91 - 3.96) \times 10^{-11} \mu_B$. Such a large value usually leads to unacceptably large neutrino masses. In this paper we show that new symmetries systematically solve this problem and we demonstrate this by discussing a few examples. We first revive and then propose a simplified model based on $SU(2)_H$ horizontal symmetry which solves this problem. Owing to the difference in their Lorentz structures, in the $SU(2)_H$ symmetric limit, $m_\nu$ vanishes while $\mu_{\nu_e\nu_\mu}$ is nonzero. Our simplified model is based on an approximate $SU(2)_H$, which we also generalize to a three family $SU(3)_H$-symmetry. Collider and low energy tests of these models are analyzed. We also suggest a mechanism to evade stringent astrophysical limits on neutrino magnetic moments arising from stellar evolution by inducing a medium-dependent mass for the neutrino. We have also analyzed implications of the XENON1T data for the Zee model and its extensions which naturally generate a large $\mu_{\nu_e\nu_\mu}$ with suppressed $m_\nu$ via a spin symmetry mechanism, but found that the induced $\mu_{\nu_e\nu_\mu}$ is not large enough to explain recent data.

Related articles: Most relevant | Search more
arXiv:1007.4956 [hep-ph] (Published 2010-07-28, updated 2010-07-30)
New experiments with antiprotons
arXiv:hep-ph/0005095 (Published 2000-05-10, updated 2000-05-25)
Discovery of Proton Decay: A Must for Theory, a Challenge for Experiment
arXiv:hep-ph/0611005 (Published 2006-11-01)
QCD, New Physics and Experiment