EPJ

2023 Impact factor 4.2
EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 14, 85-89
DOI 10.1007/s100520000299

Vacuum solutions of neutrino anomalies through a softly broken U(1) symmetry

A.S. Joshipura - S.D. Rindani

Theoretical Physics Group, Physical Research Laboratory, Navarangpura, Ahmedabad, 380 009, India

Received: 5 August 1999 / Revised version: 18 November 1999 /
Published online: 6 April 2000 - © Springer-Verlag 2000

Abstract
We discuss an extended $SU(2)\times U(1)$ model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies in terms of the vacuum oscillations of the three known neutrinos. The model uses a softly broken Le-$L_\mu$-$L_{\tau}$symmetry and contains a heavy scale $M_H\sim 10^{15}\,{\mathrm {GeV}}$. The Le-$L_\mu$-$L_{\tau}$symmetric neutrino masses solve the atmospheric neutrino anomaly while breaking of Le-$L_\mu$-$L_{\tau}$generates the highly suppressed radiative mass scale $\Delta_S\sim 10^{-10}\,{\mathrm {eV}}^2$ needed for the vacuum solution of the solar neutrino problem. All the neutrino masses in the model are inversely related to MH, thus providing seesaw-type of masses without invoking any heavy right-handed neutrinos. The possible embedding of the model into an SU(5)grand unified theory is discussed.

Copyright Società Italiana di Fisica, Springer-Verlag 2000

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