Fermion Masses and Mixings in a $μ$-$τ$ symmetric SO10 - High Energy Physics - PhenomenologyReport as inadecuate




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Abstract: $\mu$-$\tau$ symmetry imposed on the neutrino mass matrix in the flavourbasis is known to be quite predictive. We integrate this very specific neutrinosymmetry into a more general framework based on the supersymmetric SO10 grandunified theory. As in several other models, the fermion mass spectrum isdetermined by Hermitian mass matrices resulting from the renormalizable Yukawacouplings of the 16-plet of fermions with the Higgs fields transforming as $10,\bar{126},120$ representations of the SO10 group. The $\mu$-$\tau$ symmetryis spontaneously broken through the 120-plet. Consequences of this scheme areconsidered for fermion masses using both type-I and type-II seesaw mechanism.This scenario is shown to lead to a generalized CP invariance of the massmatrices and vanishing CP violating phases if the Yukawa couplings areinvariant under the $\mu$-$\tau$ symmetry. Small explicit breaking of the$\mu$-$\tau$ symmetry is then shown to provide a very good understanding of allthe fermion masses and mixing. Detailed fits to the fermion spectrum arepresented in several scenarios. One obtains a very good fit to all observablesin the context of the type-I seesaw mechanism but type-II seesaw model alsoprovides a good description except for the overall scale of the neutrinomasses. Three major predictions on the leptonic mixing parameters in the type-Iseesaw case are 1 the atmospheric mixing angle $\theta {23}^{l}$ close tomaximal, 2 $\theta {13}^{l}$ close to the present upper bound and 3negative but very small Dirac CP violating phase in the neutrino oscillations.



Author: Anjan S. Joshipura, Bhavik P. Kodrani, Ketan M. Patel

Source: https://arxiv.org/







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