Warped Alternatives to Froggatt-Nielsen Models

TL;DR

This paper explores a Randall-Sundrum framework as a flavor model alternative to Froggatt-Nielsen, fitting fermion masses and mixing angles at the GUT scale, and analyzing neutrino mass scenarios and supersymmetric extensions.

Contribution

It introduces a modified RS setup at the GUT scale for flavor physics, fitting fermion data and analyzing neutrino mass mechanisms and supersymmetric implications.

Findings

Both neutrino mass scenarios fit data well, with lepton number violation slightly better.

Heavy top quark requires large bulk mass parameters near the IR brane.

Squark masses around 2-3 TeV satisfy Higgs mass and flavor constraints.

Abstract

We consider Randall-Sundrum set up (RS) to be a theory of flavour, as an alternative to Froggatt-Nielsen models instead of as a solution to the hierarchy problem. We consider a modified RS framework between the Planck scale and the GUT scale. This also alleviates constraints from flavour physics. Fermion masses and mixing angles are fit at the GUT scale. The ranges of the bulk mass parameters are determined using a $\chi^2$ fit taking in to consideration the variation in $\mathcal{O}(1)$ parameters. In the hadronic sector, the heavy top quark requires large bulk mass parameters localising the right handed top quark close to the IR brane. Two cases of neutrino masses are considered (a) Planck scale lepton number violation and (b) Dirac neutrino masses. Contrary to the case of weak scale RS models, both these cases give reasonable fits to the data, with the Planck scale lepton number violation fitting slightly better compared to the Dirac case. In the Supersymmetric version, the fits are not significantly different except for the variation in $\tan\beta$. If the Higgs superfield and the SUSY breaking spurion are localized on the same brane then the structure of the sfermion masses are determined by the profiles of the zero modes of the hypermultiplets in the bulk. Trilinear terms have the same structure as the Yukawa matrices. The resultant squark spectrum is around $\sim 2-3 \text{TeV}$ required by the light Higgs mass to be around 125 GeV and to satisfy the flavour violating constraints.