Higgs-flavon mixing and LHC phenomenology in a simplified model of broken flavor symmetry

TL;DR

This paper investigates the collider phenomenology of a simplified broken flavor symmetry model featuring a new scalar and gauge boson, analyzing their effects on Higgs physics and potential detection at the LHC.

Contribution

It introduces a simplified model of broken flavor symmetry with a flavon and gauge boson, and explores their LHC signatures and constraints, including Higgs coupling modifications and flavon discovery prospects.

Findings

Flavon mass up to 500 GeV can be probed at 14 TeV with 100 fb$^{-1}$.

Constraints from heavy Higgs searches limit flavon properties.

Potential discovery channels include $Z^0Z^0$ and $hh$ final states.

Abstract

The LHC phenomenology of a low-scale gauged flavor symmetry model with inverted hierarchy is studied, through introduction of a simplified model of broken flavor symmetry. A new scalar (a flavon) and a new neutral top-philic massive gauge boson emerge with mass in the TeV range along with a new heavy fermion associated with the standard model top quark. After checking constraints from electroweak precision observables, we investigate the influence of the model on Higgs boson physics, notably on its production cross section and decay branching fractions. Limits on the flavon $\varphi$ from heavy Higgs boson searches at the LHC at 7 and 8 TeV are presented. The branching fractions of the flavon are computed as a function of the flavon mass and the Higgs-flavon mixing angle. We also explore possible discovery of the flavon at 14 TeV, particularly via the $\varphi \rightarrow Z^0Z^0$ decay channel in the $2\ell2\ell'$ final state, and through standard model Higgs boson pair production $\varphi \rightarrow hh$ in the $b\bar{b}\gamma\gamma$ final state. We conclude that the flavon mass range up to $500$ GeV could probed down to quite small values of the Higgs-flavon mixing angle with 100 fb$^{-1}$ of integrated luminosity at 14 TeV.