Higgs boson mass bounds in the presence of a heavy fourth quark family

TL;DR

This paper uses lattice simulations to determine bounds on the Higgs boson mass in the presence of a heavy fourth quark family, with implications for LHC phenomenology.

Contribution

It introduces a non-perturbative lattice approach with a chiral invariant Higgs-Yukawa model to study Higgs mass bounds including a heavy fourth quark doublet.

Findings

Higgs mass bounds are established for quark masses up to 700 GeV.

The lower Higgs mass bound remains stable despite higher dimensional operators.

Results have significant implications for fourth-generation quark phenomenology at the LHC.

Abstract

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.