Light composite scalar in twelve-flavor QCD on the lattice

TL;DR

This study uses lattice simulations to identify a light scalar particle in twelve-flavor QCD, suggesting its potential as a composite Higgs boson within conformal or walking technicolor frameworks.

Contribution

It provides evidence for a light flavor-singlet scalar in twelve-flavor QCD, linking its mass to infrared conformality and implications for composite Higgs models.

Findings

Scalar lighter than pion observed in lattice correlators

Scalar state linked to infrared conformality

Supports the technidilaton hypothesis in walking technicolor

Abstract

Based on lattice simulations using highly improved staggered quarks for twelve-flavor QCD with several bare fermion masses, we observe a flavor-singlet scalar state lighter than the pion in the correlators of fermionic interpolating operators. The same state is also investigated using correlators of gluonic interpolating operators. Combined with our previous study, that showed twelve-flavor QCD to be consistent with being in the conformal window, we infer that the lightness of the scalar state is due to infrared conformality. This result shed some light on the possibility of a light composite Higgs boson ("technidilaton") in walking technicolor theories.