Modified Higgs Physics from Composite Light Flavors

TL;DR

This paper explores how composite light quarks in pNGB Higgs models can significantly alter Higgs decay rates into gauge bosons, providing a new way to probe flavor structure via LHC measurements.

Contribution

It demonstrates that light quarks' compositeness can cause order-one shifts in Higgs couplings, linking flavor structure to observable Higgs decay modifications.

Findings

Order-one shifts in Higgs couplings to gluons and photons due to light quark compositeness.

Current LHC Higgs decay measurements can indirectly probe the flavor structure of pNGB Higgs models.

The size of corrections is governed by the degree of light quark compositeness.

Abstract

We point out that Higgs rates into gauge bosons can be significantly modified in composite pseudo Nambu--Goldstone boson (pNGB) Higgs models if quarks belonging to the first two generation are relatively composite objects as well. Although the lightness of the latter a priori screen them from the electroweak symmetry breaking sector, we show, in an effective two-site description, that their partners can lead to order one shifts in radiative Higgs couplings to gluons and photons. Moreover, due to the pseudo-Goldstone nature of the Higgs boson, the size of these corrections is completely controlled by the degree of compositeness of the individual light quarks. The current measurements of flavor-blind Higgs decay rates at the LHC thus provide an indirect probe of the flavor structure of the framework of pNGB Higgs compositeness.