Probing light-quark Yukawa couplings via hadronic event shapes at lepton colliders

TL;DR

This paper introduces a new method to measure light-quark Yukawa couplings by analyzing hadronic event shapes in Higgs decays at lepton colliders, offering a way to test Higgs interactions and QCD effects.

Contribution

It proposes a novel approach to probe light-quark Yukawa couplings using hadronic event shape distributions in Higgs decays at lepton colliders, which is a new testing technique.

Findings

Can exclude light-quark Yukawa couplings greater than 9% of bottom-quark Yukawa at CEPC

Provides a method to test Higgs couplings and QCD effects in Higgs decays

Enhances understanding of electroweak symmetry breaking mechanisms

Abstract

We propose a novel idea for probing the Higgs boson couplings through the measurement of hadronic event shape distributions in the decay of the Higgs boson at lepton colliders. The method provides a unique test of the Higgs boson couplings and of QCD effects in the decay of the Higgs boson. It can be used to probe the Yukawa couplings of the light quarks and to further test the mechanism of electroweak symmetry breaking. From a case study for the proposed Circular Electron-Positron Collider, assuming a hypothesis of SM-like theory, light-quark couplings with a strength greater than 9% of the bottom-quark Yukawa coupling in the standard model can be excluded.