Phenomenology of Enhanced Light Quark Yukawa Couplings and the $W^\pm h$ Charge Asymmetry

TL;DR

This paper proposes measuring the $W^ h$ charge asymmetry at the LHC as a novel way to test for enhanced light quark Yukawa couplings, providing a precise method to verify the Standard Model Higgs properties.

Contribution

It introduces a collider analysis for the $W^ h$ charge asymmetry in same-sign lepton final states, offering a new experimental probe for light quark Yukawa couplings beyond existing constraints.

Findings

Charge asymmetry measurement can reach 0.4% precision with 3 ab$^{-1}$ luminosity.

The method provides a direct test of light quark Yukawa couplings.

Enhanced light quark Yukawas significantly increase the Higgs width, affecting global fits.

Abstract

I propose the measurement of the $W^\pm h$ charge asymmetry as a consistency test for the Standard Model (SM) Higgs, which is sensitive to enhanced Yukawa couplings of the first and second generation quarks. I present a collider analysis for the charge asymmetry in the same-sign lepton final state, $p p \to W^\pm h \to (\ell^\pm \nu) (\ell^\pm \nu jj)$, aimed at discovery significance for the SM $W^\pm h$ production mode in each charge channel with 300 fb$^{-1}$ of 14 TeV LHC data. Using this decay mode, I estimate the statistical precision on the charge asymmetry should reach 0.4\% with 3 ab$^{-1}$ luminosity, enabling a strong consistency test of the SM Higgs hypothesis. I also discuss direct and indirect constraints on light quark Yukawa couplings from direct and indirect probes of the Higgs width as well as Tevatron and Large Hadron Collider Higgs data. While the main effect from enhanced light quark Yukawa couplings is a rapid increase in the total Higgs width, such effects could be mitigated in a global fit to Higgs couplings, leaving the $W^\pm h$ charge asymmetry as a novel signature to test directly the Higgs couplings to light quarks.