Light Quark Yukawa Couplings and the W±h Charge Asymmetry

Abstract

I review the recent theory progress on possibly measuring the light quark couplings, emphasizing the distinction between direct and indirect measurements. I highlight the importance of the W±h charge asymmetry measurement as a direct probe of enhanced light quark Yukawa couplings. I propose the W±h→ℓ±ℓ±qq′νν final state as a promising channel for measuring the charge asymmetry. This clean, same-sign dilepton final state should reach statistical discovery sensitivity in each W±h charge mode with 300 fb-1 of Large Hadron Collider luminosity, and affords an impressive sub-percent statistical accuracy with the anticipated 3 ab-1 high luminosity upgrade. After accounting for current direct constraints on the total Higgs width, the W±h charge asymmetry could deviate from the Standard Model expectation by tens of percent. The measurement of a non-Standard Model asymmetry would hence provide strong indications of enhanced light quark Yukawa couplings.