Charm-quark Yukawa Coupling in $h\to c\bar{c}\gamma$ at LHC

Abstract

It is extremely challenging to probe the charm-quark Yukawa coupling at hadron colliders primarily due to the large Standard Model (SM) background (including $h\to b\bar{b}$) and the lack of an effective trigger for the signal $h\to c\bar{c}$. We examine the feasibility of probing this coupling at the LHC via a Higgs radiative decay $h\to c\bar{c}\gamma$. The existence of an additional photon in the final state may help for the signal identification and background suppression. Adopting a refined triggering strategy and utilizing basic machine learning, we find that a coupling limit of about 8 times the SM value may be reached with $2\sigma$ sensitivity after the High Luminosity LHC (HL-LHC). Our result is comparable and complementary to other projections for direct and indirect probes of $h\to c\bar{c}$ at the HL-LHC. Without a significant change in detector capabilities, there would be no significant improvement for this search from higher energy hadron colliders.

16 pages, 2 figures, 2 tables

References in corpus (10)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Particle-flow reconstruction and global event description with the CMS detector
• Pileup subtraction using jet areas
• Pileup Per Particle Identification
• A generic anti-QCD jet tagger
• Relativistic corrections to Higgs boson decays to quarkonia
• Search for Higgs and $Z$ Boson Decays to $J/\psi \gamma$ and ${\rm Y}(nS)\gamma$ with the ATLAS Detector
• Phenomenology of Enhanced Light Quark Yukawa Couplings and the $W^{\pm }h$ Charge Asymmetry
• Higgs Boson Decay to Light Jets at the LHC