Charm-quark Yukawa coupling in h→cc¯γ 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 → bb) and the lack of an effective trigger for the signal h → cc. We examine the feasibility of probing this coupling at the LHC via a Higgs radiative decay h → ccγ. 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 2σ sensitivity after the High Luminosity LHC (HL-LHC). Our result is comparable and complementary to other projections for direct and indirect probes of h → cc 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.

Higgs to charm quarks in vector boson fusion plus a photon

“…3.2), to about 5 times the SM value at 95% CL s at HL-LHC. Our obtained constraint on charm-Yukawa coupling, summarized in Table 5, is better than the H → J/ψ + γ channel [28] and radiative decay of the Higgs boson [41]. Even though the limit obtained in our analyses is slightly weaker than the ZH direct search by ATLAS [17], our channel will provide complementary information and a combination of different search channels can further improve the limit.…”

“…It has also been proposed to constrain y c using Di-Higgs production [38,39]. There are proposals to further enhance the sensitivity of H → cc by utilizing an additional photon radiation [40][41][42].…”

Cancellation in Dark Matter-Nucleon Interactions: the Role of Non-Standard-Model-like Yukawa Couplings

“…However, with the high luminosity run of the LHC (HL-LHC), there could be some chance of probing them. In recent times, several possibilities have been explored for testing these couplings at the LHC [76,77,[108][109][110][111][112][113][114][115][116][117][118][119][120][121][122], especially for c and also for s-quarks, in parallel to the ongoing experimental efforts [123][124][125][126][127][128]. Some of these proposals consider looking at rare Higgs decays to light flavoured mesons (like J/ψ or φ , etc.)…”

Higgs boson decay to charmonia via $c$-quark fragmentation

“…At present, ATLAS and CMS give the upper limit on Higgs direct decay to charm quark mode of σ(pp → ZH) × BR(H → cc) < 2.7 pb and σ(V H) × BR(H → cc) < 4.5 pb, which are about 100 and 70 times greater than the SM prediction, respectively [20,21]. Many dedicated efforts have been made to tackle the problem from different directions [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], with limited successes.…”