Probing the top-Higgs boson FCNC couplings via the h→γγ channel at the HE-LHC and FCC-hh

• Published in: Physical review. D 2020-04, Vol.101 (7), p.1
• Main Authors: Liu, Yao-Bei, Moretti, Stefano
• Format: Article
• Language: English
• Subjects: Confidence intervals; Couplings; Flavor (particle physics); Higgs bosons; Large Hadron Collider; Luminosity; Neutral currents; Pair production; Quarks; Superconducting supercolliders
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.101.075029

We investigate the sensitivity of future searches for the top-Higgs boson flavor changing neutral current (FCNC) couplings t q h (q = u, c) at the proposed High Energy Large Hadron Collider (HE-LHC) and Future Circular Collider in the hadron-hadron mode (FCC-hh). We perform a full simulation for the two processes in the h → γ γ decay channel (where h is the discovered Higgs boson state): the single top quark FCNC production in association with the Higgs boson (plus a jet) and the top quark pair production with FCNC decays t → q h . All the relevant backgrounds are considered in a cut based analysis to obtain the limits on the branching ratios (BRs) of t → u h and t → c h . It is shown that, at the HE-LHC with an integrated luminosity of 15 ab−1 and at the FCC-hh with an integrated luminosity of 30 ab−1, the BR (t → uh) [BR (t → ch)] can be probed, respectively, to 7.0 ( 8.5 ) × 10−5 and 2.3 ( 3.0 ) × 10−5 at the 95% confidence level (C.L.) (assuming a 10% systematic uncertainty on the background), which is almost 2 orders of magnitude better than the current 13 TeV LHC experimental results.