SUSY induced top quark FCNC decay $t\to ch$ after Run I of LHC

Abstract

In light of the Higgs discovery and the nonobservation of sparticles at the LHC, we revisit the SUSY induced top quark flavor changing decay into the Higgs boson. We perform a scan over the relevant SUSY parameter space by considering the constraints from the Higgs mass measurement, the LHC search for SUSY, the vacuum stability, the precision electro-weak observables as well as $B\to X_s\gamma$. We have the following observations: (1) In the MSSM, the branching ratio of $t\to ch$ can only reach $3.0\times 10^{-6}$, which is about one order smaller than previous results obtained before the advent of the LHC. Among the considered constraints, the Higgs mass and the LHC search for sparticles are found to play an important role in limiting the prediction. (2) In the singlet extension of the MSSM, since the squark sector is less constrained by the Higgs mass, the branching ratio of $t\to ch$ can reach the order of $10^{-5}$ in the allowed parameter space. (3) The chiral-conserving mixings ${\delta }_{LL}$ and ${\delta }_{RR}$ may have remanent effects on $t\to ch$ in heavy SUSY limit. In the MSSM with squarks and gluino above 3 TeV and meanwhile the CP-odd Higgs boson mass around 1 TeV, the branching ratio of $t\to ch$ can still reach the order of $10^{-8}$ under the constraints.

20 pages. 3 figures

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• SUSY-induced FCNC top-quark processes at the Large Hadron Collider
• Light non-degenerate squarks at the LHC
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• Slim SUSY
• Constraints on flavor-changing neutral-current $Htq$ couplings from the signal of $tH$ associated production with QCD next-to-leading order accuracy at the LHC

Cited by in corpus (15)

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• Probing the top-Higgs boson FCNC couplings via the $h\to \gamma \gamma$ channel at the HE-LHC and FCC-hh
• Searches for anomalous $tqZ$ couplings from the trilepton signal of $tZ$ associated production at the 14 TeV LHC
• Search for top quark flavour changing neutral currents in same-sign top quark production
• Searches for the FCNC couplings from top-Higgs associated production signal with $h\to \gamma \gamma$ at the LHC
• Search for flavour-changing neutral-current couplings between the top quark and the Higgs boson in multi-lepton final states in 13 TeV $pp$ collisions with the ATLAS detector
• Search for a new scalar resonance in flavour-changing neutral-current top-quark decays $t\to qX$ ($q=u,c$), with $X\to b\bar{b}$, in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Search for flavor-changing neutral $tqH$ interactions with $H\to \gamma \gamma$ in $pp$ collisions at $\sqrt{s}$ = 13 TeV using the ATLAS detector
• Loop induced top quark FCNC through top quark and dark matter interactions
• Search for flavour-changing neutral current interactions of the top quark and the Higgs boson in events with a pair of $\tau$-leptons in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Rare top-quark decays $t\to cg(g)$ in the aligned two-Higgs-doublet model
• Search for flavor-changing neutral current interactions of the top quark mediated by a Higgs boson in proton-proton collisions at 13 TeV
• Investigating Top-Higgs FCNC Couplings at the FCC-hh