Constraining the flavor changing Higgs couplings to the top-quark at the LHC

TL;DR

This paper investigates flavor-changing Higgs-top couplings at the LHC, identifying the most sensitive processes and providing upper bounds based on existing data, thereby constraining new physics beyond the Standard Model.

Contribution

It introduces a comprehensive analysis of flavor-changing Higgs couplings using multiple LHC processes and establishes the most stringent bounds from current data.

Findings

Process (c) yields the best upper bounds on flavor-changing couplings.

Upper bounds are approximately 4.2 x 10^{-3} at 7 TeV and 1.7 x 10^{-3} at 8 TeV.

Existing data constrains flavor-changing Higgs interactions more tightly than previous estimates.

Abstract

We study the flavor-changing couplings of the Higgs-boson with the top-quark using the processes: (a) pp --> tt, (b) pp --> t_bar j, and, (c) pp --> t_bar j h at the LHC in light of current discovery of a 126 GeV Higgs-Boson. Sensitivities for the flavor-changing couplings are estimated using the LHC data that was collected until spring 2013. It is found that the process (c) is the most capable of yielding the best upper bound on the flavor-changing couplings with 2 sigma level sensitivities of {|xi_{tc}^2 + xi_{tu}^2|}^{1/2} <= 4.2 x 10^{-3} and <= 1.7 x 10^{-3} resulting from t --> b l nu_l, h --> jj with the 7 TeV and 8 TeV centre-of-mass energies respectively using existing data from the LHC. The corresponding bounds from h --> b b_bar are worse by a factor of about 1.8.