Direct constraints on the top-Higgs coupling from the 8 TeV LHC data

TL;DR

This paper reanalyzes 8 TeV LHC data to provide direct constraints on the top-Higgs coupling, using Higgs-top associated production and decay signatures to improve sensitivity to anomalous couplings.

Contribution

It introduces a new analysis method focusing on Higgs-top associated production to better constrain the top-Higgs coupling, especially its sign and magnitude.

Findings

Strong destructive interference enhances sensitivity to anomalous couplings.

Combination of di-photon and multi-lepton signatures improves constraints.

Potential to exclude large negative top-Higgs coupling regions.

Abstract

The LHC experiments have analyzed the 7 and 8 TeV LHC data in the main Higgs production and decay modes. Current analyses only loosely constrain an anomalous top-Higgs coupling in a direct way. In order to strongly constrain this coupling, the Higgs-top associated production is reanalyzed. Thanks to the strong destructive interference in the t-channel for standard model couplings, this process can be very sensitive to both the magnitude and the sign of a non-standard top-Higgs coupling. We project the sensitivity to anomalous couplings to the integrated luminosity of 50 fb^{-1}, corresponding to the data collected by the ATLAS and CMS experiments in 7 and 8 TeV collisions, as of 2012. We show that the combination of di-photon and multi-lepton signatures, originating from different combinations of the top and Higgs decay modes, can be a potential probe to constrain a large portion of the negative top-Higgs coupling space presently allowed by the ATLAS and CMS global fits.