$e^+e^- \to t \bar t H$ with Non-standard Higgs Boson Couplings

TL;DR

This paper investigates how non-standard Higgs couplings to top quarks can be constrained using the process e+e- -> t t-bar H at future linear colliders with high energy and luminosity.

Contribution

It introduces a general effective Lagrangian including CP violation for Higgs-top couplings and analyzes their detectability at future linear colliders.

Findings

Non-standard couplings can be probed with high sensitivity at future colliders.

Constraints from Z -> b b-bar data limit some coupling parameters.

High luminosity enhances the detection prospects of non-standard effects.

Abstract

We consider a general effective Lagrangian for couplings of a Higgs boson to the top-quark to dimension-six operators including CP violation effects. Constraints on some of them are derived from the $Z\to b\bar b$ data. We study the process $e^+e^- \to t\bar t H$ to probe the non-standard couplings. We find that at a linear collider with a c. m. energy $\sqrt s \sim 0.5-1.5$ TeV and a high luminosity of 10-1000 fb$^{-1}$, these non-standard couplings may be sensitively probed.