A minimal set of top-Higgs anomalous couplings

TL;DR

This paper simplifies the general form of fermion-fermion-Higgs interactions using equations of motion, identifying a minimal set of anomalous couplings relevant for off-shell particles in effective field theories.

Contribution

It derives a minimal, non-redundant set of top-Higgs anomalous couplings expressed solely with scalar and pseudo-scalar terms, simplifying the effective interaction vertices.

Findings

Reduced the number of relevant operators for Hf_i f_j interactions.

Explicit expressions for Htt and Htq vertices in terms of gauge-invariant operators.

Simplified the operator basis for Ztq interactions.

Abstract

We use the equations of motion to simplify the general form of fermion-fermion-Higgs interactions generated by dimension-six gauge-invariant effective operators. After removing redundant operators it is found that the most general H f_i f_j vertex for off-shell fermions f_i, f_j and an off-shell Higgs boson only involves scalar and pseudo-scalar terms, without derivatives. Examples are presented for the Htt and Htq interactions, where q=u,c, giving the explicit expressions of the vertices in terms of gauge-invariant operators. The new operator equalities obtained here also reduce the number of operators relevant for the Ztq vertices, although the general form of these interactions is not simplified with respect to previous results.