An operator basis for the Standard Model with an added scalar singlet

TL;DR

This paper develops a comprehensive operator basis for the Standard Model extended with a scalar singlet at dimensions 5, 6, and 7, correcting previous redundancies and aiding new physics searches.

Contribution

It provides a complete, non-redundant set of effective operators for the SM plus a scalar singlet at higher dimensions, improving theoretical tools for beyond Standard Model physics.

Findings

Identifies and removes redundancies in existing operator bases.

Constructs a basis at dimensions 5, 6, and 7 for the SM with a scalar singlet.

Facilitates future phenomenological studies of scalar singlet extensions.

Abstract

Motivated by the possible di-gamma resonance at 750 GeV, we present a basis of effective operators for the Standard Model plus a scalar singlet at dimensions 5, 6, and 7. We point out that an earlier list at dimensions 5 and 6 contains two redundant operators at dimension 5.