Observable Effects of General New Scalar Particles

TL;DR

This paper classifies all possible new scalar particles with renormalizable couplings to the Standard Model, computes their effects on the effective Lagrangian, and derives constraints on their properties from collider data.

Contribution

It provides a comprehensive classification and effective Lagrangian computation for new scalar particles coupled to the Standard Model, extending previous analyses.

Findings

Complete classification of scalar particles with linear couplings

Derivation of flavor-preserving constraints on couplings and masses

Full tree-level matching of effective operators to scalar extensions

Abstract

We classify all possible new scalar particles that can have renormalizable linear couplings to Standard Model fields and therefore be singly produced at colliders. We show that this classification exhausts the list of heavy scalar particles that contribute at the tree level to the Standard Model effective Lagrangian to dimension six. We compute this effective Lagrangian for a general scenario with an arbitrary number of new scalar particles and obtain flavor-preserving constraints on their couplings and masses. This completes the tree-level matching of the coefficients of dimension five and six operators in the effective Lagrangian to arbitrary extensions of the Standard Model.