Standard Model couplings and collider signatures of a light scalar

TL;DR

This paper investigates the properties and collider signatures of a light scalar particle arising from nearly scale-invariant electroweak symmetry breaking scenarios, highlighting potential new discovery channels and deviations from the Standard Model.

Contribution

It analyzes the couplings and collider signatures of a light scalar from nearly scale-invariant EWSB models, emphasizing differences from the minimal Standard Model.

Findings

Enhanced couplings to light fermions and gauge bosons.

Potential new decay channels into e^+e^- and mu^+mu^- pairs.

New production channels via light quark annihilation.

Abstract

The electroweak symmetry breaking (EWSB) sector of the Standard Model can be far richer and more interesting than the usual single scalar doublet model. We explore scenarios where the EWSB sector is nearly scale invariant and consequently gives rise to a light CP even scalar particle. The one-doublet SM is in that category, as are many other models with either weakly or strongly coupled sectors that trigger EWSB. We study the couplings of the light scalar to the SM particles that can arise from the explicit breaking of scale invariance focusing on the possible differences with the minimal SM. The couplings of the light scalar to light fermions, as well as to the massless gauge bosons, can be significantly enhanced. We find possible new discovery channels due to the decays of the conformal scalar into e^+e^- and mu^+mu^- pairs as well as new production channels via light quark annihilation.