Dark clouds to silver linings over the hyperchargeless scalar triplets

TL;DR

This paper examines scalar triplet models extending the Standard Model, analyzing their potential for dark matter, symmetry breaking, phase transitions, gravitational waves, and collider signals under current constraints.

Contribution

It provides a comparative analysis of inert and non-inert triplet models, highlighting their trade-offs and phenomenological signatures in dark matter and phase transition contexts.

Findings

Trade-off between dark matter viability and first-order phase transition

Potential gravitational wave signals from phase transitions

Distinct collider signatures for inert and non-inert triplet models

Abstract

A real scalar triplet with zero hypercharge offers a minimal non-trivial extension of the Standard Model (SM) with a charged Higgs and a possible dark matter or custodial symmetry breaking signature. The $Z_2$-odd inert triplet model (ITM) provides a dark matter, while the non-inert Higgs triplet model (HTM) breaks the custodial symmetry, enabling rich collider signatures. Both these models also promise the viability of a first-order phase transition (FOPT). This letter revisits both models under various theoretical and current experimental constraints, revealing a trade-off between DM and FOPT viability, and explores the resulting gravitational wave signals and collider prospects.