Abstract
<jats:p>The Georgi–Machacek (GM) model extends the Standard Model (SM) Higgs sector by adding one complex and one real scalar triplet, while preserving a custodial SU(2)V symmetry. This setup predicts a rich scalar spectrum including a quintet, a triplet, and two CP-even singlets. In this article, we review the model structure, its mass spectrum, and the theoretical and experimental constraints from perturbativity, vacuum stability, electroweak precision tests, Higgs measurements, and direct searches at colliders in both cases where the SM-like Higgs should be the light or heavy CP-even eigenstate. We also discuss the model’s capability to explain the 95 GeV excess reported in γγ, ττ and b¯b channels, by assuming two degenerate (CP-even and CP-odd) resonances. We demonstrate that the nature of the 95 GeV scalar resonance candidate can be probed via the properties of its di-τ decay.</jats:p>