Speaker
Description
In this poster, I will analyze the potential signatures of a first-order electroweak phase transition in the early Universe. Since the Standard Model does not allow for such a transition, I will explore a simple extension of the scalar sector—the Two Higgs Doublet Model (2HDM)—which introduces a second Higgs doublet.
If the phase transition is strong enough, it proceeds via the spontaneous nucleation of bubbles of the electroweak vacuum. The collisions of these bubbles can generate a stochastic gravitational wave background, potentially detectable by LISA.
I will focus on two key probes of this scenario: collider searches and cosmological signals. On the collider side, I will discuss recent ATLAS searches for $A \to ZH$
decays in $\ell^+ \ell^- t \bar{t}$ and $\nu \nu b \bar{b}$ final states. Additionally, I will explore the complementarity of these searches with other LHC analyses and examine the interplay between collider experiments and space-based gravitational wave detectors.
