Singlet-Catalyzed Electroweak Phase Transitions in the 100 TeV Frontier

TL;DR

This paper explores the potential of a 100 TeV proton-proton collider to detect singlet scalar-driven strong first-order electroweak phase transitions through di-Higgs signals, showing significant extension of discovery reach over the LHC.

Contribution

It provides a detailed analysis of collider prospects for detecting singlet scalar effects related to electroweak phase transitions, including Monte Carlo scans and benchmark points.

Findings

Future colliders at 50-200 TeV can nearly fully discover the parameter space for strong first-order phase transitions.

Di-Higgs production signals are enhanced via singlet-Higgs mixing, aiding detection.

High-energy colliders significantly outperform the high luminosity LHC in probing these phenomena.

Abstract

We study the prospects for probing a gauge singlet scalar-driven strong first order electroweak phase transition with a future proton-proton collider in the 100 TeV range. Singlet-Higgs mixing enables resonantly-enhanced di-Higgs production, potentially aiding discovery prospects. We perform Monte Carlo scans of the parameter space to identify regions associated with a strong first-order electroweak phase transition, analyze the corresponding di-Higgs signal, and select a set of benchmark points that span the range of di-Higgs signal strengths. For the $b\bar{b}\gamma\gamma$ and $4\tau$ final states, we investigate discovery prospects for each benchmark point for the high luminosity phase of the Large Hadron Collider and for a future $pp$ collider with $\sqrt{s}$ = 50, 100, or 200 TeV. We find that any of these future collider scenarios could significantly extend the reach beyond that of the high luminosity LHC, and that with $\sqrt{s}$ = 100 TeV (200 TeV) and 30 ab$^{-1}$, the full region of parameter space favorable to strong first order electroweak phase transitions is almost fully (fully) discoverable.