High Energy Physics and Cosmology at the Unification Frontier: Opportunities and Challenges in the coming years

TL;DR

This paper reviews recent developments linking high energy physics and cosmology, emphasizing supersymmetry as a promising framework supported by empirical data, and discusses future experimental prospects at colliders and in neutrino, dark matter, and dark energy research.

Contribution

It provides a comprehensive overview of the current evidence for supersymmetry and explores future experimental opportunities to test unification theories.

Findings

Supersymmetry explains gauge coupling unification and Higgs mass predictions.

High energy colliders like HE-LHC can significantly extend discovery potential.

Upcoming experiments will impact the unification frontier in physics.

Abstract

We give here an overview of recent developments in high energy physics and cosmology and their interconnections that relate to unification, and discuss prospects for the future. Thus there are currently three empirical data that point to supersymmetry as an underlying symmetry of particle physics: the unification of gauge couplings within supersymmetry, the fact that nature respects the supersymmetry prediction that the Higgs boson mass lie below 130 GeV, and vacuum stability up to the Planck scale with a Higgs boson mass at $\sim 125$ GeV while the standard model does not do that. Coupled with the fact that supersymmetry solves the big hierarchy problem related to the quadratic divergence to the Higgs boson mass square along with the fact that there is no alternative paradigm that allows us to extrapolate physics from the electroweak scale to the grand unification scale consistent with experiment, supersymmetry remains a compelling framework for new physics beyond the standard model. The large loop correction to the Higgs boson mass in supersymmetry to lift the tree mass to the experimentally observable value, indicates a larger value of the scale of weak scale supersymmetry, making the observation of sparticles more challenging but still within reach at the LHC for the lightest ones. Recent analyses show that a high energy LHC (HE-LHC) operating at 27 TeV running at its optimal luminosity of $2.5 \times 10^{35}$ cm$^{-2}$s$^{-1}$ can reduce the discovery period by several years relative to HL-LHC and significantly extend the reach in parameter space of models. In the coming years several experiments related to neutrino physics, searches for supersymmetry, on dark matter and dark energy will have direct impact on the unification frontier.