(No) Eternal Inflation and Precision Higgs Physics

TL;DR

This paper explores how precise measurements of the Higgs and top quark masses could determine whether our universe is in a metastable state that prevents eternal inflation, linking particle physics to cosmological fate.

Contribution

It identifies a narrow parameter window where Higgs physics can indicate the universe's ultimate fate, connecting collider measurements with cosmological implications.

Findings

A specific Higgs mass range implies a non-eternal inflation universe.

Precision measurements at colliders can test the metastability hypothesis.

Metastability in the MSSM could be directly probed at the TeV scale.

Abstract

Even if nothing but a light Higgs is observed at the LHC, suggesting that the Standard Model is unmodified up to scales far above the weak scale, Higgs physics can yield surprises of fundamental significance for cosmology. As has long been known, the Standard Model vacuum may be metastable for low enough Higgs mass, but a specific value of the decay rate holds special significance: for a very narrow window of parameters, our Universe has not yet decayed but the current inflationary period can not be future eternal. Determining whether we are in this window requires exquisite but achievable experimental precision, with a measurement of the Higgs mass to 0.1 GeV at the LHC, the top mass to 60 MeV at a linear collider, as well as an improved determination of alpha_s by an order of magnitude on the lattice. If the parameters are observed to lie in this special range, particle physics will establish that the future of our Universe is a global big crunch, without harboring pockets of eternal inflation, strongly suggesting that eternal inflation is censored by the fundamental theory. This conclusion could be drawn even more sharply if metastability with the appropriate decay rate is found in the MSSM, where the physics governing the instability can be directly probed at the TeV scale.