The Standard Model cross-over on the lattice

TL;DR

This paper uses lattice Monte Carlo simulations to study the thermodynamics of the Standard Model's smooth cross-over transition at the physical Higgs mass, providing precise measurements of thermodynamic quantities and the cross-over temperature.

Contribution

It presents improved non-perturbative lattice results for the Standard Model cross-over, including thermodynamic measurements and the cross-over temperature with high precision.

Findings

Cross-over width is approximately 5 GeV.

Cross-over temperature is $159.5 \, ext{GeV}$ with 1.5 GeV uncertainty.

Perturbative results agree with non-perturbative ones outside the cross-over region.

Abstract

With the physical Higgs mass the Standard Model symmetry restoration phase transition is a smooth cross-over. We study the thermodynamics of the cross-over using numerical lattice Monte Carlo simulations of an effective SU(2) X U(1) gauge + Higgs theory, significantly improving on previously published results. We measure the Higgs field expectation value, thermodynamic quantities like pressure, energy density, speed of sound and heat capacity, and screening masses associated with the Higgs and Z fields. While the cross-over is smooth, it is very well defined with a width of only approximately 5 GeV. We measure the cross-over temperature from the maximum of the susceptibility of the Higgs condensate, with the result $T_c = 159.5 \pm 1.5$ GeV. Outside of the narrow cross-over region the perturbative results agree well with non-perturbative ones.