APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Philipp Schicho (U Helsinki)
Title: How to be precise at the electroweak scale at finite-temperature
Date: Wed, Nov 25, 2020, 16:00 - 17:00
Place: Zoom
Related File: 2573.pdf
Abstract: Based on recent investigations of the theoretical uncertainties of cosmological first-order phase transitions in [arXiv:2009.10080], this talk outlines how to improve precision at the electroweak scale at finite-temperature. Since thermal field theories exhibit a rigorous scale hierarchy, their bosonic sector is rendered non-perturbative in the infrared. Resummation for “soft" modes partially cures this "IR-problem". However, this approach is less systematic when advancing to two-loop level and suffers from renormalisation scale dependence even at one-loop for the effective potential.
As an alternative approach, I will motivate that at sufficiently high temperatures static observables are effectively described in a reduced dimension. This framework is known as Dimensional Reduction and -- as an EFT -- provides a systematic all-order thermal resummation. After constructing this "3d"-theory, I will demonstrate how to get hold of the effective potential in order to describe phase transitions in Beyond the Standard Model theories with extended Higgs sectors.