On the validity of perturbative studies of the electroweak phase transition in the Two Higgs Doublet model

• Main Authors: Kimmo Kainulainen, Venus Keus, Lauri Niemi, Kari Rummukainen, Tuomas V. I. Tenkanen, Ville Vaskonen
• Format: Article
• Language: English
• Published: SpringerOpen 2019-06-01
• Series: Journal of High Energy Physics
• Subjects: Effective Field Theories; Thermal Field Theory; Cosmology of Theories beyond the SM; Lattice Quantum Field Theory
• Online Access: http://link.springer.com/article/10.1007/JHEP06(2019)075

Abstract Making use of a dimensionally-reduced effective theory at high temperature, we perform a nonperturbative study of the electroweak phase transition in the Two Higgs Doublet model. We focus on two phenomenologically allowed points in the parameter space, carrying out dynamical lattice simulations to determine the equilibrium properties of the transition. We discuss the shortcomings of conventional perturbative approaches based on the resummed effective potential — regarding the insufficient handling of infrared resummation but also the need to account for corrections beyond 1-loop order in the presence of large scalar couplings — and demonstrate that greater accuracy can be achieved with perturbative methods within the effective theory. We find that in the presence of very large scalar couplings, strong phase transitions cannot be reliably studied with any of the methods.