Accessing directly the properties of fundamental scalars in the confinement and Higgs phase

TL;DR

This study compares the propagators of gauge bosons, scalars, and ghosts in SU(2) gauge theory with fundamental scalars across confinement and Higgs phases using lattice gauge theory, revealing similar behaviors except for the ghost propagator.

Contribution

It provides a detailed lattice gauge theory analysis of propagators in both phases, highlighting the gauge-dependent properties and potential effects of Gribov copies.

Findings

Gauge boson acquires a screening mass in both phases

Scalar screening mass exceeds the renormalized mass

Ghost propagator shows significant phase-dependent variation

Abstract

The properties of elementary particles are encoded in their respective propagators and interaction vertices. For a SU(2) gauge theory coupled to a doublet of fundamental complex scalars these propagators are determined in both the Higgs phase and the confinement phase and compared to the Yang-Mills case, using lattice gauge theory. Since the propagators are gauge-dependent, this is done in the Landau limit of 't Hooft gauge, permitting to also determine the ghost propagator. It is found that neither the gauge boson nor the scalar differ qualitatively in the different cases. In particular, the gauge boson acquires a screening mass, and the scalar's screening mass is larger than the renormalized mass. Only the ghost propagator shows a significant change. Furthermore, indications are found that the consequences of the residual non-perturbative gauge freedom due to Gribov copies could be different in the confinement and the Higgs phase.