Torsion: theory and possible observables

TL;DR

This paper explores the theoretical foundations and potential experimental signatures of torsion fields in physics, examining their interactions with matter, implications for quantum field theory, and challenges in integrating torsion into the Standard Model.

Contribution

It provides a detailed theoretical analysis of torsion's role in quantum field theory, its possible observables, and the difficulties of embedding torsion into the Standard Model framework.

Findings

Torsion interacts nonminimally with spinor and scalar fields.

Effective torsion action is constrained by symmetry and coupling constants.

Embedding torsion into the Standard Model faces consistency issues.

Abstract

We discuss the theoretical basis for the search of the possible experimental manifestations of the torsion field at low energies. First, the quantum field theory in an external gravitational field with torsion is reviewed. The renormalizability requires the nonminimal interaction of torsion with spinor and scalar (Higgs) fields. The Pauli-like equation contains new torsion-dependent terms which have a different structure as compared with the standard electromagnetic ones. The same concerns the nonrelativistic equations for spin-${1}/{2}$ particle in an external torsion and electromagnetic fields. Second, we discuss the propagating torsion. For the Dirac spinor coupled to the electromagnetic and torsion field there is some additional softly broken local symmetry associated with torsion. As a consequence of this symmetry, in the framework of effective field theory, the torsion action is fixed with accuracy to the values of the coupling constant of the torsion-spinor interaction, mass of the torsion and higher derivative terms. The introduction of the Higgs field spoils the consistency of this scheme, and the effective quantum field theory for torsion embedded into the Standard Model is not possible. The phenomenological consequences of the torsion-fermion interaction are drown and the case of the torsion mass of the Planck order is discussed.