Spinors with torsion and matter$-$antimatter asymmetry

Fuente: arXiv
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Main Author: Popławski, Nikodem
Format: Preprint
Published: 2021
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author Popławski, Nikodem
author_facet Popławski, Nikodem
contents The conservation law for the orbital plus spin angular momentum of a free Dirac particle in curved spacetime requires that the affine connection has the antisymmetric part: the torsion tensor, which extends general relativity to the Einstein$-$Cartan theory of gravity. In the presence of torsion, the Dirac equation becomes a nonlinear, cubic equation in the spinor wave function. We show that the energy eigenvalues of the corresponding Hamiltonian as functions of the momentum are different for the fermion and antifermion components of the spinor, violating charge conjugation symmetry, and also depend on the helicity. Consequently, particles of matter and antimatter have different dispersion relations and therefore different masses. This mass difference increases with density and becomes significant near the Cartan density, which existed in the early Universe. Because antimatter particles were more massive than matter particles, they were also slower during pair production in the early Universe and therefore had higher cross sections for gravitational capture by primordial black holes. This difference might have led to the matter$-$antimatter imbalance in the observable Universe: the missing antimatter fell into black holes.
format Preprint
id arxiv_https___arxiv_org_abs_2101_04212
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Spinors with torsion and matter$-$antimatter asymmetry
Popławski, Nikodem
General Relativity and Quantum Cosmology
Quantum Physics
The conservation law for the orbital plus spin angular momentum of a free Dirac particle in curved spacetime requires that the affine connection has the antisymmetric part: the torsion tensor, which extends general relativity to the Einstein$-$Cartan theory of gravity. In the presence of torsion, the Dirac equation becomes a nonlinear, cubic equation in the spinor wave function. We show that the energy eigenvalues of the corresponding Hamiltonian as functions of the momentum are different for the fermion and antifermion components of the spinor, violating charge conjugation symmetry, and also depend on the helicity. Consequently, particles of matter and antimatter have different dispersion relations and therefore different masses. This mass difference increases with density and becomes significant near the Cartan density, which existed in the early Universe. Because antimatter particles were more massive than matter particles, they were also slower during pair production in the early Universe and therefore had higher cross sections for gravitational capture by primordial black holes. This difference might have led to the matter$-$antimatter imbalance in the observable Universe: the missing antimatter fell into black holes.
title Spinors with torsion and matter$-$antimatter asymmetry
topic General Relativity and Quantum Cosmology
Quantum Physics
url https://arxiv.org/abs/2101.04212