Neutral-meson oscillations with torsion

TL;DR

This paper suggests that spacetime torsion in Einstein-Cartan theory causes asymmetries in fermion masses at high densities, potentially explaining matter-antimatter imbalance through neutral-meson oscillations.

Contribution

It introduces a mechanism linking spacetime torsion to particle-antiparticle asymmetry via modified meson oscillations in the early Universe.

Findings

Fermions have higher effective masses than antifermions at high densities due to torsion.

Neutral-meson oscillations favor production of light quarks and heavy antiquarks.

This mechanism may contribute to baryogenesis in the early Universe.

Abstract

We propose a simple mechanism that may explain the observed particle-antiparticle asymmetry in the Universe. In the Einstein-Cartan-Sciama-Kibble theory of gravity, the intrinsic spin of matter generates spacetime torsion. Classical Dirac fields in the presence of torsion obey the nonlinear Hehl-Datta equation which is asymmetric under a charge-conjugation transformation. Accordingly, at extremely high densities that existed in the very early Universe, fermions have higher effective masses than antifermions. As a result, a meson composed of a light quark and a heavy antiquark has a lower effective mass than its antiparticle. Neutral-meson oscillations in thermal equilibrium therefore favor the production of light quarks and heavy antiquarks, which may be related to baryogenesis.