Nick E. Mavromatos (London):
CPT in the Early Universe and the Observed Baryon Asymmetry
Abstract:
CPT invariance is a property of any
relativistic, local and unitary quantum field theory on flat spacetimes, due
to a mathematical theorem. However, in the early Universe the conditions for
the validity of the theorem may not all be valid. In the talk I will discuss
examples of curved EarlyUniverse geometries, which lead to apparent CPT
Violation of light (active) neutrinos and an induced difference between
neutrino/antineutrino populations (a sort of Leptogenesis). The latter can
then freeze out at certain conditions and be communicated to the Baryon sector
of the Universe, producing a baryon asymmetry of the observed order of magnitude,
under natural assumptions.
As explicit examples of such a
situation, where the preferential role of neutrinos is singled out, I give
early Universe geometries with violations of rotational invariance (and thus
Lorentz symmetry) or situations from brane theory, where a brane Universe
representing our world passes through a collection of spacetime defects in
the bulk, represented by appropriately compactified lowerdimensional branes
(effective ``Dparticles''). If such scenarios turn out to be realistic, then
the role of sterile neutrinos on inducing Baryon Asymmetry in the Universe may
be obviated.
download document (pdf, 16,41 MB)
