16,134 research outputs found
Neutrino coupling to cosmological background: A review on gravitational Baryo/Leptogenesis
In this work we review the theories of origin of matter-antimatter asymmetry
in the Universe. The general conditions for achieving baryogenesis and
leptogenesis in a CPT conserving field theory have been laid down by Sakharov.
In this review we discuss scenarios where a background scalar or gravitational
field spontaneously breaks the CPT symmetry and splits the energy levels
between particles and anti-particles. Baryon or Lepton number violating
processes in proceeding at thermal equilibrium in such backgrounds gives rise
to Baryon or Lepton number asymmetry.Comment: 62 pages, no figures. Invited review to appear in IJMP
Leptogenesis from Spin-Gravity Coupling Following Inflation
The energy levels of the left and the right handed neutrinos is split in the
background of gravitational waves generated during inflation which in presence
of lepton number violating interactions gives rise to a net lepton asymmetry at
equilibrium. Lepton number violation is achieved by the same dimension five
operator which gives rise to neutrino masses after electro-weak symmetry
breaking. A net baryon asymmetry of the same magnitude can be generated from
this lepton asymmetry by electroweak sphaleron processes.Comment: Journal version (accepted for publication in Phys. Rev. Lett.
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