Quantum mechanics

Theoretical physics

Supersymmetry

Gravitation

Lepton

Nuclear physics

Leptogenesis

Particle physics

Astrophysics

Neutrino

Classical mechanics

Grand Unified Theory

Physics

MAJORANA

Astronomy

Seesaw molecular geometry

Gravitational wave

Seesaw mechanism

Electron

Physical Review Letters

We present the possibility that the seesaw mechanism with thermal leptogenesis can be tested using the stochastic gravitational background. Achieving neutrino masses consistent with atmospheric and solar neutrino data, while avoiding nonperturbative couplings, requires right handed neutrinos lighter than the typical scale of grand unification. This scale separation suggests a symmetry protecting the right-handed neutrinos from getting a mass. Thermal leptogenesis would then require that such a symmetry be broken below the reheating temperature. We enumerate all such possible symmetries consistent with these minimal assumptions and their corresponding defects, finding that in many cases, gravitational waves from the network of cosmic strings should be detectable. Estimating the predicted gravitational wave background, we find that future space-borne missions could probe the entire range relevant for thermal leptogenesis.

Testing the Seesaw Mechanism and Leptogenesis with Gravitational Waves