Prof. Mikhail Shaposhnikov

Neutrino Minimal Standard Model

by Mikhail Shaposhnikov

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The Neutrino Minimal Standar Model (nuMSM or MSM) is an extension of the Standard Model with three right-handed (or sterile) neutrinos. It aims to address within one consistent framework several problems beyond the Standard Model The Lagrangian of the MSM is
Here are new Yukawa couplings, are left-handed leptonic doublets, the index labels generations, is a Higgs doublet with . The right-handed neutrinos have zero electric, weak and strong charges. The Majorana masses are consistent with the gauge symmetries of the SM This is the see-saw Lagrangian, however the Majorana masses of the right-handed neutrinos are chosen to be below electroweak scale. The smallness of the neutrino masses is achieved via small Yukawa couplings.
See references [1, 2] for the original paper and [3] for the recent review
References:
  • [1]^ T. Asaka and M. Shaposhnikov The nuMSM, dark matter and baryon asymmetry of the universe, Phys. Lett. B620:17-26 (2005) INSPIRE
  • [2]^ T. Asaka, S. Blanchet and M. Shaposhnikov The nuMSM, dark matter and neutrino masses, Phys. Lett. B631:151-156 (2005) INSPIRE
  • [3]^ A. Boyarsky, O. Ruchayskiy and M. Shaposhnikov, Ann. Rev. Nucl. Part. Sci. 59 (2009) 191 [arXiv:0901.0011]. INSPIRE