Observing Dirac neutrinos in the cosmic microwave background

  title={Observing Dirac neutrinos in the cosmic microwave background},
  author={Kevork N. Abazajian and Julian Heeck},
  journal={Physical Review D},
Planned CMB Stage IV experiments have the potential to measure the effective number of relativistic degrees of freedom in the early Universe, $N_\text{eff}$, with percent-level accuracy. This probes new thermalized light particles and also constrains possible new-physics interactions of Dirac neutrinos. Many Dirac-neutrino models that aim to address the Dirac stability, the smallness of neutrino masses or the matter--anti-matter asymmetry of our Universe endow the right-handed chirality… 

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