Light Neutrinos from a Mini-Seesaw Mechanism in Warped Space

Understand

The seesaw mechanism provides a simple explanation for the lightness of the known neutrinos.

• Under the standard assumption of a weak scale Dirac mass and a heavy sterile Majorana scale the neutrino mass is naturally suppressed below the weak scale.
• However, Nature may employ Dirac and Majorana scales that are much less than typically assumed, possibly even far below the weak scale.
• In this case the seesaw mechanism alone would not completely explain the lightness of the neutrinos.