Editing Georgi–Glashow model (section)

===Neutrino masses===

As the SM the original Georgi–Glashow model proposed in<ref name=GG /> does not include neutrino masses. However, since [[neutrino oscillation]] has been observed such masses are required. The solutions to this problem follow the same ideas which have been applied to the SM: One on hand on can include a <math>SU(5)</math> singulet which then can generate either Dirac masses or Majorana masses. As in the SM one can also implement the [[Seesaw mechanism|type-I seesaw mechanism]] which then generates naturally light masses.

On the other hand, one can just parametrize the ignorance about neutrinos using the dimension 5 Weinberg operator:
:<math>\mathcal{O}_{W}=(\overline{\mathbf{5}}_F \mathbf{5}_H)\frac{Y_\nu}{\Lambda}(\overline{\mathbf{5}}_F \mathbf{5}_H)+h.c.
</math>
with <math> Y_\nu</math> the <math> 3\times 3</math> [[Yukawa interaction|Yukawa matrix]] required for the mixing between flavours.