Connecting Light Dirac Neutrinos to a Multi-component Dark Matter Scenario in Gauged $B-L$ Model

Understand

We propose a new gauged $B-L$ extension of the standard model where light neutrinos are of Dirac type, naturally acquiring sub-eV mass after electroweak symmetry breaking, without any additional global symmetries.

• This is realised by choosing a different $B-L$ charge for right handed neutrinos than the usual $-1$ so that the Dirac Yukawa coupling involves an additional neutrinophilic scalar doublet instead of the usual Higgs doublet.
• The model can be made anomaly free by considering four additional chiral fermions which give rise to two massive Dirac fermions by appropriate choice of singlet scalars.
• The choice of scalars not only helps in achieving the desired particle mass spectra via spontaneous symmetry breaking, but also leaves a remnant $Z_2 \times Z'_2$ symmetry to stabilise the two dark matter candidates.