Two-loop neutrino model with exotic leptons

Two-loop-induced neutrino masses: A model-independent perspective

Loop Effects of Exotic Leptons on Vector-Boson Pair Production at e+e− Colliders

We study quantum effects of exotic heavy leptons on the production of two vector bosons in e+e− annihilation. We present closed analytic expressions for vector-boson self-couplings and differential cross sections, within the framework of two favourable new-physics scenarios: (i) the fourth-generation Majorana-neutrino model and (ii) an E6-inspired model with sequential mirror isodoublets. We co...

Loop Effects of Exotic Leptons on Vector - Boson Pair Production at e + e − Colliders

We study quantum effects of exotic heavy leptons on the production of two vector bosons in e + e − annihilation. We present closed analytic expressions for vector-boson self-couplings and differential cross sections, within the framework of two favourable new-physics scenarios: (i) the fourth-generation Majorana-neutrino model and (ii) an E 6-inspired model with sequential mirror isodoublets. W...

Two-loop neutrino masses and the solar neutrino problem.

The addition of m singlet right-handed neutrinos to the Standard Model leads to radiatively generated mass corrections for the SU(2)L doublet neutrinos. For those neutrinos which are massless at the tree level after this addition, this implies a small mass generated at the two-loop level via W exchange. We calculate these mass corrections exactly by obtaining an analytic form for the general ca...

Testing exotic neutrino-neutrino interactions with AGN neutrinos

We propose a test for non-standard neutrino-neutrino interactions by using ultrahigh energy AGN neutrinos. Such interactions would influence the AGN neutrino flux due to collisions with cosmic background neutrinos. For typical AGN neutrinos we obtain an upper limit for the coupling constant g < 6.4 ·10−3 if the mediator is light and g/(MX/MeV) < 0.013 if the mediator is heavy. We compare our re...