A model of electroweak-scale right-handed neutrino mass
Abstract
If neutrino masses are realized through the see-saw mechanism, can the right-handed neutrinos be produced and detected at present and future colliders? The answer is negative in the most popular see-saw scenarios for the simple reason that they are too heavy in these models. However, a simple extension of the Standard Model (SM) particle content, including mirror fermions, two
SU(2
)
L
triplet and one singlet Higgs fields, leads to a scenario in which the see-saw mechanism is realized with the Majorana mass
M
R
of the right-handed neutrino being of the order of the electroweak scale or smaller. A custodial SU(2) symmetry arising from the two triplet Higgs fields ensures that
ρ=1
at tree level even when their vacuum expectation values (VEV) which determine the value of
M
R
, can be as large as the electroweak scale.
M
R
is found to obey the bound
M
Z
2
≤
M
R
<246GeV
which makes it accessible experimentally (Tevatron, LHC or ILC) since, in our scenario,
ν
R
's can couple directly to the Standard Model (SM) gauge bosons.