Exploring strange origin of Dirac neutrino masses at hadron colliders

Abstract

We consider the possibility that Dirac neutrino masses may be a manifestation of chiral symmetry breaking via nonperturbative QCD dynamics. The key role played by light quarks in this mechanism can naturally lead to signals that are accessible to hadron colliders. Bounds from charged meson decays imply a dominant effect from the strange quark condensate. We propose a model for Dirac neutrino mass generation with an extra Higgs doublet at the TeV scale and significant coupling to strange quarks and leptons. Current data on $D\ensuremath{-}\overline{D}$ mixing constrain the allowed parameter space of the model, and a 100 TeV $pp$ collider would either discover or largely exclude it. A distinct feature of this scenario is that measurements of the charged Higgs leptonic branching ratios can distinguish between ``normal'' and ``inverted'' neutrino mass hierarchies, complementing future determinations at neutrino oscillation experiments.