Neutrino physics with dark matter experiments and the signature of new baryonic neutral currents

New neutrino states ν_b, sterile under the standard model interactions, can be coupled to baryons via the isoscalar vector currents that are much stronger than the standard model weak interactions. If some fraction of solar neutrinos oscillate into ν_b on their way to Earth, the coherently enhanced elastic ν_b-nucleus scattering can generate a strong signal in the dark matter detectors. For the interaction strength a few hundred times stronger than the weak force, the elastic ν_b-nucleus scattering via new baryonic currents may account for the existing anomalies in the direct detection dark matter experiments at low recoil. We point out that for solar-neutrino energies, the baryon-current-induced inelastic scattering is suppressed, so that the possible enhancement of a new force is not in conflict with signals at dedicated neutrino detectors. We check this explicitly by calculating the ν_b-induced deuteron breakup, and the excitation of a 4.4MeV γ line in C12. A stronger-than-weak force coupled to the baryonic current implies the existence of a new Abelian gauge group U(1) _B with a relatively light gauge boson.