Physical Review Letters
Neutrino-induced charged-current coherent kaon production nu(mu)A -> mu(-)K(+)A is a rare, inelastic electroweak process that brings a K+ on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than the neutrino-induced charged-current coherent pion production because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state K+, mu(-), and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at 3 sigma significance.
Wang, Z., Marshall, C. M., Aliaga, L., Altinok, O., Bellantoni, L., Bercellie, A., ... & Cai, T. (2016). Evidence of Coherent K+ Meson Production in Neutrino-Nucleus Scattering. Physical review letters, 117(6), 061802.