  Photon-neutrino interactions arise quite naturally in noncommutative field
theories. Such couplings are absent in ordinary field theory and imply
experimental lower bounds on the energy scale Lambda_NC ~ 1/|theta|^2 of
noncommutativity. Using non-perturbative methods and a Seiberg-Witten map based
covariant approach to noncommutative gauge theory, we obtain theta-exact
expressions for the interactions, thereby eliminating previous restrictions to
low-energy phenomena. We discuss implications for plasmon decay, neutrino
charge radii, big bang nucleosynthesis and ultrahigh energy cosmic rays. Our
results behave reasonably throughout all interaction energy scales, thus
facilitating further phenomenological applications.
