Effective Theory and Simple Completions for Neutrino Interactions

We consider all the dimension 6 operators as well as some simple extensions of the standard model that give new contributions to neutrino interactions with matter. Such interactions are usually parametrized by αβ , where α and β are neutrino flavor indices taking the values e, μ and τ . In the simple models we consider the αβ ’s are much more constrained than in the operatorbased model-independent approach. Typically the αβ ’s are restricted to be smaller in magnitude than around 10−3. In some of the leptoquark models, a specific pattern for the leptoquark Yukawa couplings allows the diagonal element ττ to be as large as ∼ 0.1, or one of ee, μμ ∼ 0.01. We discuss the interplay between neutrino physics and leptoquark searches at the LHC.