RK and RK* beyond the standard model

Measurements of the ratio of B -> K*mu mu to B -> K*ee branching fractions, R-K*, by the LHCb Collaboration strengthen the hints from previous studies with pseudoscalar kaons, R-K, for the breakdown of lepton universality, and therefore the Standard Model (SM), to similar to 3.5 sigma. Complementarity between RK and R-K* allows us to pin down the Dirac structure of the new contributions to be predominantly SM-like chiral, with possible admixture of chirality-flipped contributions of up to O(few10% ). Scalar and vector leptoquark representations (S-3, V-1,V-3) plus possible ((S) over bar (2),V-2) admixture can explain R-K,R-K* via tree-level exchange. Flavor models naturally predict leptoquark masses not exceeding a few TeV, with couplings to third-generation quarks at O(0.1), implying that this scenario can be directly tested at the LHC.