K-π Resonances and the µ Polarization inKµ 3

Two Photon Contribution to Polarization in K + → π + μ + μ − ⋆

Short distance physics involving virtual top and charm quarks contributes to μ+ (and μ) polarization in the decay K+ → π+μ+μ−. Measurement of the parity violating asymmetry (ΓR−ΓL)/(ΓR+ΓL), where ΓR and ΓL are the rates to produce right and left-handed μ+, may provide valuable information on the unitarity triangle. The parity violating asymmetry also gets a contribution from Feynman diagrams wi...

Observation of D^{0} Meson Decays to π^{+}π^{-}μ^{+}μ^{-} and K^{+}K^{-}μ^{+}μ^{-} Final States.

The first observation of the D^{0}→π^{+}π^{-}μ^{+}μ^{-} and D^{0}→K^{+}K^{-}μ^{+}μ^{-} decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8 TeV, and corresponding to 2  fb^{-1} of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay D^{0}→K^{-}π^{+}[μ^{+}μ^{-}]_{ρ^{0}/ω}, where the t...

Parity Violating Longitudinal Muon Polarization in K + → π + μ + μ − Beyond Leading Logarithms ∗

We generalize the existing analyses of the parity violating muon polarization asymmetry ∆LR in K + → πμμ beyond the leading logarithmic approximation. The inclusion of next–to–leading QCD corrections reduces the residual dependence on the renormalization scales, which is quite pronounced in the leading order. This leads to a considerably improved accuracy in the perturbative calculation of the ...

The Rare Decays K + → π + νν̄ and K L → μ + μ −

We analyze the branching ratio for the FCNC mode K → πνν̄ in the standard model with QCD effects taken into account consistently to next-to-leading order. This involves a two-loop renormalization group analysis for the charm contribution, presented in this paper, and the calculation of O(αs) corrections to all orders in mt/MW for the top-quark case that we have described elsewhere. The inclusion...

Search for T - Violation in K + → π 0 μ + ν and K + → μ