Footprints of leptoquarks: from $$ R_{K^{(*)}} $$ R K ( ∗ ) to $$ K \rightarrow \pi \nu \bar{\nu }$$ K → π ν ν ¯

K + → π + ν¯ν Beyond Leading Logs and Vtd ∗

The calculation of QCD corrections beyond the leading logarithmic approximation for the short-distance dominated rare decay K → πνν̄ is summarized. This analysis requires the complete O(αs) corrections to the top contribution to all orders in the top-quark mass and a two-loop renormalization group (RG) calculation for the charm contribution. The inclusion of these QCD corrections reduces conside...

Measurement of Rare Kaon Decay K + → π + ν¯ν

In the Standard Model (SM) the transition K to πνν is a Flavor Changing Neutral Current (FCNC) process in which the first order weak decay is forbidden by the GIM mechanism but is allowed, though highly suppressed, in second order due to the differing masses of the up, charm and top quarks in the mediating loops. Theoretically, this decay is sensitive to the CKM matrix element Vtd, which is one...

For Publisher’s use RARE KAON DECAY FROM E949 AT BNL: K + → π + ν¯ν

The understanding of flavor dynamics is of fundamental importance in elementary particle physics. The study of K and B decays plays a crucial role in this respect. In particular, the precise measurement of the rare kaon decays K → πνν and K L → πνν is regarded as a theoretical ideal for the understanding of CP violation in the Standard Model (SM). These modes provide a clean environment for ext...

New , high statistics measurement of the K + → π 0 e + ν ( K + e 3 ) branching ratio

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