The last BNL measurement of the K + → π + νν̄ 1 Branching Ratio

New results for K+→π+νν at low π+ momentum from BNL E949

The BNL E949 experiment was a successor to BNL E787 and was aimed to measure the branching ratio of the K+ → π+νν̄ decay. After detector upgrades were made, data equivalent to 1.7 × 1012 K+ decays at rest were collected in a 2002 physics run. The data were analyzed via a blind analysis with a technique called the “Bifurcation Method”. In this report we present the results of a search for K+ → π+...

New measurement of the K + → π + νν̄ 1 branching ratio

Bayesian estimate of the effect of BB̄ mixing measurements on the CKM matrix elements

A method employing Bayesian statistics is used to incorporate recent experimental results on B0dB̄ 0 d and B 0 s B̄ 0 s mixing into a measurement of the Cabibbo-Kobayashi-Maskawa matrix elements with small theoretical uncertainties. The neutral B meson mixing results yield a slight improvement in the estimate of |Vtd|. Prospects for improving the knowledge of the CKM matrix elements with measurem...

Search of New Physics with Kaon decays at NA 62

the current short term phase (data taking completed in years 2007-8) we are studying the ratio RK = Γ(K→eνe(γ)) Γ(K→μνμ (γ)) of leptonic decay rates, which provides a golden probe for testing the structure of the weak interactions. In the second phase (long term) we will then focus on the measurement of the branching ratio of the very rare kaon decay K+ → π+νν̄ aiming at collecting O(100) K+→ π+...

Measurement of B ( K + → π + νν ) 1

The experimental measurement of K→πνν is reviewed. New results from experiment E787 at BNL are presented: with data from 1995–97 the branching ratio has been measured to be B(K→πνν ) = (1.5 −1.2) × 10 . The future prospects for additional data in this mode are examined.