Abstract
Abstract The NA48/2 collaboration has analysed more than one million K ± → π + π − e ± ν decays, resulting in the improved determination of branching fraction by a factor of 3 and high precision form factor measurements. Concurrently, about 45000 K ± → π 0 π 0 e ± ν decays have been analyzed. Background contamination below the percent level and very good π 0 reconstruction allow the first accurate measurement of the branching fraction and decay form factor at the percent level. The achieved precision makes possible the observation of small effects such as π + π − → π 0 π 0 re-scattering. Both K e 4 modes decay properties bring new precise inputs to Low Energy QCD studies and can provide strong tests of ChPT predictions. Future prospects include the observation of several thousand decays in similar muonic modes K ± → π 0 π 0 μ ± ν and K ± → π + π − μ ± ν , that could be studied also in the forthcoming NA62 experiment.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call