PoS - Proceedings of Science
Volume 352 - XXVII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2019) - Working Group 4: Hadronic and Electroweak Oberservables
Recent results on Kaon decays from NA48/2
A. Bizzeti*  on behalf of the NA48/2 Collaboration
Full text: pdf
Pre-published on: June 27, 2019
Published on: October 04, 2019
Abstract
The first observation of the K± → π± π0 e+ e- rare decay by the NA48/2 experiment at CERN SPS is reported, based on ∼ 2x10^11 K± decays recorded in 2003-2004. From a sample of 4919 candidates with 4.9% background the branching ratio in the full kinematic region is measured to be BR(K± → π± π0 e+ e-) = (4.24±0.14)x10^-6 .
The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on Chiral Perturbation Theory. The CP-violating asymmetry between K+ → π+ π0 e+ e- and K- → π- π0 e+ e- decay rates has been measured, providing an upper limit | A_CP | < 4.82 x 10^-2 at 90% CL.
The NA48/2 combined measurement of the charged kaon semileptonic form factors, based on 4.4 million K± → π0 e± ν_e and 2.3 million K± → π0 μ± ν_μ events collected in 2004, is presented. This result represents the most precise form factor measurement from a combined Kl3 analysis.
DOI: https://doi.org/10.22323/1.352.0116
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.