Test of Chiral Perturbation Theory in kaon decays

✍ Scribed by C. Lazzeroni

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 316 KB
• Volume: 187
• Category: Article
• ISSN: 0920-5632
• DOI: 10.1016/j.nuclphysbps.2009.01.014

✦ Synopsis

This paper presents results obtained by the CERN experiment NA48/2. Sample of 7146 K ± → π ± e + e - decays, of 1164 K ± → π ± γγ events and of 120 K ± → π ± γe + e -events have been collected with small background contamination. Branching ratio and form factors for three different models have been obtained for K ± → π ± e + e -, plus a model-independent branching ratio. In addition, the first measurement of the direct CP violating asymmetry has been performed. A measurement of the branching ratio has been obtained for K ± → π ± γγ, and kinematic distributions have been compared to ChPT expectations. Finally, the branching ratio of K ± → π ± γe + e -has been measured in the kinematically accessible region, representing the first observation of such a decay. * On behalf of the NA48 Collaboration.