PT Journal
AU NA48/2 Collaboration (Batley, JRea
   Fiorini, L
TI First observation and study of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay
SO Physics Letters B
JI Phys. Lett. B
PY 2019
BP 552
EP 561
VL 788
DI 10.1016/j.physletb.2018.11.046
LA English
AB The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.
ER