Aleksander Gajos (Jagiellonian University Cracow)
The KLOE experiment at the DAΦNE φ-factory of the INFN Frascati Laboratory collected data corresponding to 2.5 fb^−1 of integrated luminosity. Neutral kaon pairs produced in φ-meson decays offer unique possibilities to perform tests of fundamental discrete symmetries. The entanglement of the two kaons is exploited to search for possible violation of CPT symmetry and Lorentz invariance in the context of the Standard-Model Extension (SME) framework. A new approach to the analysis of φ -> K_S K_L -> π+ π-, π+ π- events has been adopted allowing us to independently measure all four CPT violating parameters Δ a_μ appearing for neutral kaons in the SME. The final KLOE results on Δ a_μ will be presented. These are presently the most precise measurements in the quark sector of the SME. We also shortly discuss the perspectives for a new measurement using the KLOE-2 apparatus equipped with a new inner tracker. The measurement of the absolute BR of of the K+ -> 3π(γ) decay completes the KLOE program of precise and fully inclusive kaon dominant BR's measurements. The most recent result, BR(K± -> π± π+ π-) = (5.56 ± 0.20) % (Chiang et al.), dates back to more than 30 years ago. We use as normalization sample the tags given by K -> μν and K -> ππ0 decays. The track of the tagging kaon is backward extrapolated to the interaction point, then the kinematics of the decay φ -> K+ K-, gives us the possibility to define the path of the signal kaon (direction and momentum). The decay products of the kaons have a very low momentum, less than 200 MeV/c, and curl up in the KLOE magnetic field (0.52 T). To optimize the quality of the track reconstruction we select kaons decaying before the Drift Chamber Inner Wall (inner radius(DC) = 25 cm), so that only their decay products cross the DC (three tracks instead of four). We require at least two reconstructed tracks (pion candidates) and we count the number of K -> 3π(γ) decays from the missing mass spectrum. The final KLOE result on the BR(K+ -> π+ π- π+ (γ)) will be presented.
Prof. Antonio Di Domenico (Dept. of Physics, Sapienza University of Rome & INFN Rome, Italy)