No Arabic abstract
Neutral kaons produced in correlated pairs at a phi-factory offer unique possibilities to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The analysis of the data collected by the KLOE experiment at DAFNE is still ongoing with the aim of improving previous results and limits on several parameters describing CPT violation and decoherence. Ancillary measurements like the regeneration cross section on the beam pipe materials are also in progress and will be very useful to reduce the systematic uncertainties. Prospects on improvements at the KLOE-2 experiment, aiming at an increase of the integrated luminosity of about a factor of ten with an upgraded detector, will be also discussed.
The phi-factory DAPHNE offers a possibility to select pure kaon beams, charged and neutral ones. In particular, neutral kaons from phi->KS KL are produced in pairs and the detection of a KS (KL) tags the presence of a KL (KS). This allows to perform precise measurements of kaon properties by means of KLOE detector. Another advantage of a phi-factory consists in fact that the neutral kaon pairs are produced in a pure quantum state (J^(PC) = 1^(--)), which allowsto investigate CP and CPT symmetries via quantum interference effects, as well as the basic principles of quantum mechanics.A review of the most recent results of the KLOE experiment at DAPHNE using pure kaon beams or via quantum interferometry is presented together with prospects for kaon physics at KLOE-2.
The KLOE Collaboration completed the full data taking on March 2006, acquiring 2.5 fb ^ -1 at the peak of the phi and other 240 pb ^ -1 off-peak. A new Collaboration is working on a new project, called KLOE-2, to refine and extend the KLOE physics program. We present here some preliminary and published results from the KLOE Collaboration on the pseudoscalar eta meson and the study of gamma gamma processes, that are among the main points of the KLOE-2 physics program.
Preliminary result on the charged kaon lifetime, obtained by the KLOE experiment operating at DA$Phi$NE, the Frascati $phi$-factory, is presented
Kaon physics can test new-physics effects in leptonic or semileptonic decays. A unitarity test of the first row of the CKM mixing matrix is obtained from the precision measurements of Kl3 widths for K{pm}, KL, and (unique to KLOE) KS. The KLOE measurement of RK = {Gamma}(Ke2)/{Gamma}(K{mu}2) with an accuracy at the % level, aims at finding evidence of deviations from the SM prediction induced by lepton-flavor violation new-physics effects.
All relevant inputs for the extraction of the CKM matrix element vus from kl, ks and kpm decays have been measured at KLOE. From a global fit using only KLOE results, but ks lifetime, a value of $|vus|fzero = 0.2157 pm 0.0006$ is obtained, where fzero is the form factor parametrizing the hadronic matrix element evaluated at zero momentum transfer. Comparison of the values of fVus for $K_{e3}$ and $K_{mu3}$ modes provides a test of lepton universality at 0.8% level of accuracy. The value $vus/vud=0.2323(15)$ has been obtained from the ratio $Gamma(Ktomu u)/Gamma(pitomu u)$ using KLOE measurement of $BR(kpm to mudue)$ and lattice calculation of the ratio of decay constants $f_K/f_{pi}$. These results, together with $vud = 0.97418(26)$, are compatible at 0.6$sigma$ level with CKM matrix unitarity. The universality of lepton and quark weak couplings can be tested and constraints on new physics extensions of the Standard Model can be set using these very precise measurements from kaon decays.