Speaker
Flavio Archilli
(University of Rome Tor Vergata)
Description
A phi-factory offers the possibility to select pure kaon beams: neutral kaons from phi → KS KL are in fact produced in pairs and the detection of a KS (KL) tags the presence of a KL (KS), the same holds for charged kaons. This allows to perform precise measurement of kaon properties. The KLOE experiment has measured most decay branching ratios of K_S, K_L and K^+- mesons. It has also measured the KL and the K^+- lifetime and determined the shape of the form factors involved in kaon semileptonic decays. These data provide the basis for the determination of the CKM parameter Vus and the most precise test of the unitary of the quark flavor mixing matrix. We are presently finalizing new determinations of the KL and KS lifetimes using the whole KLOE data set, consisting of more than 109 phi -> KS KL decays. The KL lifetime, which has been already measured by KLOE with 0.6% accuracy using 20% of the total data sample (PLB 626, 2005, 15), will be extracted from the proper time distribution of KL->3pi0 decays, tagged by a KS->pi+pi- decay on the opposite hemisphere of the apparatus. A competitive measurement of the KS lifetime is obtained from the proper time distribution of KS->pi+pi- decays. Bounds on new physics extensions of the standard model with lepton flavor violation can be set using the KLOE result on RK = Gamma(Ke2)/Gamma(Kmu2) based on the complete data set of 2.2 fb-1 collected at the Frascati e+e- collider DAFNE. The final 1.3% accuracy on the ratio RK has been achieved measuring the differential width dGamma(K -> e nu gamma)/dE_{gamma}/Gamma(K -> mu nu) for photon energies 10<E_{gamma}<250 MeV. KLOE recent results will be presented together with an outlook for further improvements in the near future.
Primary author
Collaboration KLOE
(Laboratori Nazionali di Frascati - INFN)
