Jul 16 – 22, 2009
Kraków, Poland
Europe/Warsaw timezone

Vus and lepton universality from kaon decays at KLOE

Jul 17, 2009, 3:45 PM
Large (Kraków, Poland)


Kraków, Poland

The Auditorium Maximum of the Jagiellonian University 33 Krupnicza Street 31-123 Kraków
Flavour Physics II. Flavour Physics


Dr Erika De Lucia (Laboratori Nazionali di Frascati - INFN)


KLOE has measured most decay branching ratios of K_S, K_L amd K^+- mesons. It has also measured the K_L and the K^+- lifetime and determined the shape of the form factors involved in kaon semileptonic decays. We present a description of the above measurements and a well organized compendium of all of our data, with particular attention to correlations. These data provide the basis for the determination of the CKM parameter V_us and a test of the unitary of the quark flavor mixing matrix. We also test the lepton universality in Kl3 decays and place bounds on new physics using measurements of V_us from Kl2 and Kl3 decays. All of the above measurements, together with the results on KS, KL and K+- decays published during 2006 and 2007 have recently combined in JHEP 04 (2008) 059, to obtain the KLOE determination of Vus. A measurement of the ratio R_K=Gamma(Ke2)/Gamma(Kmu2) with 1.3% accuracy has also been performed. The result is based on 2.2 fb-1 of data collected at the Frascati e+e- collider DAFNE. Recently, it has been pointed out that in a supersymmetric framework, lepton flavor changing processes mediated by the charged Higgs could occur, in particular in the kaon decay to an electron and tau neutrino. In this scenario, deviations of up to few percent on R_K from SM expectation are quite possible. The measurement will be described, and its theoretical implications will be discussed.

Primary author

Dr Erika De Lucia (Laboratori Nazionali di Frascati - INFN)

Presentation materials