M. Napolitano

Measurement of σ(e+e−→π+π−) from threshold to 0.85 GeV2 using initial state radiation with the KLOE detector

Measurement ofxa0σ(e+e−→π+π−)xa0from threshold to 0.85 GeV2xa0using initial state radiation with the KLOE detector

MEASUREMENTS OF THE ABSOLUTE BRANCHING RATIOS FOR THE DOMINANT K(L) DECAYS, THE K(L)LIFETIME, AND V(US) WITH THE KLOE DETECTOR.

From a sample of about 10 9 φ mesons produced at DA NE, we have selectedKL mesons tagged by observing KS → π+π− decays. We present results on the major KL branching ratios, including those of the semileptonic decays needed for the determina |Vus |. These branching ratio measurements are fully inclusive with respect to final-state radiation. The KL lif time has also been mea sured. uf6d9 2005 Published by Elsevier B.V. 0370-2693/

First observation of quantum interference in the process Phi-->K(S) K(L) --> pi+ pi- pi+ pi-: A test of quantum mechanics and CPT symmetry

– see front matter uf6d9 2005 Published by Elsevier B.V. doi:10.1016/j.physletb.2005.10.018 44 KLOE Collaboration / Physics Letters B 632 (2006) 43–50

Measurement of the form-factor slopes for the decay K(L)-->pi+-e-+nuwith the KLOE detector

We present the first observation of quantum interference in the process phi ->KS KL ->pi+pi-pi+pi-. This analysis is based on data collected with the KLOE detector at the e^+e^- collider DAFNE in 2001--2002 for an integrated luminosity of about 380pb^-1. Fits to the distribution of Delta t, the difference between the two kaon decay times, allow tests of the validity of quantum mechanics and CPT symmetry. No deviations from the expectations of quantum mechanics and CPT symmetry have been observed. New or improved limits on various decoherence and CPT violation parameters have been obtained

Measurement of the absolute branching ratio for the K+->mu (+) v(gamma) decay with the KLOE detector

Abstract We present a measurement of the K–π vector current form-factor parameters for the decay K L → π ± e ∓ ν . We use 328 pb−1 of data collected in 2001 and 2002, corresponding to ∼2 million K e 3 events. Measurements of semileptonic form factors provide information about the dynamics of the strong interaction and are necessary for evaluation of the phase-space integral I K e needed to measure the CKM matrix element | V u s | for K L → π ± e ∓ ν decays. Our result is λ + = ( 28.6 ± 0.5 ± 0.4 ) × 10 −3 for a linear fit, and λ + ′ = ( 25.5 ± 1.5 ± 1.0 ) × 10 −3 , λ + ″ = ( 1.4 ± 0.7 ± 0.4 ) × 10 −3 for a quadratic fit.

Measurement of the branching ratio of the K-L ->pi(+) pi(-) decay with the KLOE detector

Abstract We have measured the fully inclusive K + → μ + ν ( γ ) absolute branching ratio with the KLOE experiment at DAΦNE, the Frascati ϕ -factory. From some 865u2009283 K + → μ + ν ( γ ) decays obtained from a sample of ∼ 5.2 × 10 8 , ϕ -meson decays, we find BR ( K + → μ + ν μ ( γ ) ) = 0.6366 ± 0.0009 stat . ± 0.0015 syst . , corresponding to an overall fractional error of 0.27%. Using recent lattice results on the decay constants of pseudoscalar mesons one can obtain an estimate for the CKM mixing matrix element | V u s | = 0.2223 ± 0.0026 .We have measured the fully inclusive K+ ->mu+nu(gamma) absolute branching ratio with the KLOE experiment at DAFNE, the Frascati Phi-factory. From some 865,283 K+ ->mu+nu(gamma) decays obtained from a sample of about 5.2x10^8 Phi-meson decays, we find BR(K+ ->mu+ nu (gamma)) = 0.6366 +-0.0009(stat.) +-0.0015(syst.), corresponding to an overall fractional error of 0.27%. Using recent lattice results on the decay constants of pseudoscalar mesons one can obtain an estimate for the CKM mixing matrix element |Vus|=0.2223+-0.0026.

STUDY OF THE DECAY PHI --->F(0)(980) GAMMA ---> PI+ PI- GAMMA WITH THE KLOE DETECTOR.

We present a measurement of the branching ratio of the CP violating decay KL->pi+pi- performed by the KLOE experiment at the phi factory DAFNE. We use 328 pb-1 of data collected in 2001 and 2002, corresponding to ~ 150 million tagged KL mesons. We find BR(KL->pi+pi-) =

Study of the a(0)(980) meson via the radiative decay phi -> eta pi(0)gamma with the KLOE detector

(1.963 +/- 0.012 +/- 0.017)x 10^-3. This branching ratio measurement is fully inclusive of final-state radiation. Using the above result, we determine the modulus of the amplitude ratio |eta_{+-}| to be (2.219 +/- 0.013)x 10^{-3} and |epsilon| to be (2.216 +/- 0.013)x 10^{-3}.

Proposal to Measure the Rare Decay

We measured, with the KLOE detector, the spectrum of pi+pi- invariant mass in a sample of 6.7 x 10^5 e+e- -->pi+pi-g events with the photon at large polar angle (theta_g>45^o) at a centre of mass energy sqrt(s) around the phi mass. We observe a clear contribution from the intermediate process phi -->f0(980)g. A sizeable effect is also observed in the distribution of the forward-backeard asymmetry. We use different theoretical models to fit the spectrum and we determine the f_0 mass and coupling constants to the phi, to pi+pi- and to KK.

K^{+} \rightarrow \pi^{+} \nu \bar{\nu}

We have studied the ϕ→a0(980)γϕ→a0(980)γ process with the KLOE detector at the Frascati ϕ xa0-factory DAΦNE by detecting the ϕ→ηπ0γϕ→ηπ0γ decays in the final states with η→γγη→γγ and η→π+π−π0η→π+π−π0. We have measured the branching ratios for both final states: Br(ϕ→ηπ0γ)=(7.01±0.10±0.20)×10−5Br(ϕ→ηπ0γ)=(7.01±0.10±0.20)×10−5 and (7.12±0.13±0.22)×10−5(7.12±0.13±0.22)×10−5, respectively. We have also extracted the a0(980)a0(980) mass and its couplings to ηπ0ηπ0, K+K−K+K−, and to the ϕ meson from the fit of the ηπ0ηπ0 invariant mass distributions using different phenomenological models.