46 research outputs found
KLOE measurement of the charged kaon absolute semileptonic BR's
This paper is devoted to the measurement of the fully inclusive absolute
branching ratios of the charged kaon semileptonic decays,
and . The
measurements have been done using a tag technique, employing the two-body
decays, and , and using a sample
of about 410 pb collected during the 2001 and 2002 data taking of the
KLOE experiment at Daphne, the Frascati -factory. The results obtained
are BR(K) = and BR(K)
= .Comment: Contributed paper to Lepton Photon 2007, Daegu, Korea, 13-18 August
2007, 5 pages, 2 figure
Recent Results from the KLOE Experiment at DAPHNE
Recent results from the KLOE experiment at the DAPHNE e+e- collider are
presented. KLOE has collected about 500 pb^-1 of data in the years from 2000 to
2002. Preliminary results are obtained using wide samples of the full
statistics and include: the BR of the Ke3 decay of the K_S and the first
measurement of its charge asymmetry, the ratio
BR(K_S-->pi+pi-(gamma))/BR(K_S-->pi^0pi^0), the ratio
BR(K_L-->gammagamma)/BR(K_L-->3pi^0), a detailed study of the decay
phi-->pi+pi-pi^0, the ratio BR(phi-->eta' gamma)/BR(phi-->eta gamma) and the
pseudoscalar mixing angle phi_P, the phi-->f_0 gamma and the phi-->a_0 gamma
BR's.Comment: 9 pages, 5 figures. To be published in the Proceedings of the
XXXVIIIth Rencontres de Moriond - Electroweak Interactions and Unified
Theorie
Studies of K0S decays with the KLOE detector at DAFNE
The KLOE detector at DAFNE has collected about 30 pb-1 by the end of year
2000,' allowing, among other things, accurate measurements on several decay
channels of the K0S meson.
With data acquired in the year 2000 run we have measured the ratio of the
branching ratios of the K0S to two charged and neutral pions to 1.5 percent
accuracy.
The branching ratio of the semileptonic decay of the K0S is also measured to
5 percent accuracy, the best measurement of this BR to date.Comment: Contributed Paper to LP0
KLOE extraction of in the mass range [0.35,0.95] GeV^2
The KLOE Experiment at the factory DANE, has measured the cross
section using two different selection
schemes: requiring the photon emission at small polar angle and detecting the
photon at large polar angle in the calorimeter. Using a theoretical radiator
function we extract the pion form factor and obtain the contribution
to the anomalous magnetic moment of the muon. Results presented here come from
the analysis of 240 pb^{-1} collected in 2002, with improved systematic
uncertainty with respect to the published KLOE analysis. We also include an
update of the previous analysis.Comment: Contributed paper to Lepton Photon 200
Measuring the Hadronic Cross Section at KLOE using the Radiative Return
We present a study of the reaction e+e- \to pi+pi-gamma at the phi peak with
the KLOE detector at the phi-factory DAPHNE. This reaction allows us to obtain
the cross section for \e+e- \to pi+pi- from the e+e- center-of-mass energy W =
m_\phi = 1019 MeV down to threshold, i.e. 2m_pi < M_(pipi) < m_phi. This is
called radiative return. The status of the analysis and preliminary results on
the invariant mass spectrum of the two-pion-state are presented.Comment: Contributed Paper to "Lepton Photon 2001" Conference, Rome, July
23-28 2001; 7 pages, 5 plot
First results from phi -> KL KS decays with the KLOE detector
The KLOE experiment has collected 2.4 1/pb of integrated luminosity during
the commissioning of the DAFNE phi-factory in 1999. The performance of the
detector has been studied using phi -> KL KS decays collected during this
period, yielding also first measurements of relevant K parameters such as
masses and lifetimes. A clean Kshort -> pi+ pi- sample is used to select Klong
-> 2pi CP-violating decays and Klong -> Kshort regeneration events in the
detector material. Results on the regeneration probability in
beryllium-alluminum alloy and carbon-fiber plus aluminum composite are
presented.Comment: 21 pages, 20 figures, Contributed paper number 294 to XXX ICHEP,
Osaka July 200
and Decays from Kloe
Recent results obtained by the KLOE experiment operating at DANE, the
Frascati -factory, are presented. They mainly concern neutral kaon decays
including the dominant branching ratios, the lifetime and the
extraction of the parameter from the semileptonic decays
and lifetime. The best world upper limit on K_S \to \pppo channel is also
presentedComment: 9 pages, 6 figures. Proceedings of the Moriond EW Conference 200
Preliminary measurement of Gamma(Ke2)/Gamma(Km2) at KLOE
A preliminary measurement of RK = Gamma(Ke2)/Gamma(Km2) at the KLOE
experiment is discussed. The result, RK = (2.55+-0.05+-0.05)x 10^-5, is based
on 1.7 fb^-1 of luminosity integrated on the phi-meson peak at the Frascati
e^+e^- collider DAFNE, corresponding to ~8000 observed Ke2 events. Perspectives
on the methods planned to improve both the statistical and the systematic
errors are briefly outlined.Comment: 11 pages, 5 figures. Contributed paper for the XXIII International
Symposium on Lepton and Photon Interactions at High Energy, Lepton-Photon
2007, Aug 13-18 Daegu, Kore
Study of the radiative decay phi to a0(980) gamma with the KLOE detector
A sample of 1.25x10^9 phi decays, collected with the KLOE detector at the
Frascati phi-factory DAFNE at center of mass energy ~ Mphi, has been used to
study the radiative decay phi to eta pi0 gamma. This decay is dominated by phi
to a0(980) gamma. Two decay chains, corresponding to eta to gamma gamma and eta
to pi+ pi- pi0, have been selected. We found respectively: Br(phi to eta pi0
gamma)=(6.92 +/- 0.10 (stat.) +/- 0.20 (syst.))x10^(-5) and (7.19 +/- 0.17
(stat.) +/- 0.24 (syst.))x 10 ^(-5). The eta pi0 invariant mass distributions
have been fitted to obtain the relevant a0(980) parameters.Comment: 9 pages, 7 figures, Contributed paper to Lepton Photon 200
Measurement of Gamma(Ks -> pi+pi-gamma)/Gamma(Ks -> pi0pi0)
We have measured the ratio R=Gamma(Ks -> pi+pi-gamma)/Gamma(Ks -> pi0pi0)
with the KLOE detector at the DAFNE e+e- collider. This measurement is fully
inclusive with respect to the pi+pi-gamma final state. The sample of over 10^6
two-pion decays of tagged Ks mesons allows a statistical error as low as 0.1%
to be obtained. The accuracy is limited by systematic uncertainties, which are
estimated primarily from data. We find R=2.236 +/- 0.003(stat) +/- 0.015(syst).Comment: 9 pages, 2 Encapsulated Postscript figures. Submitted to Phys. Lett.