5,835 research outputs found

    Lepton Polarization Asymmetry in B l l(bar) decays in R-parity violating Minimal Supersymmetric Standard Model

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    We study the implication of R-parity violating Rp Minimal Supersymmetric Standard Model (MSSM) model in lepton polarization asymmetry ALP in B l l(bar) decays . The analysis show that the ALP is significant in a certain phenomenological parametric region of Yukawa couplings. We have also placed indirect bounds on Lambda' lambda couplings as obtained from B t t(bar).Comment: 6 pages, 4 figures Changes of notation in Eq(8-11,17-19),Eq.20 adde

    Measurement of hadronic cross section and preliminary results on the pion form factor using the radiative return at DAPHNE

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    In the fixed energy environment of the e+ee^{+}e^{-} collider DAΦ\PhiNE, KLOE can measure the cross section of the process e+ee^{+}e^{-} \to hadrons as a function of the hadronic system energy using the radiative return. At energies below 1 GeV, e+eρπ+πe^{+}e^{-} \to \rho \to \pi^{+}\pi^{-} is the dominating hadronic process. We report here on the status of the analysis for the e^{+}e^{-} \to \ppg channel, which allows to obtain a preliminary measurement of the pion form factor using an integrated luminosity of 73pb1\sim73 pb^{-1}.Comment: Invited talk at the Seventh International Workshop on Tau Lepton Physics (TAU02-WE07), Santa Cruz, Ca, USA, Sept 2002, 9 pages, LaTeX, 9 eps figure

    Measurements of the Absolute Branching Ratios for the Dominant KL Decays, the KL Lifetime, and Vus with the KLOE Detector

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    From a sample of about 10^9 Phi mesons produced at DAFNE, we have selected KL mesons tagged by observing KS->pi+pi- decays. We present results on the major KL branching ratios, including those of the semileptonic decays needed for the determination of Vus. These branching ratio measurements are fully inclusive with respect to final-state radiation. The KL lifetime has also been measured.Comment: Submitted to Phys. Lett.

    Measurement of the branching fraction for the decay KS --> pi e nu

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    We present a measurement of the branching ratio BR(KS --> pi e nu) performed using the KLOE detector. KS mesons are produced in the reaction e+ e- --> phi --> KS KL at the DAFNE collider. In a sample of about 5 million KS-tagged events we find 624 +- 30 semileptonic KS decays. Normalizing to the KS --> pi+ pi- count in the same data sample, we obtain BR(KS --> pi e nu) = (6.91 +- 0.37) 10^-4, in agreement with the Standard Model expectation.Comment: 9 pages, 5 Encapsulated Postscript figures. Submitted to Phys. Lett.

    Determination of CP and CPT violation parameters in the neutral kaon system using the Bell-Steinberger relation and data from the KLOE experiment

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    We present an improved determination of the CP and CPT violation parameters Re(epsilon) and Im(delta) based on the unitarity condition (Bell-Steinberger relation) and on recent results from the KLOE experiment. We find Re(epsilon) = (159.6 \pm 1.3)10^-5 and Im(delta) = (0.4 \pm 2.1)10^-5, consistent with no CPT violation.Comment: Submitted to JHE
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