Study of the branching ratio and charge asymmetry for the decay Ks->pi e nu with the KLOE detector

Abstract

Among some 400 million KsKl pairs produced in e+e- annihilations at DAFNE, about 6500 each of Ks->pi+e-nubar and Ks->pi-e+nu decays have been observed with the KLOE detector. From these, the ratio G(Ks->pienu)/G(Ks->p+p-(g))=(10.19+-0.13)10-4 is obtained, improving the accuracy on BR(Ks->pienu) by a factor of four and providing the most precise test of the DeltaS=DeltaQ rule. From the partial width Gamma(Ks->pienu), a value for f+(K0)Vus is obtained that is in agreement with unitarity of the quark-mixing matrix. The lepton charge asymmetry AS=(1.5+-9.6stat+-2.9syst)10-3 is compatible with the requirements of CPT invariance. The form-factor slope agrees with recent results from semileptonic Kl and K+ decays. These are the first measurements of the charge asymmetry and form-factor slope for semileptonic Ks decays.

arXiv comment20 pages, 5 figures, accepted by Phys. Lett. B

References in corpus (13)

• Improved Calculation of Electroweak Radiative Corrections and the Value of V_ud
• The K -> pi vector form factor at zero momentum transfer on the lattice
• Measurements of the Absolute Branching Ratios for the Dominant KL Decays, the KL Lifetime, and Vus with the KLOE Detector
• Measurements of Semileptonic KL Decay Form Factors
• High statistic measurement of the K- -> pi0 e- nu decay form-factors
• Monte Carlo simulation for radiative kaon decays
• A Measurement of the KL Charge Asymmetry
• Measurement of the Form-Factor Slopes for the Decay KLe3 with the KLOE Detector
• High statistic study of the K- -> pi0 mu- nu decay
• Measurement of the KL meson lifetime with the KLOE detector
• Measurement of K^0_e3 form factors
• Search for the K(L) --> PI0 PI0 E+ E- Decay in the KTeV Experiment
• Measurement of the branching fraction for the decay KS --> pi e nu

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• Flavor Physics in the Quark Sector
• Improved estimates of rare K decay matrix-elements from Kl3 decays
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• Precise measurement of B(K\to eν(γ))/B(K\to μν(γ)) and study of K\to eνγ
• Update on $|V_{us}|$ and $|V_{us}/V_{ud}|$ from semileptonic kaon and pion decays
• Determination of CP and CPT violation parameters in the neutral kaon system using the Bell-Steinberger relation and data from the KLOE experiment
• Radiative corrections to semileptonic beta decays: Progress and challenges
• Precise measurement of Gamma(Ks->pi+pi-(gamma))/Gamma(Ks->pi0pi0) with the KLOE detector at DAFNE
• The Physics of DAFNE and KLOE
• Measurement of the branching fraction for the decay $K_S\to \pi \mu \nu$ with the KLOE detector
• Improved $K_S$ tagging procedure and its impact on physics at KLOE-2
• Measurement of the K_L \to πμνform factor parameters with the KLOE detector
• Measurement of the absolute branching ratio of the K+ -> pi+ pi0 (gamma) decay with the KLOE detector
• Measurement of the absolute branching ratios for semileptonic K+/- decays with the KLOE detector
• Towards a discovery of BSM physics from the Cabibbo angle anomaly
• Vus and lepton universality from kaon decays with the KLOE detector
• A Study of the Radiative Ke3 Decay and Search for Direct Photon Emission with the KLOE Detector
• Status of KLOE-2
• Production of Chern-Simons bosons in decays of mesons
• The KLOE-2 experiment: overview of recent results
• Precision test of the SM with Kl2 and Kl3 decays at KLOE
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• The KLOE-2 Experiment at DAPHNE