We report on a measurement of the neutrino-nucleon and antineutrino-nucleon differential cross sections in the CCFR detector. The measurement of the differential cross sections over a wide range of energies allows Delta xF_3 = xF_3(nu)-xF_3(anti-nu) and R to be extracted. Delta xF_3 is related to the difference between the contributions of the strange and charm seas in the nucleon to production of massive charm quark. The results for Delta xF_3 are compared to various massive charm NLO QCD models. The Q^2 dependence of R for x<0.1 has been measured for the first time.
We report on the extraction of the structure functions F_2 and Delta xF_3 = xF_3(nu)-xF_3(nubar) from CCFR nu_mu-Fe and nubar_mu-Fe differential cross sections. The extraction is performed in a physics model independent (PMI) way. This first measurement of Delta xF_3, which is useful in testingmodels of heavy charm production, is higher than current theoretical predictions. The ratio of the F_2(PMI) values measured in nu_mu and nubar_mu scattering is in agreement (within 5%) with the predictions of NLO PDFS using massive charm production schemes, thus resolvin long-standing discrepancy between the two sets of data.
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.
We present the current status of the analysis of about 1.7 billion KSKL pair events collected at DAFNE with the KLOE detector to determine the branching ratio of KS -> pi e nu decay and the lepton charge asymmetry. This sample is ~4 times larger in statistics than the one used in a previous KLOE analysis, allowing us to improve the accuracy of the measurement and of the related tests of CPT symmetry and Delta S = Delta Q rule.
We present a search for the decays B+ -> mu+ nu_mu and B+ -> e+ nu_e in a 253 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy B factory. We find no significant evidence for a signal and set 90% confidence level upper limits of B(B+ -> mu+ nu_mu) < 1.7 x 10^{-6} and B(B+ -> e+ nu_e) < 9.8 x 10^{-7}.
The PEN Collaboration is conducting a new measurement of the pi+ -> e+ nu branching ratio at the Paul Scherrer Institute, with the goal uncertainty of delta B/B(pie2)=5E-4 or lower. At present, the combined accuracy of all published pie2 decay measurements lags behind the theoretical calculation by a factor of 40. In this contribution we report on the PEN detector configuration and its performance during two development runs done in 2007 and 2008.