The muon decay parameter delta has been measured by the TWIST collaboration. We find delta = 0.74964 +- 0.00066(stat.) +- 0.00112(syst.), consistent with the Standard Model value of 3/4. This result ...implies that the product Pmuxi of the muon polarization in pion decay, Pmu, and the muon decay parameter xi falls within the 90% confidence interval 0.9960 < Pmuxi < xi < 1.0040. It also has implications for left-right-symmetric and other extensions of the Standard Model.
Precise new data for the reaction \(K^- p \to \pi^0 \Lambda\) are presented in the c.m. energy range 1565 to 1600 MeV. Our analysis of these data sheds new light on claims for the ...\(\Sigma(1580){3/2}^-\) resonance, which (if it exists with the specified quantum numbers) must be an exotic baryon because of its very low mass. Our results show no evidence for this state.
Phys.Rev.Lett.83:1521-1524,1999 An experiment has been performed to search for the muon- and electron-number
non-conserving decay mu+ to e+_gamma. The upper limit for the branching ratio
to be ...GAMMA(mu+ to e+_gamma)/GAMMA(mu+ to e+_nu_nubar) < 1.2e-11 with 90%
confidence.
An experiment has been performed to search for the muon- and electron-number non-conserving decay mu+ to e+_gamma. The upper limit for the branching ratio to be GAMMA(mu+ to e+_gamma)/GAMMA(mu+ to ...e+_nu_nubar) < 1.2e-11 with 90% confidence.
