0000000000846451
AUTHOR
Elvira Gámiz
Determination of m(s) and vertical bar V-us vertical bar from hadronic tau decays
The mass of the strange quark is determined from SU(3)-breaking effects in the tau hadronic width. Compared to previous analyses, the contributions from scalar and pseudoscalar spectral functions, which suffer from large perturbative corrections, are replaced by phenomenological parametrisations. This leads to a sizeable reduction of the uncertainties in the strange mass from tau decays. Nevertheless, the resulting m(s) value is still rather sensitive to the moment of the invariant mass distribution which is used for the determination, as well as the size of the quark-mixing matrix element \V-us\. Imposing the unitarity fit for the CKM matrix, we obtain m(s)(2 GeV) = 117 +/- 17 MeV, whereas…
and from hadronic tau decays
5 paginas.-- Comunicacion presentada al 9o International Workshop on Tau Lepton Physics (TAU06) celebrado del 19 al 22 de Septiembre en Pisa (Italia).-- arXiv:hep-ph/0612154v1
Charged Kaon CP Violating Asymmetries vs
We present the next-to-leading order full results in Chiral Pertubation Theory for the charged Kaon K → 3 π slope g CP violating asymmetries. We discuss the constraints that a measurement of these asymmetries would impose on the Standard Model results of e K ′ and search for new physics. We also study the kind of information that such measurement can provide on Im G 8 , Im ( e 2 G E ) and higher order weak couplings.
Vusandmsfrom HadronicτDecays
Recent experimental results on hadronic $\ensuremath{\tau}$ decays into strange particles by the OPAL Collaboration are employed to determine ${V}_{us}$ and ${m}_{s}$ from moments of the invariant mass distribution. Our results are ${V}_{us}=0.2208\ifmmode\pm\else\textpm\fi{}0.0034$ and ${m}_{s}(2\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V})=81\ifmmode\pm\else\textpm\fi{}22\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$. The error on ${V}_{us}$ is dominated by experiment and should be improvable in the future. Nevertheless, already now our result is competitive with the standard extraction of ${V}_{us}$ from ${K}_{e3}$ decays, and it is compatible with unitarity.