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William J Marciano

Publications and source records attributed to William J Marciano.

3 recordsLinked to original sources
PubMed2006

Improved calculation of electroweak radiative corrections and the value of Vud.

A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described. It employs high order perturbative QCD results originally derived for the Bjorken sum rule along with a large QCD-motivated interpolating function that matches long- and short-distance loop contributions. Applying this approach to the extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vud from superallowed nuclear beta decays reduces the theoretical loop uncertainty by about a factor of 2 and gives Vud=0.97377(11)(15)(19). Implications for CKM unitarity are briefly discussed.

Journal Article↗
PubMed2004

Precise determination of |V(us)| from lattice calculations of pseudoscalar decay constants.

Combining the ratio of experimental kaon and pion decay widths, Gamma(K-->munu (mu)(gamma))/Gamma(pi-->munu (mu)(gamma)), with a recent lattice gauge theory calculation of f(K)/f(pi) provides a precise value for the Cabibbo-Kobayashi-Maskawa quark mixing matrix element |V(us)|=0.2219(25) or if three generation unitarity is assumed |V(us)|=0.222 1(24). Comparison with other determinations of that fundamental parameter, implications, and an outlook for future improvements are given.

Journal Article↗