0000000000327770
AUTHOR
G.p. Lepage
Bottomonium precision tests from full lattice QCD: Hyperfine splitting, Υ leptonic width, and b quark contribution to e+e− → hadrons
We calculate the mass difference between the \ud Υ\ud and \ud η\ud b\ud and the \ud Υ\ud leptonic width from lattice QCD using the Highly Improved Staggered Quark formalism for the \ud b\ud quark and including \ud u\ud , \ud d\ud , \ud s\ud and \ud c\ud quarks in the sea. We have results for lattices with lattice spacing as low as 0.03 fm and multiple heavy quark masses, enabling us to map out the heavy quark mass dependence and determine values at the \ud b\ud quark mass. Our results are: \ud M\ud Υ\ud −\ud M\ud η\ud b\ud =\ud 57.5\ud (\ud 2.3\ud )\ud (\ud 1.0\ud )\ud M\ud e\ud V\ud (where the second uncertainty comes from neglect of quark-line disconnected correlation functions) and decay…
Improved Vcs determination using precise lattice QCD form factors for D → Kℓν
We provide a 0.8%-accurate determination of \ud V\ud c\ud s\ud from combining experimental results for the differential rate of \ud D\ud →\ud K\ud semileptonic decays with precise form factors that we determine from lattice QCD. This is the first time that \ud V\ud c\ud s\ud has been determined with an accuracy that allows its difference from 1 to be seen. Our lattice QCD calculation uses the Highly Improved Staggered Quark (HISQ) action for all valence quarks on gluon field configurations generated by the MILC collaboration that include the effect of \ud u\ud , \ud d\ud , \ud s\ud and \ud c\ud HISQ quarks in the sea. We use eight gluon field ensembles with five values of the lattice spacin…