2005/07/31 by A. Gray, Alan Gray, I. F. Allison +9 · 10 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Lattice (music) #Lattice QCD #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quark #hep-lat #hep-ph
paper · pdf · doi:10.1103/physrevd.72.094507
published as Phys.Rev.D72:094507,2005 · 24 pages, 19 figures. Version to be published. Minor changes made and typographical errors corrected. Experimental leptonic widths updated in section 8
arxiv created 2005/09/16 · openalex publication_date 2005/11/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We show results for the \ensuremathΥ spectrum calculated in lattice QCD including for the first time vacuum polarization effects for light u and d quarks as well as s quarks. We use gluon field configurations generated by the MILC collaboration. The calculations compare the results for a variety of u and d quark masses, as well as making a comparison to quenched results (in which quark vacuum polarization is ignored) and results with only u and d quarks. The b quarks in the \ensuremathΥ are treated in lattice Nonrelativistic QCD through NLO in an expansion in the velocity of the b quark. We concentrate on accurate results for orbital and radial splittings where we see clear agreement with experiment once u, d and s quark vacuum polarization effects are included. This now allows a consistent determination of the parameters of QCD. We demonstrate this consistency through the agreement of the \ensuremathΥ and B spectrum using the same lattice bare b quark mass. A one-loop matching to continuum QCD gives a value for the b quark mass in full lattice QCD for the first time. We obtain mb^MS(mb^MS)=4.4(3) GeV. We are able to give physical results for the heavy quark potential parameters, r0=0.469(7) fm and r1=0.321(5) fm. Results for the fine structure in the spectrum and the \ensuremathΥ leptonic width are also presented. We predict the \ensuremathΥ\ensuremath-\ensuremathηb splitting to be 61(14) MeV, the \ensuremathΥ^\ensuremath'\ensuremath-\ensuremathηb^\ensuremath' splitting as 30(19) MeV and the splitting between the hb and the spin-average of the \ensuremathχb states to be less than 6 MeV. Improvements to these calculations that will be made in the near future are discussed.