Precision tests of the J/{\psi} from full lattice QCD: mass, leptonic width and radiative decay rate to {\eta}_c
| Autor: | K. Hornbostel, G. P. Lepage, R. J. Dowdall, J. Koponen, Christine Davies, Craig McNeile, E. Follana, G. C. Donald |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Quantum chromodynamics
Physics Condensed matter physics 010308 nuclear & particles physics High Energy Physics::Lattice Astrophysics::High Energy Astrophysical Phenomena High Energy Physics - Lattice (hep-lat) Lattice field theory High Energy Physics::Phenomenology Radiative decay FOS: Physical sciences Lattice QCD 01 natural sciences 3. Good health High Energy Physics - Phenomenology High Energy Physics - Phenomenology (hep-ph) High Energy Physics - Lattice Lattice (order) 0103 physical sciences High Energy Physics::Experiment 010306 general physics QC |
| Zdroj: | Xth Quark Confinement and the Hadron Spectrum |
| Popis: | We calculate the J/{\psi} mass, leptonic width and radiative decay rate to \gamma \eta_c from lattice QCD including u, d and s quarks in the sea for the first time. We use the Highly Improved Staggered Quark formalism and nonperturbatively normalised vector currents for the leptonic and radiative decay rates. Our results are: M_{J/\psi} -M_{\eta_c} = 116.5(3.2) MeV; \Gamma(J/{\psi} to e^+e^-) = 5.48(16) keV; \Gamma(J/{\psi} to \gamma \eta_c) = 2.49(19) keV. The first two are in good agreement with experiment, with \Gamma(J/{\psi} to e^+e^-) providing a test of a decay matrix element in QCD, independent of CKM uncertainties, to 2%. At the same time results for the time moments of the correlation function can be compared to values from the charm contribution to \Gamma(e^+e^- to hadrons), giving a 1.5% test of QCD. Our results show that an improved experimental error would enable a similarly strong test from \Gamma(J/{\psi} to \gamma \eta_c). Comment: 20 pages, 16 figures. Added some text plus a figure and two tables comparing the time moments of the charmonium vector correlator to results extracted from experiment for the charm contribution to e^+e^- -> hadrons. This allows a 1.5% test of QCD. Further minor amendments to the text. Version accepted for publication by Physical Review D |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|