Υ\Upsilon and Υ\Upsilon^{\prime} Leptonic Widths, aμba_{\mu}^b and mbm_b from full lattice QCD

Aug 25, 2014
22 pages
Published in:
  • Phys.Rev.D 91 (2015) 7, 074514
  • Published: Apr 23, 2015
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Abstract: (APS)
We determine the decay rate to leptons of the ground-state ϒ meson and its first radial excitation in lattice QCD for the first time. We use radiatively improved nonrelativistic QCD for the b quarks and include u, d, s and c quarks in the sea with u/d masses down to their physical values. We find Γ(ϒ→e+e-)=1.19(11)  keV and Γ(ϒ′→e+e-)=0.69(9)  keV, both in good agreement with experimental results. The decay constants we obtain are included in a summary plot of meson decay constants from lattice QCD given in the Conclusions. We also test time moments of the vector current-current correlator against values determined from the b-quark contribution to σ(e+e-→hadrons) and calculate the b-quark piece of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, aμb=0.271(37)×10-10. Finally we determine the b-quark mass, obtaining in the MS¯ scheme, m¯b(m¯b,nf=5)=4.196(23)  GeV, the most accurate result from lattice QCD to date.
Note:
  • 21 pages, 15 figures
  • 12.38.Gc
  • 12.15.Ff
  • 13.20.Gd
  • 14.40.Pq
  • leptonic decay
  • vacuum polarization: hadronic
  • muon: magnetic moment
  • width: leptonic
  • up: mass
  • down: mass