分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-11-10
摘要： From the overlap lattice quark propagator calculated in the Landau gauge, we determine the quark chiral condensate by fitting operator product expansion formulas to the lattice data. The quark propagators are computed on domain wall fermion configurations generated by the RBC-UKQCD Col-laborations with Nf = 2 + 1 flavors. Three ensembles with different light sea quark masses are used at one lattice spacing 1/a = 1.75(4) GeV. We obtain ψ¯ψMS(2 GeV) = (−305(15)(21) MeV)3 in the SU(2) chiral limit.
分类： 物理学 >> 核物理学 提交时间： 2016-09-14
摘要： The ρ meson leptonic decay constant at the physical pion mass is calculated with chiral fermions. Overlap valence quarks are used on the L3×T=483×96 Nf=2+1 domain-wall fermion configurations with light sea quarks at the physical point and the spatial extension of 5.5 fm. The mass of the vector meson ρ is determined to be mρ=775.9±6.0±1.8 MeV, and the valence πρ sigma term is extracted to be σ(val)πρ=9.82(6) MeV from Feynmann-Hellman theorem. By adopting a new method to reduce the noise of the wall-wall correlation functions of hadrons, we obtain the ρ leptonic decay constant fρ=208.5±5.5±0.9 MeV, which is in very good agreement with the experimental value fρ=209.4±1.5 MeV derived from the τ decay τ→ρντ.
分类： 物理学 >> 核物理学 提交时间： 2016-09-02
摘要： We propose a novel type of interpolating field operators, which manifests the hybrid-like configuration that the charm quark-antiquark pair recoils against gluonic degrees of freedom. A heavy vector charmonium-like state with a mass of 4.33(2)GeV is disentangled from the conventional charmonium states in the quenched approximation. This state has affinity for the hybrid-like operators but couples less to the relevant quark bilinear operator. We also try to extract its leptonic decay constant and give a tentative upper limit that it is less than one tenth of that of J/ψ, which corresponds to a leptonic decay width about dozens of eV. The connection of this state with X(4260) is also discussed.
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