153 research outputs found
Heavy-heavy-light quark potential in two approaches
We perform the first study about the heavy-heavy-light quark potential in
lattice QCD and a potential model. We find that the inter-two-quark confining
force is reduced by valence quark motional effects compared to the string
tension.Comment: Talk given at YITP International Symposium: Fundamental Problems in
Hot and/or Dense QCD, Kyoto, Japan, 3-6 March 200
Lattice QCD Analysis for Gluons
Nonperturbative properties of gluons are studied in SU(3) lattice QCD at the
quenched level. The first subject is a functional-form analysis of the gluon
propagator in the Landau gauge. We find that the gluon
propagator obtained in lattice QCD is well described by
the four-dimensional (4D) Yukawa-type function with MeV for the Euclidean 4D distance fm. In momentum space,
the gluon propagator ( GeV) is
found to be well approximated with a new-type propagator of ,
which corresponds to 4D Fourier image of the Yukawa-type function. Associated
with the Yukawa-type gluon propagator, we derive analytical expressions for the
zero-spatial-momentum propagator , the effective mass ,
and the spectral function of the gluon field. The mass parameter
turns out to be the infrared effective mass of gluons. The obtained gluon
spectral function is almost negative-definite for ,
except for a positive -functional peak at . The second
subject is a lattice-QCD determination of the relevant gluonic
momentum-component for color confinement. As a remarkable fact, the string
tension is found to be almost unchanged even after cutting off the
high-momentum gluon component above 1.5 GeV in the Landau gauge. In fact, the
relevant gluonic scale for color confinement is concluded to be below 1.5 GeV.Comment: Invited talk at International Workshop on QCD Green's Functions,
Confinement, and Phenomenology - QCD-TNT09, September 07 - 11 2009, ECT
Trento, Ital
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