510 research outputs found
The Light Quark Masses with the Wilson Quark Action using Chiral Ward Identities
We present results for the light quark masses for the Wilson quark action
obtained with the PCAC relation for the one-link extended axial vector current
in quenched QCD at . This method leads to a remarkable
improvement of scaling behavior of the light quark masses compared to the
conventional method. We obtain MeV for the averaged up and
down quark mass and MeV for the strange quark mass in the
{\barMS} scheme at GeV.Comment: 3 pages, latex source-file, 2 figures as epsf-file, uses espcrc2.sty.
Poster presented at Lattice 97: 15th International Symposium on Lattice Field
Theory, Edinburgh, Scotland, 22-26 Jul 199
Calculation of decay amplitudes with an improved Wilson fermion action in a nonzero momentum frame in lattice QCD
We present our result for the decay amplitudes for both the
and processes with the improved Wilson fermion action. In
order to realize the physical kinematics, where the pions in the final state
have finite momenta, we consider the decay process in the nonzero momentum frame with momentum on the lattice. Our calculations are carried out with
gauge configurations generated with the Iwasaki gauge action and
nonperturbatively -improved Wilson fermion action at
(), , and on a
() lattice. For these parameters the energy
of the meson is set at that of two-pion in the final state. We obtain , , and for a
matching scale where the errors are statistical. The dependence on
the matching scale of these values is weak. The systematic error arising
from the renormalization factors is expected to be around for and for . Prospects toward calculations with the
physical quark mass are discussed.Comment: LaTeX2e, 19 pages, 5 eps figures, uses revtex4 and graphicx. arXiv
admin note: substantial text overlap with arXiv:1505.05289. Published in PR
Two-Flavor Chiral Phase Transition in Lattice QCD with the Kogut-Susskind Quark Action
A summary is presented of a scaling study of the finite-temperature chiral
phase transition of two-flavor QCD with the Kogut-Susskind quark action based
on simulations on (=8, 12 and 16) lattices at the quark mass of
and 0.01. We find a phase transition to be absent for
, and also quite likely at . The quark mass dependence
of susceptibilities is consistent with a second-order transition at .
The exponents, however, deviate from the O(2) and O(4) values theoretically
expected.Comment: 3 pages, Latex(espcrc2,epsf), 3 ps figures, Poster presented at
Lattice 9
Finite-Temperature Phase Structure of Lattice QCD with Wilson Quark Action
The long-standing issue of the nature of the critical line of lattice QCD
with the Wilson quark action at finite-temperatures, defined to be the line of
vanishing pion screening mass, and its relation to the line of
finite-temperature chiral tansition is examined. Analytical and numerical
evidence are presented that the critical line forms a cusp at a finite gauge
coupling, and the line of chiral transition runs past the tip of the cusp
without touching the critical line. Implications on the continuum limit and the
flavor dependence of chiral transition are discussed.Comment: 13 pages(4 figures), latex (epsf style-file needed), one sentence in
abstract missed in transmission supplied and a few minor modifications in the
text mad
Light quark masses from unquenched lattice QCD
We calculate the light meson spectrum and the light quark masses by lattice
QCD simulation, treating all light quarks dynamically and employing the Iwasaki
gluon action and the nonperturbatively O(a)-improved Wilson quark action. The
calculations are made at the squared lattice spacings at an equal distance
a^2~0.005, 0.01 and 0.015 fm^2, and the continuum limit is taken assuming an
O(a^2) discretization error. The light meson spectrum is consistent with
experiment. The up, down and strange quark masses in the \bar{MS} scheme at 2
GeV are \bar{m}=(m_{u}+m_{d})/2=3.55^{+0.65}_{-0.28} MeV and
m_s=90.1^{+17.2}_{-6.1} MeV where the error includes statistical and all
systematic errors added in quadrature. These values contain the previous
estimates obtained with the dynamical u and d quarks within the error.Comment: 4 pages, 3 figures, revtex4; v2: contents partly modified, published
versio
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