arXiv subjects
Publications and source records attributed to G. S. Bali.
We present results on spin dependent potentials from lattice simulations of SU(2) gauge theory. The Coulomb like short range part of the central potential is identified as a mixed vector-scalar exchange while the linear long range part is pure scalar.
We show the running coupling as derived from the SU(3) QQ potential and discuss preliminary results on spin dependent heavy quark potentials from high statistics lattice simulations of SU(2) gauge theory. The precision suffices to study scaling properties and lattice artifacts (at short distances). We identify the Coulomb like short range interaction as a mixed vector-scalar exchange. We measure flux tube formation between a static QQ pair over physical distances up to 2 fm, with a spatial resolution as small as .05 fm. Consistency with the string picture is found for separation larger than about 1 fm, with a half width of the profile of approximately .7 fm.
We present results of a high statistics study of the chromo field distribution between static quarks in SU(2) gauge theory on lattices of volumes 16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm at beta=2.5, beta=2.635, and beta=2.74. We establish string formation over physical distances as large as 2 fm. The results are tested against Michael's sum rules. A detailed investigation of the transverse action and energy flux tube profiles is provided. As a by-product, we obtain the static lattice potential in unpreceded accuracy.
We present an extensive study on the direct determination of the running coupling alpha_s from the static quark antiquark force at short distances, in quenched QCD. We find from our high statistics potential analysis that alpha_qq exhibits two-loop asymptotic behaviour for momenta as low as .5 GeV. As a result, we determine the zero flavour Lambda-parameter to be Lambda^0_MSBAR = 0.630(38)\sqrtσ = 293(18)^{+25}_{-63} MeV. A rough estimate of full QCD effects leads to the five flavour value alpha_MSBAR(m_Z) = .102^{+6}_{-11}. A comparison with other lattice results is made.
First results of an ongoing high statistics study of the colour flux distribution around static quark sources in SU(2) gauge theory are presented. The flux tube profiles and widths have been investigated for several quark separations at beta=2.5 and beta=2.74. The results are tested against Michael's sum rules.
We describe the Wuppertal university pilot project in applied parallel computing. We report on a comprehensive high statistics determination of the static quark-antiquark potential and related quantities from quenched quantum chromodynamics. New data for the string tension and the plaquette action for the region 5.5 < beta < 6.8 is presented.
A detailed investigation of the temperature dependence of the spatial string tension $σ_s$ in $SU(2)$ gauge theory is presented. A sustained performance of 3~GFLOPS on a 64K Connection Machine CM-2 equivalent has been achieved. Scaling of $σ_s$ between $β=2.5115$ and $β=2.74$, on large lattices, is demonstrated. Below the critical temperature, $T_c$, $σ_s$ remains constant. For temperatures larger than $2T_c$ the temperature dependence can be parametrized by $σ_s(T) = (0.369\pm 0.014)^2 g^4(T)T^2$, where $g(T)$ is a 2-loop running coupling constant with the scale parameter determined as $Λ_T = (0.076\pm 0.013)T_c$.
We present results of a detailed investigation of the temperature dependence of the spatial string tension in SU(2) gauge theory. We show, for the first time, that the spatial string tension is scaling on the lattice and thus is non-vanishing in the continuum limit. It is temperature independent below Tc and rises rapidly above. For temperatures larger than 2Tc we find a scaling behaviour consistent with sigma_s(T) = 0.136(11) g^4(T) T^2, where g(T) is the 2-loop running coupling constant with a scale parameter determined as Lambda_T = 0.076(13) Tc.
We present high precision results on the static quark-antiquark-potential on 32^4 and smaller lattices, using the standard Wilson action at BETA = 6.0, 6.2, 6.4, and 6.8 on the Connection Machine CM-2. Within our statistical errors (1%) we did not observe any finite size effects affecting the potential values, on varying the spatial lattice extent from 0.9 fm up to 3.3 fm. We find violations of asymptotic scaling in the bare coupling up to BETA = 6.8. We demonstrate that scaling violations on the string tension can be considerably reduced by introducing effective coupling schemes, which allow for a safer extrapolation of LAMBDA_Lattice to its continuum value. We are also able to see and to quantify the running of the coupling from the interquark force. From this we extract the ratio \sqrt{SIGMA}/LAMBDA_L. Both methods yield consistent values for the LAMBDA-parameter: LAMBDA_MSbar = 0.558(-0.007+0.017)\sqrt{SIGMA} = 246(-3+7) MeV.