Comparison of lattice gauge theories with gauge groups Z2 and SU(2)

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transitions are obtained with the current coupled to mesons and their recurrences. The resulting width values are smaller than those conventionally obtained in the naive quark model. The whole picture is only adequate for nonrelativistic configurations, as for the members of the charmoniumor of the T-family and most calculations have been done for transitions among charmed states. To see how far nonrelativistic concepts can be applied, couplings of light mesons are also considered. Comparison

of Lattice

Gauge

Theories

with Gauge

Groups

II. Institut fur Theoretische Physik der Universitat

Z, and SCl(2).

G. MACK

AND V. B. PETKOVA.

Hamburg, Hamburg, West Germany.

We study a model of a pure Yang Mills theory with gauge group ,932) on a lattice in Euclidean space. We compare it with the model obtained by restricting variables to Z, . An inequality relating expectation values of the Wilson loop integral in the two theories is established. It shows that confinement of static quarks is true in our SL1(2) model whenever it holds for the corresponding H,model. The SU(2) model is shown to have high and low temperature phases that are distinguished by a qualitatively different behavior of the ‘t Hooft disorder parameter.

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