Scaling of gauge balls and static potential in the confinement phase of the pure U(1) lattice gauge theory

We investigate the scaling behaviour of gauge-ball masses and static potential in the pure U(1) lattice gauge theory on toroidal lattices. An extended gauge field action $-\sum_P(\beta \cos\Theta_P + \gamma \cos2\Theta_P)$ is used with $\gamma= -0.2$ and -0.5. Gauge-ball correlation functions with all possible lattice quantum numbers are calculated. Most gauge-ball masses scale with the non-Gaussian exponent $\nu_{ng}\approx 0.36$. The $A_1^{++}$ gauge-ball mass scales with the Gaussian value $\nu_{g} \approx 0.5$ in the investigated range of correlation lengths. The static potential is examined with Sommer's method. The long range part scales consistently with $\nu_{ng}$ but the short range part tends to yield smaller values of $\nu$. The $\beta$-function, having a UV stable zero, is obtained from the running coupling. These results hold for both $\gamma$ values, supporting universality. Consequences for the continuum limit of the theory are discussed.