  The superconducting transition is studied within the one-loop renormalization
group in fixed dimension $D=3$ and at the critical point. A tricritical
behavior is found, and for $\kappa > \kappa_c$, an attractive charged fixed
point, distinct from that of a neutral superfluid. The critical exponents of
the continuous transition are evaluated, and it is shown that the anomalous
dimension of the gauge field equals unity. This implies the proportionality of
the magnetic field penetration depth and the superconducting correlation length
below the transition. The penetration depth exponent is nonclassical. We argue
that it can not be extracted from the dual theory in a straightforward manner
since it is not renormalized by fluctuations of the dual field.
