  We show that the low-momentum scattering of vortex-antivortex pairs can lead
to very long-lived oscillon states in 2d Abelian Higgs models. The emergence of
oscillons is controlled by the ratio of scalar and vector field masses,
$\beta=(m_s/m_v)^2$ and can be described as a phase transition in field
configuration space with critical value $\beta_c\simeq 0.13(6)\pm 2 $: only
models with $\beta<\beta_c$ lead to oscillon-like remnants. The critical
behavior of the system obeys a power law $O(\beta)\sim |\beta-\beta_c|^o$,
where $O$ is an order parameter indicating the presence of oscillons and $o =
0.2(2)\pm 2 $ is the critical exponent.
