  A search for new physics in the acoplanar jet topology has been performed in
2.5 fb-1 of data from ppbar collisions at sqrt(s)=1.96 TeV, recorded by the D0
detector at the Fermilab Tevatron Collider. The numbers of events with exactly
two acoplanar jets and missing transverse energy are in good agreement with the
standard model expectations. The result of this search has been used to set a
lower mass limit of 205 GeV at the 95% C.L. on the mass of a scalar leptoquark
when this particle decays exclusively into a quark and a neutrino. In the
framework of the Little Higgs model with T-parity, limits have also been
obtained on the T-odd quark mass as a function of the T-odd photon mass.
