Search for active neutrino disappearance in MINOS

MINOS is a long baseline neutrino oscillation experiment with two detectors
separated by a distance of 735 km.  The detectors are exposed to a high
power muon neutrino beam originating at Fermilab.  It has reported a
significant deficit of muon neutrinos at its far detector relative to the
near detector through measurement of the rate of charged-current
interactions. If this deficit is due solely to conversions of muon-neutrinos
to electron- and tau-neutrinos, then the rate of neutral-current (NC)
interactions at the far detector remains unchanged from the non-oscillation
prediction.  Alternatively, if any muon-neutrinos convert to a sterile
state, then the NC rate would be suppressed and the reconstructed energy
spectrum would be distorted.  In this talk I will describe the analysis of
the NC interactions from an exposure of the MINOS detectors to 3.2 x 10^20
protons on target.