Status of the Chorus experiment

The CHORUS experiment at CERN searches for νμ ↔ ντ oscillations by looking for τ decays from charged-current ντ interactions. The emulsion target of the detector, having a resolution of about a micron, enables the detection of the decay topology of the τ. After having analyzed a sample of 126000 events containing an identified muon and 7500 purely hadronic events, no ντ candidate has been found. This result translates in a limit on the mixing angle sin22θμτ < 8 × 10−4 at 90% C.L. for large Δm μτ 2 .