Recent Results On Rare K+ Decays From Bnl-E787

Experiment 787, now in progress at Brookhaven National Laboratory (BNL), is designed to measure the process K+→π+νν̄. A preliminary upper limit for this process was recently obtained Γ(K+→π+νν̄/Γ(K+→all)<5×10−9 (90% c.l.). A major upgrade of the experiment will take place in the coming year, involving a new beam line and replacement of several detector components in order to enable higher sensitivity for the measurement.