Brookhaven AGS Experiment 949 

Required DOE Security Notice

Results (from the first 20% of the running approved by DOE-OHEP)

Although it is clear that additional running is needed to evaluate consistency with the SM prediction, funding for the completion of E949 is not yet available. (The United States Department of Energy's Office of High Energy Physics has neglected to provide the funding to complete the operations of E949 that they approved in August of 1999.)

Description of the experiment

E949 is a rare kaon decay experiment in the C4 beamline (LESB III) at the AGS.
E949 Overview E949 Event
Introduction to E949 (pdf version of poster for Lepton Photon 2003) E949 Event
We are seeking to measure the branching ratio of K+ → π+ ν ν. E949 is a successor experiment to the very successful E787 experiment. E787 was the first experiment to observe this very rare decay. The first event was collected during the 1995 run at the AGS. More information on E787 can be found at the web site, or in the following brief description. The second event was found in the 1998 data set of E787. E949 has substantially upgraded the photon veto system, the trigger, the data acquisition, and several other key detector systems, and plans to run with the full AGS beam intensity (x5 more than was available for the observation of the first event).
E949 Detector Final Result from E787


Run Info, Instructions and Shift Schedule

Midas Database (only from sites), Electronic Logbook for sites or for outside sites

General Information

Detector Information

Papers , Presentations , Technical Notes , In the News

Internal Information (passwd req'd.)

Related Links

Last update: August 18, 2008
Steve Kettell, BNL (