The Rare Symmetry Violating Processes project (RSVP) will consist of two experiments at the Brookhaven National Laboratory (BNL) Alternating Gradient Synchrotron (AGS) that will look for rare decay processes of certain elementary particles. If observed, these processes would indicate the existence of new phenomena beyond the Standard Model (SM) of elementary particle physics. Probing rare processes generally involves effects due to virtual-particle production and annihilation, and through these effects one is provided access to particle mass scales much higher than those accessible through direct accelerator production. Initially, the RSVP would construct and carry out two fundamental experiments: MECO (a study of an extremely rare process for conversion of muons to electrons, hence the acronym) and KOPIO (a similarly rare process for studying the decay of neutral kaons into neutral pions). MECO will search for conversion of muons into electrons in the nuclear Coulomb field, an event with a 10-17 probability of occurring. Muon-to-electron conversion is accommodated within the SM, but the basic SM mechanism would produce an event rate far below what is measurable. Instead, MECO will search for excess conversion that would point toward new physics, that is, beyond the SM. KOPIO will explore the world of Charge-Parity (CP) violation, the process by which the observed matter-antimatter asymmetry is thought to have arisen. KOPIO will search for rare decays of neutral kaons into neutral pions and neutrino-antineutrino pairs, a process mediated by direct CP violation and very well understood in terms of the SM. Any deviation from the SM or from similar measurements of CP violation in the B-meson sector would indicate the existence of physics beyond the SM. By either ruling out or characterizing these processes at probability as low as 10-17, the RSVP will help to clarify existing questions and elicit new ones about the fundamental structure of matter. The RSVP will represent the efforts of a 30-institution collaboration involving the United States, Canada, Switzerland, Italy, Japan, and Russia.
Although recommended for approval by the NSB in 2001, overall national budget pressures have delayed budget appropriations for the RSVP. Funding is anticipated in FY 2006, as was indicated in the FY 2004 budget request to Congress.