Prospects for neutrino oscillation experiments at the CERN SPS

Abstract

Two new experiments, WA95 (CHORUS) and WA96 (NOMAD), to search for v~t-v x oscillations in the wide-band neutrino beam from the CERN 450 GeV SPS were approved in 1991. The method adopted by both experiments consists in detecting xproduction with a sensitivity which corresponds to a vx/v~t ratio o f 2 x 10 -4. Such a value is approximately three orders of magnitude larger than the value expected from the process + p + N --> D s + anything at the proton target, + followed by the decay D s ---> X+Vx. The observation of x-production could only result, therefore, from v~t-Vx oscillations. The two experiments are installed in the extension of the SPS West Area which housed the big bubble chamber BEBC, with the CHORUS detector located just upstream of NOMAD at a distance of 820 m from the proton target. Figure 1 shows the expected neutrino energy spectrum at the CHORUS detector. The distance between the proton target and the end of decay tunnel is 414 m. Both experiments are expected to start taking data in the spring of 1994. 106