Progress report for a research program in neutrino physics, cosmic rays, and elementary particles, 1 October 1974--30 September 1975

The elastic scattering reaction anti ν/sub e/ + e^- → anti ν/sub e/ + e^- under continuing study at the Savannah River Reactor has now yielded a 3.1 standard deviation signal, a result obtained in approximately ¹/₈ the time previously required to obtain a 2.3 standard deviation effect. Operation for several more months can be expected to yield a definitive answer to the question of the existence of this fundamental interaction, providing it is at the V-A level. An improved limit of sigma/sub expt//sigma/sub theory/ less than 4 at 3 standard deviations was obtained for the neutral current reaction anti ν/sub e/ + d → n + p + anti ν/sub e/. Further analysis and consideration of detector designs reaffirms the feasibility of a measurement to test the theoretical predictions of Weinberg--Salam. The double beta decay detector was turned on using ⁸²Se as emitter. It appears to be operating very satisfactorily indeed and initial test runs have yielded a half-life for the 2 neutrino mode of tau/sub 1/2/ greater than 10¹⁹ yrs. In 20 hours of operation no events were seen. Providing the background meets our expectations the system should yield a signal of 1/20 days for a tau/sub 1/2/ = 3 x 10²⁰ yrs, the geochemical value. Early data from the advanced electromagnetic potential search has established an upper limit for the admixture of advanced to retarded components of 10^-6. Considerable improvement is contemplated in these results. (author).