Facilities

The low-energy separated beams at the AGS provide the world's most intense beams of kaons below 1.0 GeV/c. The LESB-2 line has two branches, selectable by a rotating dipole assembly. In the C-6 position, the momentum dispersed beam is focused on the pivot point of the Moby-Dick spectrometer, which is used for hypernuclear studies. Moby-Dick features an effective resolution of 3.0 MeV and a solid angle acceptance of 18 msr, with a momentum bandwidth of about 12% in p/p. The C8 branch, providing a momentum recombined beam, is useful for investigation of the () reaction for hypernuclear studies. For this purpose, the recently-developed NMS spectrometer at Los Alamos is ideal. It features a pair of cesium iodide calorimeters, bismuth germanate converters, and tracking chambers for conversion vertex determination. The NMS offers a resolution of less than 1.0 MeV coupled with a solid angle acceptance in the range of 10 to 20 msr. The device can be used for direct production of reaction s or those produced in decay of hypernuclear fragments. In either case, its capabilities lead to a major improvement over the performance of existing spectrometers at BNL and KEK, and the opportunity to explore systems which are mirrors of those already produced via the and reactions. Truly high-precision hypernuclear spectroscopy requires a large detector array for coincidence studies with any of these reactions.

The 2 GeV/c beam line at the AGS (D-6) is capable of delivering intense and relatively pure beams of kaons, antiprotons and pions. It provides about negative kaons at 1.8 GeV/c for every protons at 24.0 GeV, with a beam purity in excess of 50% kaons at 1.8 GeV/c. This flux is about 100 times that available at KEK. The cylindrical detector system (CDS) is a general purpose out-of-beam detector for D-6 being designed and constructed in Japan. It has a large acceptance of 65% of 4, good particle identification capability, and a good momentum resolution of 3 MeV/c (FWHM) at 100 MeV/c. It will be used in the identification of doubly-strange systems by the detection of sequential decay pions.

A new, high-resolution, high-acceptance spectrometer for () reactions is urgently needed for exploitation of this beam line for cascade and Lambda-Lambda hypernuclei. Such spectrometer, although designed for use at KEK, is the SKS spectrometer, which has a solid angle of about 100 msr and a resolution of 1 MeV. Such a spectrometer would open up exciting opportunities in double strangeness physics at the AGS D-6 line.