|
|
|
|
|
|
|
|
The Crystal Ball Program After a successful program of hadron-induced physics at the Brookhaven National Laboratory AGS with the Crystal Ball Spectrometer, it has been moved to the Mainz Microtron (MAMI). There, we are preparing for a program that will study g, po, h, h¢ , w, 2po, etc., production by polarized and unpolarized photons on polarized and unpolarized targets, principally hydrogen and deuterium, and eventually 3He. The starting phase of this program will utilize the present MAMI-B facility (800 MeV), use the TAPS forward wall as an end-cap to the Crystal Ball, and install a charged-particle tracker and particle-identification counter into the central portion of the Crystal Ball. Initially we will use unpolarized targets and beams, but by our second and third years of running, we will be embarking on a program with MAMI-C (1500 MeV) that will include single- and double-polarization measurements in order to investigate the electromagnetic and mesonic coupling of light baryonic states. We plan to measure the differential cross section and asymmetries of g® N® ® N*/D* and the subsequent decay of the nucleon resonances into different final states (mainly neutral) such as popop, pop+n, wp, h¢ p, K+L, KoS+, and other all or mostly neutral-particle final states. We are especially interested in the mostly unmeasured meson production from the neutron. The high acceptance and efficiency of the Crystal Ball and TAPS for photons and neutrons makes this possible. The Crystal Ball is also a unique neutron detector covering nearly 4p sr. Its efficiency is 35% for Tn = 150 MeV. We can measure qn and fn, but not Tn. This allows doing an entirely new program of meson production from neutrons using a deuterium target with detection of po and n (with a spectator proton). The photoproduction of light mesons from the neutron is a virgin field for all intents and purposes. We plan to exploit the Crystal Ball and TAPS to make these measurements. Two GW undergraduates spent the summer of 2003 with our collaborators at Mainz helping in the preparations for this program. We plan for an onsite postdoctoral scientist at MAMI to be fully devoted to this program. |
|
This site is best viewed in Internet Explorer 6.0 or higher.
Send mail to
Web Master with
questions or comments about this web site.
|
