Photoproduction of the doubly-strange Ξ hyperons

✍ Scribed by J.W. Price; J. Ducote; J. Goetz; B.M.K. Nefkens

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 314 KB
• Volume: 754
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/j.nuclphysa.2005.02.075

✦ Synopsis

We report on the first measurement of exclusive Ξ -and Ξ 0 photoproduction. The Ξ -states are produced in the reaction γp → K + K + Ξ -, and the Ξ 0 states in γp → K + K + π -Ξ 0 . Identification is made by the unique mass measured as the missing mass of the K + K + (or K + K + π -) system using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A systematic study of the excited Ξ spectrum improves our understanding of the N * and ∆ * states, since the Ξ * states are related to them by SU(3) flavor symmetry. At the highest energies available at Jefferson Lab, we begin to find evidence for known excited Ξ -states in the photoproduction process, and possibly new states at 1770 and 1860 MeV, although we do not have enough statistics to draw a strong conclusion. A search for the Ξ -- 5 (1862) pentaquark state seen by NA49 is made using the process γp → K + K + π + X, but the result is inconclusive for lack of statistics.