The 15th APPEAL Seminar
APPEAL 15-06
Date and Time: July 11th, 2006, 16:00 - 17:00
Place: 1F Auditorium (Main building), SPring-8
Speaker: Prof. A. Titov, JINR/RIKEN
Title: Formation process of Theta+ in inclusive gamma D --> pK^-X reactions
Abstract: We analyze the possibility to produce an intermediate Theta+ via a K+N->Theta+ formation process in gamma D->pK^-X (X=nK+,pK0) reactions at some specific kinematical conditions, in which a pK- pair is knocked out in the forward direction and its invariant mass is close to the mass of Lambda(1520). The Theta+ signal may appear in the [gamma D, pK-] missing mass distribution.
The ratio of the signal (cross section at Theta+ peak position) to smooth background processes varies from 0.7 to 2.4 depending on the spin and parity of Theta+, and it decreases correspondingly if the pK- invariant mass is outside the Lambda(1520)-resonance region. We analyze the recent CLAS result for searching the Theta+ signal in the gamma D-> pK-nK+ reaction and show that the conditions of this experiment greatly reduce a possible manifestation of the Theta+ formation processes making difficult to extract a Theta+ peak from data.
Contact: Prof. Hiro Ejiri. SPring-8/IIAS/RCNP