Search for the Θ+ pentaquark in the reaction γd → p K- K+ n

الأصل · EN

A search for the in the reaction γd → pK-K+n was completed using the CLAS detector at Jefferson Lab. A study of the same reaction, published earlier, reported the observation of a narrow resonance. The present experiment, with more than 30 times the integrated luminosity of our earlier measurement, does not show any evidence for a narrow pentaquark resonance. The angle-integrated upper limit on production in the mass range of 1.52 to 1.56 GeV/c² for the γd → pK-Θ+ reaction is 0.3 nb (95% CL). This upper limit depends on assumptions made for the mass and angular distribution of production. Using production as an empirical measure of rescattering in the deuteron, the cross section upper limit for the elementary γn → K-Θ+ reaction is estimated to be a factor of 10 higher, i.e., 3 nb (95% CL).