PHOTOPRODUCTION OF THE A2 MESON IN THE REACTION n> -nn+n’?r- AND AN ESTIMATE OF THE A2 3” WIDTH*
نویسندگان
چکیده
We observe production of the A2 meson in the reaction n, -‘n Ir’n+sat 4.3 and 5.25 GeV,. The data is consistent with an OPE production mechanism and we give an estimate ofT(A2-~r) M 0.5 MeV. A similar value for f’(A2 rn) is also obtained using a Vector Dominance Model. I * Work supported in part by the U. S. Atomic Energy Commission. ** f Present address: Physics Department, Tel-Aviv University, Tel-Aviv, Israel. t On leave from Max-Planck Institute, Munich,Germany. tt On leave from DESY, Hamburg, Germ&any. (Submitted to whys. Rev. Letters) The A2 meson is known to decay mainly into pn. Since its spin-parity is believed to be JP = 2+, ’ rt should couple only to transversely polarized p mesons. Under the assumption of Vector Dominance’ (VDM), it should also couple to photons and the decay mode AZ-yn should be substantial. No direct observation of this decay mode so far has been reported. ,’ However, if indeed T(A2ry) is appreciable (.5 MeV) one should be able to observe the photoproduction of A2 mesons via a onepiod exchange mechanism (OPE), for example in the reaction:
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