Se p 19 99 Production of the π − , π 0 in the reaction d ( e , pp ) e ′ π − π 0

Recently, the differential yield and target asymmetry of the reaction d(e, pp)eπ on the tensor polarized deuterium target have been presented in [1, 2], where the experimental procedure and basic assumption were described. A precise treatment of this reaction needs to investigate the reaction channels with an additional neutral pion production as a background to the leading reaction of a single π production. We considered for this background process the pole mechanism and the two body mechanism. In the latter the ∆-isobar and the pion are produced on one nucleon followed by the absorption of the pion on the second nucleon producing another ∆-isobar. The final proton-pion systems come from the decay of the ∆+ and ∆0. In this work we estimated the contribution of the reaction with additional π0 production into whole yield for the different polarization states of the deuteron. In a study of the d(e, pp)X reaction at electron energy 2GeV , the momenta of both protons from 0.3 to 0.7 GeV/c and proton emission angles 64 − 83 approximately 900 proton proton coincidences were analyzed [1, 2]. The cross section of the process initiated by electrons was expressed in terms of the cross section of a reaction induced by virtual photons: γd → ppX . (1) In the forward scattering approximation a virtual photon can be replaced by a real photon. Assuming that only a single π were produced, the photon energy 1 This work was supported by Russian Foundation for Basic Research N 98-02-17993, N 98-0217949 and by grant N 96-0424 from INTAS.