Investigation of the I = 2 ϱπ system in πN → h̊ov;πN☆

The I = 2 ϱπ system produced in the reaction π−n → ϱ− π− p is investigated within the framework of the Reggeized charge exchange Deck mechanism. The diagram in which a π and ϱ are exchanged gives rise to an enhancement in the ϱπ effective mass at 1.1 GeV which is nearly independent of beam energy. Experimental evidence for such a state in π−n → ϱ−π−p, and in the related processes π+n → ϱ0π0p and π−p → ϱ−π−Δ++ is discussed. The interpretation of this enhancement as an exotic state on the basis of the duality argument made by Chew and Pignotti is considered.