Forward A$_{2}^{+}$ production in pi+p --> K+$\overline{K}$0$_{S}$p at 12.7 GeV/c

Approximately 350 A/sub 2//sup +/ events have been observed in the reaction pi /sup +/p to K/sup +/K/sub S//sup 0/p(K/sub S//sup 0/ to pi /sup +/ pi /sup -/) at an incident pi /sup +/ laboratory momentum of 12.7 GeV/c. The events are distributed over a range of four-momentum transfer squared 0.01<or=-t<or=0.60 (GeV/c)/sup 2/ and K/sup +/K/sub S //sup 0/ mass 1.11<or=mK/sup +/K/sub S//sup 0/<or=1.51 GeV. A Breit- Wigner fit to the mass spectrum yields a mass for the A/sub 2//sup +/, mA/sub 2//sup +/=1.324+or-0.005 GeV, and a width Gamma /sub 0 /=0.110+or-0.018 GeV. A cross section sigma ( pi /sup +/p to A/sub 2 //sup +/p)=1.71+or-0.30 mu b has been found referring to the above- mentioned mass and t range and A/sub 2//sup +/ to K/sup +/K/sub S//sup 0/ with K/sub S//sup 0/ to pi /sup +/ pi /sup -/. The spin-space density matrix in the Gottfried-Jackson frame is practically saturated by rho /sub 11/ approximately= rho /sub 1-1/=/sup 1///sub 2/ suggesting natural parity exchanges only. There is a forward dip in the angular distribution consistent with dominance of s-channel net helicity flip amplitudes and rho and f Regge exchanges suffice to describe adequately the differential cross sections. (35 refs).