First measurements of the spin rotation parameters R and A in elastic π p scattering near low-lying pion-nucleon resonances
Bekrenev V. S., Beloglazov Yu. A., Gaditskii V. G., Kovalev A. I., Kozlenko N. G., Kruglov S. P., Kulbardis A. A., Lopatin I. V., Polyakov V. V., Sumachev V. V., Tkach I. I., Trautman V. Yu., Fedorova-Koval' E. P., Filimonov E. A.
The rotation parameters R and A have been measured for the first time in elastic πρ scattering near the low-lying pion-nucleon resonances. The experiment was carried out at an energy of π~ mesons of450 MeV with a polarized proton target, a horizontal spin orientation, and a polarimeter consisting of multigap optical spark chambers with television readout.