ISSLEDOVANIE SVOISTV MEDLENNYKH $pi$$sup +$-MEZONOV, OBRAZOVANNYKH VO VZAIMODEISTVIYAKH $pi$$sup -$-Xe PRI 9 GeV/c. (Investigation of the Properties of Slow $pi$$sup +$-Mesons Produced in $pi$$sup -$-Xe Interactions at 9 GeV/c).