A partial-wave analysis of the etapi- and eta'pi- systems produced in
the reactions pi-N-->eta(eta')pi-N on a beryllium target at a beam mom
entum of p(pi-) = 37 GeV/c is performed. It is shown that (1) all the
waves with negative exchange naturality are negligibly small for both
systems; (2) the matrix element squared of the P+ wave with J(PC) = 1-
+ for the eta'pi- system significantly exceeds that for the etapi- sys
tem, which could testify to the dominance of systems with a valence gl
uon (qqgBAR) in the J(PC)= l-+ wave formation; (3) the ratio R = Br(a2
- --> eta'pi-)/BR (a2- --> etapi-) = (4.7 +/- 1.0(stat.) +/- 0.4 (syst
.)) x 10(-2) has been obtained.