Study of η′→ηπ+ π- Dalitz plot

The Dalitz plot of the eta' -> eta pi(+)pi(-) decay is studied using the datacollected with the VES spectrometer in two different exclusive reactions, pi(-) p -> eta'n (charge-exchange) and pi(-) N -> eta'pi(-) N (diffractive-like production). The eta mesons from eta' decays were detected in the eta -> gamma gamma mode. The coefficients for the matrix element squared decomposition are measured on the largest statistics of eta' decays reported so far; there are similar to 13.6 x 10(3) and similar to 6.5 x 10(3) decays after background subtraction in charge-exchange and diffractive-like production, respectively. (C) 2007 Elsevier B.V. All rights reserved.