Measurements of the Dalitz Plot Parameters for Decays
G. A. Akopdzhanov, V. B. Anikeev, V. A. Bezzubov, S. P. Denisov, A. A. Durum, Yu. V. Gilitsky, V. M. Korablev, V. I. Koreshev, A. V. Kozelov, E. A. Kozlovsky, V. I. Kurbakov, V. V. Lipaev, A. M. Rybin, A. A. Shchukin, M. M. Soldatov, D. A. Stoyanova, K. I. Trushin, I. A. Vasilyev
State Research Center Institute for High Energy Physics, 142281 Protvino, Moscow reg., Russia
PACS: 13.25.Es, 14.40.Aq
Abstract
The g, h, and k Dalitz plot parameters, which are
coefficients in a series expansion of the squared module of the matrix
element (u, v are
invariant variables), have been measured for
decays using 35 GeV/c
hadron beams at the IHEP (Protvino) accelerator. For the first time
dependences of parameters and fit quality on the π0π0 mass cut were
investigated. It is shown that the above mentioned expansion does not fit
the experimental data near the π+π- mass threshold
and addition of the cubic terms only slightly improves the fit quality.
This result points to the important role of
nonanalytical terms in the matrix element that are connected
with the pion rescattering. The comparison of our data with previous
measurements is presented.
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