Correlation Femtoscopy for Studying Eta Meson Production Mechanism
  The high statistics data from the pp -> ppeta reaction measurement, delivered by the COSY-11 collaboration, are now being evaluated using the correlation femtoscopy technique. This method is based on the relative momentum correlations of two emitted protons and may permit determination of the size of the reaction volume. For the very first time, we apply an intensity interferometry technique to study the mechanism of the meson production via the nucleon-nucleon interaction close to the kinematical threshold. We invented a method to determine correlation function for the ppeta system free from the physical multi-pion production background. We show the comparison of experimental results with theoretical predictions and appraise the accuracy achieved for the determination of the size of the emission source. 
P. Klaja, P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwinski, R.   Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk...