Eta and eta' mesons production at COSY-11
Abstract
The low emittance and small momentum spread of the proton and deuteron beams of the Cooler Synchrotron COSY combined with the high mass resolution of the COSY-11 detection system permit to study the creation of mesons in the nucleon-nucleon interaction down to the fraction of MeV with respect to the kinematical threshold. At such small excess energies, the ejectiles possess low relative momenta and are predominantly produced with the relative angular momentum equal to zero. Taking advantage of these conditions we have performed investigations aiming to determine the mechanism of the production of eta and eta' mesons in the collision of hadrons as well as the hadronic interaction of these mesons with nucleons and nuclei. In this proceedings we address the ongoing studies of the spin and isospin dependence for the production of the eta and eta' mesons in free and quasi-free nucleon-nucleon collisions. New results on the spin observables for the vec(p)p --> pp eta reaction, combined with the previously determined total cross section isospin dependence, reveal a statistically significant indication that the excitation of the nucleon to the S11(1535) resonance, the process which intermediates the production of the eta meson in the nucleon-nucleon interactions, is predominantly due to the exchange of the pi meson between the colliding nucleons.
Cite
@article{arxiv.hep-ex/0609035,
title = {Eta and eta' mesons production at COSY-11},
author = {P. Moskal and H. -H. Adam and A. Budzanowski and E. Czerwinski and R. Czyzykiewicz and D. Gil and D. Grzonka and M. Janusz and L. Jarczyk and B. Kamys and A. Khoukaz and P. Klaja and J. Majewski and W. Oelert and C. Piskor-Ignatowicz and J. Przerwa and J. Ritman and B. Rejdych and T. Rozek and T. Sefzick and M. Siemaszko and J. Smyrski and A. Taeschner and P. Winter and M. Wolke and P. Wuestner and W. Zipper},
journal= {arXiv preprint arXiv:hep-ex/0609035},
year = {2010}
}
Comments
Invited talk at MESON 2006: 9th International Workshop on Meson Production, Properties and Interactions, Cracow, Poland, 9-13 Jun 2006