caa a22 4500 445872926 CHVBK 20180317145517.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1140/epja/i2011-11093-4 doi (NATIONALLICENCE)springer-10.1140/epja/i2011-11093-4 Reaction pp $ \rightarrow$ pp $ \pi$ $ \pi$ $ \pi$ as a background for hadronic decays of the $ \eta^{{\prime}}_{}$ meson [Elektronische Daten] [M. Zieliński, P. Moskal, A. Kupść] Isospin violating hadronic decays of the $ \eta$ and $ \eta{^\prime}$ mesons into 3 $ \pi$ mesons are driven by a term in the QCD Lagrangian proportional to the mass difference of the d and u quarks. The source giving large yield of the mesons for such decay studies are pp interactions close to the respective kinematical thresholds. The most important physics background for $ \eta$ , $ \eta{^\prime}$ $ \rightarrow$ $ \pi$ $ \pi$ $ \pi$ is coming from direct three-pion production reactions. In case of the $ \eta$ meson the background for the decays is relatively low ( $ \approx$ 10% . The purpose of this article is to provide an estimate of the direct pion production background for the $ \eta{^\prime}$ $ \rightarrow$ 3 $ \pi$ decays. Using the inclusive data from the COSY-11 experiment we have extracted the differential cross-section for the pp $ \rightarrow$ pp -multipion production reactions with the invariant mass of the pions equal to the $ \eta{^\prime}$ meson mass and estimated an upper limit for the signal to background ratio for studies of the $ \eta{^\prime}$ $ \rightarrow$ $ \pi^{+}_{}$ $ \pi^{-}_{}$ $ \pi^{0}_{}$ decay. SIF, Springer-Verlag Berlin Heidelberg, 2011 Zieliński M. Institute of Physics, Jagellonian University, PL-30-059, Cracow, Poland aut Moskal P. Institute of Physics, Jagellonian University, PL-30-059, Cracow, Poland aut Kupść A. Department of Physics and Astronomy, Uppsala University, Box 516, 75121, Uppsala, Sweden aut The European Physical Journal A Springer-Verlag 47/8(2011-08-01), 1-6 1434-6001 47:8<1 2011 47 10050 https://doi.org/10.1140/epja/i2011-11093-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1140/epja/i2011-11093-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zieliński M. Institute of Physics, Jagellonian University, PL-30-059, Cracow, Poland aut NATIONALLICENCE 700 1- Moskal P. Institute of Physics, Jagellonian University, PL-30-059, Cracow, Poland aut NATIONALLICENCE 700 1- Kupść A. Department of Physics and Astronomy, Uppsala University, Box 516, 75121, Uppsala, Sweden aut NATIONALLICENCE 773 0- The European Physical Journal A Springer-Verlag 47/8(2011-08-01), 1-6 1434-6001 47:8<1 2011 47 10050 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer