Reaction pp [FORMULA] pp[FORMULA][FORMULA][FORMULA] as a background for hadronic decays of the [FORMULA] meson
Isospin violating hadronic decays of the [FORMULA] and [FORMULA] mesons into 3[FORMULA] 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 [FORMULA],[FORMULA][FORMULA][FORMULA][FORMULA][FORMULA] is coming from direct three-pion production reactions. In case of the [FORMULA] meson the background for the decays is relatively low ( [FORMULA] 10% . The purpose of this article is to provide an estimate of the direct pion production background for the [FORMULA][FORMULA] 3[FORMULA] decays. Using the inclusive data from the COSY-11 experiment we have extracted the differential cross-section for the pp[FORMULA]pp -multipion production reactions with the invariant mass of the pions equal to the [FORMULA] meson mass and estimated an upper limit for the signal to background ratio for studies of the [FORMULA][FORMULA][FORMULA][FORMULA][FORMULA] decay.