Bootstrap quark model and spectra masses, electromagnetic properties of   low-lying hadrons
  The paper is devoted to the construction of low-energy quark scattering amplitudes. Bootstrap quark model allows to describe the light and heavy hadron spectroscopy based on three principles: unitarity, analicity and crossing symmetry. The resulting quark interaction appeared to be effectively short-range. This interaction is determined mainly by the exchange in the gluon channel: the constituent-gluon mass appeared to not be small. Our calculation indicates an important role of an interaction which is induced by instantons. Such an interaction is necessary for deriving both the pion mass and $\eta$-$\eta'$ mass splitting. However, due to the rules of $1/N_c$-expansion this interaction influences slightly the other channels while in the $\eta$-$\eta'$ channel it provides the correct values of masses and gives the angle of $\eta_1-\eta_8$ mixture close to that of the quark model. We discuss the possibility of constructing the amplitudes which take into account the quark confinement. 
S.M. Gerasyuta (Dept. of Physics, Technical Academy, St.Petersburg),   S. Bielefeld (Max-Planck-Institut f\"ur Kernphysik, H...