  The quark-gluon sea in the hadrons is considered as periodically correlated.
Energy levels of Shrodinger equation with harmonic potential is used for
describing of the spectrum of hadron masses. In the considered cases the
effective potential operating on each particle of ensemble, under certain
conditions becomes square-law on displacement from a equilibrium point. It can
become an explanation of popularity of oscillator potential for the description
of a spectrum of masses of elementary particles. The analysis shows that levels
of periodic potential better agreed to the spectrum of hadron masses, than
levels of other potentials used for an explanation of a spectrum of masses.
