The Research Of Theoretical Calculation Of Cross Section For Proton-Antiproton Annihilating And Producing Double Neutral Pions Under Renormalized Chain-Loop Propagation Of Nucleon-Antinucleon

Nucleon-nucleon interaction is the foundation of nuclear structure and the basic hadron-hadron interaction. So, it has important meaning to research nucleon-nucleon interaction. At present, though there are many theories about nuclear power and nucleon-nucleon interaction, more difficulties exist in both of these theories or models more or less. Only quark model is more successful for strong interaction, especially the experiment fact of the quantum chromo dynamics which is the basic theories of quark interaction, the strong interaction become one basic problem in physics again.In the nucleons interaction, from bringing forward the pion exchange model of Yukawa, though which had solved many problems about strong interaction (nuclear power) and could not become the basic theory because of the limit of itself, it has more applicability yet.In the quantum field theory, the common method for researching particles interaction is the perturbation theory, of which the most problem is the Feynman integral divergences difficulty for considering high step correction, which become the major factor for restricting its development. Based on quantum field theory and perturbation method, this text adopts the neutral pion and nucleon coupling model of Lorentz's invariability to research the cross section calculation of the reaction process for nucleon-antinucleon being annihilated to double pions, solve the divergent difficulty under the frame of the propagator chain-loop approximation, and achieve the cross section calculation for one-loop, two-loop even chain-loop (infinitude-loop) correction.The divergent difficulty of the propagator function integral arisen from chain-loop correction, can be removed via renormalization project so called, which attempt to separate the finite part from the divergent propagator function integral, keep the finite part in meaning of physics,gain the propagator finite value via a series of analytical method (Feynman integral transformation, Wick rotation, large momentum limit integral, and complex function integral etc.), accomplish the propagator radialization correction under one-loop or chain-loop approximation accordingly, and finish the differential cross section at last.The results indicate,that propagator chain-loop correction is contributive for the cross section calculation, and the correction result is very good presented via the perturbation theory.