Strong interactions in pionium

Pionium is investigated in various pion-pion strong interactions which reproduce well the pion-pion scattering data. It is found that the ground-state pionium wave functions in those realistic pion-pion strong interactions are considerably different from the hydrogenlike one at small distance. One may suggest that some pion-pion interactions may need to be largely improved before applied to the pion-pion atomic system

Reaction of electron-positron to omega and pi mesons and rho(1450) and rho(1700) mesons in quark model

The investigation in the work of the reaction electron-positron to omega and pi0 mesons in the 3P0 nonrelativistic quark model reveals that the reaction electron-positron to omega and pi0 mesons process at the energy region from the omega and pi mesons threshold to 2.0 GeV is dominated by the two-step process in which the primary quark-antiquark pair first forms rho and rho' mesons and then the vector mesons decay into omega and pi. With rho(1450) and rho(1700) mainly in 2S and 1D states respectively, the experimental data for the cross section of the reaction electron-positron to omega and pi0 mesons are well produced in the 3P0 quark model. The work supports the argument that rho(1450) is mainly a 2S meson and rho(1700) a 1D meson.Comment: 8 pages, 2 figure

Electron-Positron Annihilation into Hadron-Antihadron Pairs

The reactions of electron-positron to nucleon-antinucleon pairs are studied in a non-perturbative quark model. The work suggests that the two-step process, in which the primary quark-antiquark pair forms first a vector meson which in turn decays into a hadron pair, is dominant over the one-step process in which the primary quark-antiquark pair is directly dressed by additional quark-antiquark pairs to form a hadron pair. To reproduce the experimental data of the reactions of electron-positron to proton-antiproton and electron-positron to neutron-antineutron a D-wave omega-like vector meson with a mass of around 2 GeV has to be introduced.Comment: 15 pages, 6 figure

pD atoms in realistic potentials

The pD atoms are studied in various realistic, popular NN potentials. The small energy shifts and decay widths of the atoms, which stem from the short-ranged strong interactions between the antiproton and deuteron, are evaluated in a well-established, accurate approach based on the Sturmian functions. The investigation reveals that none of the employed potentials, which reproduce the NN scattering data quite well, is able to reproduce the experimental data of the energy shifts of the 2p pD atomic states. The energy shifts of the 2p pD atomic states are very sensitive to the strong interactions, hence the investigation of the pD atoms is expected to provide a good platform for refining the NN interaction, especially at zero energy

A Pionic Hadron Explains the Muon Magnetic Moment Anomaly

A significant discrepancy exists between experiment and calculations of the muon's magnetic moment. We find that standard formulas for the hadronic vacuum polarization term have overlooked pionic states known to exist. Coulomb binding alone guarantees $\pi^+ \pi^-$ states that quantum mechanically mix with the $\rho$ meson. A simple 2-state mixing model explains the magnetic moment discrepancy for a mixing angle of order $\alpha \sim 10^{-2}$. The relevant physical state is predicted to give a tiny observable bump in the ratio R(s) of $e^+ e^-$ annihilation at a low energy not previously searched. The burden of proof is reversed for claims that conventional physics cannot explain the muon's anomalous moment.Comment: 14 pages, 2 figures, revised version, accepted for publication in Physics Letters