Takeshi Ebata

Strong interaction and QFD

Abstract With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1 2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) × U(1) gauge transformation. Especially the ϱ-meson transformation as a triplet under SU(2) W , and this is the origin of the ϱ-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons.

How to understand the non-leptonic decays of bosons?

Abstract A new weak-isospin ( I W ) assignment for bosons is proposed. This assignment together with I W conservation is equivalent to ΔI = 1 2 rule for K-decays. Application to the decays of new particles yields results which are new or different from the prediction based on SU(3) by a factor 1 2 .

Unified treatment of photon and massive vector-meson scattering process by helicity amplitudes

Abstract A formalism to treat virtual photons and massive vector mesons on the essentially same footing is developed to include the scattering of a massless and massive spin-1 particle by a spin - 1 2 particle . It is explicitly shown that a smooth limit of the massive case amplitudes to the Compton amplitudes can be realized within the framework of helicity amplitudes and that the zero-mass limit satisfies all the requirements of gauge invariance. Such a formalism is advantageous to incorporate the vector-dominance hypothesis and yields a convenient parametrization of helicity amplitudes for the Regge-pole analysis of real and virtual photon processes.

Limiting fragmentation and Bjorken scaling in a baryon exchange model

The target fragmentation in an inclusive reaction is studied in a baryon exchange model. The invariant distribution function expressed by the total cross section of hadron-hadron scattering shows scaling behavior. The calculation is compared with the data. The formalism is also applied to the inclusive reaction by electrons. Possible connection of Bjorken scaling to the limiting fragmentation is discussed. (auth)

Isobar Production in Boson-Nucleon Collision

An attempt is made to understand the successful results of the isobar model analysis by Olsson and Yodh from the dynamical aspect. This is made under the assumption that the isobar is predominantly produced through the exchange of the I= 1, J = 1 di-pion system between the incident boson and the target nucleon, if there is no serious kinematical restriction against the exchange and if there is no other resonances. Such a model ·can be applied to the r~actions rc+p-+2rcN and KN-+KrcN in the lower energy region. The rise of the inelastic cross section is calculated. The fit with the experiment is excellent, especially for rc+p reaction. Although in our model, the isobar is produced mainly in P-state, the results of the usual isobar model, where S-state production is assumed, is little changed And the validity of the model becomes quite plausible, if the particular angular distribution of the isobar stated in the text does not contradict experiment. Partial wave projection of the amplitude is performed, and it is shown that in fact the isobar is produced dominantly in P112 and P312 near the threshold; the elastic amplitudes for P112 and P 312 states, rather than Dr;2 are perhaps to be seriously affected by the rise of the inelastic process. Some discussion is made about the relation between the model and the usual treatments of final state interaction, and treatment of the lowest graph of the vector meson theory. A few remarks are made concerning the re-p reaction, to which the present model cannot be applied because of the effects of the higher resonances.