Tsutomu Yanagida

CP Violation and Off-Diagonal Neutral Currents

We discuss the CP violation based on the SU(2) ×U(1) ×SU_F(2) gauge model, where the new gauge bosons S_µ^i are introduced in association with the extra subgroup SU_F(2). The effective coupling constant G_S for the interaction mediated by the S_µ^i is found to be G_S/G_F > 5 ×10^-6. In this model the gauge bosons S_µ^i are coupled to off-diagonal neutral currents. The ratio R = [ Γ(K^± →π^± e µ) + Γ(K^± →π^± µe ] / Γ(K^- →π^0 µν_µ) is predicted to be R > 2 ×10^-9.

t- and u-Channel Structure of Non-Resonant π-N Scattering Amplitudes at Low Energies

We analyze the t- and u-channel structure of non-resonant amplitudes of low-energy 77:-N scattering, assuming the one-particle-exchange modes. We obtain good agreement with the experimental amplitudes with the p·coupling of normal strength and with the 77:N-coupling about half of the usual strength, which may be interpreted as a reflection of the duality structure. The result for the scalar-meson exchange is compared with the low-energy Pomeron introduced previously.

Low-Energy Pomeron

\Ve discuss some consequences of the hypothesis that the Pomeron has the component coupled with the trace of the energy·momentum tensors of hadrons and dominant at low energies. We may assume that the Pomeron has two components, P(s, t) and D(s, t), which couple with hadrons through the energy-momentum tensors and their traces, respectively. In order to give the s-channel helicity conservation, P ( s, t) has to dominate the scattering amplitude at high energies, while D(s, t) is expected to play the leading role for disconnected quark diagrams at low energies, producing the effects like the exchange of the entity with the transformation properties JG=O+, JP0 =0++.v The purpose of this paper is to discuss some consequences of the hypothesis about low-energy hadronic processes.