Yoshimatsu Yokoo

Collective Description of a System of Interacting Bose Particles. I

BS>The collective behavior of the three-dimensional Bose system is investigated. The momentum density operator is modified: the modified momentum density operator is equivalent to the velocity operator of the quantum hydrodynamics. The Hamiltonian is described in terms of collective variables for irrotational motion. Results are compared with other theories. (auth)

Radiative Corrections to Nuclear Beta Decay

Recent investigations on the ra~iative corrections to the lifetime of beta decay, beta-ray spectrum and beta-ray angular di,tribution are briefly reviewed. Explicit formulas of the radiative corrections are given for the asymmetry of the beta-ray angular distribution in polarized nuclei. The asymmetry factor is scarcely affected by these corrections, which i;; independent of the cutoff for the Gamow-Teller transition. Numerical values of the radiative corrections are t~bulated for the beta decays of

Radiative corrections to semileptonic decays of charged hyperons

We have studied the radiative corrections to the lepton energy spectrum in semileptonic hyperon decays. The calculation is performed relativistically for the baryons as well as for the leptons, under the assumption of the effective current-current interaction of the V-ϱA type for the baryonic part. We obtain the explicit formula of radiative corrections to the lepton energy spectrum which we can exactly evaluate in case of charged hyperon decays. Numerical values of the radiative corrections to the decays rate and the shape of the lepton energy spectrum are also given for some decay modes. It is shown that the spectral shape is little affected by the radiative corrections.

Neutral-current effect in lepton pair production with polarized photons

Abstract We have investigated the parity-violating asymmetry for the lepton pair production with circularly polarized photons. Numerical calculations are given in the Weinberg-Salam model.

On the Phonon-Phonon Interaction in a System of Bose Particles

The definite expression of the phonon-phonon interaction in a Bose

Parity-Violating Asymmetry in Lepton Pair Production with Circularly Polarized Photons

ystem is derived up to the order of N-1 in terms of the density operator and its exact canonical conjugate which was introduced in the previous papers. We find some mathematical ambiguity in the course of calculation, and clarify the reason why the different results were obtained so far. The validity of our formalism is discussed from the physical point of view.

Baryon Decays and Unitary Symmetry

The neutral-current effects in the lepton pair production with circularly polarized photon beams have been investigated in unified gauge theories. We derive the parity-violating asymmetry of leptons produced by right- and left-handed photons. Numerical calculations are given for the proton and isoscalar targets in the Weinberg-Salam model. The asymmetry is shown as a function of the lepton energy in some kinematical configurations. We find the parity-violating effects are of the order of w-• for the incident photon energy of 20 Ge V.

Radiative Corrections to Asymmetry and Energy Spectrum of β Rays from Polarized Nuclei

Non-leptonic and leptonic decays of the baryons are quantitatively discussed on the basis of the current-current picture by introducing the axial vector current belonging to the 27dimensional representation of SU(3) instead of the F-type one used in Cabibbos theory. It is shown that the decay .J:+~nrc+ proceeds through a pure P wave and that the P wave is larger than the S wave for the decay .J:+~prc0 • The interaction types of the decays A~p+l-+v and s-~A+Z-+v are predicted to be V -1.1A and V +1.1A, respectively. Another interesting result is the predominance of the 27-dimensional representation part for the axial vector current. It is concluded that Cabibbos currents are not the only ones possible to explain the semi-leptonic processes.