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Equal-time commutators and non-regge behaviour of photoproduction amplitudes
ABSTRACTS
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ISSUES
and Non-Regge Behaviour of Photoproduction Amplitudes. H. G. DOSCH Institut fur theoretische Physik, der Universitat Heidelberg, Germany. It is shown that fixed poles in photoproduction amplitudes emerge from the equal-time commutators in a natural way, the latter ones being the consequence of an assumed sharply retarded commutator in the reduction formula. We discuss in detail, how the residues of these fixed poles, which under the smoothness assumption are proportional to a strong form factor, can be modified and cancelled. Such a cancellation seems to be rather artifical and necessitates the existence of a Kronecker-delta in the retarded commutator of the pion current and the electromagnetic current. The fixed poles due to the equal time commutators discussed occur only in negative parity helicity amplitudes and, hence, are evasive. Equal-Time AND
S-Wave
Commutators
V. F. MUELLER.
P-Production
in Nucleon-Nucleon
Collisions:
Finite
Mass
Corrections.
JAMES
E. YOUNG.
Univ. of Calif. Los Alamos Scientific Laboratory, T-9 P.O. Box 1663, Los Alamos, New Mexico. The finite-mass corrections to previously obtained zero-mass, threshold, a-production cross sections in NN-collisions are presented. The corrections in question amount to about 8 % for the unbound production process (e.g., p + p +?Y+ + n + p) in Z = 1 states, which is all that is discussed. The technique employed is a combination of the use of spurions and the Fubini-Furlan mass-dispersion method. of the Raman Effect in Metals. D. L. MILLS, A, A. MARADUDIN, AND E. BURSTEIN. Dept. of Physics, Univ. of California, Irvine, Calif. A theory of the Raman scattering of light by the optical vibration modes of polyatomic metals is presented. A microscopic theory has been developed which describes the modulation of the electronic susceptibility tensor x&w) by long wavelength optical phonons. The various mechanisms which contribute to the Raman tensor are discussed. The theory of inelastic scattering of light by a semiinfinite opaque medium has been formulated. We apply the theory to describe the spectrum of light scattered by both even- and odd-parity optical modes of long wavelength. An estimate of the strength of the scattering has been made for two cases, and is compared with experimental results of Feldman, Parker, and Ashkin. Theory
Printed
in Belgium
OF
PAPERS
TO
APPEAR
IN
FUTURE
297
ISSUES
and Non-Regge Behaviour of Photoproduction Amplitudes. H. G. DOSCH Institut fur theoretische Physik, der Universitat Heidelberg, Germany. It is shown that fixed poles in photoproduction amplitudes emerge from the equal-time commutators in a natural way, the latter ones being the consequence of an assumed sharply retarded commutator in the reduction formula. We discuss in detail, how the residues of these fixed poles, which under the smoothness assumption are proportional to a strong form factor, can be modified and cancelled. Such a cancellation seems to be rather artifical and necessitates the existence of a Kronecker-delta in the retarded commutator of the pion current and the electromagnetic current. The fixed poles due to the equal time commutators discussed occur only in negative parity helicity amplitudes and, hence, are evasive. Equal-Time AND
S-Wave
Commutators
V. F. MUELLER.
P-Production
in Nucleon-Nucleon
Collisions:
Finite
Mass
Corrections.
JAMES
E. YOUNG.
Univ. of Calif. Los Alamos Scientific Laboratory, T-9 P.O. Box 1663, Los Alamos, New Mexico. The finite-mass corrections to previously obtained zero-mass, threshold, a-production cross sections in NN-collisions are presented. The corrections in question amount to about 8 % for the unbound production process (e.g., p + p +?Y+ + n + p) in Z = 1 states, which is all that is discussed. The technique employed is a combination of the use of spurions and the Fubini-Furlan mass-dispersion method. of the Raman Effect in Metals. D. L. MILLS, A, A. MARADUDIN, AND E. BURSTEIN. Dept. of Physics, Univ. of California, Irvine, Calif. A theory of the Raman scattering of light by the optical vibration modes of polyatomic metals is presented. A microscopic theory has been developed which describes the modulation of the electronic susceptibility tensor x&w) by long wavelength optical phonons. The various mechanisms which contribute to the Raman tensor are discussed. The theory of inelastic scattering of light by a semiinfinite opaque medium has been formulated. We apply the theory to describe the spectrum of light scattered by both even- and odd-parity optical modes of long wavelength. An estimate of the strength of the scattering has been made for two cases, and is compared with experimental results of Feldman, Parker, and Ashkin. Theory
Printed
in Belgium