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A theory of gravitation
ABSTRACTS
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243
Neutron Strength Funciiom and Azwage Total Cross Sections. II. The Behavior of the Average Cross Sections and the S-Ware Scattering Lengths. W. F. E. PINEO, M. DIVADEENAM, E. G. BILPUCH, K. K. SETH, AND H. W. NEWSON. Triangle Universities Nuclear Laboratory and Duke lJniversity, Durham, North Carolina 27706. Average neutron total cross sections have been measured in the keV region for natural samples of KCI, SC, V, Mn, Co, Cu, Zn, As, Se, RbBr, Csl, Ce, Nd, Gd, Tb, Dy, Ho, and Hg, and for the separated isotopes 141,1dB.148Nd and l~“~l%m. The measurements were combined with those made earlier here (TUNL) and elsewhere to give a total data set which is comprised of the total cross sections for most of the natural elements and many separated isotopes. The cross sections were averaged over hundreds of keV and compare to various optical model calculations. The data are in fair agreement with spherical optical model calculations below A = 140 and in poor agreement for heavier nuclei. The calculations using deformed potentials agree much better with the data, ‘especially above A = 140. The s-, p-, and d-wave strength functions, the s-(or R’) and p-wave phase shifts were extracted from the average cross sections of the nuclei mentioned above by the Duke average cross section method, but in this paper only :ar:x and R’ are discussed (see Part 111 for strength functions). The values of R’, supplemented by those from other measurements, made both here and elsewhere, were compared to available optical model calculations which use deformed optical potentials. The calculations agree fairly well with the data. Measurements of R’ indicate that it rises much more rapidly at A = 140 than would be predicted by the spherical optical model and confirm the rapid rise predicted by the deformed model. Similarly, a rise in R’ is evident around mass number A. ~ SO, however, enough experimental points are not available for a detailed comparison with theory.
Nuclear Single Piorz Production Near Threshold. Z.
GROSSMAN, F. LENZ, AND M. P. LOCHER. Schweizerisches Institut fur Nuklearforschung, CH 5234 Villigen, Switzerland. The dynamics of the reaction “C(p, r*)Y’*’ are investigated by discussing various reaction mechanisms. We show that the process is dominated by a two nucleon mechanism with virtual N* formation. Contributions of N N intermediate states are small in comparison with NN* states. Higher order multiple scatterings are discussed quantitatively. Individual cross sections are given for all 14C final states of less than IO MeV excitation energy (single particle states and collective states of complex structure). The calculations which contain no free parameter, reproduce the experimentally observed selectivity of the reaction both with respect to relative normalisation and shape of the angular distributions. The absolute cross section is close to experiment. Qualitative estimates give the correct order for the ~i’/r ratio.
A Theory qf Graoitation.
NATHAN ROSEN. Department of Physics, Technion-Israel lnstitute of Technology, Haifa, Israel. A theory of gravitation is presented satisfying the covariance and equivalence principles. It makes use of a Riemannian metric tensor g,, , describing the true gravitational field, and a flat-space metric tensor rpv, describing the inertial forces. The field equations have a simple structure !io that, for given ywv , the initial conditions, which are not subject to any constraints, completely determine the solution. The theory gives results in agreement with those of the general relativity theory to the accuracy corresponding to observations at the present time. The static spherically symmetric solution for the field of a point mass has a singularity only at the point, without any “black hole.”
OF
PAPERS
TO APPEAR
IN
FUTURE
ISSUES
243
Neutron Strength Funciiom and Azwage Total Cross Sections. II. The Behavior of the Average Cross Sections and the S-Ware Scattering Lengths. W. F. E. PINEO, M. DIVADEENAM, E. G. BILPUCH, K. K. SETH, AND H. W. NEWSON. Triangle Universities Nuclear Laboratory and Duke lJniversity, Durham, North Carolina 27706. Average neutron total cross sections have been measured in the keV region for natural samples of KCI, SC, V, Mn, Co, Cu, Zn, As, Se, RbBr, Csl, Ce, Nd, Gd, Tb, Dy, Ho, and Hg, and for the separated isotopes 141,1dB.148Nd and l~“~l%m. The measurements were combined with those made earlier here (TUNL) and elsewhere to give a total data set which is comprised of the total cross sections for most of the natural elements and many separated isotopes. The cross sections were averaged over hundreds of keV and compare to various optical model calculations. The data are in fair agreement with spherical optical model calculations below A = 140 and in poor agreement for heavier nuclei. The calculations using deformed potentials agree much better with the data, ‘especially above A = 140. The s-, p-, and d-wave strength functions, the s-(or R’) and p-wave phase shifts were extracted from the average cross sections of the nuclei mentioned above by the Duke average cross section method, but in this paper only :ar:x and R’ are discussed (see Part 111 for strength functions). The values of R’, supplemented by those from other measurements, made both here and elsewhere, were compared to available optical model calculations which use deformed optical potentials. The calculations agree fairly well with the data. Measurements of R’ indicate that it rises much more rapidly at A = 140 than would be predicted by the spherical optical model and confirm the rapid rise predicted by the deformed model. Similarly, a rise in R’ is evident around mass number A. ~ SO, however, enough experimental points are not available for a detailed comparison with theory.
Nuclear Single Piorz Production Near Threshold. Z.
GROSSMAN, F. LENZ, AND M. P. LOCHER. Schweizerisches Institut fur Nuklearforschung, CH 5234 Villigen, Switzerland. The dynamics of the reaction “C(p, r*)Y’*’ are investigated by discussing various reaction mechanisms. We show that the process is dominated by a two nucleon mechanism with virtual N* formation. Contributions of N N intermediate states are small in comparison with NN* states. Higher order multiple scatterings are discussed quantitatively. Individual cross sections are given for all 14C final states of less than IO MeV excitation energy (single particle states and collective states of complex structure). The calculations which contain no free parameter, reproduce the experimentally observed selectivity of the reaction both with respect to relative normalisation and shape of the angular distributions. The absolute cross section is close to experiment. Qualitative estimates give the correct order for the ~i’/r ratio.
A Theory qf Graoitation.
NATHAN ROSEN. Department of Physics, Technion-Israel lnstitute of Technology, Haifa, Israel. A theory of gravitation is presented satisfying the covariance and equivalence principles. It makes use of a Riemannian metric tensor g,, , describing the true gravitational field, and a flat-space metric tensor rpv, describing the inertial forces. The field equations have a simple structure !io that, for given ywv , the initial conditions, which are not subject to any constraints, completely determine the solution. The theory gives results in agreement with those of the general relativity theory to the accuracy corresponding to observations at the present time. The static spherically symmetric solution for the field of a point mass has a singularity only at the point, without any “black hole.”