摘要:

Two- and three-body Lorentz invariant phase-space volumes are given in terms of covariant variables. Examples in the use of covariant variables for two- and three-body final-state problems are given and methods which may reduce the labor in the analytic integrations for involved problems are discussed. In the Appendix of this paper four-body phase-space procedures are summarized.

ISSN:0002-9505    

DOI:10.1119/1.1971204

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

From the relativity principle and the conservation of energy in particle collisions we deduce the form of the energy function, and the conservation of inertial mass and three-momentum. We show that the arguments are parallel under Einsteinian and Galilean kinematics.

ISSN:0002-9505    

DOI:10.1119/1.1971205

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Sixteen books are identified as those most often recommended as supplementary reading in introductory physics textbooks.

ISSN:0002-9505    

DOI:10.1119/1.1971206

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The δ-function of current which represents an electron traveling in a straight line is Fourier analyzed into a spectrum of infinite linear harmonic currents, having spectral distributions both in frequency and phase velocity. The radiation (and induction) fields associated with these currents are associated either with Cherenkov radiation or with acceleration or deceleration radiation (“bremsstrahlung” in the literal sense) according to whether the velocity of the electron exceeds or is less than that of light in the medium. The analysis of the two situations is identical; indeed, the two types of radiation cannot, in general, be sharply distinguished.

ISSN:0002-9505    

DOI:10.1119/1.1971132

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Special relativity excludes the existence of rigid bodies, since such bodies can be used to transmit signals instantaneously. It is pointed out that the uncertainty principle requires that a force of orderhc/l2must be available if a rigid body of lengthlis to be used to produce such a violation of relativistic causality; a condition which is particularly stringent in the domain of elementary particles. Thus, where a force of this magnitude is not available, the treatment of bodies of lengthlas rigid may be valid.

ISSN:0002-9505    

DOI:10.1119/1.1971133

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A simple discussion of the pressure-temperature relation during sublimation of a multi-component solid is presented. The assumptions and limitations are shown explicitly, and experimental verification of the applicability of this analysis is discussed.

ISSN:0002-9505    

DOI:10.1119/1.1971135

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The meaning and importance of single particle (SP) states in nuclear shell theory is outlined, and the method of determining them from studies of deuteron stripping reactions is described. The results on locations of SP states are summarized and analyzed to obtain information on the shell theory potential. The depth of this potential is found to have a symmetry energy dependence somewhat weaker than that for optical model potentials for protons. The “self-binding energy,” a lowering of the energy of a SP state as it fills, plays an important role; its magnitude is determined and an empirical expression for it is given. Special neutron-proton interactions must be taken into account in a few cases. The spin-orbit potential seems to be of the formf(r)σ·lwheref(r) = r−1dV/dr; a volume or a simple surface force are excluded. The explicitl-dependence of SP energies is much less than that commonly used, and indicates that the potential is much closer to an oscillator than to a square well in shape. The spacings between major shells require a velocity dependent potential corresponding to an effective mass of 1.3 times the nucleon mass. The shift of SP energies withAindicates that the well gets shallower with increasingA; the depth change is about 5.8 MeV from Ca to Pb. Locations of neutron giant resonances are estimated.

ISSN:0002-9505    

DOI:10.1119/1.1971136

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The foundations of the special theory of relativity are examined in a new form which is more in keeping with the space-time symmetry of the resulting theory, and which employs those concepts which are most directly related to actual observation. The transformation group to which one is immediately led is the conformal mappings of the two-sphere, which, as is well known, is isomorphic to the homogeneous improper orthochronous Lorentz group. In order to obtain extensions to the Poincare group and/or the Einstein group of general relativity, additional assumptions are required.

ISSN:0002-9505    

DOI:10.1119/1.1971138

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The construction and operation of a two-dimensional air-table that yields quantitative linear momentum data are described. The air cushion is provided by running compressed air into a rectangular box whose top surface is perforated with many small holes on the intersections of an illustrated rectangular grid. The data are obtained by arranging that a trace of the motion of each puck is made on a sheet of paraffined paper by a1/60-sec spark timer. The apparatus makes possible the quantitative study of the conservation of linear momentum in two dimensions. These air tables have been used in the elementary physics laboratories at The Pennsylvania State University since the fall of 1962.

ISSN:0002-9505    

DOI:10.1119/1.1971140

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

An experiment is described which demonstrates the diffusion of interstitial impurities in alpha iron. It consists in the measurement of the logarithmic decrement of the oscillatory motion of a torsional pendulum utilizing a commercially available iron suspension wire of high purity. From the results obtained over a conveniently small temperature range, the activation energy for diffusion of the predominant impurity—nitrogen—can be found. This energy agrees favorably with earlier determinations made over a much wider temperature range using iron wire with specially introduced impurities.

ISSN:0002-9505    

DOI:10.1119/1.1971142

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP