Showing papers by "Victor F. Weisskopf published in 1978"
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TL;DR: The existence of nuclear fission could have been predicted before it was found if the theoretical physicists at that time had shown a little more inventiveness as discussed by the authors, which is a simple consequence of the fact that the Coulomb repulsion increases with the square of the number of protons and the nuclear attraction only with the first power.
Abstract: Forty years ago Otto Hahn and Fritz Strassmann discovered fission. The existence of this phenomenon could have been predicted before it was found if the theoretical physicists at that time had shown a little more inventiveness: It is a simple consequence of the facts that the Coulomb repulsion increases with the square of the number of protons and the nuclear attraction only with the first power. In 1938 enough was known about the nuclear force that it would not have been too hard to conclude that the nucleus must become unstable against a split in two parts around atomic number Z = 90.
17 citations
TL;DR: In this article, a simplified model is introduced which yields relations for physical quantities by elementary methods, and the dependence of these quantities on the parameters of the star and on the fundamental constants of nature is exhibited.
Abstract: In order to understand the fundamental properties of a star in radiative equilibrium, a simplified model is introduced which yields relations for physical quantities by elementary methods. In particular, the dependence of these quantities on the parameters of the star and on the fundamental constants of nature is exhibited. Numerical evaluation of these relations is in good agreement with observation and with more elaborate calculations.
9 citations
TL;DR: The European Physical Society was inaugurated on the 26 September 1968 and will be celebrating the tenth anniversary of its foundation during the forthcoming York conference on 'Trends in physics'. The Institute of Physics is honoured to be host for this, the fourth, EPS general conference and is devoting most of this special issue of Physics Bulletin to reviews by eminent physicists of the last ten years as mentioned in this paper.
Abstract: The European Physical Society was inaugurated on the 26 September 1968 and will be celebrating the tenth anniversary of its foundation during the forthcoming York conference on 'Trends in physics'. The Institute of Physics is honoured to be host for this, the fourth, EPS general conference and is devoting most of this special issue of Physics Bulletin to reviews by eminent physicists of the physics of the last ten years.
3 citations
TL;DR: A survey of new developments in particle physics during the last ten years, including the experimental evidences for the existence of different kinds of quarks, neutral currents, and the new theoretical ideas on the relations between weak and electromagnetic forces, on quantum-chromo-dynamics and on the bag-theory of hadrons can be found in this article.
Abstract: — A survey of new developments in particle physics during the last ten years, including the experimental evidences for the existence of different kinds of quarks, neutral currents, and the new theoretical ideas on the relations between weak and electromagnetic forces, on quantum-chromo-dynamics and on the bag-theory of hadrons. The last decade has brought many new discoveries and ideas into particle physics. Indeed some participating scientists are a little over-optimistic today when they state that the most important problems are about to be solved, just as some of them were too pessimistic ten years ago when it seemed to them that particle physics was at a stand-still. What has happened during the last ten years ? Most of it had to do with an accumulating evidence that hadrons are composite entities made up of partons or quarks, whatever name you may choose. Since new physics nearly always starts with experiments , let me first quote a few of the relevant ones made in the last decade. 1. New experiments, strong interactions. — I start with the so-called M.I.T.-SLAC experiment carried out under the leadership of R. Taylor, Jerome Friedman and H. Kendall. In some ways, it is the analogue of the Rutherford experiment of 1911 in which it was shown that the electric charge in the atom is concentrated within a small volume by observing large scattering angles when atoms were bombarded by energetic a-particles. In the M.I.T.SLAC experiments energetic electrons were scattered by protons and relatively large scattering angles were observed, a fact which again points to the concentration of the protonic charge within small units, much smaller than the dimensions of the charge distribution over the proton. Here we have something like a direct experimental evidence for the presence of charge subunits, the quarks. The existence of these subunits was already strongly suspected when experiments revealed a rich spectrum of different hadron states with quantum numbers and other properties pointing towards a definite internal structure. It was M. Gell-Mann and G. Zweig who interpreted the lowest states of the spectrum as consequence of a three-quark structure in the case of the baryons and a quark-antiquark structure in the case of the mesons. Both the analysis of hadron spectroscopy and the results of the M.I.T.-SLAC experiment indicated the following properties of the quarks : they are particles with spin 1/2, and possess fractional charges, 2/3 and — 1/3 of the protonic charge. In order to explain the presently known hadron states, one must assume four different kinds of quarks, named by the letters u, d, s, c, whose charges, isotopic spins, strangeness and charm are listed in table I. The existence of the charmed quark was most spectacularly supported by the discovery of the J/i]/
1 citations
1 citations