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THE THEORY OF QUANTIZED FIELDS. PART 3

Description: In this paper we discuss the electromagnetic field, as perturbed by a prescribed current. All quantities of physical interest in various situations, eigenvalues, eigenfunctions, and transition probabilities, are derived from a general transformation function which is expressed in a non-Hermitian representation. The problems treated are: the determination of the energy-momentum eigenvalues and eigenfunctions for the isolated electromagnetic field, and the energy eigenvalues and eigenfunctions for the field perturbed by a time-independent current; the evaluation of transition probabilities and photon number expectation values for a time-dependent current that departs from zero only within a finite time interval, and for a time-dependent current that assumes non-vanishing time-independent values initially and finally. The results are applied in a discussion of the infra-red catastrophe and of the adiabatic theorem. It is shown how the latter can be exploited to give a uniform formulation for all problems requiring the evaluation of transition probabilities or eigenvalue displacements.
Date: May 1, 1953
Creator: Schwinger, J.
Partner: UNT Libraries Government Documents Department

Progress Report No. 50 for the Period June 1, 1957 Through August 31, 1957

Description: Progress is reported in fission elements chemistry, organic and inorganic nuclear chemistry, cosmic ray research, high-energy accelerator experimentation and physics, bubble chamber experimentation, and theoretical physics. Considerable attention was given to the ionization of mineral acids and hydrogen haloraetallates in inorganic solvents and to anion exchnnge behavior in metal complexes. Studies of various chemical reaction mechanisms were continued. The self-energy of a Dirac particle coupled through its charge with the electromagnetic field was investigated without perturbation theory. (For preceding period see AECU-3580.) (D.E.B.)
Date: August 31, 1957
Partner: UNT Libraries Government Documents Department

An Experiment on the Limits of Quantum Electro-Dynamics

Description: The limitations of previously performed or suggested electrodynamic cutoff experiments are reviewed, and an electron-electron scattering experiment to be performed with storage rings to investigate further the limits of the validity of quantum electrodynamics is described. The foreseen experimental problems are discussed, and the results of the associated calculations are given. The parameters and status of the equipment are summarized. (D.C.W.)
Date: June 1, 1959
Creator: Barber, W. C.; Richter, B.; Panofsky, W. K. H.; O'Neill, G. K. & Gittelman, B.
Partner: UNT Libraries Government Documents Department

THE ELECTROMAGNETIC PINCH EFFECT FOR SPACE PROPULSION

Description: The phenomenon of the electromagnetic pinch effect is used to accelerate ionized gases for space propulsion. Electrical energy, initially stored in capacitors, is discharged across two nozzle shaped electrodes wherein the radial pinch is converted to axial motion of the effected gases instead of confinement at the axis. The gas dynamics of a pinch using the hydrodynamical model of a msgnetic piston driving a shock wave is combined with the electrodynamics of the circuit to calculate the discharge behavior. Experiments on three different electrode designs are discussed and results compared with calculated values. Results are applied to one particular space propulsion system consisting of a nuclear energy source, a space radiator, a turbine-generator, capacitor, and a pinch tube. The specific mission analyzed is a one-way unmanned flight to a Mars orbit, starting from an Earth orbit. (auth)
Date: August 1, 1959
Creator: Kunen, A.E. & McIlroy, W.
Partner: UNT Libraries Government Documents Department

THE PARITY OF THE NEUTRAL PION AND THE DECAY pi{sup 0} Yields 2e{sup +} + 2e{sup -}

Description: Two hundred and six electronic decays of the pi{sup 0}, pi{sup 0} yields e{sup +} + e{sup -} + e{sup +} + e{sup -}, were observed in a hydrogen bubble chamber. The decay distributions of the electron pairs and the total rate for this process are shown to be in good agreement with theory. An examination of correlations of the e{sup +}e{sup -} pair decay planes on the basis of electrodynamic predictions is in agreement with the hypothesis that the pi{sup 0} is pseudoscalar, but disagrees for scalar pions by 3.6 standard deviations. (auth)
Date: January 1, 1962
Creator: Samios, N.P.; Plano, R.; Prodell, A.; Schwartz, M. & Steinberger, J.
Partner: UNT Libraries Government Documents Department

Decays of neutral pseudoscalar mesons into lepton pairs

Description: The authors calculate the branching ratio {Lambda}(P {yields} {ell}{sup +}{ell}{sup -})/{Lambda}(P {yields} {gamma}{gamma}) to lowest contributing order in quantum electrodynamics, with a vector meson model for the pseudoscalar meson form factor. They treat the processes {eta} {yields} {mu}{sup +}{mu}{sup -}; {eta} {yields} e{sup +}e{sup -}; K{sub 2}{sup 0} {yields} {mu}{sup +}{mu}{sup -}; K{sub 2}{sup 0} {yields} e{sup +}e{sup -}; {pi}{sup 0} {yields} e{sup +}e{sup -}. Results are compared with those of previous calculations.
Date: September 24, 1968
Creator: Quigg, C. & Jackson, J. D.
Partner: UNT Libraries Government Documents Department

Problems in electromagnetic mass-difference calculations

Description: A brief discussion is given on the progress made thus far in calculating the electromagnetic mass differences of elementary particles. Some of the methods discussed include Feynman's method, Cottinghams method, the methods involving Bjorken scaling iunctions, and the formalism of Dashen and Frautschi. (LBS)
Date: January 1, 1972
Creator: Majumdar, D.P.
Partner: UNT Libraries Government Documents Department

The Direct Production of Electron Pairs in Nuclear Emulsion by 100 and 200 GeV Protons

Description: It is proposed to study the direct production of electron pairs produced when a high energy proton interacts with the Coulomb field of a nucleus. This process occurs at fourth order in quantum electrodynamics. This phenomena, called trident production when the incident particle is an electron, is characterized by a single incident primary track and three emerging tracks. Accelerator experiments on direct pair production by protons have not been previously reported, due to the small cross-sections at energies less than 100 GeV. However, at an energy of 100 GeV the cross-section for the direct creation of electron pairs by protons in emulsion is about 10{sup -25}cm{sup 2}.
Date: July 20, 1972
Creator: Cary, A.S. & College, /Harvey Mudd
Partner: UNT Libraries Government Documents Department

Problems of quantum electrodynamics in heavy-ion collisions

Description: The use of heavy ion reactions in studying basic problems of very strongly bound particles is discussed. Specifically, the fusion of two heavy nuclei, e.g., u + u, to form a superheavy quasimolecule is considered theoretically, with suggestions given for possible experiments. (12 figures) (SDF)
Date: January 1, 1975
Creator: Mueller, B.
Partner: UNT Libraries Government Documents Department

Higher order corrections to energy levels of muonic atoms

Description: In order to facilitate the analysis of muonic x-ray spectra, the results of numerical computations of all higher order quantum electrodynamical corrections to the energy levels of muonic atoms are presented in tabular and graphical form. These corrections include the vacuum polarization corrections caused by emission and reabsorption of virtual electron pairs to all orders, including ''double-bubble'' and ''cracked-egg'' diagrams. An estimate of the Delbruecke scattering-type correction is presented. The Lamb-shift (second- and fourth-order vertex) corrections have been calculated including the correction for the anomalous magnetic moment of the muon. The relativistic nuclear motion (or recoil) correction as well as the correction caused by the screening of the atomic electrons is presented in graphs. For the sake of completeness a graph of the nuclear polarization as computed on the basis of Chen's approach has been included. All calculations were made with a two-parameter Fermi distribution of the nuclear charge density. 7 figures, 23 references. (auth)
Date: August 1, 1975
Creator: Rinker, G.A. Jr. & Steffen, R.M.
Partner: UNT Libraries Government Documents Department

Quantum electrodynamics with the spear magnetic detector

Description: One makes a study of quantum electrodynamic processes which are present at the SPEAR colliding beam magnetic detector. We begin by describing the experiment performed by the SLAC-LBL collaboration and the results concerning the strong interaction. Then the interactions e$sup +$e$sup -$ $Yields$ e$sup +$e$sup -$ and e$sup +$e$sup -$ $Yields$ $mu$$sup +$$mu$$sup -$ are considered along with their third-order radiative corrections. These events, previously used to determine new limits for cutoff parameters in QED breakdown models, are further studied to show that the full distribution in coplanarity angle fits the theoretical prediction well. The major focus is on the fourth order two-photon process, e$sup +$e$sup -$ $Yields$ e$sup +$e$sup -$A$sup +$A$sup -$, which only recently has been realized to be significant in such experiments. Cross sections are derived and calculated exactly for this process and the results compared to a Weizacker-Williams equivalent photon calculation. The two-photon data are then isolated and fit to the calculation. A special experiment was done where the small-angle scattered electron or positron is ''tagged'' along with particles in the main detector. Cross sections and coplanarity distributions are measured and compared to calculation. Through these studies, one feels confident that one understand the nature of the two-photon process in the detector. One further explores the hadronic physics of the two-photon process, e$sup +$e$sup -$ $Yields$ e$sup +$e$sup -$ hadrons, measuring pion cross sections, searching for resonances, and discussing future experiments. (auth)
Date: September 1, 1975
Creator: Zipse, J.E.
Partner: UNT Libraries Government Documents Department