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Numerical results for the alpha /sup 3/ differential cross section for e/sup +/e/sup -/ yields e/sup +/e/sup -/ are presented for the case of e/sup +/ e/su p -/ colliding beams. Special care is given to the hard photon corrections. Acoplanarity distributions for e/sup +/e/sup -/ yields e/sup +/e/sup -/ gamma are also presented. Attention is drawn to experimental conditions which require the calculation of still higher order corrections. (auth)

We report measurements of e+e−→e+e−, e+e−→γγ, and e+e−→μ+μ− at angles close to 90°, relative to Bhabha scattering at 3.7°, at a center-of-mass energy equal to 5.2 GeV. The results are found to be consistent with the predictions of quantum electro-dynamics.

This review is a survey of three main topics in quantum electrodynamics; fundamental bound system; anomalous magnetic moments and high energy experiments. The emphasis lies particularly in recent developments concerning the electron and muon anomalous magnetic moments. (844 refs).

The electromagnetic interaction of the Bhabha field with spin 32 and two-mass states has been discussed and the quantization has been performed. It is shown using the Bhabha theory that ψ(x) = ψ(x|σ) holds even for spin 32 field.

The absolute cross-section σ of Bhabha scattering e + e − → e + e − has been measured at a total center of mass energy of 1020 MeV to test quantum electrodynamics. The result is compared to the theoretical cross-section modified by adding a positive or a negative metric pole to the photon propagator: 1 q 2 → 1 q 2 ± 1 (q 2 −Λ 2 ) . A lower limit of Λ is obtained: Λ > 3.8 GeV (positive metric) or Λ > 2.0 GeV (negative metric).

The scattering of positons by negatons in the energy range 1.52 MeV to 2.62 MeV was investigated experimentally. A beta-ray spectrometer was employed and a coincident counting technique was used to detect the scattered particles. The results obtained verify the Bhabha formula for positon-negaton scattering which is the generally accepted theory.

We present the analysis of 5164 wide angle Bhabha events collected at several c.m. energies between 1.4 and 2.4 GeV using the Frascati e + −e − storage ring, ADONE. The results are in agreement with the predictions of quantum electrodynamics within the experimental errors (±10%).

The Bhabha equation which describes a particle having multi-mass and spin states with maximum spin S , integer or half an odd integer, is considered. In the presence of interactions e.g. the electromagnetic interaction introduced through minimal coupling, it is found to yield the same (anti-) commutators as in the case of a free field. Also the propagation of an interacting field is causal. This shows the absence of inconsistencies of the type, pointed out by Johnson and Sudarshan. Finally the applicability of the methods of quantisation is discussed.

A method that permits an absolute measurement of the polarization of positrons from meson ( mu /sup +/) decay without slowing down the positrons is described. The method uses positron-electron (Bhabha) scattering in magnetized iron. The magnetized iron provides a target of polarized electrons, and the positron polarization can be evaluated from the scattering asymmetry. (C.E.S.)

Since it is very likely that the contributions (if there are any at all) of weakly interacting neutral vector bosons to ordinary Bhabha scattering can be increased sufficiently with respect to the common photon process, the weak coupling constant might be measured with great accuracy in these processes. Therefore it is necessary to know the amount of the radiative corrections to this process, which is calculated in this paper.

The longitudinal polarization of positrone from the pure Fermi transition of O/sup 14/ was studied by the method of Bhabha scattering. A prismstic beta -ray spectrometer selected 1.0Mev positrons which then were focused by a solenoidal magnetic lens on a Supermendur foil magnetized by the lens. Scattered positrons and recoil electrons were detected in fast coincidence. The scattering asymmetry observed upon reversal of the lens magnetic field was observed, and the corresponding positron longitudinal polarization calculated. (auth)

The relative weight at different energies and angles of the radiative corrections due to the various terms (photon self-energy, vertex parts, two- photon exchange) is discussed using numerical data, and also the angular distributions in the c.m.s. and in the l.s. for both Moeller and Bhabha processes are given. (N.W.R.)

Die Polarisation von Elektronen und Positronen kann durch Streuung an ausgerichteten Elektronen bestimmt werden. Dazu ist die Kenntnis des Streuquerschnitts notig. Dieser war jedoch nur fur den Spezialf all paralleler bzw. antiparalleler Orientierung der Spins gegeneinander bekannt, der sich experimentell nicht verwirklichen last. Der differentielle Wirkungsquerschnitt fur die Streuung longitudinal polarisierter Elektronen und Positronen an ruhenden beliebig polarisierten Elektronen wird explizit angegeben.

The study of positron–electron scattering is made using a Wilson cloud chamber to check the presence of Bhabha exchange effects. The observed scattering cross section is more than the value calculated from Moller's theory of positron–electron scattering, where only the Coulomb interaction between the particles is considered. However, the experimental results are in good agreement with the theory if the exchange effects suggested by Bhabha are also included.

In an experiment performed at Adone, the Frascati 2×1.5 GeV electron-positron storage ring, the e+e− wide-angle elastic-scattering process was investigated. In this paper we present the analysis of approximately 1700 e+e− Bhabha scattering events collected at several energies of the incident electron and positron beams between 0.8 and 1.0 GeV; this corresponds in our experimental apparatus to an averaged momentum transfer to the virtual spacelike photon ranging within ∼(1.0÷1.7) (GeV/c)2. In the energy range explored the experimental data show a slope and an absolute value in agreement with the predictions of quantum electrodynamics to within the experimental errors of ∼10%.

Electron-positron elastic scattering has been investigated experimentally using colliding beams of total energy ranging from 1.4 to 2.4 GeV. The results, based on the analysis of 3255 wide angle scattering events, agree with the predictions of quantum electrodynamics up to the highest space-like momentum-transfers involved.

Die Lie-Algebra der Bhabhaschen Wellengleichung liefert innere Transformationen des Feldes nicht nur fur die spezielle, sondern fur die volle Lorentz-Gruppe. Fur die Paritat (ebenso wie fur alle anderen Achsenspiegelungen desR4) ergeben sich dabei fur Fermionen nur die Eigenwerte ±i der imaginaren Paritatsklasse.