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[en] Electron inelastic scattering has been investigated in the region of the threshold of electron quasielastic scattering and meson electroproduction. It is shown that inelastic scattering of electrons with an energy above 1 GeV cannot be explained by a sum of the electron quasielastic scattering cross sections and pion electroproduction on separate nucleons interpreted in the impulse approximation. A most noticeable difference from the impulse approximation is observed in the region of the cross section minimum between peaks of quasielastic scattering. To explain the difference a contribution of the triangular diagram is considered which corresponds to reabsorption of a produced pion. It is shown that the account of pion absorption in the calculation may result in a satisfactory agreement of the calculation and an experiment

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[en] The review of the latest results of deuteron electrodisintegration into a back hemisphere, which have been obtained by the Kharkov Physico-Technical Institute, is presented for the International symposium on photon and lepton interaction at high energies (FRG, Hamburg, 27-31 of July, 1987). Spectra measured from the electrodisintegration threshold to the first pion-nucleon resonance start at 127 deg angle and 538...779 MeV energies are given. The square values of the four momentum transferred near the electrodisintegration threshold are within interval q²=0.63...1.16 GeV². A form of nuclear scaling (z-scaling), which operates in the relativistic region and describes both electrical and magnetic scattering unlike the known y-scaling, has been found. A magnetic structural function has been determined in the region from the electrodisintegration threshold to the maximum of the quasielestic scattering peak

[en] Presented is a review of the experimental data on the electron inelastic scattering on light nuclei (sup(6,7)Li, sup(10,11)B, ¹²C) in the vicinity of the first pion-nucleon resonance. In the region of the (33)-resonance maximum, breaking of the momentum approximation has been shown not to exceed 15-20%. In the region of the cross section minimum between the peaks of quasi-elastic scattering and the (33)-resonance a considerable contribution comes from two-particle absorption of a virtual photon. The calculations performed in the phase volume approximation satisfactorily agree with the experimental data on a ⁷Li nucleus at the pion absorption probability equal to 0.7. A significant value of the pion absorption probability and the character of cross section dependence on the energy transfer do not exclude a possibility of arising a bound state of a pion and two nucleons

[en] An electron shower detector with a converter and charged particle counters is described. To increase the authenticity of electron identification in the 200-1000 MeV energy range, two charged particle counters connected to the coincidence circuit are placed behind the converter. The counters are situated in different parts of secondary particle escape sphere relative to the plane through the trajectory of detected electrons passing through the converter center. Due to the fact that a shower non-producting particle can not pass through two counters the logic pulse at the circuit output does not occur. When an electron passes through a lead plate a shower appears the particles of which will pass through both counters of charged particles. In this case a logic pulse appears at the output of the coincidence circuit that proves the pass of the electron

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[en] A current status of the experimental studies of the threshold electroproduction of pions on nucleons is reviewed. The data on separation of the transverse and longitudinal components to the threshold slope of the cross section are emphasized as a main achievement of the recent years. The axial-vector form factor of the nucleon has been determined from the transverse component and proved to have weak model dependence. The axial mass in the dipole fit is found to equal (0.97+-0.06) GeV. An electromagnetic pion radius < rsub(π)sup(2)> 1/2(0.45+-0.10) F, has been determined from the longitudinal component. Dependences of the threshold slopes of cross sections on the polarization of a virtual photon and the results for determination of the transverse and longitudinal components for the sum of the π⁰ and π⁺ production channels are presented in a graphical form. Comparison of the results of the different methods used demonstrates their consistency

[en] Electron scattering on nuclei in the region of electroproduction of a Δsub(1236) isobar has been investigated. A realistic model of pion electroproduction on nuclei is formulated in the pulse approximation. Factorization of a polynomial and a resonance term serves as a cross section on nucleons. Their coefficients are determined from experimental data. The analytical expression obtained for the sum of cross sections on nucleons convolves with the nucleus wave function, the momentum distribution in the shell model with an oscillatory potential being used as the wave function. The formulas presented allow to repeat the calculations and investigate the applicability of the pulse approximation

No abstract available