Influence of an intense pulsed electromagnetic field on nonresonant scattering of a photon by an electron for the nonrelativistic energy

The theory of nonresonant scattering of a photon by an electron in the field of an intense pulsed light wave is developed. The approximation when a pulse width is considerably greater than the characteristic time of wave oscillation is considered. The nonresonant kinematic region is determined. The general relativistic expression for the nonresonant cross-section is derived for the range of the external field intensities if η ₀ ? 1, η₀ ² ? 1 (see Eq. (12)) is valid. The obtained differential cross-section of the process has form of a sum over partial differential cross-sections. Each of them corresponds to the process with emission (absorption) of a certain number of wave photons. It is shown, that for nonrelativistic energy the cross-section summed over all possible partial processes differs considerably from the cross-section of Compton scattering if the external field is absent and may exceed the latter over than 200%.     

Resonant scattering of an electron by a muon in the field of light wave

In the frame of the Born approximation we theoretically investigate resonant scattering of an electron by a muon in the field of elliptically polarized electromagnetic wave in the general relativistic case. It is studied kinematics of a scattering of an electron in resonant region. It is derived the expressions for the amplitude and the cross-section of the resonant scattering of an electron by a muon when the invariant intensity parameter of the laser field is small (η_e ≪1). It is demonstrated that the resonant cross-section of a scattering may be several orders of magnitude higher than the cross-section of a scattering in the absence of the external field.     

Quantum electrodynamics resonances in a pulsed laser field

This review contains theoretical study of resonant quantum electrodynamics processes in a pulsed laser field. The approximation is examined when the pulse width is considerably greater than the characteristic time of wave oscillations. The lepton??s interaction with the Coulomb potential of a nucleus and each other is considered in the Born approximation. It is demonstrated that the resonant differential cross section of a process in a pulsed light fields may considerably exceed the corresponding cross section in an absence of a laser field. Results obtained may be experimentally verified by the scientific facilities at the SLAC National Accelerator Laboratory and FAIR (Facility for Antiproton and Ion Research, Darmstadt, Germany) project.     

Nonresonant spontaneous bremsstrahlung by a relativistic electron scattered by a nucleus in the field of pulsed light wave

This paper presents theoretical study of nonresonant spontaneous bremsstrahlung by an electron scattered by a nucleus in the field of the pulsed light wave. The electron interaction with a Coulomb potential of a nucleus is considered in the first order of perturbation theory (the Born approximation), and the interaction with an external pulsed field is taken into account accurately. The approximation is examined when pulsewidth is considerably greater than the characteristic time of wave oscillations. The obtained differential cross-section of the process has form of a sum over partial differential cross-sections. Each of them corresponds to processes with emission (absorption) of certain number of wave photons. It is shown, that for spontaneous bremsstrahlung by an electron scattered by a nucleus in the field of a pulsed light wave the distribution of a stimulated emission-absorption probability is determined by the average value of corresponding probabilities in the case monochromatic wave.     

Resonant electron-positron pair photoproduction on a nucleus in a pulsed light field

The resonant photoproduction of an electron-positron pair on a nucleus in the field of a pulsed light wave is studied theoretically. The approximation where the electromagnetic pulse duration is much longer than the characteristic time of wave oscillations is considered. The interaction of the electron and positron with the Coulomb potential of the nucleus is considered in the Born approximation. An analytical expression for the resonant differential cross section is derived for the range of moderately strong external fields. This cross section contains a resonant peak whose height and width are determined by the external pulsed wave characteristics. The resonant cross section for pair photoproduction on a nucleus in a pulsed laser field can exceed the corresponding cross section for pair photoproduction on a nucleus in the absence of an external field by an order of magnitude.     

Resonance of exchange amplitude of Compton effect in the circularly polarized laser field

We present, for general relativistic case, a theoretical study of resonance of exchange amplitude when a photon is scattered by an electron in the field of a circularly polarized wave. Resonances are related to a virtual intermediate particle that falls within the mass shell. We find conditions when resonances occur in exchange amplitude. We derive the expressions for the resonant amplitudes and the differential cross-sections when the invariant intensity parameter of the laser field is small (η≪1) and the interference of direct and exchange amplitudes is absent. It is demonstrated that the resonant cross-section of scattering may be several orders of magnitude higher than the cross-section of Compton effect in the absence of the external field.     

Nonresonant photocreation of electron-positron pair on a nucleus in the field of a pulsed light wave

The nonresonant Coulomb photocreation of electron-positron pair on a nucleus in the field of a pulsed light wave is theoretically investigated. The approximation is examined when pulsewidth is considerably greater than the characteristic time of wave oscillations. The interaction of an electron and a positron with a Coulomb potential of a nucleus is considered in the first order of perturbation theory (the Born approximation). An analytic expression for the nonresonant differential cross section was obtained for the range of moderately strong fields in the case relativistic and nonrelativistic energies. It is shown, that the nonresonant cross section of Coulomb photocreation of nonrelativistic pair in the field of a pulsed light wave is two times larger than the cross section of Coulomb photocreation in the absence of an external field.     

Electroweak lepton decay in the external field of a planar electromagnetic wave with circular polarization

The process of lepton decay into a W-boson and a neutrino and decay of a W-boson into a lepton and antineutrino in the field of a plane electromagnetic wave are considered within the framework of the Weinberg-Salam model. Exact expressions in terms of the external field are obtained for the probabilities of these processes and special cases are considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 30–34, May, 1987.     

Electric field effect on the Raman scattering of a hydrogenic impurity in spherical quantum dot

Using the perturbation method and the effective mass approximation, we studied the combined effects of impurity and external electric field on Raman scattering in a spherical quantum dot with a parabolic potential. Based on the computed energies and wave functions, the differential cross-section involved in this process is investigated, and the selection rules are also calculated. Our results suggest that the scattering intensity is strongly affected by the impurity and external electric field considered in this work.     

Resonance Compton scattering in an external magnetic field

The scattering of a photon by an electron in an external magnetic field under resonant conditions, when the photon energy is close to the splittings between the Landau levels, is investigated. Formulas are obtained for the cross section of the process taking account of the polarization of the electron. For external fields ～10¹² G the resonant Compton cross section is several orders of magnitude greater than the Thompson cross section, and the width of the resonance is tens of electron volts.     

Nonresonant quantum electrodynamics processes in a pulsed laser field

This review contains theoretical study of nonresonant quantum electrodynamics processes of the first and second orders in the fine-structure constant in a pulsed laser field. The approximation is examined when the pulse width is considerably greater than the characteristic time of wave oscillations. It was demonstrated that for nonrelativistic particle energy the differential cross section of a process in a pulsed light fields may considerably difference from the corresponding cross section in an absence of a laser field. Results obtained may be experimentally verified by the scientific facilities at the SLAC National Accelerator Laboratory and FAIR (Facility for Antiproton and Ion Research, Darmstadt, Germany) project.     

One-photon annihilation of an electron-positron pair in the field of pulsed circularly polarized light wave

The one-photon annihilation of an electron-positron pair in the pulsed light field is investigated theoretically. The pulsed laser field is described by the plane circularly polarized electromagnetic wave with the envelope function. The analytical expressions for an amplitude and probability of the studied process are derived. The conditions for an observation of the one-photon annihilation the pulsed light field are ascertained. It is demonstrated, that the region of numerical values of the initial particles parameters within which the one-photon annihilation in the pulsed light field may be possibly realized is significantly broader in comparison with the monochromatic wave case. Within the observation domain the probability of one-photon annihilation process in the pulsed light field essentially exceeds the correspondent one the external field absence, except the points with the strong suppression of the probability which is the result of an interference of the amplitude’s parts; the last ones correspond to the contributions of the front and posterior segments of the pulse.     

Resonant scattering of photon by electron in the presence of the pulsed laser field

The scattering of photon by electron in the presence of the field of the low-intensity circularly-polarized pulsed laser wave is analyzed at a laser pulse duration that is significantly greater than the characteristic oscillation time. The conditions for the resonance process in which the intermediate particle is located in the vicinity of the mass surface are determined. The existence of three resonance ranges is demonstrated. The first one corresponds to the resonance of direct diagram, and two ranges correspond to the resonance of exchange diagram via electron and positron intermediate states. The conditions under which only the resonance of the direct diagram takes place are determined, and the probability of such process is calculated. It is demonstrated that the resonance probability can be significantly greater than the probability of the Compton effect in the absence of the external field.     

Polarisation observables in lepton-antilepton-to-proton-antiproton reactions including lepton mass

General expressions, including the lepton mass, for the spin-averaged differential cross-section for the annihilation reaction lepton-antilepton to proton-antiproton are given, as well as general formulae for the single- and double-spin asymmetries in the centre-of-mass frame. In particular, we discuss the single-spin asymmetry, normal to the scattering plane, which measures the relative phase difference between nucleon electromagnetic form factors G_E and G_M. Recent experimental investigations of these form factors in the space- and time-like region are reviewed. It is thought that measurements of the phase of these form factors will provide fundamental information on the internal nucleon structure. The phases between G_E and G_M are accessible through polarisation observables measured in the antiproton-proton-to-lepton-antilepton reaction, or in its time-reversed process.     

One phonon-assisted electron Raman scattering in a wurtzite cylindrical quantum well wire

We report the electron resonant Raman scattering (ERRS) process related to the longitudinal optical (LO), interface optical (IO) and quasi-confined (QC) phonons in a cylindrical GaN-AlN quantum well wire (QWW). We present the differential cross-section (DCS) and study the selection rules. Results reveal that the emitted photon frequency decreases with increasing the radius because of the size-selective Raman scattering effect and the built-in electric field. The contribution to the DCS mainly stems from the GaN-type LO (LO1), QC and IO phonons when the wire is thin, but the LO1 and QC phonons are dominant for the thick wire.     

Mass operator for a charged lepton in the Weinberg-Salam theory in a constant external field

An expression is found for the propagator of a charged W-boson in the presence of an arbitrary flat-wave electromagnetic field. The W-boson contribution to the mass operator of a charged lepton moving in a constant external electromagnetic field is computed in the second order of perturbation theory in the Weinberg-Salam model. A closed expression is obtained for the vacuum W-boson contribution (independent of the external field) to the anomalous magnetic moment of a charged lepton.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 55–57, December, 1985.     

Resonance radiation in electromagnetic wave scattering by a fast electron in the external magnetic field

The resonance radiation in Compton scattering of an electromagnetic wave by a fast relativistic electron moving in a given magnetic field is investigated with allowance for deceleration by the radiation. A general expression for the electric field of an arbitrarily polarized scattered wave is derived within the framework of small-perturbation theory. It is shown that the resonance peak in the scattering cross-section is caused by the small radiation friction. The dependence of the resonance line width on the characteristic parameters of the problem is examined. The scattering of a given polarized wave is considered, and the degree of linear polarization of the radiated wave under resonance is determined.Institute of Radiophysics and Electronics, Armenian Academy of Sciences, Erevan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 10, pp. 1001–1011, October, 1995.     

Universal higher order singlet QED corrections to unpolarized lepton scattering

We calculate the universal flavor singlet radiative QED corrections to unpolarized lepton scattering applicable to general differential scattering cross sections, involving charged fermions or photons in the initial or final states. The radiators are derived to O((αln(Q²/m_f ²))⁵) in analytic form. Numerical illustrations are given.     

Intense laser field effects on the electron Raman scattering in a strained InGaN/GaN quantum well

The differential cross-section for an intersubband electron Raman scattering process in a strained InGaN/GaN quantum well in the presence of an intense laser field is studied. In the effective-mass approximation, the electronic structure is calculated by taking into account the effects of spontaneous and piezoelectric polarization fields on the confinement potential. Effects of laser field strength, indium composition and the well width on the differential cross-section of the strained quantum well are investigated. Results show that the position and the magnitude of the peaks of emission spectra considerably depend on the laser field strength as well as structural parameters.     

Contribution of Higgs bosons to the elastic scattering amplitude of a lepton in a flat wave field

The contribution of pseudoscalar particles (⁰-mesons and Higgs bosons) to the elastic scattering amplitude of a lepton in the field of a flat elliptically polarized electromagnetic wave is computed by using dispersion relations. The polarization effects are considered. By a limit transition, the contribution of pseudoscalar particles to the amplitude is found in a constant crossed field.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 85–90, January, 1991.