Resonant production of electron-positron pairs by a hard gamma-ray on a nucleus in an external electromagnetic field

2020 ◽  
Vol 35 (03) ◽  
pp. 2040025 ◽  
Author(s):  
Nikita R. Larin ◽  
Victor V. Dubov ◽  
Sergei P. Roshchupkin
Keyword(s):  
Electromagnetic Field ◽  
Differential Cross Section ◽  
External Field ◽  
Cross Section ◽  
Differential Cross ◽  
Gamma Ray ◽  
Structure Constant ◽  
External Electromagnetic Field ◽  
Electron Positron ◽  
Resonant Production

The resonant production of electron-positron pairs by a hard gamma-ray on nucleus in an external electromagnetic field is studied theoretically. The main property of this process is that the initial process of the second order in the fine structure constant in an external field effectively splits into two successive processes of the first order due to the fact that in resonant conditions intermediate virtual electron (positron) becomes a real particle. One of these processes is a single-photoproduction of electron-positron pair in a laser field (laser-stimulated Breit-Wheeler process) another is a laser-assisted scattering of electron (positron) on nucleus (laser-assisted Mott scattering). It is shown that the resonances are possible only for the energies of the initial hard gamma-ray more than the characteristic threshold energy. Resonant differential cross section of this process is obtained. It is shown that the resonant differential cross section can significantly exceed the corresponding cross section without an external field. The obtained results may be experimentally verified using the facilities of pulsed laser radiation (SLAC, FAIR, XFEL, ELI, XCELS).

Resonant Breit-Wheeler process in an external electromagnetic field

2020 ◽  
Vol 35 (03) ◽  
pp. 2040027 ◽  
Author(s):  
Alexander A. Pustyntsev ◽  
Victor V. Dubov ◽  
Sergei P. Roshchupkin
Keyword(s):  
Differential Cross Section ◽  
External Field ◽  
Pair Production ◽  
Cross Section ◽  
Differential Cross ◽  
Single Photon ◽  
Gamma Quantum ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Electron Positron

The contemporary research scrutinizes the resonant Breit-Wheeler process in the field of a plane monochromatic electromagnetic wave. Implementing the weak external field condition the processes of electron-positron pair production advances pre-eminently with participation of restrictively two field photons. Thus, within the resonant state the represented process effectively splits into two first-order processes with respect to the fine-structure constant. In details, the effect indicates the single photon pair production with consequent absorption of gamma quantum by an electron (positron) in the field of the wave. We analyze the resonance kinematics precisely. The study determines specific regions in which the interference of resonant amplitudes is absent. Additionally, the computation obtains a resonant differential cross section for the described areas. The corresponding resonant differential cross section significantly exceeds the correlating Breit-Wheeler cross-section without an external field. Various scientific facilities of pulsed laser radiation may experimentally verify the results of these calculations (SLAC, FAIR, XFEL, ELI, XCELS).

Bremsstrahlung linear polarization

1989 ◽  
Vol 67 (6) ◽  
pp. 545-561
Author(s):  
W. Del Bianco ◽  
M. Carignan
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Linear Polarization ◽  
Differential Cross ◽  
Born Approximation ◽  
Gamma Ray ◽  
High Energy ◽  
Scattered Electron ◽  
Triple Differential Cross Section

The dependence of the bremsstrahlung perpendicular and parallel triple differential cross sections and the linear polarization on the angles and energies of the incident and scattered electron and of the emitted gamma-ray has been studied in the high-energy small-angle hypothesis. The expression used for the bremsstrahlung triple differential cross section is valid in the Born approximation and for an unscreened Coulomb potential of the nucleus.

Vector meson production in electron positron annihilation process

2021 ◽  
pp. 2150120
Author(s):  
Weihua Yang ◽  
Fei Huang
Keyword(s):  
Differential Cross Section ◽  
Vector Meson ◽  
Positron Annihilation ◽  
Cross Section ◽  
Differential Cross ◽  
High Energy ◽  
Annihilation Process ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Fragmentation Functions

When tunneling events induced by nontrivial configurations of the quantum chromodynamics gauge fields are taken into consideration, parity violating quantities emerge. Based on this consideration, parity-odd fragmentation functions can be introduced in the high energy reactions. In this paper, we calculate the differential cross-section in terms of both the parity-even and parity-odd fragmentation functions in semi-inclusive electron positron annihilation process. Semi-inclusive implies that not only a vector meson in one jet but also the back-to-back jet is measured in this reaction. According to the differential cross-section, we further calculate the azimuthal asymmetries and hadron polarizations in terms of fragmentation functions. A method of measuring the parity violating effects in the semi-inclusive annihilation process is suggested.

Resonant annihilation and production of high-energy electron-positron pairs in an external electromagnetic field

2020 ◽  
Vol 35 (03) ◽  
pp. 2040023 ◽  
Author(s):  
D. V. Doroshenko ◽  
V. V. Dubov ◽  
S. P. Roshchupkin
Keyword(s):  
Electromagnetic Field ◽  
Cross Section ◽  
Threshold Energy ◽  
External Electromagnetic Field ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Annihilation Channel ◽  
Positron Scattering ◽  
Electron Positron

A resonant process of annihilation and production of high-energy electron-positron pairs in an external electromagnetic field is studied theoretically. This process is the annihilation channel of an electron-positron scattering. It is shown that the resonance in an external electromagnetic field is possible only when the certain combination of electron and positron initial energies is more than threshold energy. Also, the angle between initial electron and initial positron momenta directions must be small and satisfy the resonant conditions. This angle is determined by the high-energy of the initial pair and the threshold energy. An emerging electron-positron pair also flies out in a narrow cone along the direction of the initial pair and must be ultrarelativistic. For each fixed angle, energies of the final electron and positron can take from one to two values. It is shown that the resonant differential cross section can significantly exceed the corresponding Bhabha cross section without an external field.

scholarly journals Fundamental physical features of resonant spontaneous bremsstrahlung radiation of ultrarelativistic electrons on nuclei in strong laser fields

2022 ◽  
Vol 24 (1) ◽  
pp. 013020
Author(s):  
S P Roshchupkin ◽  
A V Dubov ◽  
V V Dubov ◽  
S S Starodub
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Gamma Quantum ◽  
Structure Constant ◽  
Angular Width ◽  
Bremsstrahlung Radiation ◽  
Laser Fields ◽  
Strong Laser ◽  
Strong Laser Fields

Abstract Theoretically predicted fundamental features in the process of resonant spontaneous bremsstrahlung radiation during the scattering of ultrarelativistic electrons with energies of the order ∼ 100 GeV by the nuclei in strong laser fields with intensities up to I ∼ 1024 W cm−2. Under resonant conditions, an intermediate electron in the wave field enters the mass shell. As a result, the initial second-order process by the fine structure constant is effectively reduced to two first-order processes: laser-stimulated Compton effect and laser-assisted Mott process. The resonant kinematics for two reaction channels (A and B) is studied in detail. An analytical resonant differential cross-section with simultaneous registration of the frequency and the outgoing angle of a spontaneous gamma-quantum for channels A and B is obtained. The resonant differential cross section takes the largest value with a small number of absorbed laser photons. In this case, the resonant cross-section is determined by one parameter, depending on the small transmitted momenta, as well as the resonance width. In strong fields, spontaneous gamma quanta of small energies are most likely to be emitted compared to the energy of the initial electrons. At the same time, the angular width of the radiation of such gamma quanta is the largest. With an increase in the number of absorbed laser photons, the resonant cross-section decreases quite quickly, and the resonant frequency of spontaneous gamma quanta increases. It is shown that the resonant differential cross-section has the largest value in the region of average laser fields (I ∼ 1018 W cm−2) and can be of the order of ∼ 1 0 19 in units Z 2 α r e 2 . With an increase in the intensity of the laser wave, the value of the resonant differential cross-section R r e s max decreases and for the intensity I ∼ 1024 W cm−2 is R r e s max ≲ 1 0 7 in units Z 2 α r e 2 . The obtained results reveal new features of spontaneous emission of ultrarelativistic electrons on nuclei in strong laser fields and can be tested at international laser installations.

scholarly journals The Resonant Effect of an Annihilation Channel in the Interaction of the Ultrarelativistic Electron and Positron in the Field of an X-ray Pulsar

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 137 ◽  
Author(s):  
Dmitriy V. Doroshenko ◽  
Sergei P. Roshchupkin ◽  
Victor V. Dubov
Keyword(s):  
Fine Structure ◽  
External Field ◽  
Cross Section ◽  
Single Photon ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
X Ray ◽  
Electron Positron ◽  
Resonant Effect ◽  
Electron Positron Pair

We investigated the effects that occur during the circulation of ultrarelativistic electrons and positrons in the field of an X-ray pulsar. A resonant process in annihilation and the subsequent production of the electron–positron pairs were studied theoretically. Under the resonance, the second-order process in an original fine-structure constant process effectively decays to two first order processes of the fine-structure constant: single-photon annihilation of the electron–positron pair stimulated by the external field, and the Breit–Wheeler process (single-photon birth of the electron–positron pair) stimulated by the external field. We show that resonance has a threshold energy for a certain combinational energy of the initial electron and positron. Furthermore, there is a definite small angle between initial ultrarelativistic particles’ momenta, in which resonance takes place. Initial and final electron–positron pairs fly in a narrow cone. We noticed that electron (positron) emission angle defines the energy of the final pair. We show that the resonant cross-section in the field of the X-ray pulsar may significantly exceed the corresponding cross-section without the field (Bhabha cross-section).

On Energy and Angular Distributions of Electrons in Triplet Production

1985 ◽  
Vol 40 (12) ◽  
pp. 1182-1188 ◽  
Author(s):  
Eberhard Haug
Keyword(s):  
Perturbation Theory ◽  
Differential Cross Section ◽  
Cross Section ◽  
Momentum Distribution ◽  
Differential Cross ◽  
Electron Pair ◽  
Angular Distributions ◽  
Free Electrons ◽  
Electron Positron ◽  
Energy And Angular Distributions

The differential cross section of electron pair production in the field of free electrons (triplet production) is derived from the cross section for electron-positron bremsstrahlung exact to lowest order of perturbation theory. It is used to compute energy and angular distributions of the outcoming electrons. The results are compared with previous calculations. In particular, the accuracy of the momentum distribution according to the Borsellino approximation is discussed.

scholarly journals The Resonant Bremsstrahlung of Ultrarelativistic Electrons on a Nucleus with Radiation of Hard Gamma-Quanta in the Presence of a Pulsed Field of the X-ray Pulsar

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 143
Author(s):  
Alexander Dubov ◽  
Victor V. Dubov ◽  
Sergei P. Roshchupkin
Keyword(s):  
Electromagnetic Field ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Gamma Quantum ◽  
Structure Constant ◽  
High Energy ◽  
Fine Structure Constant ◽  
Order Effects ◽  
X Ray

The investigation scrutinizes the circulation of the large-scaled fluxes of ultrarelativistic electrons near the neutron stars. This work focuses on the effects that occur during the adjustment of the strong electromagnetic field near the X-ray pulsars. Particularly, this study analyzes the resonant high-energy spontaneous bremsstrahlung of ultrarelativistic electrons in the pulsed fields of a nucleus and X-ray pulsar. Specific attention is given to the pulsed character of the field model. Under the resonant conditions the intermediate virtual electron within the electromagnetic field transforms into a real particle. As a result, the initial second-order process with accordance to the fine structure constant effectively splits into two first-order effects: the stimulated Compton process and the field-assisted scattering of an electron on a nucleus. In this research we obtain the resonant differential cross-sections with registration of frequency and radiation angle of a hard gamma-quantum. To summarize, the resonant differential cross-section of the effect within the external pulsed electromagnetic field of X-ray pulsar significantly exceeds the corresponding cross-section without an external field.

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