Faculty of Physics - University of Bucharest

UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-23 18:34

HOME CONFERENCES SEARCH LOGIN NEW USER IMAGES

Conference: Bucharest University Faculty of Physics 2023 Meeting

Section: Nuclear and Elementary Particles Physics

Title:

Studies of Strong Field QED Processes at ELI-NP

Authors:

Mircea PENTIA, Chivuta BADITA, Dana DUMITRIU, Amilcar IONESCU, Horia PETRASCU

Affiliation:

Horia Hulubei - National Institute for Physics and Nuclear Engineering

E-mail

pentia@nipne.ro

Keywords:

Strong Field QED, Multi-photon interactions, Feynman amplitudes for QED processes, Schwinger effect, Breit-Wheeler process, Bethe–Heitler process, ELI-NP.

Abstract:

In high energy particle physics the production of massive particles is a common local process. On the other hand the low energy laser photon – electron interaction has a larger range (λc - electron Compton wavelength) that allows a multi-photon interaction with a single electron. This can produce matter by transforming virtual e+e- pairs of the physical vacuum into real ones. Particle production from the EM field, one of the amazing predictions of QED, is possible exploiting the physical vacuum properties in some settings: - an intense static electric field: Schwinger effect [1-6]. - a photon field: Breit – Wheeler process [7]. - a combination of the two: Bethe – Heitler process [8]. In the regime of Strong Field QED (SFQED) the photon-electron interactions (charge-field coupling parameter ξ>>1) are treated non-perturbatively. The diagrams with a given order in α (fine-structure constant), depend on all terms in ξ expansion. Until now the Schwinger limit ~1018 V/m of static electric field, has not been reached experimentally. But in the context of HPLS (High Power Laser System) [9,10] combining high intense electric field interacting with relativistic electrons, the particle production by Schwinger effect can be observed. In the ELI-NP environment, the e+e- pairs production can be considered by two types of processes: Breit - Wheeler: γR + n γL --> e+ + e- or Bethe – Heitler: γR + γV --> e+ + e- The GeV γR real photons can be obtained using laser wakefield accelerated electrons by "bremsstrahlung" or "inverse Compton scattering". The study of SFQED processes involves the cross sections evaluation with Feynman diagrams and constructing characteristic distributions on the available phase space. A specific setup at ELI-NP can be prepared.

References:

[1] F. Sauter, “Über das Verhalten eines Elektrons im homogenen elektrischen Feld nach der relativistischen Theorie Diracs“ Z. Phys. 69 (1931) 742;

[2] W. Heisenberg, H. Euler, „Folgerungen aus der Diracschen Theorie des Positrons“ Z. Phys. 98 (1936) 714;

[3] J. S. Schwinger, „On Gauge Invariance and Vacuum Polarization”, Phys. Rev. 82, 664 (1951).

[4] H. R. Reiss, “Absorption of light by light”, J. Math. Phys. 3, 59 (1962).

[5] N. B. Narozhny, A. I. Nikishov, and V. I. Ritus, “Quantum Processes in the Field of a Circularly Polarized Electromagnetic Wave”, Sov. Phys. JETP 20, 622 (1965).

[6] V. I. Ritus, “Quantum effects of the interaction of elementary particles with an intense electromagnetic field”, J. Sov. Laser Res. 6, 497 (1985).

[7] G. Breit and J.A. Wheeler, “Collision of Two Light Quanta”, Phys. Rev. 46, 1087 (1934).

[8] H.A. Bethe and W. Heitler, “On the stopping of fast particles and on the creation of positive electrons”, Proc. Roy. Soc. A146, 83 (1934).

[9] I. Turcu et al, “High field physics and QED experiments at ELI-NP”, Rom. Rep. Phys. 68, Supplement, S145 (2016).

[10] I. Turcu et al., “Quantum electrodynamics experiments with colliding petawatt laser pulses”, High Power Laser Science and Engineering Vol. 7, e10 (2019)

Acknowledgement:

The project has been supported by Ministry of Research, Innovation and Digitalization, program ELI-RO (Romania)