Studies of nonlinear QED in collisions of 46.6 GeV electrons with intense laser pulses

Journal Article · Mon Nov 01 00:00:00 EST 1999 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.60.092004· OSTI ID:692535

Bamber, C; Boege, S J; Koffas, T; Kotseroglou, T; Melissinos, A C; Meyerhofer, D D; Reis, D A; Ragg, W ^[1]; Bula, C; McDonald, K T; Prebys, E J ^[2]; Burke, D L; Field, R C; Horton-Smith, G; Spencer, J E; Walz, D ^[3]; Berridge, S C; Bugg, W M; Shmakov, K; Weidemann, A W ^[4]

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1. Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)
2. Joseph Henry Laboratories, Princeton University, Princeton, New Jersey 08544 (United States)
3. Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
4. Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States)

We report on measurements of quantum electrodynamic processes in an intense electromagnetic wave, where nonlinear effects (both multiphoton and vacuum polarization) are prominent. Nonlinear Compton scattering and electron-positron pair production have been observed in collisions of 46.6 GeV and 49.1 GeV electrons of the Final Focus Test Beam at SLAC with terawatt pulses of 1053 nm and 527 nm wavelengths from a Nd:glass laser. Peak laser intensities of {approx}0.5{times}10{sup 18}&hthinsp;W/cm{sup 2} have been achieved, corresponding to a value of {approx}0.4 for the parameter {eta}=eE{sub rms}/m{omega}{sub 0}c and to a value of {approx}0.25 for the parameter {Upsilon}{sub e}=E{sub rms}{sup {star}}/E{sub crit}=eE{sub rms}{sup {star}}{h_bar}/m{sup 2}c{sup 3}, where E{sub rms}{sup {star}} is the rms electric field strength of the laser in the electron rest frame. We present data on the scattered electron spectra arising from nonlinear Compton scattering with up to four photons absorbed from the field. A convolved spectrum of the forward high energy photons is also given. The observed positron production rate depends on the fifth power of the laser intensity, as expected for a process where five photons are absorbed from the field. The positrons are interpreted as arising from the collision of a high-energy Compton scattered photon with the laser beam. The results are found to be in agreement with theoretical predictions. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 692535
• Journal Information: Physical Review, D, Vol. 60, Issue 9; Other Information: PBD: Nov 1999
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ELECTRON SPECTRA
QUANTUM ELECTRODYNAMICS
COMPTON EFFECT
PHOTON-ELECTRON INTERACTIONS
POSITRONS
PAIR PRODUCTION