Positron Production in Multiphoton Light-by-Light Scattering
- SLAC
We present the results of an experimental study on e{sup +}e{sup -} pair production during the collision of a low emittance 46.6 GeV electron beam with terawatt laser pulses from a Nd:glass laser at 527 nm wavelength and with linear polarization. The experiment was conducted at the Final Focus Test Beam facility in the Stanford Linear Accelerator Center. Results with a 49.1 GeV electron beam are also included. A signal of 106 {+-} 14 positrons for the 46.6 GeV electron beam case and of 22 {+-} 10 positrons for the 49.1 GcV case above background, has been detected. We interpret the positrons as the products of a two-step process during which laser photons are backscattered to high energy gamma photons that absorb in their turn several laser photons in order to produce a e{sup +}e{sup -} pair. The data compare well with the existing theoretical models. This is the first observation in the laboratory of inelastic Light-by-Light scattering with only real photons. Alternatively, the data are interpreted as a manifestation of the spontaneous breakdown of the vacuum under the influence of an intense external alternating electric field.
- Research Organization:
- Stanford Linear Accelerator Center, Menlo Park, CA (US)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 813362
- Report Number(s):
- SLAC-R-626
- Country of Publication:
- United States
- Language:
- English
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Positron production in multiphoton light-by-light scattering
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