Positron Production in Multiphoton Light-by-Light Scattering [Thesis]

Technical Report · Mon Jun 01 04:00:00 EDT 1998

DOI:https://doi.org/10.2172/1454240· OSTI ID:1454240

Koffas, Thomas ^[1]

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1. Stanford Univ., CA (United States); Univ. of Rochester, NY (United States)

We present the results of an experimental study on e⁺e^- 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 GeV case above background, has been detected. We interpret the positrons as the products of a two-step process during which Iaser photons are backscattered to high energy gamma photons that absorb in their turn several laser photons in order to produce a e⁺e^- pair. The data compare well with the existing theoretical models. This is the first observation in the laboratory of inelastic Iight-by-Iight 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: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1454240
• Report Number(s): SLAC-R--626
• Country of Publication: United States
• Language: English

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