Positron production in multiphoton light-by-light scattering

Journal Article · Sat Feb 01 04:00:00 EST 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.52962· OSTI ID:664555

A signal of 106{plus_minus}14 positrons above background has been observed in collisions of a low-emittance 46.6-GeV electron beam with terawatt pulses from a Nd:glass laser at 527 nm wavelength in an experiment at the Final Focus Test Beam at SLAC. Peak laser intensities of {approximately}1.3{times}10{sup 18}W/cm{sup 2} have been achieved corresponding to a value of 0.3 for the parameter {Upsilon}=scr(E){sup {asterisk}}/scr(E){sub crit} where scr( E){sup {asterisk}}=2{gamma}scr(E){sub lab} is the electric field strength of the laser transformed to the rest frame of the electron beam and scr(E){sub crit}=m{sup 2}c{sup 3}/e{h_bar}=1.3{times}10{sup 16}V/cm is the QED critical field strength. The positrons are interpreted as arising from a two-step process in which laser photons are backscattered to GeV energies by the electron beam followed by a collision between the high-energy photon and several laser photons to produce an electron-positron pair. These results are the first laboratory evidence for a light-by-light scattering process involving only real photons. {copyright} {ital 1997 American Institute of Physics.}

• Research Organization: Princeton University
• DOE Contract Number: FG02-91ER40671; FG02-91ER40685; FG02-91ER40627
• OSTI ID: 664555
• Report Number(s): CONF-960836--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 396; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CROSS SECTIONS
GEV RANGE 10-100
LASER RADIATION
PARTICLE PRODUCTION
PHOTON-ELECTRON INTERACTIONS
PHOTON-PHOTON INTERACTIONS
POSITRONS
VISIBLE SPECTRA