Production of e+e- Pairs Accompanied by Nuclear Dissociation in Ultra-peripheral Heavy Ion Collisions
We present the first data on e{sup +}e{sup -} pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, p{sub T}, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The e{sup +} and e{sup -} p{sub T} spectra are similar, with no evidence for interference effects due to higher-order diagrams.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of High Energy and Nuclear Physics. Division of Nuclear Physics; National Science Foundation (NSF); BMBF Germany, IN2P3 RA RPL EMN France, EPSRC United Kingdom, FAPESP Brazil, Russian Ministry of Science and Technology, Ministry of Education NNSFC China, SFOM Czech Republic, FOM UU Netherlands, DAE DST CSIR India, Swiss National Science Foundation (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 834636
- Report Number(s):
- LBNL-55034; R&D Project: NRNC; TRN: US200433%%258
- Journal Information:
- Physical Review C, Vol. 70; Other Information: Submitted to Physical Review C, Volume 70; Journal Publication Date: 2004; PBD: 7 Apr 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron-positron production in ultra-peripheral heavy-ion collisions with the STAR experiment
Photoproduction of J/psi and of High Mass e+e- in Ultra-Peripheral Au+Au Collisions at s**(1/2) = 200 GeV