Published in Physical Review C, Volume 70, Issue 3, September 28, 2004, pages 031902-1-031902-6.
STAR is composed of 63 institutions from 13 countries, with a total of 611 collaborators. A variety of personnel participate in the collaboration, including students, university faculty and staff, national laboratory staff, and engineers.
For more information on the STAR Collaboration, visit https://www.star.bnl.gov
The definitive version is available at https://doi.org/10.1103/PhysRevC.70.031902.
We present data on e+e− pair production accompanied by nuclear breakup in ultraperipheral gold-gold collisions at a center of mass energy of 200GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order diagrams for pair production should be enhanced. We compare the data with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED). The data distributions agree with both calculations, except that the pair transverse momentum spectrum disagrees with the equivalent photon approach. We set limits on higher-order contributions to the cross section.
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NOTE: At the time of publication, the author Thomas Gutierrez was not yet affiliated with Cal Poly.