Photoproduction of J/psi and high mass e+e- in ultra-peripheral Au + Au collisions at root s(NN) = GeV
We present the first measurement of photoproduction of J/{Psi} and of two-photon production of high-mass e{sup +}e{sup -} pairs in electromagnetic (or ultra-peripheral) nucleus-nucleus interactions, using Au + Au data at {radical}s{sub NN}. The events are tagged with forward neutrons emitted following Coulomb excitation of one or both Au* nuclei. The event sample consists of 28 events with me{sup +}e{sup -} > 2 GeV/c{sup 2} with zero like-sign background. The measured cross sections at midrapidity of d{sigma}/dy (J/{Psi} + Xn, y = 0) = 76 {+-} 33(stat) {+-} 11(syst) {mu}b and d{sup 2}{sigma}/dm dy (e{sup +}e{sup -} + Xn, y = 0) = 86 {+-} 23(stat) {+-} 16(syst) {mu}b/(GeV/c{sup 2}) for me{sup +}e{sup -} {element_of} [2.0,2.8] GeV/c{sup 2} have been compared and found to be consistent with models for photoproduction of J/{Psi} and QED based calculations of two-photon production of e{sup +}e{sup -} pairs.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center
- Sponsoring Organization:
- RIKEN
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1040213
- Report Number(s):
- BNL-90626-2009-JA; PYLBAJ; R&D Project: PO-3; TRN: US1202353
- Journal Information:
- Physics Letters, (Section) B, Vol. 679, Issue 4; ISSN 0370-2693
- Country of Publication:
- United States
- Language:
- English
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