Observation of Two-Source Interference in the Photoproduction Reaction AuAu-->AuAu rho
Author(s)Walker, M.; Surrow, Bernd; Sakuma, Tai; Redwine, Robert P.; Milner, Richard G.; Leight, William Axel; Kocoloski, Adam Philip; Jones, Christopher LaDon; Hoffman, A. M.; Corliss, Ross Cameron; Betancourt, Michael Joseph; Balewski, Jan T.; Surrow, Bernd; ... Show more Show less
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In ultraperipheral relativistic heavy-ion collisions, a photon from the electromagnetic field of one nucleus can fluctuate to a quark-antiquark pair and scatter from the other nucleus, emerging as a ρ[superscript 0]. The ρ[superscript 0] production occurs in two well-separated (median impact parameters of 20 and 40 F for the cases considered here) nuclei, so the system forms a two-source interferometer. At low transverse momenta, the two amplitudes interfere destructively, suppressing ρ[superscript 0] production. Since the ρ[superscript 0] decays before the production amplitudes from the two sources can overlap, the two-pion system can only be described with an entangled nonlocal wave function, and is thus an example of the Einstein-Podolsky-Rosen paradox. We observe this suppression in 200 GeV per nucleon-pair gold-gold collisions. The interference is 87%±5%(stat.)±8%(syst.) of the expected level. This translates into a limit on decoherence due to wave function collapse or other factors of 23% at the 90% confidence level.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
Physical Review Letters
American Physical Society
STAR Collaboration et al. “Observation of Two-Source Interference in the Photoproduction Reaction AuAu-->AuAu rho.” Physical Review Letters 102.11 (2009): 112301. © 2009 The American Physical Society.
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