Observation of two-source interference in the photoproduction reaction AuAu --> AuAurho0

• Published in: Physical review letters 2009-03, Vol.102 (11), p.112301-112301
• Main Authors: Abelev, B I, Aggarwal, M M, Ahammed, Z, Anderson, B D, Arkhipkin, D, Averichev, G S, Bai, Y, Balewski, J, Barannikova, O, Barnby, L S, Baudot, J, Baumgart, S, Beavis, D R, Bellwied, R, Benedosso, F, Betancourt, M J, Betts, R R, Bhardwaj, S, Bhasin, A, Bhati, A K, Bichsel, H, Bielcik, J, Bielcikova, J, Biritz, B, Bland, L C, Bombara, M, Bonner, B E, Botje, M, Bouchet, J, Braidot, E, Brandin, A V, Bruna, E, Bueltmann, S, Burton, T P, Bystersky, M, Cai, X Z, Caines, H, Calderón de la Barca Sánchez, M, Callner, J, Catu, O, Cebra, D, Cendejas, R, Cervantes, M C, Chajecki, Z, Chaloupka, P, Chattopadhyay, S, Chen, H F, Chen, J H, Chen, J Y, Cheng, J, Cherney, M, Chikanian, A, Choi, K E, Christie, W, Chung, S U, Clarke, R F, Codrington, M J M, Coffin, J P, Corliss, R, Cormier, T M, Cosentino, M R, Cramer, J G, Crawford, H J, Das, D, Dash, S, Daugherity, M, De Silva, C, Dedovich, T G, Dephillips, M, Derevschikov, A A, Derradi de Souza, R, Didenko, L, Djawotho, P, Dogra, S M, Dong, X, Drachenberg, J L, Draper, J E, Du, F, Dunlop, J C, Dutta Mazumdar, M R, Edwards, W R, Efimov, L G, Elhalhuli, E, Elnimr, M, Emelianov, V, Engelage, J, Eppley, G, Erazmus, B, Estienne, M, Eun, L, Fachini, P, Fatemi, R, Fedorisin, J, Feng, A, Filip, P, Finch, E, Fine, V, Fisyak, Y, Gagliardi, C A, Gaillard, L
• Format: Article
• Language: English
• ISSN: 0031-9007

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 rho{0}. The rho{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 rho{0} production. Since the rho{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.