Search for top-quark production via flavor-changing neutral currents in W+1 jet events at CDF

• Published in: Physical review letters Vol. 102; no. 15; p. 151801
• Main Authors: Alvarez González, B, Antos, J, Aurisano, A, Barbaro-Galtieri, A, Bhatti, A, Bizjak, I, Blumenfeld, B, Boudreau, J, Burkett, K, Busetto, G, Buzatu, A, Canepa, A, Carls, B, Carlsmith, D, Carron, S, Cavaliere, V, Chang, S H, Chiarelli, G, Chou, J P, Chwalek, T, Convery, M E, Crescioli, F, Cully, J C, Deninno, M, di Giovanni, G P, Dube, S, Elagin, A, Errede, D, Fedorko, W T, Feild, R G, Flanagan, G, Forrest, R, Frank, M J, Gallinaro, M, Gibson, K, Giurgiu, G, Gold, M, Gomez, G, Gorelov, I, Grundler, U, Guimaraes da Costa, J, Hahn, K, Han, J Y, Heck, M, Hsu, S-C, Hussein, M, Jeon, E J, Karchin, P E, Kim, H W, Kim, M J, Klimenko, S, Kruse, M, Krutelyov, V, Kuhr, T, Lecompte, T, Loginov, A, Luci, C, Lungu, G, Marino, C P, McNulty, R, Merkel, P, Miller, R, Morello, M J, Muller, Th, Nachtman, J, Norniella, O, Oakes, L, Orava, R, Paramonov, A A, Pauletta, G, Pianori, E, Pounder, N, Pueschel, E, Richter, S, Sartori, L, Schmidt, E E, Schmidt, M A, Schmidt, M P, Scodellaro, L, Sedov, A, Sfyrla, A, Slaunwhite, J, Soha, A, Squillacioti, P, Stelzer-Chilton, O, Thomson, E, Tipton, P, Ttito-Guzmán, P, Tkaczyk, S, Tourneur, S, Ukegawa, F, Vataga, E, Velev, G, Warburton, A, Williams, H H, Wolfe, C, Yamaoka, J, Yoshida, T, Zanello, L, Zhang, X
• Format: Journal Article
• Language: English
• Published: United States 17.04.2009
• ISSN: 0031-9007
• DOI: 10.1103/PhysRevLett.102.151801

We report on a search for the non-standard-model process u(c) + g --> t using pp[over ] collision data collected by the Collider Detector at Fermilab II detector corresponding to 2.2 fb;{-1}. The candidate events are classified as signal-like or backgroundlike by an artificial neural network. The observed discriminant distribution yields no evidence for flavor-changing neutral current top-quark production, resulting in an upper limit on the production cross section sigma(u(c) + g --> t) < 1.8 pb at the 95% C.L. Using theoretical predictions we convert the cross section limit to upper limits on flavor-changing neutral current branching ratios: B(t --> u + g) < 3.9 x 10;{-4} and B(t --> c + g) < 5.7 x 10;{-3}.