@article{10902/2185,
year = {2011},
month = {8},
url = {http://hdl.handle.net/10902/2185},
abstract = {Using data corresponding to 6.0  fb-1 of pp̅ collisions at √s=1.96  TeV collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon in the central region with 10 GeV or more of transverse energy tt̅ γ. The events are selected by looking for a lepton (ℓ or μ), a photon (γ), significant transverse momentum imbalance (E̸T), large total transverse energy, and three or more jets, with at least one identified as containing a b quark (b). Using an event selection optimized for the tt̅ γ candidate sample, we also measure the cross section of tt̅ (σtt̅ ). We measure the tt̅ γ cross section (σtt̅ γ) to be 0.18±0.08  pb, and the ratio of σtt̅ γ to σtt̅ to be 0.024±0.009. We observe a probability of 0.0015 (3.0 standard deviations) of the background (non-tt̅ γ events alone producing 30 events or more.},
organization = {We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. Uli Baur, Frank Petriello, Alexander Belyaev, Edward Boos, Lev Dudko, Tim Stelzer, and Steve Mrenna were extraordinarily helpful with the SM predictions. This work was supported by the U. S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A. P. Sloan Foundation; the Bundesministerium für Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, UK; the Institut National de Physique Nucleaire et Physique des Particules/CNRS; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; the Academy of Finland; and the Australian Research Council (ARC).},
publisher = {American Physical Society},
publisher = {Physical Review D - Particles, Fields, Gravitation and Cosmology, 2011, 84(3), 031104(R)},
title = {Evidence for tt̅ γ production and measurement of σtt̅ γ/σtt̅},
author = {Aaltonen, Timo Antero and Álvarez González, Bárbara and Casal Laraña, Bruno and Cuevas Maestro, Francisco Javier and Gómez Gramuglio, Gervasio and Palencia Cortezón, José Enrique and Rodrigo Anoro, Teresa and Ruiz Jimeno, Alberto and Scodellaro, Luca and Vila Álvarez, Iván  and Vilar Cortabitarte, Rocío and Vizán García, Jesús Manuel},
}