| dc.creator | Alconada Verzini, María Josefina | |
| dc.creator | Alonso, Francisco | |
| dc.creator | Anduaga, Xabier Sebastián | |
| dc.creator | Dova, María Teresa | |
| dc.creator | Monticelli, Fernando Gabriel | |
| dc.creator | Wahlberg, Hernán Pablo | |
| dc.creator | The ATLAS Collaboration | |
| dc.date | 2015 | |
| dc.date | 2019-12-04T15:32:32Z | |
| dc.date.accessioned | 2023-07-14T17:32:25Z | |
| dc.date.available | 2023-07-14T17:32:25Z | |
| dc.identifier | http://sedici.unlp.edu.ar/handle/10915/86781 | |
| dc.identifier | issn:1550-7998 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/7427875 | |
| dc.description | A search is performed for top-quark pairs (tt¯) produced together with a photon (γ) with transverse energy greater than 20 GeV using a sample of tt¯ candidate events in final states with jets, missing transverse momentum, and one isolated electron or muon. The data set used corresponds to an integrated luminosity of 4.59 fb<sup>-1</sup> of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. In total, 140 and 222 tt¯γ candidate events are observed in the electron and muon channels, to be compared to the expectation of 79±26 and 120±39 non-tt¯γ background events, respectively. The production of tt¯γ events is observed with a significance of 5.3 standard deviations away from the null hypothesis. The tt¯γ production cross section times the branching ratio (BR) of the single-lepton decay channel is measured in a fiducial kinematic region within the ATLAS acceptance. The measured value is σ<sup>fid</sup><sub>tt¯γ</sub>×BR=63±8(stat)<sup>+17</sup><sub>-13</sub>(syst)±1(lumi) fb per lepton flavor, in good agreement with the leading-order theoretical calculation normalized to the next-to-leading-order theoretical prediction of 48±10 fb. | |
| dc.description | La lista completa de autores que integran el documento puede consultarse en el archivo. | |
| dc.description | Facultad de Ciencias Exactas | |
| dc.description | Instituto de Física La Plata | |
| dc.format | application/pdf | |
| dc.language | en | |
| dc.rights | http://creativecommons.org/licenses/by/3.0/ | |
| dc.rights | Creative Commons Attribution 3.0 Unported (CC BY 3.0) | |
| dc.subject | Ciencias Exactas | |
| dc.subject | Física | |
| dc.subject | proton-proton collisions | |
| dc.subject | ATLAS detector | |
| dc.title | Observation of top-quark pair production in association with a photon and measurement of the tt¯γ production cross section in pp collisions at √s = 7 TeV using the ATLAS detector | |
| dc.type | Articulo | |
| dc.type | Articulo | |
