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- Measurement of the high-mass Drell--Yan differential cross-section in pp collisions at sqrt(s)=7 TeV with the ATLAS detectorPublication . ATLAS collaboration (2916 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Do Valle Wemans, André; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Marques, Carlos; Oliveira, Miguel Alfonso; Onofre, António; Palma, Alberto; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Veloso, Filipe; Wolters, HelmutThis Letter reports a measurement of the high-mass Drell-Yan differential cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. Based on an integrated luminosity of 4.9 fb^-^1, the differential cross-section in the Z/@c^@?->e^+e^- channel is measured with the ATLAS detector as a function of the invariant mass, m_e_e, in the range 11625 GeV and pseudorapidity |@h|<2.5. A comparison is made to various event generators and to the predictions of perturbative QCD calculations at next-to-next-to-leading order.
- Search for microscopic black holes in a like-sign dimuon final state using large track multiplicity with the ATLAS detectorPublication . ATLAS collaboration (2941 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Do Valle Wemans, André; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Marques, Carlos; Oliveira, Miguel Alfonso; Onofre, António; Palma, Alberto; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutA search is presented for microscopic black holes in a like-sign dimuon final state in proton--proton collisions at sqrt(s)= 8 TeV. The data were collected with the ATLAS detector at the Large Hadron Collider in 2012 and correspond to an integrated luminosity of 20.3 fb-1. Using a high track multiplicity requirement, 0.6 +- 0.2 background events from Standard Model processes are predicted and none observed. This result is interpreted in the context of low-scale gravity models and 95% CL lower limits on microscopic black hole masses are set for different model assumptions.
- Search for gluino mediated bottom- and top-squark production in multijet final states in pp collisions at 8 TeVPublication . CMS collaboration (2204 authors); Hollar, Jonathan; Nayak, Aruna; Calpas, Betty; Almeida, Nuno; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Rodrigues Antunes, Joao; Seixas, Joao; Varela, Joao; Vischia, Pietro; Lloret Iglesias, Lara; David Tinoco Mendes, Andre; Musella, Pasquale; Silva, Pedro; Pela, Joao; Leonardo, NunoA search for supersymmetry is presented based on events with large missing transverse energy, no isolated electron or muon, and at least three jets with one or more identified as a bottom-quark jet. A simultaneous examination is performed of the numbers of events in exclusive bins of the scalar sum of jet transverse momentum values, missing transverse energy, and bottom-quark jet multiplicity. The sample, corresponding to an integrated luminosity of 19.4 inverse femtobarns, consists of proton-proton collision data recorded at a center-of-mass energy of 8 TeV with the CMS detector at the LHC in 2012. The observed numbers of events are found to be consistent with the standard model expectation, which is evaluated with control samples in data. The results are interpreted in the context of two simplified supersymmetric scenarios in which gluino pair production is followed by the decay of each gluino to an undetected lightest supersymmetric particle and either a bottom or top quark-antiquark pair, characteristic of gluino mediated bottom- or top-squark production. Using the production cross section calculated to next-to-leading-order plus next-to-leading-logarithm accuracy, and in the limit of a massless lightest supersymmetric particle, we exclude gluinos with masses below 1170 GeV and 1020 GeV for the two scenarios, respectively.