Percorrer por autor "ATLAS collaboration (2842 authors)"
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- Measurements of top-quark pair differential cross-sections in the lepton+jets channel in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detectorPublication . ATLAS collaboration (2842 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutMeasurements of differential cross-sections of top-quark pair production in fiducial phase-spaces are presented as a function of top-quark and $ t\overline{t} $ system kinematic observables in proton-proton collisions at a centre-of-mass energy of $ \sqrt{s}=13 $ TeV. The data set corresponds to an integrated luminosity of 3.2 fb$^{−1}$, recorded in 2015 with the ATLAS detector at the CERN Large Hadron Collider. Events with exactly one electron or muon and at least two jets in the final state are used for the measurement. Two separate selections are applied that each focus on different top-quark momentum regions, referred to as resolved and boosted topologies of the $ t\overline{t} $ final state. The measured spectra are corrected for detector effects and are compared to several Monte Carlo simulations by means of calculated χ$^{2}$ and p-values.
- Search for new phenomena in events containing a same-flavour opposite-sign dilepton pair, jets, and large missing transverse momentum in $\sqrt{s}=$ 13 $pp$ collisions with the ATLAS detectorPublication . ATLAS collaboration (2842 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutTwo searches for new phenomena in final states containing a same-flavour opposite-sign lepton (electron or muon) pair, jets, and large missing transverse momentum are presented. These searches make use of proton–proton collision data, collected during 2015 and 2016 at a centre-of-mass energy $\sqrt{s}=13$ $\text {TeV}$ by the ATLAS detector at the large hadron collider, which correspond to an integrated luminosity of $14.7~\mathrm {fb}^{-1}$ . Both searches target the pair production of supersymmetric particles, squarks or gluinos, which decay to final states containing a same-flavour opposite-sign lepton pair via one of two mechanisms: a leptonically decaying Z boson in the final state, leading to a peak in the dilepton invariant-mass distribution around the Z boson mass, and decays of neutralinos (e.g. $\tilde{\chi }_2^0 \rightarrow \ell ^+\ell ^- \tilde{\chi }_1^0$ ), yielding a kinematic endpoint in the dilepton invariant-mass spectrum. The data are found to be consistent with the Standard Model expectation. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as 1.70 $\text {TeV}$ (980 $\text {GeV}$ ).
- Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detectorPublication . ATLAS collaboration (2842 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Onofre, António; Palma, Alberto; Pedro, Rute; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutStudies of the spin, parity and tensor couplings of the Higgs boson in the $H \rightarrow ZZ^{*} \rightarrow 4 \ell $ , $H \rightarrow WW^{*} \rightarrow e \nu \mu \nu $ and $H \rightarrow \gamma \gamma $ decay processes at the LHC are presented. The investigations are based on $25\,\mathrm{fb}^{-1}$ of pp collision data collected by the ATLAS experiment at $\sqrt{s}=7$ TeV and $\sqrt{s}=8$ TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers $J^{P}=0^{+}$ , is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at more than 99.9 % confidence level. Using the $H \rightarrow ZZ^{*} \rightarrow 4 \ell $ and $H \rightarrow WW^{*} \rightarrow e \nu \mu \nu $ decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. The observed distributions of variables sensitive to the non-SM tensor couplings are compatible with the SM predictions and constraints on the non-SM couplings are derived.