1533 documents found, page 1 of 154
Porque fazemos ciência?
Castro, Nuno Filipe[Excerto] Ao longo das últimas décadas tem havido um consenso bastante alargado sobre a importância da ciência enquanto ferramenta de desenvolvimento humano e social. Este consenso tem vindo, em geral, a ser partilhado pela classe política portuguesa, ainda que nem sempre traduzido na devida proporção em recursos alocados ao sistema nacional de ciência, tecnologia e inovação (e.g. O Futuro da Ciência e da Unive...
Observation of VVZ production at √s=13 TeV with the ATLAS detector
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA search for the production of three massive vector bosons, \( V V Z (V = W, Z) \), in proton–proton collisions at \( \sqrt{s} = 13 \) TeV is performed using data with an integrated luminosity of 140 fb\(^{-1}\) recorded by the ATLAS detector at the Large Hadron Collider. Events produced in the leptonic final states \( W W Z \rightarrow \ell \nu \ell \nu \ell \ell \) (\( \ell = e, \mu \)), \( W Z Z \rightarrow ...
Configuration, Performance, and Commissioning of the ATLAS b-jet Triggers for t...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationIn 2022 and 2023, the Large Hadron Collider produced approximately two billion hadronic interactions each second from bunches of protons that collide at a rate of 40 MHz. The ATLAS trigger system is used to reduce this rate to a few kHz for recording. Selections based on hadronic jets, their energy, and event topology reduce the rate to \( \mathcal{O}(10) \) kHz while maintaining high efficiencies for important...
Test of lepton flavour universality in W-boson decays into electrons and τ-lept...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA measurement of the ratio of the branching fractions, \( R_{\tau /e} = B(W \rightarrow \tau \nu) / B(W \rightarrow e \nu) \), is performed using a sample of W bosons originating from top-quark decays to final states containing \(\tau\)-leptons or electrons. This measurement uses pp collisions at \( \sqrt{s} = 13 \) TeV, collected by the ATLAS experiment at the Large Hadron Collider during Run 2, corresponding ...
A continuous calibration of the ATLAS flavour-tagging classifiers via optimal t...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA calibration of the ATLAS flavour-tagging algorithms using a new calibration procedure based on optimal transportation maps is presented. Simultaneous, continuous corrections to the b-jet, c-jet, and light-flavour jet classification probabilities from jet-tagging algorithms in simulation are derived for b-jets using \( t\overline{t} \rightarrow e\mu\nu\nu bb \) data. After application of the derived calibratio...
A search for dark matter produced in association with a dark Higgs boson decayi...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA search is performed for dark matter particles produced in association with a resonant pair of Higgs bosons using \( 140 \, \text{fb}^{-1} \) of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. This signature is expected in some extensions of the Standard Model predicting the production of dark matter particles, and is interpreted in ter...
The performance of missing transverse momentum reconstruction and its significa...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationThis paper presents the reconstruction of missing transverse momentum (\( p_{\text{miss}} \ T \)) in proton–proton collisions, at a center-of-mass energy of 13 TeV. This is a challenging task involving many detector inputs, combining fully calibrated electrons, muons, photons, hadronically decaying \(\tau\)-leptons, hadronic jets, and soft activity from remaining tracks. Possible double counting of momentum is ...
Search for Dark Matter Produced in Association with a Dark Higgs Boson in the b...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA search is performed for dark matter particles produced in association with a resonantly produced pair of \( b \)-quarks with \( 30 < m_{b\bar{b}} < 150 \) GeV using 140 fb\(^{-1}\) of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. This signature is expected in extensions of the standard model predicting the production of dark matter particles, in parti...
Search for cascade decays of charged sleptons and sneutrinos in final states wi...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationA search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with \( 140 \, \text{fb}^{-1} \) of proton-proton (pp) collisions at a center-of-mass energy of \( \sqrt{s} = 13 \, \text{TeV} \) recorded by the ATLAS detector at the Large Hadron Collider. This pap...
Differential cross-section measurements of D± and Ds± meson production in proto...
Castro, Nuno Filipe; Onofre, A.; ATLAS CollaborationThe production of \( D^\pm \) and \( D^\pm_s \) charmed mesons is measured using the \( D^\pm / D^\pm_s \rightarrow \phi(\mu\mu) \pi^\pm \) decay channel with 137 fb\(^{-1}\) of \( \sqrt{s} = 13 \) TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider during the years 2016--2018. The charmed mesons are reconstructed in the range of transverse momentum \( 12 < p_T < 100 ...