Publications by authors named "Girolamo A"

A search for singly produced vector-like quarks, where can be either a quark with charge [Formula: see text] or a quark with charge [Formula: see text], is performed in proton-proton collisions recorded with the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 20.3 fb[Formula: see text] and was produced with a centre-of-mass energy of [Formula: see text] TeV.

View Article and Find Full Text PDF

This paper presents measurements of distributions of charged particles which are produced in proton-proton collisions at a centre-of-mass energy of [Formula: see text] and recorded by the ATLAS detector at the LHC. A special dataset recorded in 2012 with a small number of interactions per beam crossing (below 0.004) and corresponding to an integrated luminosity of 160 [Formula: see text] was used.

View Article and Find Full Text PDF
Article Synopsis
  • - The study focuses on measuring event-shape observables using charged particles from inclusive boson events, specifically through electron and muon decay modes, analyzing data from the ATLAS detector at the LHC.
  • - Measurements involve various distributions (like multiplicity and transverse thrust) of charged particles, excluding the decay lepton pair, and are particularly sensitive to the underlying event properties at low transverse momentum of the boson.
  • - Comparison of these observables with predictions from Monte Carlo generators (Pythia 8, Sherpa, and Herwig 7) shows that the models generally perform better at high boson transverse momenta than at low momenta, especially for observables less influenced by particle multiplicity.
View Article and Find Full Text PDF

The number of charged particles inside jets is a widely used discriminant for identifying the quark or gluon nature of the initiating parton and is sensitive to both the perturbative and non-perturbative components of fragmentation. This paper presents a measurement of the average number of charged particles with [Formula: see text] [Formula: see text] inside high-momentum jets in dijet events using 20.3 fb[Formula: see text] of data recorded with the ATLAS detector in collisions at [Formula: see text] [Formula: see text] collisions at the LHC.

View Article and Find Full Text PDF

This paper presents a new method of reconstructing the individual charged and neutral hadrons in tau decays with the ATLAS detector. The reconstructed hadrons are used to classify the decay mode and to calculate the visible four-momentum of reconstructed tau candidates, significantly improving the resolution with respect to the calibration in the existing tau reconstruction. The performance of the reconstruction algorithm is optimised and evaluated using simulation and validated using samples of [Formula: see text] and [Formula: see text]+jets events selected from proton-proton collisions at a centre-of-mass energy [Formula: see text], corresponding to an integrated luminosity of 5 [Formula: see text].

View Article and Find Full Text PDF

This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at [Formula: see text] TeV in 2015. Using a large sample of [Formula: see text] and [Formula: see text] decays from 3.2 fb[Formula: see text] of collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations.

View Article and Find Full Text PDF

Distributions of transverse momentum [Formula: see text] and the related angular variable [Formula: see text] of Drell–Yan lepton pairs are measured in 20.3 fb[Formula: see text] of proton–proton collisions at [Formula: see text] TeV with the ATLAS detector at the LHC. Measurements in electron-pair and muon-pair final states are corrected for detector effects and combined.

View Article and Find Full Text PDF

The production rates of prompt and non-prompt [Formula: see text] and [Formula: see text] mesons in their dimuon decay modes are measured using 2.1 and 11.4 fb[Formula: see text] of data collected with the ATLAS experiment at the Large Hadron Collider, in proton-proton collisions at [Formula: see text] and 8 respectively.

View Article and Find Full Text PDF

A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ( or [Formula: see text]) with the same electric charge or at least three isolated leptons. The search also utilises -tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton-proton collisions at [Formula: see text] TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.

View Article and Find Full Text PDF
Article Synopsis
  • * Key variables used for differentiation include jet mass, jet charge, and a \(\tau\)-tagging discriminant, leading to the development of a likelihood tagger for better identification.
  • * Although direct measurement of tagging efficiencies is not possible due to a lack of pure samples, the tagger's modeling with a sample enriched in \(W/Z\) events indicates strong predictive performance for future data processing.
View Article and Find Full Text PDF

This article presents the sensitivity of the ATLAS experiment to the lepton-flavour-violating decays of [Formula: see text]. A method utilising the production of [Formula: see text] leptons via [Formula: see text] decays is used. This method is applied to the sample of 20.

View Article and Find Full Text PDF

Results of a search for new phenomena in events with at least three photons are reported. Data from proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb[Formula: see text], were collected with the ATLAS detector at the LHC.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates how the number of charged particles produced in proton-lead collisions changes depending on how central the collision is, using data collected by the ATLAS detector at the Large Hadron Collider.
  • It focuses on measuring the mean charged-particle multiplicity across various pseudorapidity values and finds that the particle distribution demonstrates significant variation based on collision centrality, becoming more asymmetric as collisions become more central.
  • Three models are used to estimate the number of nucleons involved in the collision, revealing differing outcomes for charged-particle multiplicities, which emphasizes the need to consider color fluctuations in these interactions for more accurate modeling.
View Article and Find Full Text PDF

The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton-proton collision data with a centre-of-mass energy of [Formula: see text] TeV corresponding to an integrated luminosity of [Formula: see text][Formula: see text]. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti-[Formula: see text] algorithm with distance parameters [Formula: see text] or [Formula: see text], and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations.

View Article and Find Full Text PDF

This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 [Formula: see text] of collisions at a centre-of-mass energy of [Formula: see text] TeV, although in some case an additional [Formula: see text] of collision data at [Formula: see text] TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space.

View Article and Find Full Text PDF

Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as -hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.

View Article and Find Full Text PDF

Studies of the spin, parity and tensor couplings of the Higgs boson in the [Formula: see text], [Formula: see text] and [Formula: see text] decay processes at the LHC are presented. The investigations are based on [Formula: see text] of collision data collected by the ATLAS experiment at [Formula: see text] TeV and [Formula: see text] TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers [Formula: see text], 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.

View Article and Find Full Text PDF

The paper presents studies of Bose-Einstein Correlations (BEC) for pairs of like-sign charged particles measured in the kinematic range [Formula: see text] 100 MeV and [Formula: see text] 2.5 in proton collisions at centre-of-mass energies of 0.9 and 7 TeV with the ATLAS detector at the CERN Large Hadron Collider.

View Article and Find Full Text PDF

Results of a search for new phenomena in events with large missing transverse momentum and a Higgs boson decaying to two photons are reported. Data from proton-proton collisions at a center-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb^{-1} have been collected with the ATLAS detector at the LHC.

View Article and Find Full Text PDF

A search for Higgs boson pair production [Formula: see text] is performed with 19.5 fb[Formula: see text] of proton-proton collision data at [Formula: see text] TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum [Formula: see text] system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated -tagged track-jets.

View Article and Find Full Text PDF

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3  fb^{-1} of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of sqrt[s]=8  TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H→γγ and H→ZZ^{*}→4ℓ event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions.

View Article and Find Full Text PDF

The effect of nixtamalization on the content of fumonisins (FBs), hydrolysed (HFBs) and partially hydrolysed (PHFBs) fumonisins in maize was investigated at laboratory-scale. Maize naturally contaminated with FBs and PHFBs was cooked with lime. Starting raw maize, steeping and washing waters and final masa fractions were analysed for toxin content.

View Article and Find Full Text PDF

A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at [Formula: see text] TeV from collisions corresponding to an integrated luminosity of 20.3 fb[Formula: see text]are examined.

View Article and Find Full Text PDF

A search for the Standard Model Higgs boson produced in association with a top-quark pair, [Formula: see text], is presented. The analysis uses 20.3 fb of collision data at [Formula: see text], collected with the ATLAS detector at the Large Hadron Collider during 2012.

View Article and Find Full Text PDF

The aim of this work is to evaluate the in vitro microbicidal activity of vaginal suppositories (VS) containing tea tree oil (TTO-VS) towards Candida spp. and vaginal probiotics. A total of 20 Candida spp.

View Article and Find Full Text PDF