Eur Phys J C Part Fields
January 2019
[This corrects the article DOI: 10.1140/epjc/s10052-017-4819-4.].
View Article and Find Full Text PDFJet substructure observables have significantly extended the search program for physics beyond the standard model at the Large Hadron Collider. The state-of-the-art tools have been motivated by theoretical calculations, but there has never been a direct comparison between data and calculations of jet substructure observables that are accurate beyond leading-logarithm approximation. Such observables are significant not only for probing the collinear regime of QCD that is largely unexplored at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider.
View Article and Find Full Text PDFA direct search for the standard model Higgs boson decaying to a pair of charm quarks is presented. Associated production of the Higgs and Z bosons, in the decay mode ZH→ℓ^{+}ℓ^{-}cc[over ¯] is studied. A data set with an integrated luminosity of 36.
View Article and Find Full Text PDFA search for the narrow structure, X(5568), reported by the D0 Collaboration in the decay sequence X→B_{s}^{0}π^{±}, B_{s}^{0}→J/ψϕ, is presented. The analysis is based on a data sample recorded with the ATLAS detector at the LHC corresponding to 4.9 fb^{-1} of pp collisions at 7 TeV and 19.
View Article and Find Full Text PDFA search for high-mass resonances decaying to τν using proton-proton collisions at sqrt[s]=13 TeV produced by the Large Hadron Collider is presented. Only τ-lepton decays with hadrons in the final state are considered. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.
View Article and Find Full Text PDFThis paper presents a direct measurement of the decay width of the top quark using events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb .
View Article and Find Full Text PDFA search is performed for new phenomena in events having a photon with high transverse momentum and a jet collected in of proton-proton collisions at a centre-of-mass energy of = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The invariant mass distribution of the leading photon and jet is examined to look for the resonant production of new particles or the presence of new high-mass states beyond the Standard Model. No significant deviation from the background-only hypothesis is observed and cross-section limits for generic Gaussian-shaped resonances are extracted.
View Article and Find Full Text PDFA search for neutral heavy resonances is performed in the decay channel using collision data corresponding to an integrated luminosity of , collected at a centre-of-mass energy of 13 by the ATLAS detector at the Large Hadron Collider. No evidence of such heavy resonances is found. In the search for production via the quark-antiquark annihilation or gluon-gluon fusion process, upper limits on as a function of the resonance mass are obtained in the mass range between 200 and up to 5 for various benchmark models: a Higgs-like scalar in different width scenarios, a two-Higgs-doublet model, a heavy vector triplet model, and a warped extra dimensions model.
View Article and Find Full Text PDFA search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton-proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC.
View Article and Find Full Text PDFEur Phys J C Part Fields
February 2018
A measurement of the mass of the boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to of integrated luminosity. The selected data sample consists of candidates in the channel and candidates in the channel. The -boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the boson transverse mass in the electron and muon decay channels, yielding where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty.
View Article and Find Full Text PDFA search for weakly interacting massive dark-matter particles produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and missing transverse momentum are considered. The analysis uses of proton-proton collision data recorded by the ATLAS experiment at TeV in 2015 and 2016.
View Article and Find Full Text PDFThis paper presents a measurement of the polarisation of leptons produced in decays which is performed with a dataset of proton-proton collisions at TeV, corresponding to an integrated luminosity of 20.2 fb recorded with the ATLAS detector at the LHC in 2012. The decays are reconstructed from a hadronically decaying lepton with a single charged particle in the final state, accompanied by a lepton that decays leptonically.
View Article and Find Full Text PDFMeasurements of longitudinal flow correlations are presented for charged particles in the pseudorapidity range using 7 and 470 of Pb+Pb collisions at and 5.02 TeV, respectively, recorded by the ATLAS detector at the LHC. It is found that the correlation between the harmonic flow coefficients measured in two separated intervals does not factorise into the product of single-particle coefficients, and this breaking of factorisation, or flow decorrelation, increases linearly with the separation between the intervals.
View Article and Find Full Text PDFEur Phys J C Part Fields
February 2018
The modification of the production of , , and ( ) in +Pb collisions with respect to their production in collisions has been studied. The +Pb and datasets used in this paper correspond to integrated luminosities of and respectively, collected in 2013 and 2015 by the ATLAS detector at the LHC, both at a centre-of-mass energy per nucleon pair of 5.02 TeV.
View Article and Find Full Text PDFA search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of collisions corresponding to an integrated luminosity of 36.1 fb , recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV.
View Article and Find Full Text PDFThe differential cross-section for the production of a boson in association with a top quark is measured for several particle-level observables. The measurements are performed using of collision data collected with the ATLAS detector at the LHC in 2015 and 2016. Differential cross-sections are measured in a fiducial phase space defined by the presence of two charged leptons and exactly one jet matched to a -hadron, and are normalised with the fiducial cross-section.
View Article and Find Full Text PDFA search for heavy resonances decaying into a pair of bosons leading to and final states, where stands for either an electron or a muon, is presented. The search uses proton-proton collision data at a centre-of-mass energy of 13 corresponding to an integrated luminosity of 36.1 collected with the ATLAS detector during 2015 and 2016 at the Large Hadron Collider.
View Article and Find Full Text PDFThe results of a search for new heavy bosons decaying to an electron or muon and a neutrino using proton-proton collision data at a centre-of-mass energy of TeV are presented. The dataset was collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 36.1 .
View Article and Find Full Text PDFThe inclusive and fiducial production cross-sections are measured in the lepton+jets channel using of proton-proton collision data at a centre-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. Major systematic uncertainties due to the modelling of the jet energy scale and -tagging efficiency are constrained by separating selected events into three disjoint regions. In order to reduce systematic uncertainties in the most important background, the process is modelled using + jets events in a data-driven approach.
View Article and Find Full Text PDFSeveral extensions of the standard model predict associated production of dark-matter particles with a Higgs boson. Such processes are searched for in final states with missing transverse momentum and a Higgs boson decaying to a bb[over ¯] pair with the ATLAS detector using 36.1 fb^{-1} of pp collisions at a center-of-mass energy of 13 TeV at the LHC.
View Article and Find Full Text PDFA search for heavy pseudoscalar (A) and scalar (H) Higgs bosons decaying into a top quark pair (tt[over ¯]) has been performed with 20.3 fb^{-1} of proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a center-of-mass energy sqrt[s]=8 TeV. Interference effects between the signal process and standard model tt[over ¯] production, which are expected to distort the signal shape from a single peak to a peak-dip structure, are taken into account.
View Article and Find Full Text PDFMulti-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in [Formula: see text] collisions at [Formula: see text] = 5.02 and 13 TeV and in [Formula: see text] + Pb collisions at [Formula: see text] = 5.02 TeV, and compared to the results obtained for low-multiplicity [Formula: see text] collisions at [Formula: see text] = 2.
View Article and Find Full Text PDFMeasurements of the production cross section of a [Formula: see text] boson in association with jets in proton-proton collisions at [Formula: see text] TeV are presented, using data corresponding to an integrated luminosity of 3.16 fb[Formula: see text] collected by the ATLAS experiment at the CERN Large Hadron Collider in 2015. Inclusive and differential cross sections are measured for events containing a [Formula: see text] boson decaying to electrons or muons and produced in association with up to seven jets with [Formula: see text] GeV and [Formula: see text].
View Article and Find Full Text PDFEur Phys J C Part Fields
October 2017
With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13 [Formula: see text] for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.
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