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 PDFA search for the exotic meson X(5568) decaying into the B_{s}^{0}π^{±} final state is performed using data corresponding to 9.6 fb^{-1} from pp[over ¯] collisions at sqrt[s]=1960 GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.
View Article and Find Full Text PDFThe CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96 TeV.
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 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 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 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.
View Article and Find Full Text PDFA search for the dimuon decay of the Higgs boson was performed using data corresponding to an integrated luminosity of 36.1 fb^{-1} collected with the ATLAS detector in pp collisions at sqrt[s]=13 TeV at the Large Hadron Collider. No significant excess is observed above the expected background.
View Article and Find Full Text PDFDetailed measurements of -channel single top-quark production are presented. They use 20.2 fb[Formula: see text] of data collected by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of 8 TeV at the LHC.
View Article and Find Full Text PDFEur Phys J C Part Fields
July 2017
The reconstruction of the signal from hadrons and jets emerging from the proton-proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals.
View Article and Find Full Text PDFMeasurements of the electroweak production of a boson in association with two jets at high dijet invariant mass are performed using [Formula: see text] 7 and 8 [Formula: see text] proton-proton collision data produced by the Large Hadron Collider, corresponding respectively to 4.7 and 20.2 fb[Formula: see text] of integrated luminosity collected by the ATLAS detector.
View Article and Find Full Text PDFEur Phys J C Part Fields
July 2017
This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb[Formula: see text] of ATLAS data from 8 TeV proton-proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker.
View Article and Find Full Text PDFEur Phys J C Part Fields
May 2017
This paper presents the method and performance of primary vertex reconstruction in proton-proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of [Formula: see text] TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy.
View Article and Find Full Text PDFDuring 2015 the ATLAS experiment recorded [Formula: see text] of proton-proton collision data at a centre-of-mass energy of [Formula: see text]. The ATLAS trigger system is a crucial component of the experiment, responsible for selecting events of interest at a recording rate of approximately 1 kHz from up to 40 MHz of collisions. This paper presents a short overview of the changes to the trigger and data acquisition systems during the first long shutdown of the LHC and shows the performance of the trigger system and its components based on the 2015 proton-proton collision data.
View Article and Find Full Text PDFResults of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb[Formula: see text] of proton-proton collisions at a centre-of-mass energy of [Formula: see text], is in agreement with the Standard Model expectations, model-independent limits are set on the fiducial cross section for the production of events in this final state.
View Article and Find Full Text PDFEur Phys J C Part Fields
February 2017
Direct searches for lepton flavour violation in decays of the Higgs and bosons with the ATLAS detector at the LHC are presented. The following three decays are considered: [Formula: see text], [Formula: see text], and [Formula: see text]. The searches are based on the data sample of proton-proton collisions collected by the ATLAS detector corresponding to an integrated luminosity of 20.
View Article and Find Full Text PDFTwo 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 [Formula: see text] [Formula: see text] by the ATLAS detector at the large hadron collider, which correspond to an integrated luminosity of [Formula: see text]. 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 boson in the final state, leading to a peak in the dilepton invariant-mass distribution around the boson mass; and decays of neutralinos (e.
View Article and Find Full Text PDFThis article presents measurements of [Formula: see text] differential cross-sections in a fiducial phase-space region, using an integrated luminosity of 3.2 fb[Formula: see text] of proton-proton data at a centre-of-mass energy of [Formula: see text] TeV recorded by the ATLAS experiment at the LHC in 2015. Differential cross-sections are measured as a function of the transverse momentum and absolute rapidity of the top quark, and of the transverse momentum, absolute rapidity and invariant mass of the [Formula: see text] system.
View Article and Find Full Text PDFEur Phys J C Part Fields
March 2017
This paper describes the algorithms for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC). These algorithms were used for all ATLAS results with electrons in the final state that are based on the 2012 collision data produced by the LHC at [Formula: see text] = 8 [Formula: see text]. The efficiency of these algorithms, together with the charge misidentification rate, is measured in data and evaluated in simulated samples using electrons from [Formula: see text], [Formula: see text] and [Formula: see text] decays.
View Article and Find Full Text PDF