The cross-section to produce a $W$ boson in association with a top quark is measured differentially with respect to several particle-level final-state observable quantities. The measurements are performed using $36.1$~\mbox{fb$^{-1}$} of $pp$ collision data at $\sqrt{s}=13~\mathrm{TeV}$ collected in 2015 and 2016, by the ATLAS detector at the LHC. Cross-sections are measured in a fiducial phase-space defined by the presence of two charged leptons and exactly one jet identified as containing $B$ hadrons. Measurements are normalised to the fiducial cross-section, causing several of the main uncertainties to cancel. The results are found to be in good agreement with predictions from several Monte Carlo generators.
Proceeding for LHCP2017 conference. Referencing the ATLAS publication note: http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PUBNOTES/ATL-PHYS-PUB-2017-005/
New measurements from ATLAS at the LHC are presented on the total cross section at $\sqrt{s}=8$ TeV from elastic scattering using the ALFA sub-detector and on the inelastic cross section at $\sqrt{s}=13$ TeV using the MBTS sub-detector.
The luminosity determination for the ATLAS detector at the LHC during pp collisions at $\sqrt{s}$ = 8 TeV in 2012 is presented. The evaluation of the luminosity scale is performed using several luminometers, and comparisons between these luminosity detectors are made to assess the accuracy, consistency and long-term stability of the results. A luminosity uncertainty of dL/L = +/- 1.9% is obtained for the 22.7 fb$^{-1}$ of pp collision data delivered to ATLAS at $\sqrt{s}$ = 8 TeV in 2012.
Searches for high-mass resonances decaying to pairs of standard model bosons using ATLAS and CMS detectors are presented. The searches use 15 - 36 $\textrm{fb}^{-1}$ of proton-proton collision data collected at the centre-of-mass energy of 13 TeV at the LHC. Many different final states have been considered and the results are interpreted in a range of theories beyond the standard model of particle physics, most common being heavy vector triplet and warped extra dimensions.
We present a search for new high mass phenomena using the latest data collected by the ATLAS detector at the LHC, corresponding to 36.1 fb$^{-1}$ at $\sqrt{s}$ = 13 TeV. The search is conducted for both resonant and non-resonant new phenomena in dimuon final states. The dimuon invariant mass spectrum is the discriminating variable used in the search. No significant deviations from the Standard Model expectation are observed. Lower limits are set on the signal parameters of interest at 95% credibility level, using a Bayesian interpretation. In particular, a Sequential Standard Model Z' resonanc…
A review of the searches for the SM Higgs boson produced in association with a pair of top quarks, ${t\bar{t}H}$, using up to 13.3 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector at the LHC is presented. Searches in the diphoton, multilepton and $b\bar{b}$ decay channels are summarised. The combination of these searches yields a measured (expected) significance for the observation of the ${t\bar{t}H}$ production process of $2.8 σ$ ($1.8 σ$).
Models with extra gauge symmetry were well motivated extensions of the Standard Model. In this paper, we search for an excess of events in search of a heavy neutral gauge boson Z which is fermiophobic. We are looking at llbb final states where the dilepton channel provides the most stringent constraint on the fermiophobic (FB) model. Since Z is fermiophobic, the production of such particles can occur via vector boson fusion, with subsequent decays into WW or Zh. We observe no significant excess of events over the background-only hypothesis and are able to put the constraint on efficiency times…
Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using 20.3 $fb^{-1}$ of $\sqrt{s}$ = 8 TeV proton-proton collision data
Search for new phenomena with the monojet and missing transverse momentum signature using the ATLAS detector in sqrt(s) = 7 TeV proton-proton collisions
A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb$^{-1}$ of proton--proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at $\sqrt{s}=13$ TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set…
Search for supersymmetry with jets, missing transverse momentum and at least one hadronically decaying tau lepton in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector
Top-quark pairs in association with final state particles are produced in large quantities at the LHC due to the high centre-of-mass energy available in proton-proton collisions. One such topology is that of a prompt photon radiated from the top quark in addition to the final state particles from the top quark decay. Using 36.1 fb$^{-1}$ of data collected at $\sqrt{s}$ = 13 TeV with the ATLAS detector, fiducial cross-section results are shown in the single-lepton and dilepton channels. Object-level and event-level neural networks are used to increase sensitivity.
An overview of the latest results for top pair production in association with a vector gauge boson in the ATLAS detector at LHC is presented. The results involving $Z$ and $W$ bosons are recorded at $\sqrt{13}$ TeV collision energy, while the results involving photons are recorded at $\sqrt{7}$ TeV and $\sqrt{8}$ TeV collision energy.
Measurements of underlying-event properties using neutral and charged particles in pp collisions at 900 GeV and 7 TeV with the ATLAS detector at the LHC
Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton-proton collision data with the ATLAS detector
A search for pair-produced vector-like quarks decaying into a $Z$ boson and a third generation quark using 2015 and 2016 $pp$ collision data at $\sqrt{s}~=~13~$TeV collected by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of $36.1~$fb$^{-1}$, is presented. No significant excess over the Standard Model expectation was found so lower exclusion limits at 95% confidence level were set on the vector-like quark masses at 1030 (1210) GeV for singlet (doublet) $T$ and 1010 (1140) GeV for singlet (doublet) $B$.
This article presents measurements of all three single top-quark production channels. Detailed measurements of $t$-channel single top-quark production using data collected by the ATLAS experiment in proton--proton collisions at a centre-of-mass energy of 8 TeV are shown as well es first results using 13 TeV at the LHC. The associated production of a top quark and a $W$ boson is presented for data collected at 13 TeV, while the first evidence of single top-quark production in the $s$-channel is shown for data collected at 8 TeV.
Search for dark matter candidates and large extra dimensions in events with a photon and missing transverse momentum in pp collision data at sqrt(s) = 7 TeV with the ATLAS detector
Searches for high-mass resonances in the dijet invariant mass spectrum with one or two jets identified as $b$-jets are performed using an integrated luminosity of $3.2$ fb$^{-1}$ of proton--proton collisions with a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the Large Hadron Collider. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% credibility level, excited $b^{*}$ quarks with masses from 1.1 TeV to 2.1 TeV and leptophobic $Z'$ bosons with masses from 1.1 TeV to 1.5 TeV. Contributions of a Gaussian signal shape wit…
ATLAS Sensitivity to Leptoquarks, W_R and Heavy Majorana Neutrinos in Final States with High-pt Dileptons and Jets with Early LHC Data at 14 TeV proton-proton collisions
The production of exclusive $γγ\rightarrow μ^+ μ^-$ events in proton--proton collisions at a centre-of-mass energy of 13 TeV is measured with the ATLAS detector at the LHC, using data corresponding to an integrated luminosity of 3.2 fb$^{-1}$. The measurement is performed for a dimuon invariant mass of 12 GeV $<m_{μ^+μ^-}<$ 70 GeV. The integrated cross-section is determined within a fiducial acceptance region of the ATLAS detector and differential cross-sections are measured as a function of the dimuon invariant mass. The results are compared to theoretical predictions that include corrections…
