Engineering topics
Adamczyk, L.
Publications and source records attributed to Adamczyk, L..
Measurement of the charge asymmetry in highly boosted top-quark pair production in s = 8 TeV pp collision data collected by the ATLAS experiment
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Measurement of the dependence of transverse energy production at large pseudorapidity on the hard-scattering kinematics of proton–proton collisions at s = 2.76 TeV with ATLAS
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Evidence for single top-quark production in the s-channel in proton–proton collisions at s = 8 TeV with the ATLAS detector using the Matrix Element Method
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A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W' → WZ for bosons in the transverse momentum range 200 GeV < p T < 400 GeV in s= 8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of ϵ Z = 90 , 50, and 10 % , one can achieve W + -boson tagging rejection factors (1 / ϵ W+ ) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high p T , hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a tt¯ -enriched sample of events in 20.3 fb - 1 of data at √s= 8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.
Observation of Long-Range Elliptic Azimuthal Anisotropies in s = 13 and 2.76 TeV p p Collisions with the ATLAS Detector
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Probing lepton flavour violation via neutrinoless tau - greater than 3 mu decays with the ATLAS detector
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Search for dark matter produced in association with a Higgs boson decaying to two bottom quarks in pp collisions at root s=8 TeV with the ATLAS detector
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Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton-lead collisions at root s(NN)=5.02 TeV with the ATLAS detector
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Search for anomalous couplings in the W tb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector
The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb -1 of proton-proton collision data at √s=7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured to be 0.37 ± 0.07 (stat.⊕syst.). The phase δ - between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be -0.014π ± 0.036π (stat.⊕syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g R and V L , yielding Re[g R /V L ] ϵ [-0.36, 0.10] and Im[g R /V L ] ϵ [-0.17, 0.23] with a correlation of 0.11. We find the results are in good agreement with the predictions of the Standard Model.
Combination of searches for WW, WZ, and ZZ resonances in pp collisions at s = 8 TeV with the ATLAS detector
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Measurement of the Transverse Single-Spin Asymmetry in p ↑ + p → W ± / Z 0 at RHIC
In this paper, we present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at $\sqrt{s}$ = 500 GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse-momentum-dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. In conclusion, these data provide the first experimental investigation of the nonuniversality of the Sivers function, fundamental to our understanding of QCD.
Search for new phenomena in events with at least three photons collected in pp collisions at √s = 8 TeV with the ATLAS detector
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 -1 , were collected with the ATLAS detector at the LHC. The observed data are well described by the Standard Model. Limits at the 95 % confidence level on new phenomena are presented based on the rate of events in an inclusive signal region and a restricted signal region targeting the rare decay Z→3γ, as well as di-photon and tri-photon resonance searches. For a Standard Model Higgs boson decaying to four photons via a pair of intermediate pseudoscalar particles (a), limits are found to be σ× BR (h→aa)× BR (a→γγ) 2 <10 -3 σSM for 10 GeV a < 62 GeV. Finally, limits are also presented for Higgs boson-like scalars (H) for m H > 125 GeV, and for a Z' decaying to three photons via Z'→a+γ→3γ. Additionally, the observed limit on the branching ratio of the Z boson decay to three photons is found to be BR(Z→3γ)<2.2×10 -6 , a result five times stronger than the previous result from LEP.
Centrality, rapidity, and transverse momentum dependence of isolated prompt photon production in lead-lead collisions at root S-NN=2.76 TeV measured with the ATLAS detector
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Search for magnetic monopoles and stable particles with high electric charges in 8 TeV p p collisions with the ATLAS detector
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Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC
In this paper, we present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au + Au collisions for energies ranging from √sNN = 7.7 to 200 GeV. The third harmonic v$2\atop{3}${ 2 } = , where Φ1 - Φ2 is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη = η1-η2 . Nonzero v$2\atop{3}${ 2 } is directly related to the previously observed large- Δη narrow- ΔΦ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, v$2\atop{3}${ 2 } persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, v$2\atop{3}${ 2 } is consistent with zero. Finally, when scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, v$2\atop{3}${ 2 } for central collisions shows a minimum near √sNN = 20 GeV .
Search for charged Higgs bosons in the H ± → tb decay channel in pp collisions at s = 8 $$ \sqrt{s}=8 $$ TeV using the ATLAS detector
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Erratum to: Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector
This is an erratum to Eur. Phys. J.C. (2015) 75: 476. Unfortunately in the HTML of the article the authors, M. Ishino, T. Kunigo, T. Sumida and T. Tashiro, are assigned to the wrong affiliation. In the PDF of the article the assignment to the affiliation is correct.