Measurement of the Top Quark-Pair Production Cross Section With ATLAS in Pp Collisions at $\sqrt{s}=7$ TeV (open access)

Measurement of the Top Quark-Pair Production Cross Section With ATLAS in Pp Collisions at $\sqrt{s}=7$ TeV

None
Date: June 14, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Measurement of the $\upsilon_{1S}$ Production Cross-Section in $Pp$ Collisions at $\sqrt{s} = 7 TeV in ATLAS (open access)

Measurement of the $\upsilon_{1S}$ Production Cross-Section in $Pp$ Collisions at $\sqrt{s} = 7 TeV in ATLAS

None
Date: June 3, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC (open access)

Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC

None
Date: June 12, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for a Heavy Neutral Particle Decaying Into an Electron and a Muon Using 1 Fb^-1 of ATLAS Data (open access)

Search for a Heavy Neutral Particle Decaying Into an Electron and a Muon Using 1 Fb^-1 of ATLAS Data

None
Date: May 30, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for Contact Interactions in Dimuon Events From $Pp$ Collisions at $\sqrt{s}=7$ TeV With the ATLAS Detector (open access)

Search for Contact Interactions in Dimuon Events From $Pp$ Collisions at $\sqrt{s}=7$ TeV With the ATLAS Detector

None
Date: June 7, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for Diphoton Events with Large Missing Transverse Energy in 7 TeV Proton-Proton Collisions with the ATLAS Detector (open access)

Search for Diphoton Events with Large Missing Transverse Energy in 7 TeV Proton-Proton Collisions with the ATLAS Detector

None
Date: June 11, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for Extra Dimensions Using Diphoton Events in 7 TeV Proton-Proton Collisions with the ATLAS Detector (open access)

Search for Extra Dimensions Using Diphoton Events in 7 TeV Proton-Proton Collisions with the ATLAS Detector

None
Date: May 7, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for Massive Long-lived Highly Ionising Particles with the ATLAS Detector at the LHC (open access)

Search for Massive Long-lived Highly Ionising Particles with the ATLAS Detector at the LHC

None
Date: May 29, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for New Phenomena in ttbar Events with Large Missing Transverse Momentum in Proton-Proton Collisions at sqrt(s)=7$ TeV With the ATLAS Detector (open access)
Search for Pair Production of First Or Second Generation Leptoquarks in Proton-Proton Collisions at sqrt(s)=7 TeV using the ATLAS detector at the LHC (open access)
Search for Strong Gravity Signatures in Same-Sign Dimuon Final States Using the ATLAS Detector at the LHC (open access)

Search for Strong Gravity Signatures in Same-Sign Dimuon Final States Using the ATLAS Detector at the LHC

None
Date: May 20, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Search for Supersymmetry using Final States with One Lepton, Jets, and Missing Transverse Momentum with the ATLAS Detector in $\sqrt{s}=7$ TeV $Pp$ (open access)
Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\sqrt{s} with the ATLAS Detector (open access)

Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\sqrt{s} with the ATLAS Detector

The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.
Date: June 20, 2012
Creator: Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat et al.
Object Type: Article
System: The UNT Digital Library
Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization. (open access)

Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization.

A variety of edge joints utilizing a continuous wave Nd:YAG laser have been produced and examined in a 304-L stainless steel to advance fundamental understanding of the linkage between processing and resultant microstructure in high-rate solidification events. Acquisition of three-dimensional reconstructions via micro-computed tomography combined with traditional metallography has allowed for qualitative and quantitative characterization of weld joints in a material system of wide use and broad applicability. The presence, variability and distribution of porosity, has been examined for average values, spatial distributions and morphology and then related back to fundamental processing parameters such as weld speed, weld power and laser focal length.
Date: May 1, 2012
Creator: Aagesen, Larry K. & Madison, Jonathan D.
Object Type: Report
System: The UNT Digital Library
Combination of CDF and D0 Measurements of the $W$ Boson Helicity in Top Quark Decays (open access)

Combination of CDF and D0 Measurements of the $W$ Boson Helicity in Top Quark Decays

This report talks about Combination of CDF and D0 Measurements of the $W$ Boson Helicity in Top Quark Decays
Date: April 20, 2012
Creator: Aaltonen, T
Object Type: Article
System: The UNT Digital Library
Search for New Heavy Particles Decaying to Z0 Z0 to llll, lljj in p pbar Collisions at Sqrt(s) = 1.96 TeV (open access)

Search for New Heavy Particles Decaying to Z0 Z0 to llll, lljj in p pbar Collisions at Sqrt(s) = 1.96 TeV

We report on a search for anomalous production of Z pairs through a massive resonance decay in data corresponding to 2.5-2.9 fb{sup -1} of integrated luminosity in p{bar p} collisions at {radical}s = 1.96 TeV using the CDF II detector at the Fermilab Tevatron. This analysis, with more data and channels where the Z bosons decay to muons or jets, supersedes the 1.1 fb{sup -1} four-electron channel result previously published by CDF. In order to maintain high efficiency for muons, we use a new forward tracking algorithm and muon identification requirements optimized for these high signal-to-background channels. Predicting the dominant backgrounds in each channel entirely from sideband data samples, we observe four-body invariant mass spectra above 300 GeV/c{sup 2} that are consistent with background. We set limits using the acceptance for a massive graviton resonance that are 7-20 times stronger than the previously published direct limits on resonant ZZ production.
Date: February 1, 2011
Creator: Aaltonen, T.
Object Type: Article
System: The UNT Digital Library
Search for the Higgs boson in the all-hadronic final state using the full CDF data set (open access)

Search for the Higgs boson in the all-hadronic final state using the full CDF data set

None
Date: August 1, 2012
Creator: Aaltonen, T. & Phys., /Helsinki U. /Helsinki Inst. of
Object Type: Article
System: The UNT Digital Library
Limits on Anomalous Trilinear Gauge Couplings in $Z\gamma$ Events from $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV (open access)

Limits on Anomalous Trilinear Gauge Couplings in $Z\gamma$ Events from $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

Using Z{gamma} candidate events collected by the CDF detector at the Tevatron Collider, we search for potential anomalous (non-standard-model) couplings between the Z boson and the photon. At the hard scatter energies typical of the Tevatron, standard model Z{gamma} couplings are too weak to be detected by current experiments; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9 fb{sup -1} in the Z {yields} {nu}{bar {nu}} decay channel and 5.1 fb{sup -1} in the Z {yields} l{sup +}l{sup -} (l = {mu}, e) decay channels. The combination of these measurements provides the most stringent limits to date on Z{gamma} trilinear gauge couplings. Using an energy scale of {Lambda} = 1.5 TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Z{gamma} couplings to be |h{sub 3}{sup {gamma},Z}| < 0.017 and |h{sub 4}{sup {gamma},Z}| < 0.0006. These results are consistent with standard model predictions.
Date: March 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of Event Shapes in Proton-Antiproton Collisions at Center-of-Mass Energy 1.96 TeV (open access)

Measurement of Event Shapes in Proton-Antiproton Collisions at Center-of-Mass Energy 1.96 TeV

A study of event shape observables in proton-antiproton collisions at {radical}s = 1.96 TeV is presented. The data for this analysis were recorded by the CDF II detector at the Tevatron collider. The variables studied are the transverse thrust and thrust minor, both defined in the plane perpendicular to the beam direction. The observables are measured using energies from unclustered calorimeter cells. In addition to studies of the differential distributions, we present the dependence of event shape mean values on the leading jet transverse energy. Data are compared with pythia Tune A and to resummed parton level predictions that were matched to fixed order results at NLO accuracy (NLO+NLL). Predictions from pythia Tune A agree fairly well with the data. However, the underlying event contributes significantly to these observables, making it difficult to make direct comparisons to the NLO+NLL predictions, which do not account for the underlying event. To overcome this difficulty, we introduce a new observable, a weighted difference of the mean values of the thrust and thrust minor, which is less sensitive to the underlying event, allowing for a comparison with NLO+NLL. Both pythia Tune A and the NLO+NLL calculations agree well within the 20% theoretical uncertainty with …
Date: March 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum (open access)

Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum

This letter reports a measurement of the top quark mass, M{sub top}, in data from p{bar p} collisions at {radical}s = 1.96 TeV corresponding to 2.7 fb{sup -1} of integrated luminosity at the Fermilab Tevatron using the CDF II detector. Events with the lepton+jets topology are selected. An unbinned likelihood is constructed based on the dependence of the lepton transverse momentum, P{sub T}, on M{sub top}. A maximum likelihood fit to the data yields a measured mass M{sub top} = 176.9 {+-} 8.0{sub stat} {+-} 2.7{sub syst} GeV/c{sup 2}. In this measurement, the contribution by the jet energy scale uncertainty to the systematic error is negligible. The result provides an important consistency test for other M{sub top} measurements where explicit use of the jet energy is made for deriving the top quark mass.
Date: January 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type: Article
System: The UNT Digital Library
Measurements of Direct CP Violating Asymmetries in Charmless Decays of Strange Bottom Mesons and Bottom Baryons (open access)

Measurements of Direct CP Violating Asymmetries in Charmless Decays of Strange Bottom Mesons and Bottom Baryons

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb{sup -1} of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A{sub CP}(B{sub s}{sup 0} {yields} K{sup -}{pi}{sup +}) = +0.39 {+-} 0.15 (stat) {+-} 0.08 (syst), and botton baryons, A{sub CP}({Lambda}{sub b}{sup 0} {yields} p{pi}{sup -}) = + 0.03 {+-} 0.17 (stat) {+-} 0.05 (syst) and A{sub CP} ({Lambda}{sub b}{sup 0} {yields} pK{sup -}) = +0.37 {+-} 0.17 (stat) {+-} 0.03 (syst). In addition, they measure CP violation in B{sup 0} {yields} K{sup +}{pi}{sup -} decays with 3.5{sigma} significance, A{sub CP} (B{sup 0} {yields} K{sup +}{pi}{sup -}) = -0.086 {+-} 0.023 (stat) {+-} 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B{sub s}{sup 0} {yields} K{sup +}K{sup -} and B{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays are also updated.
Date: March 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type: Article
System: The UNT Digital Library
First Measurement of the Angular Coefficients of Drell-Yan $e^{+}e^{-}$ pairs in the Z Mass Region from $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV (open access)

First Measurement of the Angular Coefficients of Drell-Yan $e^{+}e^{-}$ pairs in the Z Mass Region from $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV

We report on the first measurement of the angular distributions of final state electrons in p{bar p} {yields} {gamma}*/Z {yields} e{sup +}e{sup -} + X events produced in the Z boson mass region at {radical}s = 1.96 TeV. The data sample collected by the CDF II detector for this result corresponds to 2.1 fb{sup -1} of integrated luminosity. The angular distributions are studied as a function of the transverse momentum of the electron-positron pair and show good agreement with the Lam-Tung relation, consistent with a spin-1 description of the gluon, and demonstrate that at high values of the transverse momentum, Z bosons are produced via quark anti-quark annihilation and quark-gluon Compton processes.
Date: March 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S. et al.
Object Type: Article
System: The UNT Digital Library
Combined CDF and D0 Upper Limits on Standard Model Higgs Boson Production with up to 8.2 fb$^{-1}$ of Data (open access)

Combined CDF and D0 Upper Limits on Standard Model Higgs Boson Production with up to 8.2 fb$^{-1}$ of Data

We combine results from CDF and D0's direct searches for the standard model (SM) Higgs boson (H) produced in p{bar p} collisions at the Fermilab Tevatron at {radical}s = 1.96 TeV. The results presented here include those channels which are most sensitive to Higgs bosons with mass between 130 and 200 GeV/c{sup 2}, namely searches targeted at Higgs boson decays to W{sup +}W{sup -}, although acceptance for decays into {tau}{sup |+} {tau}{sup -} and {gamma}{gamma} is included. Compared to the previous Tevatron Higgs search combination, more data have been added and the analyses have been improved to gain sensitivity. We use the MSTW08 parton distribution functions and the latest gg {yields} H theoretical cross section predictions when testing for the presence of a SM Higgs boson. With up to 7.1 fb{sup -1} of data analyzed at CDF, and up to 8.2 fb{sup -1} at D0, the 95% C.L. upper limits on Higgs boson production is a factor of 0.54 times the SM cross section for a Higgs boson mass of 165 GeV/c{sup 2}. We exclude at the 95% C.L. the region 158 < m{sub H} < 173 GeV/c{sup 2}.
Date: March 1, 2011
Creator: Aaltonen, T.; Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M. et al.
Object Type: Article
System: The UNT Digital Library