Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ROOT”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Search for neutral MSSM Higgs bosons decaying to tau(+)tau(-) pairs in proton-proton collisions root s=7 TeV with the ATLAS detector

A search for neutral Higgs bosons decaying to pairs of {tau} leptons with the ATLAS detector at the LHC is presented. The analysis is based on proton-proton collisions at a center-of-mass energy of 7 TeV, recorded in 2010 and corresponding to an integrated luminosity of 36 pb{sup -1}. After signal selection, 276 events are observed in this data sample. The observed number of events is consistent with the total expected background of 269 {+-} 36 events. Exclusion limits at the 95% confidence level are derived for the production cross section of a generic Higgs boson {phi} as a function of the Higgs boson mass and for A/H/h production in the Minimal Supersymmetric Standard Model (MSSM) as a function of the parameters m{sub A} and tan {beta}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Search for new phenomena with the monojet and missing transverse momentum signature using the ATLAS detector in root s=7 TeV proton-proton collisions

A search for new phenomena in events featuring a high energy jet and large missing transverse momentum in proton-proton collisions at {radical}s = 7 TeV is presented using a dataset corresponding to an integrated luminosity of 33 pb{sup -1} recorded with the ATLAS detector at the Large Hadron Collider. The number of observed events is consistent with the Standard Model prediction. This result is interpreted in terms of limits on a model of Large Extra Dimensions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Model-independent measurement of t-channel single top quark production in p(p)over-bar collisions at,root s=1.96 TeV

We present a model-independent measurement of t-channel electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. Using 5.4 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of b quarks, we measure a cross section {sigma}(p{bar p} {yields} tqb + X) = 2.90 {+-} 0.59 (stat + syst) pb for a top quark mass of 172.5 GeV. The probability of the background to fluctuate and produce a signal as large as the one observed is 1.6 x 10{sup -8}, corresponding to a significance of 5.5 standard deviations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at root s=7 TeV using 35 pb(-1) of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy {radical}s = 7 TeV is presented. The measurement covers the pseudorapidity ranges |{eta}| < 1.37 and 1.52 {le} |{eta}| < 2.37 in the transverse energy range 45 {le} E{sub T} < 400 GeV. The results are based on an integrated luminosity of 35 pb{sup -1}, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Measurement of the cross section for the production of a W boson in association with b-jets in pp collisions at root s=7 TeV with the ATLAS detector

A measurement is presented of the cross section for the production of a W boson with one or two jets, of which at least one must be a b-jet, in pp collisions at {radical}s = 7 TeV. Production via top decay is not included in the signal definition. The measurement is based on 35 pb{sup -1} of data collected with the ATLAS detector at the LHC. The W + b-jet cross section is defined for jets reconstructed with the anti-kt clustering algorithm with transverse momentum above 25 GeV and rapidity within {+-}2.1. The b-jets are identified by reconstructing secondary vertices. The fiducial cross section is measured both for the electron and muon decay channel of the W boson and is found to be 10.2 {+-} 1.9(stat) {+-} 2.6(syst) pb for one lepton flavour. The results are compared with next-to-leading order QCD calculations, which predict a cross section smaller than, though consistent with, the measured value.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Search for Higgs bosons decaying to tau(+)tau(-) pairs in p(p)over-bar collisions at root s=1.96 TeV

We present a search for the production of neutral Higgs bosons decaying into {tau}{sup +}{tau}{sup -} pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb{sup -1}, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into {tau}{sup +}{tau}{sup -} pairs, and we interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Measurements of the electron and muon inclusive cross-sections in proton-proton collisions at root s=7 TeV with the ATLAS detector

This Letter presents measurements of the differential cross-sections for inclusive electron and muon production in proton-proton collisions at a centre-of-mass energy of {radical}s = 7 TeV, using data collected by the ATLAS detector at the LHC. The muon cross-section is measured as a function of pT in the range 4 < pT < 100 GeV and within pseudorapidity |{eta}| < 2.5. In addition the electron and muon cross-sections are measured in the range 7 < pT < 26 GeV and within |{eta}| < 2.0, excluding 1.37 < |{eta}| < 1.52. Integrated luminosities of 1.3 pb{sup -1} and 1.4 pb{sup -1} are used for the electron and muon measurements, respectively. After subtraction of the W/Z/{gamma}{sm_bullet} contribution, the differential cross-sections are found to be in good agreement with theoretical predictions for heavy-flavour production obtained from Fixed Order NLO calculations with NLL high-pT resummation, and to be sensitive to the effects of NLL resummation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Measurement of the top quark pair production cross section in pp collisions at root s=7 TeV in dilepton final states with ATLAS

A measurement of the production cross section of top quark pairs (t{bar t}) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of 35 pb{sup -1}, a t{bar t} production cross section {sigma}{sub t{bar t}} = 177 {+-} 20(stat.) {+-} 14(syst.) {+-} 7(lum.) pb is measured for an assumed top quark mass of mt = 172.5 GeV. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Search for anomalous Wtb couplings in single top quark production in p(p)over-bar collisions at root s=1.96 TeV

We present new direct constraints on a general Wtb interaction using data corresponding to an integrated luminosity of 5.4 fb{sup -1} collected by the D0 detector at the Tevatron p{bar p} collider. The standard model provides a purely left-handed vector coupling at the Wtb vertex, while the most general, lowest dimension Lagrangian allows right-handed vector and left- or right-handed tensor couplings as well. We obtain precise limits on these anomalous couplings by comparing the data to the expectations from different assumptions on the Wtb coupling.

43 PARTICLE ACCELERATORS↗