1,756 research outputs found
Selective, catalytic oxidation using hydrogen/oxygen mixtures with solutions of Iridium and Rhodium complexes
No full textSelective, homogeneous, catalytic oxidation of olefins using oxygen/hydrogen mixtures; oxygen atom transfer from an Iridium hydroperoxide
No full textAn iridium(III) hydride complex in solution catalyses the O 2-co-oxidation of cyclo-octene and H2 to cyclo-octanone and water, respectively, via a hydroperoxide intermediate
Pressure groups and government policy on education, 1800 - 1839.
No full textThis study examines the roles of the principal groups and individuals,
who, during the years 1800-1839, promoted the education of the poor
and pressurised governments with the notion that the state ought to
ac ept responsibility for the formation of a nationa1 system. Their
m tives were primarily religious, philanthropic or political with a
degree of self-interest in the desire to preserve order in society.
The religious interests are examined mainly through the work of
the British and Foreign Sch ol Society, which served the Dissenter
traditi ns, and the Nati nal S ciety which defended the prerogative of
the Establi h d Church t superintend the education of the people. The
tilitarians and Radicals were imp rtant for the practica1 expression
f their philos phical and political ideas led them to make a considerable
c ntributi n to the provision schools. They also had the inspiration
and organising ability of Jam s Mill and Francis Place.
The ideas of Robert Owen are considered because he was a pressure
figure for a few years, but his work also sowed the seeds of Co-operation
and w rking-cla s movements, which made an impact during the 1830's. As the
populati n slowly improved in standard of learning, the development of
Mechanics' Institutes, the Society for the Difflision of Useful Knowledge
and the foundation of University College are viewed as part of a strategy
for the general promotion of adult education1
The dominant personality of Henry Brougham is evident in much of
this study. He instituted the Charity Commissions in 1819, was spokesman
(iv)
for education in Parliament for many years, anj was a link between
the different groups because of his involvement in so many.
During the 1830's the new science of statistics emerged and the
Statistical Societies were important for their presentation of data
on education1 The existence of a National Board of Education in Ireland
after 1831 placed the province ahead of England and the influences
from this experiment, mediated to Parliament by Thomas Wyse and others,
all helped to pressurise the governments of the day, whose policy had
been to encourage voluntary effort and to avoid the imposition of central
administrative control
Measurement of the and production cross sections in multilepton final states using 3.2 fb of collisions at = 13 TeV with the ATLAS detector
No full textSee paper for full list of authors - 22 pages plus author list + cover page (40 pages total), 8 figures, 5 tables. Submitted to Eur. Phys. J. C. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2015-22/International audienceA measurement of the and production cross sections in final states with either two same-charge muons, or three or four leptons (electrons or muons) is presented. The analysis uses a data sample of proton-proton collisions at TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015, corresponding to a total integrated luminosity of 3.2 fb. The inclusive cross sections are extracted using likelihood fits to signal and control regions, resulting in pb and pb, in agreement with the Standard Model predictions
Search for top quark decays t → qH with H → γγ using the ATLAS detector
No full textA search is performed for flavour-changing neutral currents in the decay of a top quark to an up-type (c, u) quark and a Higgs boson, where the Higgs boson decays to two photons. The proton-proton collision data set used corresponds to 4.7 fb-1 at √ = 7TeV and 20.3fb-1 at √ = 8TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for in which one top quark decays to qH and the other decays to bW. Both the hadronic and the leptonic decay modes of the W boson are used. No significant signal is observed and an upper limit is set on the t → qH branching ratio of 0.79 at the 95% confidence level. The corresponding limit on the tqH coupling combination λtcH 2 + λtuH 2 is 0.17
Search for t t ¯ H / A → t t ¯ t t ¯ production in the multilepton final state in proton–proton collisions at s = 13 TeV with the ATLAS detector
No full textAbstract A search for a new heavy scalar or pseudo-scalar Higgs boson (H/A) produced in association with a pair of top quarks, with the Higgs boson decaying into a pair of top quarks (H/A → t t ¯ ) is reported. The search targets a final state with exactly two leptons with same-sign electric charges or at least three leptons. The analysed dataset corresponds to an integrated luminosity of 139 fb −1 of proton–proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Two multivariate classifiers are used to separate the signal from the background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of a type-II two-Higgs-doublet model. The observed (expected) upper limits at 95% confidence level on the t t ¯ H / A production cross-section times the branching ratio of H/A → t t ¯ range between 14 (10) fb and 6 (5) fb for a heavy Higgs boson with mass between 400 GeV and 1000 GeV, respectively. Assuming that only one particle, either the scalar H or the pseudo-scalar A, contributes to the t t ¯ t t ¯ final state, values of tan β below 1.2 or 0.5 are excluded for a mass of 400 GeV or 1000 GeV, respectively. These exclusion ranges increase to tan β below 1.6 or 0.6 when both particles are considered
Measurement of the top quark mass in the and channels using TeV ATLAS data
No full textThe top quark mass was measured in the channels and (lepton=) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton--proton centre-of-mass energy of TeV and correspond to an integrated luminosity of 4.6fb, The analysis uses a three-dimensional template technique which determines the top quark mass together with a global jet energy scale factor (JSF), and a relative -to-light-jet energy scale factor (bJSF), where the terms -jets and light-jets refer to jets originating from -quarks and -quarks or gluons, respectively. The analysis of the channel exploits a one-dimensional template method using the observable, defined as the average invariant mass of the two lepton--jet pairs in each event. The top quark mass is measured to be GeV, and GeV in the and channels, respectively. The combination of the two results yields GeV, with a total uncertainty of GeV
Measurement of the production cross section in the + jets final state in collisions at TeV using the ATLAS detector
No full textSee paper for full list of authors - 37 pages in total, author list starts at page 21, 2 figures, 6 tables, submitted to Phys. Rev. D, all figures and tables including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2015-18/International audienceA measurement of the inclusive production cross section in the final state using only the hadronic decays of the lepton is presented. The measurement is performed using 20.2 fb of proton-proton collision data recorded at a center-of-mass energy of TeV with the ATLAS detector at the Large Hadron Collider. The cross section is measured via a counting experiment by imposing a set of selection criteria on the identification and kinematic variables of the reconstructed particles and jets, and on event kinematic variables and characteristics. The production cross section is measured to be pb, which is in agreement with the measurements in other final states and the theoretical predictions at this center-of-mass energy
A search for resonances using lepton-plus-jets events in proton-proton collisions at TeV with the ATLAS detector
No full textSee paper for full list of authors – 36 pages plus author list + cover pages (53 pages total), 12 figures, 2 tables, submitted to JHEP, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2012-18/International audienceA search for new particles that decay into top quark pairs is reported. The search is performed with the ATLAS experiment at the LHC using an integrated luminosity of 20.3 fb of proton-proton collision data collected at a centre-of-mass energy of TeV. The lepton-plus-jets final state is used, where the top pair decays to , with one boson decaying leptonically and the other hadronically. The invariant mass spectrum of top quark pairs is examined for local excesses or deficits that are inconsistent with the Standard Model predictions. No evidence for a top quark pair resonance is found, and 95% confidence-level limits on the production rate are determined for massive states in benchmark models. The upper limits on the cross-section times branching ratio of a narrow boson decaying to top pairs range from 4.2 pb to 0.03 pb for resonance masses from 0.4 TeV to 3.0 TeV. A narrow leptophobic topcolour boson with mass below 1.8 TeV is excluded. Upper limits are set on the cross-section times branching ratio for a broad colour-octet resonance with 15% decaying to . These range from 2.5 pb to 0.03 pb for masses from 0.4 TeV to 3.0 TeV. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.2 TeV
Inclusive and differential cross-sections for dilepton t t ¯ production measured in s = 13 TeV pp collisions with the ATLAS detector
No full textAbstract Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs ( t t ¯ ) are measured using the full LHC Run 2 data sample collected with the ATLAS detector. The data were collected at a pp collision energy of s = 13 TeV and correspond to an integrated luminosity of 140 fb −1. The measurements use events containing an oppositely charged eμ pair and b-tagged jets. The results are compared with predictions from several Monte Carlo generators. While no prediction is found to be consistent with all distributions, a better agreement with measurements of the lepton p T distributions is obtained by reweighting the t t ¯ sample so as to reproduce the top-quark p T distribution from an NNLO calculation. The inclusive top-quark pair production cross-section is measured as well, both in a fiducial region and in the full phase-space. The total inclusive cross-section is found to be σ t t ¯ = 829 ± 1 stat ± 13 syst ± 8 lumi ± 2 beam pb , where the uncertainties are due to statistics, systematic effects, the integrated luminosity and the beam energy. This is in excellent agreement with the theoretical expectation
- …
