553 research outputs found
Measurement of the production cross section of jets in association with a Z boson in pp collisions at √s=7 TeV with the ATLAS detector
Measurements of the production of jets of particles in association with a Z boson in pp collisions at s√=7 TeV are presented, using data corresponding to an integrated luminosity of 4.6 fb−1 collected by the ATLAS experiment at the Large Hadron Collider. Inclusive and differential jet cross sections in Z events, with Z decaying into electron or muon pairs, are measured for jets with transverse momentum p T > 30 GeV and rapidity |y| < 4.4. The results are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements supplemented by parton showers
Measurement of the differential cross-section of B + meson production in pp collisions at √s=7 TeV at ATLAS
The production cross-section of B + mesons is measured as a function of transverse momentum p T and rapidity y in proton-proton collisions at centre-of-mass energy s√=7 TeV, using 2.4 fb−1 of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < p T < 120 GeV and |y| < 2.25, are compared to next-to-leading-order theoretical predictions
Dynamics of isolated-photon plus jet production in pp collisions at √s=7 TeV with the ATLAS detector
The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb−1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle
Measurement of jet shapes in top-quark pair events at √s =7 TeV using the ATLAS detector
A measurement of jet shapes in top-quark pair events using 1.8 fb−1 of √s=7 TeV pp collision data recorded by the ATLAS detector at the LHC is presented. Samples of top-quark pair events are selected in both the single-lepton and dilepton final states. The differential and integrated shapes of the jets initiated by bottom-quarks from the top-quark decays are compared with those of the jets originated by light-quarks from the hadronic W-boson decays W→qq¯′ in the single-lepton channel. The light-quark jets are found to have a narrower distribution of the momentum flow inside the jet area than b-quark jets
Completing genotyping of composite germplasm set of sorghum
This project was designed to establish a composite germplasm set of circa 3000
accessions of wild and cultivated sorghum, determine the population structure of this
using approximately 50 SSR marker loci distributed across all 10 linkage groups of the
genome of cultivated Sorghum bicolor, and based on this information develop a reference
germplasm set of sorghum for use in allele mining and linkage disequilibrium mapping.
This was completed in 2007. Due to difficulties in getting the required genome coverage
with publicly available SSR markers, additional markers were developed and an
additional set of 40 of these have been used in 2008 to validate the population structure of
the sorghum reference germplasm set
Current Status And Strategy For Promoting Hybrid Sorghum And Pearl Millet Technology
4.1 Sorghum (Sorghum bicolor) and millets are important source8 of
food, feed and fodder in the Asia-Pacific region. Several millets are
grown, with the predominant species including proso millet (Panicum
miliaceum) in the former USSR, foxtail millet (Setaria italica) in
China, finger millet (Eleunine' coracana) in Nepal, and pearl millet
(Pennineturn glaucum) in India, Pakistan, and Yemen (Rachie, 1975) . In
this region, sorghum and pearl millet grain crops are most important in
economies of the large semi-arid tracts of the Indian sub-continent.
The use of these grass species for fodder, especially sorghum and
sorghum-sudangrass hybrids, is much more widely distributed. In
climates where their maturing grains are not exposed to high humidity
and/or rainfall, ,these cereals are important sources of carbohydrates
in human diets, especially in rural areas. In these areas, stover from
sorghum and pearl millet grain crops is often an important source of
dry season maintenance rations for livestock. In parts of the region
having higher rainfall or higher humidity, and in areas where prices of
other grains are subsidized, food use of sorghum and millets is
limited
Measurement of the azimuthal angle dependence of inclusive jet yields in Pb+Pb collisions at √sNN=2.76 TeV with the ATLAS detector
Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Δϕ, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Δϕ dependence of jet yields in 0.14 nb-1 of √sNN=2.76 TeV Pb+Pb collisions at the LHC for jet transverse momenta pT>45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Δϕ was characterized by the parameter, v2jet, and the ratio of out-of-plane (Δϕ∼π/2) to in-plane (Δϕ∼0) yields. Nonzero v2jet values were measured in all centrality bins for pT<160 GeV. The jet yields are observed to vary by as much as 20% between in-plane and out-of-plane directions
Measurement of the production cross section of prompt J/ψ mesons in association with a W± boson in pp collisions at p s = 7 TeV with the ATLAS detector
The process pp → W±J/ψ provides a powerful probe of the production mechanism of charmonium in hadronic collisions, and is also sensitive to multiple parton interactions in the colliding protons. Using the 2011 ATLAS dataset of 4.5 fb-1 of p s = 7TeV pp collisions at the LHC, the first observation is made of the production of W± + prompt J/ events in hadronic collisions, using W± → μ and J/ψ → μ+μ-. A yield of 27.4±7.5 -6.5 W± + prompt J/ψ events is observed, with a statistical significance of 5.1. The production rate as a ratio to the inclusive W± boson production rate is measured, and the double parton scattering contribution to the cross section is estimated
Search for direct third-generation squark pair production in final states with missing transverse momentum and two b-jets in √s=8 TeV pp collisions with the ATLAS detector
The results of a search for pair production of supersymmetric partners of the Standard Model third-generation quarks are reported. This search uses 20.1 fb−1 of pp collisions at √s=8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The lightest bottom and top squarks ( b˜1 and t˜1 respectively) are searched for in a final state with large missing transverse momentum and two jets identified as originating from b-quarks. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the visible cross section for processes beyond the Standard Model. Exclusion limits at the 95 % confidence level on the masses of the third-generation squarks are derived in phenomenological supersymmetric R-parity-conserving models in which either the bottom or the top squark is the lightest squark. The b˜1 is assumed to decay via b˜1→b∼χ01 and the t˜1 via t˜1→b∼χ1± , with undetectable products of the subsequent decay of the ∼χ1± due to the small mass splitting between the ∼χ1± and the ∼χ01
Diversity analysis of 3365 sorghums in the GCP composite germplasm set based on allelic variation at 41 SSR loci
The GCP Global Composite Germplasm Collection of 3372 wild and
cultivated sorghums includes 280 elite breeding lines and improved
cultivars, 250 Chinese germplasm lines to be provided by CAAS, 64
wild accessions, and >3000 landrace accessions selected from
previously defined core collections, for resistance/tolerance to
production constraints, and/or for variation in other traits. A set of 48
sorghum SSR markers distributed across all ten linkage groups was
chosen following preliminary analysis of 48 diverse genotypes with
104 available SSRs complemented by additional SSRs from CIRAD
and ICRISAT. Diversity analysis was performed on 3367 accessions
genotyped with 41 SSRs by CIRAD and ICRISAT.. Breeding lines
and wild accessions clustered separately from landraces, which
exhibited structure explainable by geographic origin. Landrace
population substructure was further characterized within racial
groups (five basic races and ten hybrid races). Race bicolor showed
little evidence of population structure, congruent with it being the
original domesticate. Race kafir (largely from Southern Africa) was
distinct. Accessions of the durra, caudatum and guinea races each
formed four distinct geographic subgroups. The guinea race
margaritiferum group formed its own cluster, suggesting
independent domestication. Intermediate races behaved similarly. A
reference subset of 384 accessions was then defined for allele
mining
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