126 research outputs found
D* Production in Deep Inelastic Scattering at HERA
This paper presents measurements of D^{*\pm} production in deep inelastic
scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The
data have been taken with the ZEUS detector at HERA. The decay channel
(+ c.c.) has been used in the study. The
cross section for inclusive D^{*\pm} production with
and is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region
{ GeV and }. Differential cross
sections as functions of p_T(D^{*\pm}), and are
compared with next-to-leading order QCD calculations based on the photon-gluon
fusion production mechanism. After an extrapolation of the cross section to the
full kinematic region in p_T(D^{*\pm}) and (D^{*\pm}), the charm
contribution to the proton structure function is
determined for Bjorken between 2 10 and 5 10.Comment: 17 pages including 4 figure
Observation of Scaling Violations in Scaled Momentum Distributions at HERA
Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of and using the ZEUS detector. The
evolution of the scaled momentum, , with in the range 10 to 1280
, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of .Comment: 21 pages including 4 figures, to be published in Physics Letters B.
Two references adde
Measurement of the dijet invariant mass cross section in proton anti-proton collisions at sqrt{s} = 1.96 TeV
The inclusive dijet production double differential cross section as a
function of the dijet invariant mass and of the largest absolute rapidity of
the two jets with the largest transverse momentum in an event is measured in
proton anti-proton collisions at sqrt{s} = 1.96 TeV using 0.7 fb^{-1}
integrated luminosity collected with the D0 detector at the Fermilab Tevatron
Collider. The measurement is performed in six rapidity regions up to a maximum
rapidity of 2.4. Next-to-leading order perturbative QCD predictions are found
to be in agreement with the data.Comment: Published in Phys. Lett. B, 693, (2010), 531-538, 8 pages, 2 figures,
6 table
Measurement of the cross section and limits on anomalous triple gauge couplings in collisions at = 1.96 TeV
We present a new measurement of the () cross section and limits on anomalous triple gauge couplings. Using 4.1
fb of integrated luminosity of collisions at TeV, we observe 34 candidate events with an estimated background of
events. We measure the production cross section to be
pb, in good agreement with the standard model
prediction. We find no evidence for anomalous couplings and set 95% C.L.
limits on the coupling parameters, and , in the HISZ parameterization for a TeV
form factor scale. These are the best limits to date obtained from the direct
measurement of the vertex.Comment: 8 pages, 7 figures, 2 table
Effects, Transfer, and Fate of RDX from Aged Soil in Plants and Worms
The objectives of this study were to provide data that can be used to predict exposure-based effects of RDX in aged soil on multiple endpoint organisms representing two trophic levels. These data can be used for defining criteria or reference values for environmental management and conducting specific risk assessment. Dose–response experiments formed the basis for the evaluation of toxic effects and transfer of contaminants from soil into two trophic levels. Long-term exposure tests were conducted to evaluate chronic, sublethal, toxicity and transfer of aged soil-based explosives, with RDX as main contaminant. In these tests, plants were exposed for 55 days in the greenhouse, biomass was determined and residues of explosives parent compounds and RDX metabolites were analyzed using HPLC techniques. Worms were exposed for 28 days (Eisenia fetida) and 42 days (Enchytraeus crypticus) in the laboratory, biomass and number were determined, and tissues were analyzed for explosives compounds. The plants tolerated concentrations up to 1540 mg RDX kg-1 soil-DW. Biomass of Lolium perenne was not significantly related to soil-RDX concentration, while biomass of Medicago sativa significantly increased. No screening benchmark for RDX in soil for plants was calculated, since concentrations up to 1540 mg kg-1 soil failed to reduce biomass by 20% as required for a LOEC. RDX, RDX-metabolite MNX, and accompanying HMX concentrations in plants were significantly related to concentrations in soil after 55 days of exposure (RDX: R2 = 0.77–0.89; MNX R2 = 0.53–0.77; HMX: R2 = 0.67–0.71). The average bioconcentration factors (BCF) were for RDX 17 in L. perenne and 37 in M. sativa, and for HMX 2 in L. perenne and 44 in M. sativa. The worms also tolerated concentrations up to 1540 mg RDX kg-1 soil-DW. Biomass of E. fetida adults decreased with soil-RDX concentration, and a LOEC of 1253 mg kg-1 soil-DW was estimated. RDX concentrations in E. fetida were significantly related to concentrations in soil after 28-day exposure (R2 = 0.88). The average BCF in E. fetida for RDX was 1. Because in response to exposure to RDX-contaminated soil the RDX concentrations in plants increased initially and decreased subsequently, while those in worms increased continuously, RDX in worm tissues may accumulate to higher concentrations than in plant tissues, regardless of the low average BCF for worms
Macro-encapsulation of heat storage phase-change materials for use in residential buildings. First quarterly progress report, September 29--December 29, 1976
Objectives are to assess the feasibility of macro-encapsulated PCM's for residential solar systems, to develop and evaluate such materials. Five PCM's have been selected from encapsulation studies. Encapsulated storage media were evaluated theoretically in storage beds with air and water as the heat transfer medium. Cylindrical, tetrahedral, and pillow shapes are being evaluated for the encapsulated PCM. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles
Macro-encapsulation of heat storage phase-change materials for use in residential buildings. Third quarterly progress report, March 29, 1977--June 29, 1977
Objectives are to assess the feasibility of macro-encapsulated PCMs for residential solar systems and to develop and evaluate such materials. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles. PCMs under study are Mg(NO/sub 3/)/sub 2/.6H/sub 2/O, naphthalene-benzoic acid eutectic, Mg(NO/sub 3/)/sub 2/.6H/sub 2/O-NH/sub 4/NO/sub 3/ eutectic, and CaCl/sub 2/.6H/sub 2/O. Compatibility studies between the PCMs and encapsulant materials are continuing. A test device has been constructed, and is ready for use
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