We describe an analysis comparing the p (p) over bar elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM ...Collaboration at 2.76, 7, 8, and 13 TeVusing a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of root s = 1.96 TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4s level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4s and 4.6s. The combined significance is larger than 5 sigma and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound.
We present the observation of doubly-produced $J/\psi$ mesons with the D0 detector at Fermilab in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. The production cross section for both singly and ...doubly-produced $J/\psi$ mesons is measured using a sample with an integrated luminosity of 8.1~fb$^{-1}$. For the first time, the double $J/\psi$ production cross section is separated into contributions due to single and double parton scatterings. Using these measurements, we determine the effective cross section \sigteff, a parameter characterizing an effective spatial area of the parton-parton interactions and related to the parton spatial density inside the nucleon.
Zinc oxide, a transparent conducting oxide, has been synthesized in a novel route by application of continuous and pulsed mode ultrasonication. The powders prepared in this method are found to be ...nano particles of 24 and 20
nm respectively. The behaviour of two powders is found to be different when X-ray diffraction, photoluminescence, and Fourier transform infrared spectra were recorded. The thermo luminescence behaviour was also found to be different. It has been possible to incorporate H ion into the system by sonication process. Surface states created by sonication process are found to influence the photo and thermo luminescence of the system.
Thin films of Ni1−xZnxO with different composition (x=0, 0.01, 0.05 and 0.10) were successfully fabricated on glass substrates using spray pyrolysis technique. The as-prepared films were further ...annealed at 623K in room atmosphere for 2h. The evolution of their structural, morphological, electrical and optical properties with annealing temperature was investigated. The result reveals that the annealing of the films leads to improved surface morphology and better crystallinity. The prepared films displayed increase in conductivity followed by decrease in band gap with increase in doping concentration. However, the effect is more significant in case of annealed films, where the average transparency shows an increase of about 10% over the as prepared thin films. The red-shift of the optical band gap is due to the deep states in the band gap. The increase in density of states has been confirmed by variable range hoping (VRH) mechanism. The activation energy was found to be decreased when Zn concentration increased. Added to this the dielectric function of thin films and their spectral variation has been tentatively discussed.
Time-series observations were conducted off Visakhapatnam, central west coast of Bay of Bengal, from October 2007 to April 2009 to examine the influence of physical and atmospheric processes on water ...column nutrients biogeochemistry. The thermal structure displayed inversions of 0.5 to 1.0° C during winter and were weaker in summer. The water column was vertically stratified during the entire study period and was stronger during October–November 2007 and August–December 2008 compared to other study periods. High concentrations of chlorophyll-a and nutrients were associated with the extreme atmospheric events. The strong relationship of nutrients with salinity indicates that physical processes, such as circulation, mixing and river discharge, have a significant control on phytoplankton blooms in the coastal Bay of Bengal. Phosphate seems to be a controlling nutrient during winter whereas availability of light and suspended matter limits production in summer. Formation of low oxygen conditions were observed in the bottom waters due to enhanced primary production by extreme atmospheric events; however, re-oxygenation of bottom waters through sinking of oxygen-rich surface waters by a warm core (anticyclonic) eddy led to its near recovery. This study reveals that atmospheric and physical processes have significant impacts on the water column biogeochemistry in the coastal Bay of Bengal.
Sonochemical synthesis of nitrogen doped zinc oxide (ZnO:N) nanorods using acetate and nitrate of the starting materials is reported. X-ray diffraction studies reveal the formation of hexagonal ...wurtzite phase of ZnO in both the cases whereas the crystallite size is found to be greater in acetate route. Precursor dependent growth process is observed as the time period for precipitation is found to be different with different starting materials. Electron microscopic studies show the formation of rod like structures of ZnO and ZnO:N in both acetate and nitrate routes. But, high aspect ratio and uniformity in the morphology of ZnO:N nanorods is observed in acetate route. High resolution images and selected area diffraction patterns of ZnO:N illustrate the nanorods to be c-axis oriented in both the cases. But in nitrate medium, the growth along 0001 direction is affected due to the adsorption of NO
3
−
ions onto polar Zn
2+
surface leading to smaller length of the nanorods. FTIR studies also support these results showing the existence of sharp N–O symmetric stretching in ZnO:N in nitrate route. Photoluminescence (PL) measurements show red shift of excitonic emission band for ZnO in acetate route.
Abstract Purpose To compare the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) with that of multiphase computed tomography (CT) in the evaluation of tumor response to transarterial ...chemoembolization (TACE) of hepatocellular carcinoma (HCC). Material and methods Fifty patients (41 men, 9 women; mean age, 53 years ± 12.5 SD) with a total of 70 HCCs (mean size, 5 cm ± 3 SD) were evaluated. Post-TACE therapeutic assessment of HCC was done at 4 weeks. Patients with TACE done earlier and reporting with suspicion for recurrence were also included. Patients with hepatic masses seen on ultrasound were enrolled and subjected to CEUS, multiphase CT and magnetic resonance imaging (MRI). Hyperenhancing area at the tumor site on arterial phase of CEUS/multiphase CT/MRI was termed as residual disease (RD), the patterns of which were described on CEUS. Diagnostic accuracies of CEUS and MPCT were compared to that of MRI that was used as the reference standard. Results CEUS detected RD in 43/70 HCCs (61%). RD had a heterogeneous pattern in 22/43 HCCs (51%). Sensitivities of CEUS and multiphase CT were 94% (34/36; 95% CI: 81–99%) and 50% (18/36; 95% CI: 33–67%) respectively. Significant difference in sensitivity was found between CEUS and multiphase CT ( P = 0.0001). CEUS and multiphase CT had 100% specificity (95% CI: 83–100%). Conclusion CEUS is a useful technique for detecting RD in HCC after TACE. For long term surveillance, CEUS should be complemented with multiphase CT/MRI for a comprehensive evaluation.
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