105 research outputs found
Mechanical vibrations of pendant liquid droplets
A simple optical deflection technique was used to monitor the vibrations of microlitre pendant droplets of deuterium oxide, formamide, and 1,1,2,2-tetrabromoethane. Droplets of different volumes of each liquid were suspended from the end of a microlitre pipette and vibrated using a small puff of nitrogen gas. A laser was passed through the droplets and the scattered light was collected using a photodiode. Vibration of the droplets resulted in the motion of the scattered beam and time-dependent intensity variations were recorded using the photodiode. These time- dependent variations were Fourier transformed and the frequencies and widths of the mechanical droplet resonances were extracted. A simple model of vibrations in pendant/sessile drops was used to relate these parameters to the surface tension, density and viscosity of the liquid droplets. The surface tension values obtained from this method were found to be in good agreement with results obtained using the standard pendant drop technique. Damping of capillary waves on pendant drops was shown to be similar to that observed for deep liquid baths and the kinematic viscosities obtained were in agreement with literature values for all three liquids studied
Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam
Neutral current single pi0 production induced by neutrinos with a mean energy
of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near
detector of the K2K long baseline neutrino experiment. The cross section for
this process relative to the total charged current cross section is measured to
be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of
produced pi0s is measured and is found to be in good agreement with an
expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.
Calibration of Super-Kamiokande Using an Electron Linac
In order to calibrate the Super-Kamiokande experiment for solar neutrino
measurements, a linear accelerator (LINAC) for electrons was installed at the
detector. LINAC data were taken at various positions in the detector volume,
tracking the detector response in the variables relevant to solar neutrino
analysis. In particular, the absolute energy scale is now known with less than
1 percent uncertainty.Comment: 24 pages, 16 figures, Submitted to NIM
Measurement of radon concentrations at Super-Kamiokande
Radioactivity from radon is a major background for observing solar neutrinos
at Super-Kamiokande. In this paper, we describe the measurement of radon
concentrations at Super-Kamiokande, the method of radon reduction, and the
radon monitoring system. The measurement shows that the current low-energy
event rate between 5.0 MeV and 6.5 MeV implies a radon concentration in the
Super-Kamiokande water of less than 1.4 mBq/m.Comment: 11 pages, 4 figure
Search for Neutral Q-balls in Super-Kamiokande II
A search for Q-balls induced groups of successive contained events has been
carried out in Super-Kamiokande II with 541.7 days of live time.
Neutral Q-balls would emit pions when colliding with nuclei, generating a
signal of successive contained pion events along a track. No candidate for
successive contained event groups has been found in Super-Kamiokande II, so
upper limits on the possible flux of such Q-balls have been obtained.Comment: 5 pages, 5 figures, Submitted to Phys. Lett.
Search for nucleon decay into charged antilepton plus meson in 0.316 megaton . years exposure of the Super-Kamiokande water Cherenkov detector
We have searched for proton decays into a charged antilepton (e+, μ+) plus a meson (η, ρ0, ω) and for neutron decays into a charged antilepton (e+, μ+) plus a meson (π−, ρ−) using Super-Kamiokande I-IV data, corresponding to 0.316 megaton⋅years of exposure. This measurement updates the previous published result by using 2.26 times more data and improved analysis methods. No significant evidence for nucleon decay is observed and lower limits on the partial lifetime of the nucleon are obtained. The limits range from 3×1031 to 1×1034 years at 90% confidence level, depending on the decay mode
Search for Boosted Dark Matter Interacting with Electrons in Super-Kamiokande
A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search
for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible
energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is
observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center
and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced
from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter
from the Galactic center or the Sun interacting in a terrestrial detector
Effect of maturation on carbazole distributions as revealed by the hydrous pyrolysis of an organic-sulphur-rich source rock (Ghareb Formation, Jordan)
Hydrous pyrolysis experiments were performed on the Ghareb Formation (Upper Cretaceous, Jordan), a carbonate- and organic-rich (TOC 19.6%) source rock, using a temperature range of 200 to 360°C (72 h). The original sediment contains only low amounts of carbazoles, (maximum 2.2 g/g bitumen for 1-methylcarbazole). With increasing thermal maturation, intense generation begins at temperatures only in excess of 300°C, reaching a maximum at 360°C. Likewise, during natural maturation, generation occurs at later stages of maturity (e.g. for Tithonian source rocks at >0.81% Rr and for Posidonia Shale at >0.88% Rr). Some isomeric changes during hydrous pyrolysis do not resemble those in nature whereas others do. The relative abundances of selected C1- and C2-alkylcarbazoles on ternary diagrams reveal differences, whereas the benzo[a]carbazole/benzo[a]carbazole+benzo[c]carbazole ratio is closely similar. The latter result supports the contention that maturation plays a key role in controlling carbazole distributions in source rocks. However, the results for alkylcarbazoles, especially the C2-carbazoles, are not easy to interpret
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