4,865 research outputs found
Low-energy electronic recoil in xenon detectors by solar neutrinos
Low-energy electronic recoil caused by solar neutrinos in multi-ton xenon
detectors is an important subject not only because it is a source of the
irreducible background for direct searches of weakly-interacting massive
particles (WIMPs), but also because it provides a viable way to measure the
solar and neutrinos at the precision level of current
standard solar model predictions. In this work we perform
many-body calculations for the structure, photoionization, and
neutrino-ionization of xenon. It is found that the atomic binding effect yields
a sizable suppression to the neutrino-electron scattering cross section at low
recoil energies. Compared with the previous calculation based on the free
electron picture, our calculated event rate of electronic recoil in the same
detector configuration is reduced by about . We present in this paper the
electronic recoil rate spectrum in the energy window of 100 eV - 30 keV with
the standard per ton per year normalization for xenon detectors, and discuss
its implication for low energy solar neutrino detection (as the signal) and
WIMP search (as a source of background).Comment: 12 pages, 3 figure
Performance evaluation of real-time indoor positioning with active RFID and ZigBee-based WSN systems
This study measures the accuracy of two radio signal-based positioning methods to track targets in an indoor environment using radio frequency identification (RFID) and a wireless sensor network (WSN), the advantages and disadvantages of which are compared, analyzed, and discussed. We propose a specific configuration to perform measurements in a real environment using various positioning algorithms. The experimental results show that the number and the quality of the reference tags influence the accuracy of positioning when using RFID devices. Although WSN devices require fewer sensors, the unit price of sensors is comparatively high. In addition, adjusting the antenna angle achieves a stronger received signal strength indicator variation when using RFID devices. For WSN devices, the key is to avoid interference between sensors because it causes large errors when estimating the distance between 2 points. The proposed positioning methods are suitable for patrol systems, and can be employed to obtain security service personnel location data and confirm their patrol routes. This study adopts active RFID technology and nano real-time positioning WSN technology to test the indoor positioning accuracy of these technologies and related system construction issues. The findings provide a reference for future research on indoor positioning method selection
Split representation in celestial holography
We develop a split representation for celestial amplitudes in celestial
holography, by cutting internal lines of Feynman diagrams in Minkowski space.
More explicitly, the bulk-to-bulk propagators associated with the internal
lines are expressed as a product of two boundary-to-bulk propagators with a
coinciding boundary point integrated over the celestial sphere. Applying this
split representation, we compute the conformal partial wave and conformal block
expansions of celestial four-point functions of massless scalars and photons on
the Euclidean celestial sphere. In the -channel massless scalar amplitude,
we observe novel intermediate exchanges of staggered modules in the conformal
block expansion.Comment: 76 page
Measuring fraud in insurance industry: The case of automobile insurance in Taiwan
By conducting an extensive exploration on claim data, this paper attempts to investigate the fraud problem in Taiwan automobile physical damage insurance. Based on the different claim patterns between data in calendar year
and policy year, excess claims are significantly identified in the last month of policy year. Censored regression provides robust estimation concerning the sources of the fraud payment
Pneumoperitoneum caused by perforation of pyometra associated with a lost intrauterine device and perforated malignancy of the sigmoid colon
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