479 research outputs found
Rare Kaon Decay From E949 At BNL: K^+ -->pi^+ nunubar
In the first year of physics run, the E949 experiment at Brookhaven National
Laboratory has already collected kaons stopping in the
target. Additional evidence for the rare charged kaon decay
has been observed. Combined with previous results
from the E787 experiment, the branching ratio is measured to be
Br()=.Comment: 4pages. Submitted to 32nd International Conference on High-Energy
Physics (ICHEP04), Beijing, China, 16-22 Aug 200
Discovery potential for supernova relic neutrinos with slow liquid scintillator detectors
Detection of supernova relic neutrinos could provide key support for our
current understanding of stellar and cosmological evolution, and precise
measurements of these neutrinos could yield novel insights into the universe.
In this paper, we studied the detection potential of supernova relic neutrinos
using linear alkyl benzene (LAB) as a slow liquid scintillator. The linear
alkyl benzene features good separation of Cherenkov and scintillation lights,
thereby providing a new route for particle identification. We further addressed
key issues in current experiments, including (1) the charged current background
of atmospheric neutrinos in water Cherenkov detectors and (2) the neutral
current background of atmospheric neutrinos in typical liquid scintillator
detectors. A kiloton-scale LAB detector at Jinping with (10) years
of data could discover supernova relic neutrinos with a sensitivity comparable
to that of large-volume water Cherenkov detectors, typical liquid scintillator
detectors, and liquid argon detectors.Comment: 9 pages, 6 figure
Design, characterization, and sensitivity of the supernova trigger system at Daya Bay
Providing an early warning of galactic supernova explosions from neutrino
signals is important in studying supernova dynamics and neutrino physics. A
dedicated supernova trigger system has been designed and installed in the data
acquisition system at Daya Bay and integrated into the worldwide Supernova
Early Warning System (SNEWS). Daya Bay's unique feature of eight
identically-designed detectors deployed in three separate experimental halls
makes the trigger system naturally robust against cosmogenic backgrounds,
enabling a prompt analysis of online triggers and a tight control of the
false-alert rate. The trigger system is estimated to be fully sensitive to
1987A-type supernova bursts throughout most of the Milky Way. The significant
gain in sensitivity of the eight-detector configuration over a mass-equivalent
single detector is also estimated. The experience of this online trigger system
is applicable to future projects with spatially distributed detectors.Comment: 8 pages, 6 figures, to be submitted to Astroparticle Physic
Multiqubit entanglement due to quantum gravity
Quantum gravity between masses can produce entangled states in thought
experiments. We extend the experiments to tripartite case and construct states
equivalent to Greenberger- Horne-Zeilinger states and W states under stochastic
local operations and classical communication. The entanglement relates to the
evolution phases induced by gravitational interaction. When we involve more
masses in the experiments, multipartite entangled states can be constructed in
a similar way. We measure the degree of multipartite entanglement by
calculating the geometric measure. We describe the relationship between
geometric measure and the evolution phases. It helps in searching out the
states with robust entanglement.Comment: 17 pages,9 figure
Generalized integrated importance measure for system performance evaluation: application to a propeller plane system
The integrated importance measure (IIM) evaluates the rate of system performance change due to a component changing from one state to another. The IIM simply considers the scenarios where the transition rate of a component from one state to another is constant. This may contradict the assumption of the degradation, based on which system performance is degrading and therefore the transition rate may be increasing over time. The Weibull distribution describes the life of a component, which has been used in many different engineering applications to model complex data sets. This paper extends the IIM to a new importance measure that considers the scenarios where the transition rate of a component degrading from one state to another is a time-dependent function under the Weibull distribution. It considers the conditional probability distribution of a component sojourning at a state is the Weibull distribution, given the next state that component will jump to. The research on the new importance measure can identify the most important component during three different time periods of the system lifetime, which is corresponding to the characteristics of Weibull distributions. For illustration, the paper then derives some probabilistic properties and applies the extended importance measure to a real-world example (i.e., a propeller plane system)
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