2,372 research outputs found
Examining CP Symmetry in Strange Baryon Decays
Non-conservation of CP symmetry can manisfest itself in non-leptonic hyperon
decays as a difference in the decay parameter between the strange-baryon decay
and its charge conjugate. By comparing the decay distribution in the
helicity frame for the decay sequence , with that of decay, E756 at Fermilab did not
observe any CP-odd effect at the level. The status of a follow-up
experiment, HyperCP (FNAL E871), to search for CP violation in charged
decay with a sensitivity of is also presented.Comment: 9 pages, 4 figures, invited talk presented at the Third International
Conference on B Physics and CP Violation, 3-7 Dec 1999, Taipei, Taiwa
The Radon Monitoring System in Daya Bay Reactor Neutrino Experiment
We developed a highly sensitive, reliable and portable automatic system
(H) to monitor the radon concentration of the underground experimental
halls of the Daya Bay Reactor Neutrino Experiment. H is able to measure
radon concentration with a statistical error less than 10\% in a 1-hour
measurement of dehumidified air (R.H. 5\% at 25C) with radon
concentration as low as 50 Bq/m. This is achieved by using a large radon
progeny collection chamber, semiconductor -particle detector with high
energy resolution, improved electronics and software. The integrated radon
monitoring system is highly customizable to operate in different run modes at
scheduled times and can be controlled remotely to sample radon in ambient air
or in water from the water pools where the antineutrino detectors are being
housed. The radon monitoring system has been running in the three experimental
halls of the Daya Bay Reactor Neutrino Experiment since November 2013
Further investigation on chaos of real digital filters
This Letter displays, via the numerical simulation of a real digital filter, that a finite-state machine may behave in a near-chaotic way even when its corresponding infinite-state machine does not exhibit chaotic behavior
Measurement of Cosmic-ray Muons and Muon-induced Neutrons in the Aberdeen Tunnel Underground Laboratory
We have measured the muon flux and production rate of muon-induced neutrons
at a depth of 611 m water equivalent. Our apparatus comprises three layers of
crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray
muons and 760 L of gadolinium-doped liquid scintillator for producing and
detecting neutrons. The vertical muon intensity was measured to be cmssr. The yield of
muon-induced neutrons in the liquid scintillator was determined to be
neutrons/(gcm). A fit to the recently measured neutron
yields at different depths gave a mean muon energy dependence of for liquid-scintillator targets.Comment: 14 pages, 17 figures, 3 table
White Paper: Measuring the Neutrino Mass Hierarchy
This white paper is a condensation of a report by a committee appointed
jointly by the Nuclear Science and Physics Divisions at Lawrence Berkeley
National Laboratory (LBNL). The goal of this study was to identify the most
promising technique(s) for resolving the neutrino mass hierarchy. For the most
part, we have relied on calculations and simulations presented by the
proponents of the various experiments. We have included evaluations of the
opportunities and challenges for these experiments based on what is available
already in the literature.Comment: White paper prepared for Snowmass-201
LArPix: Demonstration of low-power 3D pixelated charge readout for liquid argon time projection chambers
We report the demonstration of a low-power pixelated readout system designed
for three-dimensional ionization charge detection and digital readout of liquid
argon time projection chambers (LArTPCs). Unambiguous 3D charge readout was
achieved using a custom-designed system-on-a-chip ASIC (LArPix) to uniquely
instrument each pad in a pixelated array of charge-collection pads. The LArPix
ASIC, manufactured in 180 nm bulk CMOS, provides 32 channels of
charge-sensitive amplification with self-triggered digitization and multiplexed
readout at temperatures from 80 K to 300 K. Using an 832-channel LArPix-based
readout system with 3 mm spacing between pads, we demonstrated low-noise
(500 e RMS equivalent noise charge) and very low-power (100
W/channel) ionization signal detection and readout. The readout was used
to successfully measure the three-dimensional ionization distributions of
cosmic rays passing through a LArTPC, free from the ambiguities of existing
projective techniques. The system design relies on standard printed circuit
board manufacturing techniques, enabling scalable and low-cost production of
large-area readout systems using common commercial facilities. This
demonstration overcomes a critical technical obstacle for operation of LArTPCs
in high-occupancy environments, such as the near detector site of the Deep
Underground Neutrino Experiment (DUNE).Comment: 19 pages, 10 figures, 1 ancillary animation. V3 includes minor
revisions based on referee comment
The S-wave \Lambda\pi phase shift is not large
We study the strong interaction S-wave \Lambda\pi phase shift in the region
of the \Xi mass in the framework of a relativistic chiral unitary approach
based on coupled channels. All parameters have been previously determined in a
fit to strangeness S= -1 S-wave kaon-nucleon data. We find 0^\circ \le \delta_0
\le 1.1^\circ in agreement with previous chiral perturbation theory
calculations (or extensions thereof). We also discuss why a recent coupled
channel K-matrix calculation gives a result for \delta_0 that is negative and
much bigger in magnitude. We argue why that value should not be trusted.Comment: 3 pages, REVTe
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