4,063 research outputs found
The system of EAS time analysis
The extensive air showers' (EAS) front shape, angle of incidence, disk thickness, particle distribution along the shower, on the delayed and EAS front advancing particles were determined. The suggested system of the EAS time analysis allows determination of the whole EAS longitudinal structure at the observation points. The information from the detectors is continuously recorded in the memory with the memory cell switching in 5 ns, this enables fixation of the moment of pulse input from the detector with an accuracy to + or - 2.5 ns. Along with the fast memory, a slow memory with the cell switching in 1 micron s is introduced in the system, this permits observation of relatively large time intervals with respect to the trigger pulse with an appropriately lower accuracy
Weak and Magnetic Inelastic Scattering of Antineutrinos on Atomic Electrons
Neutrino scattering on electrons is considered as a tool for laboratory
searches of the neutrino magnetic moment. We study inelastic
-scattering on electrons bound in the germanium (Z=32) and iodine
(Z=53) atoms for antineutrinos generated in a nuclear reactor core and also in
the Sr-Y and Pm artificial sources. Using the
relativistic Hartree-Fock-Dirac model, we calculate both the magnetic and weak
scattering cross sections for the recoil electron energy range of 1 to 100 keV
where a higher sensitivity to the neutrino magnetic moment could be achieved.
Particular attention is paid to the approximate procedure which allows us to
take into account the effects of atomic binding on the inelastic scattering
spectra in a simple way.Comment: 7 pages in LaTeX, 10 figures in P
Reactor monitoring and safeguards using antineutrino detectors
Nuclear reactors have served as the antineutrino source for many fundamental
physics experiments. The techniques developed by these experiments make it
possible to use these very weakly interacting particles for a practical
purpose. The large flux of antineutrinos that leaves a reactor carries
information about two quantities of interest for safeguards: the reactor power
and fissile inventory. Measurements made with antineutrino detectors could
therefore offer an alternative means for verifying the power history and
fissile inventory of a reactors, as part of International Atomic Energy Agency
(IAEA) and other reactor safeguards regimes. Several efforts to develop this
monitoring technique are underway across the globe.Comment: 6 pages, 4 figures, Proceedings of XXIII International Conference on
Neutrino Physics and Astrophysics (Neutrino 2008); v2: minor additions to
reference
Disruption of Particle Detector Electronics by Beam Generated EMI
The possibility that radio frequency beam generated electromagnetic interference (EMI) could disrupt the operation of particle detector electronics has been of some concern since the inception of short pulse electron colliders more than 30 years ago [1]. Some instances have been reported where this may have occurred but convincing evidence has not been available. This possibility is of concern for the International Linear Collider (ILC). We have conducted test beam studies demonstrating that electronics disruption does occur using the vertex detector electronics (VXD) from the SLD detector which took data at the SLC at SLAC. We present the results of those tests, and we describe the need for EMI standards for beam and detector instrumentation in the IR region at the ILC
Air ions induced aerosol sensing by eye-safe LIDAR
Low concentrations aerosols quantification is rather challenging for LIDAR
instruments due to eye-safety restrictions so high energy pulses cannot be
utilized to improve the sensitivity. Highly sensitive but eye-save LIDAR has
been developed for the quantification of the water droplet aerosol which was
induced by air ions. Few days sensing of aerosols in closed tunnel revealed a
strong correlation between air optical transparency (LIDAR measurements) and
concentrations of positive/negative ions (ion counter Sapphir 3-M). The
correlation coefficient was observed to be almost unity for the air
transparency signal and air ions unipolarity coefficient. High sensitivity of
the water droplet aerosol quantification makes the developed eye-safe LIDAR a
perspective instrument for space resolved measurements of the air ions
distribution. Space and time resolved measurements of air ions exhalation can
be a new instrument for tectonic activity study including new earthquake
forecasting indicators search
Neutrino oscillations and uncertainty relations
We show that coherent flavor neutrino states are produced (and detected) due
to the momentum-coordinate Heisenberg uncertainty relation. The Mandelstam-Tamm
time-energy uncertainty relation requires non-stationary neutrino states for
oscillations to happen and determines the time interval (propagation length)
which is necessary for that. We compare different approaches to neutrino
oscillations which are based on different physical assumptions but lead to the
same expression for the neutrino transition probability in standard neutrino
oscillation experiments. We show that a Moessbauer neutrino experiment could
allow to distinguish different approaches and we present arguments in favor of
the 163Ho-163Dy system for such an experiment.Comment: Some small changes in section 2, results unchanged. Added referenc
Observation of exotic meson production in the reaction at 18 GeV/c
An amplitude analysis of an exclusive sample of 5765 events from the reaction
at 18 GeV/c is described. The
production is dominated by natural parity exchange and by
three partial waves: those with and . A
mass-dependent analysis of the partial-wave amplitudes indicates the production
of the meson as well as the meson, observed for the
first time decaying to . The dominant, exotic
(non- partial wave is shown to be resonant with a mass of
GeV/c^2 and a width of GeV/c^2 . This exotic state, the , is produced with a
dependence which is different from that of the meson, indicating
differences between the production mechanisms for the two states.Comment: 5 pages with 4 figure
Neutral currents and tests of three-neutrino unitarity in long-baseline experiments
We examine a strategy for using neutral current measurements in long-baseline
neutrino oscillation experiments to put limits on the existence of more than
three light, active neutrinos. We determine the relative contributions of
statistics, cross section uncertainties, event misidentification and other
systematic errors to the overall uncertainty of these measurements. As specific
case studies, we make simulations of beams and detectors that are like the K2K,
T2K, and MINOS experiments. We find that the neutral current cross section
uncertainty and contamination of the neutral current signal by charge current
events allow a sensitivity for determining the presence of sterile neutinos at
the 0.10--0.15 level in probablility.Comment: 24 pages, Latex2e, uses graphicx.sty, 2 postscript figures. Submitted
to the Neutrino Focus Issue of New Journal Physics at http://www.njp.or
A partial wave analysis of the system produced in charge exchange collisions
A partial wave analysis of the of the system produced in the
charge exchange reaction: at an incident momentum of
is presented as a function of invariant mass,
, and momentum transfer squared, , from the incident
to the outgoing system.Comment: 24 pages total,8 pages text, 14 figures, 1 table. Submitted to Phys
Rev
Partial-wave analysis of the eta pi+ pi- system produced in the reaction pi-p --> eta pi+ pi- n at 18 GeV/c
A partial-wave analysis of 9082 eta pi+ pi- n events produced in the reaction
pi- p --> eta pi+ pi- n at 18.3 GeV/c has been carried out using data from
experiment 852 at Brookhaven National Laboratory. The data are dominated by
J^{PC} = 0^{-+} partial waves consistent with observation of the eta(1295) and
the eta(1440). The mass and width of the eta(1295) were determined to be 1282
+- 5 MeV and 66 +- 13 Mev respectively while the eta(1440) was observed with a
mass of 1404 +- 6 MeV and width of 80 +- 21 MeV. Other partial waves of
importance include the 1++ and the 1+- waves. Results of the partial wave
analysis are combined with results of other experiments to estimate f1(1285)
branching fractions. These values are considerably different from current
values determined without the aid of amplitude analyses.Comment: 22 pages, 8 figure
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