3,904 research outputs found
The Search for Neutrino Oscillations numubar->nuebar with KARMEN
The neutrino experiment KARMEN is situated at the beam stop neutrino source
ISIS. It provides numu's, nue's and numubar's in equal intensities from the pi+
mu+ decay at rest (DAR). The oscillation channel numub->nueb is investigated in
the appearance mode with a 56t liquid scintillation calorimeter at a mean
distance of 17.7m from the nu source looking for p(nue,e+)n reactions. The
cosmic induced background for this oscillation search could be reduced by a
factor of 40 due to an additional veto counter installed in 1996. In the data
collected through 1997 and 1998 no potential oscillation event was observed.
Using a unified approach to small signals this leads to an upper limit for the
mixing angle of sin**2(2t) < 1.3x10^{-3} (90%CL) at large Dm**2. The excluded
area in (sin**2(2t),Dm**2) covers almost entirely the favored region defined by
the LSND numub->nueb evidence.Comment: Proceedings Contribution to Neutrino98 in Takayama, Japan, June 4-9,
1998; 13 pages, including 4 figure
Detection of Accelerator-Produced Neutrinos at a Distance of 250 km
The KEK to Kamioka long-baseline neutrino experiment (K2K) has begun its
investigation of neutrino oscillations suggested by atmospheric neutrino
observations. Twenty-eight neutrino events have been detected in coincidence
with the expected arrival time of the beam in the 22.5 kt fiducial volume of
Super--Kamiokande, the far detector at 250 km distance. The expectation is
37.8+3.5-3.8, derived using measurements of neutrino interactions in a near
detector and extrapolation using a beam simulation validated by a measurement
of pion kinematics after production and focusing. The background is of order
10^-3 events.Comment: 6 pages, 3 embedded figures, LaTeX with RevTeX style, submitted to
PRL. This version is As Submitte
Nuclear Many-Body Theory of Electroweak Interactions with Nuclei at Intermediate Energies
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron model
developed in reference \cite{GNO97} is extended to the study of electroweak
Charged Current (CC) induced nuclear reactions at intermediate energies of
interest for future neutrino oscillation experiments. Long range nuclear (RPA)
correlations, Final State Interaction (FSI) and Coulomb corrections are
included within the model. RPA correlations are shown to play a crucial role in
the whole range of neutrino energies, up to 500 MeV, studied in this work.
Predictions for inclusive muon capture for different nuclei through the
Periodic Table and for the reactions C and C
near threshold are also given.Comment: Talk given by J. Nieves at NUINT04, Gran Sasso, March 200
The Effects of Deformation on Isovector Electromagnetic and Weak Transition Strengths
The summed strength for transitions from the ground state of via the
operators and
are calculated using the rotational
model. If we choose the z component of the isospin operator , the above
operators are relevant to electromagnetic transitions; if we choose
they are relevant to weak transitions such as neutrino capture. In going from
the spherical limit to the asymptotic (oblate) limit the strength for the
operator decreases steadily to zero; the strength for the operator
(scissors mode) increases by a factor of three. For the last
three operators - isovector dipole, spin dipole and orbital dipole (including
the twist mode) it is shown that the summed strength is independant of
deformation. The main difference in the behavior is that for the first two
operators we have in-shell transitions whereas for the last three operators the
transitions are out of shell.Comment: 14 pages, late
Pulse shape analysis in segmented detectors as a technique for background reduction in Ge double-beta decay experiments
The need to understand and reject backgrounds in Ge-diode detector
double-beta decay experiments has given rise to the development of pulse shape
analysis in such detectors to discern single-site energy deposits from
multiple-site deposits. Here, we extend this analysis to segmented Ge detectors
to study the effectiveness of combining segmentation with pulse shape analysis
to identify the multiplicity of the energy deposits.Comment: 12 pages, 13 figures, will be submitted to NI
The D0 Run IIb Luminosity Measurement
An assessment of the recorded integrated luminosity is presented for data
collected with the D0 detector at the Fermilab Tevatron Collider from June 2006
to September 2011 (Run IIb). In addition, a measurement of the effective cross
section for inelastic interactions, also referred to as the luminosity
constant, is reported. This measurement incorporates new features that lead to
a substantial improvement in the precision of the result. A luminosity constant
of \sigma_{LM} = 48.3\pm1.9\pm0.6 mb is obtained, where the first uncertainty
is due to the accuracy of the inelastic cross section used by both CDF and D0,
and the second uncertainty is due to D0 sources. The recorded luminosity for
the highest E_T jet trigger is L_rec = 9.2 \pm 0.4 fb^{-1}, with a relative
uncertainty of 4.3%.Comment: 20 pages, 23 figure
The Control System for a new Pixel Detector at the sLHC
For the upgrade of the LHC, the sLHC (super Large Hadron Collider), a new ATLAS Pixel Detector is planned, which will require a completely new control system. To reduce the material budget new power distribution schemes are under investigation, where the active power conversion is located inside the detector volume. Such a new power supply system will need new control strategies. Parts of the control must be located closer to the loads. The minimization of mass, the demand for less cables and the re-use of the outer existing services are the main restrictions to the design of the control system. The requirements of the DCS (Detector Control System) and a first concept will be presented. We will focus on a control chip which necessarily has to be implemented in the new system. A setup of discrete components has been built up to investigate and verify the chip’s requirements. We report on the status of the work
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