173 research outputs found
Measurement of , Structure Functions and Gross--Llewellyn Smith Sum Rule with IHEP--JINR Neutrino Detector
The isoscalar structure functions xF_3 and F_2 are measured as functions of x
averaged over all Q^2 permissible for the range 6 to 28 GeV of incident
(anti)neutrino energy. With the measured values of xF_3, the value of the
Gross-Llewellyn Smith sum rule is found to be . The QCD analysis of xF_3 provides
. The obtained value of the strong
interaction constant is larger than most of
the deep inelastic scattering results.Comment: LaTeX, 10 pages, 1 figure can be obtained by FA
The leptonic CP phase from muon decay at rest with two detectors
We propose a novel experimental setup for the determination of the leptonic CP-violating phase δ using the decay at rest (DAR) of μ + from a single source located at distances of 10 and 30 km from two 20 kton organic liquid scintillator detectors. The μ + are created by bombarding a target with a 9 mA beam of 800 MeV protons. With this proposal δ can be determined with a precision of 20 (15) degrees in 6 (12) years. In contrast with the DAE δ ALUS project, only a single source is required and it runs with a duty factor limited only by maintenance requirements. As a result 9 mA is the maximum instantaneous current, greatly reducing both the technological challenges and the costs
Showering cosmogenic muons in a large liquid scintillator
We present the results of FLUKA simulations of the propagation of cosmogenic muons in a 20 kton spherical liquid scintillator detector underneath 700 to 900 meters of rock. A showering muon is one which deposits at least 3 GeV in the detector in addition to ionization energy. We find that 20 percent of muons are showering and a further 11 percent of muon events are muon bundles, of which more than one muon enters the detector. In this range the showering and bundle fractions are robust against changes in the depth and topography, thus the total shower and bundle rate for a given experiment can be obtained by combining our results with an estimate for the total muon flux. One consequence is that a straightforward adaptation of the full detector showering muon cuts used by KamLAND to JUNO or RENO 50 would yield a nearly vanishing detector efficiency
Medium baseline reactor neutrino experiments with two identical detectors
In the next 10 years medium baseline reactor neutrino experiments will attempt to determine the neutrino mass hierarchy and to precisely measure θ12 . Both of these determinations will be more reliable if data from identical detectors at distinct baselines are combined. While interference effects can be eliminated by choosing detector sites orthogonal to the reactor arrays, one of the greatest challenges facing a determination of the mass hierarchy is the detector's unknown energy response. By comparing peaks at similar energies at two identical detectors at distinct baselines, one eliminates any correlated dependence upon a monotonic energy response. In addition, a second detector leads to new hierarchy-dependent observables, such as the ratio of the locations of the maxima of the Fourier cosine transforms. A second detector at a distinct baseline also breaks the degeneracy between θ12 and the background neutrino flux from, for example, distant reactors and increases the effective target mass, which is limited by current designs to about 20 kton/detector
Dark Matter investigation by DAMA at Gran Sasso
Experimental observations and theoretical arguments at Galaxy and larger
scales have suggested that a large fraction of the Universe is composed by Dark
Matter particles. This has motivated the DAMA experimental efforts to
investigate the presence of such particles in the galactic halo by exploiting a
model independent signature and very highly radiopure set-ups deep underground.
Few introductory arguments are summarized before presenting a review of the
present model independent positive results obtained by the DAMA/NaI and
DAMA/LIBRA set-ups at the Gran Sasso National Laboratory of the INFN.
Implications and model dependent comparisons with other different kinds of
results will be shortly addressed. Some arguments put forward in literature
will be confuted
Results from an Algebraic Classification of Calabi-Yau Manifolds
We present results from an inductive algebraic approach to the systematic
construction and classification of the `lowest-level' CY3 spaces defined as
zeroes of polynomial loci associated with reflexive polyhedra, derived from
suitable vectors in complex projective spaces. These CY3 spaces may be sorted
into `chains' obtained by combining lower-dimensional projective vectors
classified previously. We analyze all the 4242 (259, 6, 1) two- (three-, four-,
five-) vector chains, which have, respectively, K3 (elliptic, line-segment,
trivial) sections, yielding 174767 (an additional 6189, 1582, 199) distinct
projective vectors that define reflexive polyhedra and thereby CY3 spaces, for
a total of 182737. These CY3 spaces span 10827 (a total of 10882) distinct
pairs of Hodge numbers h_11, h_12. Among these, we list explicitly a total of
212 projective vectors defining three-generation CY3 spaces with K3 sections,
whose characteristics we provide
Status Report of the Inter-Laboratory Task Force on Remote Operation
In February 2000, the International Committee for Future Accelerators
initiated a study of a new model for international collaboration on a future
large accelerator project, the Global Accelerator Network. The study is based
on a model of a facility, which is remote from most of the collaborating
institutions. It is designed, built and operated by a collaboration of equal
partner institutions distributed around the world. According to this model, the
expert-staff from each laboratory remains based at their home institution but
continues to participate in the operation of the machine after construction.
This report summarizes the conclusions of the Task Force on Remote Operation,
which investigated the general and technical implications of far-remote
operations
Channeling and Volume Reflection Based Crystal Collimation of Tevatron Circulating Beam Halo (T-980)
The T980 crystal collimation experiment is underway at the Tevatron to
determine if this technique could increase 980 GeV beam-halo collimation
efficiency at high-energy hadron colliders such as the Tevatron and the LHC.
T980 also studies various crystal types and parameters. The setup has been
substantially enhanced during the Summer 2009 shutdown by installing a new
O-shaped crystal in the horizontal goniometer, as well as adding a vertical
goniometer with two alternating crystals (O-shaped and multi-strip) and
additional beam diagnostics. First measurements with the new system are quite
encouraging, with channeled and volume-reflected beams observed on the
secondary collimators as predicted. Investigation of crystal collimation
efficiencies with crystals in volume reflection and channeling modes are
described in comparison with an amorphous primary collimator. Results on the
system performance are presented for the end-of-store studies and for entire
collider stores. The first investigation of colliding beam collimation
simultaneously using crystals in both the vertical and horizontal plane has
been made in the regime with horizontally channeled and vertically
volume-reflected beams. Planning is underway for significant hardware
improvements during the FY10 summer shutdown and for dedicated studies during
the final year of Tevatron operation and also for a "post-collider beam physics
running" period
How to Commission, Operate and Maintain a Large Future Accelerator Complex From Far Remote Sites
A study on future large accelerators [1] has considered a facility, which is
designed, built and operated by a worldwide collaboration of equal partner
institutions, and which is remote from most of these institutions. The full
range of operation was considered including commissioning, machine development,
maintenance, troubleshooting and repair. Experience from existing accelerators
confirms that most of these activities are already performed 'remotely'. The
large high-energy physics experiments and astronomy projects, already involve
international collaborations of distant institutions. Based on this experience,
the prospects for a machine operated remotely from far sites are encouraging.
Experts from each laboratory would remain at their home institution but
continue to participate in the operation of the machine after construction.
Experts are required to be on site only during initial commissioning and for
particularly difficult problems. Repairs require an on-site non-expert
maintenance crew. Most of the interventions can be made without an expert and
many of the rest resolved with remote assistance. There appears to be no
technical obstacle to controlling an accelerator from a distance. The major
challenge is to solve the complex management and communication problems
How to Commission, Operate and Maintain a Large Future Accelerator Complex from Far Remote
A study on future large accelerators [1] has considered a facility, which is
designed, built and operated by a worldwide collaboration of equal partner
institutions, and which is remote from most of these institutions. The full
range of operation was considered including commi-ssioning, machine
development, maintenance, trouble shooting and repair. Experience from existing
accele-rators confirms that most of these activities are already performed
'remotely'. The large high-energy physics ex-periments and astronomy projects,
already involve inter-national collaborations of distant institutions. Based on
this experience, the prospects for a machine operated remotely from far sites
are encouraging. Experts from each laboratory would remain at their home
institution but continue to participate in the operation of the machine after
construction. Experts are required to be on site only during initial
commissioning and for par-ticularly difficult problems. Repairs require an
on-site non-expert maintenance crew. Most of the interventions can be made
without an expert and many of the rest resolved with remote assistance. There
appears to be no technical obstacle to controlling an accelerator from a
distance. The major challenge is to solve the complex management and
communication problems
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