16,120 research outputs found
First observations of separated atmospheric nu(mu) and anti-nu(mu) events in the MINOS detector.
Multitype Contact Process on : Extinction and Interface
We consider a two-type contact process on in which both types have equal
finite range and supercritical infection rate. We show that a given type
becomes extinct with probability 1 if and only if, in the initial
configuration, it is confined to a finite interval and the other type
occupies infinitely many sites both in and . We
also show that, starting from the configuration in which all sites in
are occupied by type 1 particles and all sites in
are occupied by type 2 particles, the process defined by the size of
the interface area between the two types at time is tight
An analytic solution to the Busemann-Petty problem on sections of convex bodies
We derive a formula connecting the derivatives of parallel section functions
of an origin-symmetric star body in R^n with the Fourier transform of powers of
the radial function of the body. A parallel section function (or
(n-1)-dimensional X-ray) gives the ((n-1)-dimensional) volumes of all
hyperplane sections of the body orthogonal to a given direction. This formula
provides a new characterization of intersection bodies in R^n and leads to a
unified analytic solution to the Busemann-Petty problem: Suppose that K and L
are two origin-symmetric convex bodies in R^n such that the ((n-1)-dimensional)
volume of each central hyperplane section of K is smaller than the volume of
the corresponding section of L; is the (n-dimensional) volume of K smaller than
the volume of L? In conjunction with earlier established connections between
the Busemann-Petty problem, intersection bodies, and positive definite
distributions, our formula shows that the answer to the problem depends on the
behavior of the (n-2)-nd derivative of the parallel section functions. The
affirmative answer to the Busemann-Petty problem for n\le 4 and the negative
answer for n\ge 5 now follow from the fact that convexity controls the second
derivatives, but does not control the derivatives of higher orders.Comment: 13 pages, published versio
Monte Carlo Studies of the GCT Telescope for the Cherenkov Telescope Array
The GCT is an innovative dual-mirror solution proposed for the small-size
telescopes for CTA, capable of imaging primary cosmic gamma-rays from below a
TeV to hundreds of TeV. The reduced plate scale resulting from the secondary
optics allows the use of compact photosensors, including multi-anode
photomultiplier tubes or silicon photomultipliers. We show preliminary results
of Monte Carlo simulations using the packages CORSIKA and Sim_telarray,
comparing the relative performance of each photosensor type. We also
investigate the effect of the secondary optics in terms of optical performance,
image resolution and camera response. With the ongoing commissioning of the
prototype structure and camera, we present the preliminary expected performance
of GCT.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Divertor Heat Load in ASDEX Upgrade L-Mode in Presence of External Magnetic Perturbation
Power exhaust is one of the major challenges for a future fusion device.
Applying a non-axisymmetric external magnetic perturbation is one technique
that is studied in order to mitigate or suppress large edge localized modes
which accompany the high confinement regime in tokamaks. The external magnetic
perturbation brakes the axisymmetry of a tokamak and leads to a 2D heat flux
pattern on the divertor target. The 2D heat flux pattern at the outer divertor
target is studied on ASDEX Upgrade in stationary L-Mode discharges. The
amplitude of the 2D characteristic of the heat flux depends on the alignment
between the field lines at the edge and the vacuum response of the applied
magnetic perturbation spectrum. The 2D characteristic reduces with increasing
density. The increasing divertor broadening with increasing density is
proposed as the main actuator. This is supported by a generic model using field
line tracing and the vacuum field approach that is in quantitative agreement
with the measured heat flux. The perturbed heat flux, averaged over a full
toroidal rotation of the magnetic perturbation, is identical to the
non-perturbed heat flux without magnetic perturbation. The transport
qualifiers, power fall-off length and divertor broadening , are
the same within the uncertainty compared to the unperturbed reference. No
additional cross field transport is observed.Comment: 23 pages, 28 figures. This is an author-created, un-copyedited
version of an article submitted for publication in Plasma Physics and
Controlled Fusion. IoP Publishing Ltd is not responsible for any errors or
omissions in this version of the manuscript or any version derived from i
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