43,349 research outputs found
A primary electron beam facility at CERN
This document describes the concept of a primary electron beam facility at
CERN, to be used for dark gauge force and light dark matter searches. The
electron beam is produced in three stages: A Linac accelerates electrons from a
photo-cathode up to 3.5 GeV. This beam is injected into the Super Proton
Synchrotron, SPS, and accelerated up to a maximum energy of 16 GeV. Finally,
the accelerated beam is slowly extracted to an experiment, possibly followed by
a fast dump of the remaining electrons to another beamline. The beam parameters
are optimized using the requirements of the Light Dark Matter eXperiment, LDMX,
as benchmark
Diffeomorphism Invariant Integrable Field Theories and Hypersurface Motions in Riemannian Manifolds
We discuss hypersurface motions in Riemannian manifolds whose normal velocity
is a function of the induced hypersurface volume element and derive a second
order partial differential equation for the corresponding time function
at which the hypersurface passes the point . Equivalently, these
motions may be described in a Hamiltonian formulation as the singlet sector of
certain diffeomorphism invariant field theories. At least in some (infinite
class of) cases, which could be viewed as a large-volume limit of Euclidean
-branesmoving in an arbitrary -dimensional Riemannian manifold, the
models are integrable: In the time-function formulation the equation becomes
linear (with a harmonic function on the embedding Riemannian
manifold). We explicitly compute solutions to the large volume limit of
Euclidean membrane dynamics in \Real^3 by methods used in electrostatics and
point out an additional gradient flow structure in \Real^n. In the
Hamiltonian formulation we discover infinitely many hierarchies of integrable,
multidimensional, -component theories possessing infinitely many
diffeomorphism invariant, Poisson commuting, conserved charges.Comment: 15 pages, LATE
A primary electron beam facility at CERN
This paper describes the concept of a primary electron beam facility at CERN,
to be used for dark gauge force and light dark matter searches. The electron
beam is produced in three stages: A Linac accelerates electrons from a
photo-cathode up to 3.5 GeV. This beam is injected into the Super Proton
Synchrotron, SPS, and accelerated up to a maximum energy of 16 GeV. Finally,
the accelerated beam is slowly extracted to an experiment, possibly followed by
a fast dump of the remaining electrons to another beamline. The beam parameters
are optimized using the requirements of the Light Dark Matter eXperiment (LDMX)
as benchmark.Comment: 3 pages, 3 figure
Ecosystem Approach to Small Scale Tropical Marine Fisheries
This is a 4-page brochure about a WorldFish led project. Throughout the world, poor fisheries management contributes to resource degradation, poverty, and food insecurity. This European Union project on an Ecosystem Approach to Small-scale Tropical Marine Fisheries is led by WorldFish and implemented in collaboration with national partners in Asia (Southeastern)-Indonesia; the Asia (Southeastern)-Philippines; the Solomon Islands and Tanzania. The overall objective is to use an ecosystem approach to fisheries management (EAFM) to improve governance of small-scale fisheries (SSF). The EAFM puts sustainability and equitability at the forefront of fisheries governance which enhances their contribution to poverty reduction.Specific objectives are to: 1. Assess existing institutional arrangements and identify opportunities for an EAFM to improve integrated SSF management; 2. Develop EAFM strategies and actions suitable for developing country contexts; 3. Strengthen the capacity of local fishery stakeholders and government agencies to collaborate and work within an EAFM. The project is taking a participatory and gender sensitive approach, both core philosophies of WorldFish. Representatives of all relevant stakeholder groups are involved in this action research project
Topics in chaotic dynamics
Various kinematical quantities associated with the statistical properties of
dynamical systems are examined: statistics of the motion, dynamical bases and
Lyapunov exponents. Markov partitons for chaotic systems, without any attempt
at describing ``optimal results''. The Ruelle principle is illustrated via its
relation with the theory of gases. An example of an application predicts the
results of an experiment along the lines of Evans, Cohen, Morriss' work on
viscosity fluctuations. A sequence of mathematically oriented problems
discusses the details of the main abstract ergodic theorems guiding to a proof
of Oseledec's theorem for the Lyapunov exponents and products of random
matricesComment: Plain TeX; compile twice; 30 pages; 140K Keywords: chaos,
nonequilibrium ensembles, Markov partitions, Ruelle principle, Lyapunov
exponents, random matrices, gaussian thermostats, ergodic theory, billiards,
conductivity, gas.
Excess comovement in credit default swap markets: Evidence from the CDX indices
We provide evidence of excess comovement in the credit default swap (CDS) market following inclusions to and exclusions from investment grade and high yield CDX indices during the 2003–2016 period. We find that when a name joins an index, its return tends to covary more with the returns of that index and conversely when it is excluded from an index, its return tends to covary less with it. We use univariate regressions and a difference-in-difference approach to show that the CDS market is impacted by indexation. This excess comovement indicates a departure from fundamental-based pricing and provides support in favour of style investing
Depletion potential in hard-sphere mixtures: theory and applications
We present a versatile density functional approach (DFT) for calculating the
depletion potential in general fluid mixtures. In contrast to brute force DFT,
our approach requires only the equilibrium density profile of the small
particles {\em before} the big (test) particle is inserted. For a big particle
near a planar wall or a cylinder or another fixed big particle the relevant
density profiles are functions of a single variable, which avoids the numerical
complications inherent in brute force DFT. We implement our approach for
additive hard-sphere mixtures. By investigating the depletion potential for
high size asymmetries we assess the regime of validity of the well-known
Derjaguin approximation for hard-sphere mixtures and argue that this fails. We
provide an accurate parametrization of the depletion potential in hard-sphere
fluids which should be useful for effective Hamiltonian studies of phase
behavior and colloid structure
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