75,317 research outputs found
Associated scalar-vector production at the LHC within an effective Lagrangian approach
We consider the case in which a strong dynamics is responsible for
Electro-Weak Symmetry Breaking (EWSB) and both a scalar and a vector ,
respectively a singlet and a triplet under a custodial , are
relevant and have a mass below the cut-off . In this
framework we study the total cross sections for the associated production
at the LHC at 14 TeV as functions of two independent free parameters.Comment: To appear in the Proceedings of IFAE2010 - Incontri di Fisica delle
Alte Energie, Rome, Italy, 7-9 April 201
Geology and wines of Pachino - Portopalo area : preliminary outlines
This research, still in a developmental
phase, analyses geological peculiarities and the relation-
ships between them and the vineyards typical to the
Pachino-Portopalo area.
The actual knowledge does not yet allow the drawing of tourist routes from which a geo-tourist would be
able to join together Geosites and Oenosites. This will
be one of the main topics of future research, oriented
to produce substantial contributions to the sustainable
development of this area.peer-reviewe
Channel-based key generation for encrypted body-worn wireless sensor networks
Body-worn sensor networks are important for rescue-workers, medical and many other applications. Sensitive data are often transmitted over such a network, motivating the need for encryption. Body-worn sensor networks are deployed in conditions where the wireless communication channel varies dramatically due to fading and shadowing, which is considered a disadvantage for communication. Interestingly, these channel variations can be employed to extract a common encryption key at both sides of the link. Legitimate users share a unique physical channel and the variations thereof provide data series on both sides of the link, with highly correlated values. An eavesdropper, however, does not share this physical channel and cannot extract the same information when intercepting the signals. This paper documents a practical wearable communication system implementing channel-based key generation, including an implementation and a measurement campaign comprising indoor as well as outdoor measurements. The results provide insight into the performance of channel-based key generation in realistic practical conditions. Employing a process known as key reconciliation, error free keys are generated in all tested scenarios. The key-generation system is computationally simple and therefore compatible with the low-power micro controllers and low-data rate transmissions commonly used in wireless sensor networks
A Deformation Theory of Self-Dual Einstein Spaces
The self-dual Einstein equations on a compact Riemannian 4-manifold can be
expressed as a quadratic condition on the curvature of an (spin)
connection which is a covariant generalization of the self-dual Yang-Mills
equations. Local properties of the moduli space of self-dual Einstein
connections are described in the context of an elliptic complex which arises in
the linearization of the quadratic equations on the curvature. In
particular, it is shown that the moduli space is discrete when the cosmological
constant is positive; when the cosmological constant is negative the moduli
space can be a manifold the dimension of which is controlled by the
Atiyah-Singer index theorem.Comment: 13 page
Covariant Phase Space Formulation of Parametrized Field Theories
Parametrized field theories, which are generally covariant versions of
ordinary field theories, are studied from the point of view of the covariant
phase space: the space of solutions of the field equations equipped with a
canonical (pre)symplectic structure. Motivated by issues arising in general
relativity, we focus on: phase space representations of the spacetime
diffeomorphism group, construction of observables, and the relationship between
the canonical and covariant phase spaces.Comment: 22 page
Natural Symmetries of the Yang-Mills Equations
We define a natural generalized symmetry of the Yang-Mills equations as an
infinitesimal transformation of the Yang-Mills field, built in a local, gauge
invariant, and Poincar\'e invariant fashion from the Yang-Mills field strength
and its derivatives to any order, which maps solutions of the field equations
to other solutions. On the jet bundle of Yang-Mills connections we introduce a
spinorial coordinate system that is adapted to the solution subspace defined by
the Yang-Mills equations. In terms of this coordinate system the complete
classification of natural symmetries is carried out in a straightforward
manner. We find that all natural symmetries of the Yang-Mills equations stem
from the gauge transformations admitted by the equations.Comment: 23 pages, plain Te
Schrodinger representation for the polarized Gowdy model
The polarized Gowdy model is, in a standard gauge, characterized
by a point particle degree of freedom and a scalar field degree of freedom
obeying a linear field equation on . The Fock
representation of the scalar field has been well-studied. Here we construct the
Schrodinger representation for the scalar field at a fixed value of the Gowdy
time in terms of square-integrable functions on a space of distributional
fields with a Gaussian probability measure. We show that ``typical'' field
configurations are slightly more singular than square-integrable functions on
the circle. For each time the corresponding Schrodinger representation is
unitarily equivalent to the Fock representation, and hence all the Schrodinger
representations are equivalent. However, the failure of unitary
implementability of time evolution in this model manifests itself in the mutual
singularity of the Gaussian measures at different times.Comment: 13 page
- âŠ