8,629 research outputs found
Heavy Z': resonant versus non-resonant searches
Collider searches for new vector-like particles such as Z' have mostly been
pursued by looking for a peak in the invariant mass spectrum of the decay
products. However off-shell Z' exchange may leave an imprint on other kinematic
distributions, leading thus to non-resonant searches. The aim of this paper is
to assess, in the context of the LHC, the interplay between resonant
(s-channel) and non-resonant (t-channel) searches for a generic leptophobic Z'
model. We show in particular that while non-resonant searches are less
sensitive to small couplings, they tend to be more adapted at high masses and
large couplings. We discuss our findings both at the level of the current
limits and the expectations at higher luminosities
Twisted Superspace
We formulate the ten-dimensional super-Yang-Mills theory in a twisted
superspace with 8+1 supercharges. Its constraints do not imply the equations of
motion and we solve them. As a preliminary step for a complete formulation in a
twisted superspace, we give a superspace path-integral formulation of the N=2,
d=4 super-Yang-Mills theory without matter. The action is the sum of a
Chern--Simons term depending on a super-connection plus a BF-like term. The
integration over the superfield B implements the twisted superspace constraints
on the super-gauge field, and the Chern-Simons action reduces to the known
action in components
Improved Modal Assurance Criterion using a quantification of identification errors per mode/sensor
Scanning laser vibrometer measurements generate detailed maps of modal characteristics in normal or 3D directions. Since many points are measured, individual validation of cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy. The key new notion of the paper is a quantification of identification error and level of contribution for each mode and each sensor based on the comparison of measured and synthesized transfers around each resonance. These criteria are shown to allow efficient analysis of the validity of large measurement sets to provide an automated procedure to select sensors that should be kept for each mode. This quantification, being performed before correlation, provides a priori estimates of sources of poor correlation associated with the identification process. It thus becomes possible to provide improved Modal Assurance Criterion estimations where, for each modeshape, sensors known to be incorrectly identified can be discarded. The 3D vibrometer scan of a brake component is used to illustrate the proposed strategies
A comparative evaluation of two algorithms of detection of masses on mammograms
In this paper, we implement and carry out the comparison of two methods of
computer-aided-detection of masses on mammograms. The two algorithms basically
consist of 3 steps each: segmentation, binarization and noise suppression using
different techniques for each step. A database of 60 images was used to compare
the performance of the two algorithms in terms of general detection efficiency,
conservation of size and shape of detected masses.Comment: 9 pages, 5 figures, 1 table, Vol.3, No.1, February 2012,pp19-27;
Signal & Image Processing : An International Journal (SIPIJ),201
Directional Dynamics along Arbitrary Curves in Cellular Automata
This paper studies directional dynamics in cellular automata, a formalism
previously introduced by the third author. The central idea is to study the
dynamical behaviour of a cellular automaton through the conjoint action of its
global rule (temporal action) and the shift map (spacial action): qualitative
behaviours inherited from topological dynamics (equicontinuity, sensitivity,
expansivity) are thus considered along arbitrary curves in space-time. The main
contributions of the paper concern equicontinuous dynamics which can be
connected to the notion of consequences of a word. We show that there is a
cellular automaton with an equicontinuous dynamics along a parabola, but which
is sensitive along any linear direction. We also show that real numbers that
occur as the slope of a limit linear direction with equicontinuous dynamics in
some cellular automaton are exactly the computably enumerable numbers
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