2,648 research outputs found
Masses, Lifetimes and Decays of B Hadrons at the Tevatron
The latest results in B physics from the CDF and D0 experiments at the
Tevatron are presented, including inclusive b lifetime measurement and
exclusive lifetime measurement of the B_s. Promising samples collected by CDF
with its Secondary Vertex Trigger are shown as well.Comment: Proceedings 38th Rencontres de Moriond on QCD and High-Energy
Hadronic Interactions, Les Arcs, Savoie, France, March 22-29, 200
Search for Extra Dimensions at LHC
Some of the studies performed by the ATLAS and CMS collaborations to
establish the future sensitivity of the experiments to extra dimension signals
are reviewed. The discrimination of those signals from other new physics
signals and the extraction of the underlying parameters of the extra dimension
models are discussed.Comment: Proceedings of the International Europhysics Conference on High
Energy Physics EPS 2003 (July 17-23, 2003), Aachen, German
Model Independent Extra-dimension signatures with ATLAS
The generic missing transverse energy signals at LHC for theories having
large extra dimensions are discussed. Final states of jets plus missing energy
and photons plus missing energy are simulated in the ATLAS detector. The
discovery limit of LHC and the methods to determine the parameters of the
underlying model are discussed.Comment: 29 page
Prospects for b-tagging in ATLAS and tracking commissioning results with cosmic rays
The ability to identify jets containing B hadrons is important for the high-pT physics program of a general-purpose experiment at the LHC such as ATLAS. This capability relies on the very accurate measurements of the parameters of charged tracks provided by the ATLAS Inner Detector. Using millions of cosmic-ray tracks collected during the automn 2008, the ATLAS Inner Detector has been aligned and its tracking performance assessed. Some of the very encouraging results which have been obtained and are relevant for b-tagging are discussed, notably the current level of alignment of the detector and the resolution on the transverse impact parameter of tracks. The various b-tagging algorithms are then described, and their anticipated performance discussed in the light of the cosmic-ray data results. Finaly,the expected accuracy with which the b-tagging performance will be measured in data is mentioned
Spectra of Field Fluctuations in Braneworld Models with Broken Bulk Lorentz Invariance
We investigate five-dimensional braneworld setups with broken Lorentz
invariance continuing the developments of our previous paper (arXiv:0712.1136),
where a family of static self-tuning braneworld solutions was found. We show
that several known braneworld models can be embedded into this family. Then we
give a qualitative analysis of spectra of field fluctuations in backgrounds
with broken Lorentz invariance. We also elaborate on one particular model and
study spectra of scalar and spinor fields in it. It turns out that the spectra
we have found possess very peculiar and unexpected properties.Comment: 30 pages, 8 figures, minor corrections, references added, note adde
Signals of Models with Large Extra Dimensions in ATLAS
The generic missing transverse energy signals at LHC for theories having large extra dimensions are discussed. Final states of jets plus missing energy and photons plus missing energy are simulated in the ATLAS detector. The discovery limit of LHC and the methods to determine the parameters of the underlying model are discussed
Dynamic Reconstruction of Complex Planar Objects on Irregular Isothetic Grids
International audienceThe vectorization of discrete regular images has been widely developed in many image processing and synthesis applications, where images are considered as a regular static data. Regardless of final application, we have proposed in [14] a reconstruction algorithm of planar graphical elements on irregular isothetic grids. In this paper, we present a dynamic version of this algorithm to control the reconstruction. Indeed, we handle local refinements to update efficiently our complete shape representation. We also illustrate an application of our contribution for interactive approximation of implicit curves by lines, controlling the topology of the reconstruction
Unsupervised Polygonal Reconstruction of Noisy Contours by a Discrete Irregular Approach
International audienceIn this paper, we present an original algorithm to build a polygonal reconstruction of noisy digital contours. For this purpose, we first improve an algorithm devoted to the vectorization of discrete irregular isothetic objects. Afterwards we propose to use it to define a reconstruction process of noisy digital contours. More precisely, we use a local noise detector, introduced by Kerautret and Lachaud in IWCIA 2009, that builds a multi-scale representation of the digital contour, which is composed of pixels of various size depending of the local amount of noise. Finally, we compare our approach with previous works, by con- sidering the Hausdorff distance and the error on tangent orientations of the computed line segments to the original perfect contour. Thanks to both synthetic and real noisy objects, we show that our approach has interesting performance, and could be applied in document analysis systems
Search for the radion using the ATLAS detector
The possibility of observing the radion using the ATLAS detector at LHC is investigated. Studies on searches for the Standard Model Higgs with the ATLAS detector are re-interpreted to obtain limits on radion decay to gamma-gamma and ZZ(*). The observability of radion decays into Higgs pairs, which subsequently decay into gamma-gamma+b-bbar or tau-tau+b-bbar is then estimate
Curvature-Scale-based Contour Understanding for Leaf Margin Shape Recognition and Species Identification
International audienceIn the frame of a tree species identifying mobile application, designed for a wide scope of users, and with didactic purposes, we developed a method based on the computation of explicit leaf shape descriptors inspired by the criteria used in botany. This paper focuses on the characterization of the leaf contour, the extraction of its properties, and its description using botanical terms. Contour properties are investigated using the Curvature-Scale Space representation, the potential teeth explicitly extracted and described, and the margin classified into a set of inferred shape classes. Results are presented for both margin shape characterization, and leaf classification over nearly 80 tree species
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