Teleological computer graphics modeling

Summary form only give. Teleological modeling, a developing approach for creating abstractions and mathematical representations of physically realistic time-dependent objects, is described. In this approach, geometric constraint-properties, mechanical properties of objects, the parameters representing an object, and the control of the object are incorporated into a single conceptual framework. A teleological model incorporates time-dependent goals of behavior of purpose as the primary abstraction and representation of what the object is. A teleological implementation takes a geometrically incomplete specification of the motion, position, and shape of an object, and produces a geometrically complete description of the object's shape and behavior as a function of time. Teleological modeling techniques may be suitable for consideration in computer vision algorithms by extending the current notions about how to make mathematical representations of objects. Teleological descriptions can produce compact representations for many of the physically derivable quantities controlling the shapes, combining-operations, and constraints which govern the formation and motion of objects

Superquadrics and Angle-Preserving Transformations

Over the past 20 years, a great deal of interest has developed in the use of computer graphics and numerical methods for three-dimensional design. Significant progress in geometric modeling is being made, predominantly for objects best represented by lists of edges, faces, and vertices. One long-term goal of this work is a unified mathematical formalism, to form the basis of an interactive and intuitive design environment in which designers can simulate three-dimensional scenes with shading and texture, produce usable design images, verify numerical machining-control commands, and set up finite-element meshwork for structural and dynamic analysis. A new collection of smooth parametric objects and a new set of three-dimensional parametric modifiers show potential for helping to achieve this goal. The superquadric primitives and angle-preserving transformations extend the traditional geometric primitives-quadric surfaces and parametric patches-used in existing design packages, producing a new spectrum of flexible forms. Their chief advantage is that they allow complex solids and surfaces to be constructed and altered easily from a few interactive parameters

A boost for the EW SUSY hunt: monojet-like search for compressed sleptons at LHC14 with 100 fb^-1

Current Large Hadron Collider (LHC) analyses are blind to compressed supersymmetry (SUSY) models with sleptons near the lightest super partner (LSP) in mass: $m_{\tilde{l}} - m_{\tilde{\chi}_1^0} \equiv \Delta m \lesssim 60$ GeV. We present a search sensitive to the very compressed range $3~\text{GeV} < \Delta m < 24~\text{GeV}$ using the channel $p p \rightarrow \tilde{l}^+ \tilde{l}^- +\rm{jet} \rightarrow$ $l^+ l^- \tilde{\chi}_1^0 \tilde{\chi}_1^0 +\rm{jet}$ with soft same-flavor leptons and one hard jet from initial state radiation ($p_{\rm T}^j >100$ GeV). The sleptons recoil against the jet boosting them and their decay products, making the leptons detectable and providing substantial missing transverse momentum. We use the kinematic variable $m_{\rm T 2}$ along with a different-flavor control region to reduce the large standard model backgrounds and control systematic uncertainty. We find the analysis should allow LHC14 with $100~\text{fb}^{-1}$ to search for degenerate left-handed selectrons and smuons in the compressed region up to $m_{\tilde{l}_L} \lesssim 150$ GeV. In addition, it should be sensitive to $m_{\tilde{l}_L} \lesssim 110$ GeV for the very challenging case of auto-concealed SUSY, in which left-handed sleptons decay to the Kaluza-Klein tower of a modulino LSP which lives in $d=6$ extra dimensions. In both the compressed spectrum and auto-concealed SUSY scenarios this analysis will need more data to improve on LEP2 limits for right-handed sleptons due to their smaller cross sections.Comment: 15 pages, 3 figures, updated citations in v

Oriented tensor reconstruction: tracing neural pathways from diffusion tensor MRI

In this paper we develop a new technique for tracing anatomical fibers from 3D tensor fields. The technique extracts salient tensor features using a local regularization technique that allows the algorithm to cross noisy regions and bridge gaps in the data. We applied the method to human brain DT-MRI data and recovered identifiable anatomical structures that correspond to the white matter brain-fiber pathways. The images in this paper are derived from a dataset having 121x88x60 resolution. We were able to recover fibers with less than the voxel size resolution by applying the regularization technique, i.e., using a priori assumptions about fiber smoothness. The regularization procedure is done through a moving least squares filter directly incorporated in the tracing algorithm

A Review of the Mass Measurement Techniques proposed for the Large Hadron Collider

We review the methods which have been proposed for measuring masses of new particles at the Large Hadron Collider paying particular attention to the kinematical techniques suitable for extracting mass information when invisible particles are expected.Comment: 72 pages - in form to be published in JPhys

Precision Determination of Invisible-Particle Masses at the CERN LHC: II

We further develop the constrained mass variable techniques to determine the mass scale of invisible particles pair-produced at hadron colliders. We introduce the constrained mass variable M_3C which provides an event-by-event lower bound and upper bound to the mass scale given the two mass differences between the lightest three new particle states. This variable is most appropriate for short symmetric cascade decays involving two-body decays and on-shell intermediate states which end in standard-model particles and two dark-matter particles. An important feature of the constrained mass variables is that they do not rely simply on the position of the end point but use the additional information contained in events which lie far from the end point. To demonstrate our method we study the supersymmetric model SPS 1a. We select cuts to study events with two Neutralino_2 each of which decays to Neutralino_1, and two opposite-sign same-flavor (OSSF) charged leptons through an intermediate on-shell slepton. We find that with 300 fb^-1 of integrated luminosity the invisible-particle mass can be measured to M=96.4 +/- 2.4 GeV. Combining fits to the shape of the M_3C constrained mass variable distribution with the max m_ll edge fixes the mass differences to +/- 0.2 GeV.Comment: 13 pages, 10 figure

Determining the spin of supersymmetric particles at the LHC using lepton charge asymmetry.

If signals suggesting supersymmetry (SUSY) are discovered at the LHC then it will be vital to measure the spins of the new particles to demonstrate that they are indeed the predicted super-partners. A method is discussed by which the spins of some of the SUSY particles can be determined. Angular distributions in sparticle decays lead to charge asymmetry in lepton-jet invariant mass distributions. The size of the asymmetry is proportional to the primary production asymmetry between squarks and anti-squarks. Monte Carlo simulations are performed for a particular mSUGRA model point at the LHC. The resultant asymmetry distributions are consistent with a spin-0 slepton and a spin- 1 2 ˜ 0 2, but are not consistent with both particles being scalars

Faster Calculation of Superquadric Shapes

Nonparametric methods of calculating points on the curve produce the recently introduced superquadric objects at great savings in time

Testing Bell inequalities in Higgs boson decays

Higgs boson decays produce pairs of $W$ bosons in a maximally entangled state, the spins of which can be expected to violate Bell inequalities. We show that the spin density matrix of the $W^\pm$ pair may be reconstructed experimentally from the directions of the charged lepton decay products, and from it the expectation values of various Bell operators determined. Numerical simulations of $H\rightarrow WW^*$ decays indicate that violation of the CHSH inequality is unlikely to be measurable, however the CGLMP inequality is near-maximally violated. Experimental Bell tests could be performed at a variety of colliders and in different production channels. If reconstruction effects and backgrounds can be controlled then statistically significant violations could be observable even with datasets comparable to those already collected at the LHC7Comment: 7 pages, 2 tables. Additional discussion on the generality of the method, and additional table showing further experimental scenario