Results for "Michael D. Albrow"
total 160413took 0.28s
Early Estimation of Microlensing Event MagnificationsFeb 13 2004Gravitational microlensing events with high peak magnifications provide a much enhanced sensitivity to the detection of planets around the lens star. However, estimates of peak magnification during the early stages of an event by means of chi^2 minimization ... More Precision proton spectrometers for CMSOct 16 2013Oct 30 2013We plan to add high precision tracking- and timing-detectors at z = +/- 240 m to CMS to study exclusive processes p + p -- p + X + p at high luminosity. This enables the LHC to be used as a tagged photon-photon collider, with X = l+l- and W+W-, and as ... More Double Pomeron Exchange: from the ISR to the LHCOct 04 2010I discuss Double Pomeron Exchange processes from their first observation at the CERN Intersecting Storage Rings, focusing on glueball searches, through the observations of exclusive chi_c, photon-photon, and di-jets at the Tevatron, to prospects at the ... More Exclusive High Mass Di-leptons in CDFSep 18 2009In the Collider Detector at Fermilab, CDF, we have measured central exclusive production, p+pbar --> p+X+pbar, where X is a pair of leptons or photons and nothing else. In this talk I focus on central masses M(X) > 8 GeV/c2. We measured QED production ... More The White Pomeron, Color Sextet Quarks and Cosmic Ray AnomaliesSep 27 2004I introduce the critical pomeron theory ("white pomeron") proposed by Alan White, with its prediction of excessive WW and ZZ production at the LHC especially by double pomeron exchange (DPE), which is a crucial test. This theory implies dramatic effects ... More Diffractive Structure Functions at the TevatronFeb 08 2001We have studied events with a high-x_F antiproton and two central jets with E_T>7 GeV in CDF, in p+p_bar collisions at sqrt(s) = 1800 GeV. From the di-jet kinematics we derive the diffractive structure function of the antiproton. We also find an excess ... More Central exclusive production at the TevatronDec 02 2008In CDF we have observed several exclusive processes: 2-photon --> e+e- and --> mu+mu-, photon+pomeron --> J/psi and psi(2S), and pomeron+pomeron --> chi_c. The cross sections agree with QED, HERA photoproduction data, and theoretical estimates of gg --> ... More QCD and Hard Diffraction at the LHCSep 26 2005As an introduction to QCD at the LHC I give an overview of QCD at the Tevatron, emphasizing the high Q^2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular central exclusive ... More Central exclusive production at the TevatronSep 01 2014The Collider Detector at Fermilab, CDF, observed for the first time in hadron-hadron collisions photon-photon to e+e- and mu+mu-, photon-pomeron to J/psi and psi(2S), and pomeron-pomeron to photon+photon and to chi_c. Exclusive pi+pi- production by double ... More Double Pomeron Physics at the LHCJul 25 2005I discuss central exclusive production, otherwise known as Double Pomeron Exchange, DPE, from the ISR through the Tevatron to the LHC. There I emphasize the interest of exclusive Higgs and WW/ZZ production. The Frequency of Binary Stars in the Core of 47 TucanaeMay 24 2001Differential time series photometry has been derived for 46422 main-sequence stars in the core of 47 Tucanae. The observations consisted of near-continuous 160-s exposures alternating between the F555W and F814W filters for 8.3 days in 1999 July with ... More Exclusive Central pi+pi- production in CDFOct 14 2013Using the Collider Detector at Fermilab, CDF, we have measured exclusive pi+pi- production at sqrt(s) = 900 GeV and 1960 GeV. The pi+pi- pair is central, |y| < 1.0, and there are no other particles detected in |eta| < 5.9. We discuss the mass spectrum, ... More Forward Physics with Rapidity Gaps at the LHCNov 02 2008Aug 03 2009A rapidity gap program with great potential can be realized at the Large Hadron Collider, LHC, by adding a few simple forward shower counters (FSCs) along the beam line on both sides of the main central detectors, such as CMS. Measurements of single diffractive ... More KMT-2016-BLG-1107: A New Hollywood-Planet Close/Wide DegeneracyMay 22 2018Nov 13 2018We show that microlensing event KMT-2016-BLG-1107 displays a new type of degeneracy between wide-binary and close-binary Hollywood events in which a giant-star source envelops the planetary caustic. The planetary anomaly takes the form of a smooth, two-day ... More Accelerator Data for Cosmic Ray PhysicsSep 21 2010I present selected examples of accelerator data, mainly from hadron colliders, that are relevant for understanding cosmic ray showers. I focus on the forward region, $x_{Feynman} > 0.05$, where high energy data are scarce, since the emphasis in collider ... More Physics at Future Hadron CollidersJan 23 2002We discuss the physics opportunities and detector challenges at future hadron colliders. As guidelines for energies and luminosities we use the proposed luminosity and/or energy upgrade of the LHC (SLHC), and the Fermilab design of a Very Large Hadron ... More KELT-22Ab: A Massive Hot Jupiter Transiting a Near Solar TwinMar 20 2018We present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright ($V\sim 11.1$) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of $P = 1.3866529 \pm 0.0000027 $ days, a radius ... More Lorentz violation and topological defectsMar 13 2014If Lorentz symmetry is broken, it must have occurred dynamically, via a vector or tensor field whose potential energy forces it to take on a non-zero background expectation value "in vacuum". If the set of minima of this potential (the vacuum manifold) ... More Embedding Graphs into the Extended GridFeb 28 2007Let $G=(V,E)$ be an arbitrary undirected source graph to be embedded in a target graph $EM$, the extended grid with vertices on integer grid points and edges to nearest and next-nearest neighbours. We present an algorithm showing how to embed $G$ into ... More A Statistical Approach to Crime LinkageOct 08 2014The object of this paper is to develop a statistical approach to criminal linkage analysis that discovers and groups crime events that share a common offender and prioritizes suspects for further investigation. Bayes factors are used to describe the strength ... More Hereditary unigraphs and Erdős--Gallai equalitiesFeb 12 2013We give characterizations of the structure and degree sequences of hereditary unigraphs, those graphs for which every induced subgraph is the unique realization of its degree sequence. The class of hereditary unigraphs properly contains the threshold ... More OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian SiblingMay 15 2019We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio $q=M_{\rm planet}/M_{\rm host}\simeq 1\times10^{-4}$. Although there are no obvious systematic ... More A survey of spinning test particle orbits in Kerr spacetimeFeb 25 2003We investigate the dynamics of the Papapetrou equations in Kerr spacetime. These equations provide a model for the motion of a relativistic spinning test particle orbiting a rotating (Kerr) black hole. We perform a thorough parameter space search for ... More Dynamics of spinning test particles in Kerr spacetimeOct 14 2002Feb 12 2003We investigate the dynamics of relativistic spinning test particles in the spacetime of a rotating black hole using the Papapetrou equations. We use the method of Lyapunov exponents to determine whether the orbits exhibit sensitive dependence on initial ... More How Uniform is the Uniform Distribution on Permutations?Jan 10 2019For large $q$, does the (discrete) uniform distribution on the set of $q!$ permutations of the vector $(1,2,\dots,q)$ closely approximate the (continuous) uniform distribution on the $(q-2)$-sphere that contains them? These permutations comprise the vertices ... More The derivative expansion of the exact renormalization groupAug 06 2001We formulate a method of performing non-perturbative calculations in quantum field theory, based upon a derivative expansion of the exact renormalization group. We then proceed to apply this method to the calculation of critical exponents for three dimensional ... More Etale Homotopy Types and Bisimplicial HypercoversFeb 18 2010Feb 04 2011An \'etale homotopy type $T(X, z)$ associated to any pointed locally fibrant connected simplicial sheaf $(X, z)$ on a pointed locally connected small Grothendieck site $(\mc{C}, x)$ is studied. It is shown that this type $T(X, z)$ specializes to the \'etale ... More On realization graphs of degree sequencesMar 20 2015Mar 15 2016Given the degree sequence $d$ of a graph, the realization graph of $d$ is the graph having as its vertices the labeled realizations of $d$, with two vertices adjacent if one realization may be obtained from the other via an edge-switching operation. We ... More On fractional realizations of graph degree sequencesOct 03 2013We introduce fractional realizations of a graph degree sequence and a closely associated convex polytope. Simple graph realizations correspond to a subset of the vertices of this polytope. We describe properties of the polytope vertices and characterize ... More Variables separated equations: Strikingly different roles for the Branch Cycle Lemma and the Finite Simple Group ClassificationDec 23 2010Aug 11 2011H. Davenport's Problem asks: What can we expect of two polynomials, over the integers, with the same ranges on almost all residue class fields? This stood out among many separated variable problems posed by Davenport, D.J. Lewis and A. Schinzel. By bounding ... Moremath.NTmath.AGmath.GRPrimary 11G18, 141130, 14H25, 14M41, 20B15, 20C15, 30F10, Secondary
11R58, 12D05, 12E30, 12F10, 20E22 An Experiment with Hierarchical Bayesian Record LinkageDec 20 2012In record linkage (RL), or exact file matching, the goal is to identify the links between entities with information on two or more files. RL is an important activity in areas including counting the population, enhancing survey frames and data, and conducting ... More Dynamical Lorentz symmetry breaking and topological defectsAug 10 2010Aug 13 2010I discuss the possibility of topological defect solutions in field theories containing a tensor field which spontaneously breaks Lorentz symmetry. I find that for theories of a tensor with rank r <= 5 and for which the vacuum manifold consists of the ... More How Uniform is the Uniform Distribution on Permutations?Jan 10 2019Feb 26 2019For large $q$, does the (discrete) uniform distribution on the set of $q!$ permutations of the vector $(1,2,\dots,q)$ closely approximate the (continuous) uniform distribution on the $(q-2)$-sphere that contains them? These permutations comprise the vertices ... More The Coma - Leo I Distance Ratio and the Hubble ConstantMar 05 1997The diameter - velocity dispersion relation in B, V, and K for three early-type galaxies in the Leo I (M96) group is derived from published photometry and kinematic data. The relations in all three colors have slopes which agree well with those for the ... More How Uniform is the Uniform Distribution on Permutations?Jan 10 2019Mar 05 2019For large $q$, does the (discrete) uniform distribution on the set of $q!$ permutations of the vector $(1,2,\dots,q)$ closely approximate the (continuous) uniform distribution on the $(q-2)$-sphere that contains them? These permutations comprise the vertices ... More Moduli of relatively nilpotent extensionsOct 22 2009Gives the most precise available description of the p-Frattini module for any p-perfect finite group G=G_0 (Thm. 2.8), and therefore of the groups G_{k,ab}, k \ge 0, from which we form the abelianized M(odular) T(ower). \S 4 includes a classification ... More Relating two genus 0 problems of John ThompsonOct 20 2009The "relating" entwines three problems: 1. Davenport's Problem, describing pairs of polynomials over Q whose ranges on Z/p are the same for almost all p. 2. Showing that the monodromy groups of rational function maps over the complexes are limited to ... More Alternating groups and moduli space lifting InvariantsNov 20 2006Nov 07 2009Main Theorem: Spaces of r-branch point 3-cycle covers, degree n or Galois of degree n!/2 have one (resp. two) component(s) if r=n-1 (resp. r\ge n). Improves Fried-Serre on deciding when sphere covers with odd-order branching lift to unramified Spin covers. ... More Generalized bumblebee models and Lorentz-violating electrodynamicsSep 17 2009Feb 05 2010The breaking of Lorentz symmetry via a dynamical mechanism, with a tensor field which takes on a non-zero expectation value in vacuum, has been a subject of significant research activity in recent years. In certain models of this type, the perturbations ... More Vector models of gravitational Lorentz symmetry breakingMar 12 2009Jun 08 2009Spontaneous Lorentz symmetry breaking can occur when the dynamics of a tensor field cause it to take on a non-zero expectation value in vacuo, thereby providing one or more "preferred directions" in spacetime. Couplings between such fields and spacetime ... More Designs for a large-aperture telescope to map the CMB 10X fasterNov 14 2015Feb 24 2016Current large-aperture cosmic microwave background (CMB) telescopes have nearly maximized the number of detectors that can be illuminated while maintaining diffraction-limited image quality. The polarization-sensitive detector arrays being deployed in ... More Weakly threshold graphsAug 03 2016We define a weakly threshold sequence to be a degree sequence $d=(d_1,\dots,d_n)$ of a graph having the property that $\sum_{i \leq k} d_i \geq k(k-1)+\sum_{i > k} \min\{k,d_i\} - 1$ for all positive $k \leq \max\{i:d_i \geq i-1\}$. The weakly threshold ... More Nonabelian $H^1$ and the Étale van Kampen TheoremFeb 18 2010Generalized \'etale homotopy pro-groups $\pi_1^{\ets}(\mc{C}, x)$ associated to pointed connected small Grothendieck sites $(\mc{C}, x)$ are defined and their relationship to Galois theory and the theory of pointed torsors for discrete groups is explained. ... More On 2-switches and isomorphism classesOct 22 2011A 2-switch is an edge addition/deletion operation that changes adjacencies in the graph while preserving the degree of each vertex. A well known result states that graphs with the same degree sequence may be changed into each other via sequences of 2-switches. ... More Weakly threshold graphsAug 03 2016May 21 2018We define a weakly threshold sequence to be a degree sequence $d=(d_1,\dots,d_n)$ of a graph having the property that $\sum_{i \leq k} d_i \geq k(k-1)+\sum_{i > k} \min\{k,d_i\} - 1$ for all positive $k \leq \max\{i:d_i \geq i-1\}$. The weakly threshold ... More Adjacency relationships forced by a degree sequenceJul 31 2015There are typically several nonisomorphic graphs having a given degree sequence, and for any two degree sequence terms it is often possible to find a realization in which the corresponding vertices are adjacent and one in which they are not. We provide ... More Lorentz-violating gravity and the bootstrap procedureJul 29 2019In conventional gravitational physics, the so-called "bootstrap procedure" can be used to extrapolate from a linear model of a rank-2 tensor to a full non-linear theory of gravity (i.e., general relativity) via a coupling to the stress-energy of the model. ... More The Ghosts of Galaxies: Tidal Debris in ClustersOct 16 2003Gravitational interactions in rich clusters can strip material from the outer parts of galaxies or even completely disrupt entire systems, giving rise to large scale, low surface brightness ghostly features stretching across intergalactic space. The nearby ... More A Lack of Planets in 47 Tucanae from an HST SearchSep 25 2000Oct 11 2000We report results from a large Hubble Space Telescope project to observe a significant (~34,000) ensemble of main sequence stars in the globular cluster 47 Tucanae with a goal of defining the frequency of inner-orbit, gas-giant planets. Simulations based ... More Network Models of Photonic Floquet Topological InsulatorsNov 19 2013A recently-proposed class of photonic topological insulators is shown to map onto Chalker-Coddington-type networks, which were originally formulated to study disordered quantum Hall systems. Such network models are equivalent to the Floquet states of ... More