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Results for "A. R. L. Kavner"

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Response of CsI[Na] to Nuclear Recoils: Impact on Coherent Elastic Neutrino-Nucleus Scattering (CE$ν$NS)Jul 10 2019A new measurement of the quenching factor for low-energy nuclear recoils in CsI[Na] is presented. Past measurements are revisited, identifying and correcting several systematic effects. The resulting global data are well-described by a physics-based model ... More
Response of CsI[Na] to Nuclear Recoils: Impact on Coherent Elastic Neutrino-Nucleus Scattering (CE$ν$NS)Jul 10 2019Jul 13 2019A new measurement of the quenching factor for low-energy nuclear recoils in CsI[Na] is presented. Past measurements are revisited, identifying and correcting several systematic effects. The resulting global data are well-described by a physics-based model ... More
Measurement of low energy ionization signals from Compton scattering in a CCD dark matter detectorJun 19 2017An important source of background in direct searches for low-mass dark matter particles are the energy deposits by small-angle scattering of environmental $\gamma$ rays. We report detailed measurements of low-energy spectra from Compton scattering of ... More
A measurement of the ionization efficiency of nuclear recoils in siliconFeb 02 2017Jul 04 2017We have measured the ionization efficiency of silicon nuclear recoils with kinetic energy between 1.8 and 20 keV. We bombarded a silicon-drift diode with a neutron beam to perform an elastic-scattering experiment. A broad-energy neutron spectrum was used ... More
Status of the DAMIC direct dark matter search experimentSep 30 2015Dec 08 2015The DAMIC experiment uses fully depleted, high resistivity CCDs to search for dark matter particles. With an energy threshold $\sim$50 eV$_{ee}$, and excellent energy and spatial resolutions, the DAMIC CCDs are well-suited to identify and suppress radioactive ... More
The CONNIE experimentAug 04 2016Oct 10 2016The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos from a nuclear reactor with silicon nuclei.This talk, ... More
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLABJul 25 2016We present results of a dark matter search performed with a 0.6 kg day exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measured the energy spectrum of ionization events in the bulk silicon of charge-coupled devices (CCDs) down ... More
First direct detection constraints on eV-scale hidden-photon dark matter with DAMIC at SNOLABNov 09 2016We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30 eV$c^{-2}$ with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of ... More
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLABJul 25 2016Nov 10 2016We present results of a dark matter search performed with a 0.6 kg day exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the bulk silicon of charge-coupled devices down to a signal ... More
The DAMIC dark matter experimentOct 07 2015The DAMIC (Dark Matter in CCDs) experiment uses high resistivity, scientific grade CCDs to search for dark matter. The CCD's low electronic noise allows an unprecedently low energy threshold of a few tens of eV that make it possible to detect silicon ... More
Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experimentJun 08 2015Jul 09 2015We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of ... More
First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLABNov 09 2016Apr 11 2017We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30 eV$c^{-2}$ with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of ... More
Casimir buoyancyJan 21 2005Jun 06 2005We study the Casimir force on a single surface immersed in an inhomogeneous medium. Specifically we study the vacuum fluctuations of a scalar field with a spatially varying squared mass, $m^{2}+\lambda\Delta(x-a)+V(x)$, where $V$ is a smooth potential ... More
Magnetic fields in massive star forming regionsSep 03 2007We present the largest sample of high-mass star-forming regions observed using submillimetre imaging polarimetry. The data were taken using SCUBA in conjunction with the polarimeter on the JCMT in Hawaii. In total, 16 star forming regions were observed, ... More
Phenomenological models of two-particle correlation distributions on transverse momentum in relativistic heavy-ion collisionsJun 29 2018Feb 18 2019Two-particle, pair-number correlation distributions on two-dimensional transverse momentum ($p_{t1},p_{t2}$) constructed from the particle production in relativistic heavy-ion collisions allow access to dynamical processes in these systems beyond what ... More
Antideuteron Limits on Decaying Dark Matter with a Tuned Formation ModelFeb 25 2014May 14 2014We investigate the production of antideuterons from decaying dark matter, using gravitinos in supersymmetric models with trilinear R-parity violating (RPV) operators as an example. The model used for antideuteron formation is shown to induce large uncertainties ... More
Dynamical Lorentz simmetry breaking from 3+1 Axion-Wess-Zumino modelJun 27 1998We study the renormalizable abelian vector-field models in the presence of the Wess-Zumino interaction with the pseudoscalar matter. The renormalizability is achieved by supplementing the standard kinetic term of vector fields with higher derivatives. ... More
Heat conduction in relativistic neutral gases revisitedSep 30 2010The kinetic theory of dilute gases to first order in the gradients yields linear relations between forces and fluxes. The heat flux for the relativistic gas has been shown to be related not only to the temperature gradient but also to the density gradient ... More
Thermodynamic properties of a rewritable artificial spin iceMar 20 2019In this paper we conduct Monte Carlo simulations to investigate the thermodynamic properties of a novel geometry of artificial spin ice recently proposed in the literature that had been termed `rewritable' spin ice, for its experimental realization allows ... More
Emergence of skyrmion lattices and bimerons in diluted chiral magnetic thin filmsAug 13 2013Skyrmions are topologically protected field configurations with particle-like properties that play important roles in various fields of science. Recently, skyrmions have been directly observed in chiral magnets. Here, we investigate the effects of nonmagnetic ... More
Astrometry and photometry with HST-WFC3. I. Geometric distortion corrections of F225W, F275W, F336W bands of the UVIS-channelOct 16 2009An accurate geometric distortion solution for the Hubble Space Telescope UVIS-channel of Wide Field Camera 3 is the first step towards its use for high precision astrometry. In this work we present an average correction that enables a relative astrometric ... More
Ground-based CCD astrometry with wide field imagers. IV. An improved Geometric Distortion Correction for the Blue prime-focus Camera at the LBTMay 05 2010High precision astrometry requires an accurate geometric distortion solution. In this work, we present an average correction for the Blue Camera of the Large Binocular Telescope which enables a relative astrometric precision of ~15 mas for the B_Bessel ... More
Enlarged geometries of gauge bundlesJul 20 2001The geometrical picture of gauge theories must be enlarged when a gauge potential ceases to behave like a connection, as it does in electroweak interactions. When the gauge group has dimension four, the vector space isomorphism between spacetime and the ... More
The Recycler Electron CoolerJun 13 2013The Recycler Electron cooler was the first (and so far, the only) cooler working at a relativistic energy ({\gamma} = 9.5). It was successfully developed in 1995-2004 and was in operation at Fermilab in 2005-2011, providing cooling of antiprotons in the ... More
Identification of Moving Groups and Member Selection using Hipparcos DataMar 16 1999A new method to identify coherent structures in velocity space --- moving groups --- in astrometric catalogues is presented: the Spaghetti method. It relies on positions, parallaxes, and proper motions and is ideally suited to search for moving groups ... More
Tentative Structural Features of a Gapped RVB State in the Anisotropic Triangular LatticeNov 30 2011The self-consistency equations for the independent order parameters as well as the free energy expression for the mean-field RVB model of the spin-1/2 Heisenberg Hamiltonian on the anisotropic triangular lattice is considered in the quasi-one-dimensional ... More
Casimir Effects: an Optical Approach II. Local Observables and Thermal CorrectionsJul 04 2005We recently proposed a new approach to the Casimir effect based on classical ray optics (the "optical approximation"). In this paper we show how to use it to calculate the local observables of the field theory. In particular we study the energy-momentum ... More
The Casimir Effect and Geometric OpticsOct 31 2003Mar 17 2004We propose a new approach to the Casimir effect based on classical ray optics. We define and compute the contribution of classical optical paths to the Casimir force between rigid bodies. We reproduce the standard result for parallel plates and agree ... More
Fourier Duality as a Quantization PrincipleAug 27 1996Feb 17 1997The Weyl-Wigner prescription for quantization on Euclidean phase spaces makes essential use of Fourier duality. The extension of this property to more general phase spaces requires the use of Kac algebras, which provide the necessary background for the ... More
Higher N-point Amplitudes in Open Superstring TheoryNov 30 2006In this work we report on recent progress in the calculation of open superstring scattering amplitudes, at tree level, with more than four external massless states. We also report on the corresponding terms in the low energy effective lagrangian.
On computational issues for stability analysis of LPV systems using parameter dependent Lyapunov functions and LMIsFeb 02 2018This paper deals with the robust stability analysis of linear systems, subject to time-varying parameters. The Parameter Dependent Lyapunov Function are considered, assuming that the temporal derivative of the parameters are bounded. Some computational ... More
c-a-ca Mean Field RVB Model of CuNCN Physics. Structure Manifestations of the RVB TransitionsApr 09 2013We propose a new form of the frustrated Heisenberg antiferromagnetic Hamiltonian with spatially anisotropic exchange parameters Jc, Ja, and Jac extended along the c, a, and a +/- c lattice directions and apply it to describe fascinating physics of copper ... More
Casimir Effects: An Optical Approach I. Foundations and ExamplesJun 07 2004Jun 30 2004We present the foundations of a new approach to the Casimir effect based on classical ray optics. We show that a very useful approximation to the Casimir force between arbitrarily shaped smooth conductors can be obtained from knowledge of the paths of ... More
On the relative Galois module structure of rings of integers in tame extensionsOct 17 2014Jul 11 2018Let $F$ be a number field with ring of integers $O_F$ and let $G$ be a finite group. We describe an approach to the study of the set of realisable classes in the locally free class group $Cl(O_FG)$ of $O_FG$ that involves applying the work of the second-named ... More
Generalized drift-diffusion model for miniband superlatticesOct 20 2003A drift-diffusion model of miniband transport in strongly coupled superlattices is derived from the single-miniband Boltzmann-Poisson transport equation with a BGK (Bhatnagar-Gross-Krook) collision term. We use a consistent Chapman-Enskog method to analyze ... More
Baryon photo-decay amplitudes at the poleApr 15 2013We derive relations for baryon photo-decay amplitudes both for the Breit-Wigner and the pole positions. With an updated SAID partial wave analysis, technically similar to the earliest Virginia Tech analysis of photoproduction data, we compare photo-decay ... More
Ripples in a string coupled to Glauber spinsSep 30 2011Each oscillator in a linear chain (a string) interacts with a local Ising spin in contact with a thermal bath. These spins evolve according to Glauber dynamics. Below a critical temperature, a rippled state in the string is accompanied by a nonzero spin ... More
Summary of Fermilab's Recycler Electron Cooler Operation and StudiesJan 23 2013Fermilab's Recycler ring was used as a storage ring for accumulation and subsequent manipulations of 8-GeV antiprotons destined for the Tevatron collider. To satisfy these missions, a unique electron cooling system was designed, developed and successfully ... More
Projective Fourier Duality and Weyl QuantizationAug 27 1996Mar 17 1997The Weyl-Wigner correspondence prescription, which makes large use of Fourier duality, is reexamined from the point of view of Kac algebras, the most general background for noncommutative Fourier analysis allowing for that property. It is shown how the ... More
On the relative Galois module structure of rings of integers in tame extensionsOct 17 2014Apr 17 2015Let $F$ be a number field with ring of integers $O_F$ and let $G$ be a finite group. We describe an approach to the study of the set of realisable classes in the locally free class group $Cl(O_FG)$ of $O_FG$ that involves applying the work of the second-named ... More
Yang-Mills fields as optical mediaJul 27 2001A geometrization of the Yang-Mills field, by which an SU(2) gauge theory becomes equivalent to a 3-space geometry - or optical system - is examined. In a first step, ambient space remains Euclidean and current problems on flat space can be looked at from ... More
Wu-Yang ambiguity in connection spaceOct 12 2004Two distinct gauge potentials can have the same field strength, in which case they are said to be ``copies'' of each other. The consequences of this possibility for the general space A of gauge potentials are examined. Any two potentials are connected ... More
Comment on ``Evidence for Narrow Baryon Resonances in Inelastic pp Scattering''Jan 27 1998Compton scattering data are sensitive to the existence of low-mass resonances reported by Tatischeff et al. We show that such states, with their reported properties, are excluded by previous Compton scattering experiments.
Supplementary Material to the Comment on "Photoluminescence Ring Formation in Coupled Quantum Wells: Excitonic Versus Ambipolar Diffusion"Mar 05 2010This is a supplementary material to our Comment arXiv:0909.4265 on M. Stern, V. Garmider, E. Segre, M. Rappaport, V. Umansky, Y. Levinson, and I. Bar-Joseph, Phys. Rev. Lett. 101, 257402 (2008).
Stochastic dynamics of model proteins on a directed graphNov 19 2008A method for reconstructing the energy landscape of simple polypeptidic chains is described. We show that we can construct an equivalent representation of the energy landscape by a suitable directed graph. Its topological and dynamical features are shown ... More
Spacetime algebraic skeletonJul 10 2002Jul 10 2002The cosmological constant Lambda, which has seemingly dominated the primaeval Universe evolution and to which recent data attribute a significant present-time value, is shown to have an algebraic content: it is essentially an eigenvalue of a Casimir invariant ... More
On the Properties of the Longitudinal RVB State in the Anisotropic Triangular Lattice. Mean-Field RVB Analytical ResultsAug 01 2010Aug 27 2010The spin-1/2 Heisenberg model on an anisotropic triangular lattice is considered in the mean-field RVB approximation. The analytical estimates for the critical temperatures of the longitudinal s-RVB state (the upper one) and the 2D s-RVB state (the lower ... More
A Firm Upper Limit to the Radius of the Neutron Star in SAX J1808.4-3658Aug 05 1998Aug 08 1998We show that observations of X-ray pulsing from SAX J1808.4-3658 place a firm upper limit of 13.8 m^{1/3} km on the radius of the neutron star, where m is its mass in solar units. The limit is independent of distance or assumptions about the magnetospheric ... More
Elastic hadron-nucleus scattering in neutrino-nucleus reactions and transverse kinematics measurementsJun 25 2019Rescattering following a neutrino-nucleus reaction changes the number, energy, and direction of detectable hadrons. In turn, this affects the selection and kinematic distributions of subsamples of neutrino events used for interaction or oscillation analysis. ... More
He-Accreting WDs: accretion regimes and final outcomesSep 11 2014The behaviour of carbon-oxygen white dwarfs (WDs) subject to direct helium accretion is extensively studied. We aim to analyze the thermal response of the accreting WD to mass deposition at different time scales. The analysis has been performed for initial ... More
A Feature Clustering Approach Based on Histogram of Oriented Optical Flow and SuperpixelsFeb 28 2018Visual feature clustering is one of the cost-effective approaches to segment objects in videos. However, the assumptions made for developing the existing algorithms prevent them from being used in situations like segmenting an unknown number of static ... More
An Alternative Formation Model for Antideuterons from Dark MatterApr 27 2015Aug 13 2015Antideuterons are a potential messenger for dark matter annihilation or decay in our own galaxy, with very low backgrounds expected from astrophysical processes. The standard coalescence model of antideuteron formation, while simple to implement, is shown ... More
Resonance signals in pion-nucleon scattering from speed plots and time delayAug 04 2008Aug 15 2008We compare a number of methods used to locate resonances. These include the speed plot, the time-delay method of Eisenbud and Wigner, the time-delay matrix of Smith, and a modification by Ohmura. Numerical results show a consistency not previously reported. ... More
Intermediate phase and pseudo-phase transition in an artificial spin ice modelMar 20 2019Apr 01 2019In this paper we conduct Monte Carlo simulations to investigate the thermodynamic properties of a novel geometry of artificial spin ice recently proposed in the literature that had been termed "rewritable" spin ice, for its experimental realization allows ... More
Relativistic heat conduction: the kinetic theory approach and comparison with Marle's modelOct 07 2010In order to close the set of relativistic hydrodynamic equations, constitutive relations for the dissipative fluxes are required. In this work we outline the calculation of the corresponding closure for the heat flux in terms of the gradients of the independent ... More
Lévy walks and scaling in quenched disordered mediaMar 10 2010Apr 17 2011We study L\'evy walks in quenched disordered one-dimensional media, with scatterers spaced according to a long-tailed distribution. By analyzing the scaling relations for the random-walk probability and for the resistivity in the equivalent electric problem, ... More
Strings on pp-waves and Hadrons in (softly broken) N=1 gauge theoriesJul 04 2003We study the Penrose limit of Type IIB duals of softly broken N=1 SU(N) gauge theories in four dimensions, obtained as deformations of the Maldacena-Nunez and Klebanov-Strassler backgrounds. We extract the string spectrum on the resulting pp-wave backgrounds ... More
Parity Doubling Among the BaryonsFeb 01 2006Aug 26 2006We study the evidence for and possible origins of parity doubling among the baryons. First we explore the experimental evidence, finding a significant signal for parity doubling in the non-strange baryons, but little evidence among strange baryons. Next ... More
Excitation of the dissipationless Higgs mode in a fermionic condensateApr 10 2007The amplitude mode of a fermionic superfluid, analogous to the Higgs Boson, becomes undamped in the strong coupling regime when its frequency is pushed inside the BCS energy gap. We argue that this is the case in cold gases due to the energy dispersion ... More
Neutron star structure in a quark model with excluded volume correctionNov 12 2002Sep 30 2003We study the effects of the finite size of baryons on the equation of state of homogeneous hadronic matter. The finite extension of hadrons is introduced in order to improve the performance of field theoretical models at very high densities. We simulate ... More
Propagation of mesons in asymmetric nuclear matter in a density dependent coupling modelFeb 13 2001We study the propagation of the light mesons sigma, omega, rho, and a0(980) in dense hadronic matter in an extended derivative scalar coupling model. Within the scheme proposed it is possible to unambiguously define effective density-dependent couplings ... More
The supersymmetric Penrose transform in six dimensionsDec 26 2012We give a supersymmetric extension to the six-dimensional Penrose transform and give an integral formula for the on-shell (0, 2) supermultiplet. The relationship between super fields on space-time and twistor space is clarified and the space-time superfield ... More
Boron: a Hunt for Superhard PolymorphsNov 17 2009Boron is a unique element, being the only element, all known polymorphs of which are superhard, and all of its crystal structures are distinct from any other element. The electron-deficient bonding in boron explains its remarkable sensitivity to even ... More
Neel order in square and triangular lattice Heisenberg modelsMay 18 2007May 26 2007Using examples of the square- and triangular-lattice Heisenberg models we demonstrate that the density matrix renormalization group method (DMRG) can be effectively used to study magnetic ordering in two-dimensional lattice spin models. We show that local ... More
On a continuous mixed strategies model for evolutionary game theoryDec 14 2011We consider an integro-differential model for evolutionary game theory which describes the evolution of a population adopting mixed strategies. Using a reformulation based on the first moments of the solution, we prove some analytical properties of the ... More
Electronic band structure and Fermi surface for new layered superconductor LaO0.5F0.5BiS2 in comparison with parent phase LaOBiS2 from first principlesNov 16 2012By means of first-principles calculations? we have probed the peculiarities of the elecrtonic band structure and Fermi surface for the recently discovered layered superconductor LaO0.5F0.5BiSi2 in comparison with the parent phase LaOBiO2. The electronic ... More
Electronic band structure of novel tetragonal BiOCuS as a parent phase for novel layered superconductorsDec 02 2009Very recently, the tetragonal BiOCuS was synthesized and declared as a new superconducting system with Fe-oxypnictide - related structure. Here, based on first-principle FLAPW-GGA calculations, the structural parameters, electronic bands picture, density ... More
Elastic properties of superconducting LiFeAs from first principlesMay 19 2009The first-principles FLAPW-GGA calculations of the elastic properties of recently discovered superconducting LiFeAs are reported. The independent elastic constants (Cij), bulk modulus, compressibility, and shear modulus are evaluated and discussed. Additionally, ... More
Band structure of SrFeAsF and CaFeAsF as parent phases for a new group of oxygen-free FeAs superconductorsOct 20 2008By means of first-principle FLAPW-GGA calculations, we have investigated the electronic properties of the newly discovered layered quaternary systems SrFeAsF and CaFeAsF as parent phases for a new group of oxygen-free FeAs superconductors. The electronic ... More
Elastic properties and chemical bonding in ternary arsenide SrFe2As2 and quaternary oxyarsenide LaFeAsO - basic phases for new 38-55K superconductorsJul 22 2008We report the first-principle FLAPW-GGA calculations of the elastic properties of two related layered phases, namely, the ternary arsenide SrFe2As2 and the quaternary oxyarsenide LaFeAsO - basic phases for the newly discovered "122" and "1111" 38-55K ... More
Atomic models of non-stoichiometric layered diborides M$_{1-x}$B$_2$ (M = Mg, Al, Zr and Nb) from first principlesApr 06 2008Two atomic models of non-stoichiometric metal diborides M$_{1-x}$B$_2$ are now assumed: (i) the presence of cation vacancies and (ii) the presence of 'super-stoichiometric' boron which is placed in cation vacancy site. We have performed first principle ... More
Electronic band structure, Fermi surface and effect of spin-orbit coupling for tetragonal low-temperature superconductor Bi2Pd from first principlesAug 08 2012We have examined theoretically the electronic band structure and Fermi surface of tetragonal low-temperature superconductor Bi2Pd. Our main results are that (i) the Pd 4d and Bi 6p states determine the main peculiarities of the multiple-sheets FS topology, ... More
Electronic structure and chemical bonding in novel tetragonal phase Ca10(Pt4As8)(Fe2As2)5 as a parent material for the new family of high-TC iron-pnictide superconductorsAug 02 2011Aug 03 2011By means of first-principles calculations, the electronic structure and chemical bonding for the recently discovered tetragonal (s.g. P4/n; # 85) superconducting (Tc ~ 25K) phase Ca10(Pt4As8)(Fe2As2)5 have been examined in details, and the optimized structural ... More
Electronic band structure, Fermi surface, and elastic properties of new 4.2K superconductor SrPtAs from first-principles calculationsMay 12 2011The hexagonal phase SrPtAs (s.g. P6/mmm; #194) with a honeycomb lattice structure very recently was declared as a new low-temperature (TC ~ 4.2K) superconductor. Here by means of first-principles calculations the optimized structural parameters, electronic ... More
Elastic properties of ternary arsenide SrFe2As2 and quaternary oxyarsenide LaOFeAs as basic phases for new 38-55K superconductors from first principlesJul 07 2008Here we report the first-principle FLAPW-GGA calculations of the elastic properties of two related phases, namely, the ternary arsenide SrFe2As2 and the quaternary oxyarsenide LaOFeAs as the basic phases for the newly discovered "1111" and "122" 38-52K ... More
The Fate of the Radion in Models with Metastable GravitonApr 05 2000Aug 22 2000We clarify some general issues in models where gravity is localized at intermediate distances. We introduce the radion mode, which is usually neglected, and we point out that its role in the model is crucial. We show that the brane bending effects discussed ... More
BeppoSAX/PDS serendipitous detections at high galactic latitudesJun 10 2005At a flux limit of ~10^(-11) erg/cm2/s in the 20-100 keV band, the PDS instrument on-board BeppoSAX offers the opportunity to study the extragalactic sky with an unprecedented sensitivity. In this work we report on the results of a search in the BeppoSAX ... More
Theoretical Prediction and Impact of Fundamental Electric Dipole MomentsMay 29 2014The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases ... More
Violations of lepton flavour and CP in supersymmetric unified theoriesJan 18 1995As a consequence of the large top quark Yukawa coupling, supersymmetric unified theories with soft supersymmetry breaking terms generated at the Planck scale predict lepton flavour and CP violating processes with significant rates. The flavour violating ... More
Jet directions in Seyfert galaxies: B and I imaging dataFeb 06 2000We present the results of broad-band B and I imaging observations for a sample of 88 Seyfert galaxies (29 Seyfert 1's and 59 Seyfert 2's), selected from a mostly isotropic property, the flux at 60$\mu$m. We also present the B and I imaging results for ... More
Multidimensional Phase Space and Sunset DiagramsJan 23 2001Jul 30 2001We derive expressions for the phase-space of a particle of momentum $p$ decaying into $N$ particles, that are valid for any number of dimensions. These are the imaginary parts of so-called `sunset' diagrams, which we also obtain. The results are given ... More
The Hodge Operator RevisitedNov 16 2015Nov 19 2015We present a new construction for the Hodge operator for differential manifolds based on a Fourier (Berezin)-integral representation. We find a simple formula for the Hodge dual of the wedge product of differential forms, using the (Berezin)-convolution. ... More
Depth Development of Extensive Air Showers from Muon Time DistributionsDec 14 2004Mar 09 2005We develop a potential algorithm to relate the depth development of ultra high energy extensive air showers and the time delay for individual muons. The time distributions sampled at different positions at ground level by a large air shower array are ... More
Shape oscillations of a charged diamagnetically-levitated dropletJan 25 2012We investigate the effect of electrical charge on the normal mode frequencies of electrically-charged diamagnetically levitated water droplets with radii 4.5-7.5 mm using diamagnetic levitation. This technique allows us to levitate almost spherical droplets ... More
The ascending central series of nilpotent Lie algebras with complex structureAug 16 2017We obtain several restrictions on the terms of the ascending central series of a nilpotent Lie algebra $\mathfrak g$ under the presence of a complex structure $J$. In particular, we find a bound for the dimension of the center of $\mathfrak g$ when it ... More
Study of Ag and Cu / MgB2 powder-in-tube composite wires fabricated by in-situ reaction at low temperatureMar 22 2002Superconducting Ag or Cu sheathed MgB2 wires have been fabricated by conventional powder-in-tube techniques. The in-situ reaction of Mg and B powders with atomic proportions of 1:2 and 1.33:2 inside Ag or Cu tubes at low temperatures have been searched. ... More
A measure of physical realityNov 28 2014Nov 10 2015From the premise that an observable is real after it is measured, we envisage a tomography-based protocol that allows us to propose a quantifier for the degree of indefiniteness of an observable given a quantum state. Then, we find that the reality of ... More
Wess-Zumino and Super Yang-Mills Theories in D=4 Integral SuperspaceNov 20 2017We reconstruct the action of $N=1, D=4$ Wess-Zumino and $N=1, 2, D=4$ super-Yang-Mills theories, using integral top forms on the supermanifold ${\cal M}^{(4|4)}$. Choosing different Picture Changing Operators, we show the equivalence of their rheonomic ... More
Renormalization of the Cabibbo-Kobayashi-Maskawa MatrixApr 14 2000May 17 2000Using the on-shell scheme and the general linear R_xi gauge we have calculated the one-loop amplitude W+ -> u_I d_j. In agreement with previous work we have shown that the Cabibbo-Kobayashi-Maskawa (CKM) matrix ought to be renormalized. We show how to ... More
Gluon correlations from a Glasma flux-tube model compared to measured hadron correlations on transverse momentum $\bf (p_t,p_t)$ and angular differences $\bf (η_Δ,φ_Δ)$May 26 2011A Glasma flux-tube model has been proposed to explain strong elongation on pseudorapidity $\eta$ of the same-side 2D peak in minimum-bias angular correlations from $\sqrt{s_{NN}} = 200$ GeV \auau collisions. The same-side peak or "soft ridge" is said ... More
Velocity Dispersion of Correlated Energy Spread Electron Beams in the Free Electron LaserNov 24 2016The effects of a correlated linear energy/velocity chirp in the electron beam in the FEL, and how to compensate for its effects by using an appropriate taper (or reverse-taper) of the undulator magnetic field, is well known. The theory, as described thus ... More
An Analytical Solution for the Wigner-Boltzmann Transport Equation in the Relaxation Time ApproximationApr 29 2017Sep 18 2017The quantum version of the Boltzmann transport equation (Wigner-Boltzmann equation) is a quite useful tool to investigate the effects of energy dissipation in quantum systems. Numerical approaches uses to be employed in order to stablish a suitable solution. ... More
Bethe Ansatz solutions for Temperley-Lieb Quantum Spin ChainsMar 30 2000We solve the spectrum of quantum spin chains based on representations of the Temperley-Lieb algebra associated with the quantum groups ${\cal U}% _{q}(X_{n})$ for $X_{n}=A_{1},$ $B_{n},$ $C_{n}$ and $D_{n}$. The tool is a modified version of the coordinate ... More
The photometric study of the non-relaxed cluster "Mayer 3"Nov 12 2017Apr 21 2018The astrophysical parameters of the open star cluster Mayer 3 have been estimated using the Newtonian focus (f/4.84) of the 1.88 m Telescope of Kottamia Observatory in Egypt. The VRI observations have been carried out down to a limiting magnitude of V ... More
Compositionality, stochasticity and cooperativity in dynamic models of gene regulationFeb 08 2007Oct 09 2007We present an approach for constructing dynamic models for the simulation of gene regulatory networks from simple computational elements. Each element is called a ``gene gate'' and defines an input/output-relationship corresponding to the binding and ... More
Convergence Time to Equilibrium of the Metropolis dynamics for the GREMJun 30 2019We study the convergence time to equilibrium of the Metropolis dynamics for the Generalized Random Energy Model with an arbitrary number of hierarchical levels, a finite and reversible continuous-time Markov process, in terms of the spectral gap of its ... More
Supergravity background of lambda-deformed model for AdS2 x S2 supercosetJan 29 2016May 05 2016Starting with the F/G supercoset model corresponding to the AdS_n x S^n superstring one can define the lambda-model of arXiv:1409.1538 either as a deformation of the F/F gauged WZW model or as an integrable one-parameter generalization of the non-abelian ... More
Distortion of gamma-ray burst light curves by gravitational microlensingJan 30 1997Feb 03 1997If at cosmological distances, a small fraction of gamma-ray bursts should be multiply imaged by intervening galaxies or clusters, resulting in the appearance of two very similar bursts from the same location with a relative time delay of hours to a year. ... More
Expansion of a plasma cloud into the solar windFeb 08 2008Three-dimensional (3D) hybrid particle-in-cell (PIC) simulations, with kinetic ions and fluid electrons, of a plasma cloud expansion in the solar wind are presented, revealing the dynamics of the expansion, with shock formation, magnetic field compression, ... More
An Improved Process for Fabricating High-Mobility Organic Molecular Crystal Field-Effect TransistorsJun 21 2007In this paper we present an improved process for producing elastomer transistor stamps and high-mobility organic field-effect transistors (FETs) based on semiconducting acene molecular crystals. In particular, we have removed the need to use a silanized ... More