Results for "D. A. Fagundes"

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Total Hadronic Cross Section and the Elastic Slope: An Almost Model-Independent ConnectionDec 21 2011Feb 01 2012An almost model-independent parametrization for the ratio of the total cross section to the elastic slope, as function of the center of mass energy, is introduced. The analytical result is based on the approximate relation of this quantity with the ratio ... More
Applicability of a Representation for the Martin's Real-Part Formula in Model-Independent AnalysesMay 01 2011Jul 29 2011Using a novel representation for the Martin's real-part formula without the full scaling property, an almost model-independent description of the proton-proton differential cross section data at high energies (19.4 GeV - 62.5 GeV) is obtained. In the ... More
Hadronic Cross Sections, Elastic Slope and Physical BoundsAug 02 2012An almost model-independent parametrization for the ratio of the total hadronic cross section to elastic slope is discussed. Its applicability in studies of asymptotia and analyses of extensive air shower in cosmic-ray physics is also outlined.
An empirical model for $pp$ scattering and geometrical scalingFeb 08 2014We present the result of an empirical model for elastic $pp$ scattering at LHC which indicates that the asymptotic black disk limit ${\cal R}=\sigel/\sigtot\rightarrow1/2$ is not yet reached and discuss the implications on classical geometrical scaling ... More
Model-independent data reductions of elastic proton-proton scatteringFeb 24 2011May 26 2011New developments in empirical analyses of the proton-proton differential cross section data at high energies are reported. Making use of an unconstrained model-independent parametrization for the scattering amplitude and two different fit procedures, ... More
Studying low-$x$ structure function models from astrophysical tau neutrinos events: double bang, lollipop and sugardaddy topologiesMar 13 2019Despite not have been yet identified by the IceCube detector, events generated from $\nu_{\tau}$ deep inelastic neutrino scattering in ice with varied topologies, such as double cascades (often called \textit{double bangs}), \textit{lollipops} and \textit{sugardaddies}, ... More
Aspects of a dynamical gluon mass approach to elastic hadron scattering at LHCDec 20 2011May 10 2012We discuss how the main features of the recent LHC data on elastic scattering can be described by a QCD-inspired formalism with a dynamical infrared mass scale. For this purpose new developments on a dynamical gluon mass approach are reported, with emphasis ... More
Testing parameters in an eikonalized dynamical gluon mass modelAug 04 2011Jan 17 2012In the framework of a dynamical gluon mass model recently developed, we investigate the effects of two essential parameters in the description of elastic $pp$ and $\bar{p}p$ data at high energies: the soft Pomeron intercept and the dynamical gluon mass. ... More
Soft edge of hadron scattering and mini-jet models for the total and inelastic pp cross-sections at LHC and beyondApr 19 2015Oct 01 2015We show that the onset and rise of QCD mini-jets provide the dynamical mechanism behind the appearance of a soft edge in pp collisions around ISR energies and thus such a soft edge is built in our mini-jet model with soft gluon resummation. Here the model ... More
p-air production cross-section and uncorrelated mini-jets processes in pp-scatteringAug 13 2014Dec 15 2014For the p-air production cross-section, we use a Glauber formalism which inputs the pp inelastic cross-section from a mini-jet model embedded in a single-channel eikonal expression, which provides the needed contribution of uncorrelated processes. It ... More
Hunting for asymptotia at LHCJan 14 2013We discuss whether the behaviour of some hadronic quantities, such as the total cross-section, the ratio of the elastic to the total cross-section, are presently exhibiting the asymptotic behaviour expected at very large energies. We find phenomenological ... More
Modeling the elastic differential cross-section at LHCJul 01 2013An empirical model for the $pp$ elastic differential cross section is proposed. Inspired by early work by Barger and Phillips, we parametrize the scattering amplitude in building blocks, comprising of two exponentials with a relative phase, supplementing ... More
Asymptotic Scenarios for the Proton's Central Opacity: An Empirical StudyOct 16 2014Oct 19 2014We present a model-independent analysis of the experimental data on the ratio $X$ between the elastic and total cross-sections from $pp$ and $\bar{p}p$ scattering in the c.m. energy interval 5 GeV - 8 TeV. Using a novel empirical parametrization for that ... More
Leading components in forward elastic hadron scattering: Derivative dispersion relations and asymptotic uniquenessMay 03 2017Nov 11 2017Forward amplitude analyses constitute an important approach in the investigation of the energy dependence of the total hadronic cross-section $\sigma_{tot}$ and the $\rho$ parameter. The standard picture indicates for $\sigma_{tot}$ a leading log-squared ... More
Bounds on the rise of total cross section from LHC7 and LHC8 dataMar 22 2017Jul 10 2017Recent measurements of the proton-proton total cross section $\sigma_{tot}$ at 7 and 8 TeV by the TOTEM and ATLAS Collaborations are characterized by some discrepant values: the TOTEM data suggest a rise of the cross section with the energy faster than ... More
Reply to "Commentary on "Total Hadronic Cross Section Data and the Froissart-Martin Bound", by Fagundes, Menon and Silva"Nov 14 2012Dec 06 2012A reply to the above mentioned commentary by M.M. Block and F. Halzen on our quoted work is presented. We answer to each point raised by these authors and argument that our data reductions, strategies and methodology are adequate to the nonlinear-fit-problem ... More
Preliminary Results on the Empirical Applicability of the Tsallis Distribution in Elastic Hadron ScatteringApr 25 2012Nov 06 2012We show that the proton-proton elastic differential cross section data at dip position and beyond can be quite well described by a parametrization based on the Tsallis distribution, with only five free fit parameters. Extrapolation of the results obtained ... More
Updating an empirical analysis on the proton's central opacity and asymptotiaMay 06 2015Jul 03 2015We present an updated empirical analysis on the ratio of the elastic (integrated) to the total cross section in the c.m. energy interval from 5 GeV to 8 TeV. As in a previous work, we use a suitable analytical parametrization for that ratio (depending ... More
On the rise of proton-proton cross-sections at high energiesAug 16 2012Apr 26 2013The rise of the total, elastic and inelastic hadronic cross sections at high energies is investigated by means of an analytical parametrization, with the exponent of the leading logarithm contribution as a free fit parameter. Using derivative dispersion ... More
Exploring central opacity and asymptotic scenarios in elastic hadron scatteringSep 14 2015Mar 07 2016In the absence of a global description of the experimental data on elastic and soft diffractive scattering from the first principles of QCD, model-independent analyses may provide useful phenomenological insights for the development of the theory in the ... More
Proton-proton forward scattering at the LHCApr 22 2019Recently the TOTEM experiment at the LHC has released measurements at $\sqrt{s} = 13$ TeV of the proton-proton total cross section, $\sigma_{tot}$, and the ratio of the real to imaginary parts of the forward elastic amplitude, $\rho$. Since them an intense ... More
Fine structure of the diffraction cone: from ISR to the LHCSep 07 2015Following earlier findings, we argue that the low-$|t|$ structure in the elastic diffractive cone, recently reported by the TOTEM Collaboration at $8$ TeV, is a consequence of the threshold singularity required by $t-$channel unitarity, such as revealed ... More
Total Hadronic Cross Section Data and the Froissart-Martin BoundDec 20 2011Sep 12 2012The energy dependence of the total hadronic cross section at high energies is investigated with focus on the recent experimental result by the TOTEM Collaboration at 7 TeV and the Froissart-Martin bound. On the basis of a class of analytical parametrization ... More
Casimir energy in multiply connected static hyperbolic UniversesSep 26 2002We generalize a previously obtained result, for the case of a few other static hyperbolic universes with manifolds of nontrivial topology as spatial sections.
A Perturbed Kantowski-Sachs Cosmological ModelJan 22 1997A numerical integration is made, starting with a Kantowski-Sachs (KS) model with an added initial perturbation at time one-tenth the age of the universe, and evolving up to the present. According to a prediction by Barrow (1989), the ratio between the ... More
A Cosmic Lattice as the Substratum of Quantum FieldsJul 14 2003Mar 29 2004A cosmology inspired structure for phase space is introduced, which leads to finitization and lattice-like discretization of position and momentum eigenvalues in a preferred, cosmic frame. Lorentz invariance is broken at very high energies, at present ... More
Generalized Thermostatistics and Wavelet Analysis of the Solar Wind and Proton Density VariabilityFeb 03 2005In this paper, we analyze the probability density function (PDF) of solar wind velocity and proton density, based on generalized thermostatistics (GT) approach, comparing theoretical results with observational data. The time series analyzed were obtained ... More
Infrared Gluon Resummation and pp total cross-sectionsMar 31 2014We address here the problem of describing both the total and the elastic proton-proton cross-section, through the four outstanding features of hadron scattering: (i) the optical point; (ii) the forward peak, (iii) the dip and (iv) the subsequent descent ... More
Inelastic cross-section and Survival Probabilities at LHC in mini-jet modelsMay 31 2017Aug 29 2017Recent results for the total and inelastic hadronic cross-sections from LHC experiments are compared with predictions from a single channel PDF driven eikonal mini-jet model and from an empirical model. The role of soft gluon resummation in the infrared ... More
Elastic pp scattering from the optical point to past the dip: an empirical parametrization from ISR to LHCJun 03 2013Jun 11 2013We describe the main features of recent LHC data on elastic pp scattering through a simple parametrization to the amplitude, inspired by a model proposed by Barger and Phillips in 1973, comprising of two exponentials with a relative phase. Despite its ... More
Coexistence of competing metabolic pathways in well-mixed populationsJun 19 2016Understanding why strains with different metabolic pathways that compete for a single limiting resource coexist is a challenging issue within a theoretical perspective. Previous investigations rely on mechanisms such as group or spatial structuring to ... More
The images of multilinear polynomials on strictly upper triangular matricesJul 24 2018The purpose of this paper is to describe the images of multilinear polynomials of arbitrary degree on the strictly upper triangular matrix algebra.
The Discontinuous Spatiality of Quantum Mechanical ObjectsApr 18 2005Jun 14 2005The quantum mechanical wave-particle dualism is analyzed and criticized, in the framework of Reichenbach's concepts of phenomenon and interphenomenon. It is suggested that the dual pictures be de-emphasized in the study of quantum theory, and that a qualitative ... More
Sources of CMB Spots in Closed Hyperbolic UniversesJul 28 2000The results of a previous paper by the author [Astrophys. J. 470, 43 (1996) are improved, through a more reliable technique for finding the location of sources whose images are on the surface of last scattering.
Addendum to Paper "Closed Spaces in Cosmology"May 29 1998May 31 1998A few corrections and comments are made upon a previously published paper by the author (Gen. Rel. Gravit. 24, 199 (1992)), on the subject of cosmological models with compact spatial sections.
Closed Spaces in CosmologyDec 22 2008Jan 13 2009This paper deals with two aspects of relativistic cosmologies with closed (compact and boundless) spatial sections. These spacetimes are based on the theory of General Relativity, and admit a foliation into space sections S(t), which are spacelike hypersurfaces ... More
On Multiple Images in Closed UniversesJul 03 1998Jul 31 1998Universes with multiconnected spatial sections predict multiple images of cosmic sources. A confusing terminology exists in the naming of these images as real ones vs. ghosts. Here an attempt is made to clarify the situation.
Memory cost for simulating all quantum correlations of the Peres-Mermin scenarioNov 22 2016Sequences of compatible quantum measurements can be contextual and any simulation with a classical model accounting for the quantum observations, needs to use some internal memory. In Ref. [New J. Phys. 13, 113011 (2011)], it was shown that simulating ... More
Suggestion on Quantum Computer CircuitsOct 25 2012Sep 30 2013For quantum computer circuits, it is proposed that they have, besides the presently used compact graphs, an expanded system of subgraphs, in line with the quantum mechanics superposition axiom. The representation of each process by these suggested graphs ... More
Exploring the global topology of the universeDec 30 2001In this talk work done by our group on cosmic topology is reviewed. It ranges from early attempts to solve a famous controversy about quasars through the multiplicity of images, to quantum cosmology in this context and an application to QED renormalization. ... More
An Infinite Number of Closed FLRW Universes for Any Value of the Spatial CurvatureNov 03 2011Dec 20 2011The Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological models are based on the assumptions of large-scale homogeneity and isotropy of the distribution of matter and energy. They are usually taken to have spatial sections that are simply connected; ... More
Airglow and magnetic field disturbances over Brazilian region during Chile tsunami (2015)Oct 22 2015In this work, we present first report on disturbances over Brazilian atmosphere on 16--17 September, 2015 following the Chile tsunami occurrence. Using all-sky imager and magnetometer located at 2330 km away from the epicenter, the presence of disturbances ... More
Cosmic Crystallography of the Second OrderDec 09 2002Jan 14 2003The cosmic crystallography method of Lehoucq et al. [1] produces sharp peaks in the distribution of distances between the images of cosmic sources. But the method cannot be applied to universes with compact spatial sections of negative curvature. We apply ... More
Orbifolds, Quantum Cosmology, and Nontrivial TopologyNov 07 2006Dec 18 2006In order to include nontrivial spatial topologies in the problem of quantum creation of a universe, it seems to be necessary to generalize the sum over compact, smooth 4-manifolds to a sum over finite-volume, compact 4-orbifolds. We consider in detail ... More
Casimir energy density in closed hyperbolic universesMay 13 2002Jun 05 2002The original Casimir effect results from the difference in the vacuum energies of the electromagnetic field, between that in a region of space with boundary conditions and that in the same region without boundary conditions. In this paper we develop the ... More
Quantum Creation of a Universe with Quasi-Hyperbolic Spatial SectionsDec 02 2003We calculate the probability of creation of a universe with space topology $S^{1}\times T_{g}$, where $S^{1}$ is the circle and $T_{g}$ is a compact hyperbolic surface of genus $g\geq 2$. We use the method of path integrals as applied to quantum cosmology. ... More
CG-content log-ratio distributions of Caenorhabditis elegans and Drosophila melanogaster mirtronsJan 25 2013Mirtrons are a special type of pre-miRNA which originate from intronic regions and are spliced directly from the transcript instead of being processed by Drosha. The splicing mechanism is better understood for the processing of mRNA for which was established ... More
Cosmic Crystallography with a PullbackJun 02 1999We present a modified version of the cosmic crystallography method, especially useful for testing closed models of negative spatial curvature. The images of clusters of galaxies in simulated catalogs are ``pulled back'' to the fundamental domain before ... More
Cosmic Crystallography in Compact Hyperbolic UniversesNov 23 1998We try to apply the cosmic crystallography method of Lehoucq, Lachieze-Rey, and Luminet to a universe model with closed spatial section of negative curvature. But the sharp peaks predicted for Einstein-de Sitter closed models do not appear in our hyperbolic ... More
On Closed Einstein-de Sitter UniversesApr 26 1997Aug 19 1997We briefly summarize the idea of cosmological models with compact, flat spatial sections. It has been suggested that, because of the COBE satellite's maps of the microwave background, such models cannot be small in the sense of Ellis, and hence are no ... More
Birth of a Closed Universe of Negative Spatial CurvatureJan 20 1998Nov 08 1998We propose a modified form of the spontaneous birth of the universe by quantum tunneling. It proceeds through topology change and inflation, to eventually become a universe with closed spatial sections of negative curvature and nontrivial global topology. ... More
On the Birth of a Closed Hyperbolic UniverseNov 27 1999Nov 17 2000We clarify and develop the results of a previous paper on the birth of a closed universe of negative spatial curvature and multiply connected topology. In particular we discuss the initial instanton and the second topology change in more detail. This ... More
Memory cost of temporal correlationsFeb 18 2019A possible notion of nonclassicality for single systems can be defined on the basis of the notion of memory cost of classically simulating probabilities observed in a temporal sequence of measurements. We further explore this idea in a theory-independent ... More
Casimir energy in a small volume multiply connected static hyperbolic pre-inflationary UniverseMar 05 2001A few years ago, Cornish, Spergel and Starkman (CSS), suggested that a multiply connected ``small'' Universe could allow for classical chaotic mixing as a pre-inflationary homogenization process. The smaller the volume, the more important the process. ... More
Images of multilinear polynomials of degree up to four on upper triangular matricesJul 25 2018Aug 22 2018We describe the images of multilinear polynomials of degree up to four on the upper triangular matrix algebra.
Structure and robustness of Sao Paulo public transport networkAug 23 2018Oct 08 2018Public Transport Networks plays a central role in cities devolopment. In big cities such system may be represented by a complex network and understand its properties is of great interest for managers and scholars. In this work, the urban public transport ... More
Evolution of urban scaling: evidence from BrazilJul 06 2018Aug 13 2018During the last years, the new science of municipalities has been established as a fertile quantitative approach to systematically understand the urban phenomena. One of its main pillars is the proposition that urban systems display universal scaling ... More
Detection of construction biases in biological databases: the case of miRBaseJul 24 2014Biological databases can be analysed as a complex network which may reveal some its underlying biological mechanisms. Frequently, such databases are identified as scale-free networks or as hierarchical networks depending on connectivity distributions ... More
First Very Low Frequency detection of short repeated bursts from magnetar SGR J1550-5418Aug 21 2010We report on the first detection of ionospheric disturbances caused by short repeated gamma-ray bursts from the magnetar SGR J1550-5418. Very low frequency (VLF) radio wave data obtained in South America clearly show sudden amplitude and phase changes ... More
Deconvolution of ASCA X-ray data: I. Spectral-imaging methodSep 28 1999In this paper we describe a self-contained method for performing the spectral-imaging deconvolution of X-ray data on clusters of galaxies observed by the ASCA satellite. Spatially-resolved spectral studies of data from this satellite require such a correction ... More
On the statistics of quantum transfer of non-interacting fermions in multi-terminal junctionsJul 15 2009Jan 12 2010Similarly to the recently obtained result for two-terminal systems, we show that there are constraints on the full counting statistics for non-interacting fermions in multi-terminal contacts. In contrast to the two-terminal result, however, there is no ... More
A determination of the QED coupling at the $Z$ poleNov 23 1994Dec 08 1994We critically examine the evaluation of the hadronic contribution to the running of the QED coupling, $\alpha$, from $Q^2=0$ to $Q^2=M_Z^2$. Using data for $e^+e^-\to{}$hadrons we find that $\alpha(M_Z^2)^{-1} = 128.99\pm 0.06$, as compared to the existing ... More
A new method for reconstructing the muon lateral distribution with an array of segmented countersNov 27 2014Although the origin of ultra high energy cosmic rays is still unknown, significant progress has been achieved in last decades with the construction of large arrays that are currently taking data. One of the most important pieces of information comes from ... More
The Rayleigh-Taylor Instability of Transition LayerFeb 05 1998New types of symmetry for the Rayleigh equation are found. For small Atwood number, an analytic solution is obtained for a smoothly varying density profile. It is shown that a transition layer with a finite width can undergo some kind of stratification. ... More
Local mechanical response in semiflexible polymer networks subjected to an axisymmetric prestressFeb 13 2013Aug 21 2013Analytical and numerical calculations are presented for the mechanical response of fiber networks in a state of axisymmetric prestress, in the limit where geometric non-linearities such as fiber rotation are negligible. This allows us to focus on the ... More
Close geodesics on regular tetrahedra in hyperbolic spaceJan 22 2018Feb 01 2018In this paper we present a necessary conditions, that simple close geodesics on regular tetrahedra in the 3-dimensional hyperbolic space must satisfy. Furthermore, we explicitly describe three classes of simple closed geodesics on regular tetrahedra in ... More
BdbServer++: A User Driven Data Location and Retrieval ToolJun 05 2003The adoption of Grid technology has the potential to greatly aid the BaBar experiment. BdbServer was originally designed to extract copies of data from the Objectivity/DB database at SLAC and IN2P3. With data now stored in multiple locations in a variety ... More
Reconstruction of air shower muon densities using segmented counters with time resolutionJun 08 2016Despite the significant experimental effort made in the last decades, the origin of the ultra-high energy cosmic rays is still largely unknown. Key astrophysical information to identify where these energetic particles come from is provided by their chemical ... More
Amplitude Noise Squeezing in Cavity-Driven Oscillations of a Mechanical ResonatorSep 24 2009Feb 02 2010We analyze the amplitude and phase noise of limit-cycle oscillations in a mechanical resonator coupled parametrically to an optical cavity driven above its resonant frequency. At a given temperature the limit-cycle oscillations have lower amplitude noise ... More
Comments on the Thermodynamics of Little String TheoryDec 28 2000Jan 16 2001We study the high energy thermodynamics of Little String Theory, using its holographic description. This leads to the entropy-energy relation $S=\beta_H E+\alpha\log E+O(1/E)$. We compute $\alpha$ and show that it is negative; as a consequence, the high ... More
Regimes of Precursor-Mediated Epitaxial GrowthDec 08 2007A discussion of epitaxial growth is presented for those situations (OMVPE, CBE, ALE, MOMBE, GSMBE, etc.) when the kinetics of surface processes associated with molecular precursors may be rate limiting. Emphasis is placed on the identification of various ... More
Non-local fluctuation correlations in active gelsFeb 18 2010Mar 18 2010Many active materials and biological systems are driven far from equilibrium by embedded agents that spontaneously generate forces and distort the surrounding material. Probing and characterizing these athermal fluctuations is essential for understanding ... More
Generation of Cosmic Magnetic Fields and Gravitational Waves at Neutrino DecouplingJun 08 2001Nov 08 2001We show that an inhomogeneous cosmological lepton number may have produced turbulence in the primordial plasma when neutrinos entered (almost) free-streaming regime. This effect may be responsible for the origin of cosmic magnetic fields and give rise ... More
Quadratic growth and critical point stability of semi-algebraic functionsSep 05 2013Dec 20 2014We show that quadratic growth of a semi-algebraic function is equivalent to strong metric subregularity of the subdifferential --- a kind of stability of generalized critical points. In contrast, this equivalence can easily fail outside of the semi-algebraic ... More
Ordering of magnetic impurities and tunable electronic properties of topological insulatorsOct 04 2010We study collective behavior of magnetic adatoms randomly distributed on the surface of a topological insulator. As a consequence of the spin-momentum locking on the surface, the RKKY-type interactions of two adatom spins depend on the direction of the ... More
Interaction-driven topological insulator states in strained grapheneDec 29 2011The electronic properties of graphene can be manipulated via mechanical deformations, which opens prospects for studying the Dirac fermions in new regimes and for new device applications. Certain natural configurations of strain generate large nearly ... More
Non-Linear Approximations to Gravitational Instability: A Comparison in Second-Order Perturbation TheoryNov 23 1993Nonlinear approximation methods such as the Zeldovich approximation, and more recently the frozen flow and linear potential approximations, are sometimes used to simulate nonlinear gravitational instability in the expanding Universe. We investigate the ... More
Theory of Initialization-Free Decoherence-Free Subspaces and SubsystemsMay 09 2005We introduce a generalized theory of decoherence-free subspaces and subsystems (DFSs), which do not require accurate initialization. We derive a new set of conditions for the existence of DFSs within this generalized framework. By relaxing the initialization ... More
Multiple Muons From Neutrino-Initiated Multi-W(Z) ProductionAug 29 1993Current underground detectors can search for multiple muons from multi-W(Z) production initiated by ultrahigh energy neutrinos from active galactic nuclei. O($\mu$b) cross sections give rise to downward going muon bundles whose features differ from those ... More
Some examples of exponentially harmonic mapsMay 15 2002The aim of this paper is to study some examples of exponentially harmonic maps. We study such maps firstly on flat euclidean and Minkowski spaces and secondly on Friedmann-Lema\^ itre universes. We also consider some new models of exponentially harmonic ... More
Noise properties of two single electron transistors coupled by a nanomechanical resonatorJun 16 2005Jun 24 2005We analyze the noise properties of two single electron transistors (SETs) coupled via a shared voltage gate consisting of a nanomechanical resonator. Working in the regime where the resonator can be treated as a classical system, we find that the SETs ... More
Close geodesics on regular tetrahedra in hyperbolic spaceJan 22 2018Apr 14 2018In this paper we present a necessary conditions, that simple close geodesics on regular tetrahedra in the 3-dimensional hyperbolic space must satisfy. Furthermore, we explicitly describe three classes of simple closed geodesics on regular tetrahedra in ... More
Maps for general open quantum systems and a theory of linear quantum error correctionFeb 14 2009We show that quantum subdynamics of an open quantum system can always be described by a Hermitian map, irrespective of the form of the initial total system state. Since the theory of quantum error correction was developed based on the assumption of completely ... More
Corrections to the Newton and Coulomb potentials caused by effects of spacetime foamAug 09 2001We use an extended quantum field theory (EQFT) hep-th/9911168 to explore possible observational effects of the spacetime. It is shown that as it was expected the spacetime foam can provide quantum bose fields with a cutoff at very small scales, if the ... More
The exclusive B_s -> phi mu+ mu- process in a constituent quark modelMay 07 2001Jun 14 2001We consider the exclusive B_s -> phi mu+ mu- process in the standard model using a constituent quark loop model approach together with a simple parameterization of the quark dynamics. The model allows to compute the decay form factors and therefore can ... More
Vector mesons in the Extended Chiral Quark ModelJun 23 1999Aug 20 1999We extend our previous formulation of low-energy QCD in terms of an effective lagrangian containing operators of dimensionality $d\le 6$ constructed with pseudoscalars and quark fields, describing physics below the scale of chiral symmetry breaking. We ... More
On the possibility of P-violation at finite baryon-number densitiesSep 01 2007Apr 18 2008We show how the introduction of a finite baryon density may trigger spontaneous parity violation in the hadronic phase of QCD. Since this involves strong interaction physics in an intermediate energy range we approximate QCD by a \sigma model that retains ... More
Sensitivity to perturbations and quantum phase transitionsMay 15 2013The local density of states or its Fourier transform, usually called fidelity amplitude, are important measures of quantum irreversibility due to imperfect evolution. In this Rapid Communication we study both quantities in a paradigmatic many body system, ... More
Cosmic Ray Signatures of Multi-W ProcessesAug 13 1993We explore the discovery potential of cosmic ray physics experiments for Standard Model processes involving the nonperturbative production of O(30) weak gauge bosons. We demonstrate an experimental insensitivity to proton-induced processes and emphasize ... More
Interaction of Ising-Bloch fronts with Dirichlet BoundariesApr 26 2004We study the Ising-Bloch bifurcation in two systems, the Complex Ginzburg Landau equation (CGLE) and a FitzHugh Nagumo (FN) model in the presence of spatial inhomogeneity introduced by Dirichlet boundary conditions. It is seen that the interaction of ... More
Boundary effects on localized structures in spatially extended systemsMar 16 2005Aug 24 2005We present a general method of analyzing the influence of finite size and boundary effects on the dynamics of localized solutions of non-linear spatially extended systems. The dynamics of localized structures in infinite systems involve solvability conditions ... More
The emergence of charged collective modes from a large N extrapolation of the Hubbard modelMay 22 2001Oct 10 2001We consider a symplectic extrapolation of the Hubbard model of N fold replicated electrons and solve this model exactly in two special cases, at N=infinity in the bosonic sector and for any N on a dimer of two points. At N=infinity we find a multiplet ... More
A one dimensional analysis of turbulence and its intermittence for the d-dimensional stochastic Burgers equationJun 08 2007The inviscid limit of the stochastic Burgers equation is discussed in terms of the level surfaces of the minimising Hamilton-Jacobi function, the classical mechanical caustic and the Maxwell set and their algebraic pre-images under the classical mechanical ... More
Multivariate approximation in total variation using local dependenceJul 18 2018We establish two theorems for assessing the accuracy in total variation of multivariate discrete normal approximation to the distribution of an integer valued random vector $W$. The first is for sums of random vectors whose dependence structure is local. ... More
Foam-like structure of the UniverseJul 02 2007Oct 08 2007On the quantum stage spacetime had the foam-like structure. When the Universe cools, the foam structure tempers and does not disappear. We show that effects caused by the foamed structure mimic very well the observed Dark Matter phenomena. Moreover, we ... More
The Universal Rotation Curve of Spiral GalaxiesApr 24 2006Jun 22 2006The observed strong dark-to-luminous matter coupling is described by a bias relation between visible and dark matter sources. We discuss the bias which emerges in the case where the topological structure of the Universe at very large distances does not ... More
Vanishing quantum discord is necessary and sufficient for completely positive mapsAug 01 2008Feb 08 2009Two long standing open problems in quantum theory are to characterize the class of initial system-bath states for which quantum dynamics is equivalent to (1) a map between the initial and final system states, and (2) a completely positive (CP) map. The ... More
Geometrical description of non-linear electrostatic oscillations in relativistic thermal plasmasJul 23 2008Jul 30 2008We develop a method for investigating the relationship between the shape of a 1-particle distribution and non-linear electrostatic oscillations in a collisionless plasma, incorporating transverse thermal motion. A general expression is found for the maximum ... More
Aspects of electromagnetic radiation reaction in strong fieldsSep 26 2014With the recent advances in laser technology, experimental investigation of radiation reaction phenomena is at last becoming a realistic prospect. A pedagogical introduction to electromagnetic radiation reaction is given with the emphasis on matter driven ... More
General random walk in a random environment defined on Galton-Watson treesFeb 17 2014Apr 29 2016We consider the motion of a particle on a Galton Watson tree, when the probabilities of jumping from a vertex to any one of its neighbours is determined by a random process. Given the tree, positive weights are assigned to the edges in such a way that, ... More