Results for "C. Ferreyra"

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Field-tuned order by disorder in Ising frustrated magnets with antiferromagnetic interactionsJun 09 2016Sep 30 2016We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion and Monte Carlo ... More
Oxygen vacancies dynamics in redox-based interfaces: Tailoring the memristive responseNov 23 2018Redox-based memristive devices are among the alternatives for the next generation of non volatile memories, but also candidates to emulate the behavior of synapses in neuromorphic computing devices. It is nowadays well established that the motion of oxygen ... More
Giant Memcapacitance in Topotactic Redox InterfacesMay 14 2019The possibility to develop neuromorphic computing devices able to mimic the extraordinary data processing capabilities of biological systems spurs the research on memristive systems. Memristors with additional functionalities such as robust memcapacitance ... More
TOROS Optical follow-up of the Advanced LIGO-VIRGO O2 second observational campaignJan 09 2019We present the results of the optical follow-up, conducted by the TOROS collaboration, of gravitational wave events detected during the Advanced LIGO-Virgo second observing run (Nov 2016 -- Aug 2017). Given the limited field of view ($\sim100\arcmin$) ... More
Thermodynamics of the classical spin-ice model with nearest neighbour interactions using the Wang-Landau algorithmJul 13 2015In this article we study the classical nearest-neighbour spin-ice model (nnSI) by means of Monte Carlo simulations, using the Wang-Landau algorithm. The nnSI describes several of the salient features of the spin-ice materials. Despite its simplicity it ... More
GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaborationJul 26 2016We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35-1 micron) with the 1.5-m telescope at Bosque Alegre starting ~2.5 days ... More
Tuning the electronic properties at the surface of BaBiO3 thin filmsAug 26 2015Jun 03 2016The presence of 2D electron gases at surfaces or interfaces in oxide thin films remains a hot topic in condensed matter physics. In particular, BaBiO3 appears as a very interesting system as it was theoretically proposed that its (001) surface should ... More
Small-x QCD effects in forward-jet and Mueller-Navelet jet productionOct 20 2005Mar 07 2006We investigate small-x QCD effects in forward-jet production in deep inelastic scattering in the kinematic regime where the virtuality of the photon and the transverse momentum of the jet are two hard scales of about the same magnitude. We show that the ... More
The Gravitational Radiaton degrees of freedom in Hyperbolic Systems for Numerical RelativityAug 06 2002The gravitational radiation degrees of freedom of freedom are described in the framework of the 3+1 decomposition of spacetime. The relationship with eigenfields of the Kidder-Scheel-Teukolsky (KST) equations is established. This relationship is used ... More
Approximate solutions for N-body Hamiltonians with identical particles in D dimensionsJul 19 2013Nov 13 2013A method based on the envelope theory is presented to compute approximate solutions for $N$-body Hamiltonians with identical particles in $D$ dimensions ($D\ge 2$). In some favorable cases, the approximate eigenvalues can be analytically determined and ... More
Schur-finiteness in $λ$-ringsNov 05 2010Nov 17 2011We introduce the notion of a Schur-finite element in a $\lambda$-ring.
Pion and Kaon masses in Staggered Chiral Perturbation TheoryApr 21 2003Jul 07 2003We show how to compute chiral logarithms that take into account both the $\cO(a^2)$ taste-symmetry breaking of staggered fermions and the fourth-root trick that produces one taste per flavor. The calculation starts from the Lee-Sharpe Lagrangian generalized ... More
Heavy-Light Semileptonic Decays in Staggered Chiral Perturbation TheoryApr 05 2007Jun 26 2007We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (\schpt), working to leading order in $1/m_Q$, where $m_Q$ is the heavy quark mass. We take the light ... More
Pseudoscalar Decay Constants in Staggered Chiral Perturbation TheoryJun 20 2003Sep 29 2003In a continuation of an ongoing program, we use staggered chiral perturbation theory to calculate the one-loop chiral logarithms and analytic terms in the pseudoscalar meson leptonic decay constants, $f_{\pi^+_5}$ and $f_{K^+_5}$. We consider the partially ... More
New construction of algebro-geometric solutions to the Camassa-Holm equation and their numerical evaluationSep 24 2011Dec 06 2011An independent derivation of solutions to the Camassa-Holm equation in terms of multi-dimensional theta functions is presented using an approach based on Fay's identities. Reality and smoothness conditions are studied for these solutions from the point ... More
Observations of Galaxy Clustering at High RedshiftNov 25 1998This paper reviews the current status of measurements of galaxy clustering at high redshifts (z > 0.3). The focus is on the inherent limitations in the observation and interpretation of the ``evolution of clustering''. It is likely that results from the ... More
Properties of light scalar mesons from lattice QCDApr 12 2006Jul 10 2006Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the spectrum and decay of scalar mesons. We are able to determine the $b_1$ - $a_0$ mass difference and this leads to the conclusion that the lightest non-singlet scalar meson ($a_0$) has ... More
Radio-Quiet Quasars in the Direction of the Northern Hubble Deep FieldSep 13 2000We match quasars discovered in a multi-color survey centered on the northern Hubble Deep Field (HDF) with radio sources from an ultra-deep radio survey. Although 3 out of 12 quasars are detected at a level below 0.2 mJy at 1.4 GHz, all of the quasars ... More
Super-Massive Neutron StarsNov 30 2007We present here the results of Arecibo timing of PSR B1516+02B, a 7.95-ms pulsar in a binary system with a ~0.17 solar mass companion and an orbital period of 6.85 days located in the globular cluster M5. The eccentricity of the orbit (e = 0.14) has allowed ... More
A Multi-scale Subtraction Scheme and Partial Renormalization Group Equations in the $O(N)$-symmetric $φ^4$-theoryApr 23 1996To resum large logarithms in multi-scale problems a generalization of $\MS$ is introduced allowing for as many renormalization scales as there are generic scales in the problem. In the new \lq\lq minimal multi-scale subtraction scheme'' standard perturbative ... More
Bound-free $\mathbf{e}^+ \mathbf{e}^-$ pair creation with a linearly polarized laser field and a nuclear fieldJul 28 2008The process of bound-free pair production of electrons and positrons in combined laser and Coulomb fields is investigated. It is assumed that an ion collides at relativistic speed with an intense x-ray laser beam of linear polarization. The process proceeds ... More
Mass Loss in 2D ZAMS Stellar ModelsMay 04 2011A large number of massive stars are known to rotate, resulting in significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass loss is temperature dependent, so rapid rotation produces variation in ... More
Variable Modified Newtonian Mechanics from an interpolating metric II Galactic rotational curveFeb 05 2018Feb 06 2018We use an interpolating metric from a previous work \cite{wong} with a variable modified Newtonian potential (VMOND) to explore the issue of flatten rotational curve of a galaxy. We examine a model of a large protogalactic cloud with growing density perturbation, ... More
Projective invariants of CR-hypersurfacesOct 27 2010We study the equivalence problem under projective transformation for CR-hypersurfaces of complex projective space. A complete set of projective differential invariants for analytic hypersurfaces is given. The self-dual strongly C-linearly convex hypersurfaces ... More
Modified Newtonian Mechanics 3: Pioneer acceleration anomalyJul 01 2019Using an interpolating metric between Schwarzschild and Friedmann Robertson Walker (FRW) metric (VMOND) \cite{wong}, we investigate its effect on the Pioneer Anomaly. We find that VMOND metric provides a small detectable blue-shift in the Doppler signal ... More
Hadronic matrix elements of neutral-meson mixing through lattice QCDSep 23 2015Neutral-meson mixing is loop suppressed in the Standard Model, leading to the possibility of enhanced sensitivity to new physics. The uncertainty in Standard Model predictions for $B$-meson oscillation frequencies is dominated by theoretical uncertainties ... More
Towards Automated Verification of Web ServicesNov 11 2011This paper proposes the use of model-checking software technology for the verification of workflows and business processes behaviour based on web services, namely the use of the SPIN model checker. Since the specification of a business process behaviour ... More
On the cusp form motives in genus 1 and level 1Apr 20 2005Jan 23 2006We prove that the moduli space of stable n-pointed curves of genus one and the projector associated to the alternating representation of the symmetric group on n letters define (for n>1) the Chow motive corresponding to cusp forms of weight n+1 for SL(2,Z). ... More
On some results of Cufaro Petroni about Student t-processesMar 21 2008This paper deals with Student t-processes as studied in (Cufaro Petroni N 2007 J. Phys. A, Math. Theor. 40(10), 2227-2250). We prove and extend some conjectures expressed by Cufaro Petroni about the asymptotical behavior of a Student t-process and the ... More
$K_L\toγν\barν$ in the Light Front ModelApr 17 2000We study the CP conserving and violating contributions to the decay of $\knng$ in the standard model. In our analysis, we use the form factors for $K\to\gamma$ transitions calculated directly in the entire physical range of momentum transfer within the ... More
Understanding Convolutional Neural Networks with A Mathematical ModelSep 14 2016This work attempts to address two fundamental questions about the structure of the convolutional neural networks (CNN): 1) why a non-linear activation function is essential at the filter output of every convolutional layer? 2) what is the advantage of ... More
Threshold effects in open-string theoryMay 05 1996May 14 1996We analyze the one-loop effective gauge-field action in $Z_2$-orbifold compactifications of type-I theory. We show how, for non-abelian group factors, the threshold effects are ultraviolet finite though given entirely by a six-dimensional field theory ... More
Hidden Symmetry of a Fluid Dynamical ModelMay 28 2001A connection between solutions of the relativistic d-brane system in (d+1) dimensions with the solutions of a Galileo invariant fluid in d-dimensions is by now well established. However, the physical nature of the light-cone gauge description of a relativistic ... More
A quantum topological phase transition at the microscopic levelJul 13 2007Mar 01 2008We study a quantum phase transition between a phase which is topologically ordered and one which is not. We focus on a spin model, an extension of the toric code, for which we obtain the exact ground state for all values of the coupling constant that ... More
Explicit Gravitational Radiation in Hyperbolic Systems for Numerical RelativityFeb 14 2002Feb 28 2002A method for studying the causal structure of space-time evolution systems is presented. This method, based on a generalization of the well known Riemann problem, provides intrinsic results which can be interpreted from the geometrical point of view. ... More
Flux Limiter Methods in 3D Numerical RelativityFeb 28 2002New numerical methods have been applied in relativity to obtain a numerical evolution of Einstein equations much more robust and stable. Starting from 3+1 formalism and with the evolution equations written as a FOFCH (first-order flux conservative hyperbolic) ... More
Staggered Chiral Perturbation Theory for Heavy-Light MesonsOct 18 2005Jan 25 2006We incorporate heavy-light mesons into staggered chiral perturbation theory, working to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first non-trivial order in the chiral expansion, staggered taste violations affect the chiral logarithms ... More
Replica methods for loopy sparse random graphsJan 29 2016I report on the development of a novel statistical mechanical formalism for the analysis of random graphs with many short loops, and processes on such graphs. The graphs are defined via maximum entropy ensembles, in which both the degrees (via hard constraints) ... More
Statistical Mechanics of Recurrent Neural Networks I. StaticsJun 01 2000A lecture notes style review of the equilibrium statistical mechanics of recurrent neural networks with discrete and continuous neurons (e.g. Ising, coupled-oscillators). To be published in the Handbook of Biological Physics (North-Holland). Accompanied ... More
Light-front representation of chiral dynamics with Delta isobar and large-N_c relationsMar 29 2016Transverse densities describe the spatial distribution of electromagnetic current in the nucleon at fixed light-front time. At peripheral distances b = O(M_pi^{-1}) the densities are governed by chiral dynamics and can be calculated model-independently ... More
Radio Identification of the X-ray Jet in the z=4.3 Quasar GB 1508+5714Oct 25 2003Dec 01 2003The recent discovery of an X-ray jet in the z=4.3 quasar GB 1508+5714 by Yuan et al. (astro-ph/0309318) and Siemiginowska et al. (astro-ph/0310241) prompted a search for its radio counterpart. Here, we report the successful discovery of faint radio emission ... More
CNN as Guided Multi-layer RECOS TransformJan 30 2017Feb 19 2017There is a resurging interest in developing a neural-network-based solution to the supervised machine learning problem. The convolutional neural network (CNN) will be studied in this note. To begin with, we introduce a RECOS transform as a basic building ... More
Multi-scale RenormalizationDec 18 1996The Standard MS renormalization prescription is inadequate for dealing with multi-scale problems. To illustrate this we consider the computation of the effective potential in the Higgs-Yukawa model. It is argued that it is natural to employ a two-scale ... More
Observational constraints upon quintessence models arising from moduli fieldsApr 14 2000Jun 12 2000We study observational constraints on cosmological models with a quintessence arising from moduli fields. The scalar field potential is given by a double exponential potential V=V_0 exp(-A e^{sqrt{2} kappa phi}). After reviewing the properties of the ... More
$πΛ$ phase shifts and CP Violation in ${Ξ\to πΛ}$ DecaFeb 09 2004The CP violation asymmetry parameters in $\Xi \to\pi\Lambda$ nonleptonic decays are presently being measured by the HyperCP experiment. In the study of these CP violation parameters, the strong $S$ and $P$ phase shifts for the $\pi\Lambda$ final-state ... More
$πΞ$ phase shifts and CP Violation in ${Ω\toπΞ}$ DecayMar 27 2003Apr 02 2003In the study of CP violation signals in ${\O}\to\pi\Xi$ nonleptonic decays, the strong $J$=3/2 $P$ and $D$ phase shifts for the $\pi\Xi$ final-state interactions are needed. These phases are calculated using an effective Lagrangian model, including $\Xi$, ... More
Quantum mechanics in curved space-time IISep 01 2005This paper is a sequence of the work presented in [1], where, the principles of the general relativity have been used to formulate quantum wave equations taking into account the effect of the electromagnetic and strong interactions in the space-time metric ... More
Basic Morita equivalences and a conjecture of Sasaki for cohomology of block algebras of finite groupsJun 14 2015We show, using basic Morita equivalences between block algebras of finite groups, that the Conjecture of H. Sasaki from [9] is true for a new class of blocks called nilpotent covered blocks. When this Conjecture is true we define some transfer maps between ... More
The classical overdetermined Serrin problemNov 29 2017Nov 30 2017In this survey we consider the classical overdetermined problem which was studied by Serrin in 1971. The original proof relies on Alexandrov's moving plane method, maximum principles, and a refinement of Hopf's boundary point Lemma. Since then other approaches ... More
Decay width of light quark hybrid meson from the latticeMar 06 2006Apr 13 2006Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the spectrum and decay of a $J^{PC}=1^{-+}$ spin-exotic hybrid meson. We test lattice determination of S-wave decay amplitudes at threshold using $b_1 \to \pi \omega$ where agreement with ... More
Staggered Chiral Perturbation Theory with Heavy-Light MesonsSep 08 2004We merge heavy quark effective theory with staggered chiral perturbation theory to calculate heavy-light (B, D) meson quantities. We present results at NLO for the $B(D)$ meson decay constant in the partially quenched and full QCD cases, and discuss the ... More
Transverse stability of periodic traveling waves in Kadomtsev-Petviashvili equations: A numerical studyAug 16 2011We numerically investigate transverse stability and instability of so-called cnoidal waves, i.e., periodic traveling wave solutions of the Korteweg-de Vries equation, under the time-evolution of the Kadomtsev-Petviashvili equation. In particular, we find ... More
Azimuthal decorrelation of Mueller-Navelet jets at the Tevatron and the LHCApr 25 2007Nov 05 2008We study the production of Mueller-Navelet jets at hadron colliders in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) framework. We show that a measurement of the relative azimuthal angle \Delta\Phi between the jets can provide a good testing ground for corrections ... More
High-dielectric constant and wide band gap inverse silver oxide phases of the ordered ternary alloys of SiO$_{2}$, GeO$_{2}$ and SnO$_{2}$Jul 14 2006Dec 01 2006High-dielectric constant and wide band gap oxides have important technological applications. The crystalline oxide polymorphs having lattice constant compatibility to silicon are particularly desirable. One recently reported candidate is the inverse silver ... More
Single crystal growth and anisotropy of CeRuPOSep 26 2007Dec 05 2007We report on the single crystal growth of the ferromagnetic Kondo lattice system CeRuPO using a Sn flux method. Magnetic susceptibility and electrical resistivity measurements indicate strong anisotropy of this structurally layered compound. They evidence ... More
8--13 micron spectroscopy of luminous and ultraluminous infrared galaxiesMar 17 1999New moderate-resolution mid-infrared spectroscopy at 10 micron of 27 infrared galaxies is presented. The galaxies have been chosen from three 60 micron selected and one 12 micron selected complete flux-limited catalogs of galaxies; 17 of these sources ... More
Solving the mystery of IapetusApr 29 2005Jul 19 2007For a much better-founded theory, check Wing Ip, GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L16203, doi:10.1029/2005GL025386, 2006 (see also
Transverse charge and magnetization densities in the nucleon's chiral peripheryOct 02 2013In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances ... More
Chiral dynamics and peripheral transverse densitiesAug 07 2013In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral ... More
FIRST `Winged' and `X'-shaped Radio Source CandidatesJan 10 2007Mar 16 2008A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness `wings', thus forming an overall `X'-shaped appearance. The origin of the wings in these radio sources is unclear. ... More
Compton X-ray and Gamma-ray Emission from Extended Radio GalaxiesApr 06 2007The extended lobes of radio galaxies are examined as sources of X-ray and gamma-ray emission via inverse Compton scattering of 3K background photons. The Compton spectra of two exemplary examples, Fornax A and Centaurus A, are estimated using available ... More
Panchromatic Views of Large-scale Extragalactic JetsDec 14 2006Highlights of recent observations of extended jets in AGN are presented. Specifically, we discuss new spectral constraints enabled by Spitzer, studies of the highest-redshift (z~4) radio/X-ray quasar jets, and a new VLBA detection of superluminal motion ... More
Elements stability: a microcosmos effect?Sep 13 2006The electronic structure of heavy elements, when described in a space-time which the metric is affected by the electromagnetic interaction, presents instabilities. These instabilities increase with the atomic number, and above a critical value, become ... More
Modified Newtonian Mechanics from an interpolating metricJan 04 2016Jun 22 2018A few years ago Baker \cite{baker} proposed a Lema$\hat{i}$tre-Tolman metric to interpolate smoothly between the Schwarzschild metric at small scales and the Friedmann-Robertson-Walker (FRW) metric at large scales. As it stands, by implementing the Bona-Stela ... More
Series of convex functions: subdifferential, conjugate and applications to entropy minimizationJun 03 2015A formula for the sub\-differential of the sum of a series of convex functions defined on a Banach space was provided by X. Y. Zheng in 1998. In this paper, besides a slight extension to locally convex spaces of Zheng's results, we provide a formula for ... More
Torsion cohomology classes and algebraic cycles on complex projective manifoldsMar 16 2004Jan 15 2005Atiyah and Hirzebruch gave examples ofeven degree torsion classes in the singularcohomology of a smooth complex projective manifold, which arenot Poincar\'{e} dual to an algebraiccycle. We notice that the order ofthese classes are small comparedto the ... More
Study of $B_{s}\to (η,η',φ)\ell\bar{\ell}$ DecaysMar 28 2003We study the rare decays of $B_{s} \to M_s\ell \bar{\ell}$ ($M_s=\eta, \eta',\phi$ and $\ell=\nu,e,\mu,\tau$) in the standard model. With the hadronic form factors evaluated in the light front and constituent quark models, we estimate the decay branching ... More
Spectral Mackey functors and equivariant algebraic K-theory (I)Apr 01 2014Jun 01 2014Spectral Mackey functors are homotopy-coherent versions of ordinary Mackey functors as defined by Dress. We show that they can be described as excisive functors on a suitable infinity-category, and we use this to show that universal examples of these ... More
On the Q construction for exact quasicategoriesJan 21 2013Jul 04 2013We prove that the K-theory of an exact quasicategory can be computed via a higher categorical variant of the Q construction. This construction yields a quasicategory whose weak homotopy type is a delooping of the K-theory space. We show that the direct ... More
Disorder effects in diluted magnetic semiconductorsNov 03 2003Dec 04 2003In recent years, disorder has been shown to be crucial for the understanding of diluted magnetic semiconductors. Effects of disorder in these materials are reviewed with the emphasis on theoretical works. The types and spatial distribution of defects ... More
The two-loop MHV amplitudes in N=4 supersymmetric Yang-Mills theoryAug 17 2009We compute the even part of the planar two-loop MHV amplitude in N=4 supersymmetric Yang-Mills theory, for an arbitrary number of external particles. The answer is expressed as a sum of conformal integrals.
Observable Gravitational Waves From Kinetically Modified Non-Minimal InflationOct 08 2015We consider Supersymmetric (SUSY) and non-SUSY models of chaotic inflation based on the simplest power-law potential with exponents n=2 and 4. We propose a convenient non-minimal coupling to gravity and a non-minimal kinetic term which ensure, mainly ... More
Induced-Gravity Inflation in Supergravity Confronted with Planck 2015 & BICEP2/Keck ArrayJun 11 2015Aug 31 2015Supersymmetric versions of induced-gravity inflation are formulated within Supergravity (SUGRA) employing two gauge singlet chiral superfields. The proposed superpotential is uniquely determined by applying a continuous R and a discrete Z_2 symmetry. ... More
Reducing the spectral index in F-term hybrid inflationOct 16 2007Sep 11 2008We consider a class of well motivated supersymmetric models of F-term hybrid inflation (FHI) which can be linked to the supersymmetric grand unification. The predicted scalar spectral index n_s cannot be smaller than 0.97 and can exceed unity including ... More
Combining F-Term Hybrid Inflation With a Peccei-Quinn Phase TransitionJul 26 2012We consider an inflationary model based only on renormalizable superpotential terms in which a superheavy scale F-term hybrid inflation (FHI) is followed by a Peccei-Quinn (PQ) phase transition. We show that the field which triggers the PQ phase transition ... More
Graphical analysis of Current-Voltage Characteristics in Memristive InterfacesSep 14 2016Sep 20 2016A graphical representation based on the isothermal current-voltage (IV) measurements of typical memristive interfaces is presented. This is the starting point to extract relevant microscopic information of the parameters that control the electrical properties ... More
Indirect search of exotic mesons: B -> J/psi + AnythingJul 15 2011We reconsider the discrepancy between theory and data in the momentum distribution of slow J/psi in B decays. Beside an update of the standard color singlet and color octet QCD components, we include the contribution from XY Z exotic mesons, and show ... More
Relaxed Highest Weight Modules from $\mathcal{D}$-Modules on the Kashiwara Flag SchemeJul 21 2016The relaxed highest weight representations introduced by Feigin et al. are a special class of representations of the affine Kac-Moody algebra $\hat{\mathfrak{sl}_2}$, which do not have a highest (or lowest) weight. We formulate a generalization of this ... More
Topological Mirrors and Quantum RingsNov 07 1991Aspects of duality and mirror symmetry in string theory are discussed. We emphasize, through examples, the importance of loop spaces for a deeper understanding of the geometrical origin of dualities in string theory. Moreover we show that mirror symmetry ... More
Discovery and photometry of the binary-lensing caustic-crossing event EROS-BLG-2000-5Mar 30 2003The EROS collaboration has developed a real time alert system, which was operational in 1999 and 2000. A very long binary-lensing caustic crossing event, EROS-BLG-2000-5, was found in the 2000 season and monitored by EROS. EROS photometric data for this ... More
A novel scenario for the production of antihyperons in relativistic heavy ion collisionsMar 29 2001We elaborate on our recent suggestion on antihyperon production in relativistic heavy ion collisions by means of multi-mesonic (fusion-type) reactions. It will be shown that the (rare) antihyperons are driven towards chemical equilibrium with pions, nucleons ... More
Projecting Massive Scalar Fields to Null InfinityMay 02 2007It is known that, in an asymptotically flat spacetime, null infinity cannot act as an initial-value surface for massive real scalar fields. Exploiting tools proper of harmonic analysis on hyperboloids and global norm estimates for the wave operator, we ... More
Large polaron formation induced by Rashba spin-orbit couplingNov 17 2009Feb 09 2010Here the electron-phonon Holstein model with Rashba spin-orbit interaction is studied for a two dimensional square lattice in the adiabatic limit. It is demonstrated that a delocalized electron at zero spin-orbit coupling localizes into a large polaron ... More
The piNN system - recent progressDec 20 2006Recent progress towards an understanding of the piNN system within chiral perturbation theory is reported. The focus lies on an effective field theory calculation and its comparison to phenomenological calculations for the reaction NN->d pi. In addition, ... More
Comment on 'Photoproduction of $η$--Mesic ${^3}$He'Aug 18 2004In a recent paper by the TAPS collaboration \cite{exp} a first measurement of a bound system of an $\eta$ meson and a ${^3}$He nucleus was reported. In this comment we critically reexamine the interpretation of the data and show that the data prefers ... More
Neutrino Wave Packets in Quantum Field TheoryMay 02 2002Jun 26 2002We present a model of neutrino oscillations in the framework of quantum field theory in which the propagating neutrino and the particles participating to the production and detection processes are described by wave packets. The neutrino state is a superposition ... More
The Phase of Neutrino OscillationsFeb 07 2002Using an analogy with the well-known double-slit experiment, we show that the standard phase of neutrino oscillations is correct, refuting recent claims of a factor of two correction. We also improve the wave packet treatment of neutrino oscillations ... More
Are there nu_mu or nu_tau in the flux of solar neutrinos on earth?Jul 30 2001Oct 10 2001Using the model independent method of Villante, Fiorentini, Lisi, Fogli, Palazzo, and the rates measured in the SNO and Super-Kamiokande solar neutrino experiment, we calculate the amount of active nu_mu or nu_tau present in the flux of solar neutrinos ... More
Four-neutrino MS^2 mixingJun 22 1999Jun 29 1999We present a simple scheme of mixing of four neutrinos that can accommodate the results of all neutrino oscillation experiments, the observed abundances of primordial elements and the current upper bound for the effective Majorana neutrino mass in neutrinoless ... More
On the implementation of CVC in weak charged-current proton-neutron transitionsJan 31 2016It is shown that the standard expression of the vector part of the hadronic matrix element in weak charged-current proton-neutron transitions is in agreement with the CVC hypothesis, contrary to a different claim in a recent paper.
Sterile Neutrino StatusNov 06 2013We review the results of global analyses of short-baseline neutrino oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes.
Differential (2+1) Jet Event Rates and Determination of alpha_s in Deep Inelastic Scattering at HERAJun 25 1998Events with a (2+1) jet topology in deep-inelastic scattering at HERA are studied in the kinematic range 200 < Q^2< 10,000 GeV^2. The rate of (2+1) jet events has been determined with the modified JADE jet algorithm as a function of the jet resolution ... More
Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERAApr 22 1998Apr 25 1998The multiplicity structure of the hadronic system X produced in deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY vertex, t, is limited to |t|<1 ... More
Evolution of ep Fragmentation and Multiplicity Distributions in the Breit FrameJul 02 1997Aug 15 1997Low x deep-inelastic ep scattering data, taken in 1994 at the H1 detector at HERA, are analysed in the Breit frame of reference. The evolution of the peak and width of the current hemisphere fragmentation function is presented as a function of Q and compared ... More
Forward Jet and Particle Production at HERASep 24 1998Single particles and jets in deeply inelastic scattering at low x are measured with the H1 detector in the region away from the current jet and towards the proton remnant, known as the forward region. Hadronic final state measurements in this region are ... More
Photo-production of psi' Mesons at HERANov 19 1997Quasi-elastic (z >0.95) photo-production of psi' mesons has been observed at HERA for photon-proton centre-of-mass energies in the range 40 to 160 GeV. The psi' mesons were identified through their decays to l+l- and to J/psi pi+ pi-, where the J/psi ... More
Thrust Jet Analysis of Deep-Inelastic Large-Rapidity-Gap EventsNov 13 1997A thrust analysis of Large-Rapidity-Gap events in deep-inelastic ep collisions is presented, using data taken with the H1 detector at HERA in 1994. The average thrust of the final states X, which emerge from the dissociation of virtual photons in the ... More
Low surface brightness galaxies mass profiles as a consequence of galactic evolutionSep 24 2010This paper presents a principal components analysis of rotation curves from a sample of low surface brightness galaxies. The physical meaning of the principal components is investigated, and related to the intrinsic properties of the galaxies. The rotation ... More
Unbiased reconstruction of the mass function using microlensing survey dataApr 05 2000The large number of microlensing events discovered towards the Galactic Bulge bears the promise to reconstruct the stellar mass function. The more interesting issue concerning the mass function is certainly to probe its low mass end. However due to the ... More
Reconstructing the cosmic Horseshoe gravitational lens using the singular perturbative approachJul 05 2016The cosmic horseshoe gravitational lens is analyzed using the perturbative approach. The two first order perturbative fields are expanded in Fourier series. The source is reconstructed using a fine adaptive grid. The expansion of the fields at order 2 ... More