December 2002 arXiv papers — page 14

Remo Ruffini, Luca Vitagliano

The mass--energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and expression for the irreducible mass of a static black hole. It is shown that the efficiency of energy extraction process during the

Frederic Zagury

I have been too conservative in `A review of the properties of the scattered starlight which contaminates the spectrum of reddened stars' (NewA, 2002, 7/4, 191) concerning the conditions implied by an additional component of scattered light in the spectrum of reddened stars. I will review and simplify these conditions. Implications for the column density

Frederic Zagury

When a star is observed behind an interstellar cloud of sufficient column density, we do not observe the direct light from the star, which is totally extinguished. Rather, we see only starlight scattered at small angles from the star. I use several papers published in New Astronomy to recount the different steps which permit understanding how, and under whic

Frederic Zagury

In this paper I review a series of observations which do not agree with the standard interpretation of the extinction curve. The consequence is that light we receive from a reddened star must be contaminated by starlight scattered at very small angular distances from the star. The true extinction curve is a straight line from the near infrared to the far-UV.

G. Ghisellini

The power of blazar jets rivals the power that gravity can extract from accreting matter. The mechanism launching and accelerating jets can be considered as the most efficient engine operating in radio--loud sources. It is still a matter of debate if the jet carries this power to the radio lobes, hundreds of kpc away, in the form of Poynting flux or bulk kin

Mario Hamuy, Maximilian Stritzinger, M. M. Phillips, Nicholas B. Suntzeff

We present optical and infrared spectra of SN 1999ex that reveal a clear example of an intermediate Type Ib/c case. This suggests a continuous spectroscopic sequence between Type Ib and Type Ic supernovae. We report UBVRIz photometric observations of SN 1999ex that started only one day after explosion, which permitted us to witness an elusive transient cooli

Anatoly A. Svidzinsky

We find that neutron star interior is transparent for collisionless electron sound, the same way as it is transparent for neutrinos. In the presence of magnetic field the electron sound is coupled with electromagnetic radiation and form the fast magnetosonic wave. We find that electron sound is generated by superfluid vortices in the stellar core. Thermally

H. -Th. Janka, R. Buras, K. Kifonidis, M. Rampp

One of the central problems in supernova theory is the question how massive stars explode. Understanding the physical processes that drive the explosion is crucial for linking the stellar progenitors to the final remnants and for predicting observable properties like explosion energies, neutron star and black hole masses, nucleosynthetic yields, explosion an

B. C. Tiburzi, G. A. Miller

We consider two simple covariant models for pions (one with scalar and the other with spin-1/2 constituents). Pion generalized parton distributions are derived by integration over the light-cone energy. The model distributions are consistent with all known properties of generalized parton distributions, including positivity. We also construct the correspondi

A. Melikidze, V. V. Dobrovitski, H. A. De Raedt, M. I. Katsnelson

We demonstrate that decoherence of many-spin systems can drastically differ from decoherence of single-spin systems. The difference originates at the most basic level, being determined by parity of the central system, i.e. by whether the system comprises even or odd number of spin-1/2 entities. Therefore, it is very likely that similar distinction between th

Neta A. Bahcall, Paul Bode

We determine the linear amplitude of mass fluctuations in the universe, sigma_8, from the abundance of massive clusters at redshifts z=0.5 to 0.8. The evolution of massive clusters depends exponentially on the amplitude of mass fluctuations and thus provides a powerful measure of this important cosmological parameter. The relatively high abundance of massive

R. Martinez, J. -Alexis Rodriguez, M. Rozo

We consider the Two Higgs Doublet Model (2HDM) of type III which leads to Flavour Changing Neutral Currents (FCNC) at tree level. In the framework of this model we can use an appropriate form of the Yukawa Lagrangian that makes the type II model limit of the general type III couplings apparent. This way is useful in order to compare with the experimental dat

Arkady L. Kholodenko

The history of discovery of bosonic string theory is well documented. This theory evolved as an attempt to find a multidimensional analogue of Euler's beta function. Such an analogue had in fact been known in mathematics literature at least in 1922 and was studied subsequently by mathematicians such as Selberg, Weil and Deligne among others. The mathemat

R. F. Ávila, E. G. S. Luna, M. J. Menon

Analytic models for hadron-hadron scattering are characterized by analytical parametrizations for the forward amplitudes and the use of dispersion relation techniques to study the total cross section $σ_{tot}$ and the $ρ$ parameter. In this paper we investigate four aspects related to the application of the model to $pp$ and $\bar{p}p$ scattering, from accel

Andreas A. Berlind, David H. Weinberg, Andrew J. Benson, Carlton M. Baugh

The halo occupation distribution (HOD) describes the bias between galaxies and dark matter by specifying (a) the probability P(N|M) that a halo of virial mass M contains N galaxies of a particular class and (b) the relative distributions of galaxies and dark matter within halos. We calculate predicted HODs for a Lambda-CDM cosmological model using an SPH hyd

Felix M. Lev

As argued in our previous papers, it would be more natural to modify the standard approach to quantum theory by requiring that i) one unitary irreducible representation (UIR) of the symmetry algebra should describe a particle and its antiparticle simultaneously. This would automatically explain the existence of antiparticles and show that a particle and its

Li-Sheng Tseng

We discuss the action of SL(2,Z) on local operators in D=4, N=4 SYM theory in the superconformal phase. The modular property of the operator's scaling dimension determines whether the operator transforms as a singlet, or covariantly, as part of a finite or infinite dimensional multiplet under the SL(2,Z) action. As an example, we argue that operators in

Sumanta Tewari

Using an analysis similar to that of Imry and Wortis, it is shown that the apparent first order superconductor to metal transition, which has been claimed to exist at low values of the magnetic field in a two-dimensional field-tuned system at zero temperature,can be consistentlyinterpreted as a sharp crossover from a strong superconductor to an inhomogeneous

Steve Corley, Sanjaye Ramgoolam

We show that the BMN operators in D=4 N=4 super Yang Mills theory proposed as duals of stringy oscillators in a plane wave background have a natural quantum group construction in terms of the quantum deformation of the SO(6) $R$ symmetry. We describe in detail how a q-deformed U(2) subalgebra generates BMN operators, with $ q \sim e^{2 i π\over J}$. The stan

Andrzej Czarnecki, William J. Marciano, Arkady Vainshtein

Effects of strong interactions on the two loop electroweak radiative corrections to the muon anomalous magnetic moment, $a_μ=(g_μ-2)/2$, are examined. Short-distance logs are shown to be unaffected. Computation of long-distance contributions is improved by use of an effective field theory approach that preserves the chiral properties of QCD and accounts for

A. Batrachenko, M. J. Duff, J. X. Lu

The original {\it membrane at the end of the universe} corresponds to a probe $M2$-brane of signature $(2,1)$ occupying the $S^{2} \times S^{1}$ boundary of the $(10,1)$ spacetime $AdS_{4} \times S^{7}$, and is described by an $OSp(4/8)$ SCFT. However, it was subsequently generalized to other worldvolume signatures $(s,t)$ and other spacetime signatures $(S,

Arkady Vainshtein

Anomalous quark triangles with one axial and two vector currents are studied in special kinematics when one of the vector currents carries a soft momentum. According to the Adler-Bardeen theorem the anomalous longitudinal part of the triangle is not renormalized in the chiral limit. We derive a new nonrenormalization theorem for the transversal part of the t

HERMES collaboration, A. Airapetian

Single-spin asymmetries have been measured for semi-inclusive electroproduction of $π^+$, $π^-$, $π^0$ and $K^+$ mesons in deep-inelastic scattering off a longitudinally polarised deuterium target. The asymmetries appear in the distribution of the hadrons in the azimuthal angle $ϕ$ around the virtual photon direction, relative to the lepton scattering plane.

Gustavo Burdman, Maxim Perelstein, Aaron Pierce

The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles.

Yu. Kagan, L. A. Maksimov

We analyze the damping of the transverse breathing mode in an elongated trap at ultralow temperatures. The damping occurs due to the parametric resonance entailing the energy transfer to the longitudinal degrees of freedom. It is found that the nonlinear coupling between the transverse and discrete longitudinal modes can result in an anomalous behavior of th

D. Francia, A. Sagnotti

We review a recent construction of the free field equations for totally symmetric tensors and tensor-spinors that exhibits the corresponding linearized geometry. These equations are not local for all spins >2, involve unconstrained fields and gauge parameters, rest on the curvatures introduced long ago by de Wit and Freedman, and reduce to the local (Fang-)F

H. Nunokawa, W. J. C. Teves, R. Zukanovich Funchal

The neutrino oscillation experiment KamLAND has given the first evidence for disappearance of $\bar ν_e$ coming from nuclear reactors. We have combined their data with all the solar neutrino data assuming two flavor neutrino mixing and obtained allowed parameter regions which are compatible with the so-called large mixing angle MSW solution to the solar neut

Lijun Zhu, Markus Garst, Achim Rosch, Qimiao Si

At a generic quantum critical point, the thermal expansion $α$ is more singular than the specific heat $c_p$. Consequently, the "Grüneisen ratio'', $\GE=α/c_p$, diverges. When scaling applies, $\GE \sim T^{-1/(νz)}$ at the critical pressure $p=p_c$, providing a means to measure the scaling dimension of the most relevant operator that pressure cou

Luca Martucci, Pedro J. Silva

In this letter we present a derivation, from the D0-brane picture, of the background monopole field and in general of the full dynamics of the Yang-Mills theory on the dielectric D2-brane of Myers. To do this we study the large N limit of the fuzzy sphere relevant to the dielectric solution. In contrast to the usual interpretation, where the commutative D2-b

D. Dudal, H. Verschelde, S. P. Sorella

The local composite operator A^2 is analysed in pure Yang-Mills theory in the Landau gauge within the algebraic renormalization. It is proven that the anomalous dimension of A^2 is not an independent parameter, being expressed as a linear combination of the gauge beta function and of the anomalous dimension of the gauge fields.

V. V. Savkin, A. N. Rubtsov, T. Janssen

The classical two-dimensional discrete frustrated $ϕ^4$ model is studied by Monte Carlo simulations. The correlation function is obtained for two values of a parameter $d$ that determines the frustration in the model. The ground state is a ferro-phase for $d=-0.35$ and a commensurate phase with period N=6 for $d=-0.45$. Mean field predicts that at higher tem

L. Girardello, M. Porrati, A. Zaffaroni

We study a duality, recently conjectured by Klebanov and Polyakov, between higher-spin theories on AdS_4 and O(N) vector models in 3-d. These theories are free in the UV and interacting in the IR. At the UV fixed point, the O(N) model has an infinite number of higher-spin conserved currents. In the IR, these currents are no longer conserved for spin s>2. In

Roman Orus, Jose I. Latorre, Miguel A. Martin-Delgado

Motivated by the need to uncover some underlying mathematical structure of optimal quantum computation, we carry out a systematic analysis of a wide variety of quantum algorithms from the majorization theory point of view. We conclude that step-by-step majorization is found in the known instances of fast and efficient algorithms, namely in the quantum Fourie

Dan Hooper, Tilman Plehn

Using a very minimal set of theoretical assumptions we derive a lower limit on the LSP mass in the MSSM. We only require that the LSP be the lightest neutralino, that it be responsible for the observed relic density and that the MSSM spectrum respect the LEP2 limits. We explicitly do not require any further knowledge about the MSSM spectrum or the mechanism

V. V. Fernández, A. M. Moya, Waldyr A. Rodrigues

In this paper we give a comparison between the formulation of the concept of metric for a real vector space of finite dimension in terms of \emph{tensors} and \emph{extensors}. A nice property of metric extensors is that they have inverses which are also themselves metric extensors. This property is not shared by metric tensors because tensors do \emph{not}

Mario Vietri

We derive a relativistically covariant (although not manifestly so) equation for the distribution function of particles accelerated at shocks, which applies also to extremely relativistic shocks, and arbitrarily anisotropic particle distributions. The theory is formulated for arbitrary pitch angle scattering, and reduces to the well--known case for small ang

Luis Dinis, Juan M. R. Parrondo

We present a modification of the so-called Parrondo's paradox where one is allowed to choose in each turn the game that a large number of individuals play. It turns out that, by choosing the game which gives the highest average earnings at each step, one ends up with systematic loses, whereas a periodic or random sequence of choices yields a steadily inc

Roman Bertle, Manfried Faber

We review lattice evidence for the vortex mechanism of quark confinement and study the influence of charged matter fields on the vortex distribution.

A. F. Volkov, F. S. Bergeret, K. B. Efetov

We demonstrate that in multilayered superconductor-ferromagnet structures a non-collinear alignment of the magnetizations of different ferromagnetic layers generates a triplet superconducting condensate which is odd in frequency. This triplet condensate coexists in the superconductors with the conventional singlet one but decays very slowly in the ferromagne

Marek Szydlowski, Adam Krawiec

Methods of dynamical systems have been used to study homogeneous and isotropic cosmological models with a varying speed of light (VSL). We propose two methods of reduction of dynamics to the form of planar Hamiltonian dynamical systems for models with a time dependent equation of state. The solutions are analyzed on two-dimensional phase space in the variabl

Henryk Czyz, Agnieszka Grzelinska, Johann H. Kuhn, German Rodrigo

The radiative return offers the unique possibility for a measurement of the cross section of electron--positron annihilation into hadrons over a wide range of energies. The large luminosity of present phi- and B-factories easily compensates for the additional factor of alpha due to the emission of a hard photon. Final states with photons at large angles can

Jan Brugues, Joaquim Gomis, Toni Mateos, Toni Ramirez

We give the supergravity duals of commutative and noncommutative non-abelian gauge theories with N=2 in 2+1 dimensions. The moduli space on the Coulomb branch of these theories is studied using supergravity.

B. V. Martemyanov, Amand Faessler, C. Fuchs, M. I. Krivoruchenko

Kaon in-medium masses and mean-field potentials are calculated in isotopically symmetric pion matter to one loop of chiral perturbation theory. The results are extended to RHIC temperatures using experimental data on $πK$ scattering phase shifts. The kaon in-medium broadening results in an acceleration of the $ϕ\to K\bar{K}$ decay. The increased apparent dil

Chao-Shang Huang, Xiao-Hong Wu

Pure leptonic and semileptonic rare B decays, $B_s \to μ^+ μ^-$ and $B \to X_s μ^+ μ^-$ in the minimal supersymmetric Standard Model (MSSM), in particular, gluino and neutralino contributions to the decays, are discussed under Br($B \to X_s γ$) and other experimental constraints . The general scalar quark mass matrices as the new sources of flavor violation

Harvey B. Meyer, Michael J. Teper

We discuss the principles underlying higher spin glueball calculations on the lattice. For that purpose, we develop numerical techniques to rotate Wilson loops by arbitrary angles in lattice gauge theories close to the continuum. As a first application, we compute the glueball spectrum of the SU(2) gauge theory in 2+1 dimensions for both parities and for spi

M. Radici

A review of the theoretical activity in Italy in the research field of Hadronic Physics is given. Specific focus is put on phenomenological models based on the effective degrees of freedom of constituent quarks, on parton distributions in hard processes in the Bjorken limit and on the possibility of linking the two concepts via evolution equations. A brief i

F. J. Herrera-Govantes, M. A. Olalla Acosta, J. L. Vicente-Cordoba

This paper deals with valuations of fields of formal meromorphic functions and their residue fields. We explicitly describe the residue fields of the monomial valuations. We also classify all the discrete rank one valuations of fields of power series in two and three variables, according to their residue fields. We prove that all our cases are possible and g

The LEP Collaboration, ALEPH Collaboration, DELPHI Collaboration, L3 Collaboration

This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2002 summer conferences. Averages from Z resonance results are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the tau polarisation asymmetries, t

I. Tsukada, X. F. Sun, Seiki Komiya, A. N. Lavrov

The magnetic structure of (La${}_{1.8}$Eu${}_{0.2}$)CuO${}_4$ has been studied by magnetization measurements of single crystals, which show antiferromagnetic long-range order below $T_N$ = 265 K and a structural phase transition at $T_s$ = 130 K. At $T_s < T < T_N$, the Cu spin susceptibility exhibits almost the same behavior as that of La${}_2$CuO${}_4$ in

Masato Arai, Shigeo Fujita, Masashi Naganuma, Norisuke Sakai

In five-dimensional supergravity, an exact solution of BPS wall is found for a gravitational deformation of the massive Eguchi-Hanson nonlinear sigma model. The warp factor decreases for both infinities of the extra dimension. Thin wall limit gives the Randall-Sundrum model without fine-tuning of input parameters. We also obtain wall solutions with warp fact

Mirjam Cvetic, Ioannis Papadimitriou, Gary Shiu

We construct some N=1 supersymmetric three-family SU(5) Grand Unified Models from type IIA orientifolds on $\IT^6/(\IZ_2\times \IZ_2)$ with D6-branes intersecting at general angles. These constructions are supersymmetric only for special choices of untwisted moduli. We show that within the above class of constructions there are no supersymmetric three-family

Andreas Gustavsson

We show how one can get solitonic strings in a six-dimensional (2,0) supersymmetric theory by incorporating a nonlinear interaction term. We derive a zero force condition between parallel strings, and compute a metric on a moduli space which is $R^4$ when the strings are far apart. When compactifying the strings on a two-torus we show that, in the limit of v

Maria K. Koleva

A local quantum phenomenon that gives rise to generic for all surface reactions macroscopic fluctuations is studied. The issue is viewed with respect to the necessary conditions for a long-term stable evolution of any natural and artificial system. It is shown that global coupling of the local fluctuations is necessary for providing a long-term stability of

Holger F. Hofmann, Shigeki Takeuchi

Entangled states represent correlations between two separate systems that are too precise to be represented by products of local quantum states. We show that this limit of precision for the local quantum states of a pair of N-level systems can be defined by an appropriate class of uncertainty relations. The violation of such local uncertainty relations may b

Makoto Yamashita, Masato Koashi, Tetsuya Mukai, Masaharu Mitsunaga

We study the optimization of evaporative cooling in trapped bosonic atoms on the basis of quantum kinetic theory of a Bose gas. The optimized cooling trajectory for $^{87}$Rb atoms indicates that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against loss of trapped atoms caused by three-bo

D. G. Polyakov, I. V. Gornyi

We generalize the fermionic renormalization group method to describe analytically transport through a double barrier structure in a one-dimensional system. Focusing on the case of weakly interacting electrons, we investigate thoroughly the dependence of the conductance on the strength and the shape of the double barrier for arbitrary temperature T. Our appro

Y. Kurihara, J. Fujimoto, T. Ishikawa, K. Kato

A new method to construct event-generators based on next-to-leading order QCD matrix-elements and leading-logarithmic parton showers is proposed. Matrix elements of loop diagram as well as those of a tree level can be generated using an automatic system. A soft/collinear singularity is treated using a leading-log subtraction method. Higher order re-summation

Mark A. Walker, Geraint F. Lewis

All quasars vary in their optical flux on a time-scale of years, and it has been proposed that these variations are principally due to gravitational lensing by a cosmologically distributed population of planetary mass objects. This interpretation has implications for the observable properties of gamma-ray bursts (GRBs) -- as a source expands across the nano-

K. Odagiri

We consider the recent proposal that the distribution of the difference between azimuthal angles of the two accompanying jets in gluon-fusion induced Higgs-plus-two-jet events at LHC reflects the CP of the Higgs boson produced. We point out that the hierarchy between the Higgs boson mass and the jet transverse energy makes this observable vulnerable to logar

J. G. Körner, Chun Liu

A supersymmetric model with two copies of the Standard Model gauge groups is constructed in the gauge mediated supersymmetry breaking scenario. The supersymmetry breaking messengers are in a simple form. The Standard Model is obtained after first step gauge symmetry breaking. In the case of one copy of the gauge interactions being strong, a scenario of elect

Jonathan Oppenheim

New methods are presented which enables one to analyze the thermodynamics of systems with long-range interactions. Generically, such systems have entropies which are non-extensive, (do not scale with the size of the system). We show how to calculate the degree of non-extensivity for such a system. We find that a system interacting with a heat reservoir is in

Ruben Mkrtchyan

The problem of decomposition of unitary irreps of (super) tensorial (i.e. extended with tensorial charges) Poincar{é} algebra w.r.t. its different subalgebras is considered. This requires calculation of little groups for different configurations of tensor charges. Particularly, for preon states (i.e. states with maximal supersymmetry) in different dimensions

Martin Beaudry, Jose M. Fernandez, Markus Holzer

We study the computational complexity of the problem SFT (Sum-free Formula partial Trace): given a tensor formula F over a subsemiring of the complex field (C,+,.) plus a positive integer k, under the restrictions that all inputs are column vectors of L2-norm 1 and norm-preserving square matrices, and that the output matrix is a column vector, decide whether

Gerard &#39;t Hooft

Contrary to common belief, it is not difficult to construct deterministic models where stochastic behavior is correctly described by quantum mechanical amplitudes, in precise accordance with the Copenhagen-Bohr-Bohm doctrine. What is difficult however is to obtain a Hamiltonian that is bounded from below, and whose ground state is a vacuum that exhibits comp

H. Kröger

We discuss the concept of the quantum action with the purpose to characterize and quantitatively compute quantum chaos. As an example we consider in quantum mechanics a 2-D Hamiltonian system - harmonic oscillators with anharmonic coupling - which is classically a chaotic system. We compare Poincaré sections obtained from the quantum action with those from t

Ross C. O&#39;Connell

The dynamics of a quantum mechanical particle in a time-independent potential are found to contain many interesting phenomena. These are direct consequences of the (typical) existence of more than one time scale governing the problem. This gives rise to full revivals of initial wavepackets, fractional revivals (multiple wavepackets appearing at fractions of

T. Heinonen, P. Lahti, J. -P. Pellonpaa, S. Pulmannova

A normalized positive operator measure $X\mapsto E(X)$ has the norm-1-property if $\no{E(X)}=1$ whenever $E(X)\ne O$. This property reflects the fact that the measurement outcome probabilities for the values of such observables can be made arbitrary close to one with suitable state preparations. Some general implications of the norm-1-property are investigat

G. S. Agarwal, Robert W. Boyd

Using first principles, it is demonstrated that radiative damping alone cannot lead to a nonvanishing electro-optic effect in a chiral isotropic medium. This conclusion is in contrast with that obtained by a calculation in which damping effects are included using the standard phenomenological model. We show that these predictions differ because the phenomeno

Pil Hun Song, Ilki Kim

We study the effects of dissipation or leakage on the time evolution of Grover&#39;s algorithm for a quantum computer. We introduce an effective two-level model with dissipation and randomness (imperfections), which is based upon the idea that ideal Grover&#39;s algorithm operates in a 2-dimensional Hilbert space. The simulation results of this model and Gro

Natalia Vladimirova, Peter Constantin, Alexander Kiselev, Oleg Ruchayskiy

We perform direct numerical simulations (DNS) of an advected scalar field which diffuses and reacts according to a nonlinear reaction law. The objective is to study how the bulk burning rate of the reaction is affected by an imposed flow. In particular, we are interested in comparing the numerical results with recently predicted analytical upper and lower bo

Michele Gallinaro

Two Miniplug calorimeters, designed to measure the energy and lateral position of particles in the forward pseudorapidity region of 3.6<|η|<5.1, have been installed as part of the CDF upgraded detector for Run II at the Tevatron. Proton-antiproton beams are colliding at $\sqrt{s}$=1.96 TeV. One year after installation, Miniplug detector performance and first

Giulio Ruffini, Marco Caparrini, Leonardo Ruffini

A portion of 20 minutes of the GPS signals collected during the Bridge 2 experimental campaign, performed by ESA, have been processed. An innovative algorithm called Parfait, developed by Starlab and implemented within Starlab&#39;s GNSS-R Software package STARLIGHT (STARLab Interferometric Gnss Toolkit), has been successfully used with this set of data. A c

S. Batsouli, S. Kelly, M. Gyulassy, J. L. Nagle

Recent PHENIX Au+Au -> e- + X data from open charm decay are shown to be consistent with two extreme opposite dynamical scenarios of ultra-relativistic nuclear reactions. Perturbative QCD without final state interactions was previously shown to be consistent with the data. However, we show that the data are also consistent with zero mean free path hydrodynam

N. E. Ligterink

We construct the $Δ$ resonance as a superposition of a bare $Δ$ state and the $πN$ continuum. It is parametrized by three coupling constants for local $πN Δ$ and $ππN N$ couplings and the $Δ$ mass. The latter incorporates the mass renormalization due to the $πN Δ$ interaction, while the results depend only weakly, if at all, on its wave-function renormalizat

L. P. Kaptari, B. Kampfer, S. S. Semikh

The reaction p d -> d phi p_{sp} is studied within the Bethe-Salpeter formalism. Under special kinematical conditions (slow backward spectator proton p_{sp} and fast forward deuteron) relevant for forthcoming experiments at COSY, the cross section and a set of polarization observables factorize in the contribution of the pure subprocess p n -> d phi and a co

I. Bednarek, M. Keska, R. Manka

In this paper an equation of state of neutron star matter which includes strange baryons in the framework of Zimanyi and Moszkowski (ZM) model has been obtained. We concentrate on the effects of the isospin dependence of the equation of state constructing for the appropriate choices of parameters the hyperons star model. Numerous neutron star models show tha

L. P. Kaptari, B. Kampfer, S. S. Semikh, S. M. Dorkin

Recent data on the reaction pD -> (pp) n with a fast forward pp pair with very small excitation energy is analyzed within a covariant approach based on the Bethe-Salpeter formalism. It is demonstrated that the minimum non-relativistic amplitude is completely masked by relativistic effects, such as Lorentz boost and the negative-energy P components in the 1S_

Lj. Simic, J. Milosevic

Anisotropic flow of protons and negative pions in 4.2A GeV/c C+Ta collisions is studied using the Fourier analysis of azimuthal distributions. The protons exhibit pronounced directed flow. Directed flow of pions is positive in the entire rapidity interval and indicates that the pions are preferentially emitted in the reaction plane from the target to the pro

Panayotis G. Kevrekidis, Niurka R. Quintero

The scope of this work is to propose a method for testing the integrability of a model partial differential (PDE) and/or differential difference equation (DDE). For monoparametric families of PDE/DDE&#39;s, that are known to possess isolated integrable points, we find that very special features occur in the continuous (``phonon&#39;&#39;) spectrum at these `

V. V. Fernández, A. M. Moya, W. A. Rodrigues

In this paper we introduce the concept of metric Clifford algebra $\mathcal{C\ell}(V,g)$ for a $n$-dimensional real vector space $V$ endowed with a metric extensor $g$ whose signature is $(p,q)$, with $p+q=n$. The metric Clifford product on $\mathcal{C\ell}(V,g)$ appears as a well-defined \emph{deformation}(induced by $g$) of an euclidean Clifford product on

A. J. Macfarlane, Hendryk Pfeiffer

The uniformity of the decomposition law, for a family F of Lie algebras which includes the exceptional Lie algebras, of the tensor powers ad^n of their adjoint representations ad is now well-known. This paper uses it to embark on the development of a unified tensor calculus for the exceptional Lie algebras. It deals explicitly with all the tensors that arise

Virginia V. Fernández, Antonio M. Moya, Waldyr A. Rodrigues

In this paper we introduce a class of mathematical objects called \emph{extensors} and develop some aspects of their theory with considerable detail. We give special names to several particular but important cases of extensors. The \emph{extension,} \emph{adjoint} and \emph{generalization} operators are introduced and their properties studied. For the so-cal

Sergi Elizalde

In this paper we prove that among the permutations of length n with i fixed points and j excedances, the number of 321-avoiding ones equals the number of 132-avoiding ones, for all given i,j<=n. We use a new technique involving diagonals of non-rational generating functions. This theorem generalizes a recent result of Robertson, Saracino and Zeilberger, for

Aaron D. Lauda

A 2-group is a `categorified&#39; version of a group, in which the underlying set G has been replaced by a category and the multiplication map m: G x G -> G has been replaced by a functor. A number of precise definitions of this notion have already been explored, but a full treatment of their relationships is difficult to extract from the literature. Here we

T. Constantinescu, A. Gheondea

In previous works we analysed conditions for linearization of hermitian kernels. The conditions on the kernel turned out to be of a type considered previously by L. Schwartz in the related matter of characterizing the real space generated by positive definite kernels. The aim of this note is to find more concrete expressions of the Schwartz type conditions:

Uwe Nagel

A locally free resolution of a subscheme is by definition an exact sequence consisting of locally free sheaves (except the ideal sheaf) which has uniqueness properties like a free resolution. The purpose of this paper is to characterize certain locally Cohen-Macaulay subschemes by means of locally free resolutions. First we achieve this for arithmetically Bu

J. Cortes, S. Martinez, T. Karatas, F. Bullo

This paper presents control and coordination algorithms for groups of vehicles. The focus is on autonomous vehicle networks performing distributed sensing tasks where each vehicle plays the role of a mobile tunable sensor. The paper proposes gradient descent algorithms for a class of utility functions which encode optimal coverage and sensing policies. The r

Benoit Arbour, Damien Roy

We establish a criterion for a complex number to be algebraic over Q of degree at most two. It requires that, for any sufficiently large real number X, there exists a non-zero polynomial with integral coefficients, of degree at most two and height at most X, whose absolute value at that complex number is at most (1/4)X^{-(3+sqrt{5})/2}. We show that the expo

Najmuddin Fakhruddin

In this note we discuss some arithmetic and geometric questions concerning self maps of projective algebraic varieties.

Hechun Zhang

The purpose of this note is to give explicit criteria to determine whether a real generalized Cartan matrix is of finite type, affine type or of hyperbolic type by considering the principal minors and the inverse of the matrix. In particular, it will be shown that a real generalized Cartan matrix is of finite type if and only if it is invertible and the inve

Jean-Louis Loday, Michael R. Stein

We introduce the notion of a braid group parametrized by a ring, which is defined by generators and relations and based on the geometric idea of painted braids. We show that the parametrized braid group is isomorphic to the semi-direct product of the Steinberg group (of the ring) with the classical braid group. The technical heart of the proof is the Pure Br

Yuri M. Berezansky, Eugene Lytvynov, Dmytro A. Mierzejewski

We derive an explicit formula for the Jacobi field that is acting in an extended Fock space and corresponds to an ($\R$-valued) Lévy process on a Riemannian manifold. The support of the measure of jumps in the Lévy--Khintchine representation for the Lévy process is supposed to have an infinite number of points. We characterize the gamma, Pascal, and Meixner

J. Denef, F. Loeser

We illustrate the principle: rational generating series occuring in arithmetic geometry are motivic in nature.

X. Bardina, D. Marquez, C. Rovira, S. Tindel

This paper is devoted to a detailed study of a p-spins interaction model with external field, including some sharp bounds on the speed of self averaging of the overlap as well as a central limit theorem for its fluctuations, the thermodynamical limit for the free energy and the definition of an Almeida-Thouless type line. Those results show that the external

Najmuddin Fakhruddin

We prove that if f is a self-map of an algebraic variety over a field K, then under certain conditions on X, f and K the set of possible periods of K-valued periodic points of f is finite.

Matthew Baker

Let K be a number field and let E/K be an elliptic curve. If E has complex multiplication, we show that there is a positive lower bound for the canonical height of non-torsion points on E defined over the maximal abelian extension K^ab of K. This is analogous to results of Amoroso-Dvornicich and Amoroso-Zannier for the multiplicative group. We also show that

David Chataur, Jean-Claude Thomas

We construct for any algebra over an operad an Hochschild chain complex. In the case of the singular cochain complex of a topological space, considered as a commutative algebra up to homotopy, we show that this complex computes the singular cohomology of the free loop space over this topological space.

R. P. Thomas, S. -T. Yau

We make a conjecture about mean curvature flow of Lagrangian submanifolds of Calabi-Yau manifolds, expanding on \cite{Th}. We give new results about the stability condition, and propose a Jordan-Hölder-type decomposition of (special) Lagrangians. The main results are the uniqueness of special Lagrangians in hamiltonian deformation classes of Lagrangians, und

Marcos Jardim, Antony Maciocia

We study U(r) instantons on elliptic surfaces with a section and show that they are in one-one correspondence with spectral data consisting of a curve in the dual elliptic surface and a line bundle on that curve. We use relative Fourier-Mukai transforms to analyse their properties and, in the case of the K3 and abelian surfaces, we show that the moduli space

Dmitri Diakonov

Quantum Yang-Mills theory and the Wilson loop can be rewritten identically in terms of local gauge-invariant variables being directly related to the metric of the dual space. In this formulation, one reveals a hidden high local symmetry of the Yang-Mills theory, which mixes up fields with spins up to J=N for the SU(N) gauge group. In the simplest case of the