February 1995 arXiv papers — page 3

Grigorii B. Pivovarov

We derive a relation between four-fermion QED Green functions of different covariant gauges which defines the gauge dependence completely. We use the derived gauge dependence to check the gauge invariance of atom-like bound state calculations. We find that the existing QED procedure does not provide gauge invariant binding energies. A way to a corrected gaug

H. H. Shih, Y. C. Lin

We derive the vertices of five-meson and seven-meson anomaly processes from the four dimensional expansion form of Wess-Zumino term. Using these vertices we calculate the amplitude, both the finite part and divergent part, of {$K^+ K^- \rightarrow π^0 π^+ π^-$} to one loop and renormalize the lagrangian. The divergent part agrees with the result derived from

Th. Pruschke, M. Jarrell, J. K. Freericks

A systematic study of optical and transport properties of the Hubbard model, based on Metzner and Vollhardt's dynamical mean-field approximation, is reviewed. This model shows interesting anomalous properties that are, in our opinion, ubiquitous to single-band strongly correlated systems (for all spatial dimensions greater than one), and also compare qua

Y. Kodama, K. T-R McLaughlin

We give an explicit formula for the solution to the initial value problem of the full symmetric Toda hierarchy. The formula is obtained by the orthogonalization procedure of Szegö, and is also interpreted as a consequence of the QR factorization method of Symes \cite{symes}. The sorting property of the dynamics is also proved for the case of a generic symmet

V. B. Belyaev, M. Decker, H. Fiedeldey, S. A. Rakityansky

In this report we will discuss properties of and models for nuclear transitions in muonic molecules formed via collisions of muonic atoms of hydrogen isotopes with light nuclei like $L\!i$ and $B\!e$. Their importance for nuclear astrophysics and nuclear physics at super low energies is emphasized.

Gordon Baym, B. Blättel, L. L. Frankfurt, H. Heiselberg

Nucleon correlations in the target and projectile nuclei are shown to reduce significantly the fluctuations in multiple nucleon-nucleon collisions, total multiplicity and transverse energy in relativistic heavy-ion collisions, in particular for heavy projectile and target. The interplay between cross-section fluctuations, from color transparency and opacity,

Bulbul Chakraborty

Recent experiments in metallic solid solutions have revealed interesting correlations between static pair-displacements and the ordering behavior of these alloys. This paper discusses a simple theoretical model which successfully explains these observations and which provides a natural framework for analyzing experimental measurements of pair-displacements a

J. Brian Conrey, David W. Farmer

Associated to a newform $f(z)$ is a Dirichlet series $L_f(s)$ with functional equation and Euler product. Hecke showed that if the Dirichlet series $F(s)$ has a functional equation of the appropriate form, then $F(s)=L_f(s)$ for some holomorphic newform $f(z)$ on $Γ(1)$. Weil extended this result to $Γ_0(N)$ under an assumption on the twists of $F(s)$ by Dir

M. J. Martins

We have applied the analytical Bethe ansatz approach in order to solve the $Osp(1|2n)$ invariant magnet. By using the Bethe ansatz equations we have calculated the ground state energy and the low-lying dispersion relation. The finite size properties indicate that the model has a central charge $c=n$.

Viktor Dotsenko, Vladimir Dotsenko, Marco Picco, Pierre Pujol

We find a new solution of the renormalization group for the Potts model with ferromagnetic random valued coupling constants. The solution exhibits universality and broken replica symmetry. It is argued that the model reaches this universality class if the replica symmetry is broken initially. Otherwise the model stays with the replica symmetric renormalizati

M. Gasperini, M. Giovannini, K. A. Meissner, G. Veneziano

We discuss the temporal variation of the equation of state of a classical string network, evolving in a background in which the Hubble radius 1/H shrinks to a minimum and then re-expands to infinity. We also present a method to look for self-consistent non-vacuum string backgrounds, correponding to the simultaneous solution of the gravi-dilaton backgrounds e

M. Knecht, R. Pasquier, J. Y. Pasquier

A model for planar phenomena introduced by Jackiw and Pi and described by a Lagrangian including a Chern-Simons term is considered. The associated equations of motion, among which a 2+1 gauged nonlinear Schrödinger equation, are rewritten into a gauge independent form involving the modulus of the matter field. Application of a Painlevé analysis, as adapted t

T. Fujiwara, Y. Igarashi, R. Kuriki, T. Tabei

Two-dimensional supergravity theory is quantized as an anomalous gauge theory. In the Batalin-Fradkin (BF) formalism, the anomaly-canceling super-Liouville fields are introduced to identify the original second-class constrained system with a gauge-fixed version of a first-class system. The BFV-BRST quantization applies to formulate the theory in the most gen

Shaouly Bar-Shalom, David Atwood, Gad Eilam, Amarjit Soni

CP violation effects in $e^+ e^- \to t\bar tg$ are examined. CP-odd, $T_n$-odd and $T_n$-even observables can both be used to extract information on the real and imaginary parts of Feynman amplitudes. Two Higgs doublet model with CP violating phase from neutral Higgs exchange is used to estimate possible effects.

S. Gavin, R. Kauffman, S. Gupta, P. V. Ruuskanen

We compute cross sections for the Drell-Yan process in N--N collisions at next-to-leading order in $α_s$. The mass, rapidity, transverse momentum, and angular dependence of these cross sections are presented. An estimate of higher order corrections is obtained from next-to-next-to-leading order calculation of the mass distribution. We compare the results wit

Claudio Rebbi, Robert Singleton,

We illustrate the use of computational methods for the study of baryon non-conservation in high energy electroweak processes.

P. De Felice, G. Nardulli, G. Pasquariello

We study the possibility to employ neural networks to simulate jet clustering procedures in high energy hadron-hadron collisions. We concentrate our analysis on the Fermilab Tevatron energy and on the $k_\bot$ algorithm. We consider both supervised multilayer feed-forward network trained by the backpropagation algorithm and unsupervised learning, where the n

A. Pich

An introduction to the basic ideas and methods of Chiral Perturbation Theory is presented. Several phenomenological applications of the effective Lagrangian technique to strong, electromagnetic and weak interactions are discussed.

Johan Bijnens, Joaquim Prades

We calculate the $B_K$ parameter within the framework of the $1/N_c$ expansion. We essentially use the technique presented by Bardeen, Buras and Gérard but calculate an off-shell Green function in order to disentangle different contributions. We study this Green function in pure Chiral Perturbation Theory (CHPT) first and afterwards in the $1/N_c$ expansion

Hanbin Pang, H. Akhlaghpour, M. Jarrell

A numerical approach to ground-state dynamical correlation functions from Density Matrix Renormalization Group (DMRG) is developed. Using sum rules, moments of a dynamic correlation function can be calculated with DMRG, and with the moments the dynamic correlation function can be obtained by the maximum entropy method. We apply this method to one-dimensional

Holger Frahm, Claus R"odenbeck

We show that the solutions of the Yang--Baxter equation invariant under the action of the Yangian $Y(sl_2)$ lead to inhomogenous vertex models. Starting from a four dimensional representation of $Y(sl_2)$ we obtain an integrable family of coupled Heisenberg spin-$1\over2$ chains. Some thermodynamical properties of this model are studied by means of the algeb

Peter Kopietz, Kurt Schoenhammer

We bosonize the long-wavelength excitations of interacting fermions in arbitrary dimension by directly applying a suitable Hubbard-Stratonowich transformation to the Grassmannian generating functional of the fermionic correlation functions. With this technique we derive a surprisingly simple expression for the single-particle Greens-function, which is valid

Mustansir Barma, R. S. Bhalerao

The systematics of the size dependence of the resonant response of small metal particles and nuclei to incident electromagnetic radiation is studied. The known radius$^{-1}$ variation of the full width at half maximum (FWHM) in matrix-embedded metal particles is qualitatively accounted for by a quantum calculation of the response within a simple model. In fr

Ted Pedersen, Weidong Chen

This paper describes a method to automatically acquire the syntactic and semantic classifications of unknown words. Our method reduces the search space of the lexical acquisition problem by utilizing both the left and the right context of the unknown word. Link Grammar provides a convenient framework in which to implement our method.

Guido Boffetta, Giovanni Paladin, Angelo Vulpiani

We discuss the predictability of a conservative system that drives a chaotic system with positive maximum Lyapunov exponent $λ_0$, such as the erratic motion of an asteroid in the gravitational field of two bodies of much larger mass. We consider the case where in absence of feedback (restricted model), the driving system is regular and completely predictabl

D. A. White, A. C. Fabian

We analyse the X-ray surface brightness profiles of 19 moderately distant and luminous clusters of galaxies observed with the \EINOBS. Our aim is to determine cluster gas masses out to radii between 1 and $3\Mpc$, and to confirm the apparent conflict, if $Ω_0=1$, between the current calculations of the mean baryon fraction of the Universe expected from stand

Massimo Persic, Paolo Salucci

We present the rotation curves (RCs) of 967 spiral galaxies, obtained by folding and deprojecting the raw optical data by Mathewson et al. (1992). Out of these, we have identified 80 excellent RCs and 820 fair RCs. The 80 excellent RCs are smooth, symmetric, have negligible rms internal error, extend to at least the optical radius, and have high and homogene

William Andersen, Walter Wilcox

Using lattice QCD on a $16^{3}\times 24$ lattice at $β=6.0$, we examine the elastic limit of charge overlap functions in the quenched approximation for the pion and rho meson; results are compared to previous direct current insertion calculations. A good signal is seen for the pion, but the electric and magnetic rho meson results are considerably noisier. We

S. Zaleski, Jie Li, S. Succi

The large deformations and break up of circular 2D liquid patches in a high Reynolds number (Re=1000) gas flow are investigated numerically. The 2D, plane flow Navier--Stokes equations are directly solved with explicit tracking of the interface between the two phases and a new algorithm for surface tension. The numerical method is able to pursue the simulati

S. Schreckenberg

The basic ingredients of the `consistent histories' approach to a generalized quantum theory are `histories'and decoherence functionals. The main aim of this program is to find and to study the behaviour of consistent sets associated with a particular decoherence functional $d$. In its recent formulation by Isham it is natural to identify the space $

F. Cardarelli, I. L. Grach, I. M. Narodetskii, G. Salme'

The electromagnetic form factors of the $ρ$ meson are evaluated adopting a relativistic constituent quark model based on the light-front formalism, and using a meson wave function with the high-momentum tail generated by the one-gluon-exchange interaction. The breakdown of the rotational covariance for the one-body component of the current operator is invest

A. M. Tsvelik

We study the Toulouse limit of the multi-channel Kondo model defined as the limit of maximal anisotropy which can be achieved without changing the infrared behaviour of the model. It is shown that when the number of channels exceeds 2, the interactions do not vanish and the Toulouse limit remains a non-trivial field theory. Considerable simplifications take

Georg Raffelt

If axions exist they are efficiently produced in the hot and dense interior of stars, providing a novel energy-loss mechanism. In order to avoid a conflict with the observed properties of stars, one can derive a lower limit on the Peccei-Quinn scale (an upper limit on the axion mass). In the early universe, axions are produced by the ``misalignment mechanism

Uwe Reyle

The paper adresses the problem of reasoning with ambiguities. Semantic representations are presented that leave scope relations between quantifiers and/or other operators unspecified. Truth conditions are provided for these representations and different consequence relations are judged on the basis of intuitive correctness. Finally inference patterns are pre

Eugene Kogan, Moshe Kaveh

Statistical properties of coherent radiation propagating in a quasi - 1D random media is studied in the framework of random matrix theory. Distribution functions for the total transmission coefficient and the angular transmission coefficient are obtained.

Andrzej Czarnecki, Marek Jezabek

We summarize recent results on QCD corrections to various observables in semileptonic $b$ quark decays. For massless leptons in the final state we present effects of such corrections on triple differential distribution of leptons which are important in studies of polarized $b$ quark decays. Analogous formulas for distributions of neutrinos are applicable in

Kong Joo Lee, Cheol Jung Kweon, Jungyun Seo, Gil Chang Kim

In this paper, we propose a robust parser which can parse extragrammatical sentences. This parser can recover them using only syntactic information. It can be easily modified and extended because it utilize only syntactic information.

B. Huttner, N. Imoto, N. Gisin, T. Mor

The safety of a quantum key distribution system relies on the fact that any eavesdropping attempt on the quantum channel creates errors in the transmission. For a given error rate, the amount of information that may have leaked to the eavesdropper depends on both the particular system and the eavesdropping strategy. In this work, we discuss quantum cryptogra

B. Crowell, P. Chowdhury, D. J. Blumenthal, S. J. Freeman

An isomer, with t1/2 = 35 +- 10 ns and J, Kpi = 14, 14+, has been observed in the nucleus 176W using the reaction 150Nd(30Si,4n) at a beam energy of 133 MeV. The isomer exhibits an unusual pattern of decay in which the _majority_ of the flux proceeds directly to states with <K>=0, bypassing available levels of intermediate K. This severe breakdown of normal

Valentin Ferenczi

A space $X$ is said to be hereditarily indecomposable if no two (infinite dimensional) subspaces of $X$ are in a direct sum. In this paper, we show that if $X$ is a complex hereditarily indecomposable Banach space, then every operator from a subspace $Y$ of $X$ to $X$ is of the form $λI + S$, where $I$ is the inclusion map and $S$ is strictly singular.

Thomas Curtright, Cosmas Zachos

A generating functional $F$ is found for a canonical nonabelian dual transformation which maps the supersymmetric chiral O(4) $σ$-model to an equivalent supersymmetric extension of the dual $σ$-model. This $F$ produces a mapping between the classical phase spaces of the two theories in which the bosonic (coordinate) fields transform nonlocally, the fermions

Marcus Hutter

After a general discussion on the choice of gauge, we compare the quark propagator in the background of one instanton in regular and singular gauge with a gauge invariant propagator obtained by inserting a path-ordered gluon exponential. Using a gauge motivated by this analysis, we were able to obtain a finite result for the quark condensate without introduc

Miguel Angel Sanchis-Lozano

We explore the application and usefulness of the heavy quark symmetry to describe the weak decays of hadrons (mesons and baryons) containing two heavy quarks. Firstly, we address the internal dynamics of a heavy-heavy bound system with the help of estimates based on potential models, showing an approximate spin symmetry in the preasymptotic quark mass region

ZEUS Collaboration

Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xg, the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and in th

L. Berezansky, E. Braverman

The paper is concerned with stabilization of a scalar delay differention equation $$ {\dot x}(t) - \sum_{k=1}^m A_k(t)x[h_k(t)] = 0,~t\geq 0,~ x(ξ)=φ(ξ), ξ<0, $$ by introducing impulses in certain moments of time $$ x(τ_j) = B_j x(τ_j -0), ~j=1,2, \dots ~. $$ Explicit stability results are presented both for the equation with positive coefficients and for th

L. Y. Gorelik, V. S. Shumeiko, R. I. Shekhter, G. Wendin

We consider the supercurrent flow through gated mesoscopic semiconductor hetrostructures in which a two-dimensional normal constriction is confined between superconducting electrodes. We show that for these structures the Josephson current, carried by quantized electron modes, can be strongly affected by an electromagnetic field. Photon-assisted Landau-Zener

A. Nazarenko, K. J. E. Vos, S. Haas, E. Dagotto

Recent angle resolved photoemission (ARPES) results for the insulating cuprate ${\rm Sr_2 Cu O_2 Cl_2}$ have provided the first experimental data which can be directly compared to the (theoretically) well--studied problem of a single hole propagating in an antiferromagnet. The ARPES results reported a small bandwidth, providing evidence for the existence of

Natan Andrei, Michael R. Douglas, Andrés Jerez

We study models of chiral interacting fermions by means of conformal and Bethe-Ansatz techniques, and determine their thermodynamic properties and asymptotic correlation functions. We identify a class of fixed points characterizing the infrared behavior of the models. They display {\it chirally stabilized} non Fermi-Liquid behavior characterized by universal

W. Lehle, A. Schmid

In this paper, we study the physics of mesoscopic systems with noninteracting, but fixed number of electrons. From a technical point of view, this means a discussion of the differences between the canonical and the grand canonical ensemble (fixed versus fluctuating number of particles). Such a discussion is not trivial since the grand canonical ensemble is t

Frank Keller

This paper investigates the syntax of extraposition in the HPSG framework. We present English and German data (partly taken from corpora), and provide an analysis using lexical rules and a nonlocal dependency. The condition for binding this dependency is formulated relative to the antecedent of the extraposed phrase, which entails that no fixed site for extr

Anette Frank, Uwe Reyle

The paper presents a constraint based semantic formalism for HPSG. The syntax-semantics interface directly implements syntactic conditions on quantifier scoping and distributivity. The construction of semantic representations is guided by general principles governing the interaction between syntax and semantics. Each of these principles acts as a constraint

P. Meszaros

Whatever the ultimate energy source of gamma-ray bursts turns out to be, the resulting sequence of physical events is likely to lead to a fairly generic, almost unavoidable scenario: a relativistic fireball that dissipates its energy after it has become optically thin. This is expected both for cosmological and halo distances. Here we explore the observation

F. Bernardeau

For Gaussian initial conditions the perturbation theory predicts a very specific hierarchy for the projected matter $p$-point correlation functions. In the small angle approximation and assuming a power-law spectrum I derive the exact expressions of the coefficients $s_p$ relating the averaged $p$-order angular correlation function, $\omb_p$ to the second on

Alejandro Gonzalez S., Oscar Martinez

The morphological distribution of primordial density peaks is assessed. Previous determinations, those of Peacock & Heavens (1985) and those of Bardeen et al (1986) have contradictory concluded that there exist a tendency towards prolate or towards oblate shapes, respectively. By using two methods, the Hessian and the inertia tensor momenta we have performed

Tyler J. Jarvis

This article treats compactifications of the space of generalized spin curves. Generalized spin curves, or $r$-spin curves, are pairs $(X,L)$ with $X$ a smooth curve and $L$ a line bundle whose r-th tensor power is isomorphic to the canonical bundle of $X.$ These are a natural generalization of $2$-spin curves (algebraic curves with a theta-characteristic),

Sergey S. Kurennoy, Yong Ho Chin

The longitudinal and transverse coupling impedances produced by the long slots in the Low Energy Ring of KEK B-factory are calculated. The power dissipated inside the vacuum chamber due to the fields scattered by the slots is evaluated using results for the real part of the coupling impedance. Estimates are made for the power flow through the slots to the pu

S. Majid

The braided approach to q-deformation (due to the author and collaborators) gives natural algebras $R_{21}u_1Ru_2=u_2R_{21}u_1R$ and $R_{21}x_1x_2=x_2x_1R$ for q-Minkowski and q-Euclidean spaces respectively. These algebras are covariant under a corresponding background `rotation&#39; quantum group. Semidirect product by this according to the bosonisation pr

C. Klimcik, P. Severa

The standard notion of the non-Abelian duality in string theory is generalized to the class of $\si$-models admitting `non-commutative conserved charges&#39;. Such $\si$-models can be associated with every Lie bialgebra $(\cg ,\cgt)$ and they possess an isometry group iff the commutant $[\cgt,\cgt]$ is not equal to $\cgt$. Within the enlarged class of the ba

P. Pyatov, P. Saponov

General algebraic properties of the algebras of vector fields over quantum linear groups $GL_q(N)$ and $SL_q(N)$ are studied. These quantum algebras appears to be quite similar to the classical matrix algebra. In particular, quantum analogues of the characteristic polynomial and characteristic identity are obtained for them. The $q$-analogues of the Newton r

A. P. J. Jansen

We present results of a Monte Carlo study of temperature-programmed desorption in a model system with attractive lateral interactions. It is shown that even for weak interactions there are large shifts of the peak maximum temperatures with initial coverage. The system has a transition temperature below which the desorption has a negative order. An analytical

Myriam Mondragon, Lukas Nellen, Michael G. Schmidt, Christian Schubert

We construct the world-line action for a Dirac particle coupled to a classical scalar or pseudo-scalar background field. This action can be used to compute loop diagrams and the effective action in the Yukawa model using the world-line path-integral formalism for spinning particles.

A. P. Martynenko, V. A. Saleev

Based on photon structure function formalism we have calculated $B_c(B_c^{*})$ meson production cross section in $\gamma\gamma$ collisions via partonic subprocess $c\gamma\to B_c(B_c^{*}) b$. It was shown that this approach gives the same results for $B_c^*(B_c)$ meson cross sections as the direct leading order QCD calculation of the subprocess $\gamma\gamma

Dae Sung Hwang, C. S. Kim, Wuk Namgung

The Gaussian width of Fermi momentum, $p_{_F}$, is the most important parameter of the ACCMM model, and its value is essential in the determination of $|V_{ub}/V_{cb}|$ because the experimental analysis is allowed only at the end-point region of inclusive semileptonic $B$-decay spectrum. We extract the value of $|V_{ub}/V_{cb}|$ as a function of $p_{_F}$. We

Victor Ginzburg, Mikhail Kapranov, Eric Vasserot

This note is an attempt to extend &#34;Geometric Langlands Conjecture&#34; from algebraic curves to algebraic surfaces. We introduce certain Hecke-type operators on vector bundles on an algebraic surface. The crucial observation is that the algebra generated by the Hecke operators turns out to be a homomorphic image of the {\it quantum toroidal algebra}. The

Dimitri Polyakov

We explore geometrical properties of fermionic vertex operators for a NSR superstring in order to establish connection between worldsheet and target space supersymmetries. The mechanism of picture-changing is obtained as a result of imposing certain constraints on a world-sheet gauge group of the NSR theory. It is found that picture-changing operators of var

Yang Chen, Kasper J. Eriksen, Craig A. Tracy

Using thermodynamic arguments we find that the probability that there are no eigenvalues in the interval (-s,\infty) in the double scaling limit of Hermitean matrix models is O(exp(-s^{2m+1})) as s\to+\infty.Here m=1,2,3.. determine the m^{th} multi-critical point of the level density:σ(x)\sim b[1-(x/b)^2]^{m-1/2} and b^2\sim N.Furthermore,the size of the tr

S. A. Frolov

Hamiltonian lattice gauge models based on the assignment of the Heisenberg double of a Lie group to each link of the lattice are constructed in arbitrary space-time dimensions. It is shown that the corresponding generalization of the gauge-invariant Wilson line observables requires to attach to each vertex of the line a vertex operator which goes to the unit

Mirjam Cvetic, Donam Youm

We point out that in heterotic string theory compactified on a 6-torus, after a consistent truncation of the 10-d gauge fields and the antisymmetric tensor fields, 4-dimensional black holes of Kaluza-Klein theory on a 6-torus constitute a subset of solutions.

K. Goulianos

While the main features of elastic, diffractive and total cross sections are described well by Regge theory, the measured rise of the proton-(anti)proton single diffraction dissociation cross section with energy is considerably smaller than the theoretical prediction based on factorization and a constant triple-pomeron coupling. The observed energy dependenc

Oscar F. Hernandez

After a short introduction to the SM picture of CP violation, we discuss recent work on how to use SU(3) flavor symmetry, along with some dynamical approximations, to extract the CKM weak phases and the strong rescattering phases from experimental measurements alone. This suprising wealth of information depends on our two strongest assumptions: SU(3) invaria

O. K. Kalashnikov

The calculations in the temporal axial gauge (TAG) are revised and a new prescription is introduced to avoid the well-known TAG-singularity. With this prescription we use the TAG-formalism to calculate the one-loop dispersion equation for the longitudinal plasma oscillations in the high temperature limit and find the complete selfconsistency of TAG for pragm

Jyoti Agrawal, Paul H. Frampton, James T. Liu

The 3-3-1 model, based on the gauge group $SU(3)_c\times SU(3)_L\times U(1)_X$, makes a natural prediction of three generations based on anomaly cancellation. Since this is accomplished by incorporating the third family of quarks differently from the other two, it leads to potentially large flavor changing neutral currents. A sensitive place to look for such

G. Martinelli, C. T. Sachrajda

We propose a non-perturbative method for defining the higher dimensional operators which appear in the Heavy Quark Effective Theory (HQET), such that their matrix elements are free of renormalon singularities, and diverge at most logarithmically with the ultra-violet cut-off. Matrix elements of these operators can be computed numerically in lattice simulatio

Arnon Dar

Astrophysics and cosmology can be used to test the standard model of particle physics under conditions and over distance and time scales not accessible to laboratory experiments. Most of the astrophysical observations are in good agreement with the standard model. In particular, primordial nucleosynthesis, supernova explosions, stellar evolution and cosmic b

Rafia Ali, Pervez Hoodbhoy

An effective, low-energy, field theory of s-wave quarkonia, constituent heavy quarks, and gluons is constructed which is manifestly gauge invariant. The interaction Lagrangian has the form of a twist expansion, as typically encountered in hard processes, and involves derivatives of arbitrary order. The parameters in the interaction are related with the non-r

Muhammad Nzar, Pervez Hoodbhoy

A simple quark-diquark model for nucleon and $Λ$ structure is used to calculate leading twist light-cone fragmentation functions for a quark to inclusively decay into P or $Λ$. The parameters of the model are determined by fitting to the known deep-inelastic structure functions of the nucleon. When evolved from the initial to the final $Q^2$ scale, the calcu

A. L. Kataev, V. V. Starshenko

We present the attempt to study the problem of the estimates of higher-order perturbative corrections to physical quantities in the Euclidean region. Our considerations are based on the application of the scheme-invariant methods, namely the principle of minimal sensitivity and the effective charges approach. We emphasize, that in order to obtain the concret

H. U. Baranger, P. A. Mello

We propose an information-theoretic statistical model to describe the universal features of those chaotic scattering processes characterized by a prompt and an equilibrated component. The model, introduced in the past in nuclear physics, incorporates the average value of the scattering matrix to describe the prompt processes, and satisfies the requirements o

Andrew A. de Laix, Robert J. Scherrer, Robert K. Schaefer

We consider the growth of density perturbations in the presence of self--interacting dark matter, SIDM, proposed by Carlson, Machacek and Hall (1992). We determine the range of values for the coupling constant $λ$ and the particle mass $m^\prime$, for which the power spectrum lies in the ``allowed&#34; range based on constraints from the IRAS galaxy survey a

Slavek M. Rucinski

77 W~UMa-type systems to $I=18$ mag in one of the 21 fields of OGLE have been assessed in terms of utility for extraction of astrophysical information from time-independent data such as colors, periods, maximum magnitudes, and variability amplitudes in the final global OGLE catalog which will contain $>1000$ contact binaries. A subset of systems with absolut

Karl Mannheim

Proton acceleration in nearby blazars can be diagnosed measuring their intense TeV $γ$-ray emission. Flux predictions for 1101+384 (Mrk421) and 1219+285 (ON231), both strong EGRET sources (0.1-10 GeV), are obtained from model spectra of unsaturated synchrotron pair cascades fitted to publicly available multifrequency data. An experimental effort to confirm t

Roman Bezrukavnikov

We show how the Frobenius splitting method of Mehta-Ramanathan implies the Koszul property of projective coordinate rings of Schubert varieties.

Jose M. Gracia-Bondia

Massive neutrinos can be accommodated into the noncommutative geometry reinterpretation of the Standard Model. The constrained Standard Model Lagrangian is computed anew under the assumption of nonzero neutrino masses. This gives the ``prediction&#34; of a mass for the Higgs particle somewhat higher than in the vanishing neutrino mass case.

Martin Sieber, Harel Primack, Uzy Smilansky, Iddo Ussishkin

The semiclassical theory for billiards with mixed boundary conditions is developed and explicit expressions for the smooth and the oscillatory parts of the spectral density are derived. The parametric dependence of the spectrum on the boundary condition is shown to be a very useful diagnostic tool in the semiclassical analysis of the spectrum of billiards. I

Ernest Baver, Doron Gepner

We present fermionic sum representation for the general Virasoro character of the unitary minimal superconformal series ($N=1$). Example of the corresponding ``finitizated&#34; identities relating corner transfer matrix polynomials with fermionic companions is considered. These identities in the thermodynamic limit lead to the generalized Rogers-Ramanujan id

Djordje Minic

Analogs of ordinary Gaussian coherent states on bosonic Fock spaces are constructed for the case of free Fock spaces, which appear to be natural mathematical structures suitable for description of large N matrix models.

W. Janke, H. Kleinert

As an application of a recently developed variational perturbation theory we find the first 22 terms of the convergent strong-coupling series expansion for the ground state energy of the quartic anharmonic oscillator.

W. Janke, H. Kleinert

We prove a powerful scaling property for the extremality condition in the recently developed variational perturbation theory which converts divergent perturbation expansions into exponentially fast convergent ones. The proof is given for the energy eigenvalues of an anharmonic oscillator with an arbitrary $x^p$-potential. The scaling property greatly increas

Douglas Singleton

By casting the Yang-Mills-Higgs equations of an SU(2) theory in the form of the Ernst equations of general relativity, it is shown how the known exact solutions of general relativity can be used to give similiar solutions for Yang-Mills theory. Thus all the known exact solutions of general relativity with axial symmetry (e.g. the Kerr metric, the Tomimatsu-S

Michael R. Geller, Giovanni Vignale

We present a general theory for the equilibrium current distribution in an interacting two-dimensional electron gas subjected to a perpendicular magnetic field, and confined by a potential that varies slowly on the scale of the magnetic length. The distribution is found to consist of strips or channels of current, which alternate in direction, and which have

Andrew S. Fruchter, Jay Bookbinder, Charles D. Bailyn

We have obtained images of the eclipsing pulsar binary PSR~B1957+20 using the Planetary Camera of the Hubble Space Telescope. The high spatial resolution of this instrument has allowed us to separate the pulsar system from a nearby background star which has confounded ground-based observations of this system near optical minimum. Our images limit the tempera

Jane C. Charlton

The classic question regarding Lyman-alpha forest clouds is whether they are confined by the pressure of a hot, diffuse surrounding medium, or by the gravity of dark matter mini-halos. This paper reviews these basic models for forest clouds, considering spherical and slab geometries. At high redshift, the clouds are still likely to be in the process of forma

J. E. Hetrick, Y. Hosotani, S. Iso

QED with N species of massive fermions on a circle of circumference L is analyzed by bosonization. The problem is reduced to the quantum mechanics of the 2N fermionic and one gauge field zero modes on the circle, with nontrivial interactions induced by the chiral anomaly and fermions masses. The solution is given for N=2 and fermion masses (m) much smaller t

Susumu Ariki, Tatsuhiro Nakajima, Hiro-Fumi Yamada

The basic representation of $\A$ is studied. The weight vectors are represented in terms of Schur functions. A suitable base of any weight space is given. Littlewood-Richardson rule appears in the linear relations among weight vectors.

Hermann Riecke

Recent experiments on convection in binary mixtures have shown that the interaction between localized waves (pulses) can be repulsive as well as {\it attractive} and depends strongly on the relative {\it orientation} of the pulses. It is demonstrated that the concentration mode, which is characteristic of the extended Ginzburg-Landau equations introduced rec

Hans J. Haubold, Arak Mathai Mathai

Hydrostatic equilibrium and energy conservation determine the conditions in the gravitationally stabilized solar fusion reactor. We assume a matter density distribution varying non-linearly through the central region of the Sun. The analytic solutions of the differential equations of mass conservation, hydrostatic equilibrium, and energy conservation, togeth

Won T. Kim, Julian Lee

We define the Bondi energy for two-dimensional dilatonic gravity theories by generalizing the known expression of the ADM energy. We show that our definition of the Bondi energy is exactly the ADM energy minus the radiation energy at null infinity. An explicit calculation is done for the evaporating black hole in the RST model with the Strominger&#39;s ghost

Won T. Kim, Julian Lee, Young Jai Park

We explicitly show that the net number of degrees of freedom in the two-dimensional dilaton gravity is zero through the Hamiltonian constraint analysis. This implies that the local space-time dependent physical excitations do not exist. From the linear perturbation around the black hole background, we explicitly prove that the exponentially growing mode with

Tetsuo Hatsuda

Firstly, I give a brief summary of the current understanding of QCD below and near $T_c$ (the critical temperature of the chiral transition). Some emphases are put on the qualitative difference between the Yukawa regime ($T \sim 0)$ and the Hagedorn regime ($T \sim T_c$). Secondly, the dynamical phenomena associated with the chiral transition, in particular,

Rani Nelken, Nissim Francez

This paper presents an analysis of temporal anaphora in sentences which contain quantification over events, within the framework of Discourse Representation Theory. The analysis in (Partee 1984) of quantified sentences, introduced by a temporal connective, gives the wrong truth-conditions when the temporal connective in the subordinate clause is &#34;before&