October 1995 arXiv papers

Shyamoli Chaudhuri, George Hockney, Joseph D. Lykken

We obtain three generation SU(3)_c X SU(2)_L X U(1)_Y string models in all of the exactly solvable (0,2) constructions sampled by fermionization. None of these examples, including those that are symmetric abelian orbifolds, rely on the Z_2 X Z_2 orbifold underlying the NAHE basis. We present the first known three generation models for which the hypercharge n

Kevin C. K. Chan, Robert B. Mann

We present a new class of spinning black hole solutions in $(2+1)$-dimensional general relativity minimally coupled to a dilaton with potential $e^{bϕ}Λ$. When $b=4$, the corresponding spinning black hole is a solution of low energy $(2+1)$-dimensional string gravity. Apart from the limiting case of the $BTZ$ black hole, these spinning black holes have no in

D. Fox, D. R. Bowman, G. C. Ball, A. Galindo-Uribarri

The response of an array of plastic phoswich detectors to ions of $1\le Z\le 18$ has been measured from $E/A$=12 to 72 MeV. The detector response has been parameterized by a three parameter fit which includes both quenching and high energy delta-ray effects. The fits have a mean variation of $\le 4\%$ with respect to the data.

Juan Mateos Guilarte

The physics of the bare Seiberg-Witten action, without supersymmetric partners, is considered in the framework of standard Quantum Field Theory. The topological analysis related to the solutions of the Seiberg-Witten equations is performed and the phase structure of the model is analysed.

Paul S. Aspinwall, Jan Louis

We consider the general case of N=2 dual pairs of type IIA/heterotic string theories in four dimensions. We show that if the type IIA string in this pair can be viewed as having been compactified on a Calabi-Yau manifold in the usual way then this manifold must be of the form of a K3 fibration. We also see how the bound on the rank of the gauge group of the

A. I. Bugrij, V. N. Shadura

The massive scalar field with $λφ^4$ interaction placed in $(3+1)$ dimensional box is considered. The sizes of the box are $V\times β$ $(V=L^3$ is the volume, $T=1/β$ is the temperature). The free energy is evaluated up to the 2nd order of $PT$. The averaging on the vacuum fluctuations is separated from the averaging on the thermal fluctuations explicitly. A

Satoru Ikehara, Satoshi Shirai, Akio Yokoo, Hiromi Nakaiwa

Recently, several types of Japanese-to-English machine translation systems have been developed, but all of them require an initial process of rewriting the original text into easily translatable Japanese. Therefore these systems are unsuitable for translating information that needs to be speedily disseminated. To overcome this limitation, a Multi-Level Trans

B. Pire

This is a pedagogical review on polarized structure functions .

E. Marco, E. Oset, P. Fernández de Córdoba

We revise the conventional nuclear effects of Fermi motion, binding and pionic effects in deep inelastic lepton scattering using a relativistic formalism for an interacting Fermi sea and the local density approximation to translate results from nuclear matter to finite nuclei. In addition we also consider effects from rho-meson renormalization in the nucleus

Keith R. Dienes, Alon E. Faraggi, John March-Russell

We explore the extent to which string theories with higher-level gauge symmetries and non-standard hypercharge normalizations can reconcile the discrepancy between the string unification scale and the GUT scale extrapolated from the Minimal Supersymmetric Standard Model (MSSM). We determine the phenomenologically allowed regions of (k_Y,k_2,k_3) parameter sp

R. D. Ball, S. Forte, G. Ridolfi

We perform a full next-to-leading analysis of the the available experimental data on the polarized structure function g_1 of the nucleon, and give a precise determination of its singlet axial charge together with a thorough assessment of the theoretical uncertainties. We find that the data are now sufficient to separately determine first moments of the polar

Marc-Thierry Jaekel, Serge Reynaud

We analyze the transformation of quantum fields under conformal coordinate transformations from inertial to accelerated frames, in the simple case of scalar massless fields in a two-dimensional spacetime, through the transformation of particle number and its spectral density. Particle number is found to be invariant under conformal coordinate transformations

Xuemin Jin, Derek B. Leinweber

QCD sum rules for vector mesons (rho, omega, phi) in nuclear matter are reexamined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays a crucial role in determining the validity of a sum rule. The uncertainties arising from less than precise knowledge of t

A. Bianconi, M. Radici

The reliability of the models describing the Final-State Interactions (FSI) in (e,e$'$p) scattering at high proton energies is an important issue in view of the experiments planned at CEBAF. One of the most popular approaches adopted, the Glauber method, involves the linearization of the wave equation for the ejected proton travelling through the residua

W. Haeberli, Barry R. Holstein

The status of the field of nuclear parity violation---both experimental and theoretical---is reviewed, with special emphasis on those results which have been obtained since the 1985 review article by Adelberger and Haxton.

Lutz Jaede, Heinrich Viktor v. Geramb

We investigate self-interacting scalar, pseudoscalar and vector meson fields and their influence on NN interactions. Due to the self--interaction one has to solve nonlinear field equations which allow solitary wave solutions. A propability amplitude for the propagation of these solutions is calculated which can be applied in a One-Boson-Exchange Potential (O

Catherine Stampfl, Matthias Scheffler

Recent experiments performed at high pressures indicate that ruthenium can support unusually high concentrations of oxygen at the surface. To investigate the structure and stability of high coverage oxygen structures, we performed density functional theory calculations, within the generalized gradient approximation, for O adlayers on Ru(0001) from low covera

Jun-Hyung Cho, Matthias Scheffler

The ground-state properties of Fe, Co, and Ni are studied with the linear-augmented-plane-wave (LAPW) method and norm-conserving pseudopotentials. The calculated lattice constant, bulk modulus, and magnetic moment with both the local-spin-density approximation (LSDA) and the generalized gradient approximation (GGA) are in good agreement with those of all-ele

Jie Wu

We give a specific product decomposition of the base-point path connected component of the triple loop space of the suspension of the projective plane.

Ken Halpern, Kerson Huang

We study the eigenvectors of the renormalization-group matrix for scalar fields at the Gaussian fixed point, and find that that there exist ``relevant'' directions in parameter space. They correspond to theories with exponential potentials that are nontrivial and asymptotically free. All other potentials, including polynomial potentials, are ``irrele

V. Narayanan, M. Sivakumar

We study the $W_\infty$ algebra in the Calegero-Sutherland model using the exchange operators. The presence of all the sub-algebras of $W_\infty$ is shown in this model. A simplified proof for this algebra, in the symmetric ordered basics, is given. It is pointed out that the algebra contains in general, nonlinear terms. Possible connection to the nonlinear

Valeri V. Dvoeglazov

Amplitudes for boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the used model is the Weinberg's $2(2j+1)$ component formalism for describing a particle of spin $j$, recently developed substantially. The boson-boson amplitude is then compared with the

Valeri V. Dvoeglazov

Problems connected with a choice of the spinorial basis in the $(j,0)\oplus (0,j)$ representation space are discussed. As shown it has profound significance in the relativistic quantum theory. From the methodological viewpoint this fact is related with the important dynamical role played by space-time symmetries for all kind of interactions.

Ch. Devchand, V. Ogievetsky

Self-dual gauge potentials admit supersymmetric couplings to higher-spin fields satisfying interacting forms of the first order Dirac--Fierz equation. The interactions are governed by conserved currents determined by supersymmetry. These super-self-dual Yang-Mills systems provide on-shell supermultiplets of arbitrarily extended super-Poincaré algebras; class

Debashis Ghoshal

We study some properties of a singular Landau-Ginzburg family characterized by the multi-variable superpotential $W=-X^{-1}(Y_1Y_2)^{n-1} + {1\over n} (Y_1Y_2)^n - Y_3Y_4$. We will argue that (the infra-red limit of) this theory describes the topological degrees of freedom of the $c=1$ string compactified at $n$ times the self-dual radius. We also briefly co

Georg Junker, Stephan Matthiesen, Akira Inomata

A recent development of the studies on classical and quasi-classical properties of supersymmetric quantum mechanics in Witten's version is reviewed. First, classical mechanics of a supersymmetric system is considered. Solutions of the classical equations of motion are given and their properties are discussed in some detail. The corresponding quantum mode

Ashoke Sen

Spectrum of elementary string states in type II string theory contains ultra-short multiplets that are marginally stable. $U$-duality transformation converts these states into bound states at threshold of $p$-branes carrying Ramond-Ramond charges, and wrapped around $p$-cycles of a torus. We propose a test for the existence of these marginally stable bound s

P. Pouliot, M. J. Strassler

We study supersymmetric $SU(N-4)$ gauge theories with a symmetric tensor and $N$ antifundamental representations. The theory with $W=0$ has a dual description in terms of a non-chiral $Spin(8)$ theory with one spinor and $N$ vectors. This duality flows to the $SO(N)$ duality of Seiberg and to a duality proposed by one of us. It also flows to dualities for a

E. S. Cheb-Terrab

A package of Maple 5.3 commands for doing calculations with anticommutative variables is presented.

S. V. Goloskokov

It is shown that the transverse single spin asymmetry in polarized diffractive $Q \bar Q$ production depends strongly on the spin structure of the pomeron coupling. It is concluded that the spin properties of quark-pomeron and proton-pomeron vertices can be studied in future HERA-N experiments.

Valeri V. Dvoeglazov

Due to the standard electroweak model we have become accustomed to think about a neutrino $ν$ and its antineutrino $\bar ν$ as distinct particles. However, it has long been recognized that the apparent distinction between them may be only an illusion. Implying these words of Prof. B. Kayser we give an alternative insight in the physics of neutral particles (

Xerxes Tata

We briefly review the current status and future prospects for supersymmetry searches at colliders, and discuss strategies by which further information about sparticle properties may be obtained at the LHC.

V. Barger, S. Fleming, R. J. N. Phillips

It has been proposed that the large cross sections for prompt $ψ$, $ψ'$, and $χ_c$ production at the Fermilab Tevatron $p\bar p$ collider can be explained by a dominant color-octet term in the fragmentation function for a gluon to split into quarkonium. We show that this mechanism makes testable predictions for double-quarkonium $ψψ$, $ψψ'$, $ψχ_c$,

Axel Kwiatkowski, Matthias Steinhauser

The renormalized mass of the bottom quark is calculated at the two loop level to order ${\cal O}(α_s G_F M_t^2)$ in the $\msbar$ renormalization scheme. Different strategies for the computation are outlined. The result is applied to the partial decay rate $Γ(H\rightarrow b\bar{b})$ of the Higgs boson into bottom quarks. Expressing the width in terms of the r

S. Dawson, G. Valencia

We calculate the typical size of loop corrections to electroweak observables arising from non-standard $Z {\overline t } t$ and $W t b$ vertices. We use an effective Lagrangian formalism based on the electroweak gauge group $SU(2)_L\times U(1)_Y \rightarrow U(1)_{EM}$. Limits on the non-standard model top quark couplings from electroweak observables are pres

B. Pire

Determining how much spin is carried by gluon in a polarized proton is a fundamental problem which cannot be resolved by completely inclusive deep inelastic measurements. Hadroproduction of heavy flavors is very sensitive to the gluon content of hadrons. We show that $χ_2 (3555)$ production in polarized proton-proton collisions is a good candidate reaction t

Paulo F. Bedaque, Markus A. Luty

We consider flavor breaking in the the octet and decuplet baryon masses at second order in large-$N$ chiral perturbation theory, where $N$ is the number of QCD colors. We assume that $1/N \sim 1/N_F \sim m_s / Λ\gg m_{u,d}/Λ, α_{EM}$, where $N_F$ is the number of light quark flavors, and $m_{u,d,s} / Λ$ are the parameters controlling $SU(N_F)$ flavor breakin

W. Koepf, L. L. Frankfurt, M. Strikman

We study the possible contribution of the nucleon's virtual meson cloud to the sea quark distribution as observed in deep inelastic lepton scattering. We adjust the meson-nucleon cut-offs to the large-x tails of the antiquark distributions, find qualitatively different behavior in the flavor singlet and non-singlet channels and study the scale dependence

M. Galdón, R. Pérez Ochoa, M. A. Sanchis-Lozano, J. A. Valls

We discuss the feasibility of the observation of the signal from $B_c$ mesons in the ATLAS experiment at the LHC. In particular, we address the decay mode $B_c{\rightarrow}J/ψπ$ followed by the leptonic decay $J/ψ{\rightarrow}μ^+μ^-$, which should permit an accurate measurement of the $B_c$ mass. We performed a Monte Carlo study of the signal and background

Ming Lu, Martin J. Savage, James Walden

V-spin symmetry ($s \leftrightarrow d$ symmetry) forbids the radiative decay $Ξ_{c2}^{0*} \rightarrow Ξ_{c1}^0 γ$ in the SU(3) limit. The quark mass term breaks V-spin symmetry and the leading nonanalytic contribution to the radiative decay amplitude is computable in heavy baryon chiral perturbation theory. The radiative decay branching ratio is determined b

Chulwoo Jung

We discuss the properties of a class of saddle point solutions in SU(2) in three dimensions (SU$(2)_3$), exhibiting localized peaks in the action. These configurations are generated by deterministic cooling and extremizing algorithms from analytic configurations. They share some characteristics with cooled and extremized Monte Carlo generated lattices. We ha

Dong Chen

We report the hadron mass spectrum obtained on a $16^3 \times 40$ lattice at $β= 5.7$ using two flavors of staggered fermions with $m a = 0.01$. We calculate the masses of excited states that have the same quantum numbers as the $π$, $ρ$ and $N$. They are obtained by a combined analysis of the hadron correlators from sources of size $16^3$ and $8^3$. We also

L. H. Ford, Thomas A. Roman

Recently a bound on negative energy densities in four-dimensional Minkowski spacetime was derived for a minimally coupled, quantized, massless, scalar field in an arbitrary quantum state. The bound has the form of an uncertainty principle-type constraint on the magnitude and duration of the negative energy density seen by a timelike geodesic observer. When s

C. Alvarez, R. B. Mann

We consider the possibility of using measurements of anomalous magnetic moments of elementary particles as a possible test of the Einstein Equivalence Principle (EEP). For the class non-metric theories of gravity described by the \tmu formalism we find several novel mechanisms for breaking the EEP, and discuss the possibilities of setting new empirical const

Oscar A. Reula, Gabriel B. Nagy

In this paper we investigate some properties, including causality, of a particular class of relativistic dissipative fluid theories of divergence type. This set is defined as those theories coming from a statistical description of matter, in the sense that the three tensor fields appearing in the theory can be expressed as the three first momenta of a suitab

Marco Litterio, Leszek M. Sokołowski, Zdzisław A. Golda, Luca Amendola

Vacuum multidimensional cosmological models with internal spaces being compact $n$-dimensional Lie group manifolds are considered. Products of 3-spheres and $SU(3)$ manifold (a novelty in cosmology) are studied. It turns out that the dynamical evolution of the internal space drives an accelerated expansion of the external world (power law inflation). This ge

Enrico Carugno, Marco Litterio, Franco Occhionero, Giuseppe Pollifrone

We extend to multidimensional cosmology Vilenkin's prescription of tunnelling from nothing for the quantum origin of the observable Universe. Our model consists of a $D+4$-dimensional spacetime of topology ${\cal R}\times {\cal S}^3 \times{\cal S}^D$, with a scalar field (``chaotic inflaton'') for the matter component. Einstein gravity and Casimi

Jacques Demaret, Laurent Querella

We use Boulware's Hamiltonian formalism of quadratic gravity theories in order to analyze the classical behaviour of Bianchi cosmological models for a Lagrangian density containing quadratic terms in the curvature. For this purpose we define a canonical transformation which leads to a clear distinction between two main variants of the quadratic theory, n

Chris Isham

A discursive, non-technical, analysis is made of some of the basic issues that arise in almost any approach to quantum gravity, and of how these issues stand in relation to recent developments in the field. Specific topics include the applicability of the conceptual and mathematical structures of both classical general relativity and standard quantum theory.

Hans - Juergen Schmidt

Mechanics is developed over a differentiable manifold as space of possible positions. Time is considered to fill a one--dimensional Riemannian manifold, so having the metric as lapse. Then the system is quantized with covariant instead of partial derivatives in the Schrödinger operator. Consequences for quantum cosmology are shortly discussed.

D. Burghelea, L. Friedlander, T. Kappeler

We extend the definition of analytic and Reidemeister torsion from closed compact Riemannian manifolds to compact Riemannian manifolds with boundary $(M, \partial M)$, given a flat bundle $\Cal F$ of $\Cal A$-Hilbert modules of finite type and a decomposition of the boundary $\partial M =\partial_- M \cup \partial_+ M$ into disjoint components. In particular

Akhil Ranjan

In this paper we show that a substantial Riemannian submersion of S(15) with 7- dimensional fibres is congruent to the standard Hopf fibration. As a consequence we prove a slightly weak form of of the Diameter Rigidity theorem for the Cayley plane which is considerably stronger than the very recent Radius Rigidity Theorem of Wilhelm.

T. Antal, Z. Racz

Edwards--Wilkinson type models are studied in 1+1 dimensions and the time-dependent distribution, P_L(w^2,t), of the square of the width of an interface, w^2, is calculated for systems of size L. We find that, using a flat interface as an initial condition, P_L(w^2,t) can be calculated exactly and it obeys scaling in the form <w^2>_\infty P_L(w^2,t) = Phi(w^

Giuseppe Iannaccone, Bruno Pellegrini

In this paper we show an approach to electron transport in double barrier structures which unifies the well known sequential and resonant tunneling models in the widest range of transport regimes, from completely coherent to completely incoherent. In doing so, we make a clear distinction between ``approaches&#39;&#39; and ``transport regimes,&#39;&#39; in or

David Clarke, Steven Strong

We present a pedagogical account of our approach to the problem of Luttinger liquids coupled by interliquid single particle hopping. It is shown that the key issue is that of coherence/incoherence of interliquid hopping, and not of relevance/irrelevance in a renormalization group sense. A clear signal of coherence, present in the case of coupled Fermi liquid

T. J. Hagenaars, J. E. van Himbergen, Jorge V. Jose, P. H. E. Tiesinga

We study the propagation properties of a single vortex in square Josephson-junction arrays (JJA) with free boundaries and subject to an applied dc current. We model the dynamics of the JJA by the resistively and capacitively shunted junction (RCSJ) equations. For zero Stewart-McCumber parameter $β_c$ we find that the vortex always escapes from the array when

G. B. Mindlin, P. T. Boyd, J. L. Caaminos, J. A. Nunez

We report the discovery of a low dimensional dynamical system in a 5.5 hr Hubble Space Telescope High Speed Photometer observation of a rapidly oscillating star. The topological description of the phase space orbits is given, as well as a dynamical model which describes the results. This model should motivate theorists of stellar pulsations to search for a t

Michael J. West

A new model for the formation of active galaxies is described. A key feature of this model is the idea that the birth of black holes in the centers of supergiant galaxies is strongly influenced by the large-scale distribution of matter in the universe. This conjecture can successfully explain two observed phenomena: the alignment of the radio, optical and in

John D. Anderson, Mark Gross, Eunice L. Lau, Kenneth L. Nordtvedt

The year 1996 will mark the initiation of a number of new space missions to the planet Mars from which we expect to obtain a rich set of data, including spacecraft radio tracking data. Anticipating these events, we have analyzed the feasibility of testing a violation of the strong equivalence principle (SEP) with Earth-Mars ranging. Using analytic and numeri

E. Lega, A. Bijaoui, J. -M. Alimi, H. Scholl

We propose a morphological multi-scale analysis of large-scale structures obtained by computer simulations and by observations. Structures are obtained at different scales by applying a wavelet transform on the observed and simulated data. Application of a segmentation algorithm allows a quantitative morphological description of the structures at each scale.

E. Olszewski, C. Pryor, T. Armandroff

We use a large set of radial velocities in the Ursa Minor and Draco dwarf spheroidal galaxies to search for binary stars and to infer the binary frequency. Of the 118 stars in our sample with multiple observations, six are velocity variables with $χ^2$ probabilities below 0.001. We use Monte Carlo simulations that mimic our observations to determine the effi

Anne A. Thoul, David H. Weinberg

Photoionization by the high-redshift ultraviolet radiation background heats low density gas before it falls into dark matter potential wells, and it eliminates the neutral hydrogen and singly ionized helium that dominate cooling of primordial gas at temperatures of $10^4-10^5$K. We investigate the influence of photoionization on galaxy formation using high-r

S. M. Hall, C. J. Clarke, J. E. Pringle

We investigate the response of a circumstellar accretion disc to the fly-by of a perturbing mass on a parabolic orbit. The energy and angular momentum transferred during the encounter are calculated using a reduced three-body method. In almost all close encounters the energy and angular momentum transfer is dominated by disc material becoming unbound from th

Frank Sottile

We extend the classical Schubert calculus of enumerative geometry for the Grassmann variety of lines in projective space from the complex realm to the real. Specifically, given any collection of Schubert conditions on lines in projective space which generically determine a finite number of lines, we show there exist real generic conditions determining the ex

G. Parzen

It will be shown that starting from a coordinate system where the 6 phase space coordinates are linearly coupled, one can go to a new coordinate system where the motion is uncoupled by means of a linear transformation. The original coupled coordinates and the new uncoupled coordinates are related by a 6x6 matrix, R. R will be called the decoupling matrix. It

A. Gorsky, A. Marshakov

We discuss a general approach to the nonperturbative treatment of quantum field theories based on existence of effective gauge theory on auxiliary &#39;&#39;spectral&#34; Riemann curve. We propose an effective formulation for the exact solutions to some examples of $2d$ string models and $4d$ supersymmetric Yang-Mills theories and consider their natural gene

M. Bershadsky, V. Sadov, C. Vafa

We study the mechanism for appearance of massless solitons in type II string compactifications. We find that by combining $T$-duality with strong/weak duality of type IIB in 10 dimensions enhanced gauge symmetries and massless solitonic hypermultiplets encountered in Calabi-Yau compactifications can be studied perturbatively using D-strings (the strong/weak

Trygve Johnsen, Steven L. Kleiman

We prove the following form of the Clemens conjecture in low degree. Let $d\le9$, and let $F$ be a general quintic threefold in $\IP^4$. Then (1)~the Hilbert scheme of rational, smooth and irreducible curves of degree $d$ on $F$ is finite, nonempty, and reduced; moreover, each curve is embedded in $F$ with normal bundle $Ø(-1)\oplusØ(-1)$, and in $\IP^4$ wit

Sheldon Katz

Calculations of the number of curves on a Calabi-Yau manifold via an instanton expansion do not always agree with what one would expect naively. It is explained how to account for continuous families of instantons via deformation theory and excess intersection theory. The essential role played by degenerate instantons is also explained. This paper is a sligh

Hugh Chipman

In data sets with many predictors, algorithms for identifying a good subset of predictors are often used. Most such algorithms do not account for any relationships between predictors. For example, stepwise regression might select a model containing an interaction AB but neither main effect A or B. This paper develops mathematical representations of this and

Igor Bandos, Dmitrij Sorokin, Dmitrij Volkov

We present new $n=(1,1)$ and $n=(1,0)$ supersymmetric generalization of the Liouville equation, which originate from a geometrical approach to describing the classical dynamics of Green--Schwarz superstrings in $N=2,~D=3$ and $N=1,~D=3$ target superspace. Considered are a zero curvature representation and Bäcklund transformations associated with the supersym

C. T. H. Davies, A. J. Lidsey, K. Hornbostel, G. P. Lepage

We update our results for the heavy-heavy spectrum at $\beta$ = 5.7, using NRQCD. This includes a scaling comparison with the $\Upsilon$ spectrum at $\beta$ = 6.0 and first lattice predictions for the $B_c$ spectrum.

B. Bakalov, E. Horozov, M. Yakimov

For each r = (r_1, r_2,...,r_N) we construct a highest weight module M_r of the Lie algebra W_{1+infty}. The highest weight vectors are specific tau-functions of the N-th Gelfand--Dickey hierarchy. We show that these modules are quasifinite and we give a complete description of the reducible ones together with a formula for the singular vectors. This paper i

J. T. Chalker, A. Dohmen

We study localization in layered, three-dimensional conductors in strong magnetic fields. We demonstrate the existence of three phases - insulator, metal and quantized Hall conductor - in the two-dimensional parameter space obtained by varying the Fermi energy and the interlayer coupling strength. Transport in the quantized Hall conductor occurs via extended

Shrawan Kumar

This lecture note is devoted to prove that the space of vacua is isomorphic with the space of generalized theta functions (joint work with M.S. Narasimhan, and A. Ramanathan)

A. P. Balachandran, G. Bimonte, E. Ercolessi, G. Landi

Lattice discretizations of continuous manifolds are common tools used in a variety of physical contexts. Conventional discrete approximations, however, cannot capture all aspects of the original manifold, notably its topology. In this paper we discuss an approximation scheme due to Sorkin which correctly reproduces important topological aspects of continuum

Shaun Cole, Cedric Lacey

We use a set of large cosmological N-body simulations to study the internal structure of dark matter haloes which form in scale-free models. We find that the radius r_178 corresponding to a mean interior overdensity of 178 accurately delineates the quasi-static halo interior from the surrounding infalling material, in agreement with the simple spherical coll

Igor A. Bandos

It is shown that a zero curvature representation for $D$-- dimensional $p$-- brane equations of motion originates naturally in the geometric (Lund- Regge- Omnes) approach. To study the possibility to use this zero curvature representation for investigation of nonlinear equations of $p$-- branes, the simplest case of $D$-- dimensional string ($p=1$) is consid

Frank Cuypers

We consider the production of scalar and vector leptoquarks in $e^-e^-$ collisions. Although this reaction is not competitive with {\em e.g.} $e^-γ$ scattering for discovering these heavy states, it is the main process susceptible of differentiating two important classes of leptoquarks.

N. Itzhaki

We discuss the limitations on space time measurement in the Schwarzchild metric. We find that near the horizon the limitations on space time measurement are of the order of the black hole radius. We suggest that it indicates that a large mass black hole cannot be described by means of local field theory even at macroscopic distances and that any attempt to d

T. V. Duong, B. Dutta, E. Keith

We compare the branching ratios for $b\rightarrow s\gamma$ and $\mu\rightarrow e\gamma$ in terms of constraining the parameter space in supersymmetric SO(10) grand unification models where supersymmetry is broken softly near the Planck scale by generationally symmetric operators. We observe two general cases. One with small $\tan\beta =2$ and the other one w

B. Grammaticos, A. Ramani

We propose a discrete form for an equation due to Gambier and which belongs to the class of the fifty second order equations that possess the Painleve property. In the continuous case, the solutions of the Gambier equation is obtained through a system of Riccati equations. The same holds true in the discrete case also. We use the singularity confinement crit

Terry Gannon

The classification of CFTs has an important subproblem, namely classifiying the partition functions for WZW theories. This subproblem is intimately connected to the modular behaviour of the characters of affine algebras. This paper addresses the classification of the largest class of these -- the natural generalization to any affine algebra of the A-series,

Bernd Kohler, Paolo Ruggerone, Matthias Scheffler, Erio Tosatti

The possible occurrence of either a charge-density-wave or a Kohn anomaly is governed by the presence of Fermi-surface nesting and the subtle interaction of electrons and phonons. Recent experimental and theoretical investigations suggest such an effect for the hydrogen covered Mo and W(110) surfaces. Using density-functional theory we examine the electronic

Joseph Polchinski, Andrew Strominger

Lorentz-invariant expectation values for antisymmetric tensor field strengths in Calabi-Yau compactification of IIA string theory are considered. These are found to impart magnetic and/or electric charges to the dilaton hypermultiplet. This results in a potential which can have supersymmetric minima at zero coupling or at conifold points in the moduli space.

D. Kutasov, A. Schwimmer, N. Seiberg

We study in detail the space of perturbations of a pair of dual $N=1$ supersymmetric theories based on an $SU(N_c)$ gauge theory with an adjoint $X$ and fundamentals with a superpotential which is polynomial in $X$. The equivalence between them depends on non-trivial facts about polynomial equations, i.e.\ singularity theory. The classical chiral rings of th

G. Lambiase, V. V. Nesterenko

A consistent method for calculating the interquark potential generated by the relativistic string with massive ends is proposed. In this approach the interquark potential in the model of the Nambu--Goto string with point--like masses at its ends is calculated. At first the calculation is done in the one--loop approximation and then the variational estimation

V. E. Rochev, P. A. Saponov

In this talk we discuss a new approximation scheme for non-perturbative calculations in a quantum field theory which is based on the fact that the Schwinger equation of a quantum field model belongs to the class of singularly perturbed equations. The self-interacting scalar field and the Gross-Neveu model are taken as the examples and some non-perturbative s

A. H. Chamseddine

We present a derivation of the general form of the scalar potential in Yang-Mills theory of a non-commutative space which is a product of a four-dimensional manifold times a discrete set of points. We show that a non-trivial potential without flat directions is obtained after eliminating the auxiliary fields only if constraints are imposed on the mass matric

M. Eliashvili, G. Tsitsishvili

The relativistic model with two types of planar fermions interacting with the Chern-Simons and Maxwell fields is applied to the study of anyon superconductor. It is demonstrated, that the Meissner effect can be realized in the case of the simultaneous presence of the fermions with a different magnetic moment interactions. Under the certain conditions there o

Igor A. Bandos

The previously proposed generalized action principle approach to supersymmetric extended objects is considered in some details for the case of heterotic string in $D=3, 4, 6 ~and~ 10$ space--time dimensions. The proof of the &#39;off--shell&#39; superdiffeomorphism invariance of the generalized action is presented. The doubly supersymmetric geometric approac

Giulia Ricciardi

A status report on the theory of radiative rare $B$ decays in the standard model is presented, with focus on inclusive decays $B \rightarrow X_{(s,d)}\, γ$ and exclusive decays $B \rightarrow (K^\ast,ω,ρ) \, γ$. CP asymmetries are also briefly discussed.

R. D. Tangerman, P. J. Mulders

The twist-three distributions $g_2(x)$ and $h_2(x)$ are defined as quark-field matrix elements between polarized hadron states. They can be written in terms of quark-mass and gluonic operators, after which the Burkhardt-Cottingham sum rule for $g_2$ can be derived and a similar sum rule for $h_2$. Their role in the Drell-Yan double-spin asymmetry $A_{LT}$ is

Wolfgang Ochs, Jacek Wosiek

Angular correlations of partons have been derived for high energy jets in QCD. Interesting new scaling properties with two redundant variables (jet energy $P$ and jet opening angle $Θ$) emerge which can be tested within a parton-hadron duality picture. Recent results from LEP support the scaling in $Θ$; the scaling in both $P$ and $Θ$ could be tested with je

A. Davidson, T. Schwartz, K. C. Wali

The Universal Seesaw pattern coupled with a Light$\leftrightarrow$Heavy symmetry principle leads to the Diophantine equation $\displaystyle N = \sum_{i=1}^Nn_i$, where $n_i\geq 0$ and distinct. Its unique non-trivial solution $(3=0+1+2)$ gives rise to the geometric mass hierarchy $m_W$, $m_Wε$, $m_Wε^2$ for $N=3$ fermion families. This is realized in a model

J. Hisano

The Peccei-Quinn symmetric extension of the missing-partner model in the supersymmetric SU(5) grand unified model is consistent with the observed stability of the proton, even in the large $\tanβ$ region ($\simeq 50-60$) expected from the Yukawa unification. Moreover, the SU(5) gauge coupling constant remains small enough for the perturbative description of

G. Giachetta, G. Sardanashvily

Differential conservation laws in Lagrangian field theory are usually related to symmetries of a Lagrangian density and are obtained if the Lie derivative of a Lagrangian density by a certain class of vector fields on a fiber bundle vanishes. However, only two field models meet this property in fact. In gauge theory of exact internal symmetries, the Lie deri

C. M. Naón, M. C. von Reichenbach, M. L. Trobo

We study the Tomonaga-Luttinger model in the presence of magnetic (Kondo-like) impurities. By using a recently proposed field-theoretical approach to non-local bosonization we obtain the effective action describing the low-energy charge and spin density fluctuations. From this action the dispersion relations of the collective modes are readily found. We also

D. R. Alfonso, C. Noguez, D. A. Drabold, S. E. Ulloa

The relaxed geometries and electronic properties of the hydrogenated phases of the Si(111)-7$\times$7 surface are studied using first-principles molecular dynamics. A monohydride phase, with one H per dangling bond adsorbed on the bare surface is found to be energetically favorable. Another phase where 43 hydrogens saturate the dangling bonds created by the

A. G. Green, I. I. Kogan, A. M. Tsvelik

We report on a theory of the Skyrmion states which occur in quantum Hall regime near certain filling factors. It is shown that in the limit of zero Zeeman splitting in a realistic temperature range the Skyrmion plasma is a liquid described by the effective model of massive two-dimensional Dirac fermions.