August 1995 arXiv papers — page 2

A. A. Kehagias

We examine the electric-magnetic duality for a U(1) gauge theory on a general 4-manifold. The partition function for such a theory transforms as a modular form of specific weight. However, in the canonical approach, we show that S-duality, like T-duality, is generated by a canonical transformation leading to a modular invariant partition function.

Felix M. Lev

Lorentz invariance of the current operators implies that they satisfy the well-known commutation relations with the representation operators of the Lorentz group. It is shown that if the standard construction of the current operators in quantum field theory is used then the commutation relations are broken by the Schwinger terms.

R. Floreanini, R. Percacci

We consider the gravitational coupling of a scalar field, in a reformulation of General Relativity exhibiting local GL(4) invariance at the classical level. We compute the one-loop contribution of the scalar to the quantum effective potential of the vierbein and find that it does not have GL(4) invariance. The minima of the effective potential occur for a vi

J. P. Gauntlett, J. A. Harvey

We study the dyon spectrum in $N=2$ Super Yang-Mills theory with gauge group $SU(2)$ coupled to $N_f$ matter multiplets in the fundamental representation. For magnetic charge one and two we determine the spectrum explicitly and show that it is in agreement with the duality predictions of Seiberg and Witten. We briefly discuss the extension to higher charge m

S. Kachru, A. Klemm, W. Lerche, P. Mayr

Using heterotic/type II string duality, we obtain exact nonperturbative results for the point particle limit (alpha' -> 0) of some particular four dimensional, N=2 supersymmetric compactifications of heterotic strings. This allows us to recover recent exact nonperturbative results on N=2 gauge theory directly from tree-level type II string theory, which

Evgenyi A. Ivanov

We present a manifestly supersymmetric off-shell formulation of a wide class of $(4,4)$ $2D$ sigma models with torsion and both commuting and non-commuting left and right complex structures in the harmonic superspace with a double set of $SU(2)$ harmonic variables. The distinguishing features of the relevant superfield action are: (i) in general nonabelian a

Nimai C. Mukhopadhyay, J. -F. Zhang, M. Benmerrouche

We extract a parameter $ξ$, a characteristic product of the strong and electromagnetic amplitudes for the N^*(1535), to be (2.20+-0.15) in unit of 10^(-4)MeV^(-1) from the new data on photoproduction of etas off proton.

C. Bachas, T. N. Tomaras

We present some non-topological static wall solutions in two-Higgs extensions of the standard model. They are classically stable in a large region of parameter space, compatible with perturbative unitarity and with present phenomenological bounds.

J. C. D'Olivo, Jose F. Nieves

We compare the use of the Coulomb gauge in finite temperature QED with a recently proposed prescription for covariant gauges, in which only the transverse photon degrees of freedom are thermalized. Using the Landau rule as a guide, we clarify the relation between the retarded electron self-energy and the elements of the self-energy matrix in the real-time fo

Jonathan A. Bagger

Supersymmetry searches are about to enter an important new era. With LEP 200 and the Main Injector, they will, for the first time, begin to probe significant regions of the supersymmetric parameter space. There is a real chance that supersymmetry might indeed be found before the advent of the LHC.

Torbjorn Sjostrand

This is the latest edition of the physics description and manual of the PYTHIA and JETSET programs for event generation in High Energy Physics.

Arnd Leike, Joachim Rose, Tord Riemann

We analyze the $Z$ line shape assuming the existence of an analytic, unitary S-matrix. As an example, from hadron production at LEP we determine $M_{Z}=91.134 \pm 0.020 \pm 0.020 \: ({\rm LEP})$ GeV, $Γ_{Z}=2.506 \pm 0.018$ GeV. This is in accordance with earlier results after performing a shift of the $Z$ mass value of about $\frac{1}{2}Γ_Z^2/M_Z = 34$ MeV.

Michael Creutz

Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are xising, for the two dimensional Ising model, xpotts, for the $q$-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a s

Marc Blatter, Rudolf Burkhalter, Peter Hasenfratz, Ferenc Niedermayer

We define a fixed point topological charge for the two-dimensional O(3) lattice sigma-model which is free of topological defects. We use this operator in combination with the fixed point action to measure the topological susceptibility for a wide range of correlation lengths. The results strongly suggest that it is not a physical quantity in this model. The

A. M. Abrahams, R. H. Price

Nonspherical perturbation theory has been necessary to understand the meaning of radiation in spacetimes generated through fully nonlinear numerical relativity. Recently, perturbation techniques have been found to be successful for the time evolution of initial data found by nonlinear methods. Anticipating that such an approach will prove useful in a variety

Shu Zhang, Gerhard Müller, Joachim Stolze

The recursion method is used to determine the T=0 spin dynamic structure factor S_{zz}(q,ω) in the Luttinger liquid state and in the phase-separated state of the one-dimensional t-J model. As the exchange coupling increases from zero, the dispersions and line shapes of the dominant spin excitations are observed to undergo a major metamorphosis between the fr

S. Franz, F. Ritort

In this paper we present an exact study of the relaxation dynamics of the backgammon model. This is a model of a gas of particles in a discrete space which presents glassy phenomena as a result of {\it entropy barriers} in configuration space. The model is simple enough to allow for a complete analytical treatment of the dynamics in infinite dimensions. We f

Xiaqun Wang, Steffen Mallwitz

Using a new impurity density matrix renormalization group scheme, we establish a reliable picture of how the low lying energy levels of a $S=1$ Heisenberg antiferromagnetic chain change {\it quantitatively} upon bond doping. A new impurity state gradually occurs in the Haldane gap as $J&#39; < J$, while it appears only if $J&#39;/J>γ_c$ with $1/γ_c=0.708$ as

A. Hucht, K. D. Usadel

In this paper the thermodynamics of thin ferromagnetic films are studied in the framework of the classical Heisenberg model with uniaxial anisotropy and long--range dipole interaction. The dependence of the order of the reorientation transition in these systems on the number of layers and on the distribution of anisotropies is investigated using both mean fi

Pal Rujan

A ray-tracing method inspired by ergodic billiards is used to estimate the theoretically best decision rule for a set of linear separable examples. While the Bayes-optimum requires a majority decision over all Perceptrons separating the example set, the problem considered here corresponds to finding the single Perceptron with best average generalization prob

Tae-Suk Kim, D. L. Cox

We present studies of a simple Anderson model Hamiltonian for Ce$^{3+}$ ions in cubic symmetry with three configurations ($f^0$,$f^1$,$f^2$). Our Hamiltonian includes: (i) One-channel Anderson model; (ii) Two-channel Anderson model. Using the third order scaling analysis, we study stability of the non-Fermi liquid fixed point of the two-channel Kondo model f

Karen E. Lochbaum

If an agent does not possess the knowledge needed to perform an action, it may privately plan to obtain the required information on its own, or it may involve another agent in the planning process by engaging it in a dialogue. In this paper, we show how the requirements of knowledge preconditions can be used to account for information-seeking subdialogues in

S. Colombi, F. R. Bouchet, L. Hernquist

We measure the scaling properties of the probability distribution of the smoothed density field in $N$-body simulations of expanding universes with scale-free initial power-spectra, with particular attention to the predictions of the stable clustering hypothesis. We concentrate our analysis on the ratios $S_Q(\ell)\equiv {\bar ξ}_Q/{\bar ξ}_2^{Q-1}$, $Q \leq

Michael J. West, Patrick Cote, Christine Jones, William Forman

Globular cluster populations of supergiant elliptical galaxies are known to vary widely, from extremely populous systems like that of UGC 9799, the centrally dominant galaxy in Abell 2052, to globular-cluster-poor galaxies such as NGC 5629 in Abell 2666. Here we propose that these variations point strongly to the existence of a population of globular cluster

Tamara T. Helfer, Leo Blitz

We present high-resolution CO, HCN, and 13CO maps of the inner arcminute of NGC 1068 made with the BIMA interferometer. Several features appear in the CO map which have not previously been observed: (1) a firm detection of CO line emission from a compact region centered on the nucleus of the galaxy; (2) the detection of a triplet velocity structure character

M. A. Hendry, J. F. L. Simmons

In this paper we outline the framework of mathematical statistics with which one may study the properties of galaxy distance estimators. We describe, within this framework, how one may formulate the problem of distance estimation as a Bayesian inference problem, and highlight the crucial question of how one incorporates prior information in this approach. We

M. A. Hendry, S. Rauzy, P. Salucci, M. Persic

In this paper we derive a Tully Fisher relation from measured I band photometry and H$α$ rotation curves of a large survey of southern sky spiral galaxies, obtained in Persic \& Salucci (1995) by deprojecting and folding the raw H$α$ data of Mathewson, Ford \& Buchhorn (1992). We calibrate the relation by combining several of the largest clusters in the surv

D. Schaerer, A. de Koter, W. Schmutz, A. Maeder

In Schaerer et al. (1995, Paper I) we have presented the first &#34;combined stellar structure and atmosphere models&#34; (CoStar) for massive stars, which consistently treat the entire mass loosing star from the center out to the outer region of the stellar wind. The models use up-to-date input physics and state-of-the-art techniques to model both the stell

D. Schaerer, A. de Koter, W. Schmutz, A. Maeder

We present the first &#34;combined stellar structure and atmosphere models&#34; (CoStar) for massive stars, which consistently treat the entire mass loosing star from the center out to the asymptotic wind velocity. The models use up-to-date input physics and state-of-the-art techniques to model both the stellar interior and the spherically expanding non--LTE

Yu Zhang, Peter Anninos, Michael L. Norman

We have performed a multi-species hydrodynamical simulation of the formation and evolution of Lyman alpha clouds in a flat CDM dominated universe with an external flux of ionizing radiation. We solve the fully coupled non-equilibrium rate equations for the following species: H, H^+, H^-, H_2, H_2^+, He, He^+, He^{++}, and e^-. The statistical properties of t

Zhang-Ju Liu, Alan Weinstein, Ping Xu

In his study of Dirac structures, a notion which includes both Poisson structures and closed 2-forms, T. Courant introduced a bracket on the direct sum of vector fields and 1-forms. This bracket does not satisfy the Jacobi identity except on certain subspaces. In this paper we systematize the properties of this bracket in the definition of a Courant algebroi

Johannes Blümlein

The possibility is investigated to measure the polarized structure function $g_1(x,Q^2)$ in the collider mode of HERA operating with a polarized lepton and proton beam. The $x$ dependence of $g_1$ can be measured at a statistical precision of $\sim 20\%~{\rm to}~80\%$ in the range $0.0005 < x < 0.5$ correlated to virtualities $15 < \langle Q^2 \rangle < 3500

Cai-Dian Lu, Zhenjun Xiao

In this paper we calculate the contributions to the branching ratio of $B\to X_s γ$ from the charged Pseudo-Goldstone bosons appeared in one generation Technicolor model. The current $CLEO$ experimental results can eliminate large part of the parameter space in the $m(P^\pm) - m(P_8^\pm)$ plane, and specifically, one can put a strong lower bound on the masse

H. W. Braden, V. M. Buchstaber

The general analytic solution to the functional equation $$ ϕ_1(x+y)= { { \biggl|\matrix{ϕ_2(x)&ϕ_2(y)\crϕ_3(x)&ϕ_3(y)\cr}\biggr|} \over { \biggl|\matrix{ϕ_4(x)&ϕ_4(y)\crϕ_5(x)&ϕ_5(y)\cr}\biggr|} } $$ is characterised. Up to the action of the symmetry group, this is described in terms of Weierstrass elliptic functions. We illustrate our theory by applying it

Andrew Yates, T. W. B. Kibble

The canonical Monte-Carlo algorithm for simulating the production of string-like topological defects at a phase transition is extended by introducing a distribution of domain sizes. A strong correlation is found between the fraction in the form of `infinite' string and the variance of the volume of the regions of constant phase.

L. Biferale, R. Kerr

Non-positive definite, global inviscid invariants similar to helicity are discussed for two types of shell models and evidence for a new role for helicity in Navier-Stokes turbulence is presented. It is suggested that the extra invariants play the role of triggering the intermittent cascade of energy to small scales characterized by pulses. These invariants

Konrad Kuijken

Evidence from a variety of sources points towards the existence of a bar in the central few kpc of the Galaxy. The measurements roughly agree on the direction of the bar major axis, but other parameters (axis ratio, size, pattern speed) are still poorly determined. Current dynamical models are limited by the quality of hydro simulations, the degeneracy of st

Giampiero Esposito

In the one-loop approximation for Euclidean quantum gravity, the boundary conditions which are completely invariant under gauge transformations of metric perturbations involve both normal and tangential derivatives of the metric perturbations $h_{00}$ and $h_{0i}$, while the $h_{ij}$ perturbations and the whole ghost one-form are set to zero at the boundary.

Ling-Lie Chau, Hai-Yang Cheng, B. Tseng

We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effe

T. Futamase, M. Hotta, H. Inoue, M. Yamaguchi

We discuss photon emission from particles decelerlated by the cosmic expansion. This can be interpretated as a kind of bremsstrahlung induced by the Universe geometry. In the high momentum limit its transition probability does not depend on detailed behavior of the expansion.

Micheline Musette, Robert Conte

We consider meromorphic particular solutions of nonlinear ordinary differential equations and perform a perturbation {\it à la} Poincaré making their linearized equation non-Fuchsian at the movable pole and Fuchsian at infinity. When the nonlinear equation possesses movable logarithms, they are detected sooner than with the perturbative (Fuchsian) Painlevé t

P. Kosinski, P. Maslanka, J. Sobczyk

The bicovariant differential calculus on the four-dimensional kappa-Poincare group and the corresponding Lie-algebra like structure are described. The deifferential calculus on the n-dimensional kappa-Minkowski space covariant under the action of the kappa-Poincare group is constructed.

Y. Brihaye, S. Giller, C. Gonera, P. Kosinski

Some properties of central extensions of 2+1 dimensional Galilei group are discussed. It is shown that certain families of extensions are isomorphic. An interpretation of new nontrivial cocycle is offered. A few bibliographical remarks are included.

A. Sibirtsev, K. Tsushima, Amand Faessler

The isobar model and the resonance model are applied for the first analysis of the subthreshold $K^+$-meson production in proton-carbon collisions, which was perfomed at GSI at an emission angle of 40 degrees and a bombarding energy of 1.2 GeV. In this study, we focus on the role of the secondary processes $πN \to K^+ Y$ in normal nuclear matter density. It

Paul S. Aspinwall

Some relationships between string theories and eleven-dimensional supergravity are discussed and reviewed. We see how some relationships can be derived from others. The cases of N=2 supersymmetry in nine dimensions and N=4 supersymmetry in four dimensions are discussed in some detail. The latter case leads to consideration of quotients of a K3 surface times

S. James Gates,

Within a four dimensional manifestly N = 1 supersymmetric action, we show that Wess-Zumino-Novikov-Witten (WZNW) terms can be embedded in an extraordinarily simple manner into a purely chiral superaction. In order to achieve this result it is necessary to assign spin-0 and spin-1/2 degrees of freedom both to chiral superfields and as well to non-minimal scal

Steven B. Giddings

A concise survey of the black hole information paradox and its current status is given. A summary is also given of recent arguments against remnants. The assumptions underlying remnants, namely unitarity and causality, would imply that Reissner Nordstrom black holes have infinite internal states. These can be argued to lead to an unacceptable infinite produc

Kurt Lechner, Mario Tonin

We present a formulation of $N=1,D=10$ Supergravity--Super--Maxwell theory in superspace in which the graviphoton can be described by a 2--form $B_2$ or a 6--form $B_6$, the photon by a 1--form $A_1$ or a 7--form $A_7$ and the dilaton by a scalar $φ$ or an 8--form $φ_8$, the supercurvatures of these fields being related by duality. Duality interchanges Bianc

Luca Salasnich

We study the classical chaos--order transition in the spatially homogenous SU(2) Yang--Mills--Higgs system by using a quantal analog of Chirikov&#39;s resonance overlap criterion. We obtain an analytical estimation of the range of parameters for which there is chaos suppression.

Paul Mansfield

For fields that vary slowly on the scale of the lightest mass the logarithm of the vacuum functional can be expanded as a sum of local functionals, however this does not satisfy the obvious form of the Schrödinger equation. For $φ^4$ theory we construct the appropriate equation that this expansion does satisfy. This reduces the eigenvalue problem for the Ham

A. Ritz, G. C. Joshi

An ansatz is presented for a possible non-associative deformation of the standard Yang-Mills type gauge theories. An explicit algebraic structure for the deformed gauge symmetry is put forward and the resulting gauge theory developed. The non-associative deformation is constructed in such a way that an apparently associative Lie algebraic structure is retain

R. D. Peccei

This review of CP violation focuses on the status of the subject and its likely future development through experiments in the Kaon system and with B-decays. Although present observations of CP violation are perfectly consistent with the CKM model, we discuss the theoretical and experimental difficulties which must be faced to establish this conclusively. In

A. Bernicha, G. Lopez Castro, J. Pestieau

We determine the mass and width of the $Δ^{++}\ (Δ^0)$ resonance from data on $π^+ p\ (π^- p)$ scattering both, in the pole of the $S$-matrix and conventional Breit-Wigner approaches to the scattering amplitude. We provide a simple formula that relates the two definitions for the parameters of the $Δ$. Isospin symmetry breaking in the $\d0-\dm$ system depend

A. Edin, G. Ingelman, J. Rathsman

We introduce soft colour interactions as a novel mechanism to understand the observed events with large rapidity gaps in $ep$ collisions at HERA. Colour exchanges between produced partons and colour-charges in the proton remnant modifies the colour structure for hadronization, such that colour singlet systems may appear well separated in rapidity. Our explic

E. Laenen, G. Schuler

We investigate the effects of photon radiation on deep-inelastic $\reγ$ scattering. Depending on the set of variables chosen, we find appreciable effects in the kinematic region accessible at LEP2. Convenient analytic results for $O(α)$ corrected differential cross sections are presented.

G. S. Bali, Ch. Schlichter, K. Schilling

We investigate -- as an alternative to usual Monte Carlo Renormalization Group methods -- the feasibility of extracting QCD beta-functions directly from a lattice analysis of correlations between the action and Wilson loops. We test this correlation technique numerically in four dimensional SU(2) gauge theory, on a 16^4 lattice at beta = 2.5 and find very pr

Lee Lindblom

The dynamics of the fluid fields in a large class of causal dissipative fluid theories is studied. It is shown that the physical fluid states in these theories must relax (on a time scale that is characteristic of the microscopic particle interactions) to ones that are essentially indistinguishable from the simple relativistic Navier-Stokes descriptions of t

Erik A. Martinez

The entropy of a quantum-statistical system which is classically approximated by a general stationary eternal black hole is studied by means of a microcanonical functional integral. This approach opens the possibility of including explicitly the internal degrees of freedom of a physical black hole in path integral descriptions of its thermodynamical properti

P. F. Gonzalez-Diaz

This paper deals with the geometry of supermassive cosmic strings. We have used an approach that enforces the spacetime of cosmic strings to also satisfy the conservation laws of a cylindric gravitational topological defect, that is a spacetime kink. In the simplest case of kink number unity, the entire energy range of supermassive strings becomes then quant

Luis Gonzalez-Mestres

Superluminal particles are not excluded by particle physics. The apparent Lorentz invariance of the laws of physics does not imply that space-time is indeed minkowskian. Matter made of solutions of Lorentz-invariant equations would feel a relativistic space-time even if the actual space-time had a quite different geometry (f.i. a galilean space-time). If Lor

M. Wintel, H. U. Everts, W. Apel

We have simulated the classical Heisenberg antiferromagnet on a triangular lattice using a local Monte Carlo algorithm. The behavior of the correlation length $ξ$, the susceptibility at the ordering wavevector $χ(\bf Q)$, and the spin stiffness $ρ$ clearly reflects the existence of two temperature regimes -- a high temperature regime $T > T_{th}$, in which t

J. M. Deutsch, Tanya Kurosky

We apply a new approach to the reverse protein folding problem. Our method uses a minimization function in the design process which is different from the energy function used for folding. For a lattice model, we show that this new approach produces sequences that are likely to fold into desired structures. Our method is a significant improvement over previou

B. Srinivas, Christine Doran, Seth Kulick

There are currently two philosophies for building grammars and parsers -- Statistically induced grammars and Wide-coverage grammars. One way to combine the strengths of both approaches is to have a wide-coverage grammar with a heuristic component which is domain independent but whose contribution is tuned to particular domains. In this paper, we discuss a th

Kavan U. Ratnatunga, Eric J. Ostrander, Richard E. Griffiths, Myungshin Im

We report the serendipitous discovery of ``Einstein cross&#39;&#39; gravitational lens candidates using the Hubble Space Telescope. We have so far discovered two good examples of such lenses, each in the form of four faint blue images located in a symmetric configuration around a red elliptical galaxy. The high resolution of HST has facilitated the discovery

D. Downes, P. M. Solomon, S. R. Radford

New observations with the IRAM interferometer of CO(3--2) from the highly luminous galaxy IRAS F10214+4724 show the source is 1.5&#39;&#39; x <= 0.9&#39;&#39; ; they display no evidence of any velocity gradient. This size, together with optical and IR data that show the galaxy is probably gravitationally lensed, lead to a new model for the CO distribution. I

Jan P. Mücket, Patrick Petitjean, Ronald E. Kates, Rüdiger Riediger

We study the evolution with redshift of the number density of Ly$α$ clouds in a CDM model using numerical simulations including photo-ionization and cooling of the baryonic component. The photo-ionizing flux is consistently taken as proportional to the rate at which material cools below 5000~K in the simulation. The number density of lines with $N$(HI)~$>$~1

K. Jahn, R. Schlichenmaier, H. U. Schmidt

The motion of an individual magnetic flux tube inside the penumbra of a sunspot is studied numerically. Here, we present preliminary results. The thin flux tube approximation together with a simplified radiative heat exchange with the surroundings is used to study the evolution of a flux tube embedded into a background given by a global magneto-static sunspo

M. A. Pahre, S. G. Djorgovski, R. R. de Carvalho

We present results from a near-infrared $K$-band imaging survey of 59 elliptical galaxies in five nearby clusters. We measure photometric parameters for each galaxy using surface photometry and draw velocity dispersions from the literature. Three observables define a near-infrared Fundamental Plane (FP) of elliptical galaxies with $R_e \propto σ^{1.44\pm0.04

Denis Uglov

The hierarchy of Integrable Spin Chain Hamiltonians, which are trigonometric analogs of the Haldane Shastry Model and of the associated higher conserved charges, is derived by a reduction from the trigonometric Dynamical Models of Bernard-Gaudin-Haldane-Pasquier. The Spin Chain Hamiltonians have the property of $U_q(\hat{gl}_2)$-invariance. The spectrum of t

E. L. Bratkovskaya, W. Cassing, U. Mosel, O. V. Teryaev

A full calculation of lepton-pair angular characteristics is carried out for $e^+e^-$ pairs created in $pp$, $pn$ and $pd$ collisions at intermediate energies. It is demonstrated that the proposed new observable, the dilepton decay anisotropy, quite sensitively changes for different sources and may be useful for their disentangling. The relevance of the dile

Tobias Hurth

An alternative approach to perturbative Yang-Mills theories in four (3+1) dimensional space-time based on the causal Epstein-Glaser method in QFT was recently proposed. In this short note we show that the set of identities between C-number distributions expressing nonabelian gauge invariance in the causal approach imply identities which are analogous to the

K. Kajantie, M. Laine, K. Rummukainen, M. Shaposhnikov

We formulate the rules for dimensional reduction of a generic finite temperature gauge theory to a simpler three-dimensional effective bosonic theory in terms of a matching of Green&#39;s functions in the full and the effective theory, and present a computation of a generic set of 1- and 2-loop graphs needed for the application of these rules. As a concrete

H. Fujisaki, K. Kumekawa, M. Yamaguchi, M. Yoshimura

Large amplitude oscillation of cosmic field that may occur right after inflation and in the decay process of weakly interacting fields gives rise to violent particle production via the parametric resonance. In the large amplitude limit the problem of back reaction against the field oscillation is solved and the energy spectrum of created particles is determi

K. Daikouji, M. Shino, Y. Sumino

We derive a full Bern-Kosower-type rule for scalar QED starting from quantum field theory: we derive a set of rules for calculating $S$-matrix elements for any processes at any order of the coupling constant. Gauge-invariant set of diagrams in general is first written in the worldline path-integral expression. Then we integrate over $x(τ)$, and the resulting

Guo-Hong Wu

Several aspects of the flavor-diagonal extended technicolor (ETC) gauge boson are reviewed. Among them are an increase of $R_b$ that could explain the LEP $R_b$ excess, a sizable, positive correction to the $τ$ asymmetry parameter $A_τ$, and a contribution to the weak-isospin breaking $ρ$ parameter that is just barely acceptable by present data.

George Kirczenow

Simple and quite general considerations are used to show that the results of d.c. transport experiments on macroscopic Hall bars are inconsistent with Hartree models in which a majority of the branches of single-particle composite fermion edge states at the Fermi level propagate in the direction opposite to that in which non-interacting electrons travel alon

Wayne Hu

We develop and examine the principles governing the formation of distortions in the cosmic microwave background. Distortions in the frequency or spectral distribution of the background probe the thermal history of the universe whereas those in the angular temperature distribution probe its dynamics and geometry. Stressing model independent results, we show h

Sun Hong Rhie

The total amplification of a source inside a caustic curve of a binary lens is no less than 3. Here we show that the infimum amplification 3 is satisfied by a family of binary lenses where the source position is at the mid-point between the lens positions independently of the mass ratio which parameterizes the family. We present a new proof of an underlying

S. Chattopadhayay

Using a recently developed method for the inclusion of fluctuation in the BUU dynamics, we study the self-consistent propagation of inherent thermal noise of unstable nuclear matter. The large time behaviour of the evolving system exhibits synergism between fluctuation and non-linearities in a universal manner which manifest in the appearance of macroscopic

S. Chaudhuri, D. A. Lowe

Using finite abelian automorphism groups of $K3$ we construct orbifold candidates for Type IIA-heterotic dual pairs with maximal supersymmetry in six and lower dimensions. On the heterotic side, these results extend the series of known reduced rank theories with maximal supersymmetry. The corresponding Type IIA theories generalize the Schwarz and Sen proposa

Masatoshi Sato

The relation between shapes of cosmic string and baryon number violation is investigated. If there exist fermionic zero modes on the string, using bosonization technique, it is possible to obtain the effective action which describes the fermion coupled to the arbitrarily shaped cosmic string. The relation between baryon number and the sum of the writhing num

O. V. Teryaev

The power correction, surviving the zero quark mass limit and found earlier to restore the validity of Burkhardt-Cottingham sum rule, provides the contribution to the Bjorken sum rule as well. The leading perturbative correction to the Bjorken sum rule is increased by the factor 4/3 for light quarks and 5/3 for heavy quarks. The resulting value for the Bjork

Leon Balents, Leo Radzihovsky

We use Ginzburg-Landau theory to study the $H_{c2}$ transition in layered superconductors with field parallel to the layers, finding a continuous 3d freezing transition to a triangular vortex super-solid in the three-dimensional XY universality class. If screening effects are neglected, off--diagonal--long--range--order survives only for $d>d_{lc}=5/2$. The

Diptiman Sen, B. Sriram Shastry, R. E. Walstedt, R. Cava

We study the sawtooth lattice of a coupled spin $1/2$ Heisenberg system, a variant of the railroad trestle lattice. The ground state of this system is two-fold degenerate with periodic boundary conditions and supports kink antikink excitations, which are distinct in this case, unlike the railroad trestle lattice. The resulting low temperature thermodynamics

A. Chaiken, R. P. Michel, C. -T. Wang

Fe/Si multilayers with antiferromagnetic interlayer coupling have been grown via ion-beam sputtering on both glass and single-crystal substrates. High-angle x-ray diffraction measurements show that both sets of films have narrow Fe peaks, implying a large crystallite size and crystalline iron silicide spacer layers. Low-angle x-ray diffraction measurements s

Francis Bernardeau, Rien van de Weygaert

We introduce two new methods to obtain reliable velocity field statistics from N-body simulations, or indeed from any general density and velocity fluctuation field sampled by discrete points. These methods, the {\it Voronoi tessellation method} and {\it Delaunay tessellation method}, are based on the use of the Voronoi and Delaunay tessellations of the poin

T. Padmanabhan

The gravitational clustering of collisionless particles in an expanding universe is modelled using some simple physical ideas. I show that it is indeed possible to understand the nonlinear clustering in terms of three well defined regimes: (1) linear regime (2) quasilinear regime which is dominated by scale-invariant radial infall and (3) nonlinear regime do

John H. Schwarz

An SL(2, Z) family of string solutions of type IIB supergravity in ten dimensions is constructed. The solutions are labeled by a pair of relatively prime integers, which characterize charges of the three-form field strengths. The string tensions depend on these charges in an SL(2, Z) covariant way. Compactifying on a circle and identifying with eleven-dimens

V. M. Ter--Antonyan, A. Nersessian

It is shown that $U(1)$--Hamiltonian reduction of a four--dimensional isotropic quantum oscillator results in a bound system of two spinless Schwinger&#39;s dyons. Its wavefunctions and spectrum are constructed.

M. T. Grisaru, M. E. Wehlau

In the framework of the prepotential description of superspace two-dimensional $(2,2)$ supergravity, we discuss the construction of invariant integrals. In addition to the full superspace measure, we derive the measure for chiral superspace, and obtain the explicit expressions for going from superspace actions to component actions. We consider both the minim

Eric Braaten, Yu-Qi Chen

The inclusive cross section for the production of $J/ψ$ in $e^+ e^-$ annihilation is studied using a recently developed factorization formalism. In addition to the conventional color-singlet contribution, we include contributions from $c \bar c$ pairs that are produced at short distances in color-octet states. The color-octet contributions are suppressed by

V. N. Pervushin, G. Roepke, M. K. Volkov, D. Blaschke

The problem of the gluonic quasiparticle excitations in QCD is considered under the aspect of the condensation of gluon pairs in the &#39;&#39;squeezed&#39;&#39; vacuum. The present approach is a field theoretical generalization of the Bogoliubov model which successfully reproduced the Landau spectrum in the microscopic theory of superfluidity. We construct

Somenath Chakrabarty

The expulsion of magnetic flux lines from a growing superconducting core of a quark star has been investigated. The idea of impurity diffusion in molten alloys and an identical mechanism of baryon number transport from hot quark-gluon-plasma phase to hadronic phase during quark-hadron phase transition in the early universe, micro-second after big bang has be

Yoshio Koide

On the basis of a seesaw-type mass matrix model for quarks and leptons, $M_f \simeq m_L M_F^{-1} m_R$, where $m_L\propto m_R$ are universal for $f=u,d,ν$ and $e$ (up-quark-, down-quark-, neutrino- and charged lepton-sectors), and $M_F$ is given by $M_F=K ({\bf 1} + 3 b_f X)$ ({\bf 1} is a $3\times 3$ unit matrix, $X$ is a democratic-type matrix and $b_f$ is

J. W. van Holten

Path-integral expressions for one-particle propagators in scalar and fermionic field theories are derived, for arbitrary mass. This establishes a direct connection between field theory and specific classical point-particle models. The role of world-line reparametrization invariance of the classical action and the implementation of the corresponding BRST-symm

R. Montagne, E. Hernandez-Garcia, M. San Miguel

We numerically study in the one-dimensional case the validity of the functional calculated by Graham and coworkers as a Lyapunov potential for the Complex Ginzburg-Landau equation. In non-chaotic regions of parameter space the functional decreases monotonically in time towards the plane wave attractors, as expected for a Lyapunov functional, provided that no

Gabriel Kotliar, Qimiao Si

We study the mixed valence regime of a generalized Anderson impurity model using the bosonization approach. This single impurity problem is defined by the $U=\infty$ Anderson model with an additional density-density interaction, as well as an explicit exchange interaction, between the impurity and conduction electrons. We find three points in the interaction

Nemanja Kaloper

Different compactifications of six-dimensional string theory on $M_4 \times T^2$ are considered. Particular attention is given to the roles of the reduced modes as the $S$ and $T$ fields. It is shown that there is a discrete group of invariances of an equilateral triangle hidden in the model. This group is realized as the interchanges of the two-form fields

Angel Rubio, Yoshiyuki Miyamoto, X. Blase, Marvin L. Cohen

Using first-principles total-energy pseudopotential calculations, we have studied the properties of chains of potassium and aluminum in nanotubes. For BN tubes, there is little interaction between the metal chains and the tubes, and the conductivity of these tubes is through carriers located at the inner part of the tube. In contrast, for small radius carbon

I. Sachs, A. Wipf

The Thirring model and various generalizations of it are analyzed in detail. The four-Fermi interaction modifies the equation of state. Chemical potentials and twisted boundary conditions both result in complex fermionic determinants which are analyzed. The non-minimal coupling to gravity does deform the conformal algebra which in particular contains the min