April 1997 arXiv papers

J. Alexander, B. Balick

The errors inherent to the use of the standard "ionization correction factor" ("i_CF") method of calculating nebular conditions and relative abundances of H, He, N, O, Ne, S, and Ar in emission line nebulae have been investigated under conditions typical for planetary nebulae. The photoionization code CLOUDY was used to construct a series of

Z. W. Lu, B. M. Klein

We demonstrate that elastic anomalies and lattice instabilities in the the A15 compounds are describable in terms of first-principles LDA electronic structure calculations. We show that at T=0 V_3Si, V_3Ge, and Nb_3Sn are intrinsically unstable against shears with elastic moduli C_11-C_12 and C_44, and that the zone center phonons, Gamma_2 and Gamma_12, are

E. V. Shuryak

The event-by-event analysis of heavy ions collisions is becoming possible with advent of large acceptance detectors: it can provide dynamical information which cannot be obtained from inclusive spectra. We identify some observables which can be related to standard thermodynamical fluctuations and therefore may provide information about properties of hadronic

E. Keith, Ernest Ma

We consider an arbitrary supersymmetric U(1) gauge factor at the TeV scale, under which the two Higgs superfields H_{1,2} of the standard model are nontrivial. We assume that there is a singlet superfield S such that H_1 H_2 S is an allowed term in the superpotential. We discuss first the generic consequences of this hypothesis on the structure of the two-do

Lev Kofman, Andrei Linde, Alexei Starobinsky

Reheating after inflation occurs due to particle production by the oscillating inflaton field. In this paper we describe the perturbative approach to reheating, and then concentrate on effects beyond the perturbation theory. They are related to the stage of parametric resonance called preheating. It may occur in an expanding universe if the initial amplitude

P. Braun-Munzinger, D. Miskowiec, A. Drees, C. Lourenco

Measurements of open charm hadro-production from CERN and Fermilab experiments are reviewed, with particular emphasis on the absolute cross sections and on their A and sqrt(s) dependences. Differential pt and xf cross sections calculated with the Pythia event generator are found to be in reasonable agreement with recent data. The calculations are scaled to n

G. L. Kane, Gregory Mahlon

There is a class of supersymmetric models which is well-motivated by hints of evidence for SUSY and consistent with all existing data. It is important to study the predictions of these models. They are characterized by M(N3) > M(C1) > M(snu) > M(N1) (where Ni and Ci are neutralino and chargino mass eigenstates), |mu| ~< M1 ~< M2 ~= M(Z), mu < 0, and tan(beta

Walter Kunhardt

In the DHR theory of superselection sectors, one usually considers states which are local excitations of some vacuum state. Here, we extend this analysis to local excitations of a class of &#34;infravacuum&#34; states appearing in models with massless particles. We show that the corresponding superselection structure, the statistics of superselection sectors

P. Andersson, A. De Min, J. J. Hernandez, K. Hultqvist

The hep-ex data base was decided not to be an appropriate place to make DELPHI notes public. Sorry for the inconvenience.

S. Dalley

The small momentum fraction x behaviour of quarks in mesons is analysed in the 1+1-dimensional reduced model of large-N QCD by light-cone quantisation.

M. N. Chernodub, F. V. Gubarev, M. I. Polikarpov

We study a field-theoretical analogue of the Aharonov-Bohm effect in two-, three- and four-dimensional Abelian Higgs models; the corresponding topological interaction is proportional to the linking number of the Abrikosov vortex and the particle world trajectories. We show that the Aharonov-Bohm effect gives rise to a nontrivial interaction of charged test p

Jens Eggers

A slender-jet model for the pinching of a liquid column is considered in the limit of vanishing viscosity. We find the model to develop a singularity in the gradients of the local radius and the velocity at a finite thread radius, so it does not describe breakup. However, the observed steepening of the profile corresponds to experiments and simulations with

Igor Batalin, Robert Marnelius

A general field-antifield BV formalism for antisymplectic first class constraints is proposed. It is as general as the corresponding symplectic BFV-BRST formulation and it is demonstrated to be consistent with a previously proposed formalism for antisymplectic second class constraints through a generalized conversion to corresponding first class constraints.

G. Kälbermann

We present a numerical simulation of the scattering of a topological soliton off finite size attractive impurities, repulsive impurities and a combination of both. The attractive and attractive-repulsive cases show similar features to those found for $δ$ function type of impurities. For the repulsive case, corresponding to a finite width barrier, the soliton

B. Guberina, B. Melic

We have quantitatively reanalyzed the inclusive charmed-baryon decays. New ingredients are the Voloshin preasymptotic effects in semileptonic decays and the Cabibbo-subleading contributions to both semileptonic and nonleptonic decays. It has been found that the Cabbibo-subleading Voloshin contribution essentially improves the theoretical semileptonic branchi

D. Drechsel, G. Knoechlein, A. Yu. Korchin, A. Metz

We analyze virtual Compton scattering off the nucleon at low energies in a covariant, model-independent formalism. We define a set of invariant functions which, once the irregular nucleon pole terms have been subtracted in a gauge-invariant fashion, is free of poles and kinematical zeros. The covariant treatment naturally allows one to implement the constrai

Radu Tatar

We study brane configurations which correspond to N=1 field theories in four dimensions. By inverting the order of the NS 5-branes and D6-branes, a check on dualities in four dimensional theories can be made. We consider a brane configuration which yields electric/magnetic duality for gauge theories with $SO(N_{c1})\times Sp(N_{c2})$ product gauge group. We

Ricardo Schiappa

We introduce new local gauge invariant variables for N=1 supersymmetric Yang-Mills theory, explicitly parameterizing the physical Hilbert space of the theory. We show that these gauge invariant variables have a geometrical interpretation, and can be constructed such that the emergent geometry is that of N=1 supergravity: a Riemannian geometry with vector-spi

Werner Fischer, Thomas Hupfer, Hajo Leschke, Peter Mueller

Schroedinger operators with certain Gaussian random potentials in multi-dimensional Euclidean space possess almost surely an absolutely continuous integrated density of states and no absolutely continuous spectrum at sufficiently low energies.

Creon Levit, Jack Sarfatti

The de Broglie-Bohm ontological interpretation of quantum theory clarifies the understanding of many otherwise counter-intuitive quantum mechanical phenomena. We report here on an application of Bohm&#39;s quantum potential to the bonding and reactivity of small molecules. In the field of quantum chemistry, Bader has shown that the topology of the Laplacian

M. Bleicher, S. A. Bass, M. Belkacem, J. Brachmann

Microscopic calculations of central collisions between heavy nuclei are used to study fragment production and the creation of collective flow. It is shown that the final phase space distributions are compatible with the expectations from a thermally equilibrated source, which in addition exhibits a collective transverse expansion. However, the microscopic an

Andrei Zelevinsky

This note is an extended abstract of my talk at the workshop on Representation Theory and Symmetric Functions, MSRI, April 14, 1997. We discuss the problem of finding an explicit description of the semigroup $LR_r$ of triples of partitions of length $\leq r$ such that the corresponding Littlewood-Richardson coefficient is non-zero. After discussing the histo

Kang-Tae Kim, Mario Landucci, Andrea F. Spiro

In this article, we consider a bounded pseudoconvex domain in ${\bf C}^2$ satifying: (a) it admits a proper holomorphic mapping $f$ onto the unit ball $B^2$, and (b) it is simply connected and has a real analytic boundary. According to [Barletta-Bedford, Indiana U. Math. J, 39(1985), 315-338], the strong pseudconvexity of $B^2$ alone yields that such a domai

Uwe Trittmann, Hans-Christian Pauli

Front form dynamics is not a manifestly rotational invariant formalism. In particular, the requirement of an invariance under rotations around the transverse axes is difficult to fulfill.In the present work it is investigated, to which extent rotational invariance is restored in the solution of a light-cone quantized field theory. The positronium spectrum in

I. L. Buchbinder, E. I. Buchbinder, S. M. Kuzenko, B. A. Ovrut

The background field method for N=2 super Yang-Mills theories in harmonic superspace is developed. The ghost structure of the theory is investigated. It is shown that the ghosts include two fermionic real omega-hypermultiplets (Faddeev-Popov ghosts) and one bosonic real omega-hypermultiplet (Nielsen-Kallosh ghost), all in the adjoint representation of the ga

S. Lukyanov

A free field representation for form-factors of exponential operators in the affine A^{(1)}_{N-1} Toda model is proposed. The one and two particle form-factors are calculated explicitly.

Brandon Carter

To facilitate the treatment of electromagnetic effects in applications such as dynamically perturbed vortons, this work employs a covariantly formulated string-source Green measure to obtain a coherent relativistic scheme for describing the self interaction of electromagnetic currents in string models of a very general kind, at leading order in the relevant

Petre Diţă

We develop here a simple formalism that converts the second-class constraints into first-class ones for a particle moving on the $n$-dimensional sphere. The Poisson algebra generated by the Hamiltonian and the constraints closes and by quantization transforms into a Lie algebra. The observable of the theory is given by the Casimir operator of this algebra an

Howard Baer, Chih-hao Chen, Manuel Drees, Frank Paige

If the parameter $tan β$ of the minimal supersymmetric model is large, then $b$ and $τ$ Yukawa interactions are important. These can significantly modify the masses and decays of sparticles. We describe new calculations which allow a reliable exploration of large $tan β$ values, and discuss implications for collider experiments. For large values of $tan β$,

Estia Eichten, Kenneth Lane, John Womersley

In multiscale and topcolor-assisted models of walking technicolor, relatively light spin-one technihadrons $ρ_T$ and $ω_T$ exist and are expected to decay as $ρ_T \to W π_T, Z π_T$ and $ω_T \to γπ_T$. For $M_{ρ_T} \simeq 200 GeV$ and $M_{π_T} \simeq 100 GeV$, these processes have cross sections in the picobarn range in $\bar p p$ colisions at the Tevatron an

K. Goulianos

We explore the theoretical and experimental consequences of a model proposed by Samim Erhan and Peter Schlein for unitarizing the diffractive amplitude by damping the pomeron flux at small x-pomeron and conclude that the model is unphysical and contradicts well established experimental data.

A. Pich

The pure leptonic or semileptonic character of tau decays makes them a good laboratory to test the structure of the weak currents and the universality of their couplings to the gauge bosons. The hadronic tau decay modes constitute an ideal tool for studying low-energy effects of the strong interactions in very clean conditions; a well-known example is the pr

E. V. Shuryak

This talk consists of two very different parts: the first one deals with non-perturbative QCD and physics of the chiral restoration, the second with rather low-key (and still unfinished) work aiming at obtaining EOS and other properties of hot/dense hadronic matter from data on heavy ion collisions. The microscopic mechanism for chiral restoration phase tran

E. V. Shuryak

CERN dilepton experiments have provided the most exciting data. Strong enhancement at low masses observed by CERES and HELIOS3 indicate strong modification in the vector channel in matter compared to vacuum properties. NA50 data on $J/ψ$ suppression in PbPb collisions show surprising deviation from the previous trend. The question is whether it is the expect

A. Djouadi, J. Kalinowski, M. Spira

We describe the Fortran code HDECAY which calculates the decay widths and the branching ratios of the Standard Model Higgs boson, and of the neutral and charged Higgs particles of the Minimal Supersymmetric extension of the Standard Model. The program is self-contained (with all subroutines included), easy to run, fast and calculates the decay widths and bra

L. Bourhis, M. Fontannaz, J. Ph. Guillet

The fragmentation functions of quarks and gluons into photons are studied beyond the Leading Logarithm approximation. We address the nature of the initial conditions of the evolution equation solutions and study problems related to factorization scheme invariance. The possibility of measuring these distributions in LEP experiments is discussed, and a compari

She-Sheng Xue

In this article we discuss the problem of the extreme fine-tuning necessary to achieve the top quark mass scale $m_t$ within the dynamical symmetry breaking of the phenomenological $t \bar t$ condensate model. Inspired by the vector-like phenomenon of chiral gauge theories at short distances, we postulate that the $W^\pm$-gauge bosons possess a vector-like g

F. Ferrer, J. A. Grifols

We reexamine the limits on the gravitino mass supplied by the muon anomaly in the frame of supergravity models with a superlight gravitino and a superlight scalar S and a superlight pseudoscalar P.

M. Caffo, H. Czyz, E. Remiddi

We present the Monte Carlo program BHAGEN95, for calculating the cross-section of the Bhabha scattering process at LEP1/SLC and LEP2 energies, usable with continuity from small to large-angle configurations. We discuss some improvements in the event generator BHAGEN94, which is now part of the new code. In particular the weak and QCD corrections are implemen

D. P. Roy

The top quark data in the lepton plus $τ$ channel offers a viable probe for the charged Higgs boson signal. We have analysed the recent Collider Detector at Fermilab (CDF) data in this channel to obtain a significant limit on the $H^\pm$ mass in the large $\tanβ$ region.

D. A. Johnston, P. Plechac

We investigate numerically and analytically Potts models on ``thin&#39;&#39; random graphs -- generic Feynman diagrams, using the idea that such models may be expressed as the N --> 1 limit of a matrix model. The thin random graphs in this limit are locally tree-like, in distinction to the ``fat&#39;&#39; random graphs that appear in the planar Feynman diagr

D. Glenzinski

In 1996, after another set of upgrades, LEP began running for the first time at center-of-mass energies above the W-pair production threshold. This new energy regime is rich in physics and offers new tests of the Standard Model, increased sensitivity for search physics, and precision W physics. We summarize the recent results from OPAL using 9.9 pb^-1 of dat

J. Cruz, J. Navarro-Salas, M. Navarro, C. F. Talavera

We study the evaporation process of a 2D black hole in thermal equilibrium when the ingoing radiation is switched off suddenly. We also introduce global symmetries of generic 2D dilaton gravity models which generalize the extra symmetry of the CGHS model.

Ichiro Oda

We study the Hawking radiation in two dimensional dilaton black hole by means of quantum gravity holding near the apparent horizon. First of all, we construct the canonical formalism of the dilaton gravity in two dimensions. Then the Vaidya metric corresponding to the dilaton black hole is established where it is shown that the dilaton field takes a form of

Francis Bonahon

In 3-dimensional hyperbolic geometry, the classical Schlafli formula expresses the variation of the volume of a hyperbolic polyhedron in terms of the length of its edges and of the variation of its dihedral angles. We prove a similar formula for the variation of the volume of the convex core of a geometrically finite hyperbolic 3--manifold M, as we vary the

Francis Bonahon

A fundamental object in a hyperbolic 3-manifold M is its convex core C(M), defined as the smallest closed non-empty convex subset of M. We investigate the way the geometry of the boundary S of C(M) varies as we vary the hyperbolic metric of M. Thurston observed that the intrinsic metric of S is hyperbolic, and that its bending is described by a measured geod

Karl-Heinz Wagenblast, Anne van Otterlo, Gerd Schoen, Gergely T. Zimanyi

We study the influence of a tunable dissipative environment on the dynamics of Josephson junction arrays near the superconductor-insulator transition. The experimental realization of the environment is a two dimensional electron gas coupled capacitively to the array. This setup allows for the well-controlled tuning of the dissipation by changing the resistan

Gene F. Mazenko, Robert A. Wickham

We show how the continuity equations expressing conservation of topological point or string defect charge can be used to determine the order-parameter correlation function for the phase-ordering kinetics of the O(n) model in the special case where the order parameter is constrained to be near a defect core. In this regime we find a self-consistent solution b

Dragana Popovic, A. B. Fowler, S. Washburn

We report the observation of a metal-insulator transition in a two-dimensional electron gas in silicon. By applying substrate bias, we have varied the mobility of our samples, and observed the creation of the metallic phase when the mobility was high enough ($μ~> 1 m^2/Vs$), consistent with the assertion that this transition is driven by electron-electron in

Alexandre M. Zagoskin, Ian Affleck

Fermi edge adsorption singularities (FES) are studied using a combination of conformal field theory (CFT), an exact sum rule and numerical work on a tight binding model which is shown to exhibit remarkable simplifying features. The relationship between FES and Anderson orthogonality exponent is established in great generality, using CFT, including the case w

P. Ao, X. -M. Zhu

We outline a conventional path integral derivation of the transverse force and the friction for a vortex in a superconductor based on the BCS theory. The derivation is valid in both clean and dirty limits at both zero and finite temperatures. The transverse force is found to be precisely as what has been obtained by Ao and Thouless using the Berry&#39;s phas

Giuliano Benenti, Giulio Casati, Dima L. Shepelyansky

We present analytical and numerical results for the microwave excitation of nonhydrogenic atoms in a static electric field when up to 1000 photons are required to ionize an atom. For small microwave fields, dynamical localization in photon number leads to exponentially small ionization while above quantum delocalization border ionization goes in a diffusive

D. Schmeltzer, E. Kogan, R. Berkovits, M. Kaveh

We present a theoretical analysis of the recent experimental results of Thomas et al on transport properties of spin polarized quantum wires. We suggest an explanation of the observed deviations of the conductance from the universal value $G=2e^2/h$ per channel in the wire. We argue that the new quasi plateau observed for the conductance at the value $G=1.4e

Ido Golding, Yacov Kantor

We use complete enumeration and Monte Carlo techniques to study two-dimensional self-avoiding polymer chains with quenched ``charges&#39;&#39; $\pm 1$. The interaction of charges at neighboring lattice sites is described by $q_i q_j$. We find that a polymer undergoes a collapse transition at a temperature $T_θ$, which decreases with increasing imbalance betw

Udo Hahn, Michael Strube

We specify an algorithm that builds up a hierarchy of referential discourse segments from local centering data. The spatial extension and nesting of these discourse segments constrain the reachability of potential antecedents of an anaphoric expression beyond the local level of adjacent center pairs. Thus, the centering model is scaled up to the level of the

H. Giacomini, S. Neukirch

In this paper, we study a Lienard system of the form dot{x}=y-F(x), dot{y}=-x, where F(x) is an odd polynomial. We introduce a method that gives a sequence of algebraic approximations to the equation of each limit cycle of the system. This sequence seems to converge to the exact equation of each limit cycle. We obtain also a sequence of polynomials R_n(x) wh

Boris Chirikov

A new generic dynamical phenomenon of pseudochaos and its relevance to the statistical physics both modern as well as traditional one are considered and explained in some detail. The pseudochaos is defined as a statistical behavior of the dynamical system with discrete energy and/or frequency spectrum. In turn, the statistical behavior is understood as time-

Boris Chirikov

Interrelations between dynamical and statistical laws in physics, on the one hand, and between the classical and quantum mechanics, on the other hand, are discussed with emphasis on the new phenomenon of dynamical chaos. The principal results of the studies into chaos in classical mechanics are presented in some detail, including the strong local instability

Chao Xu, A. J. Roberts

We develop further ideas on how to construct low-dimensional models of stochastic dynamical systems. The aim is to derive a consistent and accurate model from the originally high-dimensional system. This is done with the support of centre manifold theory and techniques. Aspects of several previous approaches are combined and extended: adiabatic elimination h

R. O. Grigoriev, M. C. Cross, H. G. Schuster

Linear control theory is used to develop an improved localized control scheme for spatially extended chaotic systems, which is applied to a Coupled Map Lattice as an example. The optimal arrangement of the control sites is shown to depend on the symmetry properties of the system, while their minimal density depends on the strength of noise in the system. The

J. W. Moffat

Cosmological consequences of the nonsymmetric gravitational theory (NGT) are studied. The structure of the NGT field equations is analyzed for an inhomogeneous and anisotropic universe, based on the spherically symmetric field equations. It is assumed that the matter density and pressure are purely time dependent, and it is shown that the field equations all

Lowell S. Brown, R. F. Sawyer

We consider the electron density at the position of an ion of charge Ze in a plasma under conditions approximating those in the core of the sun. Numerical calculations have shown that the plasma effects on the density, over and above the ordinary Coulomb factors that are obtained in the absence of electron-electron interactions, are well represented by a red

Theodore P. Stecher, Robert H. Cornett, Michael R. Greason, Wayne B. Landsman

The Ultraviolet Imaging Telescope (UIT) was flown as part of the Astro observatory on the Space Shuttle Columbia in December 1990 and again on the Space Shuttle Endeavor in March 1995. Ultraviolet (1200-3300 Angstroms) images of a variety of astronomical objects, with a 40 arcmin field of view and a resolution of about 3 arcsec, were recorded on photographic

E. Vazquez-Semadeni, T. Passot, A. Pouquet

We investigate the properties of highly compressible turbulence and its ability to produce self-gravitating structures. The compressibility is parameterized by an effective polytropic exponent gama-eff. In the limit of small gama-eff, the density jump at shocks is shown to be of the order of e^{M^2}, and the production of vorticity by the nonlinear terms app

K. Weis, Y. -H. Chu, W. J. Duschl, D. J. Bomans

Ring nebulae are often found around massive stars such as Wolf-Rayet stars, OB and Of stars and Luminous Blue Variables (LBVs). In this paper we report on two ring nebulae around blue supergiants in the Large Magellanic Cloud. The star Sk-69 279 is classified as O9f and is surrounded by a closed shell with a diameter of 4.5 pc. Our echelle observations show

James Dunlop

I briefly review our current knowledge of the cosmological evolution of radio sources, and show that the redshift distributions of new complete samples of radio sources confirm the existence of the high-redshift decline in comoving number density (or `cutoff&#39;) beyond $z \simeq 2.5$ first deduced by Dunlop & Peacock (1990). Taken at face value these new d

Donald C. Ellison, L. O&#39;C. Drury, Jean-Paul Meyer

This is the second paper (the first was astro-ph/9704267) of a series analysing the Galactic Cosmic Ray (GCR) composition and origin. In this we present a quantitative model of GCR origin and acceleration based on the acceleration of a mixture of interstellar and/or circumstellar gas and dust by supernova remnant blast waves. We present results from a nonlin

T. Shahbaz, M. Livio, K. A. Southwell, P. A. Charles

We present the first observational evidence for a collimated jet in a cataclysmic variable system; the recurrent nova T Pyxidis. Optical spectra show bipolar components of H$α$ with velocities $\sim 1400 km/s$, very similar to those observed in the supersoft X-ray sources and in SS 433. We argue that a key ingredient of the formation of jets in the supersoft

E. Giallongo, A. Fontana, P. Madau

We use new studies of the cosmic evolution of star-forming galaxies to estimate the production rate of ionizing photons from hot, massive stars at low and intermediate redshifts. The luminosity function of blue galaxies in the Canada-France Redshift Survey shows appreciable evolution in the redshift interval z=0-1.3, and generates a background intensity at 1

Abraham Loeb

The transition between the nearly smooth initial state of the Universe and its clumpy state today occurred during the epoch when the first stars and low-luminosity quasars formed. For Cold Dark Matter cosmologies, the radiation produced by the first baryonic objects is expected to ionize the Universe at z=10-20 and consequently suppress by 10% the amplitude

S. P. Goodwin, J. Gribbin, M. A. Hendry

Measurements of the linear diameters of 12 nearby spiral galaxies with distances determined from primary indicators suggest that both the Milky Way Galaxy and M31 are in the middle of the range of sizes for such galaxies. By comparing the measured linear diameters of these nearby systems with the inferred diameters of a sample of more than 3000 spirals with

M. C. Forbes, R. J. Dodd, D. J. Sullivan

This paper is the fourth in a series on the extension of the Vilnius photometric system to the southern hemisphere. Observations were made of 60 stars in the Harvard Standard E regions to increase a set of standard stars.

E. Bougleux, D. Galli

We examine the processes of formation and destruction of LiH molecules in the primordial gas at temperatures T \leq 5000 K in the framework of standard Friedmann cosmological models and we compute the optical depth of the Universe due to Thomson scattering of cosmic background photons on LiH. With the help of a simple model of evolution of a spherical densit

Alexander A. Voronov

The purpose of this paper is to suggest the construction and study properties of semi-infinite induction, which relates to semi-infinite cohomology the same way induction relates to homology and coinduction to cohomology. We prove a version of the Shapiro Lemma, relating the semi-infinite cohomology of a module with that of the semi-infinitely induced module

J. P. Leahy

Nodland and Ralston (astro-ph/9704196) claim evidence for a wavelength-independent cosmic birefringence. Although it has been shown (astro-ph/9704247, astro-ph/9704263) that the data analysed did not support this conclusion, the possibility of such an effect remains interesting. Here I present a much more accurate test using high-resolution radio images of d

Claudio Bartocci, Ugo Bruzzo, Daniel Hernandez Ruiperez, Jose&#39; M. Mu~noz Porras

We use a relative Fourier-Mukai transform on elliptic K3 surfaces $X$ to describe mirror symmetry. The action of this Fourier-Mukai transform on the cohomology ring of $X$ reproduces relative T-duality and provides an infinitesimal isometry of the moduli space of algebraic structures on $X$ which, in view of the triviality of the quantum cohomology of K3 sur

L. Bonora, S. Krivonos

A manifestly N=2 supersymmetric coset formalism is applied to analyse the &#34;fermionic&#34; extensions of N=2 $a=4$ and $a=-2$ KdV hierarchies. Both these hierarchies can be obtained from a manifest N=2 coset construction. This coset is defined as the quotient of some local but non-linear superalgebra by a $\hat{U(1)}$ subalgebra. Three superextensions of

Roberto Emparan

The recently proposed ``correspondence principle&#39;&#39; of Horowitz and Polchinski provides a concrete means to relate (among others) black holes with electric NS-NS charges to fundamental strings and correctly match their entropies. We test further this correspondence by examining the greybody factors in the absorption rates of neutral, minimally coupled

J. M. Robin

We compute exactly both the spectral function of the electron and of the small polaron for the two site Holstein model. We find that for intermediary coupling, the small polaron is a better fundamental excitation of the system than the electron. However, the Lang-Firsov approximation fails to predict the right dispersion relation for the small polaron.

P. Mitra

After summarizing the development of black hole thermodynamics in the seventies, we describe a recent microscopic model. This model suggests that the Bekenstein-Hawking area formula holds for extremal black holes as well as for ordinary (non-extremal) ones. On the other hand, semiclassical studies have suggested a discontinuity between non-extremal and extre

Mikhail Zotov

Recently E. E. Donets, D. V. Galtsov, and the author reported the results of numerical and analytical investigation of the SU(2) Einstein-Yang-Mills black hole interior solutions (gr-qc/9612067). It was shown that a generic interior solution develops a new type of an infinitely oscillating behavior with exponentially growing amplitude. Numerical data for thr

H. W. Lee, Y. S. Myung, Jin Young Kim

We perform the perturbation analysis of the black holes in the 4D, N=4 supergravity. Analysis around the black holes reveals a complicated mixing between the dilaton and other fields (metric and two U(1) Maxwell fields). It turns out that considering both s-wave (l=0) and higher momentum modes (l \neq 0), the dilaton as a fixed scalar is the only propagating

Jørgen Ellegaard Andersen, Josef Mattes

We show the existence of a universal Vassiliev invariant for links in closed surface cylinders by explicit construction using configuration space integrals.

Caroline H. Thompson

Re-evaluation of the evidence (some of it unpublished) shows that experimenters conducting Einstein-Podolsky-Bohm (EPR) experiments may have been deceived by various pre-conceptions and artifacts. False or unproven assumptions were made regarding, in some cases, fair sampling, in others timing, accidental coincidences and enhancement. Realist possibilities,

G. Giacomin, J. L. Lebowitz

We study properties of the solutions of a family of second order integro-differential equations, which describe the large scale dynamics of a class of microscopic phase segregation models with particle conserving dynamics. We first establish existence and uniqueness as well as some properties of the instantonic solutions. Then we concentrate on formal asympt

Eric Babson, Dmitry Kozlov

In this paper we study the problem of determining the homology groups of a quotient of a topological space by an action of a group. The method is to represent the original topological space as a homotopy limit of a diagram, and then act with the group on that diagram. Once it is possible to understand what the action of the group on every space in the diagra

Frank K. Hwang, Shmuel Onn, Uriel G. Rothblum

We consider the {\em Shaped Partition Problem} of partitioning $n$ given vectors in real $k$-space into $p$ parts so as to maximize an arbitrary objective function which is convex on the sum of vectors in each part, subject to arbitrary constraints on the number of elements in each part. In addressing this problem, we study the {\em Shaped Partition Polytope

A. Pashnev

It is shown that vielbeins and connections of any (super)space are naturally described in terms of nonlinear realizations of infinite - dimensional diffeomorphism groups of the corresponding (super)space. The method of construction of integral invariants from the invariant Cartan&#39;s differential $Ω$ - forms is generalized to the case of superspace.

Tim R. Morris, Michael D. Turner

We apply a derivative expansion to the Legendre effective action flow equations of O(N) symmetric scalar field theory, making no other approximation. We calculate the critical exponents eta, nu, and omega at the both the leading and second order of the expansion, associated to the three dimensional Wilson-Fisher fixed points, at various values of N. In addit

E. Atzmon

Measuring distances on a lattice in noncommutative geometry involves square, symmetric and real ``three-diagonal&#39;&#39; matrices, with the sum of their elements obeying a supremum condition, together with a constraint forcing the absolute value of the maximal eigenvalue to be equal to 1. In even dimensions, these matrices are unipotent of order two, while

L. Burakovsky, T. Goldman, L. P. Horwitz

By assuming the existence of (quasi)-linear Regge trajectories for heavy quarkonia in the low energy region, we derive a new, sixth power, meson mass relation which shows good agreement with experiment for both charmed and beauty mesons. This relation may be reduced to a quadratic Gell-Mann-Okubo type formula by fitting the values of the Regge slopes of thes

T. Li, J. Lopez, D. Nanopoulos

We show that the gravitino contribution to (g-2)_μ is finite in many popular supergravity models, including no-scale supergravity and string and M-theory models. This contribution is greatly enhanced for very light gravitino masses, and leads to new upper bounds on the ratio of the smuon to the gravitino mass.

Y. Hama, T. Kodama, Samya Paiva

We investigate several fluctuation effects in high-energy hadronic and nuclear collisions through the analysis of different observables. To introduce fluctuations in the initial stage of collisions, we use the Interacting Gluon Model (IGM) modified by the inclusion of the impact parameter. The inelasticity and leading-particle distributions follow directly f

Ignacio Bediaga, Carla Gobel, Ramon Mendez-Galain

We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the $D^+\to \bar{K}^0π^+π^0$ decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant ch

R. Harlander, M. Steinhauser

Three-loop corrections to the scalar and pseudo-scalar current correlator are calculated. By applying the large momentum expansion mass terms up to order (m^2/q^2)^4 are evaluated analytically. As an application O(α_s^2) corrections to the decay of a scalar and pseudo-scalar Higgs boson into top quarks are considered. It is shown that for a Higgs mass not fa

A. G. Oganesian

The method of estimation of the unknown high-dimensional vacuum averages is offered. This method is based on the idea of self-consistence of the factorization hypothesis. So it appears possible to evaluate all vacuum averages of dimension 7 and also get some estimations for vacuum averages of dimension 10. Obtained results are used to calculate high dimensio

Eric S. Swanson, Adam P. Szczepaniak

The heavy quark expansion of Quantum Chromodynamics and the strong coupling flux tube picture of nonperturbative glue are employed to develop the phenomenology of hybrid meson decays. The decay mechanism explicitly couples gluonic degrees of freedom to the pair produced quarks and hence does not obey the well known, but model-dependent, selection rule which

I. H. Duru

An interference experiment in a magnetic field free region with non vanishing vector potential created by two perpendicularly intersecting planes carrying uniform currents is discussed. The relation of this configuration to the Aharonov-Bohm potential is examined. An experimental set up which is finite in the direction of the electronic motion is studied.

L. Burakovsky, T. Goldman, L. P. Horwitz

By assuming the existence of (quasi)-linear Regge trajectories for 25-plet mesons in the low energy region, we derive a new, 14th power, meson mass relation. This relation may be reduced to a quadratic Gell-Mann-Okubo type formula by fitting the values of the Regge slopes of these (quasi)-linear trajectories. Such a formula holds with an accuracy of ~2% for

Kari Enqvist, John McDonald

We consider the question of whether cosmic ray catalysed false vacuum decay can be phenomenologically more important than spontaneous decay via quantum tunnelling. We extend the zero bubble wall width Landau-WKB analysis of catalysed false vacuum decay to include the leading order effects of finite wall width and derive an expression for the thin-wall bubble