January 1997 arXiv papers — page 10

Michele Maggiore

We discuss some peculiar properties of the stochastic graviton background predicted by string cosmology. At Planckian times, for the values of the parameters of the model which are more interesting for the detection in gravitational wave experiments, the number density of gravitons is parametrically large compared to Planck density, and is peaked at small en

Kevin C. K. Chan

By using the Garfinkle, Horowitz and Strominger black hole solutions as examples, we illustrate that, with respect to the reference action functional proposed by Hawking and Horowitz, the asymptotic mass parameter is not invariant between two conformally related static spherically symmetric metrics.

Shoji Takada, John J. Portman, Peter G. Wolynes

The Langevin dynamics of a random heteropolymer and its dynamic glass transition are studied using elementary mode coupling theory. Contrary to recent reports using a similar framework, a discontinuous ergodic-nonergodic phase transition is predicted for all Rouse modes at a finite temperature T_A. For sufficiently long chains, T_A is almost independent of c

Louis Felix Feiner, Andrzej M. Oles, Jan Zaanen

We have studied the phase diagram and excitations of the spin-orbital model derived for a three dimensional perovskite lattice, as in KCuF_3. The results demonstrate that the orbital degeneracy drastically increases quantum fluctuations and suppresses the classical long-range order near the multicritical point in the mean-field phase diagram. This generates

U. M. S. Costa, M. L. Lyra, A. R. Plastino, C. Tsallis

Power-law sensitivity to initial conditions, characterizing the behaviour of dynamical systems at their critical points (where the standard Liapunov exponent vanishes), is studied in connection with the family of nonlinear 1D logistic-like maps $x_{t+1} = 1 - a | x_t |^z, (z > 1; 0 < a \le 2; t=0,1,2,...)$ The main ingredient of our approach is the generaliz

D. Foerster

To check the reliability of the Majorana representation of quantum spin systems, we use it to compute the ground state energy of an antiferromagnetic spin 1/2 chain to one loop order. We find a very small one loop correction of the mean field energy and a discrepancy of >100% compared to the Bethe Ansatz result. We conclude that a careful handling of the gau

A. O. Parry, P. S. Swain

We consider variational (density functional) models of fluids confined in parallel-plate geometries (with walls situated in the planes z=0 and z=L respectively) and focus on the structure of the pair correlation function G(r_1,r_2). We show that for local variational models there exist two non-trivial identities relating both the transverse Fourier transform

K. M. Kojima, Y. Fudamoto, M. Larkin, G. M. Luke

We report elastic neutron diffraction and muon spin relaxation (muSR) measurements of the quasi one-dimensional antiferromagnets Sr2CuO3 and Ca2CuO3, which have extraordinarily reduced TN/J ratios. We observe almost resolution-limited antiferromagnetic Bragg reflections in Sr2CuO3 and obtain a reduced ordered moment size of ~0.06 \muB. We find that the ratio

A. K. Kolezhuk, H. -J. Mikeska

We investigate the isotropic two-leg S=1/2 ladder with general bilinear and biquadratic exchange interactions between spins on neighboring rungs, and determine the Hamiltonians which have a matrix product wavefunction as exact ground state. We demonstrate that a smooth change of parameters leads one from the S=1/2 dimer and Majumdar-Ghosh chains to the S=1 c

Janne Ruostekoski, Juha Javanainen

We study the interactions of a possibly dense and/or quantum degenerate gas with driving light. Both the atoms and the electromagnetic fields are represented by quantum fields throughout the analysis. We introduce a field theory version of Markov and Born approximations for the interactions of light with matter, and devise a procedure whereby certain types o

Ronald Dickman, Phil Attard, Veronika Simonian

We perform extensive Monte Carlo simulations of binary hard-sphere mixtures (with diameter ratios of 5 and 10), to determine the entropic force between (1) a macrosphere and a hard wall, and (2) a pair of macrospheres. The microsphere background fluid (at volume fractions ranging from 0.1 to 0.34) induces an entropic force on the macrosphere(s); the latter c

Z. Kaufmann, H. Lustfeld, A. Nemeth, P. Szepfalusy

In this paper we investigate deterministic diffusion in systems which are spatially extended in certain directions but are restricted in size and open in other directions, consequently particles can escape. We introduce besides the diffusion coefficient D on the chaotic repeller a coefficient ${\hat D}$ which measures the broadening of the distribution of tr

Tommy Wiklind, Francoise Combes

New high-quality absorption spectra of J=0-1 HCO+, HCN, HNC and the J=1-2 line of CS towards the radio core of Cen A are presented and analysed. In addition, the J=0-1 line of of H13CO+ has been detected. The new high signal-to-noise HCO+ spectrum allows a comparison with results obtained more than 7 years earlier. No significant changes in the spectrum is f

L. Piro

The X-ray satellite BeppoSAX, a major programme of the Italian space agency with participation of the Dutch space agency, was successfully launched from Cape Canaveral on April 30, 1996. After a 2 months period devoted to engineering check out that confirmed the nominal functionality of the satellite and the scientific payload, we have performed a series of

Steinn Sigurdsson

The capture and subsequent inspiral of stellar mass black holes on eccentric orbits by central massive black holes, is one of the more interesting likely sources of gravitational radiation detectable by LISA. We estimate the rate of observable events and the associated uncertainties. A moderately favourable mass function could provide many detectable bursts

H. Matsumoto, K. Koyama, H. Awaki, T. Tsuru

We have systematically investigated the ASCA spectra of 12 early type galaxies. This paper presents the global spectral properties of these systems based on a larger sample than in any previous ASCA study.

S. Molendi, L. Chiappetti, G. Cusumano, D. Dal Fiume

In this contribution we discuss briefly a few calibration items relevant to the data analysis and present some preliminary scientific results. The discussion on instrumental topics focuses on the response matrix and Point Spread Function (PSF). In the scientific results section we discuss a first analysis of the two Seyferts MCG 6-30-15 and NGC 4151 and of t

V. I. Slysh, S. V. Kalenskii, I. E. Val&#39;tts, V. V. Golubev

A new methanol maser line 6(-1)-5(0)E at 133 GHz was detected with the 12-m Kitt Peak radio telescope using remote observation mode from Moscow. Moderately strong, narrow maser lines were found in DR21(OH), DR21-W, OMC-2, M8E, NGC2264, L379, W33-Met. The masers have similar spectral features in other transitions of methanol-E at 36 and 84 GHz, and in transit

Paolo Padovani

After briefly summarizing the main tenets of unified schemes of Active Galactic Nuclei, I review some recent results in the field of unification of radio-loud sources, both for the low-luminosity (BL Lacs and Fanaroff-Riley type I radio galaxies) and high-luminosity (radio quasars and Fanaroff-Riley type II radio galaxies) populations.

W. Kley, J. C. B. Papaloizou

The structure of the boundary layer region between the disc and a comparatively slowly rotating star is studied using a causal prescription for viscosity. The vertically integrated viscous stress relaxes towards its equilibrium value on a relaxation timescale $τ$, which naturally yields a finite speed of propagation for viscous information. For a standard al

Willy Kley

Sequences of infinitesimally thin, uniformly rotating, self-gravitating relativistic discs with internal two-dimensional pressure have been constructed. It is shown that in weaker relativistic configurations the sequences undergo a continuous bifurcation from a disc to a ring structure, while in stronger relativistic cases the sequences terminate at the mass

M. Catelan

Mergers of globular clusters (GCs) once associated with dwarf spheroidal (dSph) galaxies have recently been suggested as an explanation for the bimodal horizontal branches (HBs) of some Galactic GCs, most notably NGC 1851, NGC 2808, and NGC 6229. Through analysis of the available color-magnitude diagrams for the GCs in the Fornax and Sagittarius dSph satelli

Rennan Barkana

We present a new method for determining time delays among the light curves of various images in a gravitational lens. The method is based on constructing a simple model for the source variation and forming a chi squared measure of the agreement of this same variation with all of the lightcurves. While inspired by Press et al. (1992a, b) our approach is diffe

B. Dion, M. de Montigny, L. Marleau, G. Simon

We present the results of an analysis for the pair production of scalar leptoquarks at the CERN Large Hadron Collider (LHC) with energy=14 TeV and luminosity=10 fb^{-1} which includes the dominant sources of Standard Model background associated to this process: top-antitop, ZZ, WZ and Z*jj production. The top-antitop process provides the main source of backg

A. Yu. Orlov, P. Winternitz

The symmetry algebra $P_\infty = W_\infty \oplus H \oplus I_\infty$ of integrable systems is defined. As an example the classical Sophus Lie point symmetries of all higher KP equations are obtained. It is shown that one (``positive&#39;&#39;) half of the point symmetries belongs to the $W_\infty$ symmetries while the other (``negative&#39;&#39;) part belongs

Robert D. McClure

After 16 years of radial-velocity observations of a sample of 22 R-type carbon stars, no evidence for binary motion has been detected in any of them. This is surprising considering that approximately 20% of normal late-type giants are spectroscopic binaries, and the fraction is close to 100% in barium, CH, and subgiant/dwarf CH and barium stars. It is sugges

E. Dudas, J. Mourad

We analyze in detail the anomaly cancellation conditions for the strongly coupled $E_8 \times E_8$ heterotic string introduced by Horava and Witten and find new features compared to the ten-dimensional Green-Schwarz mechanism. We project onto ten dimensions the corresponding Lagrangian of the zero-mode fields. We find that it has a simple interpretation prov

James B. Hartle

Sources of predictability in the basic laws of physics are described in the most general theoretical context -- the quantum theory of the universe as a whole. (To appear in the Proceedings of the conference on Fundamental Sources of Unpredictability held at the Santa Fe Institute, March 28 to 30, 1996 to be published by Complexity.)

Daniel Duffy, Alexander Nazarenko, Stephan Haas, Adriana Moreo

Quantum Monte Carlo (QMC) and Maximum Entropy (ME) techniques are used to study the spectral function $A({\bf p},ω)$ of the one band Hubbard model in strong coupling including a next-nearest-neighbor electronic hopping with amplitude $t&#39;/t= -0.35$. These values of parameters are chosen to improve the comparison of the Hubbard model with angle-resolved ph

O. Heinonen, M. I. Lubin, M. D. Johnson

We review an ensemble density functional approach to spin-polarized inhomogeneous quantum Hall systems. Recent work on generalizations to include spin degrees of freedom is summarized at the end of the manuscript.

Rainer Dick

I calculate the potential of a pointlike particle carrying SU$(N_c)$ charge in a gauge theory with a dilaton. The solution depends on boundary conditions imposed on the dilaton: For a dilaton that vanishes at infinity the resulting potential is of the form $(r+r_ϕ)^{-1}$, with $r_ϕ$ inverse proportional to the decay constant of the dilaton. Another natural c

Klaus Behrndt

In this talk I address some aspects in the recent developments for N=2 black holes in 4 dimensions. I restrict myself on axion-free solutions that can classically be related to intersections of isotropic $D$- or $M$-branes. After reviewing of some classical properties I include corrections coming from a general cubic prepotential. On the heterotic side these

Pietro Fre'

In this lecture I review recent results on the first order equations describing BPS extremal states, in particular N=2 extremal black-holes. The role of special geometry is emphasized also in the rigid theory and a comparison is drawn with the supersymmetric derivation of instantons and hyperinstantons in topological field theories. Work in progress on the a

F G Scholtz, S V Shabanov

We investigate the way in which the Gribov problem is manifested in the BRST quantization of simple quantum mechanical models by comparing models with and without a Gribov problem. We show that the hermiticity and nilpotency of the BRST charge together with the Batalin-Vilkovisky theorem yield non-trivial supplementary conditions on gauge fixing fermions. If

A S Vytheeswaran

We show that the abelian Proca model, which is gauge non-invariant with second class constraints can be converted into gauge theories with first class constraints. The method used, which we call Gauge Unfixing employs a projection operator defined in the original phase space. This operator can be constructed in more than one way, and so we get more than one

Masahiko Miyamoto

We give a new construction of the moonshine VOA V^{\natural} over the real number field. We proved that V^{\natural} has a positive definite invariant bilinear form and its full automorphism group is the Monster simple group. We also construct an infinite series of meromorphic VOAs whose full automorphism groups are finite. We calculate the trace form on V^{

Tad Hogg

A quantum algorithm for general combinatorial search that uses the underlying structure of the search space to increase the probability of finding a solution is presented. This algorithm shows how coherent quantum systems can be matched to the underlying structure of abstract search spaces, and is analytically simpler than previous structured search methods.

Yves Brihaye, Jean Nuyts

Let $P(N,V)$ denote the vector space of polynomials of maximal degree less than or equal to $N$ in $V$ independent variables. This space is preserved by the enveloping algebra generated by a set of linear, differential operators representing the Lie algebra $gl(V+1)$. We establish the counterpart of this property for the vector space $P(M,V) \oplus P(N,V)$ f

Jens Lieberum

This paper contains a proof that chromatic weight systems, introduced by Chmutov, Duzhin and Lando, can be expressed in terms of weight systems associated with direct sums of the Lie algebras gl_n and so_n. As a consequence the Vassiliev invariants of knots corresponding to the chromatic weight systems distinguish exactly the same knots as a one variable spe

A. Amatuni, S. G. Arutunian, M. R. Mailian

It is shown that high accelerating gradient can be obtained in a specially constructed system of electron (positron) bunches, moving in cold plasma,with definite density. These combined bunch systems do not generate the wake fields behind them and can pass through the plasma column in a periodic sequence. The consideration is carried out numericaly and analy

Eric D&#39;Hoker, D. H. Phong

We set up a systematic expansion of the prepotential for ${\cal N}=2$ supersymmetric Yang-Mills theories with SU(N) gauge group in the region of strong coupling where a maximal number of mutually local fields become massless. In particular, we derive the first non-trivial non-perturbative correction, which is the first term in the strong coupling expansion p

F. Ruiz Ruiz, P. van Nieuwenhuizen

We prove that three-dimensional N=1 supersymmetric Yang-Mills-Chern-Simons theory is finite to all loops. This leaves open the possibility that different regularization methods give different finite effective actions. We show that for this model dimensional regularization and regularization by dimensional reduction yield the same effective action.

G W Gibbons

Recent results of Trudinger on Isoperimetric Inequalities for non-convex bodies are applied to the gravitational collapse of a lightlike shell of matter to form a black hole. Using some integral identities for co-dimension two surfaces in Minkowski spacetime, the area $A$ of the apparent horizon is shown to be bounded above in terms of the mass $M$ by the $1

Jamal Jalilian-Marian, Alex Kovner, Andrei Leonidov, Heribert Weigert

We discuss the Wilson renormalization group approach to the effective action for low $x$ physics. It is shown that in the linearized, weak field regime the RG equation reduces to the BFKL equation for the evolution of the unintegrated gluon density. We discuss the relation of this approach with that of Lipatov.

E. H. Simmons

We briefly describe the structure and phenomenology of a flavor-universal extension of the strong interactions, focusing on the color-octet of massive gauge bosons (`colorons&#39;) present in the low-energy spectrum. We discuss current limits on the colorons and what future measurements may reveal.

H. J. Pirner, M. Wachs

We investigate the thermal behavior of quarks and antiquarks interacting via a temperature-dependent linear potential. The quarks are constituent quarks with dynamically generated masses from the background linear $σ$-model.We find a transition from a system of bound mesons to a correlated quark gas at the same temperature as the chiral transition temperatur

Ulf-G. Meißner

I review recent results in baryon chiral perturbation theory, in particular related to pion-nucleon scattering and first systematic attempts to go beyond next-to-leading order in the case of three flavors. New insight into the chiral expansion of the baryon masses and magnetic moments is presented.

H. Arthur Weldon

The thermal self-energy of gluons generally depends on four Lorentz-invariant functions. Only two of these occur in the hard thermal loop approximation of Braaten and Pisarski because of the abelian Ward identity $K_μΠ^{μν}_{\rm htl}=0$. However, for the exact self-energy $K_μΠ^{μν}\neq 0$. In linear gauges the Slavnov-Taylor identity is shown to require a n

Marco Ciuchini

Three years after the completion of the next-to-leading order calculation, the status of the theoretical estimates of $ε&#39;/ε$ is reviewed. In spite of the theoretical progress, the prediction of $ε&#39;/ε$ is still affected by a 100% theoretical error. In this paper the different sources of uncertainty are critically analysed and an updated estimate of $ε

K. G. Chetyrkin, B. A. Kniehl, M. Steinhauser

We calculate the top-quark-induced three-loop corrections of O(alpha_s^2 G_F M_t^2) to the Yukawa couplings of the first five quark flavours in the framework of the minimal standard model with an intermediate-mass Higgs boson, with mass M_H << 2M_t. The calculation is performed using an effective-Lagrangian approach implemented with the hard-mass procedure.

Robert H. Brandenberger

Modern cosmology has created a tight link between particle physics / field theory and a wealth of new observational data on the structure of the Universe. These lecture notes focus on some of the most important aspects concerning the connection between theory and observations. The lectures begin with an overview of some recent progress and problems in inflat

M. Bishai

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we present new measurements of the branching fractions for $D^+ \to K_S K^+$ and $D^+ \to K_S π^+$. These results are combined with other CLEO measurements to extract the ratios of isospin amplitudes and phase shifts for $D \to KK$ and $D \to Kπ$.

L. Ludovici, P. Zucchelli

We study the conceptual feasibility of a high energy, ``short baseline&#39;&#39;, zero background experiment to search for muon-neutrino --> electron-neutrino oscillations and fully covering the area where the LSND experiment claims evidence. The natural electron-neutrino background of the muon-neutrino beam, from K and mu decays in the decay tunnel, is supp

C. Barrabes, G. F. Bressange

We study singular hypersurfaces in tensor multi-scalar theories of gravity. We derive in a distributional and then in an intrinsic way, the general equations of junction valid for all types of hypersurfaces, in particular for lightlike shells and write the general equations of evolution for these objects. We apply this formalism to various examples in static

C. Barrabes, G. F. Bressange, P. A. Hogan

The Barrabès-Israel theory of light-like shells in General Relativity is used to show explicitly that in general a light-like shell is accompanied by an impulsive gravitational wave. The gravitational wave is identified by its Petrov Type N contribution to a Dirac delta-function term in the Weyl conformal curvature tensor (with the delta-function singular on

U. Bunke, H. Koch

We consider families of Dirac operators on the unit interval which depend on parameters via boundary conditions. We study the associated eta forms and Maslov cocyles. With this simple example we show how previous results of Lesch/Woiciechowski and the first author on the eta invariant of cylinders generalize to the family case.

Ivo Souza, Jose Luis Martins

We propose a new variable cell-shape molecular dynamics algorithm where the dynamical variables associated with the cell are the six independent dot products between the vectors defining the cell instead of the nine cartesian components of those vectors. Our choice of the metric tensor as the dynamical variable automatically eliminates the cell orientation f

Alvaro Corral, Conrad J. Perez, Albert Diaz-Guilera

We have studied the collective behavior of a population of integrate-and-fire oscillators. We show that diversity, introduced in terms of a random distribution of natural periods, is the mechanism that permits to observe self-organized criticality (SOC) in the long time regime. As diversity increases the system undergoes several transitions from a supercriti

Reggie Brown, Nikolai F. Rulkov

We examine synchronization between identical chaotic systems. A rigorous criteria is presented which, if satisfied, guarantees that the coupling produces linearly stable synchronous motion. The criteria can also be used to design couplings that lead to stable synchronous motion. Analytical results from a dynamical system are presented.

H. Rehfeld, H. Alt, C. Dembowski, H. -D. Graef

During the last few years we have studied the chaotic behavior of special Euclidian geometries, so-called billiards, from the quantum or in more general sense "wave dynamical" point of view. Due to the equivalence between the stationary Schroedinger equation and the classical Helmholtz equation in the two-dimensional case (plain billiards), it is possible to

C. R. Robinson, B. A. Harmon, M. L. McCollough, W. S. Paciesas

The operation of CGRO/BATSE continues to produce, after more than 5 years, a valuable database for the study of long-term variability in bright hard X-ray sources. The all-sky capability of BATSE provides, using the Earth occultation technique, up to approximately 30 flux measurements per day for each source. The long BATSE baseline and the numerous rising a

V. Karas

Fourier power spectra and phases of a signal from a large number of radiating sources orbiting around a black hole are investigated. It is assumed that the individual sources (bright spots) are located in an accretion disc and their lifetime exceeds the corresponding orbital period. This model is relevant for the short-time X-ray variability of active galact

Ewa Szuszkiewicz, John C. Miller

Nonlinear time-dependent calculations have been carried out in order to study the evolution of the thermal instability for optically thick, transonic, slim accretion discs around black holes. In the present calculations we have investigated only the original version of the slim disc model with low viscosity. This version does not yet contain several importan

John D. Barrow, Pedro G. Ferreira, Joseph Silk

We derive an upper limit of $B_0<3.4\times 10^{-9}(Ω_0h_{50}^2)^{1/2}$ Gauss on the present strength of any primordial homogeneous magnetic field. The microwave background anisotropy created by cosmological magnetic fields is calculated in the most general flat and open anisotropic cosmologies containing expansion-rate and 3-curvature anisotropies. Our limit

Eduardo Telles, Jorge Melnick, Roberto Terlevich

We present CCD images of a sample of 39 HII galaxies taken at the Danish 1.54m telescope on La Silla. The images are used to analyse the morphology of these emission line dwarfs, and the structural properties of the knots of star formation and of the underlying galaxy. The sizes of the starbursts are measured. We propose a morphological classification based

C. Allende Prieto, R. J. Garcia Lopez, J. Trujillo Bueno

Line asymmetries and shifts are a powerful tool for studying velocity fields in the stellar photospheres. Other effects, however, could also generate asymmetries blurring the information of the velocity patterns. We have studied the shifts and asymmetries induced in the profiles of spectral lines by pressure effects. The best theoretical and experimental dat

Sergei Nikolaev, Martin D. Weinberg

Previous work reported a bar signature in color-selected IRAS variable stars. Here, we estimate the source density of these variables while consistently accounting for spatial incompleteness in data using a likelihood approach. The existence of the bar is confirmed with shoulder of 4 kpc and position angle of 19 +/- 1 degrees. The ratio of non-axisymmetric t

L. R. Bellot Rubio, B. Ruiz Cobo, M. Collados

First results of the inversion of Stokes I and V profiles from plage regions near disk center are presented. Both low and high spatial resolution spectra of FeI 6301.5 and FeI 6302.5 A obtained with the Advanced Stokes Polarimeter (ASP) have been considered for analysis. The thin flux tube approximation, implemented in an LTE inversion code based on response

Mario Vietri, Andrea Ferrara, Francesco Miniati

We consider the stability of clouds surrounded by a hotter confining medium with respect to which they are in motion, against Kelvin-Helmholtz instabilities (KHI). In the presence of cooling, sound waves are damped by dissipation. Whenever cooling times are shorter than sound crossing times, as they are in the normal interstellar medium, this implies that th

Jayaram N. Chengalur, Robert Braun, W. Butler Burton

We report on a deep search with the Westerbork Synthesis Radio Telescope towards the galactic anticenter for the 327 MHz hyperfine transition of DI. This is a favorable direction for a search because: (i) the HI optical depth is high due to velocity crowding; (ii) the observed molecular column density is low (implying that most of the deuterium would probabl

Yujiro Kawamata

We prove some version of Morrison&#39;s conjecture on the cone of divisors for Calabi-Yau fiber spaces with non-trivial base pace whose total space is 3-dimensional.

B L Feigin, A M Semikhatov, I Yu Tipunin

Highest-weight type representation theories of the affine sl(2) and N=2 superconformal algebras are shown to be equivalent modulo the respective spectral flows.

Vitorio A. De Lorenci, Jerome Martin, Nelson Pinto-Neto, Ivano Damiao Soares

We develop the canonical quantization of a midisuperspace model which contains, as a subspace, a minisuperspace constituted of a Friedman-Lema\^ıtre-Robertson-Walker Universe filled with homogeneous scalar and dust fields, where the sign of the intrinsic curvature of the spacelike hypersurfaces of homogeneity is not specified, allowing the study of topology

Ralf D. Tscheuschner

We review the fundamentals of Jahn-Teller interactions and their field theoretical modelings and show that a 2+1 dimensional gauge theory where the gauge field couples to &#34;flavored fermions&#34; arises in a natural way from a two-band model describing the dynamical Jahn-Teller effect. The theory exhibits a second order phase transition to novel finite-te

Amit Giveon, Oskar Pelc, Eliezer Rabinovici

We consider N=1 supersymmetric gauge theories with a simple classical gauge group, one adjoint $Φ, N_f$ pairs ($Q_i,\tilde{Q_i}$) of (fundamental, anti-fundamental) and a tree-level superpotential with terms of the Landau-Ginzburg form $\tilde{Q}_iΦ^lQ_j$. The quantum moduli space of these models includes a Coulomb branch. We find hyperelliptic curves that e

F. Becattini

It is shown that the hadron production in high energy pp, p{\bar p} and e^+e^- collisions, calculated by assuming that particles originate in hadron gas fireballs at thermal and partial chemical equilibrium, agrees very well with the data. The temperature of the hadron gas fireballs, determined by fitting hadron abundances, does not seem to depend on the cen

Fyodor V. Tkachov

Error enhancement properties of data processing algorithms in elementary particle physics measurements are discussed. It is argued that a systematic use of continuous weights instead of hard cuts may reduce errors of the results at the cost of a marginal increase of computer resources needed.

M. Kachelriess, C. Wilke, G. Wunner

The energy loss rate of a magnetized electron gas emitting axions a due to the process $e^- \to e^- +a$ is derived for arbitrary magnetic field strength B. Requiring that for a strongly magnetized neutron star the axion luminosity is smaller than the neutrino luminosity we obtain the bound $g_{ae}\lsim 10^{-10}$ for the axion electron coupling constant. This

Fyodor V. Tkachov

This summary of several talks given in 1990-1993 discusses the problem of asymptotic expansions of multiloop Feynman diagrams in masses and external momenta - a central problem in perturbative quantum field theory. Basic principles of the theory of asymptotic operation -- the most powerful tool for that purpose -- are discussed. Its connection with the conve

M. Hirsch, H. V. Klapdor-Kleingrothaus, S. G. Kovalenko

We prove a low-energy theorem valid for any model of weak scale softly broken supersymmetry. It claims that the neutrino Majorana mass, the B-L violating mass of the sneutrino and the neutrinoless double beta decay amplitude are intimately related to each other such that if one of them is non-zero the other two are also non-zero and, vice versa, if one of th

H. Monden, H. Suganuma, H. Ichie, H. Toki

We study the surface tensions in the mixed phase of QCD in the dual Ginzburg-Landau theory, where the QCD-monopole condensate is the order parameter on the confinement. First, we consider the thermal mixed phase, and derive the analytical expressions for the surface tension and the boundary thickness in terms of the shape of the effective potential. We study

L. D. Paniak, G. W. Semenoff, A. R. Zhitnitsky

Using the well established machinery of Wilson loop calculations we investigate the multiple vacua of two dimensional Yang-Mills theories with infinitely massive adjoint matter. In particular, via group theoretical techniques we calculate string tensions between charges and find the number of vacua for each compact Lie symmetry group. The counting of vacua i

Vadim A. Kuzmin

A new concept of generation of the cosmological baryon excess along with the cold dark matter (CDM) in the Universe is proposed and corresponding scenarios are outlined. Possible realizations of the idea in the framework of supersymmetric models are considered and constraints (predictions) on masses of sparticles compatible with the viability of the scenario

D. C. Ralph, C. T. Black, M. Tinkham

We have investigated the spectrum of discrete electronic states in single, nm-scale Al particles incorporated into new tunneling transistors, complete with a gate electrode. The addition of the gate has allowed (a) measurements of the electronic spectra for different numbers of electrons in the same particle, (b) greatly improved resolution and qualitatively

C. J. A. P. Martins

The velocity-dependent `one-scale&#39; model of Martins and Shellard is used to study the evolution of a cosmic string network (and the corresponding loop population) in open universes. It is shown that in this case there is no linear scaling regime and that even though curvature still dominates the dynamics, at late times strings become the main component o

James B. Hartle

Two fundamental laws are needed for prediction in the universe: (1) a basic dynamical law and (2) a law for the cosmological initial condition. Quantum cosmology is the area of basic research concerned with the search for a theory of the initial cosmological state. The issues involved in this search are presented in the form of eight problems. (To appear in

S. V. Kozyrev

Free coherent states for a system with two degrees of freedom is defined. Existence of the homeomorphism of the ring of integer 2-adic numbers to the set of coherent states corresponding to an eigenvalue of the operator of annihilation is proved. It is shown that the metric of free Fock space induces the 2-adic topology on the set of coherent states.

J. F. Cai, G. X. Ju, K. Wu, S. K. Wang

We extend Yangian double to super (or graded) case and give its Drinfel&#39;d generators realization by Gauss decomposition.

A. V. Shapovalov, E. V. Evdokimov

We present a Hamiltonian approach for the wellknown Eigen model of the Darwin selection dynamics. Hamiltonization is carried out by means of the embedding of the population variable space, describing behavior of the system, into the space of doubled dimension by introducing additional dynamic variables. Besides the study of the formalism, we try to interpret

Hong-An Peng, Shi-Hua Zhao, Cong-Feng Qiao

We discuss in this paper the possible contributions from R_ρ(ρ-reggeon associated with ρmeson) in DIS process on protons. Using results from phenomenological analysis of high energy π-N charge-exchanged scattering process, we get the expression of effective propagator of R_ρand the coupling constant β_ρbetween R_ρand light quarks. As a simple and concrete ex

H. M. Antia

Gravitational collapse of a spherically symmetric cloud has been extensively studied to investigate the nature of resulting singularity. However, there has been considerable debate about the admissibility of certain initial density distributions. Using the Newtonian limit of the equations governing collapse of a fluid with an equation of state $p=p(ρ)$ it is

Luiz A. Ferreira, Joaquin Sanchez Guillen

We argue that one of the basic ingredients for the appearance of soliton solutions in integrable hierarchies, is the existence of ``vacuum solutions&#39;&#39; corresponding to Lax operators lying in some abelian subalgebra of the associated affine Kac-Moody algebra. Using the dressing transformation we construct the solutions in the orbit of those vacuum sol

K. S. Virbhadra

We show that the well-known most general static and spherically symmetric exact solution to the Einstein-massless scalar equations given by Wyman is the same as one found by Janis, Newman and Winicour several years ago. We obtain the energy associated with this spacetime and find that the total energy for the case of the purely scalar field is zero.

Alex Hansen, Mogens H. Jensen, Kim Sneppen, Giovanni Zocchi

We propose a protein model based on a hierarchy of constraints that force the protein to follow certain pathways when changing conformation. The model exhibits a first order phase transition, cooperativity and is exactly solvable. It also shows an unexpected symmetry between folding and unfolding pathways as suggested by a recent experiment.

Paolo Muratore Ginanneschi

The mass transport by a Burgers velocity field is investigated in the framework of the theory of stochastic processes. Much attention is devoted to the limit of vanishing viscosity (inviscid limit) describing the &#34;adhesion model&#34; for the early stage of the evolution of the Universe. In particular the mathematical foundations for the ansatz currently

Beatriz Gato-Rivera, Jose Ignacio Rosado

We analyze several issues concerning the singular vectors of the Topological N=2 Superconformal algebra. First we investigate which types of singular vectors exist, regarding the relative U(1) charge and the BRST-invariance properties, finding four different types in chiral Verma modules and twenty-nine different types in complete Verma modules. Then we stud

Fabio Gavarini

Inspired by a result in [Ga], we locate two $ k[q,q^{-1}] $-integer forms of $ F_q[SL(n+1)] $, along with a presentation by generators and relations, and prove that for $ q=1 $ they specialize to $ U({\mathfrak{h}}) $, where $ {\mathfrak{h}} $ is the Lie bialgebra of the Poisson Lie group $ H $ dual of $ SL(n+1) $; moreover, we explain the relation with [loc

R. Argurio, F. Englert, L. Houart

We present a general rule determining how extremal branes can interesect in a configuration with zero binding energy. The rule is derived in a model independent way and in arbitrary spacetime dimensions $D$ by solving the equations of motion of gravity coupled to a dilaton and several different $n$-form field strengths. The intersection rules are all compati

E. E. Podkletnov

A high-temperature YBa_2Cu_3O_{7-x} bulk ceramic superconductor with composite structure has revealed weak shielding properties against gravitational force while in a levitating state at temperatures below 70 K. A toroidal disk was prepared using conventional ceramic technology in combination with melt-texture growth. Two solenoids were placed around the dis

M. Caselle, M. Hasenbusch

We present a high precision Monte Carlo study of various universal amplitude ratios of the three dimensional Ising spin model. Using state of the art simulation techniques we studied the model close to criticality in both phases. Great care was taken to control systematic errors due to finite size effects and correction to scaling terms. We obtain $C_+/C_-=4