July 1996 arXiv papers — page 7

W. Franzki

We investigate a strongly coupled U(1) gauge theory with fermions and scalars on the lattice and analyze whether the continuum limit might be a renormalizable theory with dynamical mass generation. Most attention is paid to the phase with broken chiral symmetry in the vicinity of the tricritical point found in the model. There we investigate the scaling of t

I. Montvay

The perspectives of numerical simulations in supersymmetric quantum field theories with vector-like gauge symmetries are discussed. A numerical simulation algorithm for SU(2) gauge theory with gluinos is studied and the first results on the glueball-gluinoball spectrum are presented.

Pablo Laguna, Wojciech Hubert Zurek

Numerical study of order parameter dynamics in the course of second order (Landau-Ginzburg) symmetry breaking transitions shows that the density of topological defects, kinks, is proportional to the fourth root of the rate of the quench. This confirms the more general theory of domain-size evolution in the course of symmetry breaking transformations proposed

Q. -S. Chi, S. A. Merkulov, L. J. Schwachhöfer

It is proved that the Lie groups $\E_7^{(5)}$ and $\E^{(7)}_7$ represented in $\R^{56}$ and the Lie group $\E_7^{\C}$ represented in $\R^{112}$ occur as holonomies of torsion-free affine connections. It is also shown that the moduli spaces of torsion-free affine connnections with these holonomies are finite dimensional, and that every such connection has a l

Wojciech Hubert Zurek

Topological defects are thought to be left behind by the cosmological phase transitions which occur as the universe expands and cools. Similar processes can be studied in the phase transitions which take place in the laboratory: ``Cosmological'' experiments in superfluid He$^4$ and in liquid crystals were carried out within the past few years, and th

G. Iannaccone, M. Macucci, B. Pellegrini

We propose a quantum mechanical approach to noise in resonant tunneling structures, that can be applied in the whole range of transport regimes, from completely coherent to completely incoherent. In both limiting cases, well known results which have appeared in the literature are recovered. Shot noise reduction due to both Pauli exclusion and Coulomb repulsi

M. B. Hastings, L. S. Levitov

A theory is presented for tunneling between compressible regions on the sides of a narrow incompressible Quantum Hall strip. Assuming that electron interactions lead to formation of a Wigner crystal on the edges of the compressible regions, we consider the situation when the non-conservation of electron momentum required for transport is provided, in the abs

Daniel A. Stariolo

We present results of a Monte Carlo simulation of an Heisenberg Spin Glass model on a hipercubic cell of size 2 in {\it D} dimensions. Each spin interacts with {\it D} nearest neighbors and the lattice is expected to recover the completely connected (mean field) limit as $D\rightarrow \infty$. An analysis of the Binder parameter for $D=8, 9$ and $10$ shows c

Chooi-Gim Rosy Teh, W. K. Koo, B. S. Lee

Jacobian elliptic travelling wave solutions for a new Hamiltonian amplitude equation determining some instabilities of modulated wave train are obtained. By mere variation of the Jacobian elliptic parameter $k^2$ from zero to one, these solutions are transformed from a trivial one to the known solitary solutions.

WonIl Lee, Geunbae Lee, Jong-Hyeok Lee

A new scheme to represent phonological changes during continuous speech recognition is suggested. A phonological tag coupled with its morphological tag is designed to represent the conditions of Korean phonological changes. A pairwise language model of these morphological and phonological tags is implemented in Korean speech recognition system. Performance o

E. S. Mchedlova, D. I. Trubetskov

The processes in nonequilibrium dissipative media caused by coherent structure formation and lead to the complicated dynamics are of interest for nonlinear physics. Here we consider a model of the flow of interacting electronics patterns. Under electronic pattern we understand a small volume of active media, containing electron oscillators. The superradiatio

Ian J Grivell, Andrew R Liddle

We use a numerical code for accurate computation of the amplitude of linear density perturbations and gravitational waves generated by single-field inflation models to study the accuracy of existing analytic results based on the slow-roll approximation. We use our code to calculate the coefficient of an expansion about the exact analytic result for power-law

Carl J. Grillmair, Tod R. Lauer, Guy Worthey, S. M. Faber

We present a V-I color-magnitude diagram for a region 1'-2' from the center of M32 based on Hubble Space Telescope WFPC2 images. The broad color-luminosity distribution of red giants shows that the stellar population comprises stars with a wide range in metallicity. This distribution cannot be explained by a spread in age. The blue side of the giant

Max Pettini, David L King, Linda J Smith, Richard W Hunstead

Measurements of Zn and Cr abundances in damped Lyman alpha systems at absorption redshifts between 0.692 and 3.390 show that metals and dust are much less abundant in high redshift galaxies than in the Milky Way today. We conclude that the overall degree of metal enrichment of DLA galaxies approximately 13.5 Gyr ago is 1/15 solar. The depletion of Cr is appr

Y. K. Ng, G. Bertelli

An analysis is made on the morphology of the sequences, formed by stars distributed along the line of sight in (V,V--I) colour-magnitude diagrams from Baade's Window (l=1.0,b=-3.9). The extinction is due to an absorbing layer with an effective thickness of about 100 pc. A linearly, with distance, increasing extinction up to a maximum value inside the abs

Y. K. Ng

Monte-Carlo simulations of optical and near-infrared colour-magnitude diagrams in Baade's Window (l=1.0,b=-3.9) are compared with each other. The morphological structure of the red horizontal branch in those CMDs is likely due to a combination of extinction and age-metallicity of the stars from the bulge/bar. In contrast with the optical (V,I) passbands,

Peter J. S. Watson

Galactic collisions are normally modeled in a CDM model by assuming the DM consists of a small number of very massive objects. This note shows that the behaviour of a CDM halo during collisions depends critically on the mass of the particles that make it up, and in particular, all halo particles below a certain characteristic mass are likely to be lost.

Y. K. Ng

The results, obtained with the stellar population synthesis technique, are summarized for galactic structure and stellar population studies of our Galaxy. Emphasis is put on the analysis (extinction, disc structure, bar population) of the OGLE colour-magnitude diagram from Baade's Window.

Emory F. Bunn

We review the physical processes that are thought to produce anisotropy in the cosmic microwave background, focusing primarily (but not exclusively) on the effects of acoustic waves in the early Universe. We attempt throughout to supply an intuitive, physical picture of the key ideas and to elucidate the ways in which the predicted anisotropy depends on cosm

Richard Hain

The Hodge de Rham theory of relative Malcev completion is developed in this paper. In the special case where one takes the corresponding reductive group to be trivial, one recovers Chen's de Rham theory of the fundamental group and the corresponding Hodge theory due to Morgan and the author. This work is a principal technical tool in the author's wor

Pablo Ares Gastesi

The Torelli group of a compact non-orientable Klein surface is the subgroup of the modular group consisting of the mapping classes that act trivially on the first homology group of the surface. We prove that if a surface has genus at least $3$, then the Torelli group acts fixed points free on the Teichmüller space of the surface. That gives an embedding of t

Sergey Finashin, Eugenii Shustin

It is proven that for any topological or analytical types of isolated singular points of plane curves, there exists a non-real irreducible plane algebraic curve of degree $d$ which goes through $d^2$ real distinct points and has imaginary singular points of the given types. This result is used to construct a series of examples of complex algebraic surfaces $

Nir Polonsky

We review a recently proposed framework in which the neutrino mass is a signal of supersymmetry breaking and is suppressed dynamically. In addition, we briefly comment on some possible consequences of general lepton-number violation in supersymmetric theories, e.g., dijet and multijet signals and $jj \rightarrow llγγ$.

Peter H. Hauschildt, E. Baron, France Allard

We describe the parallel implementation of our generalized stellar atmosphere and NLTE radiative transfer computer program PHOENIX. We discuss the parallel algorithms we have developed for radiative transfer, spectral line opacity, and NLTE opacity and rate calculations. Our implementation uses a MIMD design based on a relatively small number of MPI library

J. F. Gunion, P. Martin

We evaluate the prospects for measuring $BR(h\to\gamma\gamma)$ for a Standard-Model-like Higgs boson at the Next Linear $e^+e^-$ Collider in the $e^+e^-\to Z^*\to Z h$ and $e^+e^-\to\nu_e\anti\nu_e h$ production modes. Relative merits of different machine energy/luminosity strategies and different electromagnetic calorimeter designs are evaluated. We emphasi

Toshio Tsukamoto, Yoshimasa Kurihara

We present a study of single-W production ($e^+e^-\to e^-\barν_e W^+$) as a new probe of the anomalous couplings at the LEP energy region. We introduce simple cuts to separate the single-W process from W-pair production and have performed cross-section calculations using 4-fermion generator ``grc4f''. The cross-section of the single-W process is foun

Zurab Kakushadze, S. -H. Henry Tye

We generalize the rules for the free fermionic string construction to include other asymmetric orbifolds with world-sheet bosons. We use these rules to construct various grand unified string models that involve level-3 current algebras. We present the explicit construction of three classes of 3-chiral-family grand unified models in the heterotic string theor

Dirk Kreimer

We investigate to what extent renormalization can be understood as an algebraic manipulation on concatenated one-loop integrals. We find that the resulting algebra indicates a useful connection to knot theory as well as number theory and report on recent results in support of this connection.

S. Jadach, M. Melles, B. F. L. Ward, S. A. Yost

In this contribution we give a short overview of the situation in the precision calculation of the Bhabha process and we present a preliminary numerical result on the second-order sub-leading correction to the small angle Bhabha process.

János Kollár

These are the notes of my lectures at the 1996 European Congress of Mathematicians. {} Polynomials appear in mathematics frequently, and we all know from experience that low degree polynomials are easier to deal with than high degree ones. It is, however, not clear that there is a well defined class of "low degree" polynomials. For many questions, po

D. A. Restrepo

We present the realization of a mechanism that generates all mases and mixing angles by using the top quark as seed in the context of an anomaly free abelian extension of the standard model.

M. Bianchetti, M. R. Quaglia, G. Colo`, P. M. Pizzochero

The K-electron capture half-life of $^{123}$Te has been recently measured to be $t^K_{exp}=2.4\times 10^{19}$ yr, and constitutes the longest half-life ever measured in a single $β$-transition of any nuclear species. We have calculated this second unique forbidden transition within the framework of the proton-neutron quasi-particle random phase approximation

Stefano De Leo, Khaled Abdel-Khalek

Octonionic algebra being nonassociative is difficult to manipulate. We introduce left-right octonionic barred operators which enable us to reproduce the associative GL(8,R) group. Extracting the basis of GL(4,C), we establish an interesting connection between the structure of left-right octonionic barred operators and generic 4x4 complex matrices. As an appl

Christian Okonek, Alexander Schmitt, Andrei Teleman

We construct master spaces for oriented torsion free sheaves coupled with morphisms into a fixed reference sheaf. These spaces are projective varieties endowed with a natural $\C^*$-action. The fixed point set of this action contains the moduli space of semistable oriented torsion free sheaves and the quot scheme associated with the given data. In the case o

A. Klemm, P. Mayr, C. Vafa

We study the BPS states of non-critical strings which arise for zero size instantons of exceptional groups. This is accomplished by using F-theory and M-theory duals and by employing mirror symmetry to compute the degeneracy of membranes wrapped around 2-cycles of the Calabi-Yau threefold. We find evidence for a number of novel physical phenomena, including

Rafael Ferraro

An ordinary unambiguous integral representation for the finite propagator of a quantum system is found by starting of a privileged skeletonization of the functional action in phase space, provided by the complete solution of the Hamilton-Jacobi equation. This representation allows to regard the propagator as the sum of the contributions coming from paths whe

B. Z. Kopeliovich, J. Nemchik, E. Predazzi

We present a space-time description of hadronization of highly virtual quarks originating from a deep-inelastic electron scattering (DIS). Important ingredients of our approach are the time- and energy--dependence of the density of energy loss for gluon radiation, the Sudakov's suppression of no radiation, and the effect of color transparency, which supp

B. Z. Kopeliovich, B. Povh

Nuclear shadowing corrections are dominated by soft interaction and grow as function of $1/x$ more slowly than the single scattering term, which has an essential contribution from hard interaction. Therefore, we predict vanishing nuclear shadowing at very low $x$ provided that $Q^2$ is high and fixed. At the same time, at medium and low $Q^2$, nuclear shadow

J. Huefner, B. Z. Kopeliovich

Interference between vector mesons electroproduced at different longitudinal coordinates leads within Glauber approximation to a $Q^2$-dependence of nuclear effects similar to what is expected to be an onset of color transparency (CT). We suggest such a mapping of the photon energies and virtualities, which eliminates the undesirable $Q^2$-variation and allo

J. Huefner, B. Z. Kopeliovich, Al. B. Zamolodchikov

The nuclear enhancement observed in inelastic photoproduction of $J/Ψ$ should not be interpreted as evidence for an increased gluon density in nuclei. The nuclear suppression of the production rate due to initial and final state interactions is calculated and a novel two-step color exchange process is proposed, which is able to explain the data.

Laurent Baulieu, Alexander Rozenberg, Martin Schaden

For an $S_4$ space-time manifold global aspects of gauge-fixing are investigated using the relation to Topological Quantum Field Theory on the gauge group. The partition function of this TQFT is shown to compute the regularized Euler character of a suitably defined space of gauge transformations. Topological properties of the space of solutions to a covarian

M. Gasperini

I discuss the status of present knowledge about a possible background of relic gravitons left by an early, pre-big bang cosmological epoch, whose existence in the past of our Universe is suggested by the duality symmetries of string theory.

S. Sethi, M. Stern

We consider the question of ground states in the supersymmetric system that arises in the search for the missing H-monopole states. By studying the effective theory near certain singularities in the five-brane moduli space, we find the remaining BPS states required by the conjectured S-duality of the toroidally compactified heterotic string.

Joseph D. Lykken

The string duality revolution calls into question virtually all of the working assumptions of string model builders. A number of difficult questions arise. I use fractional charge as an example of a criterion which one would hope is robust beyond the weak coupling heterotic limit. Talk given at the 5th International Workshop on Supersymmetry and Unification

Viktor Abramov, Richard Kerner, Bertrand Le Roy

We propose a generalization of non-commutative geometry and gauge theories based on ternary Z_3-graded structures. In the new algebraic structures we define, we leave all products of two entities free, imposing relations on ternary products only. These relations reflect the action of the Z_3-group, which may be either trivial, i.e. abc=bca=cab, generalizing

Anjan Kundu

Formulating quantum integrability for nonultralocal models (NM) parallel to the familiar approach of inverse scattering method is a long standing problem. After reviewing our result regarding algebraic structures of ultralocal models, we look for the algebra underlying NM. We propose an universal equation represented by braided Yang-Baxter equation and able

Paolo Di Vecchia, Alberto Lerda, Lorenzo Magnea, Raffaele Marotta

We show how to obtain correctly normalized expressions for the Feynman diagrams of $Φ^3$ theory with an internal $U(N)$ symmetry group, starting from tachyon amplitudes of the open bosonic string, and suitably performing the zero--slope limit by giving an arbitrary mass $m$ to the tachyon. In particular we present explicit results for the two--loop amplitude

S. M. Barr

It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for doublet-triplet splitting can be implemented in $SU(5) \times SU(5)$ models, which requires no adjoint Higgs fields. This is an advantage from the point of view of string theory construction. Here the stability of the gauge hierarchy is examined in detail, and it is shown that it ca

M. Caffo, H. Czyz

BHAGEN-1PH is a FORTRAN program providing fast Monte Carlo event generation of the process $e^+ e^- \to e^+ e^- γ$, within electroweak theory, for both unpolarized beams and also for the longitudinally polarized electron beam. The program is designed for final leptons outside a small cone around the initial leptons direction and has a new algorithm allowing

R. Baier, Yu. L. Dokshitzer, A. H. Mueller, S. Peigné

The medium induced energy loss spectrum of a high energy quark or gluon traversing a hot QCD medium of finite volume is studied. We model the interaction by a simple picture of static scattering centres. The total induced energy loss is found to grow as $L^2$, where $L$ is the extent of the medium. The solution of the energy loss problem is reduced to the so

Bing An Li

Strong anomaly of the PCAC is found in $τ\rightarrowωππν$ and $ωρν$ in the chiral limit. It originates in WZW anomaly. Theoretical result of $τ\rightarrowωππν$ agrees with data well and the measurement of $τ\rightarrowωρν$ will confirm the strong anomaly of PCAC. The strong anomaly of PCAC is studied.

John F. Donoghue

I discuss some recent results on the systematic behavior of final state rescattering which makes use of the limit of a heavy B meson. The results suggest that soft final state interactions do not disappear in the large $m_B$ limit. Soft and hard final state phases can both contribute to CP violating asymmetries in B decay. The way that the soft phases occur

John F. Donoghue

The techniques of dispersion relations match very well with those of effective field theory. I describe the techniques for using dispersion relations effectively, and give some pedagogical examples to illustrate the range of applications.

Frank Close, Harry Lipkin

Hadron resonances affect nonexotic $D^o$ decays but not $B$ decays which are far from the resonance region. We obtain new information from {\bf exclusive} decays and show that interference between colour favoured and colour suppressed diagrams is {\bf constructive} in $B$ and (some) $D$ decays in contrast to the inclusive decays where a net Pauli destructive

M. Fabbrichesi

I review a recent attempt to reproduce the isospin $I= 0$ and 2 amplitudes for the decay of a kaon into two pions by estimating the relevant hadronic matrix elements in the chiral quark model. The results are parametrized in terms of the quark and gluon condensates and of the constituent quark mass $M$. The latter is a parameter characteristic of the model.

P. Nason, C. Oleari

We study the correlations of $b\bar b$ pairs produced in inclusive $Z^0$ decays, and their possible influence upon the determination of $R_b$.

I. M. Dremin

Oscillations of cumulant moments of multiplicity distributions at high ranks, evolution of factorial moments with bin sizes (intermittency, fractality), zeros of the truncated generating functions of multiplicity distributions, and charge fluctuations in multiparticle production processes are discussed.

R. Höpker, W. Beenakker

We present the cross-sections for the hadroproduction of squarks and gluinos in next-to-leading order of supersymmetric QCD. The four possible final states squark-antisquark, squark-squark, gluino-gluino and squark-gluino are analysed for the hadron colliders Tevatron and LHC. The dependence of the cross-sections on the renormalization and factorization scal

Gye T. Park

In the light of the top quark discovered very recently by CDF, we investigate the possibility of narrowing down the allowed top quark masses by combining for the first time only two strongest constraints present in the no-scale $SU(5)\times U(1)$ supergravity model, namely, the ones from the flavor-changing radiative decay $b\rightarrow sγ$ and the precision

R. Michael Barnett, Lawrence J. Hall

The CDF and D0 collaborations have both reported unusual events in the dilepton+jets sample with very high lepton and missing transverse energies. It is possible, but very unlikely, that these events originate from top quark pair production; however, they have characteristics that are better accounted for by decays of supersymmetric quarks with mass in the r

John F. Donoghue

In quantum field theory there is now a well developed technique, effective field theory, which allows one to obtain low energy quantum predictions in ``non-renormalizable'' theories, using only the degrees of freedom and interactions appropriate for those energies. Whether or not general relativity is truly fundamental, at low energies it is automati

P. Fraundorf

Motions with respect to one inertial (or ``map'') frame are often described in terms of the coordinate time/velocity pair (or ``kinematic'') of the map frame itself. Since not all observers experience time in the same way, other time/velocity pairs describe map-frame trajectories as well. Such coexisting kinematics provide alternate variables

Akhil Ranjan

In this paper we give a proof of Lichnerowicz Conjecture for compact simply connected manifolds which is intrinsic in the sense that it avoids the {\it Nice Embeddings} into eigen spaces of the Laplacian. Even if one wants to use these embeddings this paper gives a more streamlined proof.

A. Azhari, T. T. Truong

The possibility of describing quantum mechanical particles on a plane by a Jastrow wave function is studied. We obtain the condition under which the particles interact through pair potentials. It is found that if the interparticle forces depend only on distance, then only the attractive harmonic pair potential is consistent with the Jastrow ansatz. We discus

D. Shahar, D. C. Tsui, M. Shayegan, J. E. Cunningham

We have conducted an experimental study of the linear transport properties of the magnetic-field induced insulating phase which terminates the quantum Hall (QH) series in two dimensional electron systems. We found that a direct and simple relation exists between measurements of the longitudinal resistivity, $ρ_{xx}$, in this insulating phase and in the neigh

V. Subrahmanyam, Fajian Shi

The U=infinity Hubbard model on a hypercubic lattice with exactly one hole is studied. It is seen that a degeneracy can occur in the maximal-spin sector. It is proved variationally that the Nagaoka (maximal spin) state is not a ground state, if degeneracy exists. We give an explicit construction of a variational state, an incommensurate spin-wave state, with

C. O'Donovan, M. D. Lumsden, B. D. Gaulin, J. P. Carbotte

Within a microscopic two band model of planes and chains with a pairing potential in the planes and off diagonal pairing between planes and chains we find that the chains make the largest contribution to the Josephson tunnelling current and that through them the d-wave part of the gap contributes to the current. This is contrary to the usual assumption that

G. Tellez

The static and time-dependent potential and surface charge correlations in a plasma with a boundary are computed for different shapes of the boundary. The case of a spheroidal or spherical one-component plasma is studied in detail because experimental results are available for such systems. Also, since there is some knowlegde both experimental and theoretica

S. Moukouri, L. G. Caron

We show a strong indication of the existence of a large Fermi surface in the one-dimensional Kondo lattice model. The characteristic wave vector of the model is found to be $k_F=(1+ρ)π/2$, $ρ$ being the density of the conduction electrons. This result is at first obtained for a variant of the model that includes an antiferromagnetic Heisenberg interaction $J

M. W. Wu, H. L. Cui, W. Sun, S. Y. Wu

In this letter we clarify the role of heat flux in the hydrodynamic balance equations in 2D quantum wells, facilitating the formulation of an Onsager relation within the framework of this theory. We find that the Onsager relation is satisfied within the framework of the 2D hydrodynamic balance equation transport theory at sufficiently high density. The condi

Edward McCann, Igor V. Lerner

We consider a distribution of conductance fluctuations in quantum dots with single channel leads and continuous level spectra and we demonstrate that it has a distinctly non-Gaussian shape and strong dependence on time-reversal symmetry, in contrast to an almost Gaussian distribution of conductances in a disordered metallic sample connected to a reservoir by

Alain Arneodo, Jean-Philippe Bouchaud, Rama Cont, Jean-Francois Muzy

Recently, Ghashghaie et al. have shown that some statistical aspects of fully developed turbulence and exchange rate fluctuations exhibit striking similarities (Nature 381, 767 (1996)). The authors then suggested that the two problems might be deeply connected, and speculated on the existence of an `information cascade' which would play the role in finan

T. Sh. Misirpashaev, C. W. J. Beenakker

We study the statistics of the reflectance (the ratio of reflected and incident intensities) of an $N$-mode disordered waveguide with weak absorption $γ$ per mean free path. Two distinct regimes are identified. The regime $γN^2\gg1$ shows universal fluctuations. With increasing length $L$ of the waveguide, the variance of the reflectance changes from the val

T. Sh. Misirpashaev, J. C. J. Paasschens, C. W. J. Beenakker

An analytical and numerical study is presented of transmission of radiation through a multi-mode waveguide containing a random medium with a complex dielectric constant $ε= ε'+iε''$. Depending on the sign of $ε''$, the medium is absorbing or amplifying. The transmitted intensity decays exponentially $\propto\exp(-L/ξ)$ as the waveguide le

A. B. Kuklov, N. Chencinski, A. M. Levine, W. M. Schreiber

Single particle states in the atomic trap employing the rotating magnetic field are found using the full time-dependent instantaneous trapping potential. These states are compared with those of the effective time-averaged potential. We show that the trapping is possible when the frequency of the rotations exceeds some threshold. Slightly above this threshold

Todor Stanev

We study the deflection of ultra high energy cosmic ray protons in different models of the regular galactic magnetic field. Such particles have gyroradii well in excess of 1 kpc and their propagation in the galaxy reflects only the large scale structure of the galactic magnetic field. A future large experimental statistics of cosmic rays of energy above 10$^

A. D. Rogava, V. I. Berezhiani, S. M. Mahajan

Acoustic perturbations in a parallel relativistic flow of an inviscid fluid are considered. The general expression for the frequency of the sound waves in a uniformly (with zero shear) moving medium is derived. It is shown that relativity evokes a difference in the frequencies of the sound-type perturbations propagating along and against the current. Besides

Joachim Wambsganss, Renyue Cen, Guohong Xu, Jeremiah P. Ostriker

Weak gravitational lensing by large-scale structure affects the determination of the cosmological deceleration parameter $q_0$. We find that the lensing induced dispersions on truly standard candles are $0.04$ and $0.02$ mag at redshift $z=1$ and $z=0.5$, respectively, in a COBE-normalized cold dark matter universe with $Ω_0=0.40$, $Λ_0=0.6$, $H=65$km/s/Mpc

Simon P Goodwin

The results of N-body simulations of the expulsion of residual gas from young globular clusters are presented. Globular clusters with a variety of initial masses, Galactocentric radii, concentration and initial mass function slope with star formation efficiencies (SFEs) below 50% were investigated. The residual gas in the clusters was simply treated as an ex

Frank P. Pijpers

A common problem in astronomy is the determination of the time shift between two otherwise identical time series of measured flux from a variable source, in short the determination of a time lag. Two examples of where this problem occurs are in the determination of the Hubble constant from multiple images of gravitationally lensed variable quasars and also i

Deborah B. Haarsma, Jacqueline N. Hewitt, Joseph Lehár, Bernard F. Burke

We report on 15 years of VLA monitoring of the gravitational lens B0957+561 at 6 cm. Since our last report in 1992, there have been 32 additional observations, in which both images have returned to their quiescent flux density levels and the A image has brightened again. We estimate the time delay from the light curves using three different techniques: the c

R. D. McKeown

The strange magnetic moment of the nucleon ($μ_s$) is examined as part of the nucleon's isoscalar anomalous moment. The dominant up and down quark effects in the anomalous moment may actually tend to favor $μ_s >0$, which is contrary to the negative values that generally result from model calculations. The possible origins of this apparent discrepancy ar

A. Barros, C. Romero

The gravitational field of a global monopole in the context of Brans-Dicke theory of gravity is investigated. The space-time and the scalar field generated by the monopole are obtained by solving the field equations in the weak field approximation. A comparison is made with the corresponding results predicted by General Relativity.

Peter Orland

A distance function on the set of physical equivalence classes of Yang-Mills configurations considered by Feynman and by Atiyah, Hitchin and Singer is studied for both the $2+1$ and $3+1$-dimensional Hamiltonians. This set equipped with this distance function is a metric space, and in fact a Riemannian manifold as Singer observed. Furthermore, this manifold

Rafael Ramirez, Carlos P. Herrero, Emilio Artacho, Felix Yndurain

The problem of the low-energy highly-anharmonic quantum dynamics of isolated impurities in solids is addressed by using path-integral Monte Carlo simulations. Interstitial oxygen in silicon is studied as a prototypical example showing such a behavior. The assignment of a "geometry" to the defect is discussed. Depending on the potential (or on the imp

M. Prakash, S. Reddy, J. M. Lattimer, P. J. Ellis

A protoneutron star is formed immediately after the gravitational collapse of the core of a massive star. At birth, the hot and high density matter in such a star contains a large number of neutrinos trapped during collapse. Trapped neutrinos generally inhibit the presence of exotic matter -- hyperons, a kaon condensate, or quarks. However, as the neutrinos

Thomas Schmitt

Using a supergeometric interpretation of field functionals developed in previous papers, we show that for quite a large class of systems of nonlinear field equations with anticommuting fields, infinite-dimensional supermanifolds (smf) of classical solutions can be constructed. Such systems arise in classical field models used for realistic quantum field theo

Yuri N. Obukhov, Franz E. Schunck

The regular solutions for the Ginzburg-Landau (-Nielsen-Olesen) Abelian gauge model are studied numerically. We consider the static isolated cylindrically symmetric configurations. The well known (Abrikosov) vortices, which present a particular example of such solutions, play an important role in the theory of type II superconductors and in the models of str

S. S. Manna, D. Dhar

We relate the fractal dimension of the backbone, and the spectral dimension of Eden trees to the dynamical exponent z. In two dimensions, it gives fractal dimension of backbone equal to 4/3 and spectral dimension of trees equal to 5/4. In three dimensions, it provides us a new way to estimate z numerically. We get z=1.617 +/- 0.004.

Keiichi Akama, Takashi Hattori

We show that the compositeness condition for the induced gauge boson in the four-fermion interaction theory actually works beyond the one-loop approximation. The next-to-leading contributions are calculated, and turn out to be reasonably suppressed, so that the leading-order approximation is justified.

A. Gurtu, S. Mangla, A. Sopczak

This paper has been withdrawn.

P. Bagnaia, F. DiLodovico, J. -P. Ernenwein, R. Faccini

This paper has been withdrawn.

K. L. Vaninsky

The Dirac operator enters into zero curvature representation for the cubic nonlinear Schrödinger equation. We introduce and study a conformal map from the upper half-plane of the spectral parameter of the Dirac operator into itself. The action variables turn out to be limiting boundary values of the imaginary part of this map. We describe the image of the mo

Wen-Xiu MA, Zi-Xiang ZHOU

An isospectral hierarchy of commutative integrable systems associated with a polynomial spectral problem is proposed. The resulting hierarchy possesses a recursion structure controlled by a hereditary operator. The nonisospectral flows generate the time first order dependent symmetries of the isospectral hierarchy, which constitute Virasoro symmetry algebras

Jonathan Rosenberg

Quantization, at least in some formulations, involves replacing some algebra of observables by a (more non-commutative) deformed algebra. In view of the fundamental role played by K-theory in non-commutative geometry and topology, it is of interest to ask to what extent K-theory remains "rigid" under this process. We show that some positive results c

K. Hara, G. A. Lalazissis

A method is proposed and tested for the analysis of Delta I=2 staggering observed in nuclear rotational bands. We examine six super- and hyper-deformed bands, among which that of 149Gd and possibly of 147Gd seem to exhibit real staggering. However, we emphasize that the presence of staggering may not necessarily imply the occurrence of bifurcation. It is als

Josef Sollfrank, Pasi Huovinen, Markku Kataja, P. V. Ruuskanen

We study relativistic S+Au collisions at 200 A GeV/c using a hydrodynamical approach. We test various equations of state (EOSs), which are used to describe the strongly interacting matter at densities attainable in the CERN-SPS heavy ion experiments. For each EOS, suitable initial conditions can be determined to reproduce the experimental hadron spectra; thi

S. A. Sofianos, S. A. Rakityansky

We propose an exact method for locating the zeros of the Jost function for analytic potentials in the complex momentum--plane. We further extend the method to the complex angular--momentum plane to provide the Regge trajectories. It is shown, by using several examples, that highly accurate results for extremely wide as well as for extremely narrow resonances

S. A. Rakityansky, S. A. Sofianos, L. L. Howell, M. Braun

The nuclear reaction e+p+d -----> He3 + e is considered at thermonuclear energies. The motion of the electron is treated within the adiabatic approximation and the pd scattering state is constructed in the form of an antisymmetrized product of the bound state wave function of the deuteron and of the wave function of the pd relative motion. The latter is calc

U. van Kolck, G. A. Miller, D. O. Riska

Short range meson-exchange mechanisms such as $ρ\toωπ^0$ contribute significantly to the amplitude for $pp\rightarrow ppπ^0$ near threshold in addition to pion rescattering. The uncertainty of the latter contribution, which depends on poorly determined parameters, is estimated. Allowing for this uncertainty and taking the short range meson-exchange contribut