September 1995 arXiv papers — page 11

Michael R. Garcia, Paul J. Callanan, Jeffrey E. McClintock, Ping Zhao

We present results obtained from a series of 5~Å resolution spectra of the X-ray Nova GRO~J0422+32 obtained in 1993~October, when the system was approximately 2 magnitudes above quiescence, with ${\rm R \sim 19}$. The data were obtained in an effort to measure the orbital radial velocity curve of the secondary, but detection of the narrow photospheric absorp

M. Balucinska-Church, T. Belloni, M. J. Church, G. Hasinger

We present results of a study of the soft X-ray excess in the black hole candidate Cygnus X-1 made with the {\it Rosat PSPC}, using observations taken during persistent emission at orbital phases close to 0.5. The soft excess can be well fitted as a blackbody with temperature $\rm {kT_{bb}}$ = $\rm {0.13\pm 0.02}$ keV. $\rm {kT_{bb}}$ did not vary appreciabl

Nick Kaiser

In this review I will describe progress that has been made in determining masses of galaxy clusters using `weak lensing' and how this technique my be applied in the future to determine the dark matter distribution both on supercluster scales and on the scale of galaxy haloes.

Tetsuya Shiromizu, Masahiro Morikawa, Jun'ichi Yokoyama

We derivate the Langevin and the Fokker-Planck equations for the radius of $O(3)$-symmetric subcritical bubbles as a phenomenological model to treat thermal fluctuation. The effect of thermal noise on subcritical bubbles is examined. We find that the fluctuation-dissipation relation holds and that in the high temperature phase the system settles down rapidly

Arvind, N. Mukunda

The non-classical property of subpoissonian photon statistics is extended from one to two-mode electromagnetic fields, incorporating the physically motivated property of invariance under passive unitary transformations. Applications to squeezed coherent states, squeezed thermal states, and superposition of coherent states are given. Dependences of extent of

J. Rembielinski

Quantum field theory of space-like particles is investigated in the framework of absolute causality scheme preserving Lorentz symmetry. It is shown that tachyons are associated with unitary orbits of Poincaré mappings induced from SO(2) little group instead of SO(2,1) one. Therefore the corresponding elementary states are labelled by helicity. A particular c

J. Rembielinski

A consistent quantization scheme for imaginary-mass field is proposed. It is related to an appropriate choice of the synchronization procedure (definition of time), which guarantee an absolute causality in agreement with Lorentz covariance. In that formulation a possible existence of field excitations (tachyons) distinguish an inertial frame (tachyon privile

Dennis Zaritsky, Stephen A. Shectman, Gregory Bredthauer

We discuss the design, construction, and use of a new class of scanning camera that eliminates a critical limitation of standard CCD drift-scan observations. A standard scan, which involves no correction for the differential drift rates and curved stellar paths across the field-of-view, suffers from severe image degradation even when one observes at moderate

Wei Wang, Shaojin Qin, Zhong-Yi Lu, Lu Yu

An impurity bond $J{&#39;}$ in a periodic 1D antiferromagnetic, spin 1 chain with exchange $J$ is considered. Using the numerical density matrix renormalization group method, we find an impurity energy level in the Haldane gap, corresponding to a bound state near the impurity bond. When $J{&#39;}<J$ the level changes gradually from the edge of the Haldane ga

F. M. Renard, C. Verzegnassi

We calculate, using a Z-peak subtracted representation of four-fermion processes previously illustrated for the case of electron-positron annihilation into charged lepton-antilepton, the corresponding expressions of the new physics contributions for the case of final quark-antiquark states, allowing the possibility of both universal and non universal effects

T. Csorgo, B. Lorstad

The parameters of the Bose-Einstein correlation function may obey an {\it $M_t$-scaling}, as observed in $S + Pb$ and $Pb + Pb$ reactions at CERN SPS. This $M_t$-scaling implies that the Bose-Einstein correlation functions view only a small part of the big and expanding system. The full sizes of the expanding system at the last interaction are shown to be me

P. J. Forrester

Using the ground state $ψ_0$ of a multicomponent generalization of the Calogero-Sutherland model as a weight function, orthogonal polynomials in the coordinates of one of the species are constructed. Using evidence from exact analytic and numerical calculations, it is conjectured that these polynomials are the Jack polynomials $J_κ^{(1+1/λ)}$, where $λ$ is t

J. Gomis, K. Kamimura, J. M. Pons, F. Zamora

One loop anomalies and their dependence on antifields for general gauge theories are investigated within a Pauli-Villars regularization scheme. For on-shell theories {\it i.e.}, with open algebras or on-shell reducible theories, the antifield dependence is cohomologically non trivial. The associated Wess-Zumino term depends also on antifields. In the classic

Vadim B. Kuznetsov

Hidden symmetry of the quantum Calogero-Moser system with the inverse-square potential is explicitly demonstrated in algebraic sense. We find the underlying algebra explaining the super-integrability phenomenon for this system. Applications to related multi-variable Bessel functions are also discussed.

R. A. Arndt, I. I. Strakovsky, R. L. Workman

We present the results of an energy-dependent and set of single-energy partial-wave analyses of single-pion photoproduction data. These analyses extend from threshold to 2 GeV in the laboratory photon energy, and update our previous analyses to 1.8 GeV. Photo-decay amplitudes are extracted for the baryon resonances within this energy range. We consider two p

Toshiki Maruyama, Koji Niita, Akira Iwamoto

In order to treat low-energy heavy-ion reactions, we make an extension of quantum molecular dynamics method. A phenomenological Pauli potential is introduced into effective interactions to approximate the nature of the Fermion many-body system. We treat the widths of nucleon wave-packets as time-dependent dynamical variables. With these modifications, our mo

W. A. Sabra, S. Thomas, N. Vanegas

Target space duality symmetries, which acts on Kähler and continuous Wilson line moduli, of a ${\bf Z}_N$ ($N\not=2$) 2-dimensional subspace of the moduli space of orbifold compactification are modified to include twisted moduli. These spaces described by the cosets $SU(n,1)\over SU(n)\times U(1)$ are $special$ Kähler, a fact which is exploited in deriving t

Amit Giveon, Oskar Pelc, Eliezer Rabinovici

A family of solvable self-dual Lie algebras that are not double extensions of Abelian algebras and, therefore, cannot be obtained through a Wigner contraction, is presented. We construct WZNW and gauged WZNW models based on the first two algebras in this family. We also analyze some general phenomena arising in such models.

M. Chaichian, M. Hayashi

The evolution of QCD coupling constant at finite temperature is considered by making use of the finite temperature renormalization group equation up to the one-loop order in the background field method with the Feynman gauge and the imaginary time formalism. The results are compared with the ones obtained in the literature. We point out, in particular, the o

Carl Carlson, Greg Dorata, David Morgan, Marc Sher

In a class of supergravity models, the gluino and photino are massless at tree level and receive small masses through radiative corrections. In such models, one expects a gluino-gluon bound state, the $R_0$, to have a mass of between 1.0 and 2.2 GeV and a lifetime between $10^{-10}$ and $10^{-6}$ seconds. Applying peturbative QCD methods (whose validity we d

Herbert Nachbagauer

We study field configurations in a hot quark-gluon plasma with spherical symmetry. We show that the electric fields point into radial direction and solve the effective non-abelian equations of motions. The corresponding charge density has a localized contribution which has a gauge invariant interpretation as a pointlike color charge. We discuss configuration

D. Toublan

The contributions of the lightest tensor-meson resonances to the low-energy coupling constants of second order chiral perturbation theory with two flavours are evaluated and compared with the available phenomenological information as well as with similar results for other resonances.

F. M. Renard

We present a set of studies concerning the description of New Physics (NP) effects caracterized by a scale much higher than the electroweak scale. We show that both present experimental results and several types of theretical considerations about the Standard Model (SM) and NP suggest a hierarchy among the sectors in which NP manifestations should appear. We

B. Lorstad

Most boson emitting sources contain a core of finite dimensions surrounded by a large halo, due to long-lived resonances like $ω,η,η&#39;,K^{0}$ etc. When the Bose-Einstein correlation (BEC) function of the core can be determined we show that its intercept ($λ$) measures, as a function of momentum, the square of the fraction of core particles produced. A sim

S. Catterall J. Kogut, R. Renken, G. Thorleifsson

We measure numerically the distribution of baby universes in the crumpled phase of the dynamical triangulation model of 4d quantum gravity. The relevance of the results to the issue of an exponential bound is discussed. The data are consistent with the existence of such a bound.

E. Recami, F. Raciti, W. A. Rodrigues, V. T. Zanchin

We present here a panoramic view of our unified, bi--scale theory of gravitational and strong interactions [which is mathematically analogous to the last version of N.Rosen&#39;s bi--metric theory; and yields physical results similar to strong gravity&#39;s]. This theory, developed during the last 15 years, is purely geometrical in nature, adopting the metho

Henk W. J. Blöte, Erik Luijten, Jouke R. Heringa

We investigate three Ising models on the simple cubic lattice by means of Monte Carlo methods and finite-size scaling. These models are the spin-1/2 Ising model with nearest-neighbor interactions, a spin-1/2 model with nearest-neighbor and third-neighbor interactions, and a spin-1 model with nearest-neighbor interactions. The results are in accurate agreemen

Y. Ohta, A. Nakauchi, R. Eder, K. Tsutsui

An exact-diagonalization technique on small clusters is used to study low-lying excitations and superconductivity in the two-dimensional negative-$U$ Hubbard model. We first calculate the Bogoliubov-quasiparticle spectrum, condensation amplitude, and coherence length as functions of the coupling strength $U/t$, thereby working out how the picture of Bogoliub

C. M. Canali

We consider a family of random matrix ensembles (RME) invariant under similarity transformations and described by the probability density $P({\bf H})= \exp[-{\rm Tr}V({\bf H})]$. Dyson&#39;s mean field theory (MFT) of the corresponding plasma model of eigenvalues is generalized to the case of weak confining potential, $V(ε)\sim {A\over 2}\ln ^2(ε)$. The eige

U. Pustogowa, T. A. Luce, W. Hubner, K. H. Bennemann

Nonlinear magneto-optics is a very sensitive fingerprint of the electronic, magnetic, and atomic structure of surfaces, interfaces, and thin ferromagnetic films. Analyzing theoretically the nonlinear magneto-optical Kerr effect for thin films of Fe(001) and at Fe surfaces we demonstrate exemplarily how various electronic material properties of ferromagnets ,

O. P. Sushkov

Ground state wave function of two-dimensional t-J model is found at doping close to half filling. It is shown that the condensation of Cooper pairs (superconducting pairing of mobile holes) and the condensation of spin-waves into spin-liquid state are closely connected. The effective spectrum of $S=1$ excitations, spin-wave gap pseudo-gap $Δ_M$, magnetic cor

Norman Margolus

Conventional computers are ill suited to run CA models, and so discourage their development. By creating a hardware platform that makes a broad range of new CA algorithms practical for real applications, we hope to whet the appetite of researchers for the astronomical computing power that can be harnessed in microphysics in a CA format.

Priyamvada Natarajan

We report the results of an attempt to study the velocity structure of the core of the cluster A2218 in order to probe its dynamical state. The aim is to understand if the core is indeed virialized? relaxed? or in hydrodynamic equilibrium? We use cluster lensing data in conjunction with the optical galaxy data to solve in detail for the nature of galaxy orbi

O. Almaini, B. J. Boyle, R. E. Griffiths, T. Shanks

We report the discovery of a high redshift, narrow emission-line galaxy identified in the optical follow-up of deep ROSAT fields. The object has a redshift of z=2.35 and its narrow emission lines together with its high optical and X-ray luminosity imply that this is a rare example of a type 2 QSO. The intrinsic X-ray absorption is either very low or we are o

Michael Platzoeder, Thomas Buchert

A new method for the statistical analysis of 3D point processes, based on the family of Minkowski functionals, is explained and applied to modelled galaxy distributions generated by a toy-model and cosmological simulations of the large-scale structure in the Universe. These measures are sensitive to both, geometrical and topological properties of spatial pat

M. A. Treyer, O. Lahav

We present a formalism describing the physical content of cross-correlation functions between a diffuse background and a population of discrete sources. The formalism is used to interpret cross-correlation signals between the unresolved X-ray background and a galaxy population resolved to high redshift in another spectral band. Specifically, we apply it to t

Dongsu Ryu, Jeremy Goodman, Ethan T. Vishniac

Tidally distorted accretion disks in binary star systems are subject to a local hydrodynamic instability which excites $m=1$ internal waves. This instability is three dimensional and approximately incompressible. We study the global aspects of this local instability using equations derived under the shearing sheet approximation, where the effects of the azim

Norman Gray, John C Brown

Thermal conduction across a magnetic field is strongly suppressed compared with conduction along the field. However, if a flare is heated by a highly filamented beam directed along the field, then the array of heated cells in a cross-section of the flare will result in both small spatial scales (with consequently large temperature gradients) and a large surf

John Dubinski, J. Christopher Mihos, Lars Hernquist

We use simulations of merging galaxies to explore the sensitivity of the morphology of tidal tails to variations of the halo mass distributions in the parent galaxies. Our goal is to constrain the mass of dark halos in well-known merging pairs. We concentrate on prograde encounters between equal mass galaxies which represent the best cases for creating tidal

R. Pandharipande

D. Abramovich found an error in the singularity analysis in the first posting of this paper affecting one formula (Thanks Dan).The error has been corrected. Only the arithmetic genus formula has changed. The geometric genus and all the canonical class formulas are the same.

I. Antoniadis, H. Partouche

We describe an $N=2$ heterotic superstring model of rank-3 which is dual to the type-II string compactified on a Calabi-Yau manifold with Betti numbers $b_{1,1}=2$ and $b_{1,2}=86$. We show that the exact duality symmetry found from the type II realization contains the perturbative duality group of the heterotic model, as well as the exact quantum monodromie

Greg Anderson, Diego Castano

Experimental searches for supersymmetry are entering a new era. As future experiments explore the mass range above the current lower bounds on superpartner masses, a failure to observe signals of superpartner production will begin to erode the central motivation for supersymmetry at the weak scale. In this article we present a detailed examination of which r

Giampiero Esposito

The problem of a rigorous theory of singularities in space-times with torsion is addressed. We define geodesics as curves whose tangent vector moves by parallel transport. This is different from what other authors have done, because their definition of geodesics only involves the Christoffel connection, though studying theories with torsion. We propose a pre

Andrew Gould

Pixel lensing, gravitational microlensing of unresolved stars, is potentially much more sensitive and much more widely applicable than is generally recognized. I give explicit expressions for the pixel noise induced by a time-variable PSF, by photometric and geometric misalignment, and by discrete pixelization, and I show that these can all be reduced below

F. Cardarelli, I. Grach, I. Narodetskii, G. Salme&#39;

The form factors of the $πρ$ and $πω$ radiative transitions are evaluated within a light-front constituent quark model, using for the first time the eigenfunctions of a light-front mass operator reproducing the meson mass spectrum and including phenomenological Dirac and Pauli quark form factors in the one-body electromagnetic current operator. The sensitivi

José Pantoja, Jorge Soto-Andrade

We construct, by contraction of a suitable complex vector bundle, the Weil representation of the finite symplectic group $Sp(A)$. We give an explicit description of the space of all lagrangian subspaces, which we use to compute the cocycle of our representation in terms of a geometric Gauss sum. We recover in this way previously constructed generalized Weil

Darwin Chang, We-Fu Chang

We investigate two methods of obtaining exactly solvable potentials with analytic forms.

Carlo Gobbi, Carlos L. Schat, Norberto N. Scoccola

A detailed calculation of electric and magnetic static polarizabilities of octet hyperons is presented in the framework of the bound state soliton model. Both seagull and dispersive contributions are considered, and the results are compared with different model predictions.

Douglas O. Carlson, C. -P. Yuan

We show that the production rate of the single-top quark event from the $W$-gluon fusion process is sensitive to new physics which strongly modifies the interactions of the top quark. The measurement of its production rate gives the partial decay width of the top quark which combined with the branching ratio measurement from the $t \bar t$ pair event determi

H1-collaboration

We present a new measurement of the total photoproduction cross section performed with the H1 detector at HERA. For an average centre of mass energy of 200~GeV a value of $σ_{tot}^{γ{p}}= 165\pm2\pm11μ$b has been obtained. A detailed analysis of the data in adequate kinematic regions enabled a decomposition of the total cross section in its elastic, single d

Giampiero Esposito, Giovanni Platania

We prove that in the Hartle-Hawking approach to quantum cosmology the existence of an inflationary phase is a general property of minisuperspace models given by a closed Friedmann-Robertson-Walker universe containing a massless scalar field with a $λϕ^{n}$ self-interaction. The evolution in time of the cosmic scale factor and of the scalar field in the very

Leticia F. Cugliandolo, Jorge Kurchan, Pierre Le Doussal

We study the out of equilibrium dynamics of an elastic manifold in a random potential using mean-field theory. We find two asymptotic time regimes: (i) stationary dynamics, (ii) slow aging dynamics with violation of equilibrium theorems. We obtain an analytical solution valid for all large times with universal scalings of two-time quantities with space. A no

Thierry Giamarchi, Pierre Le Doussal

We apply the gaussian variational method (GVM) to study the equilibrium statistical mechanics of the two related systems: (i) classical elastic manifolds, such as flux lattices, in presence of columnar disorder correlated along the $τ$ direction (ii) interacting quantum particles in a static random potential. We find localization by disorder, the localized p

D. I. Novikov, H. E. Jorgensen

In this paper we develop the theory of clusterization of peaks in a Gaussian random field. We have obtained new mathematical results from this theory and the theory of percolation and have proposed a topological method of analysis of sky maps based on these results. We have simulated $10^o\times10^o$ sky maps of the cosmic microwave background anisotropy exp

Jorge Pullin

Contents: -Report from the APS Topical Group in Gravitation, Beverly Berger -Some remarks on the passing of S. Chandrasekhar, Robert Wald -LIGO Project Status, Syd Meshkov and Stan Whitcomb -New Hyperbolic forms of the Einstein Equations, Andrew Abrahams -Massless Black Holes, Gary Horowitz -A plea for theoretical help from the gravity wave co-op, William Ha

G. M. Gandenberger, N. J. MacKay, G. M. T. Watts

We construct new $U_q(a^{(2)}_{2n-1})$ and $U_q(e^{(2)}_6)$ invariant $R$-matrices and comment on the general construction of $R$-matrices for twisted algebras. We use the former to construct $S$-matrices for $b^{(1)}_n$ affine Toda solitons and their bound states, identifying the lowest breathers with the $b^{(1)}_n$ particles.

F. A. Dilkes, D. G. C. McKeon

The DeWitt expansion of the matrix element $M_{xy} = \left\langle x \right| \exp -[\case{1}{2} (p-A)^2 + V]t \left| y \right\rangle$, $(p=-i\partial)$ in powers of $t$ can be made in a number of ways. For $x=y$ (the case of interest when doing one-loop calculations) numerous approaches have been employed to determine this expansion to very high order; when $

Barry M. McCoy, William P. Orrick

We study the perturbation theory for the general non-integrable chiral Potts model depending on two chiral angles and a strength parameter and show how the analyticity of the ground state energy and correlation functions dramatically increases when the angles and the strength parameter satisfy the integrability condition. We further specialize to the superin

Ahmed Hindawi, Burt A. Ovrut, Daniel Waldram

A discussion of the number of degrees of freedom, and their dynamical properties, in higher derivative gravitational theories is presented. The complete non-linear sigma model for these degrees of freedom is exhibited using the method of auxiliary fields. As a by-product we present a consistent non-linear coupling of a spin-2 tensor to gravitation. It is sho

Brian Harbourne

By defining a fat point subscheme of $P^2$ to be a 0-dimensional subscheme defined by a sheaf of integrally closed ideals one extends the notion of fat point subschemes to allow infinitely near points. With this notion of fat points, this preprint determines the number of generators in each degree in a minimal homogeneous set of generators for the homogeneou

Brian Harbourne

A determination of the fixed components, base points and irregularity is made for arbitrary numerically effective divisors on any smooth projective rational surface having an effective anticanonical divisor. All of the results are proven over an algebraically closed field of arbitrary characteristic. Applications, treated in separate papers, include question

Daniel M. Kaplan

I review the sensitivities achieved by and projected for fixed-target charm experiments in CP violation, flavor-changing neutral-current and lepton-number-violating decays, and mixing, and I describe the Charm2000 experiment intended to run at Fermilab in the Year ~2000. If approved, Charm2000 will in many of these areas exceed the sensitivities projected fo

Mohammad R. Garousi

We demonstrate that the technique of abelian bosonization through duality transformations can be extended to gauging anomalous symmetries. The example of a Dirac fermion theory is first illustrated. This idea is then also applied to bosonize a chiral fermion by gauging its chiral phase symmetry.

J. G. Congleton, E. Truhlik

Exchange current corrections are calculated using currents found from the hard-pion model and AV14+3BF wavefunctions. Results are given for the rate and spin observables. Their sensitivity to g_P, the nucleon pseudoscalar form factor, is reported.

Neelima G. Kelkar, B. K. Jain

The triton energy spectra of the charge-exchange $^{12}$C($^3$He,t) reaction at 2 GeV beam energy are analyzed in the quasi-elastic nucleon knock-out region. Considering that this region is mainly populated by the charge-exchange of a proton in $^3$He with a neutron in the target nucleus and the final proton going in the continuum, the cross-sections are wri

Sy D. Friedman, W. Hugh Woodin

We show that the supremum of the lengths of boldface Delta-1-2 prewellorderings of the reals can be Aleph-2, with Aleph-1 inac- cessible to reals, assuming only the consistency of an inaccessible.

Sy D. Friedman

We present a proof of Jensen&#39;s Coding Theorem (assumong -0#) which quotes the covering lemma, but otherwise makes no appeal to fine structure theory. The key idea is to use a modified definition of the coding at limit cardinals, using &#34;coding delays&#34;.

Sy D. Friedman

We show that an inner model of a class-generic extension of L need not itself be such an extension. Our example is of the form L[R], where R is a real belonging to a class-generic extension of L and constructible from 0#.

Paola Giacconi, Fabio Maltoni, Roberto Soldati

A general expression for the scattering amplitude of nonrelativistic spinless particles in the Aharonov-Bohm gauge potential is obtained within the time independent formalism. The result is valid also in the backward and forward directions as well as for any choice of the boundary conditions on the wave function at the flux tube position.

Jouko Mickelsson

These notes explain recent developments concerning chiral anomalies and hamiltonian quantization, their relation to the theory of gerbes, and extensions of generalized loop algebras using the residue calculus of pseudodifferential operators. The renormalization of the Dirac field, leading to Schwinger terms in equal time commutation relations, is treated in

L. Chekhov

We give the description of discretized moduli spaces (d.m.s.) $\Mcdisc$ introduced in \cite{Ch1} in terms of discrete de Rham cohomologies for moduli spaces $\Mgn$. The generating function for intersection indices (cohomological classes) of d.m.s. is found. Classes of highest degree coincide with the ones for the continuum moduli space $\Mc$. To show it we u

Eric Braaten

Recent data from the Tevatron have revealed that the production rate of prompt charmonium is more than an order of magnitude larger than the best theoretical predictions of a few years ago. This surprising result can be understood by taking into account new production mechanisms that include fragmentation and the formation of charmonium from color-octet $c \

C. -P. Yuan

We discuss physics of the top quark at the Fermilab Tevatron. By the year 2000, many properties of the top quark can be measured at the Tevatron.

P. H. Chankowski, S. Pokorski

The bounds on the Higgs mass in the Standard Model are re-analyzed using the precision electroweak data presented at the International Europhysics Conference on High Energy Physics, Brussels, 27 July -- 2 August, 1995

David Summers, Dieter Zeppenfeld

Gluon bremsstrahlung in scattering events with high transverse momentum jets is expected to increase markedly with the hardness (sum E_T) of the primary event. Within perturbative QCD we estimate a probability of order unity to see additional minijets with E_T >~ 15 GeV in ``dijet&#39;&#39; events with sum E_T > 400 GeV. The veto of such minijets is a promis

B. C. Allanach, S. F. King

We consider the problem of neutrino masses and mixing angles in a supersymmetric model based on the gauge group SU(4)$\otimes$SU(2)$_L\otimes$SU(2)$_R$ broken at the scale $M_X\approx 10^{16}$ GeV. We extend a previous operator analysis of the charged lepton and quark masses and mixing angles in this model to include the neutrino sector, assuming a universal

Robert Fleischer

Using the $SU(3)$ flavour symmetry of strong interactions, we propose strategies for extracting both the CKM-angle $γ$ and the $\bar b\to\bar uu\bar s$ tree-level amplitude $T&#39;$. We present also an approximate approach using the branching ratios for the modes $B^+\toπ^+ K^0$, $B^0_d\toπ^- K^+$, $\bar B^0_d\toπ^+ K^-$ and $B^+\toπ^+π^0$ which should be ra

A. G. Akeroyd

Charged Higgs scalars light enough to contribute to top quark decays are possible in various non--minimal Higgs models. We show that such a decay would be consistent with the current Tevatron data, and will remain hidden until a larger luminosity can be achieved.

J. Manjavidze

The paper contains description of the path integrals in the action-angle phase space. It allows to split the action and angle degrees of freedom and to show that the angular quantum corrections cancel each other if the classical classical trajectory is periodic. The example considered in the paper shows that the quantum problem can be quasiclassical over the

T. Hotta, K. -I. Izawa, T. Yanagida

We consider a supersymmetric hypercolor gauge theory with six flavors of quarks interacting strongly at the grand unification scale. This model solves the most serious problem -- doublet-triplet splitting in the grand unified theories. We also show that the dangerous dimension-five operators for nucleon decays are suppressed simultaneously, which makes our m

Mark Fischler, Mike Uchima

The Cray T3D, an MIMD system with NUMA shared memory capabilities and in principle very low communications latency, can support the Canopy framework for grid-oriented applications. CANOPY has been ported to the T3D, with the intent of making it available to a spectrum of users. The performance of the T3D running Canopy has been benchmarked on five QCD applic

Thomas C. Blum, James E. Hetrick, Doug Toussaint

We study lattice QCD in the limit that the quark mass and chemical potential are simultaneously made large, resulting in a controllable density of quarks which do not move. This is similar in spirit to the quenched approximation for zero density QCD. In this approximation we find that the deconfinement transition seen at zero density becomes a smooth crossov

S. T. West, J. F. Wheater

A study is made of some properties of this interface in the SU(3) pure gauge theory in 2+1 dimensions. At high temperatures, the interface tension is measured and shows agreement with the perturbative prediction. Near the critical temperature, the behaviour of the interface is examined, and its fluctuations compared to a scalar field theory model.

Akio Hosoya, Shiho Kobayashi

We discuss the Anderson localization of electromagnetic fields in the fluctuating plasma induced by the gravitational density perturbation before the recombination time of the Universe. Randomly distributed localized coherent electromagnetic fields emerge in the thermal equilibrium before the recombination time. We argue that the localized coherent electric

H. Suzuki, E. Takasugi

The evaluation of the absorption coefficients are important for particle emission caused by Hawking radiation. In the case of cosmological particle emission from the event horizon in De Sitter space, it is known that the scalar wave functions are solved in terms of Legendre functions. For fields with higher spin, the solution has been examined with low frequ

H. Suzuki, E. Takasugi, Y. Takayama

New classes of classically integrable models in the cosmological theories with a scalar field are obtained by using freedoms of defining time and fields. In particular, some models with the sum of exponential potentials in the flat spatial metric are shown to be integrable. The model with the Sine-Gordon potential can be solved in terms of analytic continuat

Pavel Exner

The known correspondence between the Kronig-Penney model and certain Jacobi matrices is extended to a wide class of Schroedinger operators on graphs. Examples include rectangular lattices with and without a magnetic field, or comb-shaped graphs leading to a Maryland-type model.

Pavel Exner

We consider a quantum mechanical particle living on a graph and discuss the behaviour of its wavefunction at graph vertices. In addition to the standard (or delta type) boundary conditions with continuous wavefunctions, we investigate two types of a singular coupling which are analogous to the delta&#39; interaction and its symmetrized version for particle o

L. P. Rokhinson, B. Su, V. J. Goldman

We have studied the temperature dependence of diagonal conductivity in high-mobility two-dimensional samples at filling factors $ν=1/2$ and 3/2 at low temperatures. We observe a logarithmic dependence on temperature, from our lowest temperature of 13 mK up to 400 mK. We attribute the logarithmic correction to the effects of interaction between composite ferm

Joel Feldman, Manfred Salmhofer, Eugene Trubowitz

The perturbation expansion for a general class of many-fermion systems with a non-nested, non-spherical Fermi surface is renormalized to all orders. In the limit as the infrared cutoff is removed, the counterterms converge to a finite limit which is differentiable in the band structure. The map from the renormalized to the bare band structure is shown to be

M. Serva, G. Paladin, J. Raboanary

We perform a duality transformation that allows one to express the partition function of the d-dimensional Ising model with random nearest neighbor coupling in terms of new spin variables defined on the square plaquettes of the lattice. The dual model is solved in the mean field approximation.

E. Hofstetter, J. M. C. Taylor, A. MacKinnon

We have developed new methods to calculate dispersion curves (analytically in the simpler cases) from which we are able to derive the spatial distribution of electron and current densities. We investigate the case where the magnetic field varies linearly with position and the results provide useful insights into the properties of this and other field distrib

M. Caselle

We discuss the connection between the random matrix approach to disordered wires and the Calogero-Sutherland models. We show that different choices of random matrix ensembles correspond to different classes of CS models. In particular, the standard transfer matrix ensembles correspond to CS model with sinh-type interaction, constructed according to the $C_n$

Michael E. Flatte&#39;, Jeff M. Byers

We consider a scanning tunneling microscope (STM) such that tunneling occurs through two atomically sharp protrusions on its tip. When the two protrusions are separated by at least several atomic spacings, the differential conductance of this STM depends on the electronic transport in the sample between the protrusions. Furthermore two-protrusion tips common

E. V. Tsiper

Optical properties of large arrays of isolated quantum dots are discussed in order to interpret the existent photoluminescence data. The presented theory explains the large observed shift between the lowest emission and absorption energies as the average distance between the ground and first excited states of the dots. The lineshape of the spectra is calcula

Rosemary F. G. Wyse, Gerard Gilmore

The immediate Solar neighborhood should be a fair sample of the local Galaxy. However, the chemical abundance distribution of long-lived disk stars very near the Sun contains a factor of five to ten more metal-poor stars, $-1 \simlt {\rm [Fe/H]} \simlt -0.4$ dex, than is consistent with modern star-count models of larger scale Galactic structure. The metalli

M. Ruffert, H. -Th. Janka, G. Schaefer

We investigate the dynamics and evolution of coalescing neutron stars. Although the code (Piecewise Parabolic Method) is purely Newtonian, we do include the emission of gravitational waves and their backreaction on the hydrodynamic flow. The properties of neutron star matter are described by the physical equation of state of Lattimer \& Swesty (1991). Energy

T. Buchert

The present lecture notes address three columns on which the Lagrangian perturbation approach to cosmological dynamics is based: 1. the formulation of a Lagrangian theory of self--gravitating flows in which the dynamics is described in terms of a single field variable; 2. the procedure, how to obtain the dynamics of Eulerian fields from the Lagrangian pictur

J. P. Lasota, J. M. Hameury, J. M. Hure

We show that if the inner regions of accretion discs in quiescent dwarf nova systems are removed by magnetic disruption or evaporated by siphon flows, the remaining disc is globally stable for mass transfer rates $\lta 10^{15}$ g s$^{-1}$. This implies that (super)outbursts in these systems have to be triggered by an enhanced mass transfer form the companion

J. P. Lasota

Models of Soft X--ray Transients are presented and compared with observations. The importance of inner advection--dominated flows in quiescent transient sources is discussed, as well as the problem of global stability of the standard outer accretion disc. A comparison is made with similar problems in dwarf nova models.