April 1996 arXiv papers — page 9

Zuo-tang Liang

Characteristics of the available data are briefly summarized. Different theoretical approaches are reviewed with special attention to a non-perturbative model which explicitly takes the orbital motion of the valence quarks into account. The connection between such asymmetries and hyperon polarization in unpolarized reactions is discussed.

Kakali Roy-Maity, Padmanabha Dasgupta

Evolution of structure functions is studied in a chiral potential model which incorporates the pion as the chiral symmetry restoring field. Evolution equations for the quark and pion densities are derived in the lowest order at large $Q^2$. The splitting function for quark emission from point-like pion is flavor-dependent. This is shown to lead to nontrivial

M. Thunman

New physics can be searched for in deep inelastic scattering experiments. New phenomena, like additional production mechanisms for heavy quarks, manifest themselves through production and decays of short-lived hadrons, which give additional muons in their decays. Muons from decays of light mesons can then be a severe background, especially at fixed target ex

G. Ingelman, M. Thunman

The prospects to test the hypothesis of intrinsic charm quarks in the proton are investigated. We consider how this component can be directly or indirectly probed in deep inelastic scattering at HERA and in fixed target experiments and find that an overlooked signal might be present in existing NMC data. Applying the intrinsic charm model to hadron collision

G. Ingelman, M. Thunman

The flux of neutrinos originating from cosmic ray interactions with matter in the Sun has been calculated based on Monte Carlo models for high energy particle interactions. The resulting flux at the Earth (within the Sun's solid angle) is higher than the corresponding one from cosmic ray interactions with the Earth atmosphere. The smallness of the absolu

J. A. Aguilar-Saavedra, M. Masip

Numerical correlations between fermion masses and mixings could indicate the presence of a flavor symmetry at high energies. In general, the search for these correlations using low-energy data requires an estimate of leading-log radiative corrections. We present a complete analysis of the evolution between the electroweak and the grand unification scales of

G. Ingelman, M. Thunman

The flux of neutrinos and photons originating from cosmic ray interactions with the interstellar medium in the galaxy is calculated based on current models for high energy particle interactions. The contribution from a possible dark matter halo of the galaxy is considered. The photon flux gets a non-trivial attenuation due to interactions with the cosmic bac

Amitava Raychaudhuri, Probir Roy

This report summarises the work done during the Workshop on High Energy Physics Phenomenology 4 (S.N.Bose National Centre for Basic Sciences, Calcutta, India, Jan 2-14,1996) in Working Groups IV (Unification and Model Building) and V (Astroparticle Physics and Neutrinos).

S. K. Sahu et al

We measured the radiation damage on silica aerogel \v Cerenkov radiators originally developed for the $B$-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8~MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found

Yu. Ignat'ev, A. Popov

A solution of the linearized Einstein's equations for a spherically symmetric perturbation of the ultrarelativistic fluid in the homogeneous and isotropic universe is obtained. Conditions on the boundary of the perturbation are discussed. The examples of particle-like and wave-like solutions are given.

Takahiro Masuda, Hisao Suzuki

It is known that the radial equation of the massless fields with spin around Kerr black holes cannot be solved by special functions. Recently, the analytic solution was obtained by use of the expansion in terms of the special functions and various astrophysical application have been discussed. It was pointed out that the coefficients of the expansion by the

Ayse Humeyra Bilge

We show that the self-duality defined in [Trautman, Int.J.Theor.Phys.,{\bf 16},561 (1977)] is equivalent to strong self-duality defined in [Bilge, Dereli and Kocak, Lett.Math.Phys., {\bf 36}, 301-309, (1996)] and we obtain an upper bound on $\int (p_2)^{n}$, where $p_2$ is the second Pontrjagin class of an $SO(N)$ bundle over a $8n$ dimensional manifold.

T. Bergeman

A self-consistent mean-field theory for bosons for T>0 is used to reconcile predictions of collapse with recent observations of Bose-Einstein condensation of 7Li. Eigenfunctions of a (non-separable) Hamiltonian that includes the anisotropic external trap field and atom-atom interactions are obtained by an iteration process. A sum over the Bose distribution,

S. V. Kravchenko

In a recent Rapid Communication ``Observation of the $ν=1$ quantum Hall effect in a strongly localized two-dimensional system,'' Shahar, Tsui, and Cunningham reported a disorder --- magnetic field phase diagram for the integer quantum Hall effect that appeared to differ qualitatively from theoretical predictions as well as from experimental results o

L. L. Bonilla, M. Kindelan, M. Moscoso, A. Wacker

We review the statics and dynamics of electric-field domains on doped superlattices within a discrete drift model. A complete analysis of the construction and stability of stationary field profiles having two domains is carried out. As a consequence we determine the intervals of doping on which self-sustained current oscillations may appear under dc voltage

Jan von Delft, Dmitrii S. Golubev, Wolfgang Tichy, Andrei D. Zaikin

We investigate the breakdown of BCS superconductivity in {\em ultra}\/small metallic grains as a function of particle size (characterized by the mean spacing $d$ between discrete electronic eigenstates), and the parity ($P$ = even/odd) of the number of electrons on the island. Assuming equally spaced levels, we solve the parity-dependent BCS gap equation for

T. J. Newman, A. J. Bray

We present a systematic discretization scheme for the Kardar-Parisi-Zhang (KPZ) equation, which correctly captures the strong-coupling properties of the continuum model. In particular we show that the scheme contains no finite-time singularities in contrast to conventional schemes. The implications of these results to i) previous numerical integration of the

Andreas Engel

Feed-forward multilayer neural networks implementing random input-output mappings develop characteristic correlations between the activity of their hidden nodes which are important for the understanding of the storage and generalization performance of the network. It is shown how these correlations can be calculated from the joint probability distribution of

F. Dalfovo, L. Pitaevskii, S. Stringari

Through a suitable expansion of the Gross-Pitaevskii equation near the classical turning point, we obtain an explicit solution for the order parameter at the boundary of a trapped Bose gas interacting with repulsive forces. The kinetic energy of the system, in terms of the classical radius $R$ and of the harmonic oscillator length $a_{_{HO}}$, follows the la

A. Voigt, J. Richter

We examine the influence of an anisotropic interaction term of Dzyaloshinskii-Moriya (DM) type on the groundstate ordering of the J_1-J_2 spin-1/2-Heisenberg antiferromagnet on the square lattice. For the DM term we consider several symmetries corresponding to different crystal structures. For the pure J_1-J_2 model there are strong indications for a quantum

Ramin Golestanian, Mark Goulian, Mehran Kardar

We consider the interaction between two rods embedded in a fluctuating surface. The modification of fluctuations by the rods leads to an attractive long-range interaction between them. We consider fluctuations governed by either surface tension (films) or bending rigidity (membranes). In both cases the interaction falls off with the separation of the rods as

Yongmin Yu, Gerhard Müller, V. S. Viswanath

The dynamical properties at T=0 of the one-dimensional (1D) s=1/2 nearest-neighbor (nn) XXZ model with an additional isotropic next-nearest-neighbor (nnn) coupling are investigated by means of the recursion method in combination with techniques of continued-fraction analysis. The focus is on the dynamic structure factors S_{zz}(q,ω) and S_{DD}(q,ω), which de

Y. Alhassid, H. Attias

We compute the parametric correlation function of the conductance peaks in chaotic and weakly disordered quantum dots in the Coulomb blockade regime and demonstrate its universality upon an appropriate scaling of the parameter. For a symmetric dot we show that this correlation function is affected by breaking time-reversal symmetry but is independent of the

Kemal Oflazer, Okan Yilmaz

We present a constraint-based case frame lexicon architecture for bi-directional mapping between a syntactic case frame and a semantic frame. The lexicon uses a semantic sense as the basic unit and employs a multi-tiered constraint structure for the resolution of syntactic information into the appropriate senses and/or idiomatic usage. Valency changing trans

A. Frank, R. Lemus, R. Bijker, F. Perez-Bernal

We introduce the Anharmonic Oscillator Symmetry Model to describe vibrational excitations in molecular systems exhibiting high degree of symmetry. A systematic procedure is proposed to establish the relation between the algebraic and configuration space formulations, leading to new interactions in the algebraic model. This approach incorporates the full powe

O. I. Gorsky, Yu. P Kuchugurny

A behaviour of molecular cluster with Lennard-Jones potential of interactions as Hamiltonian system is studied by computer simulation (molecular dynamics method). It is shown that complex periodic oscillations of the cluster as a whole are possible. This is in accordance with KAM theorem.

A. B. Balantekin, J. M. Fetter, F. N. Loreti

We consider the effect on matter-enhanced neutrino flavor transformation of a randomly fluctuating, delta-correlated matter density. The fluctuations will produce a distribution of neutrino survival probabilities. We find the mean and variance of the distribution for the case of solar neutrinos, and discuss the possibility of placing a limit on solar density

Abraham Loeb

The Lyman-alpha absorption systems observed in the spectra of QSOs are likely to possess bulk peculiar velocities. The free electrons in these systems scatter the microwave background and distort its spectrum through the kinematic Sunyaev-Zel'dovich effect. I calculate the temperature fluctuations of the microwave sky due to variations in the number of L

R. A. Battye, E. P. S. Shellard

We discuss the potential cosmological role of gravitational wave astronomy as a probe of the very early universe. The next generation of detectors - now in production - may be able to observe a stochastic background of gravitational waves produced by violent processes during the earliest moments after the creation of the universe. Viable theoretical scenario

J. H. Huang, Q. S. Gu, H. J. Su, Z. H. Shang

We have observed an object having strong Balmer absorption lines and blue continuum. The inference about the nuclear stellar population drawn from the line ratios is basically coincident with that drawn from the continuum color, both indicating the dominant fraction of early A type population in the nucleus. This might be expected only if there has been a ve

Juergen Knoedlseder, Uwe Oberlack, Roland Diehl, Wan Chen

We report the negative results of our searches in COMPTEL data for 1.809 MeV gamma-ray line emission from four localized regions which contain nearby supernova remnants (SNRs). The upper flux limits (2 Sigma) are found to be in the range of 1.4*10e-5 to 2.4*10e-5 photons/s/cm/cm. These upper limits do not severely constrain the theoretical 26Al yields from i

J. G. Kirk, P. Duffy, Y. A. Gallant

The theory of diffusive acceleration of energetic particles at shock fronts assumes charged particles undergo spatial diffusion in a uniform magnetic field. If, however, the magnetic field is not uniform, but has a stochastic or braided structure, the transport of charged particles across the average direction of the field is more complicated. Assuming quasi

Paolo Padoan, Raul Jimenez, Bernard Jones

Using a new physical model for star formation (Padoan 1995) we have tested the possibility that globular clusters (GCs) are formed from primordial mass fluctuations, whose mass scale ($10^8$ - $10^9$ M$_{\odot}$) is selected out of a CDM spectrum by the mechanism of non-equilibrium formation of $H_2$. We show that such clouds are able to convert about 0.003

J. Knoedlseder, K. Bennett, H. Bloemen, R. Diehl

Significant 1.8 MeV emission from the Carina region has been detected by COMPTEL. The emission is concentrated within 6 degrees or less near the Carina nebula NGC 3372, one of the brightest HII regions known in our Galaxy. This region contains a wealth of extreme young open clusters whose massive stars possibly contributed to an enrichment of 26Al in the ISM

J. Knoedlseder, N. Prantzos, K. Bennett, H. Bloemen

COMPTEL imaging analysis revealed a patchy, asymmetric distribution of diffuse 1.8 MeV emission along the Galactic plane, which is attributed to the decay of radioactive 26Al in the ISM. If massive stars were the major source of Galactic 26Al, the 1.8 MeV emission should be asymmetric and trace the spiral arms of the Galaxy, presumed site of massive star for

Hajime Susa, Hideya Uehara, Ryoichi Nishi

We investigated the thermal evolution of non-spherical primordial gas clouds of mass $ M=10^6M_\odot $. We studied two cases: 1) prolate and oblate clouds without angular momentum, 2) initially spherical, oblate and prolate clouds with angular momentum. In the spherical case, the magnitude of the angular momentum is the key quantity which determines the frag

Sinan Sertoz

Algebraic curve branches can be classified according to their multiplicity sequences. Arf's solution to this problem using Arf closures and possible implementations of Henselization are discussed.

Peter Sollich

In supervised learning, the redundancy contained in random examples can be avoided by learning from queries. Using statistical mechanics, we study learning from minimum entropy queries in a large tree-committee machine. The generalization error decreases exponentially with the number of training examples, providing a significant improvement over the algebrai

B. Norum, R. Rossmanith

This paper presents a first overview on how to obtain and maintain polarized beams in a muon-collider

Amit Ghosh

Here we discuss the two dimensional quantum electrodynamics in curved space-time, especially in the background of some black holes. We first show the existence of some new quantum mechanical solution which has interesting properties. Then for some special black holes we discuss the fermion-black hole scattering problem. The issue of confinement is intimately

R. Dijkgraaf, E. Verlinde, H. Verlinde

We give a unified description of all BPS states of M-theory compactified on $T^5$ in terms of the five-brane. We compute the mass spectrum and degeneracies and find that the $SO(5,5,Z)$ U-duality symmetry naturally arises as a T-duality by assuming that the world-volume theory of the five-brane itself is described by a string theory. We also consider the com

Mikhail S. Volkov

A detailed quantitative analysis of the transition process mediated by a sphaleron type non-Abelian gauge field configuration in a static Einstein universe is carried out. By examining spectra of the fluctuation operators and applying the zeta function regularization scheme, a closed analytical expression for the transition rate at the one-loop level is deri

D. Fargion

A sequence of prompt and delayed radio signals at tens of kilohertz should reach the Earth (or Jupiter) due to graviton--photon conversion in interstellar as well as local planetary magnetic fields. These radio fluxes may be a detectable probe of a huge gravitational burst expected from Supernovae explosions. The earliest prompt radio signal, coinciding with

Cheuk-Yin Wong, Chun Wa Wong

The cross section between a $c \bar c$ pair and a nucleon is small and sensitive to the $c - \bar c$ separation if the pair is in a color-singlet state, but very large and insensitive to the separation if it is in a color-octet state. We use this property in an absorption model involving both color components to deduce the color structure of $c \bar c$ pairs

Fabio Gavarini

Let $ G^τ$ be a connected simply connected semisimple algebraic group, endowed with generalized Sklyanin-Drinfeld structure of Poisson group; let $ H^τ$ be its dual Poisson group. By means of Drinfeld's double construction and dualization via formal Hopf algebras, we construct new quantum groups $ U_{q,ϕ}^M ({\frak h}) $ --- dual of $ U_{q,ϕ}^{M'} ({

Shaun Cole

Tormen and Bertschinger have presented an algorithm which allows the dynamic range of N-body simulations to be extended by adding long-wavelength power to an evolved N-body simulation. This procedure is of considerable interest as it will enable mock galaxy catalogues to be constructed with volumes as large as those of the next generation of galaxy redshift

Yűji Ohta

We discuss the N=2 SU(2) Yang-Mills theory coupled with a massive matter in the weak coupling. In particular, we obtain the instanton expansion of its prepotential. Instanton contributions in the mass-less limit are completely reproduced. We study also the double scaling limit of this massive theory and find that the prepotential with instanton corrections i

Ralf Hempfling

In the standard model (SM) the condition that the Higgs mass parameter vanishes is stable under radiative corrections and yields a theory that can be renormalized using dimensional regularization. Thus, this model allows to predict the Higgs boson mass. However, it is phenomenologically ruled out in its minimal version. Here, we present a phenomenologically

Andrew Matacz

The stochastic inflation program is a framework for understanding the dynamics of a quantum scalar field driving an inflationary phase. Though widely used and accepted, there have over recent years been serious criticisms of this theory. In this paper I will present a new theory of stochastic inflation which avoids the problems of the conventional approach.

I. I. Mazin, R. E. Cohen

We discuss several aspects of the dielectric response theory application to the density functional theory. This field has been an unceasing source of confusion during several decades. The most frequent reasons for this confusion are (a) uncritical tranfer of the results, especially regarding so-called local field corrections, obtained in many-body perturbati

N. P. Landsman

The space P of pure states of any physical system, classical or quantum, is identified as a Poisson space with a transition probability. The latter is a function p: PxP -> [0,1]; in addition, a Poisson bracket is defined for functions on P. These two structures are connected through unitarity. Classical and quantum mechanics are each characterized by a simpl

Razvan Gelca

The paper contains the construction of a topological quantum field theory in which gluings along surfaces with boundary are allowed. The construction is made by using quantum deformations of sl(2,C). In the construction there appears a sign obstruction to some of the Moore-Seiberg equations. This problem is solved by means of the Klein four group.

L. Wilets, M. A. Alberg, J. Carlson, W. Koepf

The measurement and analysis of electron scattering from He-3 and He-4 by Sick and collaborators reported 20 years ago remains a matter of current interest. By unfolding the measured free-proton charge distribution, they deduced a depression in the central point nucleon density, which is not found in few-body calculations based on realistic potentials. We fi

V. V. Burov, A. V. Molochkov

We analyze nuclear effects in the deep inelastic scattering on deuteron in the framework of the covariant approach. It is shown that this approach gives us the way to investigate the role of relativistic effects in the deep inelastic scattering (DIS) on deuteron, such as the relativistic kinematics and the off-mass-shell behavior of the Compton amplitude of

Tong Zhou, Leo Kadanoff

A system of three particles undergoing inelastic collisions in arbitrary spatial dimensions is studied with the aim of establishing the domain of ``inelastic collapse&#39;&#39;---an infinite number of collisions which take place in a finite time. Analytic and simulation results show that for a sufficiently small restitution coefficient, $0\leq r<7-4\sqrt{3}\

Dennis P. Clougherty, John P. Gorman

The vibrational spectrum of C$_{60}$ is compared to the spectrum of a classical isotropic elastic spherical shell. We show correlations between the low frequency modes of C$_{60}$ and those of the spherical shell. We find the spherical model gives the approximate frequency ordering for the low frequency modes. We estimate a Poisson ratio of $σ\approx 0.30$ a

Junjiro Noguchi

The algebraic degeneracy of holomorphic curves in a semi-Abelian variety omitting a divisor is proved (Lang&#39;s conjecture generalized to semi-Abelian varieties) by making use of the {\it jet-projection method} and the logarithmic Wronskian jet differential after Siu-Yeung. We also prove a structure theorem for the locus which contains all possible image o

Junjiro Noguchi

S. Lang conjectured in 1974 that a hyperbolic algebraic variety defined over a number field has only finitely many rational points, and its analogue over function fields. We discuss the Nevanlinna-Cartan theory over function fields of arbitrary dimension and apply it for Diophantine property of hyperbolic projective hypersurfaces (homogeneous Diophantine equ

Jacek Pawelczyk

A two-dimensional string model with dynamical cancellation of folds is considered. The action of the model contains the self-intersection number which is defined for surfaces immersed into 4D targets. The two additional variables are not dynamical and live on a compact manifold. In this sense the model is a compactification of a 4D theory. The cancellation f

F. Cooper, Y. Kluger, E. Mottola

We give evidence that the production of DCC&#39;s during a non-equilibrium phase transition can lead to an anomalous transverse distribution of secondary pions when compared to a more conventional boost invariant hydrodynamic flow in local thermal equilibrium. Our results pertain to the linear $σ$ model,treated in leading order in large-$N$, in a boost invar

John F. Donoghue, Eugene Golowich, Alexey A. Petrov, João M. Soares

By using very general and well established features of soft strong interactions we show, contrary to conventional expectations, that (i) soft final state interactions (FSI) do not disappear for large $m_B$, (ii) inelastic rescattering is expected to be the main source of soft FSI phases, and (iii) flavor off-diagonal FSI are suppressed by a power of $m_B$, b

Erwin Mirkes, Dieter Zeppenfeld

Two-jet cross sections in deep inelastic scattering at HERA are calculated in next-to-leading order. The importance of higher order corrections and recombination scheme dependencies is studied for various jetalgorithms. Some implications for the determination of $α_s(μ_R^2)$, the determination of the gluon density and the associated forward jet production in

D. Jido, N. Kodama, M. Oka

The negative-parity baryons are studied by a novel approach in the QCD sum rule. It is found that the parity of the ground-state nucleon is determined by the sign of the quark condensate. We predict the mass of negative-parity nucleon.

G. Colangelo, M. Finkemeier, R. Urech

In a small window of phase space, chiral perturbation theory can be used to make standard model predictions for tau decays into two and three pions. For $τ\to 2πν_τ$, we give the analytical result for the relevant form factor $F_V$ up to two loops, then calculate the differential spectrum and compare with available data. For $τ\to 3 πν_τ$, we have calculated

Srinath Cheluvaraja, H. S. Sharathchandra

It is shown that $SO(3)$ lattice gauge theory on finite size lattices has metastable states related to the ground states of both the bulk transition and the finite temperature transition. The Polyakov line variable in the adjoint representation of $SU(2)$ is used to trace the origin of these metastable states. It is also argued that a second order finite tem

H. Meyer-Ortmanns, T. Reisz

Linked cluster expansions are generalized from an infinite to a finite volume. They are performed to 20th order in the expansion parameter to approach the critical region from the symmetric phase. A new criterion is proposed to distinguish 1st from 2nd order transitions within a finite size scaling analysis. The criterion applies also to other methods for in

F. I. Mikhail, M. I. Wanas, G. G. L. Nashed

The field equations of the new general relativity constructed by Hayashi and Shirafuji (1979), have been applied to two different geometric structures, given by Robertson (1932), in the domain of cosmology. In the first application a family of models, involving two of the parameters characterizing the field equations of the new general relativity, is obtaine

Razvan Gelca

The paper contains examples of Fredholm n-tuples of operators that are of index 0 but cannot be perturbed by compact operators to n-tuples with exact Koszul complex.

Razvan Gelca

The paper contains the proof, in dimension 2, of a conjecture of R. G. Douglas and V. Paulsen concerning the characterization of the ideals of polynomials which are closed in the relative topology induced by the Hardy space of the polydisk.

Razvan Gelca

The paper gives a negative answer to the question whether one can perturb a Fredholm pair of index 0 by compact operators to a pair with exact Koszul complex.

John M. Golden, Bertrand I. Halperin

We extend earlier results on the relation between the dimensionless tunneling channel conductance $g$ and the fractional Coulomb blockade peak splitting $f$ for two electrostatically equivalent dots connected by an arbitrary number $N_{\text{ch}}$ of tunneling channels with bandwidths $W$ much larger than the two-dot differential charging energy $U_{2}$. By

Paul M. Goldbart, Horacio E. Castillo, Annette Zippelius

As Charles Goodyear discovered in 1839, when he first vulcanised rubber, a macromolecular liquid is transformed into a solid when a sufficient density of permanent crosslinks is introduced at random. At this continuous equi- librium phase transition, the liquid state, in which all macromolecules are delocalised, is transformed into a solid state, in which a

Gianni Blatter, Mikhail Feigel&#39;man, Vadim Geshkenbein, Anatoli Larkin

In a type II superconductor the gap variation in the core of a vortex line induces a local charge modulation. Accounting for metallic screening, we determine the line charge of individual vortices and calculate the electric field distribution in the half space above a field penetrated superconductor. The resulting field is that of an atomic size dipole ${\bf

P. W. Brouwer, C. W. J. Beenakker

A diagrammatic method is presented for averaging over the circular ensemble of random-matrix theory. The method is applied to phase-coherent conduction through a chaotic cavity (a ``quantum dot&#39;&#39;) and through the interface between a normal metal and a superconductor.

J. A. Melsen, P. W. Brouwer, K. M. Frahm, C. W. J. Beenakker

Random-matrix theory is used to show that the proximity to a superconductor opens a gap in the excitation spectrum of an electron gas confined to a billiard with a chaotic classical dynamics. In contrast, a gapless spectrum is obtained for a non-chaotic rectangular billiard, and it is argued that this is generic for integrable systems.

Pinaki Majumdar, H. R. Krishnamurthy

We examine the effects of a van Hove singularity (vHs) in the density of states (DOS) of a two dimensional, $t-t&#39;-U$ Hubbard model within the local approximation. Within our approximation the non-interacting Fermi surface is always retained away from half-filling; and we find that the vHs in the DOS survives, and for hole doping is nearly &#34;pinned&#34

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

We give a statistical characterization of states with nonzero winding number in the Phase Turbulence (PT) regime of the one-dimensional Complex Ginzburg-Landau equation. We find that states with winding number larger than a critical one are unstable, in the sense that they decay to states with smaller winding number. The transition from Phase to Defect Turbu

D. A. Verner, E. M. Verner, G. J. Ferland

We list vacuum wavelengths, energy levels, statistical weights, transition probabilities and oscillator strengths for permitted resonance spectral lines of all ions of 18 astrophysically important elements (H through Si, S, Ar, Ca, Fe). Using a compilation of experimental energy levels, we derived accurate wavelengths for 5599 lines of 1828 ground-term multi

Rachel S. Somerville, Joel R. Primack, Richard Nolthenius

The velocity dispersion of galaxies on small scales ($r\sim1h^{-1}$ Mpc), $σ_{12}(r)$, can be estimated from the anisotropy of the galaxy-galaxy correlation function in redshift space. We apply this technique to ``mock-catalogs&#39;&#39; extracted from N-body simulations of several different variants of Cold Dark Matter dominated cosmological models to obtai

J. H. Huang, Q. S. Gu, H. J. Su, T. G. Hawarden

We use the ratio $L_{\rm FIR}/L_{\rm B}$ and the IRAS color index S$_{25}$/S$_{12}$ (both widely used as indices of relative star formation rates in galaxies) to analyse subsets (containing no known AGNs or merging/interacting galaxies) of: (a) the IRAS Bright Galaxy Sample, (b) galaxies from the optically complete RSA sample which have IRAS detections in al

C. Murali, M. D. Weinberg

We study the combined effects of relaxation, tidal heating and binary heating on globular cluster evolution, exploring the physical consequences of external effects and examining evolutionary trends in the Milky Way population. Our analysis demonstrates that heating on circular and low-eccentricity orbits can dominate cluster evolution. The results also pred

Q. -S. Gu, X. -H. Liao, J. -H. Huang, Q. -Y. Qu

New test-particle simulations have been performed to study the secular evolution of the gaseous distribution in NGC 4736. We find that the distribution of gas clouds can be understood in the frame of perturbation induced by a nuclear oval potential, in addition to a spiral-like potential. Our experiments show that both inner and outer rings are stable struct

Elaine M. Sadler, R. Michael Rich, D. M. Terndrup

This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade&#39;s Window, including most of the stars with proper motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first paper, we measured line--strength indices of Fe, Mg, CN and H$β$ and calibrated them on the system of Faber et al. [ApJS, 57, 7

Pilar Ruiz-Lapuente

Type Ia supernovae (SNe Ia), produced by the thermonuclear explosion of white dwarf (WD) stars, are used here to derive extragalactic distances and an estimate of the Hubble constant from their emission signatures at late phases ({\it Nebular SNe Ia Method}, NSM). The method, first developed in Ruiz--Lapuente \& Lucy (1992), makes use here of an improved mod

R. Sivron, D. Caditz, S. Tsuruta

In this paper we show that perturbations of the accretion flow within the central engines of active galctic nuclei (AGN) are likely to form shock waves in the accreting plasma. Such shocks, which may be either collisional or collisionless, can contribute to the observed high energy temporal and spectral variability. Our Rationale is the following: Observatio

Jason X. Prochaska, Arthur M. Wolfe

We present high resolution ($\approx 8$ \kms) spectra of the QSO Q0201+365 obtained with HIRES, the echelle spectrograph on the 10m W.M. Keck Telescope. Although we identify over $80\%$ of the absorption features and analyze several of the more complex metal-line systems, we focus our analysis on the damped \Lya system at $z=2.462$. Ionization simulations su

Bas Edixhoven

We give another proof of Imin Chen&#39;s result that the jacobian of the modular curve X(p)_{non-split}, for p a prime number, is isogeneous to the new part of the jacobian of X_0(p^2), using only the representation theory of the group GL_2(Z/pZ). In fact, we prove a generalization of Chen&#39;s result for objects with an action by GL_2(Z/pZ) in any pseudo-a

C. D. Fosco

The probability amplitude for tunneling between the Dirac vacua corresponding to different signs of a parity breaking fermionic mass $M$ in $2+1$ dimensions is studied, making contact with the continuum overlap formulation for chiral determinants. It is shown that the transition probability in the limit when $M \to \infty$ corresponds, via the overlap formal

Jerrold Franklin

Model independent sum rules are applied to recent measurements of heavy c-baryon and d-baryon masses. The sum rules are generally satisfied to the same degree as for the light (u,d,s) baryons.

Christoph Durr, Miklos Santha

Linear quantum cellular automata were introduced recently as one of the models of quantum computing. A basic postulate of quantum mechanics imposes a strong constraint on any quantum machine: it has to be unitary, that is its time evolution operator has to be a unitary transformation. In this paper we give an efficient algorithm to decide if a linear quantum

C. O&#39;Donovan, J. P. Carbotte

For a two layer system in a weak coupling BCS formalism any interlayer interaction, regardless of its sign, enhances the critical temperature. The sign has an effect upon the relative phase of the order parameter in each of the two planes but not upon its magnitude. When one of the planes has a dispersion consistent with CuO chains and no intrinsic pairing i

P. Q. Hung

A composite model of fermions is proposed to explain the &#34;anomaly&#34; in $Z \rightarrow b {\bar b}$ and, to a lesser extent, in $Z \rightarrow c {\bar c}$. It contains a {\em nonsequential} fourth family whose mass of one member (the charge -1/3 quark) is constrained to be between 47 GeV and 49 GeV. The charge +2/3 quark is constrained to lie between 67

G. E. Volovik

The spectrum of the fermion zero modes in the vicinity of the vortex with fractional winding number is discussed. This is inspired by the observation of the 1/2 vortex in high-temperature superconductors (Kirtley, et al, Phys. Rev. Lett. 76 (1996) 1336). The fractional value of the winding number leads to the fractional value of the invariant, which describe

D. van der Marel, J. Schützmann, H. S. Somal, J. W. van der Eb

Using infrared spectroscopy at grazing angle of incidence we study the electrodynamical properties of high temperature superconductors. We review some of our experiments where transverse polarized light is absorbed by longitudinal optical modes with their mode of oscillation perpendicular to the plane. This is particularly useful for the study of the plasmon

V. Bernard, N. Kaiser, Ulf-G. Meißner

We consider the chiral expansion of the threshold amplitude for the reaction $γp \to π^0 π^0 p$ to order ${\cal O}(M_π^2)$. We substantiate a claim that this photoproduction channel is significantly enhanced close to threshold due to pion loops. A precise measurement of the corresponding cross sections is called for which allows to test chiral perturbation t

K. Arai, Y. Ogawa, Y. Suzuki, K. Varga

The structure of the mirror nuclei $^9$Be and $^9$B is studied in a microscopic $α+ α+ n$ and $α+ α+ p$ three-cluster model using a fully antisymmetrized 9-nucleon wave function. The two-nucleon interaction includes central and spin-orbit components and the Coulomb potential. The ground state of $^9$Be is obtained accurately with the stochastic variational m

J. M. Rickman, Jorge Vinals

A phenomenological model of the evolution of an ensemble of interacting dislocations in an isotropic elastic medium is formulated. The line-defect microstructure is described in terms of a spatially coarse-grained order parameter, the dislocation density tensor. The tensor field satisfies a conservation law that derives from the conservation of Burgers vecto

Alexander Laufer

A finite expansion of the exponential map for a $N\times N$ matrix is presented. The method uses the Cayley-Hamilton theorem for writing the higher matrix powers in terms of the first N-1 ones. The resulting sums over the corresponding coefficients are rational functions of the eigenvalues of the matrix.

Achim Kempf

Quantum mechanics ordinarily describes particles as being pointlike, in the sense that the uncertainty $Δx$ can, in principle, be made arbitrarily small. It has been shown that suitable correction terms to the canonical commutation relations induce a finite lower bound to spatial localisation. Here, we perturbatively calculate the corrections to the energy l

C. Gomez, R. Hernandez, E. Lopez

In these notes evidence is presented for intepreting the moduli space of the integrable model associated to $N\!=\!2$ gauge theories with $N\!=\!4$ matter content, in terms of Calabi-Yau manifolds. We restrict to the case of gauge group $SU(2)$, which is compared with the moduli space of the Calabi-Yau manifold $WP_{11226}^{12}$ appearing in the rank three d