August 1994 arXiv papers — page 6

S. F. Hassan

It is shown that the O(d,d;R) deformations of the superstring vacua and the O(d,d+16;R) deformations of the heterotic string vacua preserve extended worldsheet supersymmetry and, hence, generate superconformal deformations. The transformations of the complex structures are given explicitly and the action of the discrete duality subgroup is discussed. The res

A. Shariati, A. Aghamohammadi

Using the multi-parametric deformation of the algebra of functions on $ \GL{n+1} $ and the universal enveloping algebra $ \U{\igl{n+1}} $, we construct the multi-parametric quantum groups $ \IGLq{n} $ and $ \Uq{\igl{n}} $.

P. S. Howe, M. I. Leeming

Harmonic superspaces for spacetimes of dimension $d\leq 3$ are constructed. Some applications are given.

A. K. Rebhan

It is shown that a perturbative treatment of nonabelian Debye screening at high temperature suffers from infrared problems already at the next-to-leading order, which is given by ring-resummed one-loop diagrams. Superficial infrared power counting would let one expect a sensitivity to the magnetic mass scale only at higher orders, but the form of Debye scree

Anton K. Rebhan

Debye screening of static chromoelectric fields at high temperature is investigated at next-to-leading order through one-loop resummed perturbation theory. At this order the gluon propagator appears to give rise to strong deviations from a Yukawa form of screening. Generally, an oscillatory behavior is found which asymptotically becomes repulsive, but in a g

Shin-ichi Sasa, Tsuyoshi Chawanya

Population dynamics in random ecological networks are investigated by analyzing a simple deterministic equation. It is found that a sequence of abrupt changes of populations punctuating quiescent states characterize the long time behavior. An asymptotic analysis is developed by introducing a log-scaled time, and it is shown that such a dynamical process beha

T. S. Kosmas, J. D. Vergados

$μ-e$ conversion is the experimentally most interesting lepton flavor violating process. From a theoretical point of view it is an interesting interplay of particle and nuclear physics. The effective transition operator, depending on the gauge model, is in general described in terms of a combination of four terms of transition operators (isoscalar and isovec

Paul Bankston

By a {\bf generalized arc\/} we mean a continuum with exactly two non-separating points; an {\bf arc} is a metrizable generalized arc. It is well known that any two arcs are homeomorphic (to the real closed unit interval); we show that any two generalized arcs are co-elementarily equivalent, and that co-elementary images of generalized arcs are generalized a

Swapna Mahapatra, Sudipta Mukherji

We investigate the cosmological solutions in closed bosonic string theory in the presence of non zero tachyon condensate. We specifically obtain time dependent solutions which describe an anisotropic universe. We also discuss the nature of such time dependent solutions when small tachyon fluctuations around the condensate are taken into account.

Gerald Dunne

We study the $SU(N)$ self-dual Chern-Simons-Higgs systems with adjoint matter coupling, and show that the sixth order self-dual potential has $p(N)$ gauge inequivalent degenerate minima, where $p(N)$ is the number of partitions of $N$. We compute the masses of the gauge and scalar excitations in these different vacua, revealing an intricate mass structure wh

Xerxes Tata

After a lightning review of current bounds on the masses of supersymmetric particles, we describe strategies that may be helpful for extracting signals from the production of squarks, gluinos or top squarks, and from associated chargino-neutralino production at the Tevatron. We then briefly review SUSY signals at hadron and $e^+e^-$ supercolliders. We discus

Zygmunt Lalak, Rudolf Poppe

We consider curved space quantum corrections to the equations of motion of the inflaton field in the early Universe. Using the stochastic formalism in phase space, we demonstrate that the quantum corrected evolution of the inflaton can differ dramatically from its classical evolution when the mass scales in the potential become large, which is naturally the

Su Houng Lee, Chungsik Song, Hiroyuki Yabu

The vector and axial vector current mixing phenomena at low temperature pion gas by Dey, Eletsky and Ioffe, leads to the low temperature correction of the photon-vector meson coupling ($g_ρ$) at order $ε=T^2/6f_π^2$ and the $ρ$ meson mass at order $ε^2$. We show how this {\it low temperature theorems} involving the photon and vector mesons are satisfied in t

H. Baer, C. H. Chen, R. Munroe, F. Paige

We examine the phenomenology of minimal supergravity models, assuming only that the low energy theory has the minimal particle content, that electroweak symmetry is radiatively broken, and that R-parity is essentially conserved. After delineating regions of supergravity parameter space currently excluded by direct particle searches at LEP and the Tevatron, w

A. V. Leonidov, G. M. Zinovjev

We obtain the constraints on the ruling parameters of the dense hadronic gas model at the critical temperature and propose the quasiuniversal ratios of the thermodynamic quantities. The possible appearence of thermodynamical instability in such a model is discussed.

M. A. Braun

The equation for two reggeized gluons in the vacuum channel is generalized to take into account the running QCD coupling constant on the basis of the bootstrap condition for gluon reggeization. Both the gluon trajectory as a function of momentum and the interaction as a function of distance grow like $\log\log$ in the ultraviolet. The resulting equation depe

Robert H. Gowdy

The generalized projection-tensor geometry introduced in an earlier paper is extended. A compact notation for families of projected objects is introduced and used to summarize the results of the previous paper and obtain fully projected decompositions of Lie derivatives of the projection tensor field, the metric and the projected parts of the metric. These r

Timothy J. Foxon

We investigate the Ponzano-Regge and Turaev-Viro topological field theories using spin networks and their $q$-deformed analogues. I propose a new description of the state space for the Turaev-Viro theory in terms of skein space, to which $q$-spin networks belong, and give a similar description of the Ponzano-Regge state space using spin networks. I give a de

Peter Huebner

For a class of scalar fields including the massless Klein-Gordon field the general relativistic hyperboloidal initial value problems are equivalent in a certain sense. By using this equivalence and conformal techniques it is proven that the hyperboloidal initial value problem for those scalar fields has an unique solution which is weakly asymptotically flat.

Colin Denniston, Chao Tang

We study the low temperature dynamics of a single flux line in a bulk type-II superconductor, driven by a surface current, both near and above the onset of an instability which sets in at a critical driving. We found that above the critical driving, the velocity profile of the flux line develops a discontinuity.

M. Alouani, J. W. Wilkins, R. C. Albers, J. M. Wills

This is a reply to J. T. Gammel's Comment (9404047) on Tuning of the CDW in MX Chains. We show that while the harmonic elastic energy can fit a small region around zero dimerization, it is insufficient to treat the large amplitude CDW of the MX systems which was the main physics of our Letter (Phys. Rev. Lett. {\bf 71}, 1415 (1993)). We also stress that

K. Ziegler

A two-dimensional lattice model for non-interacting fermions in a magnetic field with half a flux quantum per plaquette and $N$ levels per site is considered. This is a model which exhibits the Integer Quantum Hall Effect (IQHE) in the presence of disorder. It presents an alternative to the continuous picture for the IQHE with Landau levels. The large $N$ li

CJ Mellor, RH Eyles, JE Digby, AJ Kent

We have made the first phonon absorption measurements in the fractional quantum Hall régime. Experiments have been conducted on two samples which have similar electron densities but greatly differing mobilities. The energy gaps as measured by activation studies of the longitudinal resistance differ by a factor of two. Phonon absorption measurements give almo

I. L. Aleiner, H. U. Baranger, L. I. Glazman

We study the spectral density function of a two-dimensional electron liquid in a weak magnetic field, the filling factor $ν\gg 1$. A hydrodynamic model for low-energy excitations of the liquid is developed. It is found that even at $ν\gg 1$ the density of states exhibits a gap at low energies. Its width $2E_0$ depends on the strength of interaction only loga

Lee-Wen Chen, M. Cristina Marchetti

We have studied numerically the dynamics of a driven elastic interface in a random medium, focusing on the thermal rounding of the depinning transition and on the behavior in the $T=0$ pinned phase. Thermal effects are quantitatively more important than expected from simple dimensional estimates. For sufficient low temperature the creep velocity at a driving

Mustansir Barma, Deepak Dhar

We study the slow decay of the steady-state autocorrelation function $C(t)$ in a stochastic model of deposition and evaporation of trimers on a line with infinitely many conservation laws and sectors. Simulations show that $C(t)$ decays as different powers of $t$, or as $\exp (-t^{1/2})$, depending on the sector. We explain this diversity by relating the pro

Andrew Gould

Massive Compact Objects (Machos) are currently being discovered at substantially higher rates than would be expected from standard models of known stellar populations. To determine whether they are due to non-standard distri- butions of known populations or to a heretofore unknown (`dark') population, one must acquire more information about the individua

M. Beauchemin, E. F. Borra

We have conducted a galaxy survey based on low-resolution slitless spectra taken from the automated CFHT-Laval survey. We present redshift distributions for 522 galaxies distributed in 4 distinct regions of the sky. Redshifts are determined from the shifted positions of the 4000 A. stellar break using an automated break-finding algorithm. The redshifts so ob

Keith M. Ashman, Christina M. Bird, Steven E. Zepf

We discuss statistical techniques for detecting and quantifying bimodality in astronomical datasets. We concentrate on the KMM algorithm, which estimates the statistical significance of bimodality in such datasets and objectively partitions data into sub-populations. By simulating bimodal distributions with a range of properties we investigate the sensitivit

A. D. King, P. E. Newstead

We construct coarse moduli spaces for `Brill-Noether pairs'. Such a pair consists of a torsion-free sheaf $E$ over an algebraic curve $X$ and a vector subspace $Λ$ of its space of sections $H^0(E)$. The construction works for an arbitrary singular curve $X$ of pure dimension and for all values of the positive rational parameter $α$ occurring in the stabi

Christof Wetterich

For realistic values of the Higgs boson mass the high temperature electroweak phase transition cannot be described perturbatively. The symmetric phase is governed by a strongly interacting $SU(2)$ gauge theory. Typical masses of excitations and scales of condensates are set by the ``high temperature confinement scale'' $\approx 0.2\ T$. For a Higgs b

Alan R. White

Theoretical arguments for a new higher-color quark sector, based on Pomeron physics in QCD, are briefly described. The electroweak symmetry-breaking, Strong CP conservation, and electroweak scale CP violation, that is naturally produced by this sector is also outlined. A further consequence is that above the electroweak scale there will be a radical change i

Peter E. Haagensen, Yuri Kubyshin, José Ignacio Latorre, E. Moreno

We review the Exact Renormalization Group equations of Wegner and Houghton in an approximation which permits both numerical and analytical studies of nonperturbative renormalization flows. We obtain critical exponents numerically and with the local polynomial approximation (LPA), and discuss the advantages and shortcomings of these methods, and compare our r

Toshio Nakatsu

The partition function of $D_{N+1}$ topological string, the coupled system of topological gravity and $D_{N+1}$ topological minimal matter , is proposed in the framework of KP hierarchy. It is specified by the elements of $GL(\infty)$ which constitute the deformed family from the $A_{2N-1}$ topological string. Its dispersionless limit is investigated from th

Saharon Shelah

CWH, CWN stand for collectionwise Hausdorff and collectionwise normal respectively. We analyze the statement "there is a lambda-CWH not CWH first countable (Hausdorff topological) space". We prove the existence of such a space under various conditions, show its equivalence to: there is a lambda-CWN not CWN first countable space and give an equivalent

Mirna Džamonja, Kenneth Kunen

We investigate properties of the class of compact spaces on which every regular Borel measure is separable. This class will be referred to as MS. We discuss some closure properties of MS, and show that some simply defined compact spaces, such as compact ordered spaces or compact scattered spaces, are in MS. Most of the basic theory for regular measures is tr

Jamil Daboul, Michael Martin Nieto

For zero energy, $E=0$, we derive exact, quantum solutions for {\it all} power-law potentials, $V(r) = -γ/r^ν$, with $γ> 0$ and $-\infty < ν< \infty$. The solutions are, in general, Bessel functions of powers of $r$. For $ν> 2$ and $l \ge 1$ the solutions are normalizable; they correspond to states which are bound by the angular-momentum barrier. Surprisingl

Jamil Daboul, Michael Martin Nieto

For zero energy, $E=0$, we derive exact, classical solutions for {\em all} power-law potentials, $V(r)=-γ/r^ν$, with $γ>0$ and $-\infty <ν<\infty$. When the angular momentum is non-zero, these solutions lead to the orbits $\r(t)= [\cos μ(þ(t)-þ_0(t))]^{1/μ}$, for all $μ\equiv ν/2-1 \ne 0$. When $ν>2$, the orbits are bound and go through the origin. This lead

Shahn Majid, M. J. Rodriguez-Plaza

The Faddeev-Reshetikhin-Takhtajan method to construct matrix bialgebras from non-singular solutions of the quantum Yang-Baxter equation is extended to the anyonic or $\Z_n$-graded case. The resulting anyonic quantum matrices are braided groups in which the braiding is given by a phase factor.

Jonathan M. Evans, Philip A. Tuckey

We describe how geometrical methods can be applied to a system with explicitly time-dependent second-class constraints so as to cast it in Hamiltonian form on its physical phase space. Examples of particular interest are systems which require time-dependent gauge fixing conditions in order to reduce them to their physical degrees of freedom. To illustrate ou

Ashoke Sen, Barton Zwiebach

We construct a Batalin-Vilkovisky (BV) algebra on moduli spaces of Riemann surfaces. This algebra is background independent in that it makes no reference to a state space of a conformal field theory. Conformal theories define a homomorphism of this algebra to the BV algebra of string functionals. The construction begins with a graded-commutative free associa

Daniel Z. Freedman

The Hamiltonians of $SU(2)$ and $SU(3)$ gauge theories in 3+1 dimensions can be expressed in terms of gauge invariant spatial geometric variables, i.e., metrics, connections and curvature tensors which are simple local functions of the non-Abelian electric field. The transformed Hamiltonians are local. New results from the same procedure applied to the $SU(2

T. G. O&#39;Neill

The A-dependence of the quasielastic A(e,e&#39;p) reaction has been studied at SLAC with H-2, C, Fe, and Au nuclei at momentum transfers Q^2 = 1, 3, 5, and 6.8 (GeV/c)^2. We extract the nuclear transparency T(A,Q^2), a measure of the average probability that the struck proton escapes from the nucleus A without interaction. Several calculations predict a sign

R. Kirschner

Deep-inelastic scattering at small x is a new field of QCD phenomenology which HERA experiments started to explore. The data show the feature expected by the perturbative Regge asymptotics. We describe the parton picture of structure function evolution both for increasing $Q^2$ and for decreasing $x$ and discuss the leading logarithmic approximation of QCD o

J. Levelt, P. J. Mulders

Semi-inclusive deep inelastic scattering of polarized leptons off hadrons enables one to measure the antisymmetric part of the hadron tensor. For unpolarized hadrons this piece is odd under time reversal. In deep inelastic scattering it shows up as a $\langle \sin ϕ\rangle$ asymmetry for the produced hadrons. This asymmetry can be expressed as the product of

Ulf-G. Meißner

I review recent progress made in the calculation of nucleon properties in the framework of heavy baryon CHPT. Topics include: Compton scattering, $πN$ scattering, the anatomy of a low-energy constant and the induced pseudoscalar form factor.

Kari Enqvist, A. I. Rez, V. V. Semikoz

We consider random primordial magnetic fields and discuss their dissipation, coherence length $L_0$, scaling behaviour and constraints implied by the primoridal nucleosynthesis. Such magnetic fields could excite the right-helicity states of Dirac neutrinos, with adverse consequences for nucleosynthesis. We present solutions to the spin kinetic equation of a

Per Elmfors, Randy Kobes

Previous calculations of the thermal beta-function in a hot Yang--Mills gas at the one--loop level have exposed problems with the gauge dependence and with the sign, which is opposite to what one would expect for asymptotic freedom. We show that inclusion of higher--loop effects through a static Braaten--Pisarski resummation is necessary to consistently obta

M. Carena, C. E. M. Wagner

We study the properties of the Higgs and supersymmetric particle spectrum associated with the infrared fixed point solution of the top quark mass in the MSSM. We concentrate on the possible detection of these particles, analysing the deviations from the Standard Model predictions for the leptonic and hadronic variables measured at LEP and for the decay rate

G. D. Gollin, W. P. Hogan

Using a technique which employs a pair of solid scintillator regenerators, the E773 collaboration has measured several CP violation parameters in K meson decay at Fermilab. We report new results for the phase of eta_+-, the K_L-K_S mass difference, the K_S lifetime, and the phase difference Arg(eta_00)-Arg(eta_+-) in K ->pi pi decay. In addition, we report a

Marco Cavaglia`

We explore a simple toy model of interacting universes to establish that a small baby universe could become large ($\gg$ Planck length) if a third quantization mechanism is taken into account.

James M. Gelb, Edmund Bertschinger

We examine high-resolution gravitational N-body simulations of the $Ω=1$ cold dark matter (CDM) model in order to determine whether there is any normalization of the initial density fluctuation spectrum that yields acceptable results for galaxy clustering and velocities. Dense dark matter halos in the evolved mass distribution are identified with luminous ga

James M. Gelb, Edmund Bertschinger

We use numerical simulations of critically-closed cold dark matter (CDM) models to study the effects of numerical resolution on observable quantities. We study simulations with up to $256^3$ particles using the particle-mesh (PM) method and with up to $144^3$ particles using the adaptive particle-particle --particle-mesh (P$^3$M) method. Comparisons of galax

L. Ciotti

In this paper the concept of tomography of a collisionless stellar system of general shape is introduced, and a generalization of the Projected Virial Theorem is obtained. Applying the tomographic procedure we then derive a new family of virial equations which coincides with the already known ones for spherically symmetric systems. This result is obtained wi

Ron Donagi, Eyal Markman

In this work we construct an analytically completely integrable Hamiltonian system which is canonically associated to any family of Calabi-Yau threefolds. The base of this system is a moduli space of gauged Calabi-Yaus in the family, and the fibers are Deligne cohomology groups (or intermediate Jacobians) of the threefolds. This system has several interestin

Lawrence Ein, Oliver Küchle, Robert Lazarsfeld

Let $L$ be a nef line bundle on a smooth complex projective variety $X$ of dimension $n$. Demailly has introduced a very interesting invariant --- the Seshadri constant $ε(L,x)$ --- which in effect measures how positive $L$ is locally near a given point $x \in X$. For instance, Seshadri&#39;s criterion for ampleness may be phrased as stating that $L$ is ampl

L. Chandar, E. Ercolessi

The exact quantization of two models, the massive vector meson model and the Higgs model in the London limit, both describing massive photons, is presented. Even though naive arguments (based on gauge-fixing) may indicate the equivalence of these models, it is shown here that this is not true in general when we consider these theories on manifolds with bound

A. Bianconi, S. Jeschonnek, N. N. Nikolaev, B. G. Zakharov

The radius of interaction between the struck proton and spectator nucleons is close to the radius of short-distance two-nucleon correlations in nuclear matter, which makes final state interaction(FSI) an important background to production of protons with large missing momentum. We present a simple classification of the dominant FSI effects in $^4He(e,e&#39;p

Kai Hencken, Dirk Trautmann, Gerhard Baur

We study higher-order effects in the electromagnetic production of electron-positron pairs in relativistic heavy ion collisions. Treating the field of the heavy ions as an external field and neglecting the interaction among electrons and positrons, we show that the $N$-pair creation amplitude is the antisymmetrised product of $N$ one-pair creation amplitudes

Philip Boyland

In this paper techniques of twist map theory are applied to the annulus maps arising from dual billiards on a strictly convex closed curve G in the plane. It is shown that there do not exist invariant circles near G when there is a point on G where the radius of curvature vanishes or is discontinuous. In addition, when the radius of curvature is not $C^1$ th

J. C. Brunelli, A. Das

We show that the supersymmetric nonlinear Schrödinger equation can be written as a constrained super KP flow in a nonstandard representation of the Lax equation. We construct the conserved charges and show that this system reduces to the super mKdV equation with appropriate identifications. We construct various flows generated by the general nonstandard supe

N. Mohammedi

We examine the problem of constructing N=2 superconformal algebras out of N=1 non-semi-simple affine Lie algebras. These N=2 superconformal theories share the property that the super Virasoro central charge depends only on the dimension of the Lie algebra. We find, in particular, a construction having a central charge c=9. This provides a possible internal s

B. Rusakov, S. Yankielowicz

Using matrix model techniques we investigate the large N limit of generalized 2D Yang-Mills theory. The model has a very rich phase structure. It exhibits multi-critical behavior and reveals a third order phase transitions at all genera besides {\it torus}. This is to be contrasted with ordinary 2D Yang-Mills which, at large N, exhibits phase transition only

J. Barcelos-Neto, T. G. Dargam

We quantize the Einstein gravity in the formalism of weak gravitational fields by using the constrained Hamiltonian method. Special emphasis is given to the 2+1 spacetime dimensional case where a (topological) Chern-Simons term is added to the Lagrangian.

J. Barcelos-Neto, M. B. D. Silva

We study an extension of the symplectic formalism in order to quantize reducible systems. We show that a procedure like {\it ghost-of-ghost} of the BFV method can be applied in terms of Lagrange multipliers. We use the developed formalism to quantize the antisymmetric Abelian gauge fields.

G. Bimonte, G. Lozano

We consider an Electroweak string in the background of a uniform distribution of cold fermionic matter. As a consequence of the fermion number non-conservation in the Weinberg-Salam model, the string produces a long-range magnetic field.

Jean-Loup Gervais, Mikhail V. Saveliev

In the present note we give an explicit integration of some two--dimensionalised Lotka--Volterra type equations associated with simple Lie algebras, other than the familiar $A_n$ case, possessing a representation without branching. This allows us, in particular, to treat the first fundamental representations of $A_r$, $B_r$, $C_r$, and $G_2$ on the same foot

M. J. Herrero, E. Ruiz Morales

We study the electroweak interactions within the standard electroweak theory in the case where the Higgs particle is heavy, namely, $M_H \leq 1\;TeV$. By integrating out the Higgs boson to one loop we find the complete effective lagrangian, called electroweak chiral lagrangian, that is $SU(2)_L\times U(1)_Y$ invariant and contains the whole set of operators

F. Hautmann

Deep inelastic processes at small x are discussed in the framework of perturbative QCD at high energy. New results are presented on the quark anomalous dimensions beyond the leading logarithmic approximation, and their relevance to the structure functions being measured at HERA is pointed out. *Talk given at the XXIX Rencontres de Moriond, 19-26 March 1994,

Debajyoti Choudhury

We investigate the possibility of detecting a scalar leptoquark, coupling to the electron and the top, at a linear collider. For coupling strength equalling the weak coupling constant, the present mass bounds are of the order of 300 GeV. We demonstrate that at the NLC, one could detect such particles if their mass were less than a few TeV&#39;s.

N. Bilić, J. Cleymans, I. Dadić, D. Hislop

A calculation of thermal gluon decay shows that this process contributes significantly to strangeness production in a quark-gluon plasma. Our analysis does not support recent claims that this is the dominant process. In our calculations we take into account the resummed form of the transverse and longitudinal parts of the gluon propagator following the Braat

J. Engels, F. Karsch, K. Redlich

The lattice data for the energy density of $SU(2)$ gauge theory are calculated with \nop~derivatives of the coupling constants. These derivatives are obtained from two sources : i) a parametrization of the \nop~beta function in accord with the measured critical temperature and $Δβ-$values and ii) a \nop~calculation of the presssure. We then perform a detaile

Yi Wan, Philip Phillips, Qiming Li

We analyze here a model for single-electron charging in semiconductor quantum dots that includes the standard Anderson on-site repulsion (U) as well as the spin-exchange ($J_d$) that is inherently present among the electrons occupying the various quantum levels of the dot. We show explicitly that for ferromagnetic coupling ($J_d>0$), an s-d exchange for an S

H. S. Bokil, A. P. Young

We study the gauge glass model for the vortex glass transition in type--II superconductors, including screening of the interaction between vortices. {}From the size dependence of the domain wall energy we find that, in two--dimensions, the transition is at $T=0$ both with and without screening but the exponents are different in the two cases. In three-dimens

Kikuo Harigaya, Shuji Abe

Molecular exciton effects in the neutral and maximally doped C$_{60}$ (C$_{70}$) are considered using a tight binding model with long-range Coulomb interactions and bond disorder. By comparing calculated and observed optical spectra, we conclude that relevant Coulomb parameters for the doped cases are about half of those of the neutral systems. The broadenin

D. D. Dixon

Non-deterministic chaos is a new dynamical paradigm where a non-deterministic system is influenced by random perturbations to produce the appearance of complexity. The non-determinism is envisioned to occur only at a single point in phase space, where many trajectories intersect. In the presence of external random perturbations (noise), whenever the phase sp

A. Udalski, M. Szymanski, J. Kaluzny, M. Kubiak

The discoveries of 17 microlensing event candidates have been reported over the last year by three teams conducting unprecedented mass photometric searches in the direction of the Galactic bulge and the Magellanic Clouds. These include 10 events found by the OGLE collaboration, 5 by the MACHO team and 2 by the EROS team. All searches have the main goal to de

R. Brada, M. Milgrom

We describe a family of circular, and elliptical, finite disks with a disk potential that is a power of the radius. These are all flattened ellipsoids, obtained by squashing finite spheres with a power-law density distribution, and cutoff at some radius Ro. First we discuss circular disks whose circular rotation speed v is proportional to r^alpha, with any a

David JD Earn

Most numerical integration algorithms are not designed specifically for Hamiltonian systems and do not respect their characteristic properties, which include the preservation of phase space volume with time. This can lead to spurious damping or excitation. Methods that do preserve all the Hamiltonian properties, i.e., for which the time-forward map is symple

Luca Barbieri-Viale

Global intersection theories for smooth algebraic varieties via products in {\it appropriate}\, Poincaré duality theories are obtained. We assume given a (twisted) cohomology theory $H^*$ having a cup product structure and we let consider the ${\cal H}$-cohomology functor $X\leadsto H^{\#}_{Zar}(X,{\cal H}^*)$ where ${\cal H}^*$ is the Zariski sheaf associat

Lawrence M. Krauss, Peter J. Kernan

To elucidate the significance of the effect of systematic uncertainties in light element abundance estimates on cosmological bounds derivable from Big Bang Nucleosynthesis (BBN) we present tables giving bounds on $Ω_{baryon}$ and $N_ν$ as one changes the limits on primordial \he and $^7$Li. This allows us to derive new relations between these estimates and c

L. D. Faddeev

Lectures delivered at the International School of Physics &#34;Enrico Fermi&#34;, held in Villa Monastero, Varenna, Italy, 94.

The Spin Muon Collaboration

We measured the spin asymmetry in the scattering of 100 GeV longitudinally-polarized muons on transversely polarized protons. The asymmetry was found to be compatible with zero in the kinematic range $0.006<x<0.6$, $1<Q^2<30\,~\mbox{GeV}^2$. {}From this result we derive the upper limits for the virtual photon--proton asymmetry $A_2$, and for the spin structu

G. T. Horowitz, A. A. Tseytlin

We show that the leading order solution describing an extremal electrically charged black hole in string theory is, in fact, an exact solution to all orders in $\a&#39;$ when interpreted in a Kaluza-Klein fashion. This follows from the observation that it can be obtained via dimensional reduction from a five dimensional background which is proved to be an ex

A. L. Kataev

The procedure of the estimates of the higher-order perturbative QCD corrections to the physical quantities is generalized to the case when the quantities under consideration obey the renormalization group equationts with the corresponding anomalous dimension function. This procedure is used to estimate the $\alpha_s^3$-corrections to the singlet part of the

V. V. Kopenkin, A. K. Managadze, I. V. Rakobolskaya, T. M. Roganova

Alignment of main fluxes of energy in a target plane is found in families of cosmic ray particles detected in deep lead X-ray chambers. The fraction of events with alignment is unexpectedly large for families with high energy and large number of hadrons. This can be considered as evidence for the existence of coplanar scattering of secondary particles in int

Cheongho Han

Spin vectors of 60 galaxies in the ``Ursa Major Filament&#39;&#39; are obtained from CCD images and spectroscopic determinations of the directions of rotation. These data are used to remove the four-fold degeneracy introduced by the project ed images of galaxies, making possible the complete reconstruction of the galaxy spin vectors. Several possible organiz

S. V. Pokrovsky, V. L. Pokrovsky

A microscopic theory of the plasma resonance in layered metals is presented. It is shown that electron-impurity scattering can suppress the plasma resonance in the normal state and sharpen it in the superconducting state. Analytic properties of the conductivity for the electronic transport perpendicular to the layers are investigated. The dissipative part of

E. Keski-Vakkuri, G. Lifschytz, S. D. Mathur, M. E. Ortiz

The definition of matter states on spacelike hypersurfaces of a 1+1 dimensional black hole spacetime is considered. The effect of small quantum fluctuations of the mass of the black hole due to the quantum nature of the infalling matter is taken into account. It is then shown that the usual approximation of treating the gravitational field as a classical bac

A. Ceresole, R. D'Auria, S. Ferrara

We consider generic properties of the moduli space of vacua in $N=2$ supersymmetric Yang--Mills theory recently studied by Seiberg and Witten. We find, on general grounds, Picard--Fuchs type of differential equations expressing the existence of a flat holomorphic connection, which for one parameter (i.e. for gauge group $G=SU(2)$), are second order equations

L. Bonora, Q. P. Liu, C. S. Xiong

For any two arbitrary positive integers `$n$&#39; and `$m$&#39;, using the $m$--th KdV hierarchy and the $(n+m)$--th KdV hierarchy as building blocks, we are able to construct another integrable hierarchy (referred to as the $(n,m)$--th KdV hierarchy). The $W$--algebra associated to the \shs\, of the $(n,m)$--th KdV hierarchy (called $W(n,m)$ algebra) is iso

Chao-Hsi Chang, Yu-Qi Chen, Guo-Ping Han, Hong-Tao Jiang

Two of the approaches to the hadronic productions of the double heavy mesons $B_c$ and $B_c^*$ are investigated. Comparison in various aspects on the results obtained by the approaches is made and shown in figures and a table. Some trial understanding of the approaches themselves and the achieved results is presented. The results may be used as some referenc

A. Leike, R. Rueckl

We describe some characteristic properties of $B_c$ mesons and discuss the production and the prospects of detection in $e^+ e^-$, $γγ$, and $\bar pp/pp$ collisions. The production mechanisms considered here also play an important role in charmonium and bottomonium production.

Keh-Fei Liu

We report results on the nucleon structure obtained from the lattice quantum chromodynamics calculation. These include the axial, electromagnetic, $πNN$, and scalar form factors. The calculation is carried out at $β= 6$ on a $16^3 \times 24$ lattice with 24 quenched gauge configurations. The chiral limit results are extrapolated from several light quark case

Jennifer L. Pauls, Adrian L. Melott

To explain the rich structure of voids, clusters, sheets, and filaments apparent in the Universe, we present evidence for the convergence of the two classic approaches to gravitational clustering, the ``pancake&#39;&#39; and ``hierarchical&#39;&#39; pictures. We compare these two models by looking at agreement between individual structures -- the ``pancakes&

Yu. Makeenko

I investigate the Kazakov-Migdal (KM) model -- the Hermitean gauge-invariant matrix model on a D-dimensional lattice. I utilize an exact large-N solution of the KM model with a logarithmic potential to examine its critical behavior. I find critical lines associated with gamma_{string}=-1/2 and gamma_{string}=0 as well as a tri-critical point associated with

L. P. Kaptari, A. Yu. Umnikov, C. Ciofi degli Atti, S. Scopetta

A theoretical approach to the investigation of spin-dependent structure functions in deep inelastic scattering of polarized leptons off polarized nuclei, based on the effective meson-nucleon theory and operator product expansion method, is proposed and applied to deuteron and $^3He$. The explicit forms of the moments of the deuteron and $^3He$ spin-dependent

R. Amorim, J. Barcelos-Neto

We use the method due to Batalin, Fradkin and Tyutin (BFT) for the quantization of chiral boson theories. We consider the Floreanini-Jackiw (FJ) formulation as well as others with linear constraints.

Elizabeth Jurisich, James Lepowsky, R. L. Wilson

We study aspects of the theory of generalized Kac-Moody Lie algebras (or Borcherds algebras) and their standard modules. It is shown how such an algebra with no mutually orthogonal imaginary simple roots, including Borcherds&#39; Monster Lie algebra $\frak m$, can be naturally constructed from a certain Kac-Moody subalgebra and a module for it. We observe th

O. A. Soloviev

It is shown that the master equation of the affine-Virasoro construction on the unitary affine algebra naturally emerges in the fusion algebra of the nonunitary level $k$ WZNW model. Operators corresponding to solutions of the master equation are suitable for performing one-parametrical renormalizable perturbation around the given conformal nonunitary WZNW m