April 1993 arXiv papers — page 5

Pavel M. Bleher

We investigate the statistics of the number $N(R,S)$ of lattice points, $n\in \Z^2$, in a ``random'' annular domain $Π(R,w)=\,(R+w)A\,\setminus RA$, where $R,w >0$. Here $A$ is a fixed convex set with smooth boundary and $w$ is chosen so that the area of $Π(R,w)$ is $S$. The randomness comes from $R$ being taken as random ( with a smooth denisity ) i

Frank De Jonghe

In this short note we extend the results of Alfaro and Damgaard on the origin of antifields to theories with a gauge algebra that is open or reducible.

A. H. Chamseddine, J. Fr/''ohlich

We construct an $SO(10)$ grand unified theory in the formulation of non-com-\break mutative geometry. The geometry of space-time is that of a product of a continuos four dimensional manifold times a discrete set of points. The properties of the fermionic sector fix almost uniquely the Higgs structure. The simplest model corresponds to the case where the disc

Mihai Visinescu

A class of generalized Taub-NUT gravitational instantons is reported in five - dimensional Einstein gravity coupled to a non-linear sigma model. The geodesic dynamics of a spinless particle of unit mass on these static gravitational instantons is studied. This is accomplished by finding a generalized Runge-Lenz vector. Unlike the Kepler problem, or, the dyna

Miao Li

We study a revised version of Witten's 2d black hole, in which the matter and (b,c) ghosts are mixed. The level of the coset model is still 9/4. We show that this model is equivalent to that of Mukhi and Vafa, in which the level of the coset model is taken as 3, and the stress tensor is improved. We argue that the exact metric in such a model is just the

James M. Cline, Kimmo Kainulainen, Keith A. Olive

We derive strong contraints on the Yukawa couplings and the vacuum expectation value in the singlet majoron model, taking into account the possibility of a small gravitationally induced mass for the majoron. If the present baryon asymmetry was created earlier than at the electroweak phase transition, then to preserve it from the combined effects of lepton nu

Edmund J. Copeland, Edward W. Kolb, Andrew R. Liddle, James E. Lidsey

We show how observations of the density perturbation (scalar) spectrum and the gravitational wave (tensor) spectrum allow a reconstruction of the potential responsible for cosmological inflation. A complete functional reconstruction or a perturbative approximation about a single scale are possible; the suitability of each approach depends on the data availab

Eric Braaten

The spin asymmetry parameter $A_τ$ characterizing the angular distribution of the total hadron momentum in the decay of a polarized tau can be calculated rigorously using perturbative QCD and the operator product expansion. Perturbative QCD corrections to the free quark result $A_τ= 1/3$ can be expressed as a power series in $α_s(M_τ)$ and nonperturbative QC

P. T. Chrusciel, R. Wald

Existence of maximal hypersurfaces and of foliations by maximal hypersurfaces is proven in two classes of asymptotically flat spacetimes which possess a one parameter group of isometries whose orbits are timelike ``near infinity''. The first class consists of strongly causal asymptotically flat spacetimes which contain no ``black hole or white hole&#

K. Moon, H. Yi, C. L. Kane, S. M. Girvin

Resonant tunneling between fractional quantum Hall edge states is studied in the Luttinger liquid picture. For the Laughlin parent states, the resonance line shape is a universal function whose width scales to zero at zero temperature. Extensive quantum Monte Carlo simulations are presented for $ν= 1/3$ which confirm this picture and provide a parameter-free

Eric D. Williams

The free energy of the supersymmetric $t-J$ model is expressed in terms of finite temperature excitations above thermodynamic equilibrium. This reveals that the free energy has the form of noninteracting fermions with temperature dependant excitation spectra. We also discuss the ground state and zero temperature excitations.

N. Ito, G. A. Kohring

A comparison between single-cluster and single-spin algorithms is made for the Ising model in 2 and 3 dimensions. We compare the amount of computer time needed to achieve a given level of statistical accuracy, rather than the speed in terms of site updates per second or the dynamical critical exponents. Our main result is that the cluster algorithms become m

G. J. Chaitin

Lecture given Thursday 22 October 1992 at a Mathematics-Computer Science Colloquium at the University of New Mexico. The lecture was videotaped; this is an edited transcript.

K. Krisciunas, C. Aspin, T. R. Geballe, H. Akazawa

The F0 V star 9 Aur A exhibits an irregular variability of amplitude $\approx $0.1 magnitude at optical wavelengths. The variations are too slow for it to be a $δ$ Scuti-type star. There is no evidence for a close, interacting companion or ring of dust, either from infrared, ultraviolet, or speckle data. The photometric variability of 9 Aur A is similar to t

Xian Wu

Let $X$ be a hypersurface of degree $d$ in $\Bbb P^n$ and $F_X$ be the scheme of $\Bbb P^r$'s contained in $X$. If $X$ is generic, then $F_X$ will have the expected dimension (or empty) and its class in the Chow ring of $G(r+1,n+1)$ is given by the top Chern class of the vector bundle $S^dU^*$, where $U$ is the universal subbundle on the Grassmannian $G(

S. Bradlow, G. Daskalopoulos, R. Wentworth

We construct a finite dimensional Kaehler manifold with a holomorphic, symplectic circle action whose symplectic reduced spaces may be identified with the tau-vortex moduli spaces (or tau-stable pairs). The Morse theory of the circle action induces natural birational maps between the reduced spaces for different values of tau which in the case of rank two bu

Z. Bajnok

We consider the $C_2$ Toda theory in the reduced WZNW framework. Analysing the classical representation space of the symmetry algebra (which is the corresponding $C_2$ $W$ algebra) we determine its classical highest weight representations. We quantise the model promoting only the relevant quantities to operators. Using the quantised equation of motion we det

F. E. Close, G. J. Gounaris

We apply Heavy Quark Effective Theory to the production of $0^-$ and $1^-$ $Q\bar{q}$ states in $e^+ e^-$ annihilation. We show that HQET implies that the electric quadrupole amplitudes vanish and we propose tests for this theory. We also show how HQET can be applied to distinguish the $^3D_1$ and $^3S_1$ $Q\bar{Q}$ states.

Mihir Arjunwadkar, P. V. Panat, D. G. Kanhere

The question of spin-charge separation in two-dimensional lattices has been addressed by numerical simulations of the motion of one hole in a half-filled band. The calculations have been performed on finite clusters with Hubbard and t-J models. By comparing the time evolution of spin and charge polarisation currents in one and two dimensions, evidence in fav

S. M. Bilenky, C. Giunti, V. Wataghin

The discussion on the asymptotical behaviour of the form factors in the space-like and time-like regions have been corrected and clarified. Fig.3 has been replaced by an improved analysis of the data.

W. M. Alberico, P. Czerski, A. De Pace, V. R. Manfredi

We consider a slab of nuclear matter and investigate the collective excitations, which develop in the response function of the system. We introduce a finite-range realistic interaction among the nucleons, which reproduces the full G-matrix by a linear combination of gaussian potentials in the various spin-isospin channels. We then analyze the collective mode

C. J. Horowitz, H. O. Meyer, D. Griegel

Recent calculations of $s$-wave pion production have severely underestimated the accurately known $pp\rightarrow ppπ^0$\ total cross section near threshold. In these calculations, only the single-nucleon axial-charge operator is considered. We have calculated, in addition to the one-body term, the two-body contributions to this reaction that arise from the e

W. M. Alberico, M. B. Barbaro, A. De Pace, T. W. Donnelly

The impact of pionic correlations and meson--exchange currents in determining the (vector) response functions for electroweak quasielastic lepton scattering from nuclei is discussed. The approach taken builds on previous work where the Fermi gas model is used to maintain consistency in treating forces and currents (gauge invariance) and to provide a Lorentz

Alexander Sevrin, Kris Thielemans, Walter Troost

The effective actions for $d=2$, $N=3,4$ chiral supergravities with a linear and a non-linear gauge algebra are related to each other by a quantum reduction, the latter is obtained from the former by putting quantum currents equal to zero. This implies that the renormalisation factors for the quantum actions are identical.

K. -I. Kondo, K. Yoshida

Based on the real-time formalism, especially, on Thermo Field Dynamics, we derive the Schwinger-Dyson gap equation for the fermion propagator in QED and Four-Fermion model at finite-temperature and -density. We discuss some advantage of the real-time formalism in solving the self-consistent gap equation, in comparison with the ordinary imaginary-time formali

M. Bordag, S. Voropaev

We considered a charged quantum mechanical particle with spin ${1\over 2}$ and gyromagnetic ratio $g\ne 2$ in the field af a magnetic string. Whereas the interaction of the charge with the string is the well kown Aharonov-Bohm effect and the contribution of magnetic moment associated with the spin in the case $g=2$ is known to yield an additional scattering

Lisa Randall, Nuria Rius

We investigate the question of whether an additional light neutral scalar can explain the $l^+ l^- γγ$ events with high invariant mass photon pairs recently observed by the L3 collaboration. We parameterize the low energy effects of the unknown dynamics in terms of higher dimensional effective operators. We show that operators which allow for the scalar to b

I. I. Bigi, M. Shifman, N. G. Uraltsev, A. Vainshtein

We derive the lepton spectrum in semileptonic beauty decays from a nonperturbative treatment of QCD; it is based on an expansion in $1/m_Q$ with $m_Q$ being the heavy flavour quark mass. The leading corrections arising on the $1/m_Q$ level are completely expressed in terms of the difference in the mass of the heavy hadron and the quark. Nontrivial effects ap

Marco A. Diaz

Some aspects of the phenomenology of the top quark and the charged Higgs are studied, emphasizing relations due to radiative corrections. Production mechanisms at the SSC are mentioned, and decay modes are analyzed including radiative corrections to the charged Higgs mass and couplings. The constraints due to the decay b-> s γare discussed. Calculations are

Peter Cho

A set of Grand Unified Theories based upon the gauge groups $SU(5)_Ł\times SU(5)_\R$, $SO(10)_Ł\times SO(10)_\R$ and $SU(4)_\C \times SU(4)_Ł\times SU(4)_\R$ is explored. Several novel features distinguish these theories from the well-known $SU(5)$, $SO(10)$ and $SU(4)_\C \times SU(2)_Ł\times SU(2)_\R$ models which they generalize. Firstly, Standard Model qu

Jan Ambjorn, Poul Olesen

We review how external magnetic fields act as perfect probes of the non-abelian nature of the electroweak theory.

F. J. Botella, S. Noguera, J. Portolés

We analyze the decay modes of charmed mesons into two--pseudoscalars in a weak--gauged U(4)_L x U(4)_R chiral lagrangian model. The calculation is free of unknown parameters and only requires as inputs the masses of pseudoscalars and the decay constant of the pion. The general pattern of the results at leading order compares reasonably well with the experime

Chung-I Kuo, L. H. Ford

We discuss the limits of validity of the semiclassical theory of gravity in which a classical metric is coupled to the expectation value of the stress tensor. It is argued that this theory is a good approximation only when the fluctuations in the stress tensor are small. We calculate a dimensionless measure of these fluctuations for a scalar field on a flat

Dieter R. Brill, Sean A. Hayward

We analyze the global structure of a family of Einstein-Maxwell solutions parametrized by mass, charge and cosmological constant. In a qualitative classification there are: (i) generic black-hole solutions, describing a Wheeler wormhole in a closed cosmos of spatial topology $S^2\times S^1$; (ii) generic naked-singularity solutions, describing a pair of ``po

K. B. Lauritsen, C. Moukarzel, H. J. Herrmann

We investigate random lattices where the connectivities are determined by the Voronoi construction, while the location of the points are the dynamic degrees of freedom. The Voronoi random lattices with an associated energy are immersed in a heat bath and investigated using a Monte Carlo simulation algorithm. In thermodynamic equilibrium we measure coordinati

Hans-Walter Rix, Marcia J. Rieke

We present optical and IR surface photometry of M51 (NGC~5194) at B~V~R~I~J~K and CO$(2.3μ)$. These data are used to establish whether K-band ($2.2μ$) images of spiral galaxies provide reliable maps of stellar surface mass density features such as massive spiral arms or bars. The main distorting agents in the mapping at shorter wavelengths are dust extinctio

Anne A. Thoul, John N. Bahcall, Abraham Loeb

We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multi-component fluid, including the residual heat-flow terms. No approximation is made concerning the relative concentrations and no restriction is placed on the number of elements considered. We give improv

James B. Hartle

These are the author's lectures at the 1992 Les Houches Summer School, "Gravitation and Quantizations". They develop a generalized sum-over-histories quantum mechanics for quantum cosmology that does not require either a preferred notion of time or a definition of measurement. The "post-Everett" quantum mechanics of closed systems is revi

M. Caselle, A. D'Adda, L. Magnea, S. Panzeri

We calculate the partition functions of QCD in two dimensions on a cylinder and on a torus in the gauge $\partial_{0} A_{0} = 0$ by integrating explicitly over the non zero modes of the Fourier expansion in the periodic time variable. The result is a one dimensional Kazakov-Migdal matrix model with eigenvalues on a circle rather than on a line. We prove that

Paul A. Pearce, Yu-kui Zhou

Intertwiners between \ade lattice models are presented and the general theory developed. The intertwiners are discussed at three levels: at the level of the adjacency matrices, at the level of the cell calculus intertwining the face algebras and at the level of the row transfer matrices. A convenient graphical representation of the intertwining cells is intr

O. Bostrom, M. Miller, L. Smolin

We propose a new discrete approximation to the Einstein equations, based on the Capovilla-Dell-Jacobson form of the action for the Ashtekar variables. This formulation is analogous to the Regge calculus in that the curvature has support on sets of measure zero. Both a Lagrangian and Hamiltonian formulation are proposed and we report partial results about the

C. Pinheiro, G. O. Pires, F. A. B. Rabelo de Carvalho

A Maxwell-Chern-Simons field is minimally coupled to 3D-gravity. Feynman rules are written down and 1-loop corrections to the gauge-field self-energy are calculated. Transversality is verified and gauge-field dynamical mass generation does not take place.

Noureddine Mohammedi

It is shown that gauged nonlinear sigma models can be always deformed by terms proportional to the field strength of the gauge fields (nonminimal gauging). These deformations can be interpreted as perturbations, by marginal operators, of conformal coset models. When applied to the SL(2,R)*SU(2)/[U(1)*U(1)] WZWN model, a large class of four-dimensional curved

Noriaki Ikeda, Izawa K. -I

We construct a gauge theory based on general nonlinear Lie algebras. The generic form of `dilaton' gravity is derived from nonlinear Poincar{\' e} algebra, which exhibits a gauge-theoretical origin of the non-geometric scalar field in two-dimensional gravitation theory.

P. Ginsparg, Gregory Moore

Emphasis is on 2d target space (c=1 coupled to gravity). Contents: 0. Introduction, Overview, and Purpose 1. Loops and States in Conformal Field Theory 2. 2D Euclidean Quantum Gravity I: Path Integral Approach 3. Brief Review of the Liouville Theory 4. 2D Euclidean Quantum Gravity II: Canonical Approach 5. 2D Critical String Theory 6. Discretized surfaces, m

Yoichro Matsumura, Norisuke Sakai, Hiroshi Shirokura

Macroscopic loop amplitudes are obtained for the dilation gravity in two-dimensions. The dependence on the macroscopic loop length $l$ is completely determined by using the Wheeler-DeWitt equation in the mini-superspace approximation. The dependence on the cosmological constant $Λ$ is also determined by using the scaling argument in addition.

John S. Hagelin, S. Kelley, Toshiaki Tanaka

We present the most general supersymmetric amplitude for \kkb\/ and \bbb\/ mixing resulting from gluino box diagrams. We use this amplitude to place general constraints on the magnitude of flavor-changing squark mass mixings, and compare these constraints to theoretical predictions both in and beyond the Minimal Supersymmetric Standard Model.

Gonen Gomelski, Marek Karliner, Stephen B. Selipsky

It has been conjectured that at distances smaller than the confinement scale but large enough to allow for nonperturbative effects, QCD is described by an effective $SU(N_c {\times} N_f)_L\times SU(N_c {\times} N_f)_R$ chiral Lagrangian. The soliton solutions of such a Lagrangian are extended objects with spin ${1\over 2}$. For $N_c{=}3$, $N_f{=}3$ they are

J. Lopez, D. Nanopoulos, K. Yuan

We investigate the question of the proper thermal averaging of neutralino annihilation amplitudes which possess poles and thresholds, as they impact on the calculated neutralino relic density and therefore on the cosmological viability of supersymmetric models. We focus on two typical resonances, namely the $Z$ boson and the lightest Higgs boson ($h$). In th

R. K. Schaefer, T. K. Gaisser, T. S. Stanev

A precision measurement of atmospheric electron fluxes has been performed on a Japanese commercial airliner (Enomoto, {\it et al.}, 1991). We have performed a monte carlo calculation of the cosmic ray secondary electron fluxes expected in this experiment. The monte carlo uses the hadronic portion of our neutrino flux cascade program combined with the electro

Katherine Benson, Martin Bucher

It has been pointed out that cosmic string solutions can exist in gauge field theories with broken symmetry even when $π_1(G/H)$ is trivial. The stability of such semilocal defects is not guaranteed by topology and depends on dynamical considerations. In the literature it has been tacitly assumed that if stable, such strings would form in the Early Universe

Jiang Liu

We present a phenomenological description for an unstable fermion based upon one-loop renormalization of quantum field theory. It is emphasized that wave function renormalization can introduce important $CP$-conserving and $CP$-violating phases. Implications for the study of $CP$ violation are examined. Applications are given to $CP$-violating asymmetries in

Göran Fäldt, Per Osland

We evaluate, in the high-energy limit, $s\gg|t|\gg m^2\ggλ^2$, the sum of amplitudes corresponding to a class of Feynman diagrams describing two-loop virtual photonic corrections to Bhabha scattering. The diagrams considered are box and crossed box diagrams with an extra photon decorating one of the fermion lines. The mathematical method employed is that of

Miriam Leurer

We derive new bounds on scalar leptoquark couplings from K^0 K^0 bar, D^0 D^0 bar and B^0 B^0 bar mixing. Although leptoquarks contribute to these processes only at one loop, their contribution is large, due to the lack of GIM cancelation. Our bounds have two important features: (i) They bound g^4/M^2, in contrast to the hitherto known bounds on g^2/M^2, and

D. Grecu, Anca Visinescu

A ri proof of the effective potential (lattice corrections included) deduced by Trullinger and Sasaki is given. Using asymptotic methods from the theory of differential equations depending on a large parameter, the lattice corrections to the kink and kink-kink contributions to the free energy are calculated. The results are in complete agreement with a first

Jarmo Hietarinta, Seppo Mikkola

We have investigated the appearance of chaos in the 1-dimensional Newtonian gravitational three-body system (three masses on a line with $-1/r$ pairwise potential). We have concentrated in particular on how the behavior changes when the relative masses of the three bodies change (with negative total energy). For two mass choices we have calculated 18000 full

M. Capaccioli, E. Cappellaro, E. V. Held, M. Vietri

As a first step of a program aimed to the detection of dark matter (or radial variations of M/L) in early-type galaxies, we report deep spectroscopic observations of the bulge-dominated edge-on S0 galaxy NGC 3115, made at ESO, La Silla, using EFOSC at the 3.6m telescope and EMMI at NTT. Such observations allow measurements of the rotational velocity out to 1

Nathan Poliatzky

We show that the normalization integral for the Schrödinger and Dirac scattering wave functions contains, besides the usual delta-function, a term proportional to the derivative of the phase shift. This term is of zero measure with respect to the integration over momentum variables and can be discarded in most cases. Yet it carries the full information on ph

G. -L. Lin, H. Steger, Y. -P. Yao

We extend our previous work on non-linear realization of the top quark field, which is a consequence of its being much heavier than any other scales. One loop effective Lagrangian to account for virtual top effects is constructed in this article, for processes where there are two external fermions, as well as any number of bosons. Particularly, we focus on t

A. Yu. Boldin, R. A. Sharipov

The dynamical systems of the form $\ddot\bold r=\bold F (\bold r,\dot\bold r)$ in $\Bbb R^n$ accepting the normal shift are considered. The concept of weak normality for them is introduced. The partial differential equations for the force field $\bold F(\bold r,\dot\bold r)$ of the dynamical systems with weak and complete normality are derived.

Claudio Coriano'

We extend previous work on sum rules for the invariant amplitudes of pion Compton scattering by deriving a complete lowest order perturbative spectral function - and its leading non perturbative power corr ections - for a specific combination of the two helicities $(H_1 + H_2)$ of this process. Using some properties of a modified version of the Borel transfo

Robert Bartnik, Gyula Fodor

We prove that the Thin Sandwich Conjecture in general relativity is valid, provided that the data $(g_{ab},\dot g_{ab})$ satisfy certain geometric conditions. These conditions define an open set in the class of possible data, but are not generically satisfied. The implications for the ``superspace'' picture of the Einstein evolution equations are dis

S. P. Sorella, M. Werneck de Oliveira

The Wess-Zumino consistency conditions for Lorentz and diffeomorphism anomalies are discussed by introducing an operator 'delta' which allows to decompose the exterior derivative as a BRS commutator.

Kingman Cheung

The intermediate mass Higgs (IMH) can be abundantly produced through the process $e^-γ\rightarrow W^-Hν$ at TeV $e^-γ$ colliders, which are realized by the laser back-scattering method. We search for the signature of $W^-H \rightarrow (jj)(b\bar b)$ plus missing transverse momentum, with and without considering the $b$-tagging. We also analyse all the potent

H. C. Eggers, P. Lipa, P. Carruthers, B. Buschbeck

We report on a considerable improvement in the technique of measuring multiparticle correlations via integrals over correlation functions. A modification of measures used in the characterization of chaotic dynamical sytems permits fast and flexible calculation of factorial moments and cumulants as well as their differential versions. Higher order correlation

Mona Lubin, Alan D. Sokal

We show that the Wang-Swendsen-Kotecký algorithm for antiferromagnetic $q$-state Potts models is nonergodic at zero temperature for $q=3$ on periodic $3m \times 3n$ lattices where $m,n$ are relatively prime. For $q \ge 4$ and/or other lattice sizes or boundary conditions, the ergodicity at zero temperature is an open question.

C. Arzt, M. B. Einhorn, J. Wudka

We investigate the use of effective Lagrangians to describe the effects on high-precision observables of physics beyond the Standard Model. Using the anomalous magnetic moment of the muon as an example, we detail the use of effective vertices in loop calculations. We then provide estimates of the sensitivity of new experiments measuring the muon's $ g -

Redouane Fakir

It is suggested that gravity waves could, in several cases, be detected by means of already (or shortly to be) available technology, independently of current efforts of detection. The present is a follow-up on a recently suggested detection strategy based on gravity-wave-induced deviations of null geodesics. The new development is that a way was found to pro

Randall D. Kamien

The wandering exponent $ν$ for an isotropic polymer is predicted remarkably well by a simple argument due to Flory. By considering oriented polymers living in a one-parameter family of background tangent fields, we are able to relate the wandering exponent to the exponent in the background field through an $ε$-expansion. We then choose the background field t

C. M. Urry

Daily monitoring of PKS 2155-304 with the IUE satellite throughout November 1991 has revealed dramatic, large-amplitude, rapid variations in the ultraviolet flux of this BL Lac object. Many smaller, rapid flares are superimposed on a general doubling of the intensity. During the five-day period when sampling was roughly continuous, the rapid flaring had an a

Andrzej Sitarz

We show that the description of the electroweak interactions based on noncommutative geometry of a continuous and a discrete space gives no special relations between the Higgs mass and other parameters of the model. We prove that there exists a gauge invariant term, linear in the curvature, which is trivial in the standard differential geometry but nontrivia

Robert Fisch, Janko Gravner, David Griffeath

Each cell of a two-dimensional lattice is painted one of k colors, arranged in a "color wheel." The colors advance (0 to k-1 mod k) either automatically or by contact with at least a threshold number of successor colors in a prescribed local neighborhood. Discrete-time parallel systems of this sort in which color 0 updates by contact and the rest upd

J. Gegenberg, G. Kunstatter

We use a Hodge decomposition and its generalization to non-abelian flat vector bundles to calculate the partition function for abelian and non- abelian BF theories in $n$ dimensions. This enables us to provide a simple proof that the partition function is related to the Ray-Singer torsion defined on flat vector bundles for all odd-dimensional manifolds, and

Denise E. Freed

The dissipative Hofstadter model describes the quantum mechanics of a charged particle in two dimensions subject to a periodic potential, uniform magnetic field, and dissipative force. Its phase diagram exhibits an SL(2,Z) duality symmetry and has an infinite number of critical circles in the dissipation/magnetic field plane. In addition, multi-critical poin

Peter Orland

It is argued that the problems of the cosmological constant, stability and renormalizability of quantum gravity can be solved if the space-time manifold arises through spontaneous symmetry breaking. A ``pre-manifold" model is presented in which many points are connected by random bonds. A set of $D$ real numbers assigned to each point are coupled between

Alexei Yu. Smirnov

The see-saw mechanism of neutrino mass generation may enhance lepton mixing up to maximal even if the Dirac mass matrices of leptons have structure similar to that in the quark sector. Two sets of conditions for such an enhancement are found. The first one includes the see-saw generation of heavy Majorana masses for right-handed neutrinos and a universality

G. E. Brown, C. -H. Lee, M. Rho, V. Thorsson

An effective chiral Lagrangian in heavy-fermion formalism whose parameters are constrained by kaon-nucleon and kaon-nuclear interactions next to the leading order in chiral expansion is used to describe kaon condensation in dense ``neutron star" matter. The critical density is found to be robust with respect to the parameters of the chiral Lagrangian and

Ping Ao

A dynamical theory which incorporates the electron-electron correlations and the effects of external magnetic fields for an electron escaping from a helium surface is presented. The degrees of freedom in the calculation of the escape rate is reduced from $3N$ to 3 as compared with other approach. Explicit expressions for the escape rate in various situations

F. Lucchin, S. Matarrese, A. L. Melott, L. Moscardini

We calculate reduced moments $\overline ξ_q$ of the matter density fluctuations, up to order $q=5$, from counts in cells produced by Particle--Mesh numerical simulations with scale--free Gaussian initial conditions. We use power--law spectra $P(k) \propto k^n$ with indices $n=-3,~-2,~-1,~0,~1$. Due to the supposed absence of characteristic times or scales in

H. J. de Vega, J. Ramírez Mittelbrun, M. Ramón Medrano, N. Sánchez

The string propagation in the two-dimensional stringy black-hole is investigated from a new approach. We completely solve the classical and quantum string dynamics in the lorentzian and euclidean regimes. In the lorentzian case all the physics reduces to a massless scalar particle described by a Klein-Gordon type equation with a singular effective potential.

P. Domitrovich, D. Bückers, H. Müther

Inspired by the model of Nambu and Jona-Lasinio, various Lagrangians are considered for a system of interacting quarks. Employing standard techniques of many-body theory, the scalar part of the quark self-energy is calculated including terms up to second-order in the interaction. Results obtained for the single-particle Green's function are compared with

Grzegorz W. Wasilkowski

We study the average case complexity of multivariate integration and $L_2$ function approximation for the class $F=C([0,1]^d)$ of continuous functions of $d$ variables. The class $F$ is endowed with the isotropic Wiener measure (Brownian motion in Levy's sense). Furthermore, for both problems, only function values are used as data.

Marko Tadic

The main aim of this paper is to present the ideas which lead first to the solution of the unitarizability problem for $\GL(n)$ over nonarchimedean local fields and to the recognition that the same result holds over archimedean local fields, a result which was proved by Vogan using an internal approach. Let us say that the approach that we are going to prese

Gilbert Strang

This note is a very basic introduction to wavelets. It starts with an orthogonal basis of piecewise constant functions, constructed by dilation and translation. The ``wavelet transform'' maps each $f(x)$ to its coefficients with respect to this basis. The mathematics is simple and the transform is fast (faster than the Fast Fourier Transform, which we briefl

Brian R. Hunt, Tim Sauer, James A. Yorke

The authors mention work of Christensen, Mycielski, Tsujii, and others which is closely related to a survey article by the first author [math.FA/9210220].

Ehud Hrushovski, Boris Zilber

We characterize the Zariski topologies over an algebraically closed field in terms of general dimension-theoretic properties. Some applications are given to complex manifold and to strongly minimal sets.

Jerrold R. Griggs

We generalize and solve the $\roman{mod}\,q$ analogue of a problem of Littlewood and Offord, raised by Vaughan and Wooley, concerning the distribution of the $2^n$ sums of the form $\sum_{i=1}^n\varepsilon_ia_i$, where each $\varepsilon_i$ is $0$ or $1$. For all $q$, $n$, $k$ we determine the maximum, over all reduced residues $a_i$ and all sets $P$ consisti

John L. Bryant, Steven C. Ferry, Washington Mio, Shmuel Weinberger

We construct examples of nonresolvable generalized $n$-manifolds, $n\geq 6$, with arbitrary resolution obstruction, homotopy equivalent to any simply connected, closed $n$-manifold. We further investigate the structure of generalized manifolds and present a program for understanding their topology.

Joan S. Birman

In this article we shall give an account of certain developments in knot theory which followed upon the discovery of the Jones polynomial in 1984. The focus of our account will be recent glimmerings of understanding of the topological meaning of the new invariants. A second theme will be the central role that braid theory has played in the subject. A third w

Howard Becker, Alexander S. Kechris

We show that a {\it Borel} action of a Polish group on a standard Borel space is Borel isomorphic to a {\it continuous} action of the group on a Polish space, and we apply this result to three aspects of the theory of Borel actions of Polish groups: universal actions, invariant probability measures, and the Topological Vaught Conjecture. We establish the exi

Denny H. Leung

A Banach space is polyhedral if the unit ball of each of its finite dimensional subspaces is a polyhedron. It is known that a polyhedral Banach space has a separable dual and is $c_0$-saturated, i.e., each closed infinite dimensional subspace contains an isomorph of $c_0$. In this paper, we show that the Orlicz sequence space $h_M$ is isomorphic to a polyhed

J. G. Russo

A discrete string theory --a theory of embeddings from ${\bf Z}\times {\bf Z}_C\to {\bf R}^D$, where $C$ is the number of components of the string-- is explored. The closure of the algebra of constraints (`${\bf Z}_C$-Virasoro algebra') is exhibited. The ${\bf Z}_C$-Virasoro `algebra' is shown to be anomaly free in arbitrary number of target space di

M. Caselle, F. Gliozzi, S. Vinti

We analyze the microscopic, topological structure of the interface between domains of opposite magnetization in 3D Ising model near the critical point. This interface exhibits a fractal behaviour with a high density of handles. The mean area is an almost linear function of the genus. The entropy exponent is affected by strong finite-size effects.

H. Lew, A. Riotto

It has been recently speculated that global symmetries are broken by gravity. We propose a scenario for the generation of the baryon asymmetry in the early Universe in which the domain walls predicted by theories with discrete symmetries become unstable due to these Planck scale effects. The relative motion of the decaying walls can provide a mechanism for t

R. E. Cutkosky, Paul Geiger

A recent general analysis of light-baryon isospin splittings is updated and extended to charmed baryons. The measured $Σ_c$ and $Ξ_c$ splittings stand out as being difficult to understand in terms of two-body forces alone. We also discuss heavy-light mesons; though the framework here is necessarily less general, we nevertheless obtain some predictions that a

Barry R. Holstein

Recently the development of chiral perturbation theory has allowed the generation of rigorous low-energy theorems for various hadronic processes based only on the chiral invariance of the underlying QCD Lagrangian. Herein we examine the experimental implications of chiral symmetry in the regime of electroweak Goldstone boson interactions. Contribution to BNL

Probir Roy

The status of the present precision measurements of electroweak observables is reviewed with specific reference to the radiative parameters $S,T,U$ or equivalently $ε_1,ε_2,ε_3$. The significance of the obliqueness hypothesis is underlined and the importance of the ``local fit'' method of extracting these parameters from the data is emphasized. Possi

D. P. Roy

This is a phenomenological review of $R$ parity violating SUSY models, with particular emphasis on explicit $R$ parity violation.

Anna Hasenfratz, Thomas A. DeGrand

It is expected that the only effect of heavy dynamical fermions in QCD is to renormalize the gauge coupling. We derive a simple expression for the shift in the gauge coupling induced by $N_f$ flavors of heavy fermions. We compare this formula to the shift in the gauge coupling at which the confinement-deconfinement phase transition occurs (at fixed lattice s

Nguyen Hong Chuong, Nguyen Van Hoang

Within the framework of the minimum quadratic Poincare gauge theory of gravity in the Riemann-Cartan spacetime the dynamics of homogeneous anisotropic Bianchi types I-IX spinning-fluid cosmological models is investigated. A basic equation set for these models is obtained and analyzed. In particular, exact solutions for the Bianchi type-I spinning-fluid and B