arXiv papers from April 1996

Neville R. Jones, Dongsheng Liu

The radiative meson decays $V\to P\gamma$ and $P\to \gamma\gamma$ are analyzed using the quark triangle diagram. Experimental data yield well determined estimates of the universal quark-antiquark-meson couplings $g_{Vq\bar{q}'}$ and $g_{Pq\bar{q}'}$ for the light meson sector. Also predictions for the ratios of neutral to charged heavy meson decay coupling c

Savas Dimopoulos, Scott Thomas, James D. Wells

The signatures for low energy supersymmetry breaking at the Tevatron are investigated. It is natural that the lightest standard model superpartner is an electroweak neutralino, which decays to an essentially massless Goldstino and photon, possibly within the detector. In the simplest models of gauge-mediated supersymmetry breaking, the production of right-ha

N. Dupuis

We show how Fermi liquid theory results can be systematically recovered using a renormalization group (RG) approach. Considering a two-dimensional system with a circular Fermi surface, we derive RG equations at one-loop order for the two-particle vertex function $\Gamma $ in the limit of small momentum (${\bf Q}$) and energy ($\Omega $) transfer and obtain t

I. M. Krichever, D. H. Phong

We provide a unified construction of the symplectic forms which arise in the solution of both N=2 supersymmetric Yang-Mills theories and soliton equations. Their phase spaces are Jacobian-type bundles over the leaves of a foliation in a universal configuration space. On one hand, imbedded into finite-gap solutions of soliton equations, these symplectic forms

J. T. Londergan, G. Q. Liu, A. W. Thomas

We investigate the information which could be obtained from Drell-Yan processes with sufficiently intense beams of charged kaons on isoscalar targets. It is found that combinations of $K^+$ and $K^-$ Drell-Yan measurements on isoscalar nuclear targets would allow one to extract the kaon sea quark distributions. These cross sections are also sensitive to the

B. Bailey, E. L. Berger, L. E. Gordon

The two particle inclusive cross section for the reaction $p +\bar{p}\rightarrow \gamma + c + X$ is studied in perturbative quantum chromodynamics at order $O(\alpha ^2_s)$, for large values of the transverse momentum of the prompt photon and charm quark. Two different techniques are used in performing the phase-space integrals; the first is purely analytica

J. T. Londergan, Alex Pang, A. W. Thomas

Recent experiments by the HERMES group at HERA are measuring semi-inclusive electroproduction of pions from deuterium. We point out that by comparing the production of $\pi^+$ and $\pi^-$ from an isoscalar target, it is possible, in principle, to measure charge symmetry violation in the valence quark distributions of the nucleons. It is also possible in the

Michael R. Douglas

We prove that self-dual gauge fields in type I superstring theory are equivalent to configurations of Dirichlet 5-branes, by showing that the world-sheet theory of a Dirichlet 1-brane moving in a background of 5-branes includes an ``ADHM sigma model.'' This provides an explicit construction of the equivalent self-dual gauge field. We also discuss type II.

Rabindra N. Mohapatra, Andrija Rasin

We analyze the minimal supersymmetric left-right model with non-re\-nor\-malizable interactions induced by higher scale physics and study its {\it CP} violating properties. We show that it: (i) solves the strong {\it CP} problem; (ii) predicts the neutron electric dipole moment well within experimental limits (thus solving the usual SUSY {\it CP} problem). I

Zhong Tang

We develop a new transformation theory in quantum physics, where the transformation operators, defined in the infinite dimensional Hilbert space, have right-unitary inverses only. Through several theorems, we discuss the properties of state space of such operators. As one application of the right-unitary transformation (RUT), we show that using the RUT metho

M. Franz, C. Kallin, A. J. Berlinsky

Strong evidence is presented for the localization of low energy quasiparticle states in disordered $d$-wave superconductors. Within the framework of the Bogoliubov-de Gennes (BdG) theory applied to the extended Hubbard model with a finite concentration of non-magnetic impurities, we carry out a fully self-consistent numerical diagonalization of the BdG equat

J. P. Rodriguez

The issue of the decoupling of extreme type-II superconducting thin films ($\lambda_L\rightarrow\infty$) with weakly Josephson-coupled layers in magnetic field parallel to the layers is considered via the corresponding frustrated $XY$ model used to describe the mixed phase in the critical regime. For the general case of arbitrary field orientations such that

Rachel Wortis, David A. Huse

We have simulated the time-dependent Ginzburg-Landau equation with thermal fluctuations, to study the nonlocal dc conductivity of a superconducting film. Having examined points in the phase diagram at a wide range of temperatures and fields below the mean-field upper critical field, we find a portion of the vortex-liquid regime in which the nonlocal ohmic co

J. A. de Azcárraga, F. Rodenas

The differential calculus on `non-standard' $h$-Minkowski spaces is given. In particular it is shown that, for them, it is possible to introduce coordinates and derivatives which are simultaneously hermitian.

Mirim Lee, James W. Dufty, José M. Montanero, Andrés Santos

Uniform Shear Flow is a prototype nonequilibrium state admitting detailed study at both the macroscopic and microscopic levels via theory and computer simulation. It is shown that the hydrodynamic equations for this state have a long wavelength instability. This result is obtained first from the Navier-Stokes equations and shown to apply at both low and high

A. Riotto, I. I. Tkachev

We calculate the strength of symmetry restoration effects in highly non-equilibrium states which can arise, for example, during preheating after inflation. We show that in certain parameter range the one-loop results are unstable, requiring summation of multiloop diagrams. We solve this problem for the $O(N)$ model in the large $N$-limit and show that the sy

R. V. E. Lovelace, Tom Chou

We consider accretion disks consisting of counter-rotating gaseous components with an intervening shear layer. Configurations of this type may arise from the accretion of newly supplied counter-rotating gas onto an existing co-rotating gas disk. For simplicity we consider the case where the gas well above the disk midplane is rotating with angular rate $+\Om

Andrei Mikheev, Steven Finch

In this paper we describe an architecture and functionality of main components of a workbench for an acquisition of domain knowledge from large text corpora. The workbench supports an incremental process of corpus analysis starting from a rough automatic extraction and organization of lexico-semantic regularities and ending with a computer supported analysis

D. Delepine, J. -M. Gerard, R. Gonzalez Felipe, J. Weyers

The possibility of creating baryon asymmetry at the electroweak phase transition in the minimal supersymmetric standard model is considered for the case when right-handed squarks are much lighter than left-handed ones. It is shown that the usual requirement v(T_c)/T_c > 1 for baryogenesis can be satisfied in a range of the parameters of the model, consistent

Alexei Yu. Smirnov, Francesco Vissani

Stellar objects (including our Sun, other stars of main sequence, white dwarfs, neutron stars etc.) contain strongly degenerate low energy sea of neutrinos (in neutron stars) or antineutrinos. The presence of this sea leads due to Pauli principle and thermal effects to effective blocking of the long-range neutrino forces. This blocking can resolve the proble

A. Kashlinsky, J. C. Mather, S. Odenwald, M. Hauser

This paper is devoted to studying the CIB through its correlation properties. We studied the limits on CIB anisotropy in the near IR (1.25, 2.2, and 3.5 \um, or $J,\;K,\;L$) bands at a scale of 0.7\deg\ using the COBE\footnote{ The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development

Andrei Mikheev

Words unknown to the lexicon present a substantial problem to part-of-speech tagging. In this paper we present a technique for fully unsupervised statistical acquisition of rules which guess possible parts-of-speech for unknown words. Three complementary sets of word-guessing rules are induced from the lexicon and a raw corpus: prefix morphological rules, su

A. Kashlinsky, J. C. Mather, S. Odenwald, M. G. Hauser

We outline a new method for estimating the cosmic infrared background using the spatial and spectral correlation properties of infrared maps. The cosmic infrared background from galaxies should have a minimum fluctuation of the order of 10\% on angular scales of the order of 1\deg. We show that a linear combination of maps at different wavelengths can greatl

A. Nersessian, V. Ter-Antonyan, M. Tsulaia

It is shown, that the reduction of the circular quantum oscillator by the $Z_2$-group action results to the two systems: a two-dimensional hydrogen atom, and a ``charge - charged magnetic vortex" one, with the spin $\frac 12$. Analogously, the $Z_N$-reduction of the two-dimensional system with the central potential $r^{2(N-1)}$ results into $N$ bound ``charg

Itzhak Bars

Using a global superalgebra with 32 fermionic and 528 bosonic charges, many features of p-brane dualities and hidden dimensions are discussed.

Andrei Mikheev

One of the problems in part-of-speech tagging of real-word texts is that of unknown to the lexicon words. In Mikheev (ACL-96 cmp-lg/9604022), a technique for fully unsupervised statistical acquisition of rules which guess possible parts-of-speech for unknown words was proposed. One of the over-simplification assumed by this learning technique was the acquisi

Fernando Quevedo, Carlo Trugenberger

We study the different phases of field theories of compact antisymmetric tensors of rank $h-1$ in arbitrary space-time dimensions $D=d+1$. Starting in a `Coulomb' phase, topological defects of dimension $d-h-1$ ($(d-h-1)$-branes) may condense leading to a generalized `confinement' phase. If the dual theory is also compact the model may also have a third, gen

D. Espriu, R. Tarrach

We point out that, contrary to what is believed to hold for QCD, renormalons are genuine in QED; i.e. the ambiguities which come with them do not require cancellation by hypothetical non-perturbative contributions. They are just the ambiguities characteristic of any trivial ---and thus effective--- theory. If QED remained an isolated theory up to an energy c

Yubing Luo

We present a complete and detailed derivation of the finite lattice spacing corrections to staggered fermion matrix elements. Expanding upon arguments of Sharpe, we explicitly implement the Symanzik improvement program demonstrating the absence of order $a$ terms in the Symanzik improved action. We propose a general program to improve fermion operators to re

Hyun-Chul Kim, Maxim V. Polyakov, Klaus Goeke

The tensor charges of the nucleon are calculated in the framework of the SU(3) chiral quark soliton model. The rotational $1/N_c$ and strange quark mass corrections are taken into account up to linear order. We obtain the following numerical values of the tensor charges: $\delta u=1.12$, $\delta d=-0.42$, and $\delta s=-0.008$. In contrast to the axial charg

A. Bianconi, M. Radici

The advent of new electron accelerators with few-GeV beam energies makes the (e,e'p) reaction a promising tool for investigating new aspects of the electromagnetic interaction. To this purpose it is crucial to set the scale of Final-State Interactions (FSI) at high ejectile energies. We have analyzed the constraints which allow for a meaningful generalizatio

Chr. V. Christov, A. Blotz, H. -C. Kim, P. Pobylitsa

The present review gives a survey of recent developments and applications of the Nambu--Jona-Lasinio model with $N_f=2$ and $N_f=3$ quark flavors for the structure of baryons. The model is an effective chiral quark theory which incorporates the SU(N$_f$)$_L\otimes$SU(N$_f$)$_R\otimes$U(1)$_V$ approximate symmetry of Quantum chromodynamics. The approach descr

Giampiero Esposito, Alexander Yu. Kamenshchik

This paper studies the role of the axial gauge in the semiclassical analysis of simple supergravity about the Euclidean four-ball, when non-local boundary conditions of the spectral type are imposed on gravitino perturbations at the bounding three-sphere. Metric perturbations are instead subject to boundary conditions completely invariant under infinitesimal

S. Hesselbach, H. Fraas

We study the production of charginos and sneutrinos in electron-photon collisions within the minimal supersymmetric standard model (MSSM). The high energy photons can be generated by Compton backscattering of intense laser pulses off one of the beams of the Next Linear Collider (NLC). This process could offer a significant opportunity to identify sneutrinos,

M. Ciuchini, E. Gabrielli, G. F. Giudice

We consider the possibility of having a large branching ratio for the decay $b\to s g$ coming from an enhanced Wilson coefficient of the chromomagnetic dipole operator. We show that values of $BR(b\to s g)$ up to $\sim 10\%$ or more are compatible with the constraints coming from the CLEO experimental results on $BR(B\to X_s\gamma)$ and $BR(B\to X_s\phi)$. S

James Rogers

A natural next step in the evolution of constraint-based grammar formalisms from rewriting formalisms is to abstract fully away from the details of the grammar mechanism---to express syntactic theories purely in terms of the properties of the class of structures they license. By focusing on the structural properties of languages rather than on mechanisms for

Alexandru Nica, Roland Speicher

In the free probability theory of Voiculescu two of the most frequently used *-distributions are those of a Haar unitary and of a circular element. We define an $R$-diagonal pair as a generalization of these distributions by the requirement that their two-dimensional $R$-transform (or free cumulants) have a special diagonal form. We show that the class of su

J. Erdmenger, H. Osborn

The implications of conformal invariance, as relevant in quantum field theories at a renormalisation group fixed point, are analysed with particular reference to results for correlation functions involving conserved currents and the energy momentum tensor. Ward identities resulting from conformal invariance are discussed. Explicit expressions for two and thr

Arturo Trujillo, Simon Berry

This paper presents a pruning technique which can be used to reduce the number of paths searched in rule-based bag generators of the type proposed by \cite{poznanskietal95} and \cite{popowich95}. Pruning the search space in these generators is important given the computational cost of bag generation. The technique relies on a connectivity constraint between

C. H. Bennett, T. Mor, J. A. Smolin

An $n$-bit string is encoded as a sequence of non-orthogonal quantum states. The parity bit of that $n$-bit string is described by one of two density matrices, $\rho_0^{(n)}$ and $\rho_1^{(n)}$, both in a Hilbert space of dimension $2^n$. In order to derive the parity bit the receiver must distinguish between the two density matrices, e.g., in terms of optim

Valerii M. Vinokur, M. Cristina Marchetti, Lee-Wen Chen

We discuss the low-temperature dynamics of an elastic manifold driven through a random medium. For driving forces well below the $T=0$ depinning force, the medium advances via thermally activated hops over the energy barriers separating favorable metastable states. We show that the distribution of waiting times for these hopping processes scales as a power-l

I. F. Ginzburg, D. Yu. Ivanov

We consider two coupled problems. We study the dependence on photon virtuality $Q^2$ for the semihard quasi--elastic photoproduction of neutral vector mesons on a quark, gluon or real photon (at $s\gg p_{\bot}^2,\;Q^2; \; p_{\bot}^2\gg \mu^2 \approx (0.3$ GeV)$^2$). To this end we calculate the corresponding amplitudes (in an analytical form) in the lowest n

Isamu Nakamura, Kiyotomo Kawagoe

Once a light Higgs boson is discovered at a future e+e- collider, the next target at the collider will be precise measurements of the Higgs boson properties. In this paper we report a simulation study on the measurement of the ratio Br(H->cc,gg)/Br(H->bb) at center of mass energy of 300 GeV, and show the possibility to constrain MSSM parameters from the meas

Detlef Lehmann

The propagator for a noninteracting many electron system in a constant magnetic field in three space time dimensions is computed. This formula and the results of [FT1,2] are used to give a microscopic derivation of a BCS-equation with magnetic field. It is shown that this equation has no solution if the magnetic field is sufficiently large. Perturbation theo

H. Awata, H. Kubo, Y. Morita, S. Odake

Primary fields of the $q$-deformed Virasoro algebra are constructed. Commutation relations among the primary fields are studied. Adjoint actions of the deformed Virasoro current on the primary fields are represented by the shift operator $\Theta_{\xi} f(x)=f(\xi x)$. Four point functions of the primary fields enjoy the connection formula associated with the

Roland A. Puntigam, Harald H. Soleng

Cosmic strings, as topological spacetime defects, show striking resemblance to defects in solid continua: distortions, which can be classified into disclinations and dislocations, are line-like defects characterized by a delta function-valued curvature and torsion distribution giving rise to rotational and translational holonomy. We exploit this analogy and

R. Cowsik, Charu Ratnam, P. Bhattacharjee

The self-consistent spatial distribution of particles of Galactic dark matter is derived including their own gravitational potential, as also that of the visible matter of the Galaxy. In order to reproduce the observed rotation curve of the Galaxy the value of the dispersion velocity of the dark matter particles, $\rmsveldm$, should be $\sim 600\kmps$ or lar

P. Lemmens, B. Eisener, M. Brinkmann, L. V. Gasparov

Raman experiments on the spin-Peierls compound CuGeO$_3$ and the substituted (Cu$_{1- x}$,Zn$_x$)GeO$_3$ and Cu(Ge$_{1-x}$,Ga$_x$)O$_3$ compounds were performed in order to investigate the response of specific magnetic excitations of the one-dimensional spin-1/2 chain to spin anisotropies and substitution-induced disorder. In pure CuGeO$_3$, in addition to n

I. Bakas, K. Sfetsos

String propagation on D-dimensional curved backgrounds with Lorentzian signature is formulated as a geometrical problem of embedding surfaces. When the spatial part of the background corresponds to a general WZW model for a compact group, the classical dynamics of the physical degrees of freedom is governed by the coset conformal field theory SO(D-1)/SO(D-2)

Alexandru Nica, Roland Speicher

Let $a_{1},...,a_{n}, b_{1},...,b_{n}$ be random variables in some (non-commutative) probability space, such that $\{a_{1}, ..., a_{n} \}$ is free from $\{b_{1}, ..., b_{n} \}$. We show how the joint distribution of the $n$-tuple $(a_{1} b_{1}, ..., a_{n} b_{n})$ can be described in terms of the joint distributions of $(a_{1}, ..., a_{n})$ and $(b_{1}, >...,

Marek Bozejko, Burkhard Kummerer, Roland Speicher

We examine, for $-1<q<1$, $q$-Gaussian processes, i.e. families of operators (non-commutative random variables) $X_t=a_t+a_t^*$ -- where the $a_t$ fulfill the $q$-commutation relations $a_sa_t^*-qa_t^*a_s=c(s,t)\cdot \id$ for some covariance function $c(\cdot,\cdot)$ -- equipped with the vacuum expectation state. We show that there is a $q$-analogue of the G

M. V. Simkin

It is predicted that the fully frustrated Josephson-junction array on a square lattice with alternating columns of junctions having a reduced critical current $I_{weak}=\mu I_{0}$(with $\mu<1$ and $I_{0}$ the critical current of all other junctions) in certain range of $\mu$ will under increasing of the external current first change from the state with zero

P. J. Rijken, W. L. van Neerven

We present the order $\alpha_s^2$ contributions to the coefficient functions corresponding to the longitudinal fragmentation function $F_L(x,Q^2)$. A comparison with the leading order $\alpha_s$ result for $F_L(x,Q^2)$ shows that the corrections are large and vary from 44\% to 67\% in the region $0.01 < x < 0.9$ at $Q^2=M_Z^2$. Our calculations also reveal t

A. V. Sinitskaya, E. V. Pavlova

The bound states of two particles are studied in frames of non-relativistic quantum field model with current $\times$ current type interaction by analyzing the Bethe-Salpeter amplitudes. The Bethe-Salpeter equations are obtained in closed form. The existence of Goldstone mode corresponding to the spontaneous breaking of additional SU(2) symmetry of the model

Anton Deitmar

We consider the action of a noncompact torus H on the compact quotient G/L, where G is a Lie group containing H and L is a uniform lattice in G. Using harmonic analysis on G we prove a formula relating the compact orbits of H to the action of H on the (infinite dimensional) tangential cohomology. The formula may be viewed as a Lefschetz formula or an equivar

D. Deutsch, A. Ekert, R. Jozsa, C. Macchiavello

Existing quantum cryptographic schemes are not, as they stand, operable in the presence of noise on the quantum communication channel. Although they become operable if they are supplemented by classical privacy-amplification techniques, the resulting schemes are difficult to analyse and have not been proved secure. We introduce the concept of quantum privacy

Patric Uebele, Helmut Hermann

The influence of non-uniform distribution of nuclei on crystallization kinetics of amorphous materials is investigated. This case cannot be described by the well-known Johnson-Mehl-Avrami (JMA) equation, which is only valid under the assumption of a spatially homogeneous nucleation probability. The results of computer simulations of crystallization kinetics

G. Eilam, A. Ioannissyan, P. Singer

We consider the asymmetry in the decay $\Omega^-\rightarrow\Xi^-\gamma$ assuming that a Vector Meson Dominance approach for the $s\rightarrow d\gamma$ transition gives the dominant contribution. Since in this long-distance approximation the decay is due to a single quark transition $s\rightarrow d\gamma$, the angular distribution asymmetry is given by the si

Renata Kallosh, Arvind Rajaraman

We suggest a duality invariant formula for the entropy and temperature of non-extreme black holes in supersymmetric string theory. The entropy is given in terms of the duality invariant parameter of the deviation from extremality and 56 SU(8) covariant central charges. It interpolates between the entropies of Schwarzschild solution and extremal solutions wit

Michael Strickland, Sen-Ben Liao

Effective critical exponents for the \lambda \phi^4 scalar field theory are calculated as a function of the renormalization group block size k_o^{-1} and inverse critical temperature \beta_c. Exact renormalization group equations are presented up to first order in the derivative expansion and numerical solutions are obtained with and without polynomial expan

Ioannis Tsohantjis, Alex C Kalloniatis, Peter D Jarvis

The combinatorics of the BPHZ subtraction scheme for a class of ladder graphs for the three point vertex in $\phi^3$ theory is transcribed into certain connectivity relations for marked chord diagrams (knots with transversal intersections). The resolution of the singular crossings using the equivalence relations in these examples provides confirmation of a p

E. Harikumar, M. Sivakumar

Two different massive gauge invariant spin-one theories in $3+1$ dimensions, one Stuckelberg formulation and the other `$B^{\wedge}F$' theory, with Kalb-Ramond field are shown to be related by duality. This is demonstrated by gauging the global symmetry in the model and constraining the corresponding dual field strength to be zero by a Lagrange multiplier, w

Vijay Balasubramanian, Finn Larsen

We find extremal four dimensional black holes with finite area constructed entirely from intersecting D-branes. We argue that the microscopic degeneracy of these configurations agrees with the Bekenstein-Hawking entropy formula. The absence of solitonic objects in these configurations may make them useful for dynamical studies of black holes.

Xiaohui Fan, David Burstein, Jian-sheng Chen, Jin Zhu

We present nine color CCD intermediate-band spectrophotometry of a two square degree field centered on the old open cluster M67, from 3890$\rm \AA$ to nearly 1$\mu$. These observations are taken as a part of the BATC (Beijing-Arizona-Taipei-Connecticut) Color Survey of the Sky, for both scientific and calibration reasons. With these data we show that the BAT

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod

We report the discovery of two new R Coronae Borealis (RCB) stars in the Large Magellanic Cloud (LMC) using the MACHO project photometry database. The identification of both stars has been confirmed spectroscopically. One is a cool RCB star (T_eff about 5000 K) characterized by very strong Swan bands of C_2 and violet bands of CN, and weak or absent Balmer l

Karl Petersen, Klaus Schmidt

We prove that certain Gibbs measures on subshifts of finite type are nonsingular and ergodic for certain countable equivalence relations, including the orbit relation of the adic transformation (the same as equality after a permutation of finitely many coordinates). The relations we consider are defined by cocycles taking values in groups, including some non

F. Zhou, B. Spivak

It is shown that the conductance of a superconductor-normal metal-superconductor junction can exhibit a significant dependence on the phase of the superconducting order parameter in the situation when the size of the normal region of the junction is much larger than the normal metal coherence length and the critical current of the junction is already exponen

M. V. Simkin

Li (Phys. Rev. Lett. {\bf 69},1819 (1992)) has computed the current-voltage characteristics (CVC) of a disordered two-dimensional (2D) Josephson-junction array and claimed that his data(nonlinear CVC for small temperatures), gives evidence for a finite-temperature phase transition in the 2D gauge-glass model in contradiction to the result of equilibrium simu

A. Kashlinsky, J. C. Mather, S. Odenwald, M. Hauser

The cosmic infrared background from galaxies should have a minimum fluctuation of the order of 10\% on angular scales probed by the DIRBE (Diffuse Infrared Background Experiment) on board COBE (Cosmic Background Explorer). We present the theoretical basis for the analysis and discuss the all-sky all-wavelengths survey that we conducted. We further show that

Alvio Renzini, Angela Bragaglia, Francesco R. Ferraro, Roberto Gilmozzi

Deep Hubble Space Telescope (HST) observations with WFPC2 of the nearby globular cluster NGC 6752 have allowed us to obtain accurate photometry for the cluster white dwarfs (WD). A sample of local WDs of known trigonometric parallax and mass close to that of the cluster WDs have also been observed with WFPC2. Matching the cluster and the local WD sequences p

M. I. Caicedo, A. Restuccia

We present a rigurous disscusion for abelian $BF$ theories in which the base manifold of the $U(1)$ bundle is homeomorphic to a Hilbert space. The theory has an infinte number of stages of reducibility. We specify conditions on the base manifold under which the covarinat quantization of the system can be performed unambiguously. Applications of the formulati

Zhong Tang, David Finkelstein

We introduce topological magnetic field in two-dimensional flat space, which admits a solution of scalar monopole that describes the nontrivial topology. In the Chern-Simons gauge field theory of anyons, we interpret the anyons as the quasi-particles composed of fermions and scalar monopoles in such a form that each fermion is surrounded by infinite number o

Bo-Qiang Ma

We derive simple relations between the polarized and unpolarized valence quark distributions in a light-cone SU(6) quark-spectator model for nucleons. The explicit x-dependent Wigner rotation effect for the light-flavor quarks is calculated. It is shown that the mass difference between the scalar and vector spectators could reproduce the up and down valence

C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod

The MACHO project has been monitoring about ten million stars in the Large Magellanic Cloud in the search for gravitational microlensing events caused by massive compact halo objects (Machos) in the halo of the Milky Way. In our standard analysis, we have searched this data set for well sampled, long duration microlensing lightcurves, detected several microl

Zhong Tang, David Finkelstein

We provide an alternative interpretation for the topological terms in physics by investigating the low-energy gauge interacting system. The asymptotic behavior of the gauge field at infinity indicates that it traces out a closed loop in the infinite time interval: -infinity, + infinity. Adopting Berry's argument of geometric phase, we show that the adiabatic

Francisco Dominguez-Adame

We consider exciton optical absorption in quasiperiodic lattices, focusing our attention on the Fibonacci case as typical example. The absorption spectrum is evaluated by solving numerically the equation of motion of the Frenkel-exciton problem on the lattice, in which on-site energies take on two values according to the Fibonacci sequence. We find that the

Bo-Qiang Ma

A brief summary on the Wigner rotation effect in the understanding of the proton spin ``crisis" related with the Ellis-Jaffe sum rule violation, and on the proton-neutron isospin symmetry breaking explanation of the Gottfried sum rule violation. The proton spin could be fully provided by the spin sum of quarks if one considers the Wigner rotation effect in t

E. Ivanov, A. Sutulin

We define the $SU(2)\times SU(2)$ harmonic superspace analogs of tensor and nonlinear $(4,4)$, $2D$ supermultiplets. They are described by constrained analytic superfields and provide an off-shell formulation of a class of torsionful $(4,4)$ supersymmetric sigma models with abelian translational isometries on the bosonic target. We examine their relation to

David H. Weinberg, Lars Hernquist, Neal Katz

Using cosmological simulations that incorporate gas dynamics and gravitational forces, we investigate the influence of photoionization by a UV radiation background on the formation of galaxies. In our highest resolution simulations, we find that photoionization has essentially no effect on the baryonic mass function of galaxies at $z=2$, down to our resoluti

Soojong Pak, D. T. Jaffe, L. D. Keller

We have mapped the H_2 v=1-0 S(1) (\lambda=2.1215 \micron) emission line along a 400 pc long strip and in a 50 pc region in the Galactic center. There is H_2 emission throughout the surveyed region. The typical de-reddened (A_K = 2.5 mag) surface brightness, about 3 X 10^{-5} ergs/s/cm^2/sr, is similar to the surface brightness in large-scale photon-dominate

Klaus Ziegler, Matthias H. Hettler, Peter J. Hirschfeld

It has been known for some time that, in three dimensions, arbitrarily weak disorder in unconventional superconductors with line nodes gives rise to a nonzero residual density of zero-energy quasiparticle states N(0), leading to characteristic low-temperature thermodynamic properties similar to those observed in cuprate and heavy-fermion systems. In a strict

Neil Turok

Could cosmic structure have formed by the action of causal physics within the standard hot big bang, or was a prior period of inflation required? Recently there has been some discussion of whether causal sources could reproduce the pattern of Doppler peaks of the standard scale-invariant adiabatic theory. This paper gives a rigorous definition of causality,

L. O. Buffon, D. Dalmazi, A. Zadra

We show that the partition function of the super eigenvalue model satisfies an infinite set of constraints with even spins $s=4,6,\cdots,\infty$. These constraints are associated with half of the bosonic generators of the super $\left( W_{\infty \over 2}\oplus W_{{1+\infty}\over 2}\right)$ algebra. The simplest constraint $(s=4)$ is shown to be reducible to

C. -P. Yuan

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

Chongying Dong, James Lepowsky

Twisted vertex operators based on rational lattices have had many applications in vertex operator algebra theory and conformal field theory. In this paper, ``relativized'' twisted vertex operators are constructed in a general context based on isometries of rational lattices, and a generalized twisted Jacobi identity is established for them. This result gener

R. M. Weiner

It is shown that there exists an intimate relationship between Bose Einstein correlations and quantum field theory. On the one hand several essential aspects of BEC cannot be understood and even formulated without second quantization. On the other hand BEC can serve as a unique tool in the investigation of modern field theory and in particular of the standar

Gerald B. Cleaver

I review how traditional grand unified theories, which require adjoint (or higher representation) Higgs fields for breaking to the standard model, can be contained within string theory. The status (as of January 1996) of the search for stringy free fermionic three generation SO(10) SUSY--GUT models is discussed. Progress in free fermionic classification of b

Dan Abramovich

We prove the following theorem: Fibered Power Theorem: Let $X\rar B$ be a smooth family of positive dimensional varieties of general type, with $B$ irreducible. Then there exists an integer $n>0$, a positive dimensional variety of general type $W_n$, and a dominant rational map $X^n_B \das W_n$.

Alexander Russakovskii, Bernard Shiffman

We obtain results on the asymptotic equidistribution of the pre-images of linear subspaces for sequences of rational mappings between projective spaces. As an application to complex dynamics, we consider the iterates $P_k$ of a rational mapping $P$ of $\PP^n$. We show, assuming a condition on the topological degree $\lambda$ of $P$, that there is a probabili

K. C. K. Chan, J. D. E. Creighton, R. B. Mann

We analyze the relationship between quasilocal masses calculated for solutions of conformally related theories. We show that the ADM mass of a static, spherically symmetric solution is conformally invariant (up to a constant factor) only if the background action functional is conformally invariant. Thus, the requirement of conformal invariance places restric

Andrei F. Illarionov, Julian H. Krolik

It is generally supposed that when the "compactness" $l \equiv L\sigma_T/(r m_e c^3)$ in photons above the pair-production threshold is large, few $\gamma$-rays can escape. We demonstrate that even when $l \gg 1$, if the high energy and low energy photons are produced in geometrically-separated regions, many of the $\gamma$-rays can, in fact, escape. Pair-pr

Giampiero Esposito, Alexander Yu. Kamenshchik

This paper studies the semiclassical approximation of simple supergravity in Riemannian four-manifolds with boundary, within the framework of $\zeta$-function regularization. The massless nature of gravitinos, jointly with the presence of a boundary and a local description in terms of potentials for spin ${3\over 2}$, force the background to be totally flat.

Daniel Gottesman

I develop methods for analyzing quantum error-correcting codes, and use these methods to construct an infinite class of codes saturating the quantum Hamming bound. These codes encode $k=n-j-2$ qubits in $n=2^j$ qubits and correct $t=1$ error.

D. Montes, J. Sanz-Forcada, M. J. Fernández-Figueroa, R. Lorente

We present simultaneous H$\alpha$, Na~{\sc i} D$_{1}$, D$_{2}$, and He~{\sc i} D$_{3}$ spectroscopic observations on the RS CVn system UX Ari. We have found a dramatic increase in the excess H$\alpha$ emission equivalent width by a factor of 2 in an interval of 1 day that indicates the beginning of a strong flare in this system. The presence of the He~{\sc i

John Ellis, Douglas Ross

We discuss the one-loop virtual-sparticle corrections to QCD jet cross sections at large $E_T$ and large dijet invariant masses, with reference to present Tevatron and future LHC collider experiments. We find characteristic peaks and dips in the sparticle threshold region, due to interferences with tree-level QCD diagrams. Their magnitudes may be several per

Carlos J. Camacho, Tone Schanke

We consider a two-letter self-avoiding (square) lattice heteropolymer model of N_H (out ofN) attracting sites. At zero temperature, permanent links are formed leading to collapse structures for any fraction rho_H=N_H/N. The average chain size scales as R = N^{1/d}F(rho_H) (d is space dimension). As rho_H --> 0, F(rho_H) ~ rho_H^z with z={1/d-nu}=-1/4 for d=2

V. Cataudella, G. Franzese, M. Nicodemi, A. Scala

A general scheme for devising efficient cluster dynamics proposed in a previous letter [Phys.Rev.Lett. 72, 1541 (1994)] is extensively discussed. In particular the strong connection among equilibrium properties of clusters and dynamic properties as the correlation time for magnetization is emphasized. The general scheme is applied to a number of frustrated s

J. Mohr, M. Geller, D. Fabricant, G. Wegner

We analyze the galaxy population and dynamics of the galaxy cluster Abell 576 using 281 redshifts (230 new), R band CCD galaxy photometry over a 2h^{-1} Mpc by 2h^{-1} Mpc region centered on the cluster, an Einstein IPC image, and an Einstein MPC spectrum. The cluster galaxies with emission lines in their spectra have a larger velocity dispersion and are sig

Kirill N. Alekseev, Gennady P. Berman, David K. Campbell, Ethan H. Cannon

We consider the motion of ballistic electrons in a miniband of a semiconductor superlattice (SSL) under the influence of an external, time-periodic electric field. We use the semi-classical balance-equation approach which incorporates elastic and inelastic scattering (as dissipation) and the self-consistent field generated by the electron motion. The couplin

Marc Dymetman, Max Copperman

We describe two ``semantically-oriented'' dependency-structure formalisms, U-forms and S-forms. U-forms have been previously used in machine translation as interlingual representations, but without being provided with a formal interpretation. S-forms, which we introduce in this paper, are a scoped version of U-forms, and we define a compositional semantics m