April 1994 arXiv papers — page 4

M. Alvarez, J. M. F. Labastida

Topological models involving matter couplings to Donaldson-Witten theory are presented. The construction is carried using both, the topological algebra and its central extension, which arise from the twisting of $N=2$ supersymmetry in four dimensions. The framework in which the construction is based is constituted by the superspace associated to these algebr

R. Blumenhagen, W. Eholzer, A. Honecker, K. Hornfeck

We show that quantum Casimir W-algebras truncate at degenerate values of the central charge c to a smaller algebra if the rank is high enough: Choosing a suitable parametrization of the central charge in terms of the rank of the underlying simple Lie algebra, the field content does not change with the rank of the Casimir algebra any more. This leads to ident

Dian-Min Tong, Shan-De Yang, Zhong-Qi Ma

In this note, a new class of representations of the braid groups $B_{N}$ is constructed. It is proved that those representations contain three kinds of irreducible representations: the trivial (identity) one, the Burau one, and an $N$-dimensional one. The explicit form of the $N$-dimensional irreducible representation of the braid group $B_{N}$ is given here

I. Volovich

The problem of introducing a dependence of elements of quantum group on classical parameters is considered. It is suggested to interpret a homomorphism from the algebra of functions on quantum group to the algebra of sections of a sheaf of algebras on a classical manifold as describing such a dependence. It is argued that the functorial point of view of grou

C. Weiss

The off--shell electromagnetic vertex function of pions and kaons is studied in a bosonized Nambu--Jona-Lasinio model with a gauge--invariant proper--time cutoff. The slope of the pion form factor with respect to the pion 4--momentum is found to be equal to the on--shell pion charge radius in the chiral limit. The off--shell slope of the $K^0$ form factor is

José W. F. Valle

Invited Talk at {\sl ICNAPP}, Bangalore, India, Jan. 1994; {\sl Int. School on Cosmological Dark Matter}, Valencia, Oct. 1993; and Gran Sasso meeting on {\sl Solar Neutrino Problem: astrophysics or oscillations?}, march 1994.

V. Semikoz, J. W. F. Valle

We consider active-sterile neutrino conversions in a supernova in the presence of random magnetic field domains. For large enough fields the magnetization of the medium may enhance the active to sterile neutrino conversion rates. Neglecting neutrino transition magnetic moments we show that for KeV neutrino mass squared differences these limits may overcome t

W. S. Carvalho, A. C. B. Antunes

The wave functions in the diquark-quark model for baryons are modified to take into account the effect of the different masses of the quarks in diquark formation. A spatial wave function is introduced multiplying each flavour-spin configuration in the quark-diquark model. Futhermore a numerical coefficient is introduced which weighes the contribution of each

V. Barger, M. S. Berger, P. Ohmann

Unification of the interactions of the Standard Model is possible in its simplest supersymmetric extension. The implications of the $λ_t$ fixed-point solution on the top mass and on Higgs phenomenology is discussed. Expected correlations between the masses of various supersymmetric particles are detailed.

M. Neubert

In a series of three lectures, I review the theory and phenomenology of heavy quark masses and mixing angles and the status of their determination. In addition, I give an introduction to heavy quark symmetry, with the main emphasis on the development of heavy quark effective field theory and its application to obtain a model-independent determination of $|V_

C. Zecher, T. Matsuura, J. J. van der Bij

We study the gluon fusion into pairs of off-shell Z bosons and their subsequent decay into charged lepton pairs at hadron colliders. We do not restrict the intermediate state Z bosons to the narrow width approximation but allow for arbitrary invariant masses. We compare the strength of this process with the known leading order results for q q_bar -> Z Z -> 4

S. D. Bass

Gribov's theory of confinement offers a simple explanaton of the value of the pion nucleon sigma term. There is no need to invoke a large strange quark component in the nucleon.

Kimyeong Lee

We investigate quantum tunneling in the theory of a complex scalar field with a global $U(1)$ symmetry when the charge density of the initial configuration does not vanish. We discuss the possible final configurations and set up the Euclidean path integral formalism to find the bubble nucleation and to study the bubble evolution. For the stationary path, or

A. K. Rebhan

The main role of the Debye screening mass in the perturbative treatment of the electro-weak phase transition is the reduction of the cubic term that determines the strength of a first-order transition. In this note I point out that the standard definition of the Debye mass is unphysical. Its next-to-leading order corrections in resummed perturbation theory a

M. Doser, A. Palano

The experimental information on the search for non $q \bar q$ mesons as glueballs, hybrids and multiquark states is reviewed. Candidate states which are particularly amenable to detailed study by accumulating large samples of $J/ψ$, $η_c$, $χ$ decays at a $τ$-charm factory are discussed.

A. A. Gvozdev, N. V. Mikheev, L. A. Vassilevskaya

The radiative decay of the massive neutrino $ν_i \rightarrow ν_j γ$ in a circularly polarized electromagnetic wave is investigated within the Standard theory with lepton mixing. The decay probability in the wave field does not contain a threshold factor $\sim ( 1 - m_i / m_j )$ as opposed to the decay probability in a vacuum or in a constant uniform external

A. A. Gvozdev, N. V. Mikheev, L. A. Vassilevskaya

In the framework of the Standard Model with lepton mixing the radiative decay $ν_i \rightarrow ν_j γ$ of a neutrino of high ($E_ν\sim 100 \, GeV$) and super-high ($E_ν\ge 1 \, TeV$) energy is investigated in the Coulomb field of a nucleus. Estimates of the decay probability and ``decay cross-section'' for neutrinos of these energies in the electric f

N. V. Mikheev, A. Ya. Parkhomenko

Z-boson decay $Z \rightarrow f\tilde{f}γγ$ in the Standard Model is analysed. The distribution function on the invariant masses of the photon and fermion pairs is calculated in the leading logarithmic approximation. It is shown that this distribution function has a specific shape of a ``crest''. (To be published in Mod.Phys.Lett.A)

V. M. Belyaev

We investigate path integral formalism for continuum theory. It is shown that the path integral for the soft modes can be represented in the form of a lattice theory. Kinetic term of this lattice theory has a standard form and potential term has additional nonlocal terms which contributions should tend to zero in the limit of continuum theory. Contributions

Ted Jacobson

In this short essay we review the arguments showing that black hole entropy is, at least in part, ``entanglement entropy", i.e., missing information contained in correlations between quantum field fluctuations inside and outside the event horizon. Although the entanglement entropy depends upon the matter field content of the theory, it turns out that so

Hans - Jürgen Schmidt

We prove the theorem valid for (Pseudo)-Riemannian manifolds $V_n$: "Let $x \in V_n$ be a fixed point of a homothetic motion which is not an isometry then all curvature invariants vanish at $x$." and get the Corollary: "All curvature invariants of the plane wave metric $$ds \sp 2 \quad = \quad 2 \, du \, dv \, + \, a\sp 2 (u) \, dw \sp 2 \, + \,

Sebastian Eggert, Ian Affleck, Minoru Takahashi

Highly accurate results are presented for the susceptibility, $χ(T)$ of the $s=1/2$ Heisenberg antiferromagnetic chain for all temperatures, using the Bethe ansatz and field theory methods. After going through a rounded peak, $χ(T)$ approaches its asympotic zero-temperature value with infinite slope.

G. G. Li, F. Bridges, J. B. Boyce, T. Claeson

We have used the XAFS (x-ray-absorption fine structure) technique to investigate the local structure about the Cu, Ba, and Tl atoms in orthorhombic Tl-2201 with a superconducting transition temperature T$_c$=60 K. Our results clearly show that the O(1), O(2), Cu, and Ba atoms are at their ideal sites as given by the diffraction measurements, while the Tl and

T. Barnes, J. Riera

We present numerical results for the magnetic susceptibility of a Heisenberg antiferromagnetic spin ladder, as a function of temperature and the spin-spin interaction strengths $J_\perp$ and $J_{||}$. These are contrasted with new bulk limit results for the dimer chain. A fit to the experimental susceptibility of the candidate spin-ladder compound vanadyl py

Michel Carreau, Jorge V. José

We present results from a quantum and semiclassical theoretical study of the $ρ_{xy}$ and $ρ_{xx}$ resistivities of a high mobility 2-D electron gas in the presence of a dilute random distribution of tubes with magnetic flux $Φ$ and radius $R$, for arbitrary values of $k_f R$ and $F=eΦ/h$. We report on novel Aharonov-Bohm type oscillations in $ρ_{xy}$ and $ρ

Gosse Bouma, Gertjan van Noord

We propose a generalization of Categorial Grammar in which lexical categories are defined by means of recursive constraints. In particular, the introduction of relational constraints allows one to capture the effects of (recursive) lexical rules in a computationally attractive manner. We illustrate the linguistic merits of the new approach by showing how it

Josh Frieman

These lectures provide an introductory review of big bang cosmology. I discuss the expanding Friedmann-Robertson-Walker universe, summarizing the observational evidence which has led to its adoption as the `standard' cosmological model and reviewing its basic properties. Subsequent lectures provide an overview of the early universe. The final lectures gi

J. I. Katz, H. A. Toole, S. H. Unruh

We develop a model of SGR in which a supernova leaves planets orbiting a neutron star in intersecting eccentric orbits. These planets will collide in $\sim 10^4$ years if their orbits are coplanar. Some fragments of debris lose their angular momentum in the collision and fall onto the neutron star, producing a SGR. The initial accretion of matter left by the

Vahid Karimipour

There are only two quantum group structures on the space of two by two unimodular matrices, these are the $SL_q(2)$ and the $SL_h(2)$ [9-13] quantum groups. One can not construct a differential geometry on $ SL_q(2)$, which at the same time is bicovariant, has three generators, and satisfies the Liebnitz rule. We show that such a differential geometry exists

V. M. Belyaev

Electromagnetic form factors of the transition $π+γ_{virt.}\ra A_1$ are calculated by QCD sum rules technique with the description of the pion in terms of the set of wave functions of increasing twist. Obtained results are compared with standard QCD sum rule calculations.

Wei Chen, Chigak Itoi

We study a relativistic anyon model with a spin-$j$ matter field minimally coupled to a statistical gauge potential governed by the Chern-Simons dynamics with a statistical parameter $α$. A spin and statistics transmutation is shown in terms of a continuous random walk method. An integer or odd-half-integer part of $α$ can be reabsorbed by change of $j$. We

Per Elmfors, Bo-Sture Skagerstam

The one--loop effective action for a slowly varying electromagnetic field is computed at finite temperature and density using a real-time formalism. We discuss the gauge invariance of the result. Corrections to the Debye mass from an electric field are computed at high temperature and high density. The effective coupling constant, defined from a purely elect

P. Sitko

Statistics transmutations to composite fermions in fractional-quantum-Hall-effect systems are considered in the Hartree-Fock approximation and in the RPA. The Hartree-Fock ground-state energy shows that the transmutations are not energetically preferable. Within the RPA it is found that the system exhibits a fractional quantum Hall effect.

Alexander Moroz

The density of states for a finite or an infinite cluster of scatterers in the case of both electrons and photons can be represented in a general form as the sum over all Krein-Friedel contributions of individual scatterers and a contribution due to the presence of multiple scatterers. The latter is given by the sum over all periodic orbits between different

Alexander MOROZ

In the nonrelativistic case we find that whenever the relation $mc^2/e^2 <X(\al,g_m)$ is satisfied, where $\al$ is a flux in the units of the flux quantum, $g_m$ is magnetic moment, and $X(\al,g_m)$ is some function that is nonzero only for $g_m>2$ (note that $g_m=2.00232$ for the electron), then the matter is unstable against formation of the flux $\al$. Th

M. J. Devlin, A. C. Clapp, J. O. Gundersen, C. A. Hagmann

We present results from a four frequency observation of a 6 x 0.6 degree strip of the sky centered near the star Gamma Ursae Minoris during the fourth flight of the Millimeter-wave Anisotropy eXperiment (MAX). The observation was made with a 1.4 degree peak-to-peak sinusoidal chop in all bands. The FWHM beam sizes were 0.55 +/- 0.05 degrees at 3.5 cm-1 and 0

Alfred Pfitzner, Wolfgang Cassing, Andreas Peter

We adopt a truncated version of two-body dynamics by neglecting three-body correlations, as is supported by microscopic numerical calculations. Introducing orthogonal channel correlations for the pp- and the ph-channel and integrating the latter in terms of vibrational RPA-states we derive a retarded two-body equation. Its solution is nonperturbative with re

J. Duflo, A. P. Zuker

By assuming the existence of a pseudopotential smooth enough to do Hartree-Fock variations and good enough to describe nuclear structure, we construct mass formulae that rely on general scaling arguments and on a schematic reading of shell model calculations. Fits to 1751 known binding energies for N,Z$\geq 8$ lead to RMS errors of 614 keV with 14 parameters

D. Anselmi, P. Fre&#39;, L. Girardello, P. Soriani

In this paper we show that there exists a new class of topological field theories, whose correlators are intersection numbers of cohomology classes in a constrained moduli space. Our specific example is a formulation of 2D topological gravity. The constrained moduli-space is the Poincare&#39; dual of the top Chern-class of the bundle $E_\rightarrow {\cal M}_

E. Corrigan, P. E. Dorey, R. H. Rietdijk, R. Sasaki

The question of the integrability of real-coupling affine toda field theory on a half-line is addressed. It is found, by examining low-spin conserved charges, that the boundary conditions preserving integrability are strongly constrained. In particular, for the $a_n\ (n>1)$ series of models there can be no free parameters introduced by the boundary condition

I. M. Gel&#39;fand, M. M. Smirnov

Developing ideas based on combinatorial formulas for characteristic classes we introduce the algebra modeling secondary characteristic classes associated to $N$ connections. Certain elements of the algebra correspond to the ordinary and secondary characteristic classes.That construction allows us to give easily the explicit formulas for some known secondary

K. Okumura

A compact graph rule for the effective action $Γ[ϕ]$ of a local composite operator is given in this paper. This long-standing problem of obtaining $Γ[ϕ]$ in this case is solved directly without using the auxiliary field. The rule is first deduced with help of the inversion method, which is a technique for making the Legendre transformation perturbatively. It

Kimball A. Milton

The finite-element approach to lattice field theory is both highly accurate (relative errors $\sim1/N^2$, where $N$ is the number of lattice points) and exactly unitary (in the sense that canonical commutation relations are exactly preserved at the lattice sites). In this talk I construct matrix elements for dynamical variables and for the time evolution ope

Martin J. Savage

We examine the role of the $Λ(1405)$ in kaon-nucleon scattering lengths using chiral perturbation theory. The leading nonanalytic SU(3) corrections reduce the coupling of the $Λ(1405)$ to $KN$ compared to $Σπ$. S-wave $K^-p$ scattering is the only channel significantly affected by the $ Λ(1405)$ pole which substantially cancels against the leading term fixed

Alan R. White

Leading plus next-to leading log results for the Regge limit of massless Yang-Mills theories are reproduced by reggeon diagrams in which the Regge slope $α&#39; \to 0$ and reggeon amplitudes satisfy Ward identity constraints at zero transverse momentum. Using reggeon unitarity together with multiple discontinuity theory a complete set of such diagrams can be

Michael Gronau, Oscar F. Hernandez, David London, Jonathan L. Rosner

The decays $B \to PP$, where $P$ denotes a pseudoscalar meson, are analyzed, with emphasis on charmless final states. Numerous triangle relations for amplitudes hold within SU(3) symmetry, relating (for example) the decays $B^+ \to π^+ π^0,~ π^0 K^+$, and $π^+ K^0$. Such relations can improve the possibilities for early detection of $CP$-violating asymmetrie

Michael Gronau, Jonathan L. Rosner, David London

The theory of $CP$ violation based on phases in weak couplings in the Cabibbo-Kobayashi-Maskawa (CKM) matrix requires the phase $γ\equiv {\rm Arg~} V^*_{ub}$ (in a standard convention) to be nonzero. A measurement of $γ$ is proposed based on charged $B$ meson decay rates to $π^+ K^0$, $π^0 K^+$, $π^+ π^0$, and the charge-conjugate states. The corresponding b

Oscar F. Hernandez, David London, Michael Gronau, Jonathan L. Rosner

Flavor SU(3) symmetry implies certain relations among $B$-decay amplitudes to $ππ$, $πK$ and $K {\bar K}$ final states, when annihilation-like diagrams are neglected. Using three triangle relations, we show how to measure the weak CKM phases $α$ and $γ$ using time-independent rate measurements only. In addition, one obtains all the strong final-state phases

M. Kraemer, J. Kuehn, M. L. Stong, P. M. Zerwas

We analyze the prospects of measuring the parity of Higgs particles in the Standard Model and its supersymmetric extensions. Higgs decays are discussed in this context as well as production processes including, in particular, the fusion of Higgs particles in linearly polarized photon--photon collisions.

R. Barbieri, G. Dvali, A. Strumia

We describe a class of supersymmetric unified models with the following properties: i) the full breaking of the gauge group is achieved by Higgs fields in the fundamental representation; ii) the correct unification of the strong and electroweak coupling constants is obtained without the need of any intermediate scale; iii) the problems of the doublet-triplet

S. Narison, G. M. Shore, G. Veneziano

An approach to deep inelastic scattering is described in which the matrix elements arising from the operator product expansion are factorised into composite operator propagators and proper vertex functions. In the case of polarised $\m p$ scattering, the composite operator propagator is identified with the square root of the QCD topological susceptibility $\

G. N. Martin, F. D. Mazzitelli

We show that in a large class of two dimensional models with conformal matter fields, the semiclassical cosmological solutions have a weak coupling singularity if the classical matter content is below a certain threshold. This threshold and the approach to the singularity are model-independent. When the matter fields are not conformally invariant, the singul

Masayuki Tanimoto

The conditions for the existence of Killing-Yano tensors, which are closely related to the appearance of non-generic world-line SUSY, are presented for static axisymmetric spacetimes. Imposing the vacuum Einstein equation, the set of solutions admitting Killing-Yano tensors is considered. In particular, it is shown that static, axisymmetric and asymptoticall

Jian Ma, C. Quitmann, R. J. Kelley, H. Berger

We present the first detailed data of the momentum-resolved, temperature dependence of the superconducting gap of $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$, complemented by similar data on the intensity of the photoemission superconducting condensate spectral area. The gap anisotropy between the $Γ-\bar{M}$ and $Γ-X$ directions increases markedly with increasing tem

A. M. S. Macedo

We study the response of the transmission eigenvalue spectrum of disordered metallic conductors to an arbitrary external perturbation. For systems without time-reversal symmetry we find an exact non-perturbative solution for the two-point correlation function, which exhibits a new kind of universal behavior characteristic of disordered conductors. Systems wi

A. M. S. Macedo

We obtain explicit expressions for the correlation functions of transmission and reflection coefficients of coherent electronic waves propagating through a disordered quasi-one-dimensional medium with purely elastic diffusive scattering in the presence of spin-orbit interactions. We find in the metallic regime both large local intensity fluctuations and long

Mads Nielsen, Per Hedegård

We have considered the conductivity properties of a two dimensional electron gas (2DEG) in two different kinds of inhomogeneous magnetic fields, i.e.\ a disordered distribution of magnetic flux vortices, and a periodic array of magnetic flux vortices. The work falls in two parts. In the first part we show how the phase shifts for an electron scattering on an

A. Lastri, F. Dalfovo, L. Pitaevskii, S. Stringari

A detailed study of the dispersion law of surface excitations in liquid \hef at zero temperature is presented, with special emphasis to the short wave length region. The hybridization mechanism between surface and bulk modes is discussed on a general basis, investigating the scattering of slow rotons from the surface. An accurate density functional, accounti

Marco E. Ferrero, Miguel A. Virasoro

We study the replica free energy surface for a spin glass model near the glassy temperature. In this model the simplicity of the equilibrium solution hides non trivial metastable saddle points. By means of the stability analysis performed for one and two real replicas constrained, an interpretation for some of them is achieved.

M. J. Rees, P. Meszaros

The &#39;event&#39; that triggers a gamma ray burst cannot last for more than a few seconds. This is, however, long compared with the dynamical timescale of a compact stellar-mass object ($\sim 10^{-3}$ seconds). Energy is assumed to be released as an outflow with high mean lorentz factor $Γ$. But a compact stellar-mass collapse or merger is, realistically,

J. N. Fry, Adrian L. Melott, Sergei F. Shandarin

We examine the effect of a threshold bias on the power spectrum and the bispectrum in an ensemble of numerical simulations (Gaussian initial perturbations with power law spectra P(k) \sim k^n, n=+1, 0, -1, -2) and compare our results with theoretical predictions. Our simulations are evolved sufficiently that on the scale where we apply the threshold the rms

M. Rainer

Conformal transformations of the following kinds are compared: (1) conformal coordinate transformations, (2) conformal transformations of Lagrangian models for a D-dimensional geometry, given by a Riemannian manifold M with metric g of arbitrary signature, and (3) conformal transformations of (mini-)superspace geometry. For conformal invariance under this tr

Petr Horava

Chern-Simons gauge theory is formulated on three dimensional $Z_2$ orbifolds. The locus of singular points on a given orbifold is equivalent to a link of Wilson lines. This allows one to reduce any correlation function on orbifolds to a sum of more complicated correlation functions in the simpler theory on manifolds. Chern-Simons theory on manifolds is known

Yang Sun, Da Hsuan Feng, Shuxian Wen

Varied signature splitting phenomena in odd proton rare earth nuclei are investigated. Signature splitting as functions of $K$ and $j$ in the angular momentum projection theory is explicitly shown and compared with those of the particle rotor model. The observed deviations from these rules are due to the band mixings. The recently measured $^{169}$Ta high sp

L. Lavoura, Joao P. Silva

We consider a SU(2)$ \otimes $U(1) gauge theory with many scalar doublets, but without fermions. We devise a systematic method of constructing quantities which are invariant under changes of basis of the scalar fields, but acquire a minus sign under a general CP transformation. Those quantities provide a basis-independent way of checking for the existence of

M. Rainer

A finite subgroup of the conformal group SL(2,C) can be related to invariant polynomials on a hypersurface in C^3. The latter then carries a simple singularity, which resolves by a finite iteration of basic cycles of deprojections. The homological intersection graph of this cycles is the Dynkin graph of an ADE Lie group. The deformation of the simple singula

Arnon Dar, Giora Shaviv

In a recent paper Dar and Shaviv (1994) presented results of calculations with an improved standard solar model (SSM) that suggest a standard physics solution to the solar neutrino problem. In a subsequent publication with a similar title Bahcall et al. (1994) have claimed to refute the results obtained by Dar and Shaviv. Here we show that the criticism and

Suzhou HUANG, Marcello LISSIA

Within the framework of the operator product expansion (OPE) and the renormalization group equation (RGE), we show that the temperature and chemical potential dependence of the zeroth moment of a spectral function (SF) is completely determined by the one-loop structure of an asymptotically free theory. This exact result constrains the shape of SF&#39;s, and

Nicholas Dorey, James Hughes, Michael Mattis

We present the complete solution to the so-called ``Yukawa problem&#39;&#39; of the Skyrme model. This refers to the perceived difficulty of reproducing---purely from soliton physics---the usual pseudovector pion-nucleon coupling, echoed by pion coupling to the higher spin/isospin baryons $(I=J=3/2 , 5/2 , \cdots , N_c/2 )$ in a manner fixed by large-$N_c$ g

D. V. Bugg, R. Machleidt

High partial waves for $pp$ and $np$ elastic scattering are examined critically from 210 to 800 MeV. Non-OPE contributions are compared with predictions from theory. There are some discrepancies, but sufficient agreement that values of the $πNN$ coupling constants $g_0^2$ for $π^0$ exchange and $g^2_{c}$ for charged $π$ exchange can be derived. Results are $

Dharam V. Ahluwalia

In this essay, an {\it ab initio} study of the self/anti-self charge conjugate $(1/2,\,0)\oplus(0,\,1/2)$ representation space is presented. Incompatibility of self/anti-self charge conjugation with helicity eigenstates and gauge interactions is demonstrated. Parity violation is seen as an intrinsic part of the self/anti-self charge conjugate construct. From

Kikuo Harigaya

Optical absorption spectra of higher fullerenes (C70 and C76) as well as of C60 are calculated by a tight binding model with a long range Coulomb interaction. A reasonable parameter set gives calculated spectra which are in overall agreement with the experiments of of C60 and C76 in solutions. The variations of the spectral shape are discussed relating with

Hoi-Kwong LO

The scattering of a charged fermion from an electroweak string is studied. Owing to an amplification of the wave function at the core radius, the cross sections for helicity flip processes can be largely enhanced. For $0 <\sin^2 θ_w < 1/2 $ (where $θ_w$ is the Weinberg angle), $ω\sim k \sim m_e$ and $kR \ll 1$, we show that the helicity flip differential cro

A. Candiello, K. Lechner

The $N=1$, $D=10$ Supergravity--Super--Yang--Mills (SUGRA-SYM) theory is plagued by ABBJ gauge and Lorentz anomalies which are cancelled via the Green-Schwarz anomaly cancellation mechanism. Due to the fact that the ABBJ anomalies are not invariant under supersymmetry (SUSY) transformations one concludes that the theory is plagued also by a SUSY anomaly. For

Jouko Mickelsson

The commutator anomalies (Schwinger terms) of current algebras in $3+1$ dimensions are computed in terms of the Wodzicki residue of pseudodifferential operators; the result can be written as a (twisted) Radul 2-cocycle for the Lie algebra of PSDO&#39;s. The construction of the (second quantized) current algebra is closely related to a geometric renormalizati

E. Kiritsis, C. Kounnas

Exact string solutions are presented, providing backgrounds where a dynamical change of topology is occuring. This is induced by the time variation of a modulus field. Some lessons are drawn concerning the region of validity of effective theories and how they can be glued together, using stringy information in the region where the topology changes.

M. Eliashvili

We consider non-unitary similarity transformation, interconnecting the $W_{1+\infty}$ algebra representations for the fractional $\nu=\frac{1}{2p+1}$ and integer $\nu=1$ filling fractions. This transformation corresponds to the introduction of the complex abelian Chern-Simons gauge potentials, in terms of which the field-theoretic description of FQHE can be

the SMC

We have measured the spin-dependent structure function $g_1^p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}^2<Q^2<60\,\mbox{GeV}^2$. Its first moment, $\int_0^1 g_1^p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q^2=10\,\m

Shmuel Lifsches, Saharon Shelah

The monadic second-order theory of trees allows quantification over elements and over arbitrary subsets. We classify the class of trees with respect to the question: does a tree T have a definable choice function (by a monadic formula with parameters)? A natural dichotomy arises where the trees that fall in the first class don&#39;t have a definable choice f

Sabine Koppelberg, Saharon Shelah

We answer three problems by J. D. Monk on cardinal invariants of Boolean algebras. Two of these are whether taking the algebraic density pi(A), resp. the topological density d(A), of a Boolean algebra A commutes with formation of ultraproducts; the third one compares the number of endomorphisms and of ideals of a Boolean algebra.

Daniel Gottesman

Black hole complementarity is incompatible with the existence of traversable wormholes. In fact, traversable wormholes cause problems for any theory where information comes out in the Hawking radiation.

E. Ivanov, A. Sutulin

We define basics of $(4,4)\;\; 2D$ harmonic superspace with two independent sets of $SU(2)$ harmonic variables and apply it to construct new superfield actions of $(4,4)$ supersymmetric two-dimensional sigma models with torsion and mutually commuting left and right complex structures, as well as of their massive deformations. We show that the generic off-she

Z. Zhu, D. G. Caldi

There are infinitely many topological solitons in any given complex affine Toda theories and most of them have complex energy density. When we require the energy density of the solitons to be real, we find that the reality condition is related to a simple ``pairing condition.&#39;&#39; Unfortunately, rather few soliton solutions in these theories survive the

Andrei Matytsin, Alexander A. Migdal

The behaviour of the master field in ``induced QCD&#34; near the edge of its support is studied. An extended scaling domain, where the shape of the master field is a universal function, is found. This function is determined explicitly for the case of dimensions, close to one, and the $D-1$-expansion is constructed. The problem of the meson spectrum correspon

Stéphane OUVRY

One discusses the validity and equivalence of various perturbative approaches for the Aharonov -Bohm and Anyon models.

H. -J. Otto

We review the construction of field operators of the N=1 supersymmetric Liouville theory in terms of the components of a quantized free superfield.

S. M. Kuzenko, S. L. Lyakhovich, A. Yu. Segal

We propose the action for a massive $N$-extended superparticle with a pure (half)integer superspin $Y,~Y = 0, 1/2, 1, 3/2, \ldots$. Regardless of the superspin value, the configuration space is ${\Bbb R}^{4|4N} \times S^2$, where $S^2$ corresponds to spinning degrees of freedom. Being explicitly super-Poincaré invariant, the model possesses two gauge symmetr

Didier Caenepeel, Martin Leblanc

We present an alternative to the Higgs mechanism to generate masses for non-abelian gauge fields in (3+1)-dimensions. The initial Lagrangian is composed of a fermion with current-current and dipole-dipole type self-interactions minimally coupled to non-abelian gauge fields. The mass generation occurs upon the fermionic functional integration. We show that by

A. Hammerschmitt, J. Kripfganz, M. G. Schmidt

We investigate an extension of the standard model with a second Higgs doublet, showing a two stage phase transition. Wash-out of a baryon asymmetry after the phase transition can be easily avoided in this class of models. B+L transitions are more strongly suppressed in the intermediate phase than in the high temperature symmetric phase,however. Therefore, it

Yue-Liang Wu

It is shown that the mechanism of spontaneous symmetry breaking provides not only a mechanism for giving mass to the bosons and the fermions, but also a mechanism for generating CP-phase of the bosons and the fermions. A two-Higgs doublet model with Vacuum CP Violation and Approximate Global $U(1)$ Family Symmetries (AGUFS) is built and may provide one of th

E. Malec, N. Ó Murchadha

Consider a spherically symmetric spacelike slice through a spherically symmetric spacetime. One can derive a universal bound for the optical scalars on any such slice. The only requirement is that the matter sources satisfy the dominant energy condition and that the slice be asymptotically flat and regular at the origin. This bound can be used to derive new

J. Tinka Gammel

In M. Alouani et al., Phys. Rev. Lett. 71, 1415 (1993), the authors performed local-density-approximation (LDA) calculations and fit to the two-band model [J.T. Gammel et al., Phys. Rev. B 45, 6408 (1992)] we proposed for halogen-bridged transition-metal linear-chain compounds ($M$$X$ chains). Based on that fit, the authors argue a hard-core repulsive term m

A. D. Rutenberg, A. J. Bray

We consider the phase-ordering kinetics of one-dimensional scalar systems. For attractive long-range ($r^{-(1+σ)}$) interactions with $σ>0$, ``Energy-Scaling&#39;&#39; arguments predict a growth-law of the average domain size $L \sim t^{1/(1+σ)}$ for all $σ>0$. Numerical results for $σ=0.5$, $1.0$, and $1.5$ demonstrate both scaling and the predicted growth

Claudius Gros, Roser Valenti

We consider projected wavefunctions for the 2D $t-J$ model. For various wavefunctions, including correlated Fermi-liquid and Luttinger-type wavefunctions we present the static charge-charge and spin-spin structure factors. Comparison with recent results from a high-temperature expansion by Putikka {\it et al.} indicates spin-charge separation at small length

Werner Fischer, Hajo Leschke, Peter Mu&#34;ller

A new class of random quantum--dynamical systems in continuous space is introduced and studied in some detail. Each member of the class is characterized by a Hamiltonian which is the sum of two parts. While one part is deterministic, time--independent, and quadratic, the Weyl--Wigner symbol of the other part is a homogeneous Gaussian random field which is de

R. M. CHANDLER-BURNS

S92 research was begun in 1987 to analyze word frequencies in present-day Spanish for making speech pathology evaluation tools. 500 2,000-word samples of children, adolescents and adults&#39; language were input between 1988-1991, calculations done in 1992; statistical and Lewandowski analyses were carried out in 1993.

Arjendu K. Pattanayak, William C. Schieve

The time-dependent variational principle using generalized Gaussian trial functions yields a finite dimensional approximation to the full quantum dynamics and is used in many disciplines. It is shown how these &#39;semi-quantum&#39; dynamics may be derived via the Ehrenfest theorem and recast as an extended classical gradient system with the fluctuation vari

Eric L. N. Jensen, Robert D. Mathieu, Gary A. Fuller

We have made sensitive 800-micron continuum observations of low-mass, pre-main sequence (PMS) binary stars with projected separations less than 25 AU in Taurus-Auriga to study disks in the young binary environment. We did not detect any of the observed binaries, with typical 3-sigma upper limits of about 30 mJy. Combining our observations with previous 1300-

Renyue Cen

The mass and velocity distributions in the outskirts ($0.5-3.0h^{-1}$Mpc) of clusters of galaxies are examined for a suite of cosmogonic models utilizing large-scale Particle-Mesh (PM) simulations ($500^3$ cells, $250^3$ particles and box size of $100h^{-1}$Mpc, giving a nominal resolution of $0.2h^{-1}$Mpc with the true resolution about $0.5h^{-1}$Mpc). Thr

L. Chernin, C. Masson, E. M. Gouveia Dal Pino, W. Benz

We have used 3-D smoothed particle hydrodynamical simulations to study the basic properties of the outflow that is created by a protostellar jet in a dense molecular cloud. The dynamics of the jet/cloud interaction is strongly affected by the cooling in the shocked gas behind the bow shock at the head of the jet. We show that this cooling is very rapid, with