June 1995 arXiv papers — page 5

Pascal Vaillant, Michael Checler

The Intelligent Voice Prosthesis is a communication tool which reconstructs the meaning of an ill-structured sequence of icons or symbols, and expresses this meaning into sentences of a Natural Language (French). It has been developed for the use of people who cannot express themselves orally in natural language, and further, who are not able to comply to gr

A. Chekhlov, S. A. Orszag, S. Sukoriansky, B. Galperin

Two-parametric eddy viscosity (TPEV) and other spectral characteristics of two-dimensional (2D) turbulence in the energy transfer sub-range are calculated from direct numerical simulation (DNS) with 512$^2$ resolution. The DNS-based TPEV is compared with those calculated from the test field model (TFM) and from the renormalization group (RG) theory. Very goo

C. Alcock, R. A. Allsman, T. S. Axelrod, D. P. Bennett

The MACHO collaboration reports on the analysis of our first year LMC data, 9.5 million light curves with an average of 235 observations each. Automated selection procedures give 3 events consistent with microlensing. We evaluate our experimental detection efficiency using a range of Monte- Carlo simulations. Using a `standard' halo density profile we find t

M. Boettcher, R. Schlickeiser

The contribution of the pair annihilation process in relativistic electron-positron jets to the gamma-ray emission of blazars is calculated. Under the same assumptions as for the calculation of the yield of inverse Compton scattered accretion disk radiation (Dermer and Schlickeiser 1993) we calculate the emerging pair annihilation radiation taking into accou

V. S. Dhillon, R. G. M. Rutten

We present spectropolarimetric observations of the eclipsing nova-like variable V1315 Aql, obtained with the aim of determining whether the single-peaked uneclipsed lines observed in this and related nova-likes are the result of disc emission scattered into the line of sight by the wind. The data show linear polarization with a mean value of 0.11+-0.02%. The

Paola Mazzei, Anna, Curir, Carlotta Bonoli

Ring galaxies are commonly known as objects where a burst of star formation was triggered by a close encounter with an intruder, maybe a satellite galaxy. BVRI CCD observations of five ring galaxies have been performed. Here we present the results of a self-consistent approach to reproduce their observed morphology and spectral energy distribution using upda

Frédéric Mangolte

For a real algebraic K3 surface $X(R)$, we give all possible values of the dimension $h^1_{alg}(X(R)$ of the group $\H^1_{alg}(X(R),Z/2)$ of algebraic cycles of $X(R)$. In particular, we prove that if $X(R)$ is not an M-surface, $X(R)$ can always be deformed to some $X'(R)$ with $h^1_{alg}(X'(R))=\dim\H^1(X(R),Z/2)$. Furthermore, we obtain that in ce

R. A. Sharipov, E. N. Tzyganov

A new generalization of the classical separate algebraicity theorem is suggested and proved.

Douglas Eardley, Gary Horowitz, David Kastor, Jennie Traschen

It is shown that topologically stable cosmic strings can, in fact, appear to end or to break, even in theories without monopoles. This can occur whenever the spatial topology of the universe is nontrivial. For the case of Abelian-Higgs strings, we describe the gauge and scalar field configurations necessary for a string to end on a black hole. We give a lowe

A. B. Zamolodchikov, Al. B. Zamolodchikov

An analytic expression is proposed for the three-point function of the exponential fields in the Liouville field theory on a sphere. In the classical limit it coincides with what the classical Liouville theory predicts. Using this function as the structure constant of the operator algebra we construct the four-point function of the exponential fields and ver

K. Patel, C. D. Wilson

Halpha and UBV photometry of NGC 6822 are used to study the distribution of OB stars and HII regions in the galaxy and to determine whether individual regions of the galaxy are in a state of ionization balance. Four distinct components of the Halpha emission (bright, halo, diffuse and field) differentiated by their surface brightnesses are identified. We fin

K. Patel, C. D. Wilson

Halpha and UBV photometry of the inner kpc of M33 are used to study the distribution of OB stars and HII regions in the galaxy and to determine whether individual regions of the galaxy are in a state of ionization balance. Based on the surface brightness of the Halpha emission, we identify three distinct ionized gas environments (bright, halo and field). We

J"urgen Fuchs, Bert Schellekens, Christoph Schweigert

Any automorphism of the Dynkin diagram of a symmetrizable Kac-Moody algebra induces an automorphism of the algebra and a mapping between its highest weight modules. For a large class of such Dynkin diagram automorphisms, we can describe various aspects of these maps in terms of another Kac-Moody algebra, the `orbit Lie algebra'. In particular, the generating

G. Boyd, J. Engels, F. Karsch, E. Laermann

Through a detailed investigation of the $SU(3)$ gauge theory at finite temperature on lattices of various size we can control finite lattice cut-off effects in bulk thermodynamic quantities. We calculate the pressure and energy density of the $SU(3)$ gauge theory on lattices with temporal extent $N_τ= 4$, 6 and 8 and spatial extent $N_σ=16$ and 32. The resul

Hyun-Chul Kim, Mikhail Shmatikov

The existence of flavor exotic $QQ\bar{q}\bar{q}$ molecular-type states is investigated. An attractive force between two {\it pseudoscalar} $H = (Q\bar{q})$ heavy meson is generated by (correlated) two-pion exchange. The emergence of a (loosely) bound state depends crucially on the value of the coupling constant $g$ of the $H^*Hπ$ vertex. For a $g$ value cal

W. Drechsler, Philip A. Tuckey

We study the Hilbert bundle description of stochastic quantum mechanics in curved spacetime developed by Prugovečki, which gives a powerful new framework for exploring the quantum mechanical propagation of states in curved spacetime. We concentrate on the quantum transport law in the bundle, specifically on the information which can be obtained from the flat

R. S. Bhalerao

A phenomenological model for the nucleon structure functions is presented. Visualising the nucleon as a cavity filled with parton gas in thermal equilibrium and parametrizing the effects due to the finiteness of the nucleon volume, we obtain a good fit to the data on the unpolarized nucleon structure functions.

I. Simonsen

In this review article we study the Minimal Supersymmetric Electro-Weak theory (of leptons). The Lagrangian is constructed step by step in great detail, both in the superfield and component field formalism --- both on and off shell. Furthermore the Lagrangian is written in the more familiar four component formalism. Electro weak symmetry breaking is discusse

R. Sasik, D. Stroud

We present the first non-mean-field calculation of the magnetization $M(T)$ of YBa$_2$Cu$_3$O$_{7-δ}$ both above and below the flux-lattice melting temperature $T_m(H)$. The results are in good agreement with experiment as a function of transverse applied field $H$. The effects of fluctuations in both order parameter $ψ({\bf r})$ and magnetic induction $B$ a

Francois Gygi, Giulia Galli

We present a real-space adaptive-coordinate method, which combines the advantages of the finite-difference approach with the accuracy and flexibility of the adaptive coordinate method. The discretized Kohn-Sham equations are written in generalized curvilinear coordinates and solved self-consistently by means of an iterative approach. The Poisson equation is

Gregery T. Buzzard, John Erik Fornaess

Let $H$ denote a composition of complex Hénon maps in {\bf C}$^2$. In this paper we show that the only possible compositional roots of $H$ are also compositions of Hénon maps, and that $H$ can have compositional roots of only finitely many distinct orders.

Gregery T. Buzzard, John Erik Fornaess

Let $X$ be a closed, $1$-dimensional, complex subvariety of $\CC^2$ and let $\ol{\BB}$ be a closed ball in $\CC^2 - X$. Then there exists a Fatou-Bieberbach domain $Ω$ with $X \subseteq Ω\subseteq \CC^2 - \ol{\BB}$ and a biholomorphic map $Φ: Ω\ra \CC^2$ such that $\CC^2 - Φ(X)$ is Kobayashi hyperbolic. As corollaries, there is an embedding of the plane in $

J. L. F. Barbon

Electric-magnetic duality and higher dimensional analogues are obtained as symmetries in generalized coset constructions, similar to the axial-vector duality of two dimensional coset models described by Rocek and Verlinde. We also study global aspects of duality between p-forms and (d-p-2)-forms in d-manifolds. In particular, the modular duality anomaly is g

Francesco Toppan

Constrained KP and super-KP hierarchies of integrable equations (generalized NLS hierarchies) are systematically produced through a Lie algebraic AKS-matrix framework associated to the homogeneous grading. The role played by different regular elements to define the corresponding hierarchies is analyzed as well as the symmetry properties under the Weyl group

A. Subbotin, I. V. Tyutin

We discuss the equivalence of two dual scalar field theories in 2 dimensions. The models are derived though the elimination of different fields in the same Freedman--Townsend model. It is shown that tree $S$-matrices of these models do not coincide. The 2-loop counterterms are calculated. It turns out that while one of these models is single-charged, the oth

G. W. Gibbons, P. K. Townsend

We show that the exact static, i.e. `anti-gravitating', magnetic multi monopole solutions of the Einstein/Maxwell/dilaton-YM/Higgs equations found by Kastor, London, Traschen, and the authors, for arbitrary non-zero dilaton coupling constant $a$, are equivalent to the string theory BPS magnetic monopole solutions of Harvey and Liu when $a=\sqrt{3}$. For

L. Martina, O. K. Pashaev, G. Soliani

We show that the classical non-abelian pure Chern-Simons action is related to nonrelativistic models in (2+1)-dimensions, via reductions of the gauge connection in Hermitian symmetric spaces. In such models the matter fields are coupled to gauge Chern-Simons fields, which are associated with the isotropy subgroup of the considered symmetric space. Moreover,

P D Jarvis, I Tsohantjis

A covariant scalar representation of $iosp(d,2/2)$ is constructed and analysed in comparison with existing methods for the quantization of the scalar relativistic particle. It is found that, with appropriately defined wavefunctions, this $iosp(d,2/2)$ produced representation can be identified with the state space arising from the canonical BFV-BRST quantizat

Wai-Keung Tang, M. Vänttinen

We study contributions from color-octet quarkonium formation mechanisms to $p_\perp$-integrated $ψ'$ production cross sections in pion-nucleon reactions. The observed polarization of the $ψ'$ is not reproduced by the lowest-order leading-twist color-singlet and color-octet mechanisms. This suggests that there are important quarkonium production mecha

Yu-Qi Chen, Robert J. Oakes

The hyperfine spin splittings in heavy quarkonia are studied using the recently developed renormalization group improved spin-spin potential which is independent of the scale parameter $μ$. The calculated energy difference between the $J/ψ$ and the $η_c$ fits the experimental data well, while the predicted energy difference $ΔM_p$ between the center of the g

R. C. Verma

We investigate nonfactorizable contributions to charm meson decays in $ D \rightarrow \bar K π$/ $ \bar K ρ$ /$ \bar K ^{*} π$ / $ \bar K a_{1}$ / $ \bar K ^{*} ρ$ modes. Obtaining the contributions from spectator-quark diagrams for $ N_{c}$ = 3, we determine nonfactorizable isospin 1/2 and 3/2 amplitudes required to explain the data for these modes. We obse

P. Mergell, Ulf-G. Meißner, D. Drechsel

Dispersion relations allow for a coherent description of the nucleon electromagnetic form factors measured over a large range of momentum transfer, $Q^2 \simeq 0 \ldots 35$ GeV$^2$. Including constraints from unitarity and perturbative QCD, we present a novel parametrisation of the absorptive parts of the various isoscalar and isovector nucleon form factors.

A. Ali, C. Greub

A comparison of the inclusive photon energy spectrum in the radiative decay $\BGAMAXS$, measured recently by the CLEO collaboration, with the standard model is presented, using a $B$-meson wave function model and improving earlier perturbative QCD-based computations of the same. The dependence of the photon energy spectrum on the non-perturbative model param

J. R. Forshaw

I discuss the theoretical status of the `soft' pomeron and its place in describing generic diffractive processes. The role of perturbative QCD (pQCD) corrections is considered, in particular in the context of quasi-elastic vector meson production at high $Q^2$. In those processes where short distances are dominant, the `hard' (pQCD) pomeron is expect

P. V. Vorobyov, A. N. Kirpotin, M. E. Rovkin, A. P. Boldyrev

The (pseudo) Goldstone bosons arise naturally in many modern theories such as supergravity, superstring theory and variants of general relativity with torsion. By the other hand, there are well known indications that a large part of the Universe mass exists in a form of dark matter. The most attractive model of the dark matter is non-relativistic gas of the

A. A. Penin, A. A. Pivovarov

Within quantum mechanics model we study the problem of resummation of an asymptotic perturbation series for bound state parameters via optimization of the perturbative expansion. A possible application of the method to the positronium lifetime calculation is also briefly considered.

S. Kumano, M. Miyama

Nuclear shadowing in the structure function $F_3$ is investigated as a possible test of shadowing models. The $F_3$ shadowing is studied in two different theoretical models: a parton-recombination model with $Q^2$ rescaling and an aligned-jet model. We find that predictions in these models differ completely in the small $x$ region. It suggests that the $F_3$

H. Suganuma, H. Ichie, S. Sasaki, H. Toki

Nonperturbative QCD is studied with the dual Ginzburg-Landau theory, where color confinement is realized through the dual Higgs mechanism by QCD-monopole condensation. We obtain a general analytic formula for the string tension. A compact formula is derived for the screened inter-quark potential in the presence of light dynamical quarks. The QCD phase transi

H. Toki, S. Sasaki, H. Suganuma

We study the properties of quarks, being confined in hadrons, with the Schwinger-Dyson equation in the dual Ginzburg-Landau Theory. Magnetic monopole condensation, which provides quark confinement, is demonstrated responsible also for dynamical chiral-symmetry breaking. We discuss then the recovery of the chiral symmetry at finite temperature.

Valdir B. Bezerra, Patricio S. Letelier

Loop variables are used to describe the presence of topological defects in spacetime. In particular we study the dependence of the holonomy transformation on angular momentum and torsion for a multi-chiral cone. We also compute the holonomies for multiple moving crossed cosmic strings and two plane topological defects-crossed by a cosmic string.

Guillermo A. Mena Marugan

Some aspects of the algebraic quantization programme proposed by Ashtekar are revisited in this article. It is proved that, for systems with first-class constraints, the involution introduced on the algebra of quantum operators via reality conditions can never be projected unambiguously to the algebra of physical observables, ie, of quantum observables modul

L. A. N. Amaral, A. -L. Barabasi, H. A. Makse, H. E. Stanley

We perform a systematic study of several models that have been proposed for the purpose of understanding the motion of driven interfaces in disordered media. We identify two distinct universality classes: (i) One of these, referred to as directed percolation depinning (DPD), can be described by a Langevin equation similar to the Kardar-Parisi-Zhang equation,

Matteo Beccaria

We consider the $U_q[SU(2)]$ symmetric Heisenberg chain when $q=e^{iπ/(m+1)}$ and $m$ is integer. We consider the cases $m=3$ and $m=5$ which correspond to the Ising and 3-state Potts models. We study the finite size scaling (FSS) of the ground states in different quantum spin sectors and restricting to highest weights of type-II representations. We compute

A. J. Millis, H. Monien

We present and solve a model for the susceptibility of two CuO2 planes coupled by an interplane coupling J_perp and use the results to analyze a recent "cross-relaxation" NMR experiment on Y2Ba4Cu7O15. We deduce that in this material the product of J_perp and the maximum value of the in-plane susceptibility chi_max varies from approximately 0.2 at T

Hiroaki Nakamura, Naomichi Hatano, Minoru Takahashi

The finite-size scaling function of the nonlinear susceptibility of the ferromagnetic Heisenberg chain is given explicitly. It is conjectured that the scaling function is universal for any values of $S$. The conjecture is based on the exact solution of the nonlinear susceptibility for $S=\infty$, and numerical calculations for $S=1/2$ and $S=1$.

P. Tini Brunozzi, S. Borgani, M. Plionis, L. Moscardini

We study the dipole for a redshift sample of Abell/ACO clusters. To elucidate the constraints it places on dark matter models, we use numerical simulations based on the Zel'dovich approximation. We run 20 realizations of each of six different dark matter models: four of these have a density parameter $Ω_0=1$, while the other two have $Ω_0=0.2$, one with

R. F. Peletier, E. A. Valentijn, A. F. M. Moorwood, W. Freudling

To investigate the distribution of dust in Sb and Sc galaxies we have analyzed near-infrared and optical surface photometry for an unbiased sample of 37 galaxies. Since light in the $K$-band is very little affected by extinction by dust, the $B-K$ colour is a good indicator of the amount of extinction, and using the colour-inclination relation we can statist

Basilio X. Santiago, Gerard Gilmore, Rebecca A. W. Elson

We use star counts from 13 deep HST fields imaged with the {\it Wide Field Camera - 2} in order to constrain the amount of dark matter in the Galaxy that can be in the form of low-mass main sequence stars or white-dwarfs. Based on the number of red stars found in our fields, we exclude the possibility that more than 25\% of the massive dark halo is made up o

C. D. Wilson, B. C. Matthews

$UBV$ photometry is used to re-identify the OB associations which power the two most luminous HII regions in M33, NGC 604 and NGC 595. There is a significant difference (2-3 Myr) in the ages of the most recent star formation episode in these two regions, while NGC 595 also has undergone a prior episode of star formation (10-15 Myr ago). These data, combined

C. D. Wilson

High-resolution CO maps of 9 molecular clouds in IC 10 are combined with the new measurement of the distance to this nearby metal poor galaxy to measure accurately the CO-to-H2 conversion factor. The result for IC 10 is combined with published data for four other Local Group galaxies (M31, M33, NGC 6822, the SMC) to trace the dependence of the CO-to-H2 conve

J. M. Liu, J. G. Gao

We investigate the effect of gravitational lensing, produced by linear density perturbations, for anisotropies of the Cosmic Background Radiation (CBR) on scales of arcminutes. In calculations, a flat universe ($Ω=1$) and the Harrison-Zel'dovich spectrum ($n=1$) are assumed. The numerical results show that on scales of a few arcminutes, gravitational len

C. Alard, S. Mao, J. Guibert

We present the light curve of an unusual variable object, DUO 2, detected during the search for microlensing events by the DUO project. The star remained stable for more than 150 days before it brightened by more than two magnitudes in 6 days in the B and R bands. The light curves are achromatic during the variability. We consider possible explanations of th

James G. Bartlett, Alain Blanchard

We discuss the development and physics of the cosmic virial theorem and its traditional application as an indicator of the cosmic mean density. The standard result that the density must be sub-critical relies on the assumption that the galaxy three-point correlation function accurately describes the mass distribution around a typical pair of galaxies. To cha

Mordehai Milgrom, Vladimir Usov

The little we do know of the physical conditions in gamma-ray bursters makes them conducive to the acceleration of high-energy cosmic rays, especially if they are at cosmological distances. We find that, with the observed statistics and fluxes of gamma-ray bursts, cosmological bursters may be an important source of cosmic rays in two regions of the observed

Steven B. Bradlow, Oscar Garcia-Prada

We introduce equations for special metrics, and notions of stability for some new types of augmented holomorphic bundles. These new examples include holomorphic extensions, and in this case we prove a Hitchin-Kobayashi correspondence between a certain deformation of the Hermitian-Einstein equations and our definition of stability for an extension.

G. K. Sankaran

Take a bounded symmetric domain $D$ and an arithmetic subgroup $Γ$ of ${\rm Aut}(D)$. Take the quotient $D/Γ$, compactify and resolve the singularities. We study the fundamental group of the compact complex manifolds that result from this procedure, and in particular the case of Siegel modular threefolds.

M. J. Duff, James T. Liu, R. Minasian

Membrane/fivebrane duality in D=11 implies Type IIA string/Type IIA fivebrane duality in D=10, which in turn implies Type IIA string/heterotic string duality in D=6. To test the conjecture, we reproduce the corrections to the 3-form field equations of the D=10 Type IIA string (a mixture of tree-level and one-loop effects) starting from the Chern-Simons corre

P. Singha Deo

It was shown using perturbation theory[1] that Thouless energy Ec for a quantum system scales linearly with the conductance of the system. We derive in an alternate way in 1-D that Ec scales with the conductance in a very different way. We physically show the difference between our approach and that of ref. 1 to expect our results to hold in higher dimension

G. Amelino-Camelia, D. Seminara

In the semiclassical analysis of black hole radiation in matter-coupled dilaton gravity, a one-parameter ``$k$"-family of measures for the path integral quantization of the matter fields is considered. The Weyl anomaly is proportional to the parameter $k$, but the black hole radiation seen by minkowskian observers at future null infinity is $k$-independe

D. E. Post

The most promising concepts for power and particle control in tokamaks and other fusion experiments rely upon atomic processes to transfer the power and momentum from the edge plasma to the plasma chamber walls. This places a new emphasis on processes at low temperatures (1-200 eV) and high densities (10^20-10^22 m^-3). The most important atomic processes ar

D. Post, N. Putvinskaya, F. W. Perkins, W. Nevins

Present divertor concepts for next step experiments such ITER and TPX rely upon impurity and hydrogen radiation to transfer the energy from the edge plasma to the main chamber and divertor chamber walls. The efficiency of these processes depends strongly on the heat flux, the impurity species, and the connection length. Using a database for impurity radiatio

R. Clark, J. Abdallah, D. Post

The role of impurity radiation in the reduction of heat loads on divertor plates in present experiments such as DIII-D, JET, JT-60, ASDEX, and Alcator C-Mod, and in planned experiments such as ITER and TPX places a new degree of importance on the accuracy of impurity radiation emission rates for electron temperatures below 250 eV for ITER and below 150 eV fo

Christof Schmidhuber

The renormalization group flow in two-dimensional field theories that are coupled to gravity has unusual features: First, the flow equations are second order in derivatives. Second, in the presence of handles the flow has quantum mechanical properties. Third, the beta functions contain the elementary higher-genus vertices of closed string field theory. This

C. E. Vayonakis

String-loop effects may generate very weak matter couplings for a (massless) dilaton. We examine limits on the shift of such a dilaton toward its present equilibrium value from big-bang nucleosynthesis and the binary pulsar. On the other hand, the approach of the dilaton toward its present value can be realized in the early universe in a quick and efficient

Morton E. Gurtin, Debra Polignone, Jorge Vinals

A unified framework for coupled Navier-Stokes/Cahn-Hilliard equations is developed using, as a basis, a balance law for microforces in conjunction with constitutive equations consistent with a mechanical version of the second law. As a numerical application of the theory, we consider the kinetics of coarsening for a binary fluid in two space-dimensions.

C. Destri, T. Segalini

The light--cone lattice approach to the massive Thirring model is reformulated using a local and integrable lattice Hamiltonian written in terms of discrete fermi fields. Several subtle points concerning boundary conditions, normal--ordering, continuum limit, finite renormalizations and decoupling of fermion doublers are elucidated. The relations connecting

V. A. Slobodenyuk

The Schwinger--DeWitt expansion for the evolution operator kernel is used to investigate analytical properties of the Schrödinger equation solution in time variable. It is shown, that this expansion, which is in general asymptotic, converges for a number of potentials (widely used, in particular, in one-dimensional many-body problems), and besides, the conve

C. Anastopoulos

We consider the decoherence of phase space histories in a class of quantum Brownian motion models, consisting of a particle moving in a potential $V(x)$ in interaction with a heat bath at temperature $T$ and dissipation gamma, in the Markovian regime. The evolution of the density operator for this open system is thus described by a non-unitary master equatio

M. Alves

We introduce an external field to calculate the quantum corrections of the 2d gravity, via trace anomaly. We show that there are black hole type solution even in the absence of matter field and cosmological constant. We also see that these solutions are similar to the ones obtained from dilaton two-dimensional gravity.

Enrique Alvarez, J. M. Gracia-Bondía, C. P. Martín

It is well known that anomaly cancellation {\it almost} determines the hypercharges in the standard model. A related (and somewhat more stronger) phenomenon takes place in Connes' NCG framework: unimodularity (a technical condition on elements of the algebra) is {\it strictly} equivalent to anomaly cancellation (in the absence of right-handed neutrinos);

Frank Göhmann, Miki Wadati

The su(1$|$1) symmetric version of the Haldane-Shastry spin chain is diagonalized by means of a linear transformation. The same transformation applied to the original su(2) model yields simple expressions for the Hamiltonian and the generators of the Yangian symmetry of the model in terms of spin wave operators.

Eric Chisolm, E. C. G. Sudarshan, Thomas F. Jordan

Griffiths' ``quantum trajectories'' formalism is extended to describe weak decoherence. The decoherence conditions are shown to severely limit the complexity of histories composed of fine-grained events.

Lior Goldenberg, Lev Vaidman

New applications of the formula $A |ψ\rangle = \langle A \rangle |ψ\rangle + ΔA |ψ_{\perp} \rangle$ are discussed. Simple derivations of the Heisenberg uncertainty principle and of related inequalities are presented. In addition, the formula is used in an instructive paradox which clarifies a fundamental notion in quantum mechanics.

D. Post, J. Abdallah, R. E. H. Clark, N. Putvinskaya

Reduction of the peak heat loads on the plasma facing components is essential for the success of the next generation of high fusion power tokamaks such as the International Thermonuclear Experimental Reactor (ITER) 1 . Many present concepts for accomplishing this involve the use of atomic processes to transfer the heat from the plasma to the main chamber and

F. Arias de Saavedra, G. Co', A. Fabrocini, S. Fantoni

The Correlated Basis Function theory (CBF) provides a theoretical framework to treat on the same ground mean-field and short-range correlations. We present, in this report, some recent results obtained using the CBF to describe the ground state properties of finite nuclear systems. Furthermore we show some results for the excited state obtained with a simpli

G. Amelino-Camelia, D. Bak, D. Seminara

We derive anomalous Ward identities in two different approaches to the quantization of massless matter-gravity fields in 1+1 dimensions.

Oren Bergman, Charles B. Thorn

We extend the model of string as a polymer of string bits to the case of superstring. We mainly concentrate on type II-B superstring, with some discussion of the obstacles presented by not II-B superstring, together with possible strategies for surmounting them. As with previous work on bosonic string we work within the light-cone gauge. The bit model posses

L. Bonora, F. Nesti, E. Vinteler

We analyze multi--matrix chain models. They can be considered as multi--component Toda lattice hierarchies subject to suitable coupling conditions. The extension of such models to include extra discrete states requires a weak form of integrability. The discrete states of the $q$--matrix model are organized in representations of $sl_q$. We solve exactly the G

St. Thurner, H. Markum, W. Sakuler

We analyze topological objects in pure QCD in the presence of external quarks by calculating the distributions of instanton and monopole densities around static color sources. We find a suppression of the densities close to external sources and the formation of a flux tube between a static quark--antiquark pair. The similarity in the behavior of instantons a

Debashis Ghoshal, Cumrun Vafa

We show that the non-critical $c=1$ string at the self-dual radius is equivalent to topological strings based on the deformation of the conifold singularity of Calabi-Yau threefolds. The Penner sum giving the genus expansion of the free energy of the $c=1$ string theory at the self-dual radius therefore gives the universal behaviour of the topological partit

R. Brout, S. Massar, R. Parentani, Ph. Spindel

In a recent work, Unruh showed that Hawking radiation is unaffected by a truncation of free field theory at the Planck scale. His analysis was performed numerically and based on a hydrodynamical model. In this work, by analytical methods, the mathematical and physical origin of Unruh's result is revealed. An alternative truncation scheme which may be mor

Uwe Grimm, S. Ole Warnaar

We present a Baxterization of a two-colour generalization of the Birman--Wenzl--Murakami (BWM) algebra. Appropriately combining two RSOS-type representations of the ordinary BWM algebra, we construct representations of the two-colour algebra. Using the Baxterization, this provides new RSOS-type solutions to the Yang--Baxter equation.

S. D. Odintsov, A. Wipf

We discuss the renormalization group improved effective action and running surface couplings in curved spacetime with boundary. Using scalar self-interacting theory as an example, we study the influence of the boundary effects to effective equations of motion in spherical cap and the relevance of surface running couplings to quantum cosmology and symmetry br

A. C. Petkou

Using Operator Product Expansions and a graphical ansatz for the four-point function of the fundamental field ϕ^α(x) in the conformally invariant O(N) vector model, we calculate the next-to-leading order in 1/N values of the quantities C_{T} and C_{J}. We check the results against what is expected from possible generalisations of the C- and k-theorems in hig

Kazuhiko Odaka

From the point of view of topology we study the induced representation technique which E. Wigner proposed in 1939. We comment on the gauge structure in the induced representation technique and construc the explicit form of the gauge fields. The topological results ofour study are applied to quantum mechanics on a d-dimensional sphere and its path integral is

Renata Kallosh

A general covariant quantization of superparticle, Green-Schwarz superstring and a supermembrane with manifest supersymmetry and duality symmetry is proposed. This quantization provides a natural quantum mechanical description of curved BPS-type backgrounds related to the ultra-short supersymmetry multiplets. Half-size commuting and anticommuting Killing spi

Jonathan L. Rosner

This series of five lectures describes aspects of CP violation, emphasizing its description within the standard electroweak model. After discussing the kaon system, the only place in which CP violation has been seen so far, we turn to the leading contender for the effect, complex phases in the Cabibbo-Kobayashi-Maskawa (CKM) matrix. A number of suggestions a

C. E. Vayonakis

The ralaxation mechanism of Damour-Polyakov for fixing the vacuum expectation value of certain scalar fields (moduli) in string theory could provide a convenient framework for the Peccei-Quinn relaxation mechanism and remove the narrow "axion window".

F. De Paolis, G. Ingrosso, Ph. Jetzer, M. Roncadelli

Recent observations of microlensing events in the Large Magellanic Cloud by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in form of Massive Astrophysical Compact Halo Objects (MACHOs) with mass ~ 0.1 M_{\odot}. We outline a scenario in which dark clusters of MACHOs and molecular clouds form in the halo at galac

Konstantin Goulianos

The results of experiments at hadron colliders probing the structure of the pomeron through hard diffraction are reviewed. Some results on deep inelastic diffractive scattering obtained at HERA are also discussed and placed in perspective. By using a properly normalized pomeron flux factor in single diffraction dissociation, as dictated by unitarity, the pom

S. A. Abel, S. Sarkar, P. L. White

We study the cosmology of the Supersymmetric Standard Model augmented by a gauge singlet to solve the $μ$-problem and describe the evolution of the domain walls which are created during electroweak symmetry breaking due to the discrete $Z_{3}$ symmetry in this model. The usual assumption, that non-renormalizable terms induced by gravity (which explicitly bre

H. F. Jones, I. S. Solovtsov, O. P. Solovtsova

A non-perturbative expansion method which gives a well-defined analytic continuation of the running coupling constant from the spacelike to the timelike region is applied to the inclusive semileptonic decay of the $τ$--lepton. The method allows us to evaluate $R_τ$ by integration over the non-perturbative physical region, rather than by using Cauchy's th

Stefano Catani

I present some comments on the partonic interpretation of the HERA data on the proton structure function. The effects of the resummation of the leading and next-to-leading $\ln x$-contributions are discussed. A new factorization scheme, in which these resummation effects are absorbed into a steep redefinition of the gluon density, is introduced and its (poss

Elizabeth Jenkins, Aneesh V. Manohar, Mark B. Wise

The interactions of $ρ$, $K^*$, $ϕ$ and $ω$ vector-mesons with low-momentum $π$, $K$ and $η$ pseudoscalar mesons are constrained by chiral symmetry. We derive a heavy vector-meson chiral Lagrangian in which the vector mesons are treated as heavy static matter fields. The unknown couplings of the chiral Lagrangian are further related using the $1/N_c$ expansi

Z. K. Silagadze

A new, "quantum mechanical" algorithm is proposed for automatic photopeak location in gamma-ray spectra from semiconductor and scintillator detectors.

H1 Collaboration

The production of transverse energy in deep inelastic scattering is measured as a function of the kinematic variables $x$ and $Q^2$ using the H1 detector at the ep collider HERA. The results are compared to the different predictions based upon two alternative QCD evolution equations, namely the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and the Balit

J. I. Fleck

In the following article we describe our measurement of the proton structure function $F_2$ and of the gluon momentum density $xg$ in $ep$ collisions with the ZEUS detector at HERA in 1993. The results for $F_2$ confirm our measurement from the previous year but with much higher statistics and show a strong rise towards small $x$. The gluon momentum density

R. Jackiw

Commutator anomalies obstruct solving the Wheeler-DeWitt constraint equation in Dirac quantization of quantum gravity-matter theory. When the obstruction is removed, there result quantal modifications to the constraints. The same classical theory gives rise to different quantum theories when different procedures for overcoming anomalies are implemented.

Patricio S. Letelier

Spacetimes with everywhere vanishing curvature tensor, but with torsion different from zero only on world sheets that represent closed loops in ordinary space are presented, also defects along open curves with end points at infinity are studied. The case of defects along timelike loops is also considered and the geodesics in these spaces are briefly discusse

W. M. Seiler, R. W. Tucker

We study some two-dimensional dilaton gravity models using the formal theory of partial differential equations. This allows us to prove that the reduced phase space is two-dimensional without an explicit construction. By using a convenient (static) gauge we reduce the theory to coupled \ode s and we are able to derive for some potentials of interest closed-f