July 1995 arXiv papers — page 9

Chris Quigg

I compare the anticipated properties of the top quark with what is known experimentally about the heaviest fermion. I review the scientific opportunities that will be presented in the near future by copious samples of top. These include refined tests of electroweak radiative corrections, studies of the nature of top itself, and exploration of electroweak sym

Chr. V. Christov, A. Z. Górski, K. Goeke, P. V. Pobylitsa

In this paper we present the derivation as well as the numerical results for the electromagnetic form factors of the nucleon within the chiral quark soliton model in the semiclassical quantization scheme. The model is based on semibosonized SU(2) Nambu -- Jona-Lasinio lagrangean, where the boson fields are treated as classical ones. Other observables, namely

A. H. Hoang, J. H. Kühn, T. Teubner

Secondary radiation of hadrons from a tau pair produced in electron positron collisions may constitute an important obstacle for precision measurements of the production cross section and of branching ratios. The rate for real and virtual radiation is calculated and various distributions are presented. For Z decays a comprehensive analysis is performed which

D. V. Antonov, Yu. A. Simonov

Stochastic quantization is used to derive exact equations, connecting multilocal field correlators in the phi^3 theory and gluodynamics. Perturbative expansion of the obtained equations in the lowest orders is presented.

Anton Kapustin, Zoltan Ligeti, H. David Politzer

Part of the order $α_s$ correction to the inclusive $B\to X_s\,γ$ photon spectrum is enhanced by $\log(m_b^2/m_s^2)$. We discuss its origin and sum the corrections proportional to $[α_s\log(m_b^2/μ^2)]^n$ to all orders. These are the calculable leading logarithms in the parton fragmentation functions of a quark or gluon into a photon. Although the gluon frag

Kang Young Lee, Jae Kwan Kim

We study the approximate flavour symmetries imposed on the lepton sector assuming see-saw mechanism as the neutrino mass structure. We apply the symmetry to various neutrino phenomenologies and obtain constraints on neutrino masses and mixings.

Wolfhard Janke, Ramon Villanova

We use two-dimensional Poissonian random lattices of Voronoi/ Delaunay type to study the effect of quenched coordination number randomness on the nature of the phase transition in the eight-state Potts model, which is of first order on regular lattices. From extensive Monte Carlo simulations we obtain strong evidence that the phase transition remains first o

Martin Hasenbusch

I provide evidence that the 2D $RP^{N-1}$ model for $N \ge 3$ is equivalent to the $O(N)$-invariant non-linear $σ$-model in the continuum limit. To this end, I mainly study particular versions of the models, to be called constraint models. I prove that the constraint $RP^{N-1}$ and $O(N)$ models are equivalent for sufficiently weak coupling. Numerical result

Dieter R. Brill

CONTENTS: 1 Introduction 2 Analytic Manifolds and Analytic Continuation of Metrics 3 Walker's Spacetimes and their Maximal Extension 4 Global Structure of de Sitter and Reissner-Nordström-de Sitter Cosmos 4.1 Special Cases 4.2 Collapsing Dust 5 Euclidean Metrics 6 Physical Interpretation of Euclidean Solutions, and a remark about the Gravitational Action

Toshiharu Kawai

In a teleparallel theory of (2+1)-dimensional gravity developed in a previous paper, we examine generators of internal Lorentz transformations and of general affine coordinate transformations for static circularly symmetric exact solutions of gravitational field equation. The \lq \lq spin" angular momentum, the energy-momentum and the \lq \lq extended or

M. R. Norman, M. Randeria, H. Ding, J. C. Campuzano

We discuss polarization selection rules for angle-resolved photoemission spectroscopy in Bi2212. Using these we show that the ``hump'' in the superconducting gap observed in the $X$ quadrant in our earlier work is not on the main $CuO_2$ band, but rather on an umklapp band arising from the structural superlattice. The intrinsic gap is most likely qui

H. Ding, A. F. Bellman, J. C. Campuzano, M. Randeria

From a detailed study, including polarization dependence, of the normal state angle-resolved photoemission spectra for Bi$_2$Sr$_2$CaCu$_2$O$_8$, we find only one CuO$_2$ band related feature. All other spectral features can be ascribed either to umklapps from the superlattice or to ``shadow bands''. Even though the dispersion of the peaks looks like

Mehran Kardar

Inhomogeneities in deposition may lead to formation of rough surfaces, whose height fluctuations can be probed directly by scanning microscopy, or indirectly by scattering. Analytical or numerical treatments of simple growth models suggest that, quite generally, the height fluctuations have a self-similar character. The roughness and dynamic exponents are ex

U. Pustogowa, W. Hubner, K. H. Bennemann

Using a spin-polarized full-potential linear muffin-tin orbital method we present calculations of the nonlinear magneto-optical Kerr effect for thin bcc Fe films within a slab geometry. Film layer dependent contributions to the Kerr spectrum are determined. Thus, we calculate the magneto-optical Kerr spectra for the linear and nonlinear case. Our results sho

Baowen Li, Marko Robnik

The boundary integral method (BIM) is a formulation of Helmholtz equation in the form of an integral equation suitable for numerical discretization to solve the quantum billiard. This paper is an extensive numerical survey of BIM in a variety of quantum billiards, integrable (circle, rectangle), KAM systems (Robnik billiard) and fully chaotic (ergodic, such

S. Ruffo, D. L. Shepelyansky

We study local diffusion rate $D$ in Chirikov standard map near the critical golden curve. Numerical simulations confirm the predicted exponent $α=5$ for the power law decay of $D$ as approaching the golden curve via principal resonances with period $q_n$ ($D \sim 1/q^α_n$). The universal self-similar structure of diffusion between principal resonances is de

David Crampton, J. B. Hutchings, A. P. Cowley, P. C. Schmidtke

A detailed analysis of simultaneous photometric and spectroscopic observations of the optical counterpart of the LMC "supersoft" X-ray source RX J0513.9-6951 (identified with HV 5682) is presented. The spectrum is dominated by He II emission lines and H + He II blends; no He I is observed but several higher ionization emission features, especially O

D. J. Schade, S. J. Lilly, David Crampton, F. Hammer

HST B and I images are presented of 32 CFRS galaxies with secure redshifts in the range 0.5 < z < 1.2. These galaxies exhibit the same range of morphological types as seen locally, i.e., ellipticals, spirals and irregulars. The galaxies look far less regular in the $B$ images (rest-frame ultraviolet) than at longer wavelengths, underlining the fact that opti

M. B. Davies

In studying encounters between binaries and single stars, one is interested in three classes of events: exchanges of stars, hardening of the original binary by a third star, and the production of merged objects. We present a means for computing cross sections for these three outcomes for an arbitrary binary and single star as might be found in the core of a

M. B. Davies, W. Benz

Using King-Mitchie Models, we compute encounter rates between the various stellar species in the globular clusters $ω$ Cen, and 47 Tuc. We also compute event rates for encounters between single stars and a population of primordial binaries. Using these rates, and what we have learnt from hydrodynamical simulations of encounters performed earlier, we compute

Rien van de Weygaert, Edmund Bertschinger

We develop an algorithm for setting up initial Gaussian random density and velocity fields containing one or more peaks or dips, in an arbitrary cosmological scenario. The intention is to generate appropriate initial conditions for cosmological N-body simulations that focus on the evolution of the progenitors of the present-day galaxies and clusters. The pro

Michael L&#34;onne

In this paper we determine for relatively minimal elliptic surfaces with positive Euler number the image of the natural representation of the group of orientation preserving self-diffeomorphisms on $\Hbar$, the second homology group reduced modulo torsion. To this end we construct as many embedded spheres of square -2 such that an isometry not induced from a

Jeroen G. Spandaw

In this note we use the monodromy argument to prove a Noether-Lefschetz theorem for vector bundles.

S. Orevkov, M. Zaidenberg

This is an extended, renovated and updated report on a joint work which the second named author presented at the Conference on Algebraic Geometry held at Saitama University, 15-17 of March, 1995. The main result is an inequality for the numerical type of singularities of a plane curve, which involves the degree of the curve, the multiplicities and the Milnor

H. Flenner, M. Zaidenberg

We obtain new examples and the complete list of the rational cuspidal plane curves $C$ with at least three cusps, one of which has multiplicity ${\rm deg}\,C - 2$. It occurs that these curves are projectively rigid. We also discuss the general problem of projective rigidity of rational cuspidal plane curves.

Wolfgang Bauer, Scott Pratt

We examine the line-wrap feature of text processors and show that adding characters to previously formatted lines leads to the cascading of words to subsequent lines and forms a state of self-organized criticality. We show the connection to one-dimensional random walks and diffusion problems, and we examine the predictability of catastrophic cascades.

Thibault Damour, David Vokrouhlicky

The perturbation of the lunar motion caused by a hypothetical violation of the equivalence principle is analytically worked out in terms of power series \`a la Hill-Brown. The interaction with the quadrupolar tide is found to amplify the leading order term in the synodic range oscillation by more than 62\%. Confirming a recent suggestion of Nordtvedt, we fin

O. Ganor, J. Sonnenschein

After adding auxiliary fields and integrating out the original variables, the Yang-Mills action can be expressed in terms of local gauge invariant variables. This method reproduces the known solution of the two dimensional $SU(N)$ theory. In more than two dimensions the action splits into a topological part and a part proportional to $α_s$. We demonstrate th

Chetan Nayak, Frank Wilczek

We analyze the phase transition between spin-singlet and spin-polarized states which occurs at $ν=2/3$. The basic strategy is to use adiabatic flux-trading arguments to relate this transition to the analogous transition at $ν=2$. The transition is found to be similar to a transition in ferromagnets. In our analysis, we find two possible scenarios. In one, th

Maxim Nazarov, Grigori Olshanski

We study analogues of the Yangian of the Lie algebra $gl_N$ for the other classical Lie algebras $so_N$ and $sp_N$. We call them twisted Yangians. They are coideal subalgebras in the Yangian $Y(gl_N)$ of $gl_N$ and admit homomorphisms onto the universal enveloping algebras $U(so_N)$ and $U(sp_N)$ respectively. In every twisted Yangian we construct a family o

A. Gonzalez Arroyo, P. Martinez, A. Montero

By looking at cooled configurations on the lattice, we study the presence of peaks in the action density, or its electric and magnetic components, in the SU(2) gauge vacuum. The peaks are seen to be of instanton-like nature and their number variation takes care of the drop in the string tension observed when cooling. Possible explanations of this finding are

A. Capella, A. Kaidalov, A. Kouider Akil, C. Merino

The rapidity distribution of $Λ$ and $\barΛ$ produced in nucleus-nucleus collisions at CERN energies is studied in the framework of an independent string model - with quark-antiquark as well as diquark-antidiquark pairs in the nucleon sea. It is shown that, besides the $Λ$-$\barΛ$ pair production resulting from the fragmentation of sea diquarks, final state

J. Gegelia, G. Japaridze, N. Kiknadze, K. Turashvili

Renormalization procedure is generalized to be applicable for non renormalizable theories. It is shown that introduction of an extra expansion parameter allows to get rid of divergences and express physical quantities as series of finite number of interdependent expansion parameters. Suggested method is applied to quantum (Einstein&#39;s) gravity.

A. J. S. Hamilton

Redshift space distortions on large scales can be used to measure the linear growth rate parameter $\ff \approx \Omega^{0.6}/b$. I report here measurements of such distortions in the IRAS 2 Jy, 1.2 Jy, and QDOT redshift surveys, finding $\ff = 0.69^{+ .21}_{- .19}$ from a merged QDOT plus 1.2 Jy catalogue. Unfortunately, confidence in this result is undermin

A. J. S. Hamilton, M. Culhane

Peculiar velocities induce apparent line of sight displacements of galaxies in redshift space, distorting the pattern of clustering in the radial versus transverse directions. On large scales, the amplitude of the distortion yields a measure of the dimensionless linear growth rate $β\approx Ω^{0.6}/b$, where $Ω$ is the cosmological density and $b$ the linear

F. Buccella, O. Pisanti, P. Santorelli, J. Soffer

The SLAC data on the p, d and n polarized structure functions are fairly well reproduced with and without the contribution of the anomaly. The results are compared with a previous study based mainly on SMC data. The implications on the solution of the spin-crisis are discussed.

Paul J. M. Bastiaansen, Hubert J. F. Knops

We study the phase diagram of the BCSOS model with an extended interaction range using transfer matrix techniques, pertaining to the (100) surface of single component fcc and bcc crystals. The model shows a 2x2 reconstructed phase and a disordered flat phase. The deconstruction transition between these phases merges with a Kosterlitz-Thouless line, showing a

R. J. Radtke, A. I. Liechtenstein, V. M. Yakovenko, S. Das Sarma

Spin-fluctuation-mediated superconductivity is conventionally associated with d_{x^2-y^2} pairing. We show that a generalized model of antiferromagnetic spin fluctuations in three dimensions may also yield a state with formal ``s-wave&#39;&#39; (A_{1g}) symmetry but with line nodes at k_z \approx \pm π/ 2c. We study this new state within both BCS and Eliashb

Gilad Lifschytz, Miguel E. Ortiz

Quantum fluctuations in the background geometry of a black hole are shown to affect the propagation of matter states falling into the black hole in a foliation that corresponds to observations purely outside the horizon. A state that starts as a Minkowski vacuum at past null infinity gets entangled with the gravity sector, so that close to the horizon it can

N. A. Saulina, M. V. Terentiev, K. N. Zyablyuk

The equations of motion (e.m.&#39;s) of the N=1, D=10 anomaly free supergravity, obtained in the framework of the superspace approach, are analyzed. The formal equivalence of the usual and dual supergravities is discussed at the level of e.m.&#39;s. The great simplicity of the dual formulation is established. The possibillity of the lagrangian formulation of

V. Quilis, J. M. Ibanez, D. Saez

Previous estimates of the microwave background anisotropies produced by freely falling spherical clusters are discussed. These estimates are based on the Swiss-Cheese and Tolman-Bondi models. It is proved that these models give only upper limits to the anisotropies produced by the observed galaxy clusters. By using spherically symmetric codes including press

Pavel Kroupa

We use N-body integration to follow the evolution of clusters of 200 binary systems with different initial half mass radii $R_{0.5}$. We also simulate single-star clusters. All clusters evolve according to the same $n(t)$ curve, where $n(t)$ is the number density of stars in the central 2~pc sphere at time $t$. $n(t)$ and the lifetime are independent of (i)

A. Vogt

The basic concepts and predictions of the `dynamical&#39; GRV parton distributions for hadrons and photons are discussed. Comparisons of these predictions with recent experimental results, especially from HERA, are presented.

Rathin Adhikari, Biswarup Mukhopadhyaya

In a supersymmetric model with the lightest supersymmetric particle (LSP) $χ$ in the range of a few hundred MeV&#39;s, the decay $τ{\longrightarrow} μχχ$ is going to be allowed. We investigate the departure from tau-universality caused by this decay. It is found that the universality violation in this way can be greater than both non-universal electroweak ra

J. Manjavidze

The aim of the article is to show how a coordinate transformation can be applied to the path-integral formalism. For this purpose the unitary definition of the quantum measure, which guarantees the conservation of total probability, is offered. As the examples, the phase space transformation to the canonically conjugate pare $(energy, time)$ and the transfor

Y. Georgelin, J. Madore, T. Masson, J. Mourad

A recently proposed definition of a linear connection in non-commutative geometry, based on a generalized permutation, is used to construct linear connections on GL_q(n). Restrictions on the generalized permutation arising from the stability of linear connections under involution are discussed. Candidates for generalized permutation on GL_q(n) are found. It

Wolfgang Bauer, Charles D. Mackenzie

We utilize the fractal dimension of the perimeter surface of cell sections as a new observable to characterize cells of different types. We propose that it is possible to distinguish cancerous from healthy cells with the aid of this new approach. As a first application we show that it is possible to perform this distinction between patients with hairy-cell l

K. Hagino, N. Takigawa

We discuss the effects of fast nuclear excitations on heavy-ion fusion reactions at energies near and below the Coulomb barrier. Using the fusion of two $^{40}$Ca nuclei as an example and the inversion method, we show that the mass renormalization induced by fast nuclear excitations leads to a large surface diffuseness in the effective potential for heavy-io

K. Hagino, N. Takigawa, A. B. Balantekin, J. R. Bennett

We use the two time influence functional method of the path integral approach in order to reduce the dimension of the coupled-channels equations for heavy-ion reactions based on the no-Coriolis approximation. Our method is superior to other methods in that it easily enables us to study the cases where the initial spin of the colliding particle is not zero. I

Koichi Saito, Anthony W. Thomas

There is a well known anomaly between the value of the Fermi decay constant extracted from super-allowed Fermi beta-decay of nuclear isotriplets and that required by unitarity of the Cabibbo-Kobayashi-Maskawa matrix. This discrepancy remains at the level of a few tenths of a percent after the most rigorous investigation of conventional nuclear and radiative

Bjorn Poonen

It is conjectured that for fixed $A$, $r \ge 1$, and $d \ge 1$, there is a uniform bound on the size of the torsion submodule of a Drinfeld $A$-module of rank $r$ over a degree $d$ extension $L$ of the fraction field $K$ of $A$. We verify the conjecture for $r=1$, and more generally for Drinfeld modules having potential good reduction at some prime above a s

Olivier de Mirleau

In this work we present a number of generalizations of Wick&#39;s theorems on integrals with Gaussian weight to a larger class of weights which we call subgaussian. Examples of subgaussian contractions are that of Kac-Moody or Virasoro type, although the concept of a subgaussian weight does not refer a priori to two-dimensional field theory. The generalizati

Sabbir Rahman, Barton Zwiebach

We complete the proof of the ghost-dilaton theorem in string theory by showing that the coupling constant dependence of the vacuum vertices appearing in the closed string action is given correctly by one-point functions of the ghost-dilaton. To prove this at genus one we develop the formalism required to evaluate off-shell amplitudes on tori.

Stefan Mashkevich, Jan Myrheim, Kåre Olaussen, Ronald Rietman

We develop the concept of trajectories in anyon spectra, i.e., the continuous dependence of energy levels on the kinetic angular momentum. It provides a more economical and unified description, since each trajectory contains an infinite number of points corresponding to the same statistics. For a system of non-interacting anyons in a harmonic potential, each

Joseph A. Minahan, Dennis Nemeschansky

In this paper we discuss the hyperelliptic curve for $N=2$ $SU(3)$ super Yang-Mills with six flavors of hypermultiplets. We start with a generic genus two surface and construct the curve in terms of genus two theta functions. From this one can construct the curve for $m_i=u=0$. This curve is explicitly dual under a subgroup of $Sp(4,Z)$ which is not isomorph

Mircea Pigli

Incorporating the zonal spherical function (zsf) problems on real and $p$-adic hyperbolic planes into a Zakharov-Shabat integrable system setting, we find a wide class of integrable evolutions which respect the number-theoretic properties of the zsf problem. This means that at {\it all} times these real and $p$-adic systems can be unified into an adelic syst

A. Yu. Smirnov

With latest experimental data the solar neutrino problem enters new phase when crucial aspects of the problem can be formulated in an essentially (solar) model independent way. Original neutrino fluxes can be considered as free parameters to be found from the solar neutrino experiments. Resonance flavour conversion gives the best fit of all experimental resu

Joannis Papavassiliou, Apostolos Pilaftsis

We present a new gauge-independent approach to resonant transition amplitudes with nonconserved external currents, based on the pinch technique method. In the context of $2\to 2$ and $2\to 3$ scattering processes, we show explicitly that the analytic results derived respect $U(1)_{em}$ gauge symmetry and do not depend on the choice of the $SU(2)_L$ gauge fix

M. Cacciari, G. Montagna, O. Nicrosini, F. Piccinini

SABSPV is a code designed to perform a theoretical evaluation of small-angle Bhabha scattering cross sections by suitably matching fixed-order perturbative calculations and structure-function techniques. The implementation of realistic experimental triggering conditions is achieved by using Monte Carlo integration.

T. Kobayashi

We study left-right symmetric quark mass matrices whose up- and down-sectors have the same structure. This type of realistic mass matrices are derived from orbifold models. We cannot derive some of them by using an extra U(1) symmetry.

V. V. Kiselev

In the framework of renormalon consideration, a role of the anomalous dependence of gluon propagator on the scale $μ$ is shown for a large number of quark flavours as well as in the nonabelian theory, where the parameter of the &#34;running&#34; coupling constant evolution has a hidden dependence on the scale. A phenomenological matching between the modified

A. V. Berezhnoy, V. V. Kiselev, A. K. Likhoded

In the framework of QCD perturbation theory, total and differential cross sections of the $Ξ_{bc}&#39;$, $Ξ_{bc}^{(*)}$ and $Ξ_{cc}^{(*)}$ baryons production in gluon collisions are calculated in the leading order over $α_s$ for the doubly heavy ($b c$) and ($ c c$) diquarks. At both small and large transverse momenta of the baryons, a use of the mechanism o

Vipul Periwal

Lepage and Mackenzie have shown that tadpole renormalization and systematic improvement of lattice perturbation theory can lead to much improved numerical results in lattice gauge theory. It is shown that lattice perturbation theory using the Cayley parametrization of unitary matrices gives a simple analytical approach to tadpole renormalization, and that th

F. Niedermayer, Peter Weisz, Dong-Shin Shin

We argue that there is no essential violation of universality in the continuum limit of mixed $\RPn$ and $\On$ lattice sigma models in 2 dimensions, contrary to opposite claims in the literature.

Claude Bernard, Maarten Golterman

We investigate how Lüscher&#39;s relation between the finite-volume energy of two pions at rest and pion scattering lengths has to be modified in quenched QCD. We find that this relation changes drastically, and in particular, that ``enhanced finite-volume corrections&#34; of order $L^0=1$ and $L^{-2}$ occur at one loop ($L$ is the linear size of the box), d

Giampiero Esposito, Giuseppe Pollifrone

This paper studies the two-component spinor form of massive spin-3/2 potentials in conformally flat Einstein four-manifolds. Following earlier work in the literature, a non-vanishing cosmological constant makes it necessary to introduce a supercovariant derivative operator. The analysis of supergauge transformations of primary and secondary potentials for sp

Giampiero Esposito, Gabriele Gionti, Alexander Yu. Kamenshchik, Igor V. Mishakov

This paper studies the two-spinor form of the Rarita-Schwinger potentials subject to local boundary conditions compatible with local supersymmetry. The massless Rarita-Schwinger field equations are studied in four-real-dimensional Riemannian backgrounds with boundary. Gauge transformations on the potentials are shown to be compatible with the field equations

M. Rainer, H. -J. Schmidt

Space-times which allow a slicing into homogeneous spatial hypersurfaces generalize the usual Bianchi models. One knows already that in these models the Bianchi type may change with time. Here we show which of the changes really appear. To this end we characterize the topological space whose points are the 3-dimensional oriented homogeneous Riemannian manifo

Lior M. Burko

The formalism developed by Chandrasekhar for the linear polar perturbations of the Reissner-Nordstrom solution is generalized to include the case of dipole (l=1) perturbations. Then, the perturbed metric coefficients and components of the Maxwell tensor are computed.

A. Moreo, A. Nazarenko, S. Haas, A. Sandvik

We review the results of an extensive investigation of photoemission spectral weight using electronic models for the high-Tc superconductors. Here we show that some recently reported unusual features of the cuprates namely the presence of (i) flat bands, (ii) small quasiparticle bandwidths, and (iii) antiferromagnetically induced weight, have all a natural e

Colin Denniston, Chao Tang

We study a Josephson junction ladder in a magnetic field in the absence of charging effects via a transfer matrix formalism. The eigenvalues of the transfer matrix are found numerically, giving a determination of the different phases of the ladder. The spatial periodicity of the ground state exhibits a devil&#39;s staircase as a function of the magnetic flux

Henrik Bruus, Jean-Christian Angles d&#39;Auriac

Using group theoretical and numerical methods we have calculated the exact energy spectrum of the two-dimensional Hubbard model on square lattices with four electrons for a wide range of the interaction strength. All known symmetries, i.e.\ the full space group symmetry, the SU(2) spin symmetry, and, in case of a bipartite lattice, the SU(2) pseudospin symme

Hyunwoo Lee, L. S. Levitov

We study zero temperature fluctuations of charge flow in a metallic loop induced by time dependent magnetic flux, and solve for the optimal way of varying flux in order to minimize noise. Optimal time dependence of the flux is a sum of ``solitons,&#39;&#39; each corresponding to quantized flux change. Minimal noise coincides with that for the binomial distri

M T Batchelor, C M Yung

The O(n) loop model on the honeycomb lattice with mixed ordinary and special boundary conditions is solved exactly by means of the Bethe ansatz. The calculation of the dominant finite-size corrections to the eigenspectrum yields the mixed boundary scaling index and the geometric scaling dimensions describing the universal surface critical behaviour. Exact re

José M. Goñi, José C. González

In this paper we present a unification-based lexical platform designed for highly inflected languages (like Roman ones). A formalism is proposed for encoding a lemma-based lexical source, well suited for linguistic generalizations. From this source, we automatically generate an allomorph indexed dictionary, adequate for efficient processing. A set of softwar

R. Bijker, A. E. L. Dieperink, A. Leviatan

A new spectrum generating algebra for a unified description of rotations and vibrations in polyatomic molecules is introduced. An application to nonlinear X$_3$ molecules shows that this model (i) incorporates exactly the relevant point group, (ii) provides a complete classification of oblate top states, and (iii) treats properly both degenerate and nondegen

Guillaume Evrard, Peter Coles

The problem of estimating cosmological parameters such as $Ω$ from noisy or incomplete data is an example of an inverse problem and, as such, generally requires a probablistic approach. We adopt the Bayesian interpretation of probability for such problems and stress the connection between probability and information which this approach makes explicit. This c

Wolfgang Brandner, Juan M. Alcala, Michael Kunkel, Andrea Moneti

We present first results of a survey for companions among X-ray selected pre-main sequence stars, most of them being weak-line T Tauri stars (WTTS). These T Tauri stars have been identified in the course of optical follow-up observations of sources from the ROSAT All Sky Survey associated with star forming regions. The areas surveyed include the T associatio

C. T. Falk, H. Falk

This work approaches human chromosome mapping by developing algorithms for ordering markers associated with radiation hybrid data. Motivated by recent work of Boehnke et al. [1], we formulate the ordering problem by developing stochastic spin models to search for minimum-break marker configurations. As a particular application, the methods developed are appl

Adrian Ghinculov

The leading $m_H$ radiative correction to the Higgs decay width into a pair of weak vector bosons is calculated at the two--loop level, using the equivalence theorem in Landau gauge. The result indicates the breakdown of perturbation theory if the Higgs boson is heavier than $\sim 930$ GeV, in spite of the smallness of the one--loop radiative correction.

Thomas Fricke, Dietmar Wendt

We describe a new algorithm for simulating complex Markoff-processes. We have used a reaction-cell method in order to simulate arbitrary reactions. It can be used for any kind of RDS on arbitrary topologies, including fractal dimensions or configurations not being related to any spatial geometry. The events within a single cell are managed by an event handle

T. Kloesch, T. Strobl

We construct coordinate systems that cover all of the Reissner-Nordstroem solution with m>|q| and m=|q|, respectively. This is possible by means of elementary analytical functions. The limit of vanishing charge q provides an alternative to Kruskal which, to our mind, is more explicit and simpler. The main tool for finding these global charts is the descripti

Germán Rodrigo

I make a short review of the most recent determinations of the quark masses and run them to the $M_Z$ energy scale.

J. L. Alonso, Ph. Boucaud, F. Lesmes, A. J. van der Sijs

We study the relation between the Roma and Zaragoza proposals for chiral fermions on the lattice. The fermion action in the Roma approach is shown to be equivalent to one of the Zaragoza type. This result is used to perform a mean-field study of the phase diagram for chiral Yukawa models based on the Roma action. The phase diagram is compared with the one ba

V. Konyshev, I. Polyubin

Radiative corrections in the order ${α\over{2π}}{{m^2_e}\over m^2_μ}$ to $μ$- and ${α\over{2π}}{{m^2_μ}\over m^2_τ}$ to $τ$- decays are calculated. The decay width is enhanced by $4.48\cdot 10^{-3} ({α\over{2π}})$ in the muon case and by $0.283 ({α\over{2π}})$ for the $τ\rightarrow μν_τ\barν_μ(γ)$ decay. Influence of these corrections on the electroweak data

V. V. Kiselev

The width of $B_c^+\to ψπ^+$ decay is calculated in the framework of factorization of a hard gluon exchange and a soft binding of quarks in the heavy quarkonium, so that ${\rm BR}(B_c^+\to ψπ^+) = 2.0\pm 0.5$ \%.

O. M. Khudaverdian, A. Nersessian

The correspondence between the BV-formalism and integration theory on supermanifolds is established. An explicit formula for the density on a Lagrangian surface in a superspace provided with an odd symplectic structure and a volume form is proposed.

Gia Dvali, Alejandra Melfo, Goran Senjanovic

We investigate the high temperature behavior of SU(5) in its minimal version. We show that there exists a range of parameters of the Higgs potential for which the symmetry remains broken at high temperature, thus avoiding the phase transition that gives rise to the overproduction of monopoles . We also show that in such scenario the thermal production of mon

JM Figueroa-O&#39;Farrill

A large class of two-dimensional topological conformal field theories (TCFTs) are obtained by the twisting construction of Witten and Eguchi-Yang. However there seem to exist TCFTs which are not obtained in this way; for instance, TCFTs obtained from the Kazama algebra and critical string theories with generic background. We will show that by embedding the c

Lior M. Burko, Amos Ori

In a recent paper, we discussed the formation of black holes in non-symmetric gravity. That paper was then criticized by Cornish and Moffat. In the present paper, we address the arguments raised by Cornish and Moffat. In summary, we do not see any reason to doubt the validity of our former conclusions.

Kari Enqvist, Katri Huitu, P. N. Pandita

We consider thermal properties of the susy singlet majoron model. We compute the critical temperature $T_c$ and the subsequent reheating temperature $T_{\rm RH}$ for $R$-parity breaking. Succesful baryogenesis constrains the parameter space via the requirements that $T_c$ and $T_{\rm RH}$ are lower than the electroweak phase transition temperature. A further

Yves Laszlo, Christoph Sorger

Let $X$ be a smooth, complete and connected curve and $G$ be a simple and simply connected algebraic group over $\comp$. We calculate the Picard group of the moduli stack of quasi-parabolic $G$-bundles and identify the spaces of sections of its members to the conformal blocs of Tsuchiya, Ueno and Yamada. We describe the canonical sheaf on these stacks and sh

Renata Kallosh, Andrei Linde

We study special points in the moduli space of vacua at which supersymmetric electric solutions of the heterotic string theory become massless. We concentrate on configurations for which supersymmetric non-renormalization theorem is valid. Those are ten-dimensional supersymmetric string waves and generalized fundamental strings with SO(8) holonomy group. Fro

Ph. Blanchard, P. Garbaczewski, R. Olkiewicz

The existing formulations of the Schrödinger interpolating dynamics, which is constrained by the prescribed input-output statistics data, utilize strictly positive Feynman-Kac kernels. This implies that the related Markov diffusion processes admit vanishing probability densities only at the boundaries of the spatial volume confining the process. We extend th

Hungchong Kim, S. Schramm, C. J. Horowitz

We derive the contribution of $Δ$-h excitations to quasielastic charged-current neutrino-nucleus scattering in the framework of relativistic mean-field theory. We discuss the effect of $Δ$ production on the determination of the axial mass $M_A$ in neutrino scattering experiments.

I. S. Towner, E. Hagberg, J. C. Hardy, V. T. Koslowsky

Data on superallowed Fermi beta decay in nuclei are compiled and electromagnetic corrections discussed. Recommended values for the weak vector coupling constant and the leading element of the Cabibbo-Kobayashi-Maskawa mixing matrix are given. Comments on neutron decay and limits extracted on extensions to the Standard Model are made.

I. S. Towner, E. Hagberg, G. Savard, J. C. Hardy

Two experiments, (1) a measurement of the superallowed $0^{+} \rightarrow 0^{+}$ branching ratio in $^{10}$C, and (2) a measurement of (or limit on) non-analogue $0^{+} \rightarrow 0^{+}$ branches in $^{38m}$K, $^{46}$V, $^{50}$Mn and $^{54}$Co, are described. The implications these experiments have on the test of the conservation of the weak vector current

R. Schaefer, R. Blendowske

An algorithm for the numerical solution of the Schrödinger equation in the case of a time dependent potential is proposed. Our simple modification upgrades the well known method of Koonin while negligibly increasing the computing time. In the presented test the accuracy is enhanced by up to an order of magnitude.

Moti Gitik

The purpose of the paper is to produce models V_1 \subset V_2 such that adding kappa-many Cohen reals to V_2 adds lambda Cohen reals to V_1. Some of the results: 1. Suppose that V satisfies GCH, kappa = \cup kappa_n= \cup o(kappa_n). Then there is a cardinal preserving generic extension V_1 of V satisfying GCH and having the same reals as V does , so that ad

Moti Gitik, Saharon Shelah

Answering two questions of D. Fremlin [Real-valued measurable cardinals, in Set Theory of the Reals, H. Judah ed. 1993, 151-305 ] we show the following: (1) If c is real-valued measurable then the Maharam type of (c,P(c),sigma) is 2^c. (2) It is consistent to have k real-valued measurable but for every submodel V_1 with k measurable in it there are no k real