April 1995 arXiv papers — page 5

D. M. Christodoulou, D. Kazanas, I. Shlosman, J. E. Tohline

We use a free-energy minimization approach to describe the secular and dynamical instabilities as well as the bifurcations along equilibrium sequences of rotating, self-gravitating fluid systems. Our approach is fully nonlinear and stems from the Ginzburg-Landau theory of phase transitions. In this paper, we examine fourth-harmonic axisymmetric disturbances

Ted Pyne, Mark Birkinshaw

We obtain analytic formulae for the null geodesics of Friedmann-Lema\^ıtre-Robertson-Walker spacetimes with scalar perturbations in the longitudinal gauge. From these we provide a rigorous derivation of the cosmological lens equation, and obtain an expression for the magnification of a bundle of light rays without restriction to static or thin lens scenarios

M. Bobrowsky, A. A. Zijlstra, E. K. Grebel, C. G. Tinney

We present spectra and high-resolution images taken with HST, the NTT, the VLA, and the MPIA/ESO 2.2m of the emission-line star He 3-1475 which we suggest is a post-AGB star. The star is at the origin of a 15-arcsec-long structure containing symmetrically opposing bright knots. The knots have radial velocities of about 500 km/s from the center of He 3-1475 t

L. Schuelke, B. Zheng

The universal behaviour of the short-time dynamics of the three state Potts model in two dimensions at criticality is investigated with Monte Carlo methods. The initial increase of the order is observed. The new dynamic exponent $θ$ as well as exponent $z$ and $β/ν$ are determined. The measurements are carried out in the very beginning of the time evolution.

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

The decays of $B$ mesons to two-body hadronic final states are analyzed within the context of broken flavor SU(3) symmetry, extending a previous analysis involving pairs of light pseudoscalars to decays involving one or two charmed quarks in the final state. A systematic program is described for learning information {}from decay rates regarding (i) SU(3)-vio

Wayne Hu, Naoshi Sugiyama, Joseph Silk

Cosmic microwave background anisotropies provide a vast amount of information on both structure formation in the universe and the background dynamics and geometry. The full physical content and detailed structure of anisotropies can be understood in a simple and intuitive fashion through a systematic investigation of the individual mechanisms for anisotropy

P. K. Townsend

The conjectured equivalence of the heterotic string to a $K_3$ compactified type IIA superstring is combined with the conjectured equivalence of the latter to a compactified 11-dimensional supermembrane to derive a string membrane duality in seven dimensions; the membrane is a soliton of the string theory and vice versa. A prediction of this duality is that

Julyan H. E. Cartwright, Mario Feingold, Oreste Piro

We discuss chaotic advection in three-dimensional unsteady incompressible laminar flow, and analyse in detail the most important novel advection phenomenon in these flows; the global dispersion of passive scalars in flows with two slow and one fast velocity components. We make a comprehensive study of the first model of an experimentally realizable flow to e

F. Courbin, P. Magain, M. Remy, A. Smette

We present the results of a 7 year long photometric monitoring of two components (A and B) of UM 425, thought to be images, separated by 6.5", of the same z = 1.47 quasar. These components have been imaged through an R filter in order to obtain their light curves. The photometry was obtained by simultaneously fitting a stellar two-dimensional profile on each

W. Barten, M. Luecke, M. Kamps, R. Schmitz

Nonlinear, spatially localized structures of traveling convection rolls are investigated in quantitative detail as a function of Rayleigh number for two different Soret coupling strengths (separation ratios) with Lewis and Prandtl numbers characterizing ethanol-water mixtures. A finite-difference method was used to solve the full hydrodynamic field equations

W. Barten, M. Luecke, M. Kamps, R. Schmitz

Nonlinear convection structures are investigated in quantitative detail as a function of Rayleigh number for several negative and positive Soret coupling strengths (separation ratios) and different Lewis and Prandtl numbers characterizing different mixtures. A finite difference method was used to solve the full hydrodynamic field equations in a range of expe

P. Navratil, H. B. Geyer, J. Dobaczewski

We construct finite Dyson boson-fermion mappings of general collective algebras extended by single-fermion operators. A key element in the construction is the implementation of a similarity transformation which transforms boson-fermion images obtained directly from the supercoherent state method. In addition to the general construction, we give detailed appl

Martin Goldstern

We give a simple example of a set that is weakly Dedekind infinite (= can be mapped onto omega) but dually Dedekind finite (=cannot be mapped noninjectively onto itself), namely, the power set of a superamorphous set. (A infinite set is superamorphous if all finitary relations on it are definable in the language of equality.) We also show that the property o

Erling G. B. Hohler, Kåre Olaussen

We investigate the question of how the knowledge of sufficiently many local conservation laws for a model can be utilized to solve the model. We show that for models where the conservation laws can be written in one-sided forms, like $\barpartial Q_s = 0$, the problem can always be reduced to solving a closed system of ordinary differential equations. We inv

Michio Ikehara

Through the continuum limit of the one matrix model on the multicritical point the corresponding Schwinger-Dyson equation of temporal-gauge string field theory is derived. It agrees with that of the background independent formulation recently proposed.

E. Elizalde, S. D. Odintsov

We study a renormalizable, general theory of dilatonic gravity (with a kinetic-like term for the dilaton) interacting with scalar matter near two dimensions. The one-loop effective action and the beta functions for this general theory are written down. It is proven that the theory possesses a non-trivial ultraviolet fixed point which yields an asymptotically

L. Griguolo, R. Percacci

We study a scalar field theory coupled to gravity on a flat background, below Planck's energy. Einstein's theory is treated as an effective field theory. Within the context of Wilson's renormalization group, we compute gravitational corrections to the beta functions and the anomalous dimension of the scalar field, taking into account threshold ef

Andrew Strominger

Low-energy effective field theories arising from Calabi-Yau string compactifications are generically inconsistent or ill-defined at the classical level because of conifold singularities in the moduli space. It is shown, given a plausible assumption on the degeneracies of black hole states, that for type II theories this inconsistency can be cured by nonpertu

Jan C. Plefka

The double-scaling limit of the supereigenvalue model is performed in the moment description. This description proves extremely useful for the identification of the multi-critical points in the space of bosonic and fermionic coupling constants. An iterative procedure for the calculation of higher-genus contributions to the free energy and to the multi-loop c

D. Korotkin, H. Nicolai

We present a new quantization scheme for $2D$ gravity coupled to an $SU(2)$ principal chiral field and a dilaton; this model represents a slightly simplified version of stationary axisymmetric quantum gravity. The analysis makes use of the separation of variables found in our previous work [1] and is based on a two-time hamiltonian approach. The quantum cons

S. Baker, V. Z. Enolskii, A. P. Fordy

We show a surprising connection between known integrable Hamiltonian systems with quartic potential and the stationary flows of some coupled KdV systems related to fourth order Lax operators. In particular, we present a connection between the Hirota-Satsuma coupled KdV system and (a generalisation of) the $1:6:1$ integrable case quartic potential. A generali

Nick Dorey, Michael Mattis

The perceived inability of the Skyrme model to reproduce pseudovector pion-baryon coupling has come to be known as the ``Yukawa problem.'' In this talk, we review the complete solution to this problem. The solution involves a new configuration known as the rotationally improved Skyrmion, or ``RISKY,'' in which the hedgehog structure is modifi

Nick Dorey, Michael Mattis

In this talk we review how effective theories of mesons and baryons become exactly soluble in the large-N_c limit. We start with a generic hadron Lagrangian constrained only by certain well-known large-N_c selection rules. The bare vertices of the theory are dressed by an infinite class of UV divergent Feynman diagrams at leading order in 1/N_c. We show how

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

We discuss the role of electroweak penguins in $B$ decays to two light pseudoscalar mesons. We confirm that the extraction of the weak phase $α$ through the isospin analysis involving $B\toππ$ decays is largely unaffected by such operators. However, the methods proposed to obtain weak and strong phases by relating $B\toππ$, $B\toπK$ and $B\to KK$ decays thro

Carleton DeTar

Numerical simulations of quantum chromodynamics at nonzero temperature provide information from first principles about the physical properties of the quark gluon plasma. Because the lattice approximation can be refined indefinitely, results of lattice simulations now provide the most reliable basis for our understanding of the nonperturbative characteristics

M. Drees, S. P. Martin

We discuss the motivations and implications of models of low-energy supersymmetry. We present the case for the minimal supersymmetric standard model, which we define to include the minimal particle content and soft supersymmetry-breaking interactions which are universal at the GUT or Planck scale. This model is in agreement with all present experimental resu

C. D. Froggatt

Different approaches to the quark-lepton mass problem are reviewed. The infrared quasifixed point predictions for the top quark mass are discussed for the Standard Model and its minimal supersymmetric extension, with particular reference to the large $\tanβ$ scenario and Yukawa unification. Mass matrix ansätze with texture zeros at the unification scale are

J. Engel, M. T. Ressell, I. S. Towner, W. E Ormand

We calculate spin-dependent cross sections for the scattering from mica of hypothetical weakly interacting dark-matter particles such as neutralinos. The most abundant odd-A isotopes in mica, Al27 and K39, require different shell-model treatments. The calculated cross sections will allow the interpretation of ongoing experiments that look for tracks due to t

Kurt Riesselmann

The equivalence theorem is an extremely useful tool to calculate heavy Higgs {\it and} top-quark effects for processes that have center-of-mass-energies (much) larger than the $W$ boson mass. After an explanation of the renormalization procedures involved, the results for one- and two-loop radiative corrections to the fermionic Higgs decay, $H\rightarrow f\b

J. D. Vergados

The differential cross-section for the elastic scattering of the lightest supersymmetric particle (LSP) with nuclear targets is calculated in the context of currently fashionable supersymmetric theories (SUSY). An effective four fermion interaction is constructed by considering i) $Z^0$ exchange ii)s-quark exchange and iii) Higgs exchange. It is expressed in

S. S. Gershtein, V. V. Kiselev, A. K. Likhoded, A. V. Tkabladze

In the framework of potential models for heavy quarkonium the mass spectrum for the system ($\bar b c$) is considered. Spin-dependent splittings, taking into account a change of a constant for effective coulomb interaction between the quarks, and widths of radiative transitions between the ($\bar b c$) levels are calculated. In the framework of QCD sum rules

Shigetaka Moriyama

A new experimental scheme is proposed to search for almost monochromatic solar axions, whose existence has not been discussed heretofore. The axions would be produced when thermally excited $^{57}$Fe in the sun relaxes to its ground state and could be detected via resonant excitation of the same nuclide in a laboratory. A detailed calculation shows that the

G. Fleming, J. Greensite

We investigate whether information about Creutz ratios is encoded, separately, in each gluon color component of numerically generated lattice configurations. Working in SU(2) lattice gauge theory in Landau gauge, we set two of the three gluon color components to zero, and compensate for the loss of two-thirds of the fluctuation by simply rescaling the remain

M. P. Dabrowski, A. L. Larsen

It is shown that the tunneling effect in quantum cosmology is possible not only at the very beginning or the very end of the evolution, but also at the moment of maximum expansion of the universe. A positive curvature expanding Friedmann universe changes its state of evolution spontaneously and completely, {\it without} any changes in the matter content, avo

Ruy Exel

The dual action of a locally compact abelian group, in the context of C*-algebraic bundles, is shown to satisfy an integrability property, similar to Rieffel's proper actions. The tools developed include a generalization of Bochner's integral as well as a Fourier inversion formula for operator valued maps.

S. Sakhi, P. Vasilopoulos

The possibility of charge density oscillations in a {\it finite-thickness} two-dimensional system is investigated for strong magnetic fields and integer filling factors. Using an effective action formalism, it is shown that an {\it oscillatory charge density} (OCD) is generated in a self-consistent way and is favored energetically over homogeneous distributi

J. K. Jain, Sumathi Rao

Motivated by a mean-field approach, which has been employed for anyon superfluidity and the fractional quantum Hall effect, the quantum Hall effect (QHE) of hard-core bosons is investigated. It is shown that QHE is possible {\em only} in the thermodynamic limit. The filling factors where QHE may be expected are obtained with the help of two adiabatic schemes

Andreas Schönenberger, Vadim Geshkenbein, Gianni Blatter

Based on the London approximation, we investigate numerically the stability of the elementary configurations of entanglement, the twisted-pair and the twisted-triplet, in the vortex-lattice and -liquid phases. We find that, except for the dilute limit, the twisted-pair is unstable and hence irrelevant in the discussion of entanglement. In the lattice phase t

Mary Dalrymple, John Lamping, Fernando Pereira, Vijay Saraswat

Semantic theories of natural language associate meanings with utterances by providing meanings for lexical items and rules for determining the meaning of larger units given the meanings of their parts. Meanings are often assumed to combine via function application, which works well when constituent structure trees are used to guide semantic composition. Howe

W. T. Reach, E. Dwek, D. J. Fixsen, T. Hewagama

We derive Galactic continuum spectra from 5-96/cm from COBE/FIRAS observations. The spectra are dominated by warm dust emission, which may be fit with a single temperature in the range 16-21 K (for nu^2 emissivity) along each line of sight. Dust heated by the attenuated radiation field in molecular clouds gives rise to intermediate temperature (10-14 K) emis

Günter Wunner, Robert Sang, Dagmar Berg

We reassess the importance of photon splitting to spectral formation in cosmic X-ray and $γ$-ray sources with magnetic fields of several $10^{12}$ gauss. Our analysis is based on the recent numerically accurate evaluation of the full relativistic expression for photon splitting at neutron star magnetic field strengths (Mentzel et al. 1994). Using these resul

Lloyd Knox

Inflation produces nearly Harrison-Zel'dovich scalar and tensor perturbation spectra which lead to anisotropy in the cosmic microwave background (CMB). The amplitudes and shapes of these spectra can be parametrized by $Q_S^2$, $r\equiv Q_T^2/Q_S^2$, $n_S$ and $n_T$ where $Q_S^2$ and $Q_T^2$ are the scalar and tensor contributions to the square of the CMB

M. Carena, J. R. Espinosa, M. Quiros, C. E. M. Wagner

We propose, for the computation of the Higgs mass spectrum and couplings, a renormalization-group improved leading-log approximation, where the renormalization scale is fixed to the top-quark pole mass. For the case $m_A\sim M_{\rm SUSY}$, our leading-log approximation differs by less than 2 GeV from previous results on the Higgs mass computed using a nearly

Simone Artz, Luca Mezincescu, Rafael I. Nepomechie

We determine the eigenvalues of the transfer matrices for integrable open quantum spin chains which are associated with the affine Lie algebras $A^{(2)}_{2n-1}, B^{(1)}_n, C^{(1)}_n, D^{(1)}_n$, and which have the quantum-algebra invariance U_q(C_n), U_q(B_n), U_q(C_n), U_q(D_n)$, respectively.

Oleg Andreev

Structure constants of Operator Algebras for the SL(2) degenerate conformal field theories are calculated.

Ganesh Devaraj, Martin B. Einhorn

We investigate the massless $λϕ^4$ theory in de~Sitter space. It is unnatural to assume a minimally coupled interacting scalar field, since $ξ=0$ is not a fixed point of the renormalization group once interactions are included. In fact, the only case where perturbation theory can be trusted is when the field is non-minimally coupled at the minimum of the eff

Mathias Pillin

It is shown how the different irreducibility classes of the energy-momentum tensor allow for a Lagrangian formulation of the gravity-matter system using a selfdual 2-form as a basic variable. It is pointed out what kind of difficulties arise when attempting to construct a pure spin-connection formulation of the gravity-matter system. Ambiguities in the formu

O. Yu. Shvedov

The problem of finding the large order asymptotics for the eigenfunction perturbation theory in quantum mechanics is studied. The relation between the wave function argument x and the number of perturbation theory order k that allows us to construct the asymptotics by saddle-point technique is found: $x/k^{1/2}=const$, k is large. Classical euclidean solutio

Timo Weidl

Let $E_i(H)$ denote the negative eigenvalues of the one-dimensional Schrödinger operator $Hu:=-u^{\prime\prime}-Vu,\ V\geq 0,$ on $L_2({\Bbb R})$. We prove the inequality \sum_i|E_i(H)|^γ\leq L_{γ,1}\int_{\Bbb R} V^{γ+1/2}(x)dx, (1) for the &#34;limit&#34; case $γ=1/2.$ This will imply improved estimates for the best constants $L_{γ,1}$ in (1), as $1/2<γ<3/2

O. Yu. Shvedov

A new approach to the problem of finding the asymptotical behaviour of large orders of semiclassical expansion is suggested. Asymptotics of high orders not only for eigenvalues, but also for eigenfunctions, are constructed. Thus, one can apply not only functional integral technique, which has been used up to now, but also method of direct analysis of the sem

Ashok Das, Marcelo Hott

We show that the formation of condensates in the presence of a constant magnetic field in 2+1 dimensions is extremely unstable. It disappears as soon as a heat bath is introduced with or without a chemical potential. We point out some new nonanalytic behavior that develops in this system at finite temperature.

S. Krivonos, A. Sorin

We show that the well known $N=1$ NLS equation possesses $N=2$ supersymmetry and thus it is actually the $N=2$ NLS equation. This supersymmetry is hidden in terms of the commonly used $N=1$ superfields but it becomes manifest after passing to the $N=2$ ones. In terms of the new defined variables the second Hamiltonian structure of the supersymmetric NLS equa

M. GasperinI, M. Giovannini, G. Veneziano

Sufficiently large seeds for generating the observed (inter)galactic magnetic fields emerge naturally in string cosmology from the amplification of electromagnetic vacuum fluctuations due to a dynamical dilaton background. The success of the mechanism depends crucially on two features of the so-called pre-big-bang scenario, an early epoch of dilaton-driven i

D. K. Park

Light-cone quantization procedure recently presented is applied to the two-dimensional light-cone theories. By introducing the two distinct null planes it is shown that the modification term in the two-dimensional massless light-cone propagators suggested about twenty years ago vanishs.

Tatsu Takeuchi, Aaron K. Grant, Mihir P. Worah

We discuss the difficulties that arise when one tries to calculate $δρ$ using dispersion relations.

T. L. Trueman

A set of procedures is given for avoiding the spurious anomalies that are generated when the &#39;t Hooft - Veltman definition of gamma5 is used in conjunction with renormalization by minimal subtraction. These procedures are derived from the standard procedure, which requires in addition various finite renormalizations to remove spurious violations of chira

Gautam Bhattacharyya, Debajyoti Choudhury, K. Sridhar

We use the precision electroweak data at LEP to place bounds on $B$-violating Yukawa couplings, two theoretically appealing examples being provided by $R$-parity--violating supersymmetry and diquarks. The couplings involving the third generation quarks are most severely constrained. These bounds are complementary to those obtained from low-energy processes.

Kiselev V.

In the framework of a specific scheme of the QCD sum rules for $S$-wave levels of the heavy quarkonium, one derives expressions, relating the leptonic constants, the energetic density of quarkonium states and universal characteristics in the heavy quarkonium physics, such as the difference between the masses of heavy quark $Q$ and meson $(Q\bar q)$ and the n

Yosef Nir

The hierarchy in the Yukawa couplings may be the result of a gauged horizontal $U(1)_H$ symmetry. If the mixed anomalies of the Standard Model gauge group with $U(1)_H$ are cancelled by a Green-Schwarz mechanism, a relation between the gauge couplings, the Yukawa couplings and the $μ$-term arises. Assuming that at a high energy scale $g_3^2=g_2^2={5\over3}g_

Wei-Shu Hou, Gwo-Guang Wong

With $μ\to eγ$ decay forbidden by multiplicative lepton number conservation, we study muonium--antimuonium transitions induced by neutral scalar bosons. Pseudoscalars do not induce conversion for triplet muonium, while for singlet muonium, pseudoscalar and scalar contributions add constructively. This is in contrast to the usual case of doubly charged scalar

W. Janke, H. Kleinert

We review the dual relationship between various compact U(1) lattice models and Abelian Higgs models, the latter being the disorder field theories of line-like topological excitations in the systems. We point out that the predicted first-order transitions in the Abelian Higgs models (Coleman-Weinberg mechanism) are, in three dimensions, in contradiction with

Yu. G. Gurevich, O. Yu. Titov, G. N. Logvinov, O. I. Lyubimov

The thermoemf in bipolar semiconductors is calculated. It is shown that it is necessary to take into account the nonequilibrium distribution of electron and hole concentrations (Fermi quasilevels of the electrons and holes). We find that electron and hole electric conductivities of contacts of semiconductor samples with connecting wires make a substantial co

A. K. Hartmann

We present an algorithm which calculates groundstates of Ising spin glasses approximately. It works by randomly selecting clusters of spins which exhibit no frustrations. The spins which were not selected, contribute to the local fields of the selected spins. For the spin--cluster a groundstate is exactly calaculated by using graphtheoretical methods. The ot

O. Derzhko, T. Krokhmalskii

The paper presents a new numerical approach for studying the thermodynamical and dynamical properties of finite spin-$\frac{1}{2}$ $XY$ chains. Special attention is given to examining the influence of disorder on the average transverse dynamical susceptibility of Ising chain in random transverse field.

P. Sikivie, I. I. Tkachev, Yun Wang

The cold dark matter spectrum on earth is expected to have peaks in velocity space. We obtain estimates for the sizes and locations of these peaks. To this end we have generalized the secondary infall model of galactic halo formation to include angular momentum of the dark matter particles. This new model is still spherically symmetric and it has self-simila

Yasushi Maeno, Dr. Y-h. Taguchi

Surface level instability when tube is injected into vibrating bed of powder, which was originally found in experiments, is investigated numerically. We find that thicker (thiner) tube makes surface level inside tube higher (lower) than surface level outside tube. With fixed acceleration amplitude of vibration, surface level inside tube becomes higher as amp

Krishna Rajagopal

In QCD with two massless quarks, the chiral phase transition is plausibly in the same universality class as the classical O(4) magnet. To test this hypothesis, critical exponents characterizing the behaviour of universal quantities near the 2nd order critical point can be calculated and compared to results from lattice simulations. Present simulations alread

Mark Abney, Richard I Epstein

We examine the dynamics of a rotating viscous fluid following an abrupt change in the angular velocity of the solid bounding surface. We include the effects of a density stratification and compressibility which are important in astrophysical objects such as neutron stars. We confirm and extend the conclusions of previous studies that stratification restricts

E. Bergshoeff, C. M. Hull, T. Ortin

We derive the T-duality transformations that transform a general d=10 solution of the type-IIA string with one isometry to a solution of the type-IIB string with one isometry and vice versa. In contrast to other superstring theories, the T-duality transformations are not related to a non-compact symmetry of a d=9 supergravity theory. We also discuss S-dualit

Yong Baek Kim, Patrick A. Lee, Xiao-Gang Wen

We derive the quantum Boltzmann equation (QBE) of composite fermions at/near the $ν= 1/2$ state using the non-equilibrium Green&#39;s function technique. The lowest order perturbative correction to the self-energy due to the strong gauge field fluctuations suggests that there is no well defined Landau-quasi-particle. Therefore, we cannot assume the existence

S. Elitzur, A. Forge, A. Giveon, E. Rabinovici

We present the exact effective superpotentials in $4d$, $N=1$ supersymmetric $SU(2)$ gauge theories with $N_3$ triplets and $N_2$ doublets of matter superfields. For the theories with a single triplet matter superfield we present the exact gauge couplings for arbitrary bare masses and Yukawa couplings.

H. Kleinert, H. Meyer

Using the new variational approach proposed recently for a systematic improvement of the locally harmonic Feynman-Kleinert approximation to path integrals we calculate the partition function of the anharmonic oscillator for all temperatures and coupling strength with high accuracy.

Jun Li

We determined the Picard group of the moduli of rank two stable sheaves on an arbitrary algebraic surface up to finite index

Jun Li

We determined the first two Betti numbers of the moduli of rank two stable sheaves on an arbitrary algebraic surface

Jun Li, Gang Tian

We established the associativity of the quantum cohomologies of homogeneous varieties by using degeneration method in algebraic geometry.

S. James Gates, Sergei V. Ketov

The structure of on-shell and off-shell 2D, (4,4) supersymmetric scalar multiplets is investigated, in components and in superspace. We reach the surprising result that there exist eight {\underline {distinct}} on-shell versions and an even greater variety of off-shell ones. The off-shell generalised tensor and relaxed N = 4 multiplets are introduced in supe

Masayuki Koike, Toshihiko Nonaka, Tadashi Kon

We investigate the chargino production process $\gamma\gamma\rightarrow\tilde{W}^{+}\tilde{W}^{-}$ at high energy $\gamma\gamma$ colliders in the framework of the minimal supersymmetric standard model (MSSM). Here the high energy $\gamma$ beams are obtained by the backward Compton scattering of the laser flush by the electron in the basic linear TeV $ee$ col

Robin G. Stuart

Unstable particles cannot be treated as asymptotic external states in $S$-matrix theory and when they occur as resonant states cannot be described by finite-order perturbation theory. The known facts concerning unstable particles are reviewed and it is shown how to construct gauge-invariant expressions for matrix elements containing intermediate unstable par

David A. Buote, Claude R. Canizares

We analyzed ROSAT PSPC images of the bright, nearby $(z<0.1)$ galaxy clusters A401, A1656 (Coma), A2029, A2199, and A2256 to constrain their intrinsic shapes and baryon fractions. Following Buote & Tsai we probed the aggregate structure of the clusters on scales $\sim 1.5h^{-1}_{80}$ Mpc to reduce effects of possible substructure on smaller scales ($\lesssim

Hubert Grudzinski

The pseudo--spectral decomposition of an $N$--particle antisymmetric 1--body positive--semidefinite operator that corresponds to the canonical convex decomposition into the extreme elements of the dual cone of the set of fermion $N$--representable $1$--density operators has been derived. An attempt at constucting a mathematical model for collective behaviour

James Cummings, Mirna Džamonja, Saharon Shelah

In this paper we study the notion of strong non-reflection, and its contrapositive weak reflection. We say theta strongly non-reflects at lambda iff there is a function F: theta ---> lambda such that for all alpha < theta with cf(alpha)= lambda there is C club in alpha such that F restriction C is strictly increasing. We prove that it is consistent to have a

Renling Jin, Saharon Shelah

In the paper we probe the possibilities of creating a Kurepa tree in a generic extension of a model of CH plus no Kurepa trees by an omega_1-preserving forcing notion of size at most omega_1. In the first section we show that in the Levy model obtained by collapsing all cardinals between omega_1 and a strongly inaccessible cardinal by forcing with a countabl

Mary K. Gaillard, Hitoshi Murayama, Keith A. Olive

Supersymmetry is generally broken by the non-vanishing vacuum energy density present during inflation. In supergravity models, such a source of supersymmetry breaking typically makes a contribution to scalar masses of order ${\tilde m}^2 \sim H^2$, where $H^2 \sim V/M_P^2$ is the Hubble parameter during inflation. We show that in supergravity models which po

Juan Garcia-Bellido, Andrei Linde

In Brans-Dicke theory the Universe becomes divided after inflation into many exponentially large domains with different values of the effective gravitational constant. Such a process can be described by diffusion equations for the probability of finding a certain value of the inflaton and dilaton fields in a physical volume of the Universe. For a typical cha

Owen Rambow, Aravind K. Joshi

Like many verb-final languages, Germn displays considerable word-order freedom: there is no syntactic constraint on the ordering of the nominal arguments of a verb, as long as the verb remains in final position. This effect is referred to as ``scrambling&#39;&#39;, and is interpreted in transformational frameworks as leftward movement of the arguments. Furth

Matthias Steinmetz

A combined N--body/SPH code is presented which benefits from the high speed of the special purpose hardware GRAPE (GRAvity PipE). Besides gravitational forces, GRAPE also returns the list of neighbours and can, therefore, be used to speed up the hydrodynamical part, too. After the interaction list has been passed, density, pressure forces, propagation and in

Scott Nollet

In this paper we study the problem of describing the integral subschemes within a fixed even linkage class $Ł$ of subschemes in $\Pn$ of codimension two. In the case that $Ł$ is not the class of arithmetically Cohen-Macaulay subschemes, we associate to any $X \in Ł$ two invariants $θ_X$ and $η_X$. When taken with the height $h_X$, each of these invariants de

Chongying Dong, Haisheng Li, Geoffrey Mason

We consider how a vertex operator algebra can be extended to an abelian intertwining algebra by a family of weak twisted modules which are {\em simple currents} associated with semisimple weight one primary vectors. In the case that the extension is again a vertex operator algebra, the rationality of the extended algebra is discussed. These results are appli

A. V. Berezhnoy, A. K. Likhoded, O. P. Yushchenko

Calculations of the hadronic $B^{(*)}_c$-mesons production performed in the framework of the perturbative QCD taking into account $O(α_s^4)$ Feynmann diagrams are presented. A comparison of the exact calculations with those based on the fragmentation model of $\bar b\rightarrow B^{(*)}_c+X$ shows the large discrepancy between them. The exact calculations of

T. S. Biro, S. G. Matinyan, B. Muller

We argue on a basis of a simple few mode model of SU(2) Yang-Mills theory that the color off-diagonal coupling of the soft plasmon to hard thermal excitations of the gauge field drives the collective plasma oscillations into chaotic motion despite the presence of the plasmon mass.

A. Buonanno, M. Gattobigio, M. Maggiore, L. Pilo

We discuss the most general effective Lagrangian obtained from the assumption that the degrees of freedom to be quantized, in a black hole, are on the horizon. The effective Lagrangian depends only on the induced metric and the extrinsic curvature of the (fluctuating) horizon, and the possible operators can be arranged in an expansion in powers of $\mpl/M$,

Vl. S Dotsenko, G. Harris, E. Marinari, E. Martinec

We examine the geometrical and topological properties of surfaces surrounding clusters in the 3--$d$ Ising model. For geometrical clusters at the percolation temperature and Fortuin--Kasteleyn clusters at $T_c$, the number of surfaces of genus $g$ and area $A$ behaves as $A^{x(g)}e^{-μ(g)A}$, with $x$ approximately linear in $g$ and $μ$ constant. These scali

T. Aida, Y. Kitazawa

We evaluate the quantum corrections of the Einstein-Hilbert action with boundaries in the $2+ε$ dimensional expansion approach. We find the Einstein-Hilbert action with boundaries to be renormalizable to the one loop order. We compute the geometric entropy beyond the semiclassical approximation. It is found that the exact geometric entropy is related to the

Peter Bouwknegt, Andreas W. W. Ludwig, Kareljan Schoutens

In this note we review the spinon basis for the integrable highest weight modules of sl2^ at levels k\geq1, and give the corresponding character formula. We show that our spinon basis is intimately related to the basis proposed by Foda et al. in the principal gradation of the algebra. This gives rise to new identities for the q-dimensions of the integrable m

Bing An Li

By applying the Ward identity found by Weinberg two new relations of the amplitude of $a_{1}\rightarrowρπ$ with other physical quantities have been found.

Bing An Li

A $U(2)_{L}\times U(2)_{R}$ chiral theory of pseudoscalar, vector, and axial-vector mesons has been proposed. VMD has been revealed from this theory. The physical processes of normal parity and abnormal parity have been studied by using the same lagrangian and the universality of coupling has been revealed. Two new mass relations between vector and axial-vec

A. V. Sidorov, D. B. Stamenov

The results of LO \it {Fixed Point} QCD (FP - QCD) analysis of the CCFR data for the nucleon structure function $~xF_3(x,Q^2)~$ are presented. The predic- tions of FP - QCD, in which $~α_s(Q^2)~$ tends to a nonzero coupling constant $~α_0~$ as $~Q^2\to \infty~$, are in good agreement with the data. The description of the data is even better than that in the

A. Sopczak

New results from general searches for the Higgs boson of the Minimal Standard Model (MSM), and for neutral and charged Higgs bosons of non-minimal Higgs models are reviewed from the four LEP experiments at CERN: ALEPH, DELPHI, L3, and OPAL. Much progress has been made due to the analysis of new data sets. A total of about 13 million hadronic Z decays are rec

A. Sopczak

The high statistics of the combined LEP lineshape data are used to derive constraints on hypothetical extensions of the Minimal Standard Model. The data comprises about eight million visible Z decays, recorded between 1989 and 1993. This letter gives limits for simple tests on models which predict additional Z boson decays or modified Z-couplings. As an appl

S. Catterall, G. Thorleifsson, M. Bowick, V. John

We examine the scaling of geodesic correlation functions in two-dimensional gravity and in spin systems coupled to gravity. The numerical data support the scaling hypothesis and indicate that the quantum geometry develops a non-perturbative length scale. The existence of this length scale allows us to extract a Hausdorff dimension. In the case of pure gravit