June 1995 arXiv papers — page 10

M. Takizawa, M. Oka

We study the $η\to 2 γ$ decay using an extended three-flavor Nambu-Jona-Lasinio model that includes the 't~Hooft instanton induced interaction. The $η$ meson mass and the $η\to 2 γ$ decay width are reproduced simultaneously with a rather strong instanton induced interaction. The calculated $η$ decay constant is $f_η= 2.23 f_π$ and it suggests that the $η

J. D. Finley, III

The minimal prolongation structure for the Robinson-Trautman equations of Petrov type III is shown to always include the infinite-dimensional, contragredient algebra, K$_2$, which is of infinite growth. Knowledge of faithful representations of this algebra would allow the determination of Bäcklund transformations to evolve new solutions.

Luis P. Chimento, Alejandro S. Jakubi

Several isotropic, homogeneous cosmological models containing a self-interacting minimally coupled scalar field, a perfect fluid source and cosmological constant are solved. New exact, asymptotically stable solutions with an inflationary regime or a final Friedmann stage are found for some simple, interesting potentials. It is shown that the fluid and the cu

R. Loll

We investigate the spectral properties of the volume operator in quantum gravity in the framework of a previously introduced lattice discretization. The presence of a well-defined scalar product in this approach permits us to make definite statements about the hermiticity of quantum operators. We find that the spectrum of the volume operator is discrete, but

Giampiero Esposito

In complex general relativity, Lorentzian space-time is replaced by a four-complex-dimensional complex-Riemannian manifold, with holomorphic connection and holomorphic curvature tensor. A multisymplectic analysis shows that the Hamiltonian constraint is replaced by a geometric structure linear in the holomorphic multimomenta, providing some boundary conditio

W. A. Atkinson, J. P. Carbotte

In this article we consider a simple model for a c--axis Pb/YBa_2Cu_3O_{7-δ} Josephson junction. The observation of a nonzero current in such a junction by Sun et al. [A. G. Sun, D. A. Gajewski, M. B. Maple, R. C. Dynes, Phys. Rev. Lett. 72, 2267 (1994)] has been taken as evidence against d--wave superconductivity in YBa_2Cu_3O_{7-δ}. We suggest, however, th

Daniel P. Arovas, Assa Auerbach

Motivated by the structure of TDAE-\c60, we derive a multicomponent superexchange Hamiltonian for the spins and orbital (``isospin'') degrees of freedom in the Mott-insulating phase. We explore its phase diagram and identify points of special interest: an SU(4) antiferromagnet (solved by Sutherland) and two ferromagnet$\otimes$antiferromagnet points

O. M. Bulashenko, L. L. Bonilla

Spatio-temporal chaos is predicted to occur in n-doped semiconductor superlattices with sequential resonant tunneling as their main charge transport mechanism. Under dc voltage bias, undamped time-dependent oscillations of the current (due to the motion and recycling of electric field domain walls) have been observed in recent experiments. Chaos is the resul

Matts Sporre

Statistical mechanics is used to study unrealizable generalization in two large feed-forward neural networks with binary weights and output, a perceptron and a tree committee machine. The student is trained by a teacher being larger, i.e. having more units than the student. It is shown that this is the same as using training data corrupted by Gaussian noise.

Reimer Kühn

An outline of Morita's equilibrium ensemble approach to disordered systems is given, and hitherto unnoticed relations to other, more conventional approaches in the theory of disordered systems are pointed out. It is demonstrated to constitute a generalization of the idea of grand ensembles and to be intimately related also to conventional low--concentrat

Jean-Philippe Bouchaud, Alain Comtet, Cécile Monthus

We analyze a simple dynamical model of glasses, based on the idea that each particle is trapped in a local potential well, which itself evolves due to hopping of neighbouring particles. The glass transition is signalled by the fact that the equilibrium distribution ceases to be normalisable, and dynamics becomes non-stationary. We generically find stretching

Andrew Gould, Douglas L. Welch

Optical/infrared photometry can double the number of proper motion measurements of Massive Compact Objects (MACHOs) relative to single band photometry. The proper motion of a MACHO can be measured by finding the ratio $q$ of the (known) radius of the source star to the Einstein radius of the MACHO, $q=θ_s/θ_e$. A classic method for doing this is to look for

David Woods, Gregory G. Fahlman, Harvey B. Richer

The number of close pairs of galaxies observed to faint magnitude limits, when compared to nearby samples, determines the interaction or merger rate as a function of redshift. The prevalence of mergers at intermediate redshifts is fundamental to understanding how galaxies evolve and the relative population of galaxy types. Mergers have been used to explain t

J. Richard Gott, III, Renyue Cen, Jeremiah P. Ostriker

The topology of large scale structure is studied as a function of galaxy type using the genus statistic. In hydrodynamical cosmological CDM simulations, galaxies form on caustic surfaces (Zeldovich pancakes) then slowly drain onto filaments and clusters. The earliest forming galaxies in the simulations (defined as ``ellipticals") are thus seen at the pre

Renyue Cen, Hyesung Kang, Jeremiah P. Ostriker, Dongsu Ryu

We present a new treatment of two popular models for the growth of structure, examining the X-ray emission from hot gas with allowance for spectral line emission from various atomic species, primarily ``metals". The X-ray emission from the bright cluster sources is not significantly changed from prior work and, as noted earlier, shows the CDM$+Λ$ model (

John D. Barrow, Paul Parsons

We examine inflationary universe models driven by scalar fields with logarithmic potentials of the form $V(ϕ) = V_0 ϕ^p(\ln ϕ)^q$. Combining the slow-roll approximation with asymptotic techniques, we identify regions of the potential where inflation may occur and obtain analytic expressions for the evolution of the field and the metric in these cases. We con

Uros Seljak

The Rees-Sciama (RS) effect produces fluctuations in the cosmic microwave background (CMB) through the time-dependent gravitational potential in the nonlinear stages of evolution. I investigate the RS effect on the CMB angular power spectrum $C_l$ for several CDM models by combining the results of N-body simulations with second order perturbation theory. The

A. M. Read, T. J. Ponman, R. D. Wolstencroft

We report the results of an X-ray spectral imaging observation of the Antennae with the ROSAT PSPC. 55% of the soft X-ray flux from the system is resolved into discrete sources, including components identified with the galactic nuclei and large HII regions, whilst the remainder appears to be predominantly genuinely diffuse emission from gas at a temperature

R. Silvotti, C. Bartolini, L. Stanghellini

A photoelectric monitoring program has been applied, during the last four years, to five central stars of planetary nebulae (PNNs) with strong O\,VI $λ$ 3811--34 Å\hspace{0.1mm} emission. NGC\,6905 and, marginally, NGC\,2452, show intrinsic luminosity variations, while NGC\,7026, IC\,2003 and NGC\,1501 have constant luminosity within a few mmag. Photometric

S. L. Lumsden, P. J. Puxley

Supernovae remnants are known to be luminous sources of infrared [FeII] emission. By studying how the luminosity scales with age, environment and other relevant factors, we can construct an [FeII] luminosity function for supernovae remnants. This will enable us to predict supernovae rates in starburst galaxies that are too distant for individual remnants to

J. Bryn Jones, Rosemary F. G. Wyse, Gerard Gilmore

Stellar spectra derived from current multiple-object fiber-fed spectroscopic radial-velocity surveys, of the type feasible with, among other examples, AUTOFIB, 2dF, HYDRA, NESSIE, and the Sloan survey, differ significantly from those traditionally used for determination of stellar abundances. The spectra tend to be of moderate resolution (around $1\,$Å) and

G. Parzen

The motion of a particle in 6-dimensional phase space in the presence of linear coupling can be written as the sum of 3 normal modes. A cubic equation is found for the tune of the normal modes, which allows the normal mode tunes to be computed from the 6x6 one turn transfer matrix. This result is similar to the quadratic equation found for the normal mode tu

Neta A. Bahcall, Lori M. Lubin, Victoria Dorman

How much dark matter is there in the universe and where is it located? These are two of the most fundamental questions in cosmology. We use in this paper optical and x-ray mass determinations of galaxies, groups, and clusters of galaxies to suggest that most of the dark matter may reside in very large halos around galaxies, typically extending to ~200 kpc fo

B. A. Brown, A. Csoto, R. Sherr

The relationship between the Coulomb displacement energy for the A=8, J=2+, T=1 state and the low-energy astrophysical S factor for the Be7(p,gamma)B8 reaction is discussed. The displacement energy is interpreted in a particle-hole model. The dependence of the particle displacement energy on the potential well geometry is investigated and is used to relate t

L. Cucurull, J. A. Grifols, R. Toldrà

We show how the $^4$He-abundance in the early Universe can be used to demonstrate that macroscopic samples of neutrinos in thermal equilibrium are indeed distributed according to Fermi-Dirac statistics.

Pavel Etingof, David Kazhdan

In the paper "On some unsolved problems in quantum group theory", V.Drinfeld formulated the problem of the existence of a universal quantization for Lie bialgebras. When the paper "Tensor structures arising from affine Lie algebras, III", by Kazhdan and Lusztig, appeared, Drinfeld asked whether its methods could be useful for the problem of u

G W Gibbons, D A Rasheed

We show that there is a function of one variable's worth of Lagrangians for a single Maxwell field coupled to gravity whose equations of motion admit electric-magnetic duality. Such Lagrangians are given by solutions of the Hamilton-Jacobi equation for timelike geodesics in Witten's two-dimensional black hole. Among them are the Born-Infeld Lagrangia

A. Dabelstein, W. Hollik, W. Moesle

A combined analysis for Z boson observables and the quantity Δr within the framework of the Minimal Supersymmetric Standard Model is presented. Contributions from supersymmetric particles are discussed and upper and lower bounds for the MSSM predictions are given.

J. D. Kim

We present a complete set of conjectures for the exact boundary reflection matrix for $ade$ affine Toda field theory defined on a half line with the Neumann boundary condition.

G. Eilam, I. Halperin, R. R. Mendel

We calculate to the leading twist 2 accuracy the rate for the decay $ B_{u} \rightarrow l νγ$ using the light cone QCD sume rules. We find $ Br( B_{u} \rightarrow l νγ) \simeq 2 \cdot 10^{-6} $. The results are used to test the applicability of the constituent quark model approximation to the same process.The latter estimate is proportional to $ 1/m_{u}^{2}

Lajos Diosi

According to Popescu's recent analysis [Phys. Rev. Lett. {\bf72}, 797 (1994)], {\it nonideal} measurements, rather than ideal ones, may be more sensitive to reveal nonlocal correlations between distant parts of composite quantum systems. The outcome statistics of joint nonideal measurements on local states should by definition admit local hidden variable

Robert Rałowski

This paper is on $C$ - symmetric creation and annihilation operators, which are constructed on Wick's algebras which fulfil consistency conditions. The essential assumption is that every algebraic action must be constant on equivalence classes. All consistency conditions follow from the above assumption. In this way we obtain well defined quotient algebr

Koichi Saito, Anthony W. Thomas

We emphasize that the composite structure of the nucleon may play quite an important role in nuclear physics. It is shown that the momentum-dependent repulsive force of second order in the scalar field, which plays an important role in Dirac phenomenology, can be found in the quark-meson coupling (QMC) model, and that the properties of nuclear matter are wel

Nathan Berkovits

In this talk, the new spacetime-supersymmetric description of the superstring is reviewed and some of its applications are described. These applications include the manifestly spacetime-supersymmetric calculation of scattering amplitudes, the construction of a super-Poincaré invariant open superstring field theory, and the beta-function calculation of low-en

N. Mohammedi, R. T. Moss, R. D. Simmons

The dual of the four dimensional non-linear sigma model is constructed using techniques familiar to string theory. This construction necessitates the introduction of a rank two antisymmetric tensor field whose properties are examined. The physics of the dual theory and that of the original model are compared. As an illustration we study in detail the SU(2) c

Kurt Lechner

The $κ$--anomaly cancellation mechanism in the heterotic superstring determines the superspace constraints for N=1, D=10 Supergravity--Super--Yang--Mills theory. We point out that the constraints found recently in this way appear to disagree with superspace solutions found in the past. We solve this puzzle establishing perfect agreement between the two metho

A. Gonzalez-Arroyo, Yu. A. Simonov

Dyonic classical solutions of Yang-Mills theory are considered and the complete set of fermionic zero modes of these solutions are studied. Representing the QCD vacuum as a gas of dyons, one obtains chiral symmetry breaking due to zero modes similarly to the case of instantonic vacuum.

P. Di Francesco, O. Golinelli, E. Guitter

The statistics of meander and related problems are studied as particular realizations of compact polymer chain foldings. This paper presents a general discussion of these topics, with a particular emphasis on three points: (i) the use of a direct recursive relation for building (semi) meanders (ii) the equivalence with a random matrix model (iii) the exact s

Satish D. Joglekar, Bhabani Prasad Mandal

In a superspace formulation of Yang-Mills theory previously proposed, we show how gauge-invariant operators and scalars can be incorporated keeping intact the (broken) $Osp(3,1|2)$ symmetry of the superspace action. We show in both cases, that the WT identities can be cast in a simple form $\frac{\partial\bar{W}}{\partialθ}=0$.

N. Kidonakis, J. Smith

The cross section for bottom quark production at fixed-target energies is calculated for a wide range of beam momenta. A detailed analysis is given for the HERA-B experiment. We consider both the order $α_s^3$ cross section and the resummation of soft gluon corrections in all orders of QCD perturbation theory. The inclusive transverse momentum and rapidity d

Yung Su Tsai

The $τ^\pm$, highly polarized in the direction of the incident beam, can be obtained from the $e^\pm$ collider with the polarized incident $e^-$ (and preferably also the $e^+$) beam. This polarization vector $\longvec w_i=(w_1+w_2)/(1+w_1w_2) \widehat e_z$ can be used to construct the $T$ odd rotationally invariant product $(\longvec w_i\times\longvec p_μ)$.

DIRK GRAUDENZ

We give an overview of jet physics in deeply inelastic scattering at HERA. The problem of jet definitions, the scale dependence of jet cross sections and some applications are discussed. (Talk presented at the Workshop on Deeply Inelastic Scattering and QCD, Paris, April 1995. To appear in the proceedings.)

A. Patkós

The consecutive integration over the distinct mass scales ${\cal O}(T),{\cal O}(gT)$ leads to a hierarchy of effective models for the electroweak phase transition. Different techniques for the realisation of such strategy are reviewed. Advantages and difficulties resulting from the use of reduced models are discussed.

A. Ali, V. M. Braun

The dominant long-distance contributions to the exclusive radiative decays $B \to ρ(ω) + γ$ involve photon emission from the light quarks at large distances, which cannot be treated perturbatively. We point out that this emission can be described in a theoretically consistent way as the magnetic excitation of quarks in the QCD vacuum and estimate the corresp

V. I. Nazaruk

We expose a grave drawback hidden in the standard model of neutron-antineutron transitions in a medium. Correcting it, one improves a limit on the free-space neutron-antineutron oscillation time by 31 orders of magnitude.

Alex Pomarol

Gauge and Yukawa (for the third family) coupling unification seem to be the best predictions of the grand-unified theories (GUTs). In supersymmetric GUTs, one also expects that the sparticle masses unify at the GUT scale (for sparticles embedded in the same GUT multiplet). I show under what circumstances GUTs do not lead to sparticle mass unification. In par

M. Braun

The triple pomeron interaction is studied in the perturbative approach of BFKL-Bartels. At finite momentum transfers $\sqrt{-t}$ the contribution factorizes in the standard manner with a triple-pomeron vertex proportional to $1/\sqrt{-t}$. At $t=0$ the contribution is finite, although it grows faster with energy than for finite $t$ and does not factorize.

Davison E. Soper, Levan R. Surguladze

We review the current status of the high order perturbative QCD evaluation of the hadronic decay rates of the Z and Higgs bosons. A systematic classification of the various types of QCD corrections to $O(α_s^2)$ and $O(α_s^3)$ is made and their numerical status is clarified.

David Atwood, Laura Reina, Amarjit Soni

Due to the very large mass of the top-quark, probing the flavor changing top-charm-scalar vertex is clearly very important. Fortunately the largeness of $m_t$ endows a unique signature to the resulting reaction i.e., $e^+e^-\to t\bar c (\bar t c)$ that should be helpful in identification of such events. A two Higgs doublet model, without natural flavor conse

A. Khodjamirian, G. Stoll, D. Wyler

We calculate the contribution of the weak annihilation to the $B\rightarrow ργ$ decay amplitude by means of QCD sum rules using the photon light-cone wave function. We find that this long-distance contribution amounts to about 10\% of the leading short-distance effect in $B^-\rightarrow ρ^-γ$. On the other hand, weak annihilation is the dominant source of th

Carl M. Bender, Stefan Boettcher, Peter N. Meisinger

Models of random walks are considered in which walkers are born at one location and die at all other locations with uniform death rate. Steady-state distributions of random walkers exhibit dimensionally dependent critical behavior as a function of the birth rate. Exact analytical results for a hyperspherical lattice yield a second-order phase transition with

Carl M. Bender, Peter N. Meisinger, Stefan Boettcher

A recently developed model of random walks on a $D$-dimensional hyperspherical lattice, where $D$ is {\sl not} restricted to integer values, is used to study polymer growth near a $D$-dimensional attractive hyperspherical boundary. The model determines the fraction $P(κ)$ of the polymer adsorbed on this boundary as a function of the attractive potential $κ$

Carl M. Bender, Peter N. Meisinger, Stefan Boettcher

A recently developed model of random walks on a $D$-dimensional hyperspherical lattice, where $D$ is {\sl not} restricted to integer values, is extended to include the possibility of creating and annihilating random walkers. Steady-state distributions of random walkers are obtained for all dimensions $D>0$ by solving a discrete eigenvalue problem. These dist

Carl M. Bender, Peter N. Meisinger, Fred Cooper

Spherically symmetric random walks in arbitrary dimension $D$ can be described in terms of Gegenbauer (ultraspherical) polynomials. For example, Legendre polynomials can be used to represent the special case of two-dimensional spherically symmetric random walks. In general, there is a connection between orthogonal polynomials and semibounded one-dimensional

The SLD Collaboration

A measurement of the lifetime of the tau lepton has been made using a sample of 1671 $Z^0\rightarrowτ^+τ^-$ decays collected by the SLD detector at SLC. The measurement benefits from the small and stable collision region at SLC and the precision vertex detector of SLD. Three analysis techniques have been used: decay length, impact parameter, and impact param

Giampiero Esposito, Cosimo Stornaiolo

A recent analysis of real general relativity based on multisymplectic techniques has shown that boundary terms may occur in the constraint equations, unless some boundary conditions are imposed. This paper studies the corresponding form of such boundary terms in complex general relativity, where space-time is a four-complex-dimensional complex-Riemannian man

B. Linet

Within the framework of the quantum field theory at finite temperature on a conical space, we determine the Euclidean thermal spinor Green's function for a massless spinor field. We then calculate the thermal average of the energy-momentum tensor of a thermal bath of massless fermions. In the high-temperature limit, we find that the straight cosmic strin

D. Senechal

The Heisenberg spin ladder is studied in the semiclassical limit, via a mapping to the nonlinear $σ$ model. Different treatments are needed if the inter-chain coupling $K$ is small, intermediate or large. For intermediate coupling a single nonlinear $σ$ model is used for the ladder. Its predicts a spin gap for all nonzero values of $K$ if the sum $s+\tilde s

P. A. Rikvold, J. Zhang, Y. -E. Sung, A. Wieckowski

The theory of statistical-mechanical lattice-gas modeling of adsorption is reviewed and shown to be applicable to a range of electrochemical problems dominated by effective, lateral adsorbate--adsorbate interactions. A general strategy for applying the method to specific systems is outlined, which includes microscopic model formulation, calculation of zero-t

Alain COMTET, Cecile MONTHUS

Classical diffusion in a random medium involves an exponential functional of Brownian motion. This functional also appears in the study of Brownian diffusion on a Riemann surface of constant negative curvature. We analyse in detail this relationship and study various distributions using stochastic calculus and functional integration.

Cecile MONTHUS

This article deals with transport properties of one dimensional Brownian diffusion under the influence of a correlated quenched random force, distributed as a two-level Poisson process. We find in particular that large time scaling laws of the position of the Brownian particle are analogous to the uncorrelated case. We discuss also the probability distributi

Jongbae Hong, Hae-Young Kee

We show that the analytic single-particle density of states and the optical conductivity for the half-filled Hubbard model on the Bethe lattice in infinite dimensions describe quantitatively the behavior of the gap and the kinetic energy ratio of the correlated insulator $V_2O_3$. The form of the optical conductivity shows $ω^{3/2}$ rising and is quite simil

Seth Kulick

Many theories of semantic interpretation use lambda-term manipulation to compositionally compute the meaning of a sentence. These theories are usually implemented in a language such as Prolog that can simulate lambda-term operations with first-order unification. However, for some interesting cases, such as a Combinatory Categorial Grammar account of coordina

G. Gentile, V. Mastropietro

This paper consists in a unified exposition of methods and techniques of the renormalization group approach to quantum field theory applied to classical mechanics, and in a review of results: (1) a proof of the KAM theorem, by studing the perturbative expansion (Lindstedt series) for the formal solution of the equations of motion; (2) a proof of a conjecture

M. A. Pahre, S. G. Djorgovski

We present the first results from a near-infrared narrow-band search for primeval galaxies (PGs) using the Keck 10~m telescope. We have targeted our fields for three QSOs and one radio galaxy at redshifts $z = 2.28$ to $4.70$. We selected narrow-band filters in the $K$-band centered on strong emision lines at the redshift of the targets. We reach limiting fl

Patrick Cote, Douglas L. Welch, Philippe Fischer, K. Gebhardt

B,V CCD frames have been used to derive surface brightness profiles for NGC 3201 out to ~18 arcmin. A total of 857 radial velocities with median precision ~1 km/s for 399 member giants have been used to trace the velocity dispersion profile out to 32' (the approximate tidal radius from fits of single-mass, isotropic King-Michie models to the cluster surf

R. J. Ivison

A search for millimetric continuum emission from eight optically-selected, radio-quiet quasars and a radiogalaxy with 3.7 < z < 4.3, has been undertaken using a highly sensitive 7-channel bolometer on the IRAM 30-m Millimetre Radio Telescope. Detections of a potentially dust-rich quasar, and of 8C1435+635, the most distant known radiogalaxy, are reported. An

W. D. Cotton, L. Feretti, G. Giovannini, T. Venturi

We present observations at 1.7 and 8.4 GHz of two Compact Steep Spectrum (CSS) sources from a complete sample of low-intermediate power radio galaxies. 3C346 shows an asymmetric structure with a one-sided ``jet&#39;&#39; and ``hot spot&#39;&#39;. Present observations suggest that the classification of this source as a CSS is inappropriate, and that it is a c

Pavel Kroupa

We introduce a model Galactic field low-mass stellar population that has a proportion of binary systems as observed, with a mass ratio distribution consistent with observational constraints. The model single star and system luminosity function agrees with the nearby and the Malmquist corrected photometric luminosity function, respectively. We tabulate the mo

S. W. Allen, A. C. Fabian, J. P. Kneib

We present spatially-resolved X-ray spectroscopy of the X-ray luminous cluster of galaxies, PKS0745-191, using observations made with the ASCA and ROSAT satellites. The X-ray data measure the density, temperature, and metallicity profiles of the cluster gas and constrain the distribution of mass in the cluster to a radius of \sim 1.5 Mpc. We report the disco

Boris E. Stern, Juri Poutanen, Roland Svensson, Marek Sikora

For the first time, detailed radiative transfer calculations of Comptonized X-ray and gamma-ray radiation in a hot pair plasma above a cold accretion disk are performed using two independent codes and methods. The simulations include both energy and pair balance as well as reprocessing of the X- and gamma-rays by the cold disk. We study both plane-parallel c

G. Giovannini, W. D. Cotton, L. Feretti, L. Lara

The parsec scale properties of low power radio galaxies are reviewed here, using the available data on 12 FR I galaxies. The most frequent radio structure is an asymmetric parsec-scale morphology, i.e. core and one-sided jet. It is shared by 9 (possibly 10) of the 12 mapped radio galaxies. One (possibly 2) of the other galaxies has (have) a two-sided jet emi

Garrelt Mellema

This paper reports the results of the numerical study of the formation of aspherical Planetary Nebulae through the Generalised Interacting Winds Model, taking into account the effects caused by the evolving central star and fast wind. The results show for the first time that aspherical nebulae do form within the required time scale. Consideration of the deve

Jochen Heidt, Stefan J. Wagner

We present a study of the intraday variability behaviour of a complete sample of radio-selected BL Lac objects taken from the 1 Jy catalogue. In 28 out of 34 BL Lac objects (82\%) we detected intraday variability. 7 objects were observed during several campaigns. None of them changed its variability behaviour. The duty cycle in radio-loud BL Lac objects is v

Naoteru Gouda

The pseudo-spectral method is proposed for following the evolution of density and velocity fluctuations at the weakly non-linear stage in the expanding universe with a good accuracy. In this method, the evolution of density and velocity fluctuations is integrated in the Fourier Space with using FFT. This method is very useful to investigate accurately the no

Jose&#39; Felipe Voloch

A singular curve over a non-perfect field K may not have a smooth model over K. Those are said to &#34;change genus&#34;. If K is a global field of positive characteristic and C/K a curve that change genus, then C(K) is known to be finite. The purpose of this note is to give examples of curves with fixed relative genus, defined over K for which #C(K) is arbi

Barbara Drossel

Depending on the rule for tree growth, the forest-fire model shows either self-organized criticality with rule-dependent exponents, or synchronization, or an intermediate behavior. This is shown analytically for the one-dimensional system, but holds evidently also in higher dimensions.

Nemanja Kaloper, Richard Madden, Keith A. Olive

We consider the problem of constructing a non-singular inflationary universe in stringy gravity via branch changing, from a previously superexponentially expanding phase to an FRW-like phase. Our approach is based on the phase space analysis of the dynamics, and we obtain a no-go theorem which rules out the efficient scenario of branch changing catalyzed by

Edward Frenkel

We review various aspects of representation theory of affine algebras at the critical level, geometric Langlands correspondence, and Bethe ansatz in the Gaudin models. Geometric Langlands correspondence relates D-modules on the moduli space of G-bundles on a complex curve X and flat G^L-bundles on X. Beilinson and Drinfeld construct it by applying a localiza

M. N. Chernodub, F. V. Gubarev

We show that the instantons induce the abelian monopoles in the Maximal Abelian Projection of $SU(2)$ gluodynamics. As an example we consider the case of one instanton and the case of a set of instantons arranged along a straight line. The abelian monopoles which are induced by instantons may play some role in the confinement scenario.

F. J. de Urries, J. Julve

As an example of what happens with physically relevant theories like effective gravity, we consider the covariant relativistic theory of a scalar field of arbitrarily higher differential order. A procedure based on the Legendre transformation and suitable field redefinitions allows to recast it as a theory of second order with one explicit independent field

K. Sumiyoshi, H. Suzuki, H. Toki

We study the influence of the symmetry energy of the equation of state on the thermal evolution of protoneutron stars and the properties of supernova neutrinos by the numerical simulations after the protoneutron stars are formed. As for the equation of state (EOS) of nuclear matter, we take two EOS&#39;s with different symmetry energies obtained by the relat

W. Czyż, J. Turnau

We propose a new type of the measurement which is sensitive to the QCD vacuum color-magnetic fluctuations: A measure of the axial assymetry of the hadronic final states produced in the high energy $e^{+}e^{-}$ collisions is related to the chromomagnetic vacuum field strength.

B. Bacus, Y. Meurice, A. Soemadi

Using an ansatz motivated by the classical form of $e^{iϕ}$, where $ϕ$ is the angle variable, we construct operators which satisfy the commutation relations of the creation-annihilation operators for the anharmonic oscillator. The matrix elements of these operators can be expressed in terms of {\it entire} functions in the position complex plane. These funct

S. Kuyucak, S. C. Li

We use the 1/$N$ expansion formalism in a systematic study of high-spin states in the $sd$ and $sdg$ boson models with emphasis on spin dependence of moment of inertia and E2 transitions. The results are applied to the high-spin states in the actinide nuclei $^{232}$Th, $^{234-238}$U, where the need for $g$ bosons is especially acute but until now, no realis

Burt A. Ovrut

A discussion of the number of degrees of freedom, and their dynamical properties, in higher derivative gravitational theories is presented. It is shown that non-vanishing $(C_{mnpq})^{2}$ terms arise in N=1, D=4 superstring Lagrangians due to one-loop radiative corrections with light field internal lines.

J. E. Paschalis, P. I. Porfyriadis

The three-flavour Wess-Zumino model coupled to electromagnetism is treated as a constraint system using the Faddeev-Jackiw method. Expanding into series of powers of the Goldstone boson fields and keeping terms up to second and third order we obtain Coulomb-gauge hamiltonian densities.

Manuel Drees, Rohini M. Godbole

We propose a modification of the equivalent photon approximation (EPA) for processes which involve the parton content of the photon, to take into account the suppression of the photonic parton fluxes due to the virtuality of the photon. We present simple, physically motivated ansätze to model this suppression and show that even though the parton content of t

Simonetta Liuti, Franz Gross

We study the nuclear ($A$) dependence of the European Muon Collaboration (EMC) effect at high values of $x$ ($x \geq 0.6$). Our approach makes use of conventional nuclear degrees of freedom within the Relativistic Impulse Approximation. By performing a non-relativistic series expansion we demonstrate that relativistic corrections make a substantial contribut

D. Zeppenfeld

A direct measurement of the trilinear $WW\gamma$ and $WWZ$ couplings is possible in the pair production of electroweak bosons at $e^+e^-$ and hadron colliders. This talk addresses some of the theoretical issues: the parameterization of ``anomalous couplings'' in terms of form factors and effective Lagrangians, the complementary information which can be obtai

J. -F. Zhang, Nimai C. Mukhopadhyay, M. Benmerrouche

We examine eta prime photoproduction, as a novel tool to study baryon resonances around 2 GeV, of particular interest to the quark shell model, which predicts a number of them. We find important roles of the form factors at the strong vertices, and show that the N^*(2080) can be probed efficiently by this reaction.

A. A. Bel&#39;kov, A. V. Lanyov, A. Schaale

The calculation of heat-kernel coefficients with the classical DeWitt algorithm has been discussed. We present the explicit form of the coefficients up to $h_5$ in the general case and up to $h_7^{min}$ for the minimal parts. The results are compared with the expressions in other papers. A method to optimize the usage of memory for working with large express

M. R. Ahmady, D. Liu, A. H. Fariborz

Short and long distance contributions to the exclusive B-decays into various K-resonances and dileptons, i.e. B --> Ki l l ( l = e, mu , nu ), are examined. The heavy quark effective theory has been used to calculate the hadronic matrix elements. Substantial branching fractions are obtained for the dileptonic B-decays into some higher excited states of K-mes

P. K. Coyle, I. G. Halliday

A cluster algorithm is presented for the $Z_2$ Kalb-Ramond plaquette model in four dimensions which dramatically reduces critical slowing. The critical exponent $z$ is reduced from $ z>2$ (standard Metropolis algorithm) to $z= 0.32\pm0.06$. The Cluster algorithm updates the monopole configuration known to be responsible for the second order phase transition.

P. Lacock, C. Michael

We analyse the meson spectrum in quenched QCD using lattice gauge theory. By studying hadron propagation with a variety of operators (both smeared and local), we are able to extract the ground state and first excited state masses with confidence. We pay attention to the correlations among the data used in the fits to extract these masses and couplings. We co

J. Skarha

We present recent CDF results on $B$ lifetimes, $B$ meson mass measurements, ratios of branching ratios, and rare decays. In addition, we present the first measurement of time-dependent $B_d$ mixing at CDF. Several results have been updated and a few new ones included since the workshop.

H1 Collaboration

The cross sections for the charged current processes ${e^{-}p}\rightarrow{ν_e+hadrons}$ and, for the first time, ${e^{+}p}\rightarrow{\overlineν_e+hadrons}$ are measured at HERA for transverse momenta larger than 25 GeV.

L. P. Grishchuk

In a recent paper, Parker and Zhang [1] consider cosmological perturbations that can be possibly produced in the early Universe. This is an interesting problem having important observational implications. The paper of Parker and Zhang is transparent and honest, in the sense that the authors clearly identify what they derive and what they use from the previou

G. Esposito, C. Stornaiolo, G. Gionti

The Lagrangian formulation of classical field theories and in particular general relativity leads to a coordinate-free, fully covariant analysis of these constrained systems. This paper applies multisymplectic techniques to obtain the analysis of Palatini and self-dual gravity theories as constrained systems, which have been studied so far in the Hamiltonian

Ingemar Bengtsson

Once the action for Einstein&#39;s equations is rewritten as a functional of an SO(3,C) connection and a conformal factor of the metric, it admits a family of ``neighbours&#39;&#39; having the same number of degrees of freedom and a precisely defined metric tensor. This paper analyzes the relation between the Riemann tensor of that metric and the curvature t