January 1999 arXiv papers — page 6

Yoshiaki Taniguchi, Satoru, Ikeuchi, Yasuhiro Shioya

We investigate whether or not a supermassive black hole (SMBH) with mass $\gtrsim 10^8 M_\odot$ can be made in the heart of ultraluminous infrared galaxies (ULIGs) during the course of mergers between/among gas rich galaxies. (a) If one progenitor galaxy had a seed SMBH with mass of $\sim 10^7 M_\odot$, this seed SMBH can grow up to $\gtrsim 10^8 M_\odot$ du

K. Heinemann, D. P. Barber

We show how, beginning with the Fokker--Planck equation for electrons emitting synchrotron radiation in a storage ring, the corresponding equation for spin motion can be constructed. This is an equation of the Bloch type for the polarisation density.

S. M. Gerasyuta, V. I. Kochkin

The four-quark equations are found in the framework of the dispersion relation technique. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitudes are obtained. The four-quark amplitudes of cryptoexotic mesons including the quarks of three flavours (u, d, s) are calculated. The mass valu

A. Borde, H. F. Dowker, R. S. Garcia, R. D. Sorkin

A change of spatial topology in a causal, compact spacetime cannot occur when the metric is globally Lorentzian. One can however construct a causal metric from a Riemannian metric and a Morse function on the background cobordism manifold, which is Lorentzian almost everywhere except that it is degenerate at each critical point of the function. We investigate

Joseph E. Avron, Zvi Kons

We show that the response to an electric field, in models of the Integral Quantum Hall effect, is analytic in the field and has isolated essential singularity at zero field. We also study the breakdown of Chern numbers associated with the response of Floquet states. We argue, and give evidence, that the breakdown of Chern numbers in Floquet states is a disco

Ulf-G. Meissner, A. Rakhimov, U. Yakhshiev

We investigate an extended chiral soliton model which includes $π, ρ, ω$ and $σ$ mesons as explicit degrees of freedom. The Lagrangian incorporates chiral symmetry and broken scale invariance. A scalar-isoscalar meson $σ$ is associated with a quarkonium dilaton field with a mass $\msig\approx 550 $MeV. We show that the scalar field with anomalous dimension s

Nuno D. Antunes, Luis M. A. Bettencourt, Andrew Yates

O(N) symmetric $λϕ^4$ field theories describe many critical phenomena in the laboratory and in the early Universe. Given N and $D\leq 3$, the dimension of space, these models exhibit topological defect classical solutions that in some cases fully determine their critical behavior. For N=2, D=3 it has been observed that the defect density is seemingly a unive

Fritz Gesztesy, Helge Holden

We systematically study Darboux-type transformations for the KdV and AKNS hierarchies and provide a complete account of their effects on hyperelliptic curves associated with algebro-geometric solutions of these hierarchies.

K. Heinemann, D. P. Barber

A semiclassical Foldy--Wouthuysen transformation of the Dirac equation is used to obtain the radiationless Bloch equation for the polarisation density.

D. P. Barber

The relationship between the level of spin polarisation caused by Unruh radiation as calculated by Bell and Leinaas and that obtained from the Derbenev-Kondratenko formalism is explained.

D. P. Barber, K. Heinemann, G. H. Hoffstaetter, M. Vogt

We illustrate the use of the invariant spin field for describing permissible equilibrium spin distributions in high energy spin polarised proton beams.}

D. P. Barber

The first attainment of longitudinal spin polarisation in a high energy electron (positron) storage ring is described.

D. P. Barber

I review recent developments in spin dynamics in electron storage rings and accelerators.

Zbigniew Hasiewicz, Zbigniew Jaskolski, Andrzej Ostrowski

The covariant operator quantization of the ordinary free spinning BDH string modified by adding the supersymmetric Liouville sector is analysed in the even target space dimensions $d=2,4,6,8$. The spectrum generating algebra for this model is constructed and a general version of the no-ghost theorem is proven. A counterpart of the GSO projection leads to a f

S. Hollands, M. Mueller-Preussker

A geometric definition for a magnetic charge of Abelian monopoles in SU(N) lattice gauge theories with Higgs fields is presented. The corresponding local monopole number defined for almost all field configurations does not require gauge fixing and is stable against small perturbations. Its topological content is that of a 3-cochain. A detailed prescription f

B. G. Konopelchenko, G. Landolfi

Generalized Weierstrass formulae for surfaces in four-dimensional space $\Bbb{R}^{4}$ are used to study (anti)self-dual rigid string configurations. It is shown that such configurations are given by superminimal immersions into $\Bbb{R}^{4}$. Explicit formulae for generic (anti)instantons are presented. Particular classes of surfaces are also analyzed.

Vladimir O. Soloviev

It is shown that the Poisson bracket with boundary terms recently proposed by Bering (hep-th/9806249) can be deduced from the Poisson bracket proposed by the present author (hep-th/9305133) if one omits terms free of Euler-Lagrange derivatives ("annihilation principle"). This corresponds to another definition of the formal product of distributions (o

P. K. Townsend

I review a recently proposed method for determining the symmetry superalgebra of a supergravity configuration from its Killing spinors, and its application to the `near-horizon' limits of various rotating and intersecting branes.

B. Schroer, H. -W. Wiesbrock

In thermal states of chiral theories, as recently investigated by H.-J. Borchers and J. Yngvason, there exists a rich group of hidden symmetries. Here we show that this leads to a radical converse of of the Hawking-Unruh observation in the following sense. The algebraic commutant of the algebra associated with a (heat bath) thermal chiral system can be used

Michael Dine, Robert Echols, Joshua P. Gray

It has recently been shown that the Matrix model and supergravity give the same predictions for three graviton scattering. This contradicts an earlier claim in the literature (hep-th/9710174). We explain the error in this earlier work, and go on to show that certain terms in the $n$-graviton scattering amplitude involving $v^{2n}$ are given correctly by the

Jun-Chen Su

It is argued that the massive non-Abelian gauge field theory without involving Higgs bosons may be well established on the basis of gauge-invariance principle because the dynamics of the field is gauge-invariant in the physical space defined by the Lorentz constraint condition. The quantization of the field can readily be performed in the Hamiltonian path-in

Jun-chen Su

According to the conventional concept of the gauge field theory, the local gauge invariance excludes the possibility of giving a mass to the gauge boson without resorting to the Higgs mechanism because the Lagrangian constructed by adding a mass term to the Yang-Mills Lagrangian is not only gauge-non-invariant, but also unrenormalizable. On the contrary, we

German Rodrigo, Arcadi Santamaria, Mikhail Bilenky

Next-to-leading order calculations of heavy quark three-jet production in e^+ e^- annihilation are reviewed. Their application for the measurement of the b-quark mass at LEP/SLC and to the test of the flavour independence of the strong coupling constant are discussed. Prospects for future improvements are studied.

Luis Bento

It is shown that true Nambu-Goldstone (NG) bosons develop coherent fields whenever the associated charges of the matter particles are not conserved in a macroscopic scale. The sources of the NG fields are the time rates of quantum number violation. If the lepton numbers are spontaneously broken at a scale below 1 TeV, the neutrino oscillation processes gener

Shinsuke Kawai, Masa-aki Sakagami, Jiro Soda

A stability analysis is made for a non-singular pre-big-bang like cosmological model based on 1-loop corrected string effective action. Its homogeneous and isotropic solution realizes non-singular transition from de Sitter universe to Friedmann-like universe, via super inflation phase. We are interested in whether the non-singular nature of the solution woul

Ruggiero de Ritis, Giuseppe Marmo, Bruno Preziosi

A free system, considered to be a comparison system, allows for the notion of objective existence and inertial frame. Transformations connecting inertial frames are shown to be either Lorentz or generalized Galilei.

Barry M. Leiner, Vinton G. Cerf, David D. Clark, Robert E. Kahn

The Internet has revolutionized the computer and communications world like nothing before. The invention of the telegraph, telephone, radio, and computer set the stage for this unprecedented integration of capabilities. The Internet is at once a world-wide broadcasting capability, a mechanism for information dissemination, and a medium for collaboration and

H. Won, H. Jang, K. Maki

We study theoretically the paramagnetic state in d-wave superconductors. We present the specific heat, the magnetization, superfluid density obtained within the weak-coupling model. At low temperatures and for small magnetic fields they exhibit simple power law behaviors, which should be accessible experimentally in hole-doped high-T_c cuprates and κ-(ET)_2

Leonid B. Litinskii

The set of the fixed points of the Hopfield type network is under investigation. The connection matrix of the network is constructed according the Hebb rule from the set of memorized patterns which are treated as distorted copies of the standard-vector. It is found that the dependence of the set of the fixed points on the value of the distortion parameter ca

Sorin Solomon

This is a pedagogical review of the the Generalized Lotka-Volterra (GLV) model: w_i(t+1) = lambda * w_i(t) + a * W (t) - c * W (t) * w_i(t) where i=1, >......, N and W= (w_1 + w_2 + ...w_N)/N is the average of the w_i's. The GLV models provide a generic method to simulate, analyze and understand a wide class of phenomena which are characterized by (trunc

A. Knigavko, B. Rosenstein, Y. F. Chen

Complete topological classification of solutions in SO(3) symmetric Ginzburg-Landau free energy has been performed and a new class of solutions in weak external magnetic field carrying two units of magnetic flux has been identified. These solutions, magnetic skyrmions, do not have singular core like Abrikosov vortices and at low magnetic field become lighter

Ramon Reigada, Aldo H. Romero, Katja Lindenberg, Jose M. Sancho

The time-dependent transmission coefficient for the Kramers problem exhibits different behaviors in different parameter regimes. In the high friction regime it decays monotonically ("non-adiabatic"), and in the low friction regime it decays in an oscillatory fashion ("energy-diffusion-limited"). The generalized Kramers problem with an exponen

R. Movshovich, M. Jaime, S. Mentink, A. A. Menovsky

Hexagonal UNi_4B is magnetically frustrated, yet it orders antiferromagnetically at T_N = 20 K. However, one third of the U-spins remain paramagnetic below this temperature. In order to track these spins to lower temperature, we measured the specific heat C of \unib between 100 mK and 2 K, and in applied fields up to 9 T. For zero field there is a sharp kink

E. Balkovsky, G. Falkovich, V. Lebedev, M. Lysiansky

We consider statistics of the passive scalar on distances much larger than the pumping scale. Such statistics is determined by statistics of Lagrangian contraction that is by probabilities of initially distant fluid particles to come close. At the Batchelor limit of spatially smooth velocity, the breakdown of scale invariance is established for scalar statis

L. M. Macri, J. P. Huchra, P. B. Stetson, N. A. Silbermann

We report on the discovery of Cepheids in the Virgo spiral galaxy NGC 4535, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. NGC 4535 is one of 18 galaxies observed as a part of The HST Key Project on the Extragalactic Distance Scale which aims to measure the Hubble constant to 10% accuracy. NGC 4535

K. Z. Stanek, J. Kaluzny, M. Krockenberger, D. D. Sasselov

We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33 -- using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photo

D. Kranich, R. Mirzoyan, D. Petry, B. C. Raubenheimer

TeV Gamma-ray signals from the Crab Nebula and Mkn 501 were detected with the HEGRA CT1 imaging Cerenkov telescope during periods when the moon was shining and during twilight. This was accomplished by lowering the high voltage supply of the photomutipliers in fixed steps up to 13%. No other adjustments were made and no filters were used. Laser runs could no

A. S. Wilson, J. C. Raymond

We consider a model in which the narrow line regions (NLRs) of Seyfert galaxies are photoionized ``in situ'' by fast (300 -- 1,000 km/s), radiative shock waves driven into the interstellar medium of the galaxy by radio jets from the active nucleus. Such shocks are powerful sources of soft X-rays. We compute the expected ratio of the count rates in th

Sorin Solomon

The price fluctuations in the financial markets are the result of the individual operations by many individual investors. However for many decades the finacial theory did not use directly this "microscopic representation". The difficulties preventing it were multiple but the main two are being solved recently with the advent of modern computer techno

Thomas Mehen, Iain W. Stewart

For interactions involving two or more nucleons it is useful to divide pions into three classes: potential, radiation, and soft. The momentum threshold for the production of radiation pions is $Q_r = \sqrt{M_N m_π}$. We show that radiation pions can be included systematically with a power counting in $Q_r$. The leading order radiation pion graphs which contr

G. Dvali, M. Shifman

In supersymmetric models with the run-away vacua or with the stable but non-supersymmetric ground state there exist stable field configurations (vacua) which restore one half of supersymmetry and are characterized by constant positive energy density. The formal foundation for such vacua is provided by the central extension of the N =1 superalgebra with the i

D. J. Pisano, Eric M. Wilcots

We have used the VLA to search for gaseous remnants of the galaxy formation process around six extremely isolated galaxies. We found two distinct HI clouds around each of two galaxies in our sample (UGC 9762 & UGC 11124). These clouds are rotating and appear to have optical counterparts, strongly implying that they are typical dwarf galaxies. The companions

D. A. Demir

By using the effective potential approximation and taking into account the dominant top quark and scalar top quark loops, radiative corrections to MSSM Higgs potential are computed in the presence of the supersymmetric CP-violating phases. It is found that, the lightest Higgs scalar remains essentially CP-even as in the CP-invariant theory whereas the other

S. Aoki, M. Fukugita, S. Hashimoto, N. Ishizuka

A lattice QCD calculation of the kaon $B$ parameter $B_K$ is carried out with the Wilson quark action in the quenched approximation at $β=6/g^2=5.9-6.5$. The mixing problem of the $Δs=2$ four-quark operators is solved non-perturbatively with full use of chiral Ward identities employing four external quarks with an equal off-shell momentum in the Landau gauge

V. Barger, Yuan-Ben Dai, K. Whisnant, Bing-Lin Young

We examine the prospects for determining the neutrino mixing matrix and for observing CP and T violation in neutrino oscillations in four-neutrino models. We focus on a general class of four-neutrino models with two pairs of nearly degenerate mass eigenstates separated by approximately 1 eV, which can describe the solar, atmospheric and LSND neutrino data. W

Ph. Ghosez, E. Cockayne, U. V. Waghmare, K. M. Rabe

The full phonon dispersion relations of lead titanate and lead zirconate in the cubic perovskite structure are computed using first-principles variational density-functional perturbation theory, with ab initio pseudopotentials and a plane-wave basis set. Comparison with the results previously obtained for barium titanate shows that the change of a single con

Thomas Appelquist, Andrew G. Cohen, Martin Schmaltz

We propose a new constraint on the structure of strongly coupled field theories. The constraint takes the form of an inequality limiting the number of degrees of freedom in the infrared description of a theory relative to the number of underlying, ultraviolet degrees of freedom. We apply the inequality to a variety of theories (both supersymmetric and nonsup

TARO Collaboration, Ph. de Forcrand, M. Garcia Perez, T. Hashimoto

We analyze temporal and spatial meson correlators in quenched lattice QCD at T>0. Above T_c we find different masses and (spatial) screening masses, signals of plasma formation, and indication of persisting mesonic excitations.

Dominic Clancy, Alexander Feinstein, James E. Lidsey, Reza Tavakol

Families of anisotropic and inhomogeneous string cosmologies containing non-trivial dilaton and axion fields are derived by applying the global symmetries of the string effective action to a generalized Einstein-Rosen metric. The models exhibit a two-dimensional group of Abelian isometries. In particular, two classes of exact solutions are found that represe

J. Charles, A. Le Yaouanc, L. Oliver, O. Pène

We prove the full covariance of the heavy-to-light weak current matrix elements based on the Bakamjian-Thomas construction of relativistic quark models, in the heavy mass limit for the parent hadron and the large energy limit for the daughter one. Moreover, this quark model representation of the heavy-to-light form factors fulfills the general relations that

James V. Steele, Ismail Zahed

Electromagnetic emission rates from a thermalized hadronic gas are important for the interpretation of dilepton signals from heavy-ion collisions. Although there is a consensus in the literature about rates for a pure meson gas, qualitative differences appear with a finite baryon density. We show this to be essentially due to the way in which the pi-N backgr

Alex Hansen, Mogens H. Jensen, Kim Sneppen, Giovanni Zocchi

We propose a model for motor proteins based on a hierarchical Hamiltonian that we have previously introduced to describe protein folding. The proposed motor model has high efficiency and is consistent with a linear load-velocity response. The main improvement with respect to previous models is that this description suggests a connection between folding and f

N. N. Achasov, G. N. Shestakov

It is shown that the list of unusual mesons planned for a careful study in photoproduction can be extended by the exotic states $X^\pm(1600)$ with $I^G(J ^{PC})=2^+(2^{++})$ which should be looked for in the $ρ^\pmρ^0$ decay channels in the reactions $γN\toρ^\pmρ^0N$ and $γN\toρ^\pm ρ^0Δ$. The full classification of the $ρ^\pmρ^0$ states by their quantum num

K. Bennaceur, F. Nowacki, J. Okolowicz, M. Ploszajczak

We apply the realistic shell model which includes the coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states to the spectroscopy of mirror nuclei: $^8$B and $^8$Li, as well as to the description of low energy cross sections (the astrophysical S factors) in the capture reactions:$^7Be(p,γ)^8B$ and $^7Li(n,γ)^8L

K. Zarembo

The low-energy theory on the world volume of parallel static D3-branes of type 0 strings is the Yang-Mills theory with six scalar fields in the adjoint representation. One-loop corrections in this theory induce Coleman-Weinberg effective potential, which can be interpreted as an interaction energy of D3-branes. The potential is repulsive at short distances a

Seungjoon Hyun, Youngjai Kiem, Hyeonjoon Shin

Membrane source-probe dynamics is investigated in the framework of the finite N-sector DLCQ M theory compactified on a transverse two-torus for an arbitrary size of the longitudinal dimension. The non-perturbative two fermion terms in the effective action of the matrix theory, the (2+1)-dimensional supersymmetric Yang-Mills theory, that are related to the fo

G. P. Rowell, S. A. Dazeley, P. G. Edwards, S. Gunji

We have searched for TeV gamma-rays from Centaurus A and surrounding region out to +/- 1.0 deg using the CANGAROO 3.8m telescope. No evidence for TeV gamma-ray emission was observed from the search region, which includes a number of interesting features located away from the tracking centre of our data. The 3 sigma upper limit to the flux of gamma-rays above

Chanyong Park, Sang-Jin Sin

We study the cosmology of the Brans-Dicke theory with perfect fluid type matter. In our previous work, we found exact solutions for any Brans-Dicke parameter $ω$ and for general parameter $γ$ of equation of state. In this paper we further study the cosmology of these solutions by analyzing them according to their asymptotic behaviors. The cosmology is classi

H. N. Bachman, V. F. Mitrovi{ć}, A. P. Reyes, W. P. Halperin

The electronic spin susceptibility of YBa_2Cu_3O_{6.95} has been measured with high precision up to 24 Tesla with 17O nuclear magnetic resonance. Its temperature dependence can be accounted for by superconducting fluctuations that result in a smooth crossover from the normal to the vortex liquid state. A magnetic field-temperature phase diagram for this cros

D. P. Barber

This article provides a unified introduction to the theory of electron and proton spin polarisation in storage rings and it provides a common starting point for the written versions of the four talks that I gave at Monterey

Igor P. Omelyan

A computer adapted theory for self-consistent calculations of the wavevector- and frequency-dependent dielectric constant for interaction site models of polar systems is proposed. A longitudinal component of the dielectric constant is evaluated for the TIP4P water model in a very wide scale of wavenumbers and frequencies using molecular dynamics simulations.

C. Bennhold, T. Mart, A. Waluyo, H. Haberzettl

Nucleon resonances are investigated through the electromagnetic production of K-mesons. We study the kaon photoproduction process at tree-level and compare to a recently developed unitary K-matrix approach. Employing hadronic form factors along with the proper gauge prescription yields suppression of the Born terms and leads a resonance dominated process for

Thomas D. Cohen, James M. Hansen

Low energy theorems have been derived for the coefficients of the effective range expansion in s-wave nucleon-nucleon scattering valid to leading nontrivial order in an expansion based $Q$ counting, a scheme in which both $m_π$ and $1/a$ (where $a$ is the scattering length) are treated as small mass scales. Previous tests of these theorems based on coefficie

P. G. Blunden, M. Burkardt, G. A. Miller

A light-front treatment for spherical nuclei is developed from a relativistic effective Lagrangian and employing the mean field approximation. Minimizing the nuclear minus momentum subject to the constraint that, in the rest frame, the expectation values of the plus- and minus-momenta are the same leads to a formalism in which rotational invariance is recove

M. Germain, Ch. Hartnack, J. L. Laville, J. Aichelin

Several models have been proposed to simulate heavy ion reactions beyond the mean field level. The lack of data in phase space regions which may be sensitive to different treatments of fluctuations made it difficult to judge these approaches. The recently published high energy proton spectra, measured in the reaction 94 AMeV Ar + Ta, allow for the first time

I. A. Pshenichnov, I. N. Mishustin, J. P. Bondorf, A. S. Botvina

We study nuclear reactions induced by virtual photons associated with Lorentz-boosted Coulomb fields of ultrarelativistic heavy ions. Evaporation, fission and multifragmentation mechanisms are included in a new RELDIS code, which describes the deexcitation of residual nuclei formed after single and double photon absorption in peripheral heavy-ion collisions.

W. Florkowski, W. Broniowski

We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out the importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse co

F. Delduc, F. Gieres, S. Gourmelen, S. Theisen

The standard format of matrices belonging to Lie superalgebras consists of partitioning the matrices into even and odd blocks. In this paper, we study other possible matrix formats and in particular the so-called diagonal format which naturally occurs in various applications, e.g. in superconformal field theory, superintegrable models, for super W-algebras a

C. Quesne, N. Vansteenkiste

We study in detail the spectrum of the bosonic oscillator Hamiltonian associated with the $C_3$-extended oscillator algebra \algthree, where $C_3$ denotes a cyclic group of order three, and classify the various types of spectra in terms of the algebra parameters $α_0, α_1$. In such a classification, we identify those spectra having an infinite number of peri

A. K. Pogrebkov, M. C. Prati

Ablowitz-Ladik linear system with range of potential equal to {0,1} is considered. The extended resolvent operator of this system is constructed and the singularities of this operator are analyzed in detail.

E. Lerman, T. F. Tokieda

We generalize the Weinstein-Moser theorem on the existence of nonlinear normal modes near an equilibrium in a Hamiltonian system to a theorem on the existence of relative perodic orbits near a relative equilibrium in a Hamiltonian system with continuous symmetries. In particular we prove that under appropriate hypotheses there exist relative periodic orbits

S. Kaliszewski, John Quigg, Iain Raeburn

Given a labeling c of the edges of a directed graph E by elements of a discrete group G, one can form a skew-product graph E cross_c G. We show, using the universal properties of the various constructions involved, that there is a coaction delta of G on C*(E) such that C*(E cross_c G) is isomorphic to the crossed product C*(E) cross_delta G. This isomorphism

Jinqiao Duan, James R. Brannan, H. Gao

We investigate the nonlocal behavior of passive tracer dispersion with random stopping at various sites in fluids. This kind of dispersion processes is modeled by an integral partial differential equation, i.e., an advection-diffusion equation with a memory term. We have shown the exponential decay of the passive tracer concentration, under suitable conditio

Jinqiao Duan, James R. Brannan, Vincent J. Ervin

Stochastic dynamical systems arise as models for fluid particle motion in geophysical flows with random velocity fields. Escape probability (from a fluid domain) and mean residence time (in a fluid domain) quantify fluid transport between flow regimes of different characteristic motion. We consider a quasigeostrophic meandering jet model with random perturba

S. S. Abhyankar, A. Assi

The contact structure of two meromorphic curves gives a factorization of their jacobian.

Daniel S. Sage

Let $G$ be a semisimple, simply connected, algebraic group over an algebraically closed field $k$ with Lie algebra $\frak g$. We study the spaces of parahoric subalgebras of a given type containing a fixed nil-elliptic element of $\frak g\otimes k((π))$, i.e. fixed point varieties on affine flag manifolds. We define a natural class of $k^*$-actions on affine

Heike Mildenberger, Saharon Shelah

We show: There are pairs of universes V_1 subseteq V_2 and there is a notion of forcing P in V_1 such that the change mentioned in the title occurs when going from V_1[G] to V_2[G] for a P-generic filter G over V_2. We use forcing iterations with partial memories. Moreover, we implement highly transitive automorphism groups into the forcing orders.

Mirko Primc

In this paper we introduce a notion of vertex Lie algebra U, in a way a "half" of vertex algebra structure sufficient to construct the corresponding local Lie algebra L(U) and a vertex algebra V(U). We show that we may consider U as a subset of V(U) which generates V(U) and that the vertex Lie algebra structure on U is induced by the vertex algebra s

V. Deaconu, A. Kumjian, P. Muhly

We compute the sheaf cohomology of a groupoid built from a local homeomorphism of a locally compact space $X$. In particular, we identify the twists over this groupoid, and its Brauer group. Our calculations refine those made by Kumjian, Muhly, Renault and Williams in the case $X$ is the path space of a graph, and the local homeomorphism is the shift. We als

S. C. Power

Various partially ordered Grothendieck group invariants are introduced for general operator algebras and these are used in the classification of direct systems and direct limits of finite-dimensional complex incidence algebras with common reduced digraph H (systems of H-algebras). In particular the dimension distribution group G(A; C), defined for an operato

Richard E. Borcherds

The main result of this paper is the construction of ``good'' integral forms for the universal enveloping algebras of the fake monster Lie algebra and the Virasoro algebra. As an application we construct formal group laws over the integers for these Lie algebras. We also prove a form of the no-ghost theorem over the integers, and use this to verify a

S. A. Paston, V. A. Franke

The relationship between the perturbation theory in light-front coordinates and Lorentz-covariant perturbation theory is investigated. A method for finding the difference between separate terms of the corresponding series without their explicit evaluation is proposed. A procedure of constructing additional counter-terms to the canonical Hamiltonian that comp

P. Ouyang, V. Mohta, R. L. Jaffe

We consider the dynamics of a relativistic Dirac particle constrained to move in the interior of a twisted tube by confining boundary conditions, in the approximation that the curvature of the tube is small and slowly varying. In contrast with the nonrelativistic theory, which predicts that a particle's spin does not change as the particle propagates alo

Dongsu Bak, Koji Hashimoto, Bum-Hoon Lee, Hyunsoo Min

The numbers of bosonic and fermionic zero modes of multi-pronged strings are counted in ${\cal N}=4$ super-Yang-Mills theory and compared with those of the IIB string theory. We obtain a nice agreement for the fermionic zero modes, while our result for the bosonic zero modes differs from that obtained in the IIB string theory. The possible origin of the disc

O. J. P. Eboli, E. M. Gregores, F. Halzen

The D0 Collaboration has recently reported the measurement of J/ψproduction at low angle. We show here that the inclusion of color octet contributions in any framework is able to reproduce this data.

F. Jegerlehner

I review recent evaluations of the hadronic contributions to the muon anomalous magnetic moment (g-2)_mu and to the effective fine structure constant alpha (M_Z). A new estimate for the hadronic shift delta_alpha hadronic = 0.027782 +/- 0.000254 is presented which implies 1/alpha (M_Z) = 128.913 +/- 0.035. It is based on a recent perturbative calculation of

T. Becher, H. Leutwyler

We show that in the presence of massive particles such as nucleons, the standard low energy expansion in powers of meson momenta and light quark masses in general only converges in part of the low energy region. The expansion of the scalar form factor $σ(t)$, for instance, breaks down in the vicinity of $t=4M_π^2$. In the language of heavy baryon chiral pert

R. Botet, M. Ploszajczak

Recently equations for the generating functional in the perturbative quantum chromodynamics (QCD) have been extended by including the non-perturbative dissipation in QCD jets. The resulting equations have been solved rigorously and new family of scaling solutions, the so-called delta - scaling, generalizing the well-known Kubo-Nielsen-Olesen scaling law for

A. Bialas, K. Zalewski

It is shown that the recently established strong mass- dependence of the radii of the hadron sources, as observed in HBT analyses of the $e^+e^-$ annihilation, can be explained by assuming a generalized inside-outside cascade, i.e. that (i) the four-momenta and the space-time position four-vectors of the produced particles are approximately proportional to e

Johan Bijnens, Ulf-G. Meissner

These are the proceedings of the workshop on ``Chiral Effective Theories'' held at the Physikzentrum Bad Honnef of the Deutsche Physikalische Gesellschaft, Bad Honnef, Germany from November 30 to December 4, 1998. The workshop concentrated on Chiral Perturbation Theory in its various settings and its relations with lattice QCD and dispersion theory.

José Luis Cortés

A recently conjectured relashionship between UV and IR cutoffs in an effective field theory without quantum gravity is generalized in the presence of large extra dimensions. Estimates for the corrections to the usual calculation of observables within quantum field theory are used to put very stringent limits, in some cases, on the characteristic scale of the

W. Bentz, T. Hama, T. Matsuki, K. Yazaki

The NJL model is formulated on the light cone. Using the 1/N expansion to solve the fermionic constraint, an effective 4-fermi lagrangian is derived. Pionic properties are investigated using this lagrangian, and the formal equivalence to the equal-time formulation is demonstrated. Two regularization schemes in terms of light-cone variables are discussed: An

M. Guagnelli, K. Jansen, R. Petronzio

We present evidence for the universality of the continuum limit of the scale dependence of the renormalization constant associated with the operator corresponding to the average momentum of non-singlet parton densities. The evidence is provided by a non-perturbative computation in quenched lattice QCD using the Schrödinger Functional scheme. In particular, w

D. Muller, representing the SLD Collaboration

We review recent Z^0 physics results from SLD that use the Cherenkov Ring Imaging Detector for charged particle identification. The performance of the detector and likelihood method are described briefly. Several hadronization measurements are presented, including identified hadron production in events of different primary flavors, leading hadron production,

Li-Xin Li

In this paper time machines are constructed from anti-de Sitter space. One is constructed by identifying points related via boost transformations in the covering space of anti-de Sitter space and it is shown that this Misner-like anti-de Sitter space is just the Lorentzian section of the complex space constructed by Li, Xu, and Liu in 1993. The others are co

V. Ferrari, L. Gualtieri, A. Borrelli

We compute the energy spectra of the gravitational signals emitted when a mass m is scattered by the gravitational field of a star of mass M >> m. We show that, unlike black holes in similar processes, the quasi-normal modes of the star are excited, and that the amount of energy emitted in these modes depends on how close the exciting mass can get to the sta

U. Ruediger, J. Yu, L. Thomas, S. S. P. Parkin

Large negative magnetoresistance (MR) observed in transport measurements of hcp Co films with stripe domains were recently reported and interpreted in terms of a novel domain wall (DW) scattering mechanism. Here detailed MR measurements, magnetic force microscopy, and micromagnetic calculations are combined to elucidate the origin of MR in this material. The

R. Botet, M. Ploszajczak

Two standard models of sol-gel transition are revisited here from the point of view of their fluctutations in various moments of both the mass-distribution and the gel-mass. Bond-percolation model is an at-equilibrium system and undergoes a static second-order phase transition, while Monte-Carlo Smoluchowski model is an off-equilibrium one and shows a dynami

Yi-Cheng Zhang

Empirical evidence suggests that even the most competitive markets are not strictly efficient. Price histories can be used to predict near future returns with a probability better than random chance. Many markets can be considered as {\it favorable games}, in the sense that there is a small probabilistic edge that smart speculators can exploit. We propose to

M. Farine, P. Schuck, X. Vinas

The moment of inertia of a trapped superfluid gas of atomic Fermions (6Li) is calculated as a function of two system parameters: temperature and deformation of the trap. For moderate deformations at zero temperature the moment of inertia takes on the irrotational flow value. Only for T very close to the critical temperature rigid rotation is attained. For ve