February 1998 arXiv papers — page 7

Alexandre Telnov

The possibility of using an IBM PC-compatible computer as an NFS file server for a moderate-size workgroup has been explored. A pilot project currently under way at LBNL has proven that this platform does indeed provide a viable alternative to commercially available file servers at a fraction of the cost without significant sacrifices in performance and reli

Ina Sarcevic

We find that coherent multiple scatterings of the partonic fluctuations of the virtual photon with the nucleons inside the nucleus result in the large nuclear shadowing effect for parton distributions in nuclei. We predict the gluon shadowing effect at small $x$ and for $Q^2\geq 3 GeV^2$.

M. Baldo, G. F. Burgio, H. Q. Song, F. Weber

We study the properties of static and rotating neutron stars adopting non-relativistic equations of state (EOS) for asymmetric nuclear matter based on the Brueckner-Hartree-Fock (BHF) scheme. The BHF calculation, with the continuous choice for the single particle potential, appears to be very close to the full EOS, which includes the three-hole line contribu

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

We present here the first application of realistic shell model (SM) including coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states to the spectroscopy of 8B and to the calculation of astrophysical factors in the reaction 7Be(p,gamma)8B.

V. A. Karmanov

The general spin structure of the relativistic nucleon wave function in the $3q$-model is found. It contains 16 spin components, in contrast to 8 ones known previously, since in a many-body system the parity conservation does not reduce the number of the components. The explicitly covariant form of the wave function automatically takes into account the relat

Mikhail Grinberg

We describe the Morse groups of the nearby cycles sheaves on the nilcones in three classical symmetric spaces.

Nitin Nitsure

In characteristic zero, semistable principal bundles on a nonsingular projective curve with a semisimple structure group form a bounded family, as shown by Ramanathan in 1970's using the Narasimhan-Seshadri theorem. This was the first step in his construction of moduli for principal bundles. In this paper we prove boundedness in finite characteristics (o

Ulrike Tillmann

Motivated by ideas from string theory and quantum field theory new invariants of knots and 3-dimensional manifolds have been constructed from complex algebraic structures such as Hopf algebras (Reshetikhin and Turaev), monoidal categories with additional structure (Turaev and Yetter), and modular functors (Walker and Kontsevich). These constructions are very

Marco Manetti

It is proved that the number of deformation types of complex structures on a fixed oriented smooth four-manifold can be arbitrarily large. The considered examples are locally simple abelian covers of rational surfaces.

Jasper V. Stokman, Mathijs S. Dijkhuizen

We study irreducible *-representations of a certain quantization of the algebra of polynomial functions on a generalized flag manifold regarded as a real manifold. All irreducible *-representations are classified for a subclass of flag manifolds containing in particular the irreducible compact Hermitian symmetric spaces. For this subclass it is shown that th

Albert Jeu-Liang Sheu

We show that the C*-algebra of a quantum sphere $C(S_{q}^{2n+1})$ can be realized as a groupoid C*-algebra of a groupoid which is explicitly identified and is independent of the parameter $q$.

Albert Jeu-Liang Sheu

We show how the C*-algebras of quantum complex projective spaces (standard or nonstandard) are related to groupoids.

Albert Jeu-Liang Sheu

We show that the standard SU(n)-covariant Poisson sphere $S^{2n-1}$ is embedded in the nonstandard $SU(n+1)$-covariant Poisson complex projective spaces $CP^{n}$.

Tonnis A. ter Veldhuis

We study supersymmetric SU(5) chiral gauge theories with 2 fields in the 10 representation, $2+N_F$ fields in the $\bar{5}$ representation and $N_F$ fields in the 5 representation, for $N_F=0,1,2$. With a suitable superpotential, supersymmetry is shown to be broken dynamically for each of these values of $N_F$. We analyze the calculable limit for the model w

Theodora Ioannidou, Wojtek Zakrzewski

This paper deals with classical solutions of the modified chiral model on $R^{2+1}$. Such solutions are shown to correspond to products of various factor which we call time-dependent unitons. Then the problem of solving the system of second-order partial differential equations for the chiral field is reduced to solving a sequence of systems of first-order pa

Bernard de Wit, Jan Louis

In these lectures we review how some of the recent developments in string theory are closely related to generic properties of supersymmetry. Lectures given at the Nato Advanced Study Institute on "Strings, Branes and Dualities", Cargese, May 26 - June 14, 1997.

E143 collaboration

Measurements are reported of the proton and deuteron spin structure functions g1 at beam energies of 29.1, 16.2, and 9.7 GeV and g2 at a beam energy of 29.1 GeV. The integrals of g1 over x have been evaluated at fixed Q**2 = 3 (GeV/c)**2 using the full data set. The Q**2 dependence of the ratio g1/F1 was studied and found to be small for Q**2 > 1 (GeV/c)**2.

V. Barger

The potential of muon colliders to study a low-energy supersymmetry is addressed in the framework of the minimal supergravity model, whose predictions are first briefly surveyed. Foremost among the unique features of a muon collider is s-channel production of Higgs bosons, by which Higgs boson masses, widths, and couplings can be precisely measured to test t

D. V. Antonov, D. Ebert

A topological term related to the number of self-intersections of the string world-sheet is shown to emerge in the string representation of the Wilson loop in the dilute instanton gas. The coupling constant of this term occurs to be proportional to the topological charge of the instanton gas under consideration.

V. Berezinsky

The current status of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with emphasis given to theoretical interpretation of the observed events. The galactic and extragalactic origin, in case of astrophysical sources of UHE particles, have the problems either with acceleration to the observed energies or with the fluxes and spectra. Topological defects can

K. J. Eskola, V. J. Kolhinen, P. V. Ruuskanen

Using the NMC and E665 nuclear structure function ratios $F_2^A/F_2^D$ and $F_2^A/F_2^{C}$ from deep inelastic lepton-nucleus collisions, and the E772 Drell--Yan dilepton cross sections from proton-nucleus collisions, and incorporating baryon number and momentum sum rules, we determine nuclear parton distributions at an initial scale $Q_0^2$. With these dist

D. Delepine

Assuming a new interaction with a $θ$ term for the third generation of quarks, a value of $θ$ different from zero dynamically induces the top- bottom mass splitting and a large CP-violating phase.

Jian-Jun Yang, Bo-Qiang Ma, Guang-Lie Li

We investigate the non-perturbative effects on the ratio $R=σ_L /σ_T$ in lepton-nucleon deep inelastic scattering by taking into account the lowest dimensional condensate contributions from the QCD vacuum. By combining conventional perturbative QCD corrections and the Georgi- Politzer target-mass effects with the non-perturbative effects from the QCD vacuum,

F. Bossi, G. Colangelo, G. Isidori

The perspectives of a search for the rare decay $K_L\toπ^0ν\barν$ at a Phi-factory are discussed. After a general analysis, we focus on the realistic case of KLOE and DAFNE, showing that limits of the order of $10^{-9}$ on BR($K_L\toπ^0ν\barν$) are achievable in the next few years. We also discuss the theoretical implications of this kind of measurements.

Chung Kao

The prospects for discovering neutral Higgs bosons in the minimal supersymmetric model (MSSM) and in the minimal supergravity model at the LHC are investigated. Two special discovery channels are discussed: (i) the decay mode of the MSSM CP-odd Higgs boson into photon pairs, and (ii) the decays of neutral Higgs bosons into muon pairs in the MSSM as well as i

Satoshi Matsuda

This is a report of the concluding talk presented at the International Symposium on QCD Corrections and New Physics which was held during October 27-29, 1997 at Mielparque Hiroshima, Hiroshima, Japan. The report will be published in the Conference Proceedings.

F. E. Close

Lattice QCD predicts a rich spectroscopy of glueballs and $q\bar{q}-$glue h ybrids. I compare these with data and assess the emerging empirical situation. Questions for the lattice are proposed.

C. T. H. Davies, K. Hornbostel, G. P. Lepage, A. Lidsey

We present results for the spectrum of b-bbar bound states in the quenched approximation for three different values of the lattice spacing. Results for spin-independent splittings are shown to have good scaling behaviour; spin-dependent splittings are more sensitive to discretisation effects. We discuss what needs to be done to match the experimental spectru

CDF collaboration

We present an analysis of dilepton events originating from top-antitop production in proton-antiproton collisions at sqrt{s}=1.8 TeV at the Fermilab Tevatron Collider. The sample corresponds to an integrated luminosity of 109+-7 pb^{-1}. We observe 9 candidate events, with an estimated background of 2.4+-0.5 events. We determine the mass of the top quark to

C. Evangelista, A. Palano, D. Drijard, N. H. Hamann

A study has been performed of the reaction pbar p -> 4K using in-flight antiprotons from 1.1 to 2.0 GeV/c incident momentum interacting with a hydrogen jet target. The reaction is dominated by the production of a pair of phi mesons. The pbar p -> phi phi cross section rises sharply above threshold and then falls continuously as a function of increasing antip

Laurence Littenberg

I discuss the prospects for a fixed target physics program at the AGS in the RHIC era.

Aroonkumar Beesham

Using an energy-momentum complex we give a physical interpretation to the constants in the well-known static spherically symmetric asymptotically flat vacuum solution to the Brans-Dicke equations. The positivity of the tensor mass puts a bound on parameters in the solution.

Alberto Barchielli, Fabio Zucca

Stochastic differential equations for processes with values in Hilbert spaces are now largely used in the quantum theory of open systems. In this work we present a class of such equations and discuss their main properties; moreover, we explain how they are derived from purely quantum mechanical models, where the dynamics is represented by a unitary evolution

B. Elattari, V. Kagalovsky, H. A. Weidenmueller

We derive a non-linear supersymmetric sigma-model for the transport of light (classical waves) through a disordered medium. We compare this model with the well-established non-linear sigma-model for the transport of electrons (Schroedinger waves) and display similarities of and differences between both cases. We show that for weak disorder, both models are e

Michael Widom, Jose A. Miranda

Viscous fingering occurs in the flow of two immiscible, viscous fluids between the plates of a Hele-Shaw cell. Due to pressure gradients or gravity, the initially planar interface separating the two fluids undergoes a Saffman-Taylor instability and develops finger-like structures. When one of the fluids is a ferrofluid and a perpendicular magnetic field is a

Gregor Huber, Thomas A. Vilgis

The adsorption of a single ideal polymer chain on energetically heterogeneous and rough surfaces is investigated using a variational procedure introduced by Garel and Orland (Phys. Rev. B 55 (1997), 226). The mean polymer size is calculated perpendicular and parallel to the surface and is compared to the Gaussian conformation and to the results for polymers

U. Frisch, A. Mazzino, M. Vergassola

A Lagrangian method for the numerical simulation of the Kraichnan passive scalar model is introduced. The method is based on Monte--Carlo simulations of tracer trajectories, supplemented by a point-splitting procedure for coinciding points. Clean scaling behavior for scalar structure functions is observed. The scheme is exploited to investigate the dependenc

Milica Milovanovic, Efrat Shimshoni

We study the edge--states excitations of a droplet of quantum Hall liquid embedded in an electron (Wigner) solid. The presence of strong correlations between the liquid and solid sectors in the ground state is shown to be reflected in the density of states $D(E)$, associated with the excitations of the liquid--solid interface. We find that the prominent effe

H. Aschauer, U. Schollwoeck

We study an AFM Heisenberg S=2 quantum spin chain at T=0 with both interaction and on-site anisotropy, H = \sum_{i} {1/2}(S^{+}_{i}S^{-}_{i+1}+S^{-}_{i}S^{+}_{i+1}) +J^{z}S^{z}_{i}S^{z}_{i+1}+D(S^{z}_{i})^{2}. Contradictory scenarios exist for the S=2 anisotropic phase diagram, implying different mechanisms of the emergence of the classical limit. One main A

M. V. Budantsev, Z. D. Kvon, A. G. Pogosov, G. M. Gusev

We investigate the transport in a two-dimensional (2D) lattice of coupled Sinai billiards fabricated on the basis of a high-mobility 2D electron gas in GaAs/AlGaAs heterojunction. For the states with low reduced conductivity g<<1 an anomalously weak temperature dependence of g was found. The large negative magnetoresistance described by the Lorentz line-shap

Jun-ichiro Kishine, Kenji Yonemitsu

Effects of the electron-electron umklapp process on dimensional crossovers caused by the interchain one-particle hopping, $t_{\perp}$, in a weakly-coupled half-filled chain system have been studied, based on the perturbative renormalization-group approach. The variance of $t_\perp$ and the umklapp process under scaling is taken into account. We found that th

Jun-ichiro Kishine, Kenji Yonemitsu

Based on the perturbative renormalization group (PRG) approach, we have studied dimensional crossovers in Hubbard ladders coupled via weak interladder one-particle hopping, $t_{\perp}$. We found that the one-particle crossover is strongly suppressed through growth of the intraladder scattering processes which lead the isolated Hubbard ladder system toward th

Mark A. Fardal, Mark L. Giroux, J. Michael Shull

Absorption due to HeII Ly-alpha has been detected at low resolution in the spectra of four quasars between redshifts z = 2.74-3.29. We assess these observations, giving particular attention to the radiative transfer of the ionizing background radiation, cloud diffuse emission and ionization physics, and statistical fluctuations. We use high-resolution observ

T. Kodama, N. Arimoto, A. J. Barger, A. Aragon-Salamanca

We present a thorough quantitative analysis of the evolution of the colour-magnitude relation for early-type galaxies in 17 distant clusters with redshifts 0.31 < z < 1.27 using the Kodama & Arimoto (1997) evolutionary model for elliptical galaxies. The model is calibrated to reproduce the colour- magnitude relation for Coma ellipticals at z ~ 0 and gives th

L. Binette

The line ratios from coronal gas in Seyferts can be successfully fitted with photoionized clouds of high densities and low volume filling factor. The ionization parameter implied is sufficiently high that models must consider the effect of radiation pressure from the active nucleus. In spite of the nucleus gravitational force, radiation pressure is sufficien

F. Bernardeau

Weak lensing effects are known to introduce non-linear couplings in CMB temperature maps. In inflationary scenario, the primary CMB anisotropies are expected to form a 2D Gaussian map, for which, the probability distribution function of the ellipticity defined from the local temperature curvature matrix has a very specific shape. I show that lenses alter sig

J. E. Grove, W. N. Johnson, R. A. Kroeger, K. McNaron-Brown

OSSE has observed seven transient black hole candidates: GRO J0422+32, GX339-4, GRS 1716-249, GRS 1009-45, 4U 1543-47, GRO J1655-40, and GRS 1915+105. Two gamma-ray spectral states are evident and, based on a limited number of contemporaneous X-ray and gamma-ray observations, these states appear to be correlated with X-ray states. The former three objects sh

B. T. Draine, A. Lazarian

We discuss the rotational excitation of small interstellar grains and the resulting electric dipole radiation from spinning dust. Attention is given to excitation and damping of rotation by: collisions with neutrals; collisions with ions; plasma drag; emission of infrared radiation; emission of microwave radiation; photoelectric emission; and formation of H_

Heino Falcke

This paper summarizes some of our recent projects which try to illuminate the nature and importance of jets associated with active nuclei and compact objects. After a short introduction on jets in radio galaxies and radio loud quasars the paper focuses on jets in other source types, such as radio-quiet quasars, Seyfert and LINER galaxies, and stellar mass bl

Javier Gorosabel, Alberto J. Castro-Tirado

We have examined 8004 plates at the Harvard College Observatory Plate Collection searching for optical transient emission from the gamma-ray burst GRB 970228. This is the first archival search carried out so far for a gamma-ray burst with known transient optical emission. The total exposure time amounts to ~1.1 yr. No convincing optical activity was found ab

D. Enstrom, S. Fredriksson, J. Hansson, A. Nicolaidis

We present a new scenario for the development of the Universe after the Big Bang, built on the conjecture that a vast majority of the primordial quark matter did not undergo a phase transition to normal nuclear matter, but rather split up into massive quark objects that remained stable. Hence, such primordial quark matter would make up the so-called dark mat

Ruth Gruenwald, Sueli M. Viegas

Type I planetary nebulae (PNe) are defined as those with high He and N abundances (Peimbert & Torres-Peimbert 1983). These objects present in general bipolar geometries and have high stellar temperatures (Corradi & Schwarz 1995, Torres-Peimbert & Peimbert 1997). In this paper we analyse the empirical methods for abundance determination in order to check if t

S. D. Biller, J. Buckley, A. Burdett, J. Bussons Gordo

From considering the effect of gamma-gamma interactions on recently observed TeV gamma-ray spectra, improved limits are set to the density of extragalactic infrared (IR) photons which are robust and essentially model-independent. The resulting limits are up to two orders of magnitude more restrictive than direct observations in the 0.025-0.3eV regime. These

Guinevere Kauffmann, Stephane Charlot

There are two major approaches to modelling galaxy evolution. The traditional view is that the most massive galaxies were assembled early and have evolved with steeply declining star formation rates since a redshift of 2 or higher. According to hierarchical theories, massive galaxies were assembled much more recently from mergers of smaller subunits. Here we

Ethan T. Vishniac

Accretion disk outbursts, and their subsequent decline, offer a unique opportunity to constrain the physics of angular momentum transport in hot accretion disks. Recent work has centered on the claim by Cannizzo et al. that the exponential decay of luminosity following an outburst in black hole accretion disk systems is only consistent with a particular form

C. L. Carilli, H. J. A. Rottgering, G. K. Miley L. Pentericci, D. E. Harris

We review some aspects of radio continuum polarimetric imaging of high redshift radio galaxies. The correlation between extreme values of Faraday rotation observed toward radio emitting structures in nearby radio galaxies, and X-ray emitting cluster atmospheres, is presented as a method for targeting objects at high redshift for deep X-ray searches. We prese

Andrew D. Jacobs, J. F. Cornwell

We classify all 4-dimensional first order bicovariant calculi on the Jordanian quantum group GL_{h,g}(2) and all 3-dimensional first order bicovariant calculi on the Jordanian quantum group SL_{h}(2). In both cases we assume that the bicovariant bimodules are generated as left modules by the differentials of the quantum group generators. It is found that the

Timo van Ritbergen, Robin G. Stuart

Hadronic corrections to the muon lifetime are calculated in the Fermi theory in the presence of QED using dispersion relations. The result, after convolution of hadron data with the calculated perturbative kernel is Delta Gamma_had = -Gamma_0(alpha/pi)^2(0.042) where Gamma_0 is the tree-level width. The results are also used to obtain the corrections to the

Yun Wang, David N. Spergel, Michael A. Strauss

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both $A_S^2(k)$ and the cosmological parameters by combining the data from the Microwave Anisotropy Probe (MAP) and the galax

Hooman Davoudiasl, Eric Westphal

To estimate the diffusion constant $D$ of particles in a plasma, we develop a method that is based on the mean free path $λ$ for scatterings with momentum transfer $q >~ T$. Using this method, we estimate $λ$ and $D$ for squarks and quarks during the electroweak phase transition. Assuming that Debye and magnetic screening lengths provide suitable infrared cu

K. H. Ahn, A. J. Millis

A model of localized classical electrons coupled to lattice degrees of freedom and, via the Coulomb interaction, to each other, has been studied to gain insight into the charge and orbital ordering observed in lightly doped manganese perovskites. Expressions are obtained for the minimum energy and ionic displacements caused by given hole and electron orbital

N. E. Mavromatos, A. Momen

We study the appearance of induced parity-violating magnetic moment, in the presence of external magnetic fields, for even-number of fermion species coupled to dynamical fields in three dimensions. Specifically, we use a SU(2)xU(1) gauge model for dynamical gauge symmetry breaking, which is also proposed recently as a field theoretical model for high-tempera

David Hochberg, Matt Visser

Adapting and extending a suggestion due to Page, we define a wormhole throat to be a marginally anti-trapped surface, that is, a closed two-dimensional spatial hypersurface such that one of the two future-directed null geodesic congruences orthogonal to it is just beginning to diverge. Typically a dynamic wormhole will possess two such throats, corresponding

B. Bäuml, G. Wellein, H. Fehske

To discuss the interplay of electronic and lattice degrees of freedom in systems with strong Coulomb correlations we have performed an extensive numerical study of the two-dimensional Holstein t-J model. The model describes the interaction of holes, doped in a quantum antiferromagnet, with a dispersionsless optical phonon mode. We apply finite-lattice Lanczo

Marc Henneaux, Andre&#39; Wilch

The local BRST cohomology of the gauged non-linear sigma model on a group manifold is worked out for any Lie group G. We consider both, the case where the gauge field is dynamical and the case where it has no kinetic term (G/G topological theory). Our results shed a novel light on the problem of gauging the WZW term as well as on the nature of the topologica

S. W. Allen, A. C. Fabian

We examine the effects of cooling flows on the T_X-L_Bol relation for a sample of the most X-ray luminous (L_Bol > 10^45 erg/s) clusters of galaxies known. Using high-quality ASCA X-ray spectra and ROSAT images we explicitly account for the effects of cooling flows on the X-ray properties of the clusters and show that this reduces the previously-noted disper

M. Kaulke, I. Peschel

The spin one-half Heisenberg chain with $U_q[SU(2)]$ symmetry is studied via density-matrix renormalization. Ground-state energy and $q$-symmetric correlation functions are calculated for the non-hermitian case $q=\exp(iπ/(r+1))$ with integer $r$. This gives bulk and surface exponents for (para)fermionic correlations in the related Ising and Potts models. Th

Konstantin G. Zloshchastiev

The spherically symmetric singular perfect fluid shells are considered for the case of their radii being equal to the event horizon (the black shells). We study their observable masses, depending at least on the three parameters, viz., the square speed of sound in the shell, instantaneous radial velocity of the shell at a moment when it reaches the horizon,

Konstantin G. Zloshchastiev

The spherically symmetric thin shells of the barotropic fluids with the linear equation of state are considered within the frameworks of general relativity. We study several aspects of the shells as completely relativistic models of stars, first of all the neutron stars and white dwarfs, and circumstellar shells. The exact equations of motion of the shells a

O. B. Zaslavskii

It is argued that the existence of constant dilaton field solutions is a generic feature of string-inspired dilaton gravity. Such solutins arise in the extreme limit of black hole metrics. It is shown that in a strong coupling region quantum effects give rise to two horizons in thermal equilibrium that has no classical counterpart.

Jintai Ding, Boris Feigin

In this paper, we establish the connection between the quantized W-algebra of ${\frak sl}(2,1)$ and quantum parafermions of $U_q(\hat {\frak sl}(2))$ that a shifted product of the two quantum parafermions of $U_q(\hat {\frak sl}(2))$ generates the quantized W-algebra of ${\frak sl}(2,1)$.

Andrei Linde

We discuss a dramatic difference between the description of the quantum creation of an open universe using the Hartle-Hawking wave function and the tunneling wave function. Recently Hawking and Turok have found that the Hartle-Hawking wave function leads to a universe with Omega = 0.01, which is much smaller that the observed value of Omega > 0.3. Galaxies i

Sang-Yoon Kim, Bambi Hu

We consider a parametrically forced pendulum with a vertically oscillating suspension point. It is well known that, as the amplitude of the vertical oscillation is increased, its inverted state (corresponding to the vertically-up configuration) undergoes a cascade of ``resurrections,&#39;&#39; i.e., it becomes stabilized after its instability, destabilize ag

J. Bland-Hawthorn, S. Veilleux, G. Cecil, M. Putman

The Smith high velocity cloud (V(LSR) = 98 kms) has been observed at two locations in the emission lines [OIII]5007, [NII]6548 and H-alpha. Both the [NII] and H-alpha profiles show bright cores due to the Reynolds layer, and red wings with emission extending to V(LSR) = 130 kms. This is the first simultaneous detection of two emission lines towards a high ve

S. W. Allen, A. C. Fabian

We explore the relationship between the metallicity of the intracluster gas in clusters of galaxies, determined by X-ray spectroscopy, and the presence of cooling flows. Using ASCA spectra and ROSAT images, we demonstrate a clear segregation between the metallicities of clusters with and without cooling flows. On average, cooling-flow clusters have an emissi

Gary T. Horowitz, Hirosi Ooguri

Recently, Maldacena proposed that the large N limit of the N=4 supersymmetric gauge theory in four dimensions with U(N) gauge group is dual to the type IIB superstring theory on AdS_5 x S^5. We use this proposal to study the spectrum of the large N gauge theory on R x S^3 in a low energy regime. We find that the spectrum is discrete and evenly spaced, and th

Gonzalo Garcia de Polavieja

The different time-dependent distances of two arbitrarily close quantum or classical-statistical states to a third fixed state are shown to imply an experimentally relevant notion of state sensitivity to initial conditions. A quantitative classification scheme of quantum states by their sensitivity and instability in state space is given that reduces to the

R. M. Kiehn

Exact radiative wave solutions to the classical homogeneous Maxwell equations in the vacuum have been found that are not transverse, exhibit both torsion and spin, and for which the second Poincare invariant, E.B, is not zero. Two four component rank 3 tensors of spin current and torsion are constructed on topological grounds. The divergence of each pseudo v

Alfonso Rueda, Bernhard Haisch

We present an approach to the origin of inertia involving the electromagnetic component of the quantum vacuum and propose this as an alternative to Mach&#39;s principle. Preliminary analysis of the momentum flux of the classical zero-point radiation impinging on accelerated objects as viewed by an inertial observer suggests that the resistance to acceleratio

Andrew E. Chubykalo, Valeri V. Dvoeglazov

We comment on the paper by M. W. Mitchell and R. Y. Chiao, ``Causality and negative group delay in a simple bandpass amplifier&#34;, Am. J. Phys. 66 (1), 14-19 (1998).

T. Kikuchi, Y. Nagai, T. S. Suzuki, T. Shima

Discrete gamma-rays from the neutron capture state of 13C to its low-lying bound states have been measured using pulsed neutrons at En = 550 keV. The partial capture cross sections have been determined to be 1.7+/-0.5, 24.2+/-1.0, 2.0+/-0.4 and 1.0+/-0.4 microb for the ground (1/2-), first (1/2+), second (3/2-) and third (5/2+) excited states, respectively.

John N. Bahcall

This talk compares standard model predictions with the results of solar neutrino experiments. Here `standard model' means the combined standard model of minimal electroweak theory plus a standard solar model. I emphasize the importance of recent analyses in which the neutrino fluxes are treated as free parameters, independent of any constraints from solar mo

James J. Griffin

A scorecard summary of the various data of the ``Sharp Lepton Problem&#39;&#39; is presented. The present situation, in which APEX reports ``...no evidence for sharp pairs...&#39;&#39; even as their data exhibits a sharp pair excess near 800 keV, is discussed. Two kinds of low energy experiments utilizing non-heavy ion processes are suggested as means to bre

M. Reiris, P. Spallanzani

Recently, a set of tools has been developed with the purpose of the study of Quantum Gravity. Until now, there have been very few attempts to put these tools into a rigorous mathematical framework. This is the case, for example, of the so called path bundle of a manifold. It is well known that this topological principal bundle plays the role of a universal b

Margaret Symington

We prove that the rational blowdown, a surgery on smooth 4-manifolds introduced by Fintushel and Stern, can be performed in the symplectic category. As a consequence, interesting families of smooth 4-manifolds, including the exotic $K3$ surfaces of Gompf and Mrowka, admit symplectic structures.

Stefan Waldmann

In this paper we construct non-equivalent star products on CP^n by phase space reduction. It turns out that the non-equivalent star products occur very natural in the context of phase space reduction by deforming the momentum map of the U(1)-action on C^{n+1} {0} into a quantum momentum map and the corresponding momentum value into a quantum momentum value s

Jonathan Fine

This paper shows how Hodge&#39;s theory of harmonic $p$-sets (a discrete version of his theory of harmonic forms) allows a new approach to be taken to the problem of providing a combinatorial definition of the Pontrjagin classes of a compact manifold. This approach is then related to the author&#39;s definition of flag vectors for hypergraphs, and other obje

S. J. Brodsky, J. R. Hiller, G. McCartor

We propose a solution to the problem of renormalizing light-cone Hamiltonian theories while maintaining Lorentz invariance and other symmetries. The method uses generalized Pauli--Villars regulators to render the theory finite. We discuss the method in the context of Yukawa theory at one loop and for a soluble model in 3+1 dimensions. The model is studied no

G. C. Branco, M. N. Rebelo, J. I. Silva-Marcos

A simple ansatz is proposed for neutrino and charged lepton mass matrices, within the framework of universal strength for Yukawa couplings. In this framework all Yukawa couplings have equal moduli and the flavour dependence is only in their phases. We take into account the solar neutrino deficit and the atmospheric neutrino anomaly, assuming three neutrino f

J. -J. Dugne, S. Fredriksson, J. Hansson, E. Predazzi

We present a new minimal model for the substructure of all known quarks, leptons and weak gauge bosons, based on only three fundamental and stable spin-1/2 preons. As a consequence, we predict three new quarks, three new leptons, and six new vector bosons. One of the new quarks has charge $-4e/3$. The model explains the apparent conservation of three lepton

B. Ananthanarayan

We show that a suitable setting for comparison of the low-energy representation for pion-pion scattering amplitudes, with dispersive representation for these amplitudes, is provided by certain manifestly crossing symmetric dispersion relations. We begin with a discussion of fixed-t dispersion relations and discuss the origin of crossing constraints that aris

S. Esposito

We analyze both chirality-changing and chirality-preserving transitions of Dirac-Majorana neutrinos. In vacuum, the first ones are suppressed with respect to the others due to helicity conservation and the interactions with a (``normal&#39;&#39;) medium practically does not affect the expressions of the probabilities for these transitions, even if the amplit

O. E. Evnin

Inner and empirically consistent model of elementary particles, including two matter structural levels beyond the quark one is built. Excitations spectra, masses and interactions are analysed using the phenomenological notion of non-pertubative vacuum condensate. Essential low-energy predictions of developed concepts are classified. Effective gauge U(1)xU(1)

T. Reisz

Hopping parameter expansions are convergent power series. Under general conditions they allow for the quantitative investigation of phase transition and critical behaviour. The critical information is encoded in the high order coefficients. Recently, 20th order computations have become feasible and used for a large class of lattice field models both in finit

G. Bimonte, D. Iñiguez, A. Tarancón, C. L. Ullod

We make a Monte Carlo study of the coupled two-scalar $λϕ^2_1ϕ^2_2$ model in four dimensions at finite temperature. We find no trace of Inverse Symmetry Breaking for values of the renormalized parameters for which perturbation theory predicts this phenomenon.

Tomohiro Hotta, Taku Izubuchi, Jun Nishimura

We apply the multicanonical technique to the three dimensional dynamical triangulation model, which is known to exhibit a first order phase transition with the Einstein-Hilbert action. We first clarify the first order nature of the phase transition with the Einstein-Hilbert action in several ways including a high precision finite size scaling analysis. We th

The OPAL Collaboration, K. Ackerstaff et al

Events with four distinct jets from e^+e^- collisions, collected by the OPAL detector at centre-of-mass energies between 130 and 184 GeV, are analysed for a peak in the sum of dijet masses. This search is motivated by the ALEPH Collaboration&#39;s observation of a clear excess of events with dijet mass sums close to 105 GeV in data taken at centre-of-mass en

Vincent Brindejonc

In this paper, a procedure which gives euclidean solutions of 3-dimensional Einstein-Yang-Mills equations when one has solutions of the Einstein equations is proposed. The method is based on reformulating Yang-Mills theory in such a way that it becomes a gravity. It is applied to find black hole solutions of the coupled Einstein-Yang-Mills equations.

W. Drechsler, H. Tann

A massless Weyl-invariant dynamics of a scalar, a Dirac spinor, and electromagnetic fields is formulated in a Weyl space, $W_4$, allowing for conformal rescalings of the metric and of all fields with nontrivial Weyl weight together with the associated transformations of the Weyl vector fields $\ka_μ$ representing the D(1) gauge fields with D(1) denoting the

Samuel Byland, David Scialom

We study the Einstein-Klein-Gordon equations for a convex positive potential in a Bianchi I, a Bianchi III and a Kantowski-Sachs universe. After analysing the inherent properties of the system of differential equations, the study of the asymptotic behaviors of the solutions and their stability is done for an exponential potential. The results are compared wi