November 1994 arXiv papers — page 4

M. Kraemer, J. Zunft, J. Steegborn, P. M. Zerwas

Inelastic photoproduction of $J/ψ$ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. We have calculated the QCD radiative corrections to the color-singlet model of this reaction. They are large at moderate photon energies, but decrease with increasing energies. The cross section and the $J/ψ$ energy spectr

R. Harlander, M. Jeżabek, J. H. Kühn, T. Teubner

Theoretical results are presented for top quarks produced in annihilation of polarized electrons on positrons. Polarization studies for $t\bar t$ pairs near threshold are free from hadronization ambiguities. This is due to the short lifetime of the top quark. Semileptonic decays are discussed as well as their applications in studying polarization dependent p

Jan Kalinowski

The prospects for discovering Higgs particles and studying their fundamental properties at future high--energy electron--positron and photon-photon colliders are reviewed. Both the Standard Model Higgs boson and the Higgs particles of its minimal supersymmetric extension are discussed. We also comment on a two Higgs doublet model searches at LEP 1. We update

A Donnachie, P V Landshoff

Exclusive vector meson production from real and virtual photons is, for the most part, described well by soft pomeron exchange. However, there are some unsolved normalisation problems, and just a hint that an additional contribution from hard pomeron exchange may be needed.

D. Atwood, G. Eilam, A. Soni

Pure leptonic radiative decays of heavy-light mesons are calculated using a very simple non-relativistic model. Dominant contribution originates from photon emission from light initial quark. We find $BR(B^\pm\to\ellνγ)\sim3.5\times10^{-6}$ and $BR(D_s\to \ellνγ)\sim1.7 \times10^{-4}$. The importance of these reactions to clarify the dynamics of the annihila

Marion Flanz, Emmanuel A. Paschos, Utpal Sarkar

We demonstrate that $CP-$violation in the Majorana mass matrices of the heavy neutrinos can generate a $CP-$asymmetric universe. The subsequent decay of the Majorana particles generates a lepton number asymmetry. During the electroweak phase transition the lepton asymmetry is converted into a baryon asymmetry, which survives down to this time.

Eric Braaten, Sean Fleming

The production rate of prompt $ψ'$'s at large transverse momentum at the Tevatron is larger than theoretical expectations by about a factor of 30. As a solution to this puzzle, we suggest that the dominant $ψ'$ production mechanism is the fragmentation of a gluon into a $c \bar c$ pair in a pointlike color-octet S-wave state, which subsequently e

Chang-Hwan Lee, Mannque Rho

This talk is based on work done in collaboration with G.E. Brown and D.-P. Min on kaon condensation in dense baryonic medium treated in chiral perturbation theory using heavy-baryon formalism. It contains, in addition to what was recently published, some new results based on the analysis on kaonic atoms by Friedman, Gal and Batty and a discussion on a renorm

L. Del Debbio, A. Di Giacomo, G. Paffuti, P. Pieri

We study the behaviour of a suitably defined disorder parameter, showing for the first time monopole condenssation in the ground state of QCD.

L. Del Debbio, A. Di Giacomo, G. Paffuti

We construct a disorder parameter for dual superconductivity of the ground state of $U(1)$ gauge theory.

M. Hasenbusch, K. Pinn, C. Wieczerkowski

We describe a method to compute renormalized coupling constants in a Monte Carlo renormalization group calculation. It can be used, e.g., for lattice spin or gauge models. The basic idea is to simulate a joint system of block spins and canonical demons. Unlike the Microcanonical Renormalization Group of Creutz et al. it avoids systematical errors in small vo

M. Caselle, F. Gliozzi, R. Fiore, M. Hasenbusch

We compare predictions of the Capillary Wave Model with Monte Carlo results for the energy gap and the interface energy of the 3D Ising model in the scaling region. Our study reveals that the finite size effects of these quantities are well described by the Capillary Wave Model, expanded to two-loop order (one order beyond the Gaussian approximation).

J Muñoz Masqué, Antonio Valdés

The number of functionally independent scalar invariants of arbitrary order of a generic pseudo--Riemannian metric on an $n$--dimensional manifold is determined.

F. Burstall, U. Hertrich-Jeromin, F. Pedit, U. Pinkall

We show how pairs of isothermic surfaces are given by curved flats in a pseudo Riemannian symmetric space and vice versa. Calapso's fourth order partial differential equation is derived and, using a solution of this equation, a Möbius invariant frame for an isothermic surface is built.

Johannes Huebschmann

Let $Σ$ be a closed surface, $G$ a compact Lie group, with Lie algebra $g$, and $ξ\colon P \to Σ$ a principal $G$-bundle. In earlier work we have shown that the moduli space $N(ξ)$ of central Yang- Mills connections, for appropriate additional data, is stratified by smooth symplectic manifolds and that the holonomy yields a diffeomorphism from $N(ξ)$ onto a

Johannes Huebschmann

Let $Σ$ be a closed surface, $G$ a compact Lie group, with Lie algebra $g$, $ξ\colon P \to Σ$ a principal $G$-bundle, let $N(ξ)$ denote the moduli space of central Yang-Mills connections on $ξ$, for suitably chosen additional data, and let $\roman{Rep}_ξ(Γ,G)$ be the space of representations of the universal central extension $Γ$ of the fundamental group of

Xuejun Zhu, P. B. Littlewood, A. J. Millis

We study the sliding state of a two-dimensional Wigner crystal in a strong magnetic field and a random impurity potential. Using a high-velocity perturbation theory, we compute the nonlinear conductivity, various correlation functions, and the interference effects arising in combined AC + DC electric effects, including the Shapiro anomaly and the linear resp

Robert J. Troy, Alan T. Dorsey

The electronic structure of the superconducting surface sheath in a type-II superconductor in magnetic fields $H_{c2}<H<H_{c3}$ is calculated self-consistently using the Bogoliubov-de Gennes equations. We find that the pair potential $Δ(x)$ exhibits pronounced Friedel oscillations near the surface, in marked contrast with the results of Ginzburg-Landau theor

Dimitri Petritis

After a rapid introduction to the physical motivations and a succinct presentation of heuristic results, this survey summarises the main mathematical results known on the Edwards-Anderson and the Sherrington-Kirkpatrick models of spin glasses. Although not complete proofs but rather sketches of the relevant steps and important ideas are given, only results f

David Carter, Manny Rayner

The Spoken Language Translator is a prototype for practically useful systems capable of translating continuous spoken language within restricted domains. The prototype system translates air travel (ATIS) queries from spoken English to spoken Swedish and to French. It is constructed, with as few modifications as possible, from existing pieces of speech and la

M. White, G. Gelmini, J. Silk

We consider the effects of a massive, unstable neutrino on the evolution of large--scale structure and anisotropies in the cosmic microwave background. Comparison with large--scale structure data allows us to rule out a wide range of masses and lifetimes for such neutrinos. We also define a range of masses and lifetimes which delay matter--radiation equality

C. H. Lineweaver, S. Hancock, G. F. Smoot, A. N. Lasenby

We have compared the Tenerife data with the {\it COBE} DMR two-year data in the declination +40°region of the sky observed by the Tenerife experiment. Using the Galactic plane signal at $\sim 30$ GHz, we show that the two data sets are cross-calibrated to within 5%. The high Galactic latitude data were investigated for the presence of common structures with

Heino Falcke, Peter L. Biermann

Starting from the assumption that radio jets and accretion disks are symbiotic features present in radio loud and radio quiet quasars we scale the bulk power of radio jets with the accretion power by adding mass- and energy conservation of the whole jet-disk system to the standard Blandford \& Königl theory for compact radio cores. The model depends on only

C. Travier

Most present and future electron accelerators require bright sources. Invented less than ten years ago, the photo-injector the principle of which is briefly recalled, has already demonstrated that it can provide very bright beams. In this paper, the most advanced photo-injector projects are reviewed, their specific features are outlined, and their major issu

A. P. Balachandran, L. Chandar, E. Ercolessi

Gauge theories on manifolds with spatial boundaries are studied. It is shown that observables localized at the boundaries (edge observables) can occur in such models irrespective of the dimensionality of spacetime. The intimate connection of these observables to charge fractionation, vertex operators and topological field theories is described. The edge obse

James D. E. Grant

We give a formulation of the vacuum Einstein equations in terms of a set of volume-preserving vector fields on a four-manifold ${\cal M}$. These vectors satisfy a set of equations which are a generalisation of the Yang-Mills equations for a constant connection on flat spacetime.

M. Wingate, T. DeGrand, S. Collins, U. Heller

We describe two calculations involving P-wave mesons made of Wilson quarks: the strong coupling constant $\alpha_s$ in the presence of two flavors of light dynamical fermions and the mass and decay constant of the $a_1$ meson.

Biswajoy Brahmachari

The one-loop evolution of Yukawa couplings in the minimal supersymmetric left-right model (MSUSYLR) model with a wide variation of the right handed breaking scale $M_R$ from 1 TeV to $10^{18}$ GeV is studied assuming that all third generation Yukawa couplings are equal and in the fixed point domain of the top quark Yuakwa coupling ($h_t$) at the Plank scale.

Jan Ambjorn

Contents: 1. Introduction 2. Bosonic propagators and random paths 3. Random surfaces and strings 4. Matrix models and two-dimensional quantum gravity 5. The mystery of $c > 1$ 6. Euclidean quantum gravity in $d > 2$ 7. Discussion

Shun-ichi Kitahara, Yoshimi Matsubara, Tsuneo Suzuki

The role of monopoles in the deconfinement transition is discussed in the framework of abelian projection in the maximally abelian gauge in $T\neq0$ $SU(2)$ QCD. Only one (or a few near $β_c$) long connected monopole loop exists uniformly through the whole lattice in each vacuum configuration in addition to some very short loops in the confinement phase and

G. Q. Li, C. M. Ko

We reexamine in the relativistic transport model the dependence of kaon yield on the nuclear equation of state in heavy ion collisions at energies that are below the threshold for kaon production from the nucleon-nucleon interaction in free space. For Au+Au collisions at 1 GeV/nucleon, we find that the kaon yield measured by the Kaos collaboration at GSI can

Sarira Sahu

The momentum projected SU(3) Chiral Color Dielectric Model (CCDM) is employed to calculate the charge root mean square radii and charge distributions of hyperons. We compare our result with Skyrme, MIT bag and Cloudy Bag model results. The charge distribution of $Λ$ in CCDM is similar to that of Skyrme Model prediction.

C. Schütz, J. W. Durso, K. Holinde, B. C. Pearce

A microscopic model for the $N\bar N\toππ$ process is presented in the meson exchange framework, which in the pseudophysical region agrees with available quasiempirical information. The scalar ($σ$) and vector ($ρ$) piece of correlated two--pion exchange in the pion--nucleon interaction is then derived via dispersion integrals over the unitarity cut. Inheren

G. Janssen, B. C. Pearce, K. Holinde, J. Speth

We investigate the structure of the scalar mesons $f_0(975)$ and $a_0(980)$ within realistic meson-exchange models of the $ππ$ and $πη$ interactions. Starting from a modified version of the Jülich model for $ππ$ scattering we perform an analysis of the pole structure of the resulting scattering amplitude and find, in contrast to existing models, a somewhat l

A. Gross, B. Hammer, M. Scheffler, W. Brenig

We performed high-dimensional quantum dynamical calculations of the dissociative adsorption and associative desorption of hydrogen on Cu(111). The potential energy surface (PES) is obtained from density functional theory calculations. Two regimes of dynamics are found, at low energies sticking is determined by the minimum energy barrier, at high energies by

Lane H. Clark, Patricia A. Evans, Michael R. Fellows, Walter D. Wallis

The learning complexity of special sets of vertices in graphs is studied in the model(s) of exact learning by (extended) equivalence and membership queries. Polynomial-time learning algorithms are described for vertex covers, independent sets, and dominating sets. The complexity of learning vertex sets of fixed size is also investigated, and it is shown that

Jindřich Zapletal

We show that there are semi-Cohen Boolean algebras which cannot be completely embedded into Cohen Boolean algebras. Using the ideas from this proof, we give a simpler argument for a theorem of S. Koppelberg and S. Shelah, stating that there are complete subalgebras of Cohen algebras which are not Cohen themselves.

P. Schaller, T. Strobl

A new class of two dimensional integrable field theories, based on the mathematical notion of Poisson manifolds, and containing gravity-Yang-Mills systems as well as the G/G gauged Wess-Zumino Witten-model, are presented. The local solutions of the classical equations of motions as well as a scheme for the quantization in a Hamiltonian formulation is present

S. M. Kuzenko, S. L. Lyakhovich, A. Yu. Segal, A. A. Sharapov

We propose the action of d=4 Anti-de Sitter (AdS) spinning particle with arbitrary fixed quantum numbers. Regardless of the spin value, the configuration space of the model is a direct product of d=4 AdS space and two-dimensional sphere corresponds to spinning degrees of freedom. The model is an AdS counterpart of the massive spinning particle in the Minkows

Parthasarathi Majumdar

Beginning with a review of the arguments leading to the so-called c=1 barrier in the continuum formulation of noncritical string theory, the pathology is then exhibited in a discretized version of the theory, formulated through dynamical triangulation of two dimensional random surfaces. The effect of embedding the string in a superspace with fermionic coordi

I. Krichever, O. Babelon, E. Billey, M. Talon

The complete solutions of the spin generalization of the elliptic Calogero Moser systems are constructed. They are expressed in terms of Riemann theta-functions. The analoguous constructions for the trigonometric and rational cases are also presented.

Johan van de Leur

We study the BKP hierarchy and prove the existence of an Adler--Shiota--van Moerbeke formula. This formula relates the action of the $BW_{1+\infty}$--algebra on tau--functions to the action of the ``additional symmetries&#39;&#39; on wave functions.

Bin Chen, Hong-Bo Teng, Ke Wu

We show that the $N=2$ and $N=4$ SUSY Yang-Mills action can be reformulated in the sense of non-commutative geometry on $M^4\times (Z_2\oplus Z_2)$ in a rather simple way. In this way the scalars or pseudoscalars are viewed as gauge fields along two directions in the space of one-forms on $Z_2\oplus Z_2$.

L. A. Dickey

This is an additional remark to the paper (hep-th 9411005) concerning a Hamiltonian structure of suggested there system of equations. The remark is inspired by a letter from L. Feher and I. Marshall.

Fiorenzo Bastianelli, Nobuyoshi Ohta

In order to investigate to what extent string theories are different vacua of a general string theory (the ``universal string&#34;), we discuss realizations of the bosonic string as particular background of certain types of $W$-strings. Our discussions include linearized $W_3^{lin}$, non-critical $W_3$, linearized $W_3^{(2)lin}$ and critical $W_3^{(2)}$ real

Alberto Sirlin

We discuss some recent developments in the evaluation of the QCD corrections to $Δρ$, their interpretation, an estimate of the theoretical error, and its effect on electroweak physics.

Stefano Catani

Experimental results on jet physics at LEP and SLC are reviewed and compared with perturbative QCD predictions. The discussion includes determinations of the strong coupling $\as$, measurements of event shape distributions and jet cross sections, studies of subjet multiplicities and tests of QCD coherence.

S. S. Khalil

In supersymmetry the anomalous magnetic moment of particles belonging to the same supermultiplet is related by simple sum rules. We study the modification of these sum rules in the case of spontaneously broken N=1 global supersymmetry.

S. P. Fraser, S. T. Fraser, R. W. Robinett

We examine the intrinsic spin-dependence of the dominant $gg \rightarrow gggg$ subprocess contribution to four-jet production in polarized proton-proton collisions using helicity amplitude techniques. We find that the partonic level, longitudinal spin-spin asymmetry, $\hat{a}_{LL}$, is intrinsically large in the kinematic regions probed in experiments detect

A. Dumitru, U. Katscher, J. A. Maruhn, H. Stöcker

We calculate thermal photon and neutral pion spectra in ultrarelativistic heavy-ion collisions in the framework of three-fluid hydrodynamics. Both spectra are quite sensitive to the equation of state used. In particular, within our model, recent data for $S+Au$ at $200$ AGeV can only be understood if a scenario with a phase transition (possibly to a quark-gl

Savely G. Karshenboim, D. I. Mendeleev

Leading logarithmic corrections to the difference of Lamb shifts of s-states $E_L(1s)-8E_L(2s)$ and to the life time of $2p_{1/2}$ state are considered. The result of Sokolov and Yakovlev for the Lamb splitting of $2s_{1/2}$ and $2p_{1/2}$ is re-evaluated and our new value is 1057.8576(21) MHz. Using value of $E_L(1s)-8E_L(2s)=$ -187.237(8) MHz, obtained her

David Bailey, Sacha Davidson

Discrepancies in measurements of the QCD running coupling constant are consistent with a new vector gauge boson coupling to baryon number with strength aB~0.1. Upsilon decays constrain such a boson to have a mass greater than about 35 GeV. It is difficult to observe such a boson in Z decays, e+e- annihilation, or hadronic interactions.

W. Bietenholz, E. Focht, U. -J. Wiese

We apply the method of Hasenfratz and Niedermayer to analytically construct perfect lattice actions for the Gross--Neveu model. In the large $N$ limit these actions display an exactly perfect scaling, i.e. cut-off artifacts are completely eliminated even at arbitrarily short correlation length. Also the energy spectrum coincides with the spectrum in the cont

K. M. Bitar, P. M. Vranas

The Nambu--Jona-Lasinio model is chirally symmetric. Addition of a Wilson term explicitly breaks this symmetry and leaves the model with a remaining parity-flavor symmetry. In the approximation of a large number of colors it has been shown that there is a phase where the remaining parity-flavor symmetry is spontaneously broken and that on the phase boundary

A. Pordt

Hierarchical renormalization group transformations are related to non-associative algebras. Non-trivial infrared fixed points are shown to be solutions of polynomial equations. At the example of a scalar model in $d(\ge2)$ dimensions some methods for the solution of these algebraic equations are presented.

Othmar Brodbeck, Norbert Straumann

We prove that static, spherically symmetric, asymptotically flat soliton and black hole solutions of the Einstein-Yang-Mills equations are unstable for arbitrary gauge groups, at least for the ``generic&#34; case. This conclusion is derived without explicit knowledge of the possible equilibrium solutions.

Ingemar Bengtsson

We give a Hamiltonian formulation of massive spin 2 theory in arbitrary Einstein space-times. We pay particular attention to Higuchi&#39;s forbidden mass range in deSitter space.

Denis Juriev

Some algebraic, geometric and geometroalgebraic characteristics of pairs of operators are discussed.

Johannes Huebschmann

Let $Σ$ be a closed surface, $G$ a compact Lie group, not necessarily connected, with Lie algebra $g$, endowed with an adjoint action invariant scalar product, let $ξ\colon P \to Σ$ be a principal $G$-bundle, and pick a Riemannian metric and orientation on $Σ$ so that the corresponding Yang-Mills equations are defined. In an earlier paper we determined the l

Johannes Huebschmann

Let $Σ$ be a closed surface, $G$ a compact Lie group, not necessarily connected, with Lie algebra $g$, endowed with an adjoint action invariant scalar product, let $ξ\colon P \to Σ$ be a principal $G$-bundle, and pick a Riemannian metric and orientation on $Σ$, so that the corresponding Yang-Mills equations $$d_A*K_A = 0$$ are defined, where $K_A$ refers to

J. M. P. Carmelo, N. M. R. Peres

Based on a recently introduced operator algebra for the description of a class of integrable quantum liquids we define the ground states for all canonical ensembles of these systems. We consider the particular case of the Hubbard chain in a magnetic field and chemical potential. The ground states of all canonical ensembles of the model can be generated by ac

M. L. Plumer, A. Mailhot

Histogram Monte-Carlo simulation results are presented for the magnetic-field -- temperature phase diagram of the Ising model on a stacked triangular lattice with antiferromagnetic intraplane and ferromagnetic interplane interactions. Finite-size scaling results for this frustrated system at three points along the paramagnetic transition boundary are present

R. Cote, L. Brey, H. Fertig, A. H. MacDonald

In strong perpendicular magnetic fields double-quantum-well systems can sometimes occur in unusual broken symmetry states which have interwell phase coherence in the absence of interwell hopping. When hopping is present in such systems and the magnetic field is tilted away from the normal to the quantum well planes, a related soliton-lattice state can occur

A. D. Rutenberg, A. J. Bray

We consider quenches in non-conserved two-dimensional XY systems between any two temperatures below the Kosterlitz-Thouless transition. The evolving systems are defect free at coarse-grained scales, and can be exactly treated. Correlations scale with a characteristic length $L(t) \propto t^{1/2}$ at late times. The autocorrelation decay exponent, $\barλ = (η

R. K. Bhaduri, M. V. N. Murthy, R. Shankar

It is proposed that the phenomenon of charge fractionalisation of the spatially confined particle in a topological chiral bag may be interpreted as a manifestation of the exclusion statistics proposed by Haldane. The fractional exclusion statistics parameter is just the fractional baryon charge $Q$ of the particle in this case. We also state the necessary co

Zoltan Neda

We study by Monte Carlo techniques the evolution of finite two-dimensional Ising systems in oscillating magnetic fields. The phenomenon of stochastic resonance is observed. The characteristic peak obtained for the correlation function between the external field and magnetization, versus the temperature of the system, is studied for various external fields an

Sandro Stringari

The formalism of density functional theory (DFT) can be easily extended to the time dependent case (TDDFT). However, while in the static case the theory is well established and is expected to be, at least in principle, an exact approach for the determination of energy and density profiles of inhomogeneous systems, the applicability of TDDFT to the investigat

Franco Dalfovo, Andrea Lastri, Sandro Stringari

We present a new density functional, which is the result of a natural evolution and improvement of previous density functional theories for liquid helium. We focus on the key ingredients of the theory, showing how they determine important predictions concerning inhomogeneous systems. These predictions turn out to be quite accurate even at the level of intera

A. F. Volkov, P. H. C. Magnée, B. J. van Wees, T. M. Klapwijk

The DC Josephson effect is theoretically studied in a planar junction in which a two dimensional electron gas (2DEG) infinite in lateral directions is in contact with two superconducting electrodes placed on top of the 2DEG. An energy gap in the excitation spectrum is created in the 2DEG due to the proximity effect. It is shown that under certain conditions,

Annie C. Robin, Michel Creze, Vijay Mohan

As part of a stellar population sampling program, a series of photometric probes at various field sizes and depths have been obtained in a low extinction window in the galactic anticentre direction. Very deep CCD frames probe the most external parts of the disc, providing strong evidence that the galactic density scale length for the old disc population is r

G. T. Gussie, A. R. Taylor, P. E. Dewdney, R. S. Roger

The dissociation and subsequent ionisation of molecular material in a detached, spherically symmetric stellar wind is modelled as a star evolves from the post-asymptotic giant branch phase to a planetary nebula (i.e. from a stellar effective temperature of Teff=6000K to Teff=33000K). The model is compared to the observed mass and distribution of ionised and

G. T. Gussie, A. R. Taylor

21cm spectral-line and continuum observations of ten compact planetary nebulae have been made with the Very Large Array. Circumnebular atomic hydrogen is identified in the planetary nebulae SwSt1, M3-35, and possibly in Hu2-1. The possibility of an inverse correlation between the optical depth of circumnebular atomic hydrogen and the linear radius of the ion

M. Szymanski, A. Udalski, J. Kaluzny, M. Kubiak

We present follow-up observations of a gravitational microlensing candidate found by the MACHO collaboration in the Galactic bulge. The photometric data cover a period near the maximum of the event and may be used to construct complete light curve. The position of the lensed star in the color magnitude diagram suggests that it is a Galactic bulge star locate

J. C. Miller, L. Rezzolla

Two previous papers in this series have presented a study of the growth of hadronic bubbles during the cosmological Quark--Hadron transition, treating the material within each phase as a single perfect fluid. Here, we extend the analysis to include the effects of long-range energy and momentum transfer by weakly and electromagnetically interacting particles.

JJ Kavelaars, David A. Hanes, Terry J. Bridges, William E. Harris

We present the results of a $BVI$ photometric study of the globular cluster NGC 6517 using CCD images obtained at the prime focus of the CFHT. From the resultant color-magnitude diagram, we infer that the cluster is differentially reddened and develop a method for determining the amplitude of this effect, which amounts to \( \sim 0.4 \) mag in \( (V-I) \) ac

Renee C. Kraan-Korteweg, Tony P. Fairall, Chantal Balkowksi

Spectroscopic observations have been carried out for galaxies in the Milky Way with the 1.9 m telescope of the South African Astronomical Observatory (SAAO). The galaxies were selected from a deep optical galaxy search covering 266<l<296 |b|<10deg. This is in the extension of the Hydra and Antlia clusters and in the approximate direction of the dipole anisot

C. Travier, L. Boy, J. N. Cayla, B. Leblond

The CANDELA photo-injector is a two cell S-band photo-injector. The copper cathode is illuminated by a 500 fs Ti:sapphire laser. This paper presents energy spectrum measurements of the dark current and intense electron emission that occurs when the laser power density is very high.

Stefan Cordes, Gregory Moore, Sanjaye Ramgoolam

These are expository lectures reviewing (1) recent developments in two-dimensional Yang-Mills theory, and (2) the construction of topological field theory Lagrangians. Topological field theory is discussed from the point of view of infinite-dimensional differential geometry. We emphasize the unifying role of equivariant cohomology both as the underlying prin

Abhay Ashtekar

After a brief chronological sketch of developments in non-perturbative canonical quantum gravity, some of the recent mathematical results are reviewed. These include: i) an explicit construction of the quantum counterpart of Wheeler&#39;s superspace; ii) a rigorous procedure leading to the general solution of the diffeomorphism constraint in quantum geometro

Morris L. Swartz

We reevaluate the hadronic part of the electromagnetic vacuum expectation value using the standard dispersion integral approach that utilizes the hadronic cross section measured in $\ee$ experiments as input. Previous analyses are based upon point-by-point trapezoidal integration which has the effect of weighting all inputs equally. We use a technique that w

J. Rameš

The behaviour of like-charge and unlike-charge second factorial moments in $e^+e^-$ reactions is discussed. It is argued that Monte Carlo calculation with the help of generators JETSET 7.4 and HERWIG 5.8 points to the conclusion that the only nontrivial cause of intermittency are Bose-Einstein correlations of identical particles.

Marco Guagnelli

We present data from the ALPHA Collaboration about lattice calculation of SU(2) pure--gauge running coupling constant, obtained with two different definitions of the coupling itself, which show universality of the continuum limit and clarify the applicability of renormalized perturbation theory.

J. Sladkowski

We investigate how exotic differential structures may reveal themselves in particle physics. The analysis is based on the A. Connes&#39; construction of the standard model. It is shown that, if one of the copies of the spacetime manifold is equipped with an exotic differential structure, compact object of geometric origin may exist even if the spacetime is t

S. Andreon, B. Garilli, D. Maccagni

Intrinsic color profiles of a sample of nine Brightest Cluster Galaxies (BCGs) are recovered from the observed color profiles by evaluating spurious gradients introduced by errors in the determination of the sky levels and by different seeing conditions between the observations. Isophote shapes and surface brightness profiles are presented for the four newly

J. A. Gomez Tejedor, E. Oset, H. Toki

We have studied the gamma d ---> Delta++ Delta- reaction which requires the collaboration of the two nucleons in deuteron. By means of a model previously developed for the gamma p ----> p pi+ pi- reaction, the two body exchange currents leading to double delta creation are derived. A fair agreement is obtained with a recent experiment, but more precise measu

Virach Sornlertlamvanich, Wantanee Pantachat, Surapant Meknavin

This paper presents an algorithm for selecting an appropriate classifier word for a noun. In Thai language, it frequently happens that there is fluctuation in the choice of classifier for a given concrete noun, both from the point of view of the whole spe ech community and individual speakers. Basically, there is no exect rule for classifier selection. As fa

Jungil Lee, J. S. Shim, H. S. Song

We derive the simplest form of the $κ(κ^2)$ order graviton self-interaction Lagrangian density $\lag{1}(\lag{2})$ in the weak field approximation. With the divergenceless condition, de Donder gauge and some combinatoric techniques, we derive the mathematically independent basis expressions for $\lag{1}(\lag{2})$ composed of 8(24) terms. By using the basis ex

H. C. Rosu

Short remarks on the problem of assigning frequency spectra to Casimir, sonoluminescence, Hawking, Unruh, and quantum optical squeezing effects are presented

G. Q. Li, C. M. Ko

In the relativistic transport model, we show that the recently observed enhancement of low-$m_t$ kaons ($K^+$ and $K^-$) in Si+Pb collisions at AGS can be explained if a density isomer is introduced in the nuclear equation-of-state.

Mark R. Pederson

Due to the overbinding that is inherent in existing {\em local} approximations to the density-functional formalism, certain reaction energies have not been accessible. Since the generalized gradient approximation significantly decreases the overbinding, prospects for density-functional-based reaction dynamics are promising. Results on the generalized-gradien

Dierk Schleicher

We describe an interesting interplay between symbolic dynamics, the structure of the Mandelbrot set, permutations of periodic points achieved by analytic continuation, and Galois groups of certain polynomials. Internal addresses are a convenient and efficient way of describing the combinatorial structure of the Mandelbrot set, and of giving geometric meaning

Tom H. Koornwinder

In this paper I present a brief survey of the active area of Special Functions associated with Root Systems. The article is intended for a general mathematical audience. It will not suppose prerequisites on either special functions or root systems. It will also skip many technical details. Some early work in this area (root systems BC_2 and A_2) was done by

Dharma P. Gupta, Mourad E. H. Ismail, David R. Masson

Explicit solutions for the three-term recurrence satisfied by associated continuous dual $q$-Hahn polynomials are obtained. A minimal solution is identified and an explicit expression for the related continued fraction is derived. The absolutely continuous component of the spectral measure is obtained. Eleven limit cases are discussed in some detail. These i

M. A. De Andrade

Spinors for an arbitrary Minkowski space with signature ($t$, $s$) are reassessed in connection with $D$-dimensional free Dirac action. The possibility of writing down kinetic and mass terms for charge-conjugated spinors is discussed in terms of the number of time-like directions of the space-time.

M. A. De Andrade, O. M. Del Cima

In this letter, we present the action for the massive super-{\QED}. A pair of chiral and a pair of anti-chiral superfields with opposite U(1)-charges are required. We also carry out a dimensional reduction {\it{à la}} Scherk from (2+2) to (1+2) dimensions, and we show that, after suitable truncations are performed, the supersymmetric extension of the $τ_{3}$

S. Mignemi

We consider two-dimensional dilaton-gravity theories with a generic exponential potential for the dilaton, and obtain the most general black hole solutions in the Schwarzshild form. We discuss their geometrical and thermodynamical properties. We also study these models from the point of view of gauge theories of the extended Poincaré group and show that they

Adriá n R. Lugo

We consider gauged Wess-Zumino models based on the non compact group $SU(2,1)$. It is shown that by vector gauging the maximal compact subgroup $U(2)$ the resulting backgrounds obey the gravity-dilaton one loop string vacuum equations of motion in four dimensional euclidean space. The torsionless solution is then interpreted as a pseudo-instanton of the $d=4

I. N. McArthur

Berkovits and Vafa recently showed that critical string theories can be considered as critical superstring theories with a special choice of background. The embedding of the Virasoro algebra into the super-Virasoro algebra involved in this construction has been extended to the noncritical case by Berkovits and Ohta. It is shown that the resulting nonlinear r

Arjun Berera

The triple gluon-ladder vertex is shown to project the outgoing gluon in either polarization state with equal probability up to the leading double-ln(x)ln($Q^2$) approximation. This implies that the $Q^2$-evolution of $ΔG (x, Q^2)$ is free from recombination effects to this level of approximation.

James D. Bjorken

Summary talk given at the 24th International Symposium on Multiparticle Dynamics, Italy, September 1994 -- This summary talk only reviews a small sample of topics featured at this symposium: 1. Introduction 2. The Geometry and Geography of Phase space 3. Space-Time Geometry and HBT 4. Multiplicities, Intermittency, Correlations 5. Disoriented Chiral Condensa