October 1998 arXiv papers

Jounghun Lee, Sergei F. Shandarin

We present numerical testing results of our mass function derived in our previous paper, and compare the testing results with those of the popular Press-Schechter (PS) mass function. Two fiducial models are considered for the test: the scale-free power-law spectra P(k) \propto k^{n} with spectral indices n=-1, 0 and the standard cold dark matter (SCDM) model

A. Pablo, L. Barbero, Hugo E. Hernandez F., Erasmo Recami

The group-velocity of evanescent waves (in undersized waveguides, for instance) was theoretically predicted, and has been experimentally verified, to be Superluminal (v_g > c). By contrast, it is known that the precursor speed in vacuum cannot be larger than c. In this paper, by computer simulations based on Maxwell equations only, we show the existence of b

Angel M. Uranga

We study the T duality between a set of type IIB D3 branes atnon-orbifold threefold singularities, and type IIA configurations of D4 branes stretched between relatively rotated NS fivebranes. The four-dimensional N=1 field theories on the D3 brane world-volume can be easily described using the IIA brane configuration. These models include families of chiral

Paolo Nason, Carlo Oleari

We use a recently completed O(alpha_s^2) fixed-order calculation of the heavy-flavour production cross section in e+e- collisions to compute the heavy-quark fragmentation function. We fit the result of our calculation, convoluted with a Peterson fragmentation function, to available data for charm production, and thus obtain a value for the parameter epsilon

Katsushi Ito

We study a supersymmetric extension of the Virasoro algebra on the boundary of the anti-de Sitter space-time AdS_{3}. Using the free field realization of the currents, we show that the world-sheet affine Lie superalgebras osp(1|2)^{(1)}, sl(1|2)^{(1)} and sl(2|2)^{(1)} provide the boundary N=1,2 and 4 extended superconformal algebras, respectively.

Darwin Chang, Wai-Yee Keung, Apostolos Pilaftsis

We calculate a new type of two-loop contributions to the electric dipole moments of the electron and neutron in supersymmetric theories. The new contributions are originated from the potential CP violation in the trilinear couplings of the Higgs bosons to the scalar-top or the scalar-bottom quarks. These couplings were previously very weakly constrained. The

Eung Jin Chun, Jae Sik Lee

R-parity violating bilinear (soft) terms in the supersymmetric standard model would be the leading source for nonzero neutrino masses and mixing. We point out that the mixing between neutralinos (charginos) and neutrinos (charged leptons) driven by the bilinear terms take factorized forms, which may enable us to probe the neutrino mixing parameters in a coll

Zhigang Zheng, Gang Hu, Bambi Hu

The behaviors of coupled oscillators, each of which has periodic motion with random natural frequency in the absence of coupling, are investigated. Some novel collective phenomena are revealed. At the onset of instability of the phase-locking state, simultaneous phase slips of all oscillators and quantized phase shifts in these phase slips are observed. By i

Shuichi Murakami, Naoto Nagaosa, Manfred Sigrist

We study an SO(5) model unifying p-wave superconductivity and ferromagnetism. If only a single p-wave pairing wavefunction is involved, the p-wave superconducting (pSC) and ferromagnetic (F) states can be unified to form 10-dimensional multiplet of SO(5). The collective modes in pSC and F states are studied from this viewpoint in terms of a non-linear sigma

S. M. Sergeev

A quantum evolution model in 2+1 discrete space - time, connected with 3D fundamental map R, is investigated. Map R is derived as a map providing a zero curvature of a two dimensional lattice system called "the current system". In a special case of the local Weyl algebra for dynamical variables the map appears to be canonical one and it corresponds t

S. M. H. Wong

The approach of a parton plasma at future heavy ion colliders towards kinetic and chemical equilibrium is considered. A plasma with a self-consistent evolving parton-parton interaction strength is shown to equilibrate better and faster than the usual but inconsistent one with a fixed strength. We explain why as a consequence of this, a parton plasma is a uni

S. L. Lyakhovich, A. A. Sharapov, K. M. Shekhter

The general model of an arbitrary spin massive particle in any dimensional space-time is derived on the basis of Kirillov - Kostant - Souriau approach. Keywords: spinning particles, Poincaré group, orbit method, constrained dynamics, geometric quantization.

A. Bogojevic, B. Sazdovic, O. Miskovic

We look at the equivalence of the massive Thirring and sine-Gordon models. Previously, this equivalence was derived perturbatively in mass (though to all orders). Our calculation goes beyond that and uncovers an underlying conformal symmetry.

Chun Liu, H. S. Song

A supersymmetric model which naturally accommodates MeV tau neutrino within the framework of gauge mediated supersymmetry breaking is described. The lepton number violation is originally introduced in the messenger sector of the theory. A large slepton-Higgs mixing mass and a small lepton-higgsino mixing mass are generated at one-loop. Scalar tau neutrino ha

J. Engelfried, I. Filimonov, J. Kilmer, A. Kozhevnikov

In this article, construction, operation, and performance of the RICH detector of Fermilab experiment 781 (SELEX) are described. The detector utilizes a matrix of 2848 phototubes for the photocathode to detect Cherenkov photons generated in a 10m Neon radiator. For the central region an N0 of 104/cm, corresponding to 13.6 hits on a beta=1 ring, was obtained.

Andrew R. Golding, Dan Roth

A large class of machine-learning problems in natural language require the characterization of linguistic context. Two characteristic properties of such problems are that their feature space is of very high dimensionality, and their target concepts refer to only a small subset of the features in the space. Under such conditions, multiplicative weight-update

Serguei P. Tsarev

Using a new definition of generalized divisors we prove that the lattice of such divisors for a given linear partial differential operator is modular and obtain analogues of the well-known theorems of the Loewy-Ore theory of factorization of linear ordinary differential operators. Possible applications to factorized Groebner bases computations in the commuta

Lunjin Lu

A polymorphic analysis is an analysis whose input and output contain parameters which serve as placeholders for information that is unknown before analysis but provided after analysis. In this paper, we present a polymorphic groundness analysis that infers parameterised groundness descriptions of the variables of interest at a program point. The polymorphic

V. Yu. Irkhin, Yu. P. Irkhin

An analysis of magnetic anisotropy in RCo5 compounds is performed with account of screening of ion point charges by conduction electrons. A crucial role of non-uniform distribution of screening electrons (the terms containing derivatives of charge density) is demonstrated. Influence of anisotropy of screening, that is connected with the anisotropy of the Fer

V. Yu. Irkhin, A. A. Katanin

The two-dimensional (2D) Heisenberg magnet with a weak easy-plane anisotropy is considered. A renormalization group (RG) analysis in this model is performed for both quantum and classical cases. A crossover from the Heisenberg to 2D XY model is discussed. The magnetic transition owing to the interlayer coupling is considered. Analytical results for the Koste

Ryoichi Yamamoto, Akira Onuki

The diffusivity of tagged particles is demonstrated to be heterogeneous on time scales comparable to or less than the structural relaxation time %taking place at the interparticle distance in a highly supercooled liquid via 3D molecular dynamics simulation. The particle motions in the relatively active regions dominantly contribute to the mean square displac

A. C. Goncalves, P. Veron, M. -P. Veron-Cetty

We present results based on the analysis of optical spectra of KUG 1031+398, a Narrow Line Seyfert 1 (NLS1) galaxy for which Mason et al. (1996) reported evidence for a line-emitting region "intermediate" (both in terms of velocity and density) between the conventional broad and narrow line regions (BLR and NLR, respectively). From our observations a

Giorgio Matt

I discuss the advances in our understanding of the physics and morphology of the innermost regions of AGNs which will be possible thanks to the XMM unprecedented sensitivity and its moderate to high energy resolution.

Rachel S. Somerville, Joel R. Primack

Observations now probe the star formation history of the Universe back to a redshift of $z\sim5$. We investigate whether the predictions of semi-analytic models of galaxy formation based on hierarchical Cold Dark Matter (CDM) type models are in agreement with these direct observations and also with the ``fossil'' evidence contained in constraints on

Roelof S. de Jong, Cedric Lacey

The local space density of galaxies as a function of their basic structural parameters --like luminosity, surface brightness and scalesize-- is still poorly known. Our poor knowledge is mainly the result of strong selection biases against low surface brightness and small scalesize galaxies in any optically selected sample. We show that in order to correct fo

Micha Berkooz, Anton Kapustin

We present nontrivial examples of d=3 gauge theories with sixteen and eight supercharges which are infrared dual at special points in the moduli space. This duality is distinct from mirror symmetry. To demonstrate duality we construct the gauge theories of interest using D2-branes and orientifolds and then consider their lift to M-theory. We also discuss the

Shoichi Ichinose, Noriaki Ikeda

An algorithm to obtain the Weyl anomaly in higher dimensions is presented. It is based on the heat-kernel method. Feynman rules, such as the vertex rule and the propagator rule, are given in (regularized) coordinate space. Graphical calculation is introduced. The 6 dimensional scalar-gravity theory is taken as an example, and its explicit result is obtained.

Ken Kiers, Amarjit Soni, Guo-Hong Wu

We explore charged-Higgs CP-violating effects in an intriguing two-Higgs doublet model which accords special status to the top quark. In this model the heaviness of the top quark originates naturally from the much larger VEV of the second Higgs doublet compared to that of the first. The phenomenology of this model is quite distinct from that of the usual for

Andreas Karch, Dieter Lust, Andre Miemiec

In this paper we discuss the strong coupling limit of chiral N=1 supersymmetric gauge theory via their embedding into M-theory. In particular we focus on the brane box models of Hanany and Zaffaroni and show that after a T-duality transformation their M-theory embedding is described by supersymmetric 3-cycles; its geometry will encode the holomorphic non-per

Alexei Vazquez, Oscar Sotolongo-Costa

A sandpile model with stochastic toppling rule is studied. The control parameters and the phase diagram are determined through a MF approach, the subcritical and critical regions are analyzed. The model is found to have some similarities with directed percolation, but the existence of different boundary conditions and conservation law leads to a different un

F. Berto, J. L. Domenech, M. A. Sanchis-Lozano

We derive a tree-level heavy quark effective Lagrangian keeping particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair annihilation and creation. However, when removing the unwanted degrees of freedom from the effective Lagrangian one has to be careful in using the classical equations of motion obeyed by the effective fields in order to

Lapo Casetti, E. G. D. Cohen, Marco Pettini

We argue that the phase transition in the mean-field XY model is related to a particular change in the topology of its configuration space. The nature of this topological transition can be discussed on the basis of elementary Morse theory using the potential energy per particle V as a Morse function. The value of V where such a topological transition occurs

Mariano Cadoni, Salvatore Mignemi

We present a microscopical derivation of the entropy of the black hole solutions of the Jackiw-Teitelboim theory. We show that the asymptotic symmetry of two-dimensional (2D) Anti-de Sitter space is generated by a central extension of the Virasoro algebra. Using a canonical realization of this symmetry and Cardy's formula we calculate the statistical entropy

A. Cavaliere, N. Menci, P. Tozzi

We develop a model to describe the evolution of the intra-cluster X-ray emitting baryons, as they are included in the dark matter potential wells of galaxy clusters evolving through subsequent merging events in the framework of hierarchical clustering. The gas is assumed to re-adjusts to a new hydrostatic equilibrium after each merging event. Before merging

G. Bottazzi, G. Marchesini, G. P. Salam, M. Scorletti

This article presents the results of a quantitative study of the small-x data at HERA, using the CCFM equation. The first step consists of choosing the version of the CCFM equation to be used, corresponding to selecting a particular subset of next-to-leading-logarithmic corrections --- the choice is constrained by requiring a phenomenologically reasonable sm

Mark D. Roberts

For any given spacetime the choice of time coordinate is undetermined. A particular choice is the absolute time associated with a preferred vector field. Using the absolute time Hamilton's equations are $- (δH_{c})/(δq)=\dotπ+Θπ, $+ (δH_{c})/(δπ)=\dot{q}$, where $Θ= V^{a}_{.;a}$ is the expansion of the vector field. Thus there is a hitherto unnoticed ter

Ehab Malkawi

We propose and study a common hierarchical mass texture for both charged lepton and neutrino sectors. The texture gives rise to a large $ν_μ\leftrightarrowν_τ$ mixing. Also it leads to the small angle MSW effect solution for solar neutrino data. It naturally gives a small $ν_e\leftrightarrow ν_τ$ oscillation relevant to the CHOOZ result in certain mass limit

D. V. Shirkov

The structure of the QFT expansion is studied in the framework of a new "Invariant analytic" version of the perturbative QCD. Here, an invariant (running) coupling $a(Q^2/Λ^2)=β_1α_s(Q^2)/4π$ is transformed into a "$Q^2$--analytized" invariant coupling $a_{\rm an}(Q^2/Λ^2) \equiv {\cal A}(x)$ which, by constuction, is free of ghost singularit

Hee-Jung Lee, Dong-Pil Min, Byung-Yoon Park, Mannque Rho

The flavor singlet axial charge has been a source of study in the last years due to its relation to the so called {\it Proton Spin Problem}. The relevant flavor singlet axial current is anomalous, i.e., its divergence contains a piece which is the celebrated $U_A(1)$ anomaly. This anomaly is intimately associated with the $η^\prime$ meson, which gets its mas

Hiroo Azuma

We discuss how to build some partially entangled states of $n$ two-state quantum systems (qubits). The optimal partially entangled state with a high degree of symmetry is considered to be useful for overcoming a shot noise limit of Ramsey spectroscopy under some decoherence. This state is invariant under permutation of any two qubits and inversion between th

Kyungho Oh, Radu Tatar

Recently it was conjectured that parallel branes at conical singularities are related to string/M theory on $AdS \times X$ where $X$ is an Einstein manifold. In this paper we consider coincident M2 branes near a conifold singularity when M theory is compactified on $AdS_4 \times Q^{1,1,1}$ where $Q^{1,1,1} = (SU(2) \times SU(2) \times SU(2))/(U(1) \times U(1

N. Dorey, T. J. Hollowood, V. V. Khoze, M. P. Mattis

We examine certain n-point functions G_n in {\cal N}=4 supersymmetric SU(N) gauge theory at the conformal point. In the large-N limit, we are able to sum all leading-order multi-instanton contributions exactly. We find compelling evidence for Maldacena's conjecture: (1) The large-N k-instanton collective coordinate space has the geometry of AdS_5 x S^5.

Yuval Grossman, Howard E. Haber

R-parity-violating supersymmetry (with a conserved baryon number B) provides a framework for particle physics with lepton number (L) violating interactions. We examine in detail the structure of the most general R-parity-violating (B-conserving) model of low-energy supersymmetry. We analyze the mixing of Higgs bosons with sleptons and the mixing of charginos

O. G. Balev, P. Vasilopoulos

A random-phase approximation (RPA) treatment of edge magnetoplasmons (EMP) is presented for strong magnetic fields, low temperatures, and integer filling factors ν. It is valid for negligible dissipation and lateral confining potentials smooth on the scale of the magnetic length \ell_{0} but sufficiently steep that the Landau-level (LL) flattening can be neg

A. Lima-Santos, I. Roditi, A. Foerster

A recently proposed strongly correlated electron system associated with the Temperley-Lieb algebra is solved by means of the coordinate Bethe ansatz for periodic and closed boundary conditions.

K. Iohara, Y. Saito, M. Wakimoto

In this note, we compute Hirota bilinear forms arising from both homogeneous and principal realization of vertex representations of 2-toroidal Lie algebras of type $A_l, D_l, E_l$.

W. Geist, L. You, T. A. B. Kennedy

Sympathetic cooling of an atomic Fermi gas by a Bose gas is studied by solution of the coupled quantum Boltzmann equations for the confined gas mixture. Results for equilibrium temperatures and relaxation dynamics are presented, and some simple models developed. Our study illustrate that a combination of sympathetic and forced evaporative cooling enables the

Y. N. Srivastava, G. Vitiello, A. Widom

In order to understand the Landau-Lifshitz conjecture on the relationship between quantum measurements and the thermodynamic second law, we discuss the notion of ``diabatic'' and ``adiabatic'' forces exerted by the quantum object on the classical measurement apparatus. The notion of heat and work in measurements is made manifest in this appro

R. W. Spekkens, J. E. Sipe

We present a theoretical study of the ground state of a Bose-Einstein condensate with repulsive inter-particle interactions in a double-well potential, using a restricted variational principle. Within such an approach, there is a transition from a single condensate to a fragmented condensate as the strength of the central barrier of the potential is increase

Jonathan D. Victor, Keith P. Purpura

We present the mathematical basis of a new approach to the analysis of temporal coding. The foundation of the approach is the construction of several families of novel distances (metrics) between neuronal impulse trains. In contrast to most previous approaches to the analysis of temporal coding, the present approach does not attempt to embed impulse trains i

Richard F. Lebed

These lectures are designed to introduce the methods and results of large N_c QCD in a presentation intended for nuclear and particle physicists alike. Beginning with definitions and motivations of the approach, we demonstrate that all quark and gluon Feynman diagrams are organized into classes based on powers of 1/N_c. We then show that this result can be t

J. Carbonell, V. A. Karmanov

The deuteron form factors are calculated in the framework of the relativistic nucleon-meson dynamics. The relativistic effects change considerably the S- and D-waves of the deuteron, result in the dominating extra component in the deuteron wave function and generate the contact interaction between the nucleon, mesons and photon. The prediction for the polari

Gerhard Baur, Kai Hencken, Dirk Trautmann

In central collisions at relativistic heavy ion colliders like the Relativistic Heavy Ion Collider RHIC/Brookhaven and the Large Hadron Collider LHC (in its heavy ion mode) at CERN/Geneva, one aims at detecting a new form of hadronic matter --- the Quark Gluon Plasma. We discuss here a complementary aspect of these collisions, the very peripheral ones. Due t

Rene Bellwied

With the advent of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), Heavy Ion Physics will enter a new energy regime. The question is whether the signatures proposed for the discovery of a phase transition from hadronic matter to a Quark Gluon Plasma (QGP), that were established on the basis of collisions at the BEVALAC, th

The JLAB t20 collaboration, D. Abbott

The A(Q^2) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q^2 between 0.66 and 1.80 (GeV/c)^2 in Hall C at Jefferson Laboratory. The scattered electrons and recoil deuterons were detected in coincidence, at a fixed deuteron angle of 60.5 degrees. These new precise measurements resolve discrepancies between o

Mahan Mitra

This paper is a survey of some of the developments in coarse extrinsic geometry since its inception in the work of Gromov. Distortion, as measured by comparing the diameter of balls relative to different metrics, can be regarded as one of the simplist extrinsic notions. Results and examples concerning distorted subgroups, especially in the context of hyperbo

Anders S. Buch

In this exposition we give a simple and complete treatment of A. Knutson and T. Tao's recent proof (http://front.math.ucdavis.edu/math.RT/9807160) of the saturation conjecture, which asserts that the Littlewood-Richardson semigroup is saturated. The main tool is Knutson and Tao's hive model for Berenstein-Zelevinsky polytopes. In an appendix of W. Fu

Andrzej Roslanowski, Saharon Shelah

We consider the following property: (*) For every function f from R^2 to R there are functions g_n,h_n from R to R (for n<omega) such that for all real numbers x and y, f(x,y) = sum_{n<omega} g_n(x)h_n(y). We show that, despite some expectation suggested by [Sh:675], (*) does not imply MA(sigma-centered). Next, we introduce cardinal characteristics of the co

Lee S. Nave

Let p be a prime. The Smith-Toda complex V(k) is a finite spectrum whose BP-homology is isomorphic to BP_*/(p,v_1,...,v_k). For example, V(-1) is the sphere spectrum and V(0) the mod p Moore spectrum. In this paper we show that if p > 5, then V((p+3)/2) does not exist and V((p+1)/2), if it exists, is not a ring spectrum. The proof uses the new homotopy fixed

Julian Dontchev

The aim of this survey article is to cover most of the recent research on preopen sets. I try to present majority of the results on preopen sets that I am aware of.

Julian Dontchev, Takashi Noiri

Recently, Saleh claimed to have solved `a long standing open question&#39; in Topology; namely, he proved that every almost continuous function is closure continuous (= $θ$-continuous). Unfortunately, this problem was settled long time ago and even a better result is known.

Julian Dontchev, Maximilian Ganster

The aim of this paper is to continue the study of sg-compact spaces. The class of sg-compact spaces is a proper subclass of the class of hereditarily compact spaces. In our paper we shall consider sg-compactness in product spaces. Our main result says that if a product space is sg-compact, then either all factor spaces are finite, or exactly one factor space

C. Faber, R. Pandharipande

Integrals of the Chern classes of the Hodge bundle in Gromov-Witten theory are studied. We find a universal system of differential equations which determines the generating function of these integrals from the standard descendent potential (for any target X). We use virtual localization and classical degeneracy calculations to find trigonometric closed form

C. Gonera, P. Kosinski

The Calogero model with external harmonic oscillator potential is discussed from sL(2,R) algebra point of view. Explicit formulae for functions with exponential time behaviour are given; in particular, the integrals of motion are constructed and their involutiveness demonstrated. The superintegrability of the model appears to be a simple consequence of the f

Z. Chacko, Markus A. Luty, Eduardo Ponton

We consider models of dynamical supersymmetry breaking in which the extremization of a tree-level superpotential conflicts with a quantum constraint. We show that in such models the low-energy effective theory near the origin of moduli space is an O&#39;Raifeartaigh model, and the sign of the mass-squared for the pseudo-flat direction at the origin is calcul

A. Pashnev, M. Tsulaia

The method of the BRST quantization is considered for the system of constraints, which form a Lie algebra. When some of the Cartan generators do not imply any conditions on the physical states, the system contains the first and the second class constraints. After the introduction auxiliary bosonic degrees of freedom for these cases, the corresponding BRST ch

Charles P. Boyer, Krzysztof Galicki

This is an expository paper describing the geometry of certain Sasakian-Einstein manifolds. Such manifolds have recently become of interest due to Maldacena&#39;s AdS/CFT conjecture. They describe near-horizon geometries of branes at conical singularities.

H. Fort, E. Marino

A full quantum description of global vortex strings is presented in the framework of a pure Higgs system with a broken global U(1) symmetry in 3+1D. An explicit expression for the string creation operator is obtained, both in terms of the Higgs field and in the dual formulation where a Kalb-Ramond antisymmetric tensor gauge field is employed as the basic fie

K. Splittorff

Universality in unitary invariant random matrix ensembles with complex matrix elements is considered. We treat two general ensembles which have a determinant factor in the weight. These ensembles are relevant, e.g., for spectra of the Dirac operator in QCD. In addition to the well established universality with respect to the choice of potential, we prove tha

Zahid Zakir

In the method of thermostring quantization the time evolution of point particles at finite temperature kT is described in a geometric manner. The temperature paths of particles are represented as closed (thermo)strings, which are swept surfaces in space-time-temperature manifold. The method makes it possible a new physical interpretation of superstrings IIA

Chiang-Mei Chen

Starting with the 2+1 Einstein--Maxwell--Dilaton system with a cosmological constant and assuming two commuting Killing symmetries we derive the corresponding $1+0 σ$--model. It is shown that, for general values of the coupling parameters, the $T$--duality group is $SL(2,R)$, which coincides with the group of linear coordinate transformations along the Killi

A. Gomez Nicola, R. J. Rivers, D. A. Steer

We study bosonisation in the massive Thirring and sine-Gordon models at finite temperature and nonzero fermion chemical potential. Both canonical operator and path integral approaches are used to prove the equality of the partition functions of the two models at finite $T$ and zero chemical potential, as it has been recently shown. This enables the relations

Pierre Binetruy

We study several models of relevance for the dynamical breaking of supersymmetry which could provide a scalar component with equation of state $p=wρ$, $-1<w<0$. Such models would provide a natural explanation for recent data on the cosmological parameters.

P. Marage

Diffraction studies at HERA are introduced, with reference to other communications to this Conference. Motivations and specific features of the experimental approaches are stressed.

F. Ferrer, M. Nowakowski

In certain mild extensions of the Standard Model, spin-independent long range forces can arise by exchange of two very light pseudoscalar spin--0 bosons. In particular, we have in mind models in which these bosons do not have direct tree level couplings to ordinary fermions. Using the dispersion theoretical method, we find a $1/r^{3}$ behaviour of the potent

Xiaofeng Guo, Jianwei Qiu

We show that when Bjorken $x_B$ is large, the leading order twist-four contributions to the structure functions can be expressed in terms of the derivatives of the normal twist-two parton distributions. Our analytical results are not only consistent with the parameterized power corrections extracted from the data, but also predict the flavor dependence of th

Miguel A. Sanchis-Lozano

Charmonia hadro- and photo-production are analyzed in the framework of the color-octet model taking into account higher-order effects induced by initial-state radiation of gluons. We argue that color-octet matrix elements obtained from Tevatron data might be reconciled with those extracted from HERA data on inelastic $J/ψ$ photoproduction. Finally we estimat

A. Bialas, K. Zalewski

Local fluctuations of pion density in momentum space may lead to Bose-Einstein condensation. Conditions for this phenomenon to occur in in high-energy collisions and possibilities of its experimental investigation are discussed.

Wolfgang Ochs

The production of gluons in a jet is considered in limited phase space, either with a cut in transverse momentum with respect to the jet axis $k_\perp<k_\perp^{cut}$ or with a cut in absolute momentum $|\vec{k} | <k^{cut}$. It is shown in the perturbative QCD calculations that in the soft limit $k_\perp^{cut} \to 0$ the multiplicity distribution becomes Pois

M. Zralek

The problem of particle oscillation is considered in a pedagogical and comprehensive way. Examples from K, B and neutrino physics are given. Conceptual difficulties of the traditional approach to particle oscillation are discussed. It is shown how the probability current density and the wave packet treatments of particle oscillations resolve some problems. I

Antonio Dobado, Antonio L. Maroto

Torsion appears in a natural way in modern formulations of the gravitational theories. In this work we study several aspects of the interplay between the Standard Model and a classical gravitational background with torsion. In particular we consider the problem of the gauge and gravitational anomalies, $B$ and $L$ anomalies, the effective action for the tors

Y. S. Kim

The difference between Lorentz invariance and Lorentz covariance is discussed in detail. A covariant formalism is developed for the internal space-time symmetry of extended particles, especially in connection with the insightful observations Feynman made during the period 1969-72. A Lorentz-group formalism is presented for the harmonic oscillator model of Fe

K. -I. Izawa, M. Kawasaki, T. Yanagida

We propose a topological inflation model in the framework of supergravity with $R$ invariance. This topological inflation model is not only free from the initial value problem of the inflaton field but also gives low reheating temperature which is favored in supergravity since the overproduction of gravitinos is avoided. Furthermore, the predicted spectrum o

B. L. Ioffe, A. Oganesian

The part of the proton spin $Σ$ carried by $u, d, s$ quarks is calculated in the framework of the QCD sum rules in the external fields. The operators up to dimension 9 are accounted. An important contribution comes from the operator of dimension 3, which in the limit of massless $u, d, s$ quarks is equal to the derivative of QCD topological susceptibility $χ

F. Karsch, M. Oevers, A. Patkos, P. Petreczky

The screening masses of hot SU(N) gauge theory, defined as poles of the corresponding propagators are studied in 3d adjoint Higgs model, considered as an effective theory of QCD, using coupled gap equations and lattice Monte-Carlo simulations (for N=2). Using so-called lambda gauges non-perturbative evidence for gauge independence of the pole masses within t

Marek Gazdzicki, Mark I. Gorenstein

A statistical model of the early stage of central nucleus--nucleus (A+A) collisions is developed. We suggest a description of the confined state with several free parameters fitted to a compilation of A+A data at the AGS. For the deconfined state a simple Bag model equation of state is assumed. The model leads to the conclusion that a Quark Gluon Plasma is c

A. Hasenfratz, C. Nieter

We study the topological content of the SU(3) vacuum using a method based on RG mapping developed for SU(2) gauge theory earlier. RG mapping, in which a series of APE-smearing steps is done while tracking the observables, reduces the short range fluctuations in the gauge fields while preserving the long structure. This allows us to study the instanton size d

M. N. Chernodub

It is shown that the SU(2) Higgs model on a lattice is equivalent to the Georgi--Glashow model in the limit of a small coupling constant between the Higgs and gauge fields. It can therefore be concluded that the transition between the confinement and symmetric phases in the 3+1 dimensional SU(2) Higgs model at finite temperature is accompanied by condensatio

G. Braun, H. Fischer, J. Franz, A. Grunemaier

A new TDC-chip is under development for the COMPASS experiment at CERN. The ASIC, which exploits the 0.6 micrometer CMOS sea-of-gate technology, will allow high resolution time measurements with digitization of 75 ps, and an unprecedented degree of flexibility accompanied by high rate capability and low power consumption. Preliminary specifications of this n

ALEPH Collaboration

Radiative returns to the Z resonance (Zgamma events) provide a method to determine the centre-of-mass energy of the high energy e+e- colliders and already at LEP2. The method is applied for the data collected with the ALEPH detector in 1997 at 181-184 GeV, using e+e- -> gammaZ -> hadrons events.

Mark D. Roberts

A perfect fluid is quantized by the canonical method. The constraints are found and this allows the Dirac brackets to be calculated. Replacing the Dirac brackets with quantum commutators formally quantizes the system. There is a momentum operator in the denominator of some coordinate quantum commutators. It is shown that it is possible to multiply throughout

Michael Tsamparlis, Dimitris Nikolopoulos, Pantelis S. Apostolopoulos

The conformal algebra of a 1+3 decomposable spacetime can be computed from the conformal Killing vectors (CKV) of the 3-space. It is shown that the general form of such a 3-CKV is the sum of a gradient CKV and a Killing or homothetic 3-vector. It is proved that spaces of constant curvature always admit such conformal Killing vectors. As an example, the compl

A. Koga, S. Kumada, N. Kawakami

We investigate low-energy properties of two-dimensional quantum spin systems with the ladder and plaquette structures, which are described by a generalized antiferromagnetic Heisenberg model with both of the bond and spin alternations. By exploiting a non-linear $σ$ model technique and a modified spin wave approach, we evaluate the spin gap and the spontaneo

M. W. Jack, M. Naraschewski, M. J. Collett, D. F. Walls

The regions of validity of the Markov approximation for the coupling of atoms out of an atomic trap are determined. We consider radio-frequency output coupling in the presence of gravity and collisional repulsion, and Raman output coupling. The Markov approximation is crucial in most theoretical descriptions of an atom laser that assume a continuous process

Shan-Ho Tsai, Silvio R. A. Salinas

Fourth-order cumulants of physical quantities have been used to characterize the nature of a phase transition. In this paper we report some Monte Carlo simulations to illustrate the behavior of fourth-order cumulants of magnetization and energy across second and first-order transitions in the phase diagram of a well known spin-1 Ising model. Simple ideas fro

Douglas Davidson, Marcel den Nijs

The equilibrium crystal shape of a body-centered solid-on-solid (BCSOS) model on a honeycomb lattice is studied numerically. We focus on the facet ridge endpoints (FRE). These points are equivalent to one dimensional KPZ-type growth in the exactly soluble square lattice BCSOS model. In our more general context the transfer matrix is not stochastic at the FRE

S. H. Chun, M. B. Salamon, P. D. Han

The Hall resistivity rho_{xy} of a La_{2/3}(Ca,Pb)_{1/3}MnO_3 single crystal has been measured as a function of temperature and field. The overall behavior is similar to that observed previously in thin-films. At 5 K, rho_{xy} is positive and linear in field, indicating that the anomalous contribution $R_S$ is negligible. However, the effective carrier densi

M. Steinberg, J. Ortner

The high-density electron gas in a strong magnetic field B and at zero temperature is investigated. The quantum strong-field limit is considered in which only the lowest Landau level is occupied. It is shown that the perturbation series of the ground-state energy can be represented in analogy to the Gell-Mann Brueckner expression of the ground-state energy o

U. Leonhardt, P. Piwnicki

A classical dielectric moving in a charged capacitor can create a magnetic field (Roentgen effect). A quantum dielectric, however, will not produce a magnetization, except at vortices. The magnetic field outside the quantum dielectric appears as the field of quantized monopoles.

Aernout C. D. van Enter

We review what we have learned about the &#34;Renormalization-Group peculiarities&#34; which were discovered about twenty years ago by Griffiths and Pearce, and which questions they asked are still widely open. We also mention some related developments.