October 1995 arXiv papers — page 2

S. R. Shannon, T. C. Choy, R. J. Fleming

Writing $<R^2_N > = AN^{2ν}(1+BN^{-Δ_1}+CN^{-1}+ ...)$ for the mean square end--to--end length $<R^2_N>$ of a self--avoiding polymer chain of $N$ links, we have calculated $Δ_1$ for the two--dimensional {\em continuum} case from a new {\em finite} perturbation method based on the ground state of Edwards self consistent solution which predicts the (exact) $ν=

J. C. Hargreaves, G. Gilmore, J. D. Annan

We have completed a Monte-Carlo simulation to estimate the effect of binary star orbits on the measured velocity dispersion in dwarf spheroidal galaxies. This paper analyses previous attempts at this calculation, and explains the simulations which were performed with mass, period and ellipticity distributions similar to that measured for the solar neighbourh

Jason S. Best, Jane C. Charlton, Gottfried Mayer-Kress

In this paper we explore the application of the pointwise dimension (PD) analysis as a large-scale structure descriptor to the RC3 catalog of galaxies (de Vaucouleurs et al. 1991). This technique, which originated in the field of fractal geometry (Mandelbrot 1983) and found many applications in non-linear dynamics, is particularly illuminating in the study o

David Merritt

Estimation of the distribution function f and potential Phi of hot stellar systems from kinematical data is discussed. When the functional forms of f and Phi are not specified a priori, accurate estimation of either function requires very high quality data: either accurate ``line profiles&#39;&#39; at radii extending well beyond an effective radius, or large

M. R. Bate, I. A. Bonnell, N. M. Price

A method for following fragmentation simulations further in time using smoothed particle hydrodynamics (SPH) is presented. In a normal SPH simulation of the collapse and fragmentation of a molecular cloud, high-density regions of gas that form protostars are represented by many particles with small separations. These high-density regions require small time s

Mario Vietri

I consider the possibility that Ultra High Energy Cosmic Rays are accelerated in Gamma Ray Bursts located in the Galactic corona, thus circumventing the problem raised by Greisen--Zatsepin--Kuz&#39;min cutoff. The acceleration of UHECRs could occur in the pulsars which, in the coronal GRB model, produce them: the same parameters that permit fitting GRBs&#39;

K. Heinemann, G. Ripken, F. Schmidt

The aim of this paper is to construct six-dimensional symplectic thin-lens transport maps for the tracking program SIXTRACK, continuing an earlier report by using another method which consistes in applying Lie series and exponentiation as described by W. Groebner and for canonical systems by A.J. Dragt. We firstly use an approximate Hamiltonian obtained by a

Petr Horava, Edward Witten

We propose that the ten-dimensional $E_8\times E_8$ heterotic string is related to an eleven-dimensional theory on the orbifold ${\bf R}^{10}\times {\bf S}^1/{\bf Z}_2$ in the same way that the Type IIA string in ten dimensions is related to ${\bf R}^{10}\times {\bf S}^1$. This in particular determines the strong coupling behavior of the ten-dimensional $E_8

I. Ya. Aref&#39;eva, I. V. Volovich

The master fields for the large $N$ limit of matrix models and gauge theory are constructed. The master fields satisfy to standard equations of relativistic field theory but fields are quantized according to a new rule. To define the master field we use the Yang-Feldman equation with a free field quantized in the Boltzmannian Fock space. The master field for

Wolfgang Bock, Julius Kuti

The renormalized trajectory in the multi-dimensional coupling parameter space of the two-dimensional O(3) non-linear sigma model is determined numerically under \linebreak $δ$-function block spin transformations using two different Monte Carlo renormalization group techniques. The renormalized trajectory is compared with the straight line of the fixed point

L. Ya. Glozman

New results on baryon structure and spectrum developed in collaboration with Dan Riska [1-4] are reported. The main idea is that beyond the chiral symmetry spontaneous breaking scale light and strange baryons should be considered as systems of three constituent quarks with an effective confining interaction and a chiral interaction that is mediated by the oc

Sean M. Carroll, Miguel E. Ortiz, Washington Taylor

We use the method of discrete loop equations to calculate exact correlation functions of spin and disorder operators on the sphere and on the boundary of a disk in the $c = 1/2$ string, both in the Ising and dual Ising matrix model formulations. For both the Ising and dual Ising theories the results on the sphere are in agreement with the KPZ/DDK scaling pre

G. Krein, D. P. Menezes, M. B. Pinto

The optimized $δ$-expansion is used to study vacuum polarization effects in the Walecka model. The optimized $δ$-expansion is a nonperturbative approach for field theoretic models which combines the techniques of perturbation theory and the variational principle. Vacuum effects on self-energies and the energy density of nuclear matter are studied up to ${\ca

G. A. Lalazissis, M. M. Sharma, P. Ring

A systematic study of the ground-state properties of even-even rare earth nuclei has been performed in the framework of the Relativistic Mean-Field (RMF) theory using the parameter set NL-SH. Nuclear radii, isotope shifts and deformation properties of the heavier rare-earth nuclei have been obtained, which encompass atomic numbers ranging from Z=60 to Z=70 a

H. Y. Huang, F. Y. Wu, H. Kunz, D. Kim

The problem of close-packed dimers on the honeycomb lattice was solved by Kasteleyn in 1963. Here we extend the solution to include interactions between neighboring dimers in two spatial lattice directions. The solution is obtained by using the method of Bethe ansatz and by converting the dimer problem into a five-vertex problem. The complete phase diagram i

Kazuhiro Sano, Ken&#39;ichi Takano

We examined a two-dimensional Heisenberg model with two kinds of exchange energies, $J_e$ and $J_c$. This model describes localized spins at vanadium ions in a layer of CaV$_4$O$_9$, for which a spin gap is found by a recent experiment. Comparing the high temperature expansion of the magnetic susceptibility to experimental data, we determined the exchange en

Stephan Rosebrock, Gunter Huck

We present four generalized small cancellation conditions for finite presentations and solve the word- and conjugacy problem in each case. Our conditions $W$ and $W^*$ contain the non-metric small cancellation cases C(6), C(4)T(4), C(3)T(6) (see [LS]) but are considerably more general. $W$ also contains as a special case the small cancellation condition $W(6

Andrew Strominger

This is a non-technical version of a talk presented at the conference, &#34;S-Duality and Mirror Symmetry in String Theory&#34; Trieste, June, 1996 which will appear in the proceedings.

Ivan G. Avramidi, Rainer Schimming

We present a brief overview of several approaches for calculating the local asymptotic expansion of the heat kernel for Laplace-type operators. The different methods developed in the papers of both authors some time ago are described in more detail.

K. Agashe, M. Graesser

We show that supersymmetric $R$-parity breaking ($\not R_p$) interactions always result in Flavor Changing Neutral Current (FCNC) processes. Within a single coupling scheme, these processes can be avoided in either the charge $+2/3$ or the charge $-1/3$ quark sector, but not both. These processes are used to place constraints on \Rp couplings. The constraint

S. V. Panyukov, A. D. Zaikin

It is shown that practically any physically relevant random distribution of offset charges destroys the Kosterlitz-Thouless-Berezinskii charge-unbinding phase transition in two dimensional normal and superconducting granular arrays and films. The array conductance obeys the Arrenius dependence on temperature. Offset charge disorder decreases the effective Co

Michael E. Bleich, Joshua E. S. Socolar

Extended time-delay auto-synchronization (ETDAS) is a promising technique for stabilizing unstable periodic orbits in low-dimensional dynamical systems. The technique involves continuous feedback of signals delayed by multiples of the orbit&#39;s period in a manner that is especially well-suited for fast systems and optical implementation. We show how to ana

E. Martinec

The effective action of N=2 Yang-Mills theory with adjoint matter is shown to be governed by an integrable spin model with spectral parameter on an elliptic curve. We sketch a route to deriving this effective dynamics from the underlying Yang-Mills theory. Natural generalizations of this structure to all N=2 models, and to string theory, are suggested.

M. Farhoudi

We show that the splitting feature of the Einstein tensor, as the first term of the Lovelock tensor, into two parts, namely the Ricci tensor and the term proportional to the curvature scalar, with the trace relation between them is a common feature of any other homogeneous terms in the Lovelock tensor. Motivated by the principle of general invariance, we fin

P. T. de Zeeuw

Luminous galaxies and their dark halos are likely to have triaxial shapes. The construction of distribution functions for triaxial systems is a hard problem, due to the existence of only one exact integral of motion, the energy $E$. Even so, progress has been made by use of analytic methods for special potentials, numerical combination of orbit densities (Sc

Hsiu-Hau Lin, Matthew P. A. Fisher

We study the effect of an ac drive on the current-voltage (I-V) characteristics of a tunnel junction between two fractional Quantum Hall fluids at filling $ν^{-1}$ an odd integer. Within the chiral Luttinger liquid model of edge states, the point contact dynamics is described by a driven damped quantum mechanical pendulum. In a semi-classical limit which ign

Kyungsik Kang, Sung Ku Kim

We present the results of fitting all data for $pp$ and $\bar pp$ scattering at $\sqrt s \geq 9.7$ Gev and up to the collider energy with various analytic parametrizations of the elastic forward scattering amplitudes based on the derivative dispersion relation. It is found that the model containing the Pomeron and Reggeon terms with 8 parameters has the most

Ruth Gregory

We consider the metrics for cosmic strings and $p$-branes in spacetime dimension $N>4$, that is, we look for solutions to Einstein-Maxwell-Dilaton gravity in $N$-dimensions with boost symmetry in the $p$-directions along the brane. Focussing first in detail on the five dimensional uncharged cosmic string we discuss the solution, which turns out to have a nak

Anindya Datta, Amitava Raychaudhuri, Sreerup Raychaudhuri, Surajit Chakrabarti

Many extensions of the Standard Model include $SU(2)_L \times U(1)_Y$ singlet higgs bosons, $h^0$, and also vectorlike fermions which couple to it. The production and detection possibilities of such singlet neutral scalars at hadron colliders are considered for different scenarios of vectorlike fermions. We find that for some values of masses and couplings,

Igor Batalin, Robert Marnelius

The general structure of the Sp(2) covariant version of the field-antifield quantization of general constrained systems in the Lagrangian formalism, the so called triplectic quantization, as presented in our previous paper with A.M.Semikhatov is further generalized and clarified. We present new unified expressions for the generating operators which are more

Helmut Hofmann, Fedor A. Ivanyuk, Shuhei Yamaji

We study slow collective motion of isoscalar type at finite excitation. The collective variable is parameterized as a shape degree of freedom and the mean field is approximated by a deformed shell model potential. We concentrate on situations of slow motion, as guaranteed, for instance, by the presence of a strong friction force, which allows us to apply lin

Wei-Min Zhang

In this paper, we develop a weak-coupling treatment of nonperturbative QCD to heavy hadrons on the light-front. First, we present a derivation of quark confining interaction in light-front QCD for heavy quark systems, based on the recently developed light-front similarity renormalization group approach and the light-front heavy quark effective theory. The re

Nobuhiro Maekawa, Tomohiko Takahashi

Recently one of the authors proposed a dual theory of a Supersymmetric Standard Model (SSM), in which it is naturally understood that at least one quark (the top quark) should be heavy, i.e., almost the same order as the weak scale, and the supersymmetric Higgs mass parameter $μ$ can naturally be expected to be small. However, the model cannot have Yukawa co

H. B. O&#39;Connell, A. G. Williams, M. Bracco, G. Krein

We discuss the consistency of the traditional vector meson dominance (VMD) model for photons coupling to matter, with the vanishing of vector meson-meson and meson-photon mixing self-energies at q^2=0. This vanishing of vector mixing has been demonstrated in the context of rho-omega mixing for a large class of effective theories. As a further constraint on s

I. R. Klebanov, L. Thorlacius

We obtain form factors for scattering of gravitons and anti-symmetric tensor particles off Dirichlet $p$-branes in Type II superstring theory. As expected, the form factor of the -1-brane (the D-instanton) exhibits point-like behavior: in fact it is saturated by a single dilaton tadpole graph. In contrast, $p$-branes with $p>-1$ acquire size of order the str

Andrew E. Chubykalo

A study of kinematics of a 2-body system is used to show that the Mach principle, previously rejected by general relativity, can still serve as an alternative to the concept of absolute space, if one takes into account that the background of distant stars (galaxies) determines {\it both} the inertial and the gravitational masses of a body.

Bogdan A. Dobrescu

We present a new mechanism for gluino mass generation in models of dynamical supersymmetry breaking. The mechanism requires two colored chiral superfields which feel a nonabelian gauge interaction such that a fermion condensate is formed at a scale of order 1 TeV. Renormalizable hidden sector models, which typically yield unacceptably light gauginos, become

P. Calvani, M. Capizzi, S. Lupi, P. Maselli

Polaronic features similar to those previously observed in the photoinduced spectra of cuprates have been detected in the reflectivity spectra of chemically doped parent compounds of high-critical-temperature superconductors, both $n$-type and $p$-type. In Nd$_2$CuO$_{4-y}$ these features, whose intensities depend both on doping and temperature, include loca

Robert Bluhm, Alan Kostelecky, James Porter

Localized quantum wave packets can be produced in a variety of physical systems and are the subject of much current research in atomic, molecular, chemical, and condensed-matter physics. They are particularly well suited for studying the classical limit of a quantum-mechanical system. The motion of a localized quantum wave packet initially follows the corres

F. X. Lee, L. E. Wright, C. Bennhold

We present calculations of the reaction $A(e,e^\prime πN)B$ in the distorted wave impulse approximation. The reaction allows for the study of the production process in the nuclear medium without being obscured by the details of nuclear transition densities. First, a pion electroproduction operator suitable for nuclear calculations is obtained by extending th

H. Sorge

The hadronic phase space distributions calculated with the transport model RQMD for central S(200 AGeV) on S and Pb(160AGeV) on Pb collisions are analyzed to study the deviations from ideal hydrodynamical evolution. After the preequilibrium stage, which lasts for approximately 4 (2) fm/c in Pb+Pb (S+S) the source stays in approximate kinetic equilibrium for

R. Rapp, J. Wambach

Within the finite-temperature Greens-function formalism we study the equation of state of a hot interacting pion gas at zero chemical potential. Employing realistic $ππ$ meson-exchange interactions we selfconsistently calculate the in-medium single-pion selfenergy and the $ππ$ scattering amplitude in the quasiparticle approximation. These quantities are then

Stanislaw J. Szarek, D. Voiculescu

In noncommutative probability theory independence can be based on free products instead of tensor products. This yields a highly noncommutative theory: free probability . Here we show that the classical Shannon&#39;s entropy power inequality has a counterpart for the free analogue of entropy . The free entropy (introduced recently by the second named author)

A. G. Mirzabekian, G. A. Vilkovisky, V. V. Zhytnikov

The vacuum action for the gravitational field admits a known expansion in powers of the Ricci tensor with nonlocal operator coefficients (form factors). We show that going over to a different basis of curvature invariants makes possible a partial summation of this expansion. Only the form factors of the Weyl-tensor invariants need be calculated. The full act

M. Beneke, V. A. Smirnov

We analyze the large-order behaviour in perturbation theory of classes of diagrams with an arbitrary number of chains (i.e. photon lines, dressed by vacuum polarization insertions). We derive explicit formulae for the leading and subleading divergence as $n\to\infty$, and a complete result for the vacuum polarization at the next-to-leading order in $1/N_f$.

A. Bashir, M. R. Pennington

We discuss the structure of the non-perturbative fermion-boson vertex in quenched QED. We show that it is possible to construct a vertex which not only ensures that the fermion propagator is multiplicatively renormalizable, obeys the appropriate Ward-Takahashi identity, reproduces perturbation theory for weak couplings and guarantees that the critical coupli

A. Bernicha, G. Lopez Castro, J. Pestieau

Based on the S-matrix approach, we introduce a modified formula for the $π^{\pm}$ electromagnetic form factor which describes very well the experimental data in the energy region $2m_π \leq \sqrt{s} \leq 1.1$ GeV. Using the CVC hypothesis we predict $B(\tpp) = (24.75 \pm 0.38)\% $, in excellent agreement with recent experiments.

M. Goodband, M. Hindmarsh

We examine the Standard Model field configurations near cosmic strings in a particular class of models. This class is defined by the condition that the generator of the flux in the string, $T_s$, commutes with the Standard Model Lie algebra. We find that if the Standard Model Higgs carries a charge $F_h /2$ under $T_s$, cosmic string solutions have Z-flux $Φ

C. Boros

It is pointed out that the recently measured left-right asymmetries in inclusive pion and lambda hyperon production processes are in very good agreement with the relativistic quark model, proposed some time ago. Further predictions based on this model for hyperon productions, for lepton pair productions and for W/Z-boson productions are also presented.

R. Casalbuoni, A. Deandrea, S. De Curtis, D. Dominici

We discuss possible symmetries of effective theories describing spinless and spin 1 bosons, mainly to concentrate on an intriguing phenomenological possibility: that of a hardly noticeable strong electroweak sector at relatively low energies. Specifically, a model with both vector and axial vector strong interacting bosons may possess a discrete symmetry imp

G. Mangano, G. Miele, G. Migliore

The phenomenological evidence of quantum statistical effects in parton physics is here briefly summarized, and the recent good results obtained by parameterizing the parton distributions in terms of Fermi-Dirac and Bose-Einstein statistical functions are discussed. In this framework we study the modification of the scaling behaviour of parton distributions d

W. Vogelsang

A next-to-leading order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton nucleon scattering is presented within the framework of the radiative parton model. The $Q^2$-dependence of the spin asymmetry $A_1^{p}(x,Q^2)$ is shown to be non-negligible for $x$-values relevant for the analysis of the present data. In the s

A. Yu. Ignatiev, G. C. Joshi

We investigate in detail the problem of constructing magnetic monopole solutions within the finite-range electrodynamics (i.e., electrodynamics with non-zero photon mass, which is the simplest extension of the standard theory; it is fully compatible with the experiment). We first analyze the classical electrodynamics with the additional terms describing the

Gerard Barkema, John McCabe

The critical properties of the 2D Ising and 3-state Potts models are investigated using Monte Carlo simulations. Special interest is given to measurement of 3-point correlation functions and associated universal objects, i.e. structure constants. The results agree well with predictions coming from conformal field theory confirming, for these examples, the co

Sergey S. Kokarev

Full generalization of Kasner metric for the case of $n+1$ dimensions and $m\le n+1$ essential variables is obtained. Any solution is defined by the corresponding constant matrix of Kasner parameters. This parameters form in euclidian space Casner hyperspheres and are connected by additional conditions. General properties of obtained solutions are analyzed.

Bruce Allen, Bernard S. Kay, Adrian C. Ottewill

We combine and further develop ideas and techniques of Allen \& Ottewill, Phys. Rev.D, {\bf 42}, 2669 (1990) and Kay \& Studer Commun. Math. Phys., {\bf 139}, 103 (1991) for calculating the long range effects of cosmic string cores on classical and quantum field quantities far from an (infinitely long, straight) cosmic string. We find analytical approximatio

Biplab Bhawal

We describe how exactly the intra-cavity fields in a dual recycling cavity build up their power before achieving a steady state value. We restricted our analysis here to interferometers with lossless mirrors and beam-splitter. The complete series representation of the intra-cavity lights at any stage of evolution in non-steady state have been presented.

R. Brunetti, K. Fredenhagen, M. Koehler

Quantum fields propagating on a curved spacetime are investigated in terms of microlocal analysis. We discuss a condition on the wave front set for the corresponding n-point distributions, called ``microlocal spectrum condition&#39;&#39; ($μ$SC). On Minkowski space, this condition is satisfied as a consequence of the usual spectrum condition. Based on Radzik

T. P. Pareek, A. M. Jayannavar

We have analysed the nature of persistent currents in open coupled mesoscopic rings. Our system is comprised of two ideal loops connected to an electron reservoir. We have obtained analytical expressions for the persistent current densities in two rings in the presence of a magnetic field. We show that the known even-odd parity effects in isolated single loo

V. G. Kantser, N. M. Malkova

The stressed heterojunctions with antiferromagnetic ordering in which the constituents have oppposite band edge symmetry and their gaps have opposite signs have been investigated. The interface states have been shown to appear in these heterojunctions and they are spin-split. As a result if the Fermi level gets into one of the interface bands then it leads t

B. D. Rajput, D. A. Browne

We extend the adiabatic bond charge model, originally developed for group IV semiconductors and III-V compounds, to study phonons in more ionic II-VI compounds with a zincblende structure. Phonon spectra, density of states and specific heats are calculated for six II-VI compounds and compared with both experimental data and the results of other models. We sh

Amartya Bhattacharjya, Shoudan Liang

Kauffman net is a dynamical system of logical variables receiving two random inputs and each randomly assigned a boolean function. We show that the attractor and transient lengths exhibit scaleless behavior with power-law distributions over up to ten orders of magnitude. Our results provide evidence for the existence of the &#34;edge of chaos&#34; as a disti

W. Belzig, C. Bruder, Gerd Schön

The magnetic response of a proximity-coupled superconductor-normal metal sandwich is studied within the framework of the quasiclassical theory. The magnetization is evaluated for finite values of the applied magnetic field (linear and nonlinear response) at arbitrary temperatures and is used to fit recent experimental low-temperature data. The hysteretic beh

M. T. Batchelor, Y. K. Zhou

We give a physical interpretation of the entries of the reflection $K$-matrices of Baxter&#39;s eight-vertex model in terms of an Ising interaction at an open boundary. Although the model still defies an exact solution we nevertheless obtain the exact surface free energy from a crossing-unitarity relation. The singular part of the surface energy is described

Jakub Zakrzewski, Robert Gebarowski, Dominique Delande

The ionization of hydrogen Rydberg atoms by circularly polarized microwaves is studied quantum mechanically in a model two dimensional atom. We apply a combination of a transformation to the coordinate frame rotating with the field, with complex rotation approach and representation of atomic subspace in Sturmian-type basis. The diagonalization of resulting m

P. Poggi, S. Ruffo

After a brief comprehensive review of old and new results on the well known Fermi-Pasta-Ulam (FPU) conservative system of $N$ nonlinearly coupled oscillators, we present a compact linear mode representation of the Hamiltonian of the FPU system with quartic nonlinearity and periodic boundary conditions, with explicitly computed mode coupling coefficients. The

S. D. Landy, S. A. Shectman, H. Lin, R. P. Kirshner

We have measured the 2 dimensional (2D) power spectrum of the Las Campanas Redshift Survey on scales between 30 and 200 Mpc (q_0=0.5, H_o=100h km sec^{-1} Mpc^{-1}). Such an analysis is more sensitive to structure on scales > 50 Mpc than a full 3 dimensional analysis given the geometry of the survey. We find a strong peak in the power spectrum at approximate

E. M. Gouveia Dal Pino, A. H. Cerqueira

We present fully three-dimensional hydrodynamical and magnetohydrodynamical simulations of supersonic, radiative cooling jets propagating into homogeneous and stratified environments based on Smoothed Particle Hydrodynamics technique.

F. P. Pijpers, M. J. Thompson

We present an efficient method for two dimensional inversions for the solar rotation rate using the Subtractive Optimally Localized Averages (SOLA) method and a modification of the R1 X R1 technique proposed by Sekii (1993). The SOLA method is based on explicit construction of averaging kernels similar to the Backus-Gilbert method. The versatility and reliab

V. Sahni, S. F. Shandarin

We study the behaviour of spherical Voids in Lagrangian perturbation theories L(n), of which the Zel&#39;dovich approximation is the lowest order solution L(1). We find that at early times higher order L(n) give an increasingly accurate picture of Void expansion. However at late times particle trajectories in L(2) begin to turnaround and converge leading to

R. Fedele, G. Miele, L. Palumbo

On the basis of the recently proposed {\it Thermal Wave Model (TWM) for particle beams}, we give a description of the longitudinal charge particle dynamics in circular accelerating machines by taking into account both radiation damping and quantum excitation (stochastic effect), in presence of a RF potential well. The longitudinal dynamics is governed by a 1

R. Fedele, F. Galluccio, V. I. Man&#39;ko, G. Miele

Within the Thermal Wave Model framework a comparison among Wigner function, Husimi function, and the phase-space distribution given by a particle tracking code is made for a particle beam travelling through a linear lens with small aberrations. The results show that the quantum-like approach seems to be very promising.

Matthias Blau, Faheem Hussain, George Thompson

We investigate in detail the topological gauged Wess-Zumino-Witten models describing topological Kazama-Suzuki models based on complex Grassmannians. We show that there is a topological sector in which the ring of observables (constructed from the Grassmann odd scalars of the theory) coincides with the classical cohomology ring of the Grassmannian for all va

Sean M. Carroll, Miguel E. Ortiz, Washington Taylor

We present a self-contained analysis of theories of discrete 2D gravity coupled to matter, using geometric methods to derive equations for generating functions in terms of free (noncommuting) variables. For the class of discrete gravity theories which correspond to matrix models, our method is a generalization of the technique of Schwinger-Dyson equations an

David B. Kaplan, Martin Schmaltz

We extend work by Callan and Harvey and show how the phase of the chiral fermion determinant in four dimensions is reproduced by zeromodes bound to a domain wall in five dimensions. The analysis could shed light on the applicability of zeromode fermions and the vacuum overlap formulation of Narayanan and Neuberger for chiral gauge theories on the lattice.

J. Vandegriff, G. Raimann, R. N. Boyd, M. Caffee

A search for stable strange quark nuggets has been conducted in helium and argon using a high sensitivity mass spectrometer. The search was guided by a mass formula for strange quark nuggets which suggested that stable strange helium might exist at a mass around 65 u. The chemical similarity of such ``strangelets'' to noble gas atoms and the gravitational un

Serge Winitzki, Alexander Vilenkin

In a previous paper \cite{MakingPredictions}, a method of comparing the volumes of thermalized regions in eternally inflating universe was introduced. In this paper, we investigate the dependence of the results obtained through that method on the choice of the time variable and factor ordering in the diffusion equation that describes the evolution of eternal

Hsiang-nan Li

We show that the resummation technique developed recently for heavy-light systems and the conventional approach based on the factorization of Wilson loops are equivalent. The two methods lead to the same results of the resummation of large corrections in inclusive $B$ meson decays.

Friedemann Brandt, Walter Troost, Antoine Van Proeyen

We construct and discuss all background charges and continuous consistent deformations of standard $2d$ gravity theories with scalar matter fields. It turns out that the background charges and those deformations which change nontrivially both the form of the action and of its gauge symmetries are closely linked and exist only if the target space has at least

The ZEUS Collaboration

Photoproduction events which have two or more jets have been studied in the $W_{γp}$ range 135~GeV $< W_{γp} <$ 280~GeV with the ZEUS detector at HERA. A class of events is observed with little hadronic activity between the jets. The jets are separated by pseudorapidity intervals ($Δη$) of up to four units and have transverse energies greater than 6~GeV. A g

M. C. Gonzalez-Garcia

Our goal in this paper is to examine the discovery potential of laboratory experiments searching for the oscillation $ν_μ(ν_e) \rightarrow ν_τ$, in the light of recent data on solar and atmospheric neutrino experiments, which we analyse together with the most restrictive results from laboratory experiments on neutrino oscillations in a four-neutrino framewor

Arturo Serna, Jean-Michel Alimi

We present a detailed calculation of the light element production in the framework of Scalar-Tensor (ST) theories of gravitation. The coupling function ωhas been described by an appropriate form which reproduces all the possible asymptotic behaviors at early times of viable ST cosmological models with a monotonic ω(Φ). This form gives an exact representation

Arturo Serna, Jean-Michel Alimi

We analyze the qualitative behaviors of scalar-tensor cosmologies with an arbitrary monotonic $ω(Φ)$ function. In particular, we are interested on scalar-tensor theories distinguishable at early epochs from General Relativity (GR) but leading to predictions compatible with solar-system experiments. After extending the method developed by Lorentz-Petzold and

Howard E. Haber

An introduction to the minimal supersymmetric Standard Model (MSSM) is given. The motivation for ``low-energy&#39;&#39; supersymmetry is reviewed, and the structure of the MSSM is outlined. In its most general form, the MSSM can be viewed as a low-energy effective theory parametrized by a set of arbitrary soft-supersymmetry-breaking parameters. A variety of

A. S. Belyaev, E. E. Boos

The possibility of single and pair excited neutrino production in high energy e+e-, gamma-e and gamma-gamma collisions on linear colliders is studied. The integrated cross sections of these subproceses are calculated. Special attention is paid to search for excited neutrino in e-gamma --> W- W+ e process. Lower limits for the compositeness parameter estimate

Lajos Diosi

Starting from the Schrödinger-equation of a composite system, we derive unified dynamics of a classical harmonic system coupled to an arbitrary quantized system. The classical subsystem is described by random phase-space coordinates entangled with the quantized variables of the complementary subsystem. Our semiclassical equation is {\it true} in a sense that

K. Berndl, D. Duerr, S. Goldstein, N. Zanghi

We discuss the problem of finding a Lorentz invariant extension of Bohmian mechanics. Due to the nonlocality of the theory there is (for systems of more than one particle) no obvious way to achieve such an extension. We present a model invariant under a certain limit of Lorentz transformations, a limit retaining the characteristic feature of relativity, the

Stefan V. Mashkevich, Vladimir S. Mashkevich

Quantum decoherence is of primary importance for relaxation to an equilibrium distribution and, accordingly, for equilibrium processes. We demonstrate how coherence breaking implies evolution to a microcanonical distribution (``microcanonical postulate&#39;&#39;) and, on that ground, consider an adiabatic process, in which there is no thermostat. We stress i

D. G. Pak

A variety of three-dimensional left-covariant differential calculi on the quantum group $SU_q(2)$ is considered using an approach based on global $ U(1) $ -covariance. Explicit representations of possible $q $-Lie algebras are constructed in terms of differential operators. A gauge covariant differential algebra is uniquely determined. The non-standard Leibn

Laurent Daudet, Valerie Ego, Sebastien Manneville, John Bechhoefer

Secondary instabilities of Faraday waves show three regimes: (1) As seen previously, low-viscosity (nu) fluids destabilize first into squares. At higher driving accelerations a, squares show low-frequency modulations corresponding to the motion of phase defects, while theory predicts a stationary transverse amplitude modulation (TAM). (2) High-nu fluids dest

S. A. Kulagin, W. Melnitchouk, T. Weigl, W. Weise

We present a model description of the nucleon valence structure function applicable over the entire region of the Bjorken variable x, and above moderate values of Q**2 (> 1 GeV**2). We stress the importance of describing the complete spectrum of intermediate states which are spectator to the deep-inelastic collision. At a scale of 1 GeV**2 the relevant degre

Topi Kärki, Antti J. Niemi

We study the partition function of N=1 supersymmetric De Rham quantum mechanics on a Riemannian manifold, with a nontrivial chemical potential $μ$ for the fermions. General arguments suggest that when $μ\to \infty$ we should get the partition function of a free point particle. We investigate this limit by exact evaluation of the fermionic path integral. In e

B. M. Pimentel, A. T. Suzuki, J. L. Tomazelli

Applying the principle of analytic extension for generalized functions we derive causal propagators for algebraic non-covariant gauges. The so generated manifestly causal gluon propagator in the light-cone gauge is used to evaluate two one-loop Feynman integrals which appear in the computation of the three-gluon vertex correction. The result is in agreement

Bertfried Fauser, Harald Stumpf

The functional quantum field theory, developed by Stumpf, provides the possibility to derive the quantum dynamics of a positronium gas from Coulomb interacting electrons and positrons. By this example, the method will be brought in a Clifford algebraic light, through identifying the functional space with an infinite dimensional Euclidean Clifford algebra.

W. M. Kloet, F. Myhrer

A simple partial wave amplitude analysis of $\overline{p}p \rightarrow π^- π^+$ has been performed for data in the range p$_{\sl lab}$ = 360 -- 1000 MeV/c. Remarkably few partial waves are required to fit the data, while the number of required $J$ values barely changes over this energy range. However, the resulting set of partial wave amplitudes is not uniqu

Zhen Cao, Rudolph C. Hwa

The notion of chaotic behavior is examined for particle production in branching processes. Two types of branching are considered: non-Abelian gauge interaction and an Abelian cascade model. Properties of the production processes are investigated by Monte Carlo stimulation. The ``temporal&#39;&#39; behavior is studied by following the fluctuations in the mult

Chi-Keung Chow

It is shown that, in the bound state picture, the $Λ_c(2593) \toΛ_cγ$ and $Λ_c(2625)\toΛ_cγ$ decays are severely suppressed. On the other hand, for their bottom counterparts, which are predicted to have masses 5900 and 5926 MeV respectively, may have significant radiative branching ratio. In particular, the $Λ_b(5926)\toΛ_bγ$ mode may even dominate over the

E. W. N. Glover, David A. Kosower

A jet algorithm must specify how to (re-)combine different partons or towers into a single four-vector. Various recombination schemes have been used experimentally to examine the transverse energy profile of jets in hadron colliders. Generally, the data is insensitive to which scheme is used. However, we argue that the recombination scheme previously used by

Lech Mankiewicz, Eckart Stein, Andreas Schäfer

We discuss various estimates of the magnitude of higher-twist corrections to the Bjorken sum rule in polarized deep inelastic scattering.

Jörn Knoll, Dmitri N. Voskresensky

Some considerations about the importance of coherence effects for bremsstrahlung processes in non--equilibrium dense matter (Landau - Pomeranchuk - Migdal - effect) are presented. They are of particular relevance for the application to photon - and di-lepton production from high energy nuclear collisions, to gluon radiation in QCD transport, or parton kineti