October 1996 arXiv papers — page 3

B. Kaulakys

A consistent analytical approach for calculation of the quasiclassical radial dipole matrix elements in the momentum and coordinate representations is presented. Very simple but relatively precise expressions for the matrix elements are derived in both representations. All analytical expressions contain only one special function -- the Anger function and its

Attila Csoto

I show that off-shell effects, like antisymmetrization and Be-7 distortions, can significantly influence the energy dependence of the nonresonant Be7(p,gamma)B8 astrophysical S factor at higher energies. The proper treatment of these effects results in a vitrually flat E1 component of the S factor at E_cm = 0.3-1.5 MeV energies in the present eight-body mode

Urs Achim Wiedemann, Ulrich Heinz

In heavy ion collisions resonances can create strong non-Gaussian effects in the 2-pion correlation data. Hence, the commonly used Gaussian fit parameters do not fully characterize these correlators. We suggest a different set of HBT parameters which does not presuppose a particular shape of the correlator and allows to extract additional (non-Gaussian) info

L. A. Winckelmann, C. Ernst, L. Gerland, J. Konopka

The behavior of hadronic matter at high baryon densities is studied within Ultrarelativistic Quantum Molecular Dynamics (URQMD). Baryonic stopping is observed for Au+Au collisions from SIS up to SPS energies. The excitation function of flow shows strong sensitivities to the underlying equation of state (EOS), allowing for systematic studies of the EOS. Dilep

Nathan Berkovits

Superstring field theory was recently used to derive a four-dimensional Maxwell action with manifest duality. This action is related to the McClain-Wu-Yu Hamiltonian and can be locally coupled to electric and magnetic sources. In this letter, the manifestly dual Maxwell action is supersymmetrized using N=1 and N=2 superspace. The N=2 version may be useful fo

Shailesh Chandrasekharan

We construct a model of a chiral transition using the well known large N transition in two dimensional U(N) lattice gauge theory. Restricting the model to a single plaquette, we introduce Grassmann variables on the corners of the plaquette with the natural phase factors of staggered fermions and couple them to the U(N) link variables. The classical theory ha

I. P. Ennes, A. V. Ramallo, J. M. Sanchez de Santos

We study the free field realization of the two-dimensional osp(1|2) current algebra. We consider the case in which the level of the affine osp(1|2) symmetry is a positive integer. Using the Coulomb gas technique we obtain integral representations for the conformal blocks of the model. In particular, from the behaviour of the four-point function, we extract t

O. Kechkin, M. Yurova

A class of the $D=4$ gravity models describing a coupled system of $n$ Abelian vector fields and the symmetric $n \times n$ matrix generalizations of the dilaton and Kalb-Ramond fields is considered. It is shown that the Pecci-Quinn axion matrix can be entered and the resulting equations of motion possess the $Sp(2n, R)$ symmetry in four dimensions. The stat

Luis Alvarez-Consul, C. P. Martin

We compute the dependence on the classical action "gauge" parameters of the beta functions of the standard topological sigma model in flat space. We thus show that their value is a "gauge" artifact indeed. We also show that previously computed values of these beta functions can be continuously connected to one another by smoothly varying thos

P. Mathieu

At $c=3$, two of the three integrable quantum $N=2$ supersymmetric Korteweg-de Vries equations become identical (SKdV$_1$ and SKdV$_4$). Quite remarkably, all their conservation laws can be written in closed form, which provides thus a simple constructive integrability proof.

Robert Carroll

Further formulas are presented involving quantum mechanics, thermodynamics, and integrable systems. Modifications of dispersionless theory are developed.

G. C. Nayak, V. Ravishankar

We study the production and the equilibration of a non-Abelian $q\bar{q}$ plasma in an external chromoelectric field, by solving the Boltzmann equation with the non-Abelian features explicitly incorporated. We consider the gauge group $SU(2)$ and show that the colour degree of freedom has a major and dominant role in the dynamics of the system. It is seen th

V. E. Markushin

Two-step mechanisms in the $N\bar{N}$ annihilation and their role in the OZI rule violating reactions are discussed. In particular the two meson rescattering mechanism for $πϕ$ channel including all off-shell effects is typically two orders of magnitude bigger than the OZI tree level expectation and explains the observed ratio $ϕπ/ωπ$ in the annihilation at

K. Langfeld, H. Reinhardt, M. Quandt

Yang-Mills theory is studied in a variant of 't Hooft's maximal Abelian gauge. In this gauge magnetic monopoles arise in the Abelian magnetic field. We show, however, that the full (non-Abelian) magnetic field does not possess any monopoles, but rather strings of magnetic fluxes. We argue that these strings are the relevant infrared degrees of freedo

Satoshi Matsuda

The parameter space of the Feigin-Fuks representations of the N=4 SU(2)$_k$ superconformal algebras is studied from the viewpoint of the specral flow. The $η$ phase of the spectral flow is nicely incorporated through twisted fermions and the spectral flow resulting from the inner automorphism of the N=4 superconformal algebras is explicitly shown to be opera

Yuhsuke Yoshida

Instanton calculations are demonstrated from a viewpoint of twisted topological field theory. Various properties become manifest such that perturbative corrections are terminated at one-loop, and norm cancellations occur between bosonic and fermionic excitations in any instanton background. We can easily observe that for a suitable choice of Green functions

S. P. Brumby, B. E. Hanlon, G. C. Joshi

Taking the complex nature of quantum mechanics which we observe today as a low energy effect of a broken quaternionic theory we explore the possibility that dark matter arises as a consequence of this underlying quaternionic structure to our universe. We introduce a low energy, effective, Lagrangian which incorporates the remnants of a local quaternionic alg

Kazuya Yuasa, Hiromichi Nakazato

The quantum mechanical transition amplitudes are calculated perturbatively on the basis of the stochastic quantization method of Parisi and Wu. It is shown that the stochastic scheme reproduces the ordinary result for the amplitude and systematically incorporates higher-order effects, even at the lowest order.

J. D. Bjorken

New directions for exploring QCD at future high-energy colliders are sketched. These include jets within jets, BFKL dynamics, soft and hard diffraction, searches for disoriented chiral condensate, and doing a better job on minimum bias physics. The new experimental opportunities include electron-ion collisions at HERA, a new collider detector at the C0 regio

S. Riemann

The discovery of a Z' and the measurement of Z' couplings to fermions are main tasks of future colliders. Here, the possibilities to measure Z' f \bar f couplings at an NLC operating below a Z' resonance are studied. In dependence on the mass of the Z' and the collider parameters one will be able to discriminate between Z' models.

Guido Müller

We perform the complete regularization of all Green functions with a single incoming and outgoing baryon to order q^3 in the low energy expansion for the SU(3) meson-baryon system in chiral perturbation theory. The divergences can be extracted in a chiral invariant manner by making use of the heat kernel representation of the propagators in d-dimensional Euc

Andrei I. Davydychev

A brief overview of some recent publications related to the evaluation of two-loop Feynman diagrams is given. (Talk given at the International Symposium on Radiative Corrections CRAD96, Cracow, Poland, 1--5 August 1996)

A. A. Pankov, N. Paver

We discuss the potential of NLC500 and NLC1000 to probe Z-Z' mixing and mass by the reaction e^+e^- -> W^+W^- with longitudinally polarized electrons. We perform a model-independent analysis of the deviations from the Standard Model, and apply it to a specific class of extended weak gauge models. Results indicate that the corresponding bounds at the NLC5

J. Blümlein, E. Boos, A. Kryukov

The cross section for vector leptoquark pair production in $e^+e^-$ annihilation is calculated for the case of finite anomalous gauge boson couplings $κ_{γ, Z}$ and $λ_{γ, Z}$. The minimal cross section is found to behave $\propto β^7$, leading to weaker mass bounds in the threshold range than in models studied previously.

K. Sridhar

We review the physics of quarkonium production at high energy colliders, with a specific emphasis on production $via$ fragmentation. We discuss the fragmentation picture for the production of quarkonia at large-$p_T$ at the Tevatron and emphasise the importance of the colour-octet components of the quarkonium wave function which are included in the fragmenta

Kiwoon Choi, Eung Jin Chun, Hyungdo Kim

We examine in a generic context how the $μ$ problem can be resolved by means of a spontaneously broken gauge symmetry. We then focus on the new scheme based on a discrete gauge R symmetry which is spontaneously broken by nonperturbative hidden sector dynamics triggering supersymmetry breaking also. The possibility to suppress the dangerous baryon and/or lept

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

The $ϕ^4_3$ model at finite temperature is simulated on the lattice. For fixed $N_t$ we compute the transition line for $N_s \to \infty$ by means of Finite Size Scaling techniques. The crossings of a Renormalization Group trajectory with the transition lines of increasing $N_t$ give a well defined limit for the critical temperature in the continuum. By consi

Ray L. Renken

A block spin renormalization group approach is introduced which can be applied to dynamical triangulations in any dimension.

Margarita Garcia Perez, Pierre van Baal

We determine the one-loop correction to the anisotropy factor for the square Symanzik improved lattice action, extracted fromthe finite volume effective action for SU(N) gauge theories in the background of a zero-momentum gauge field. The result is smaller by approximately a factor 3 than the one-loop correction for the anisotropic Wilson action. We also com

Christoph Schiller

A structured collection of thought provoking conclusions about space and time is given. Using only the Compton wavelength lambda = hbar / m c and the Schwarzschild radius r_s = 2 G m / c^2, it is argued that neither the continuity of space-time nor the concepts of space-point, instant, or point particle have experimental backing at high energies. It is then

Normand Mousseau, Laurent J. Lewis

Using the recently-proposed ``activation-relaxation technique'' for optimizing complex structures, we develop a structural model appropriate to a-GaAs which is almost free of odd-membered rings, i.e., wrong bonds, and possesses an almost perfect coordination of four. The model is found to be superior to structures obtained from much more computer-int

Miguel A. Martin-Delgado

I review recent work and some new results, performed in collaboration with G. Sierra, on the Real-Space Renormalization group method applied to quantum spin lattice systems mainly in spatial dimensions one and two, and to spin ladders which are somehow in between. The first part of these notes is devoted to non-interacting systems in 1D and 2D and the role p

R. Lacaze, A. Morel, B. Petersson, J. Schroper

We present an investigation of the 2D attractive Hubbard model, considered as an effective model relevant to superconductivity in strongly interacting electron systems. We use both hybrid Monte Carlo simulations and existing hopping parameter expansions to explore the low temperature domain. The increaseof the static S-wave pair correlation with decreasing t

C. Steidel, M. Dickinson, D. Meyer, K. Adelberger

We present very deep WFPC2 images and FOS spectroscopy from the Hubble Space Telescope (HST) together with numerous supporting ground-based observations of the field of the quasar 3C 336 ($z_{em}=0.927$). The observations are designed to investigate the nature of galaxies producing metal line absorption systems in the spectrum of the QSO. Along a single line

Chigurupati Murali, Martin D. Weinberg

We study the dynamical evolution of disk and halo globular clusters in the Milky Way using a series of Fokker-Planck calculations combined with parametric statistical models. Our sample of 113 clusters with velocity data is predicted to descend from an initial population of 250 clusters, implying more than a factor of two decrease in population size due to e

Azita Valinia, Paul R. Shapiro, Hugo Martel, Ethan T. Vishniac

The gravitational instability of cosmological pancakes composed of collisionless dark matter in an Einstein-de Sitter universe is investigated numerically to demonstrate that pancakes are unstable with respect to fragmentation and the formation of filaments. A ``pancake'' is defined here as the nonlinear outcome of the growth of a 1D, sinusoidal, pla

Ray J. Weymann, Simon L. Morris, Meghan E. Gray, John B. Hutchings

We present the results of a GHRS program to monitor the absorption lines in the spectrum of the Seyfert 1 galaxy NGC 4151 caused by outflowing gas from the nucleus. Although we see subtle changes over the four year period in the GHRS spectra of the broader of the absorption features, the wavelength constancy of all the features is remarkable. The limits on t

Simon L. Morris

I review the results obtained using the GHRS on low redshift Lyman alpha absorbers. Until the advent of HST and the GHRS, the existence of such absorbers was doubted. The confirmation of their existence, in one of the first GHRS GTO team results to be published, must rank as one of the HSTs most interesting results. The GHRS resolution allows us to probe equ

Craig J. Copi

Observations of elemental abundances in the Galaxy have repeatedly shown an intrinsic scatter as a function of time and metallicity. The standard approach to chemical evolution does not attempt to address this scatter in abundances since only the mean evolution is followed. In this work the scatter is addressed via a stochastic approach to solving chemical e

Pierre-Yves Longaretti

The currently used linear and nonlinear lens inversion techniques are based on distortion estimators whose complicated source redshift dependence makes the influence of the redshift distribution of the sources difficult to take into account and to analyze. However, the lens equations can be explicitly averaged over the source redshift distribution by a suita

Guenter Sigl, Sangjin Lee, David N. Schramm, Paolo Coppi

Physics beyond the standard model might imply the cosmological production of particles with grand unification scale energies. Nucleons and gamma-rays from such processes are candidates for the cosmic rays observed beyond 100 EeV [10**(20) eV]. Using a new particle propagation code, we calculate the neutrino fluxes predicted by such scenarios if consistency w

Claudio Firmani, Xavier Hernández, Vladimir Avila-Reese

The galactic evolutionary theory is now sufficiently mature to provide information about the galaxy formation phase. From evolutionary models we establish a link between the present features of late type galaxies and the protogalactic density fluctuations. This link is used to estimate the fluctuation power spectrum amplitude at galactic scales. The agreemen

Alexander Kuznetsov

Let $C$ be a smooth projective curve of genus 0. Let $\FF$ be the variety of complete flags in an $n$-dimensional vector space $V$. Given an $(n-1)$-tuple $α$ of positive integers one can consider the space $\MMα$ of algebraic maps of degree $α$ from $C$ to $\FF$. This space has drawn much attention recently in connection with Quantum Cohomology. The space $

Maxim Nazarov

We apply the technique of affine Hecke algebras to the invariant theory of the "queer" Lie superalgebra $q_N$. We give explicit formulas for the elements of a distinguished basis in the centre of $U(q_N)$, determined by "vanishing" conditions. We evaluate the corresponding differential operators on $C^{N|N}\otimes C^{M|M}$. In particular, we

J. Wosiek, R. E. Janik

A new method is applied to solve the Baxter equation for three coupled, noncompact spins. Due to the equivalence with the system of three reggeized gluons, the intercept of the odderon trajectory is predicted for the first time, as the analytic function of the two relevant parameters.

D. Ivanov

The KZB equations for conformal blocks of the WZNW theory are written on the moduli space of holomorphic principal bundles on the surface. They become the multi-time Schroedinger equation for the nonstationary Hitchin system. From the known form of the equations we learn about the covariance of quantization with respect to changes of the coordinate frame.

Ofer Aharony, Shamit Kachru, Eva Silverstein

We present several new examples of nontrivial 4d N=1 superconformal field theories. Some of these theories exhibit exotic global symmetries, including non-simply laced groups (such as $F_4$). They are obtained by studying threebrane probes in F-theory compactifications on elliptic Calabi-Yau threefolds. The geometry of the compactification encodes in a simpl

Ilka Brunner, Monika Lynker, Rolf Schimmrigk

We consider splitting type phase transitions between Calabi-Yau fourfolds. These transitions generalize previously known types of conifold transitions between threefolds. Similar to conifold configurations the singular varieties mediating the transitions between fourfolds connect moduli spaces of different dimensions, describing ground states in M- and F-the

B. Bailey, E. L. Berger, L. E. Gordon

The two particle inclusive cross section for the reaction $p +\bar{p}\rightarrow γ+ c + X$ is studied in perturbative quantum chromodynamics at order $O(α^2_s)$. Differential distributions are provided for various observables, and a comparison is made with data from the CDF collaboration.

J. L. Hewett

We determine the ability of future experiments to observe supersymmetric contributions to the rare decays $B \to X_s γ$ and $B \to X_s l^+l^-$. A global fit to the Wilson coefficients which contribute to these decays is performed from Monte Carlo generated data. This fit is then compared to supersymmetric predictions for several different patterns of the sup

Bernd A. Kniehl

We review the present status of Higgs physics within the standard model and its extensions. First, we briefly summarize the current experimental exclusion limits from the direct searches with LEP1 and the Tevatron, and assess the discovery potential of LEP2. Then, we report the mass bounds resulting from global fits to the latest electroweak precision data,

Zoltán Trócsányi

The next-to-leading order three-jet cross section in hadron collisions is calculated in the simplified case when the matrix elements of all QCD subprocesses are approximated by the pure gluon matrix element. The longitudinally-invariant $k_\perp$ jet-clustering algorithm is used. The important property of reduced renormalization and factorization scale depen

Zoltán Nagy, Zoltán Trócsányi

A general method for calculating \NLO cross sections in perturbative QCD is presented. The algorithm is worked out for calculating $N$-jet cross sections in hadron-hadron collisions. The generalization of the scheme to performing caclulations for other QCD process, such as electron-positron annihilation or in deep inelastic scattering is also straightforward

P. Nurowski

We consider sphere bundles P and P' of totally null planes of maximal dimension and opposite self-duality over a 4-dimensional manifold equipped with a Weyl or Riemannian geometry. The fibre product PP' of P and P' is found to be appropriate for the encoding of both the selfdual and the Einstein-Weyl equations for the 4-metric. This encoding is r

A. Gamba, I. V. Kolokolov

We expose a functional integration method for the averaging of continuous products $\hat{P}_t$ of $N\times N$ random matrices. As an application, we compute exactly the statistics of the Lyapunov spectrum of $\hat{P}_t$. This problem is relevant to the study of the statistical properties of various disordered physical systems, and specifically to the computa

K. Mussawisade, T. Wichmann, K. W. Kehr

The temperature dependence of the diffusion coefficient of particles is studied on lattices with disorder. A model is investigated with both trap and barrier disorder that was introduced before by Limoge and Bocquet (1990 Phys. Rev. Lett. (65) 60) to explain an Arrhenian temperature-dependence of the diffusion coefficient in amorphous substances. We have use

A. Linde, V. Mukhanov

We present a class of very simple inflationary models of two scalar fields which leads to nongaussian isothermal perturbations with "blue" spectrum, n > 1. One of the models is inspired by supersymmetric theories where light scalar fields naturally acquire masses of the order of the Hubble constant H during inflation. Another model presumes that one

G. Holzwarth, R. Machleidt

We apply the strong $πNN$ form factor, which emerges from the Skyrme model, in the two-nucleon system using a one-boson-exchange (OBE) model for the nucleon-nucleon (NN) interaction. Deuteron properties and phase parameters of NN scattering are reproduced well. In contrast to the form factor of monopole shape that is traditionally used in OBE models, the Sky

Michael Farber

In this paper we suggest a new general formalism for studying the invariants of polyhedra and manifolds comming from the theory of von Neumann algebras. First, we examine generality in which one may apply the construction of the extended abelian category, which was suggested in the previous publications of the author, using the ideas of P.Freyd. This leads t

M. Braverman, M. Farber

We establish an equivariant generalization of the Novikov inequalities which allow to estimate the topology of the set of critical points of a closed basic invariant form by means of twisted equivariant cohomology of the manifold. We apply these inequalities to study cohomology of the fixed points set of a symplectic torus action. We show that in this case o

Yasuhide Sota, Shingo Suzuki, Kei-ichi Maeda

We examine the effect of local matter on the chaotic behavior of a relativistic test particle in non-vacuum static axisymmetric spacetimes. We find that the sign of the sectional curvature in the geodesic deviation equation defined by the Riemann curvature does not always become a good tool to judge the occurrence of chaos in the non-vacuum case. However, we

Bruce Ritzi, Graciela Gelmini

We investigate the existence of bound states of baryons in a kaon condensate using chiral mean field theory. The interactions are described by an effective SU(3)_L X SU(3)_R chiral lagrangian where terms of higher order in density, baryon momentum, and kaon mass are suppressed by powers of the symmetry breaking scale, Lambda. We take up to next to leading or

J. T. Liu, D. F. Wang

The integrability of the one-dimensional long range supersymmetric t-J model has previously been established for both open systems and those closed by periodic boundary conditions through explicit construction of its integrals of motion. Recently the system has been extended to include the effect of magnetic flux, which gives rise to a closed chain with twis

Edmond L. Berger, Xiaofeng Guo, Jianwei Qiu

We show that the conventionally defined partonic cross section for the production of isolated prompt photons is not an infrared safe quantity. We work out the case of $e^+e^-\toγ+ X$, and discuss implications for hadron reactions.

Tevian Dray

We discuss Einstein's field equations in the presence of signature change using variational methods, obtaining a generalization of the Lanczos equation relating the distributional term in the stress tensor to the discontinuity of the extrinsic curvature. In particular, there is no distributional term in the stress tensor, and hence no surface layer, prec

Tevian Dray, George Ellis, Charles Hellaby, Corinne Manogue

The use of proper ``time'' to describe classical ``spacetimes'' which contain both Euclidean and Lorentzian regions permits the introduction of smooth (generalized) orthonormal frames. This remarkable fact permits one to describe both a variational treatment of Einstein's equations and distribution theory using straightforward generalizat

Tevian Dray, Charles Hellaby

Kossowski and Kriele derived boundary conditions on the metric at a surface of signature change. We point out that their derivation is based not only on certain smoothness assumptions but also on a postulated form of the Einstein field equations. Since there is no canonical form of the field equations at a change of signature, their conclusions are not inesc

N. S. Ananikian, S. K. Dallakian

The chaotic properties of the three-site antiferromagnetic Ising model on Husimi tree are investigated in magnetic field. Macroscopic quantity of three-site antiferromagnetic Ising model is generated by one dimensional map. It is shown that in certain parameter setting strange attractors of this map exhibit multifractal scaling. By applying thermodynamic for

E. Bertin, M. Dennefeld, M. Moshir

We analyse a Far InfraRed (FIR) catalogue of galaxies at 60 microns with a flux limit of approx. 110 mJy, extracted from a deep subsample of the IRAS Faint Source Survey. Monte-Carlo simulations and optical identification statistics are used to put constraints on the evolution of galaxies in the FIR. We find evidence for strong evolution of IRAS galaxies, in

Sergio Gelato, Fabio Governato

Models of galaxy formation ultimately aim at reproducing the _observed_ properties of galaxies. We report on work in progress to predict luminosities, colours and morphologies of field objects of various masses through N-body + Smoothed Particle Hydrodynamics simulations. We describe our method, illustrate the effects of varying the star formation assumption

W. J. G. de Blok, Stacy McGaugh

Low Surface Brightness (LSB) galaxies form a large population of disc galaxies that extend the Hubble sequence towards extreme late-types. They are only slowly evolving, and still in an early evolutionary state. The Tully-Fisher relation and rotation curves of LSB galaxies both show that LSB galaxies are very dark-matter dominated with respect to ``normal&#3

Andrew R Liddle, Pedro T P Viana

The formation of structure in the Universe offers some of the most powerful evidence in favour of the existence of dark matter in the Universe. We summarize recent work by ourselves and our collaborators, using linear and quasi-linear theory to probe the allowed parameter space of structure formation models with perturbations based on the inflationary cosmol

K. J. Joshi, F. A. Rasio

We present a general method for determining the masses and orbital parameters of binary millisecond pulsars with long orbital periods (P_orb >> 1 yr), using timing data in the form of pulse frequency derivatives. We apply our method to analyze the properties of the second companion in the PSR B1620-26 triple system. We use the latest timing data for this sys

Bernd Sturmfels

This article will appear in the proceedings of the AMS Summer Institute in Algebraic Geometry at Santa Cruz, July 1995. The topic is toric ideals, by which I mean the defining ideals of subvarieties of affine or projective space which are parametrized by monomials. Numerous open problems are given.

Marco Matone

We construct modular invariants on the moduli space of quantum vacua of N=2 SYM with gauge group SU(2). We also introduce a nonchiral function K which is expressed in terms of the Seiberg-Witten and Poincare' metrics. It turns out that K has all the expected properties of the next to leading term in the Wilsonian effective action whose modular properties

H. Nunokawa, Y. -Z. Qian, G. M. Fuller

We discuss the effects of resonant spin-flavor precession (RSFP) of Majorana neutrinos on heavy element nucleosynthesis in neutrino-heated supernova ejecta and the dynamics of supernovae. In assessing the effects of RSFP, we explicitly include matter-enhanced (MSW) resonant neutrino flavor conversion effects where appropriate. We point out that for plausible

R. Akhoury, V. I. Zakharov

We present a sketchy review of renormalon-based phenomenology. In particular, the leading, 1/Q corrections to various observables, KLN cancellations for power-suppressed corrections and the fixation of operator matrix elements are highlighted.

Qian Xie, Wen-Qing Zhang, Nan-xian Chen

We present a systematical method for obtaining analytical long-range embedded-atom potentials based on the lattice-inversion method. The potentials converge faster (exponentially) than Sutton and Chen's power-law potentials (Philos. Mag. Lett. 61, 2480(1990)). An interesting relationship between the embedded-atom method and the universal binding energy e

Paolo Furlan, Ludmil K. Hadjiivanov, Ivan T. Todorov

The canonical quantization of the WZNW model provides a complete set of exchange relations in the enlarged chiral state spaces that include the Gauss components of the monodromy matrices. Regarded as new dynamical variables, the elements of the latter cannot be identified -- they satisfy different exchange relations. Accordingly, the two dimensional theory e

E. Eisenberg, Y. Ashkenazy

We study the tunneling through an oscillating delta barrier. Using time periodicity of the model, the time-dependent Schrödinger equation is reduced to a simple but infinite matrix equation. Employing Toeplitz matrices methods, the infinite matrix is replaces by a $3\times 3$ matrix, allowing an analytical solution. Looking at the frequency dependence of the

C. Klimcik, P. Severa

Aspects of Poisson-Lie T-duality are reviewed in more algebraic way than in our, rather geometric, previous papers. As a new result, a moment map is constructed for the Poisson-Lie symmetry of the system consisting of open strings propagating in a Poisson-Lie group manifold.

T. Mart, L. Tiator, D. Drechsel, C. Bennhold

Kaon photoproduction on He3, gamma + He3 --> K+ + Hypertriton, is studied in the framework of the impulse approximation. Realistic He3 wave functions obtained as solutions of Faddeev equations with the Reid soft-core potential are used along with different Hypertriton wave functions. Results are compared for several elementary operator models, which can succ

Zengo Tsuboi

It is known that a family of transfer matrix functional equations, the T-system, can be compactly written in terms of the Cartan matrix of a simple Lie algebra. We formally replace this Cartan matrix of a simple Lie algebra with that of an affine Lie algebra, and then we obtain a system of functional equations different from the T-system. It may be viewed as

Peter Shor, Raymond Laflamme

We derive a relationship between two different notions of fidelity (entanglement fidelity and average fidelity) for a completely depolarizing quantum channel. This relationship gives rise to a quantum analog of the MacWilliams identities in classical coding theory. These identities relate the weight enumerator of a code to the one of its dual and, with linea

B. Abdesselam, A. Chakrabarti, R. Chakrabarti

By solving a set of recursion relations for the matrix elements of the ${\cal U}_h(sl(2))$ generators, the finite dimensional highest weight representations of the algebra were obtained as factor representations. Taking a nonlinear combination of the generators of the two copies of the ${\cal U}_h(sl(2))$ algebra, we obtained ${\cal U}_h(so(4))$ algebra. The

A. J. Buchmann, E. Hernandez, Amand Faessler

We calculate the electromagnetic moments and radii of the Delta(1232) in the nonrelativistic quark model, including two-body exchange currents. We show that two-body exchange currents lead to nonvanishing Delta and N-->Delta transition quadrupole moments even if the wave functions have no D-state admixture. The usual explanation based on the single-quark tra

F. Catara, E. G. Lanza, M. A. Nagarajan, A. Vitturi

Quadrupole transition densities in neutron-rich nuclei in the vicinity of the neutron drip-line are calculated in the framework of the Random Phase Approximation. The continuum is treated by expansion in oscillator functions. We focus on the states which contribute to the usual Giant Quadrupole Resonance, and not on the low-lying strength which is also expec

K. Rutz, J. A. Maruhn, P. -G. Reinhard, W. Greiner

The symmetric and asymmetric fission path for 240Pu, 232Th, and 226Ra is investigated within the relativistic mean field model. Standard parametrizations which are well fitted to nuclear ground state properties are found to deliver reasonable qualitative and quantitative features of fission, comparable to similar nonrelativstic calculations. Furthermore, sta

P. G. Warren, S. Albergo, J. M. Alexander, F. Bieser

The mean transverse kinetic energies of the fragments formed in the interaction of 1 A GeV Au+C have been determined. An energy balance argument indicates the presence of a collective energy which increases in magnitude with increasing multiplicity and accounts for nearly half of the measured mean transverse kinetic energy. The radial flow velocity associate

Keith Burns, Gabriel Paternain

Let $M$ be a compact $C^{\infty}$ Riemannian manifold. Given $p$ and $q$ in $M$ and $T>0$, define $n_{T}(p,q)$ as the number of geodesic segments joining $p$ and $q$ with length $\leq T$. Mañé showed that the exponential growth rate of the integral of $n_{T}(p,q)$ over $M \times M$ is the topological entropy of the geodesic flow of $M$. In the present paper

Howard Becker, Randall Dougherty

Larman showed that any closed subset of the plane with uncountable vertical cross-sections has aleph_1 disjoint Borel uniformizing sets. Here we show that Larman's result is best possible: there exist closed sets with uncountable cross-sections which do not have more than aleph_1 disjoint Borel uniformizations, even if the continuum is much larger than aleph

D. Bazeia, J. R. S. Nascimento

We investigate the effective potential for Abelian Maxwell--Chern--Simons systems. The calculations follow an alternate approach, recently proposed as a gauge invariant formulation of the effective potential, constructed in terms of a gauge invariant order parameter. We compare the results with another investigation, obtained within a standard route of calcu

Mariano Cadoni

We investigate the behavior of generic, matter-coupled, 2D dilaton gravity theories under dilaton-dependent Weyl rescalings of the metric. We show that physical observables associated with 2D black holes, such as the mass, the temperature and the flux of Hawking radiation are invariant under the action of both Weyl transformations and dilaton reparametrizati

E. Alfinito, M. S. Causo, G. Profilo, G. Soliani

We consider a nonlinear field equation which can be derived from a binomial lattice as a continuous limit. This equation, containing a perturbative friction-like term and a free parameter $γ$, reproduces the Toda case (in absence of the friction-like term) and other equations of physical interest, by choosing particular values of $γ$. We apply the symmetry a

Masafumi Fukuma, Shigeaki Yahikozawa

We study the combinatorics of solitons in $D<2$ (or $c<1$) string theory. The weights in the summation over multi-solitons are shown to be automatically determined if we further require that the partition function with soliton background be a $τ$ function of the KP hierarchy, in addition to the $W_{1+\infty}$ constraint.

Gernot Münster, Harald Grießhammer, Dirk Lehmann

These lecture notes want to illustrate the close connection between statistical mechanics and field theory not only on the formal level, i.e. that many concepts of one area can easily be taken over to the other one, but also on the level of actual calculations. To this purpose, the last section will demonstrate that a special statistical system, the binary f

Kazuto Oshima

We give an elementary derivation of the de Rham cohomology of SO(n) in terms of supersymmetric quantum mechanics. Our analysis is based on Witten&#39;s Morse theory. We show reflection symmetries of the theory are useful to select true vacuums. The number of the selected vacuums will agree with the de Rham cohomology of SO(n).

J. F. Gunion, J. Kelly

We demonstrate that supersymmetric decays, as typified by the predictions of several GUT-scale boundary condition choices, do not prevent detection of $Z^* \to H^0A^0,H^+H^-$, at a $1-4$ TeV $e^+e^-$ or $μ^+μ^-$ collider operating at anticipated luminosity. For much of parameter space the relative branching ratios for various SUSY and non-SUSY decays can be

Christian Y. Cardall, George M. Fuller

We discuss neutrino oscillations in curved spacetime. Our heuristic approach can accomodate matter effects and gravitational contributions to neutrino spin precession in the presence of a magnetic field. By way of illustration, we perform explicit calculations in the Schwarzschild geometry. In this case, gravitational effects on neutrino oscillations are int

Louis J. Clavelli, Levan R. Surguladze

The results of calculation of light gluino contributions to Gamma(Z--->hadrons) and Gamma(tau--->hadrons) to O(alpha_s^3) are presented. The net effect in the case of Z decay is noticeable. For the tau width the effect is very large and, if a light gluino exists, suggests that alpha_s increases by more than 15% relative to the Standard Model analysis.