October 1993 arXiv papers — page 3

Angel Sanchez, Maria J. Bernal, Jose M. Riveiro

We introduce an aggregation model for general electrochemical deposition experiments. Its most relevant feature is that it includes the overall effect of strong applied electric fields and therefore applies to non-equilibrium situations. We compare our model to experiments on CoP dendritic growth with very good agreement: The model accurately reproduces the

T. Blum

A variational method that allows for replica-symmetry breaking is applied to directed polymers in an (N+1)-dimensional disordered medium. The noise studied here has gaussian correlations, i.e. it is short-ranged. In dimensions N<2, the variational scheme yields only a strong-coupling phase and anomalous diffusion; while in dimensions N>2 it shows weak- and s

C. Pich, F. Schwabl

We calculate the Néel temperature $T_N$ for two-dimensional isotropic dipolar Heisenberg antiferromagnets via linear spin-wave theory and a high temperature expansion, employing the method of Callen. The theoretical predictions for $T_N$ for K$_2$MnF$_4$, Rb$_2$MnF$_4$, Rb$_2$MnCl$_4$ and (CH$_3$NH$_3$)$_2$MnCl$_4$ are in good agreement with the measured val

Xiaochun Luo

Information about the physical processes that generate the primordial fluctuations in the early universe can be gained by testing the Gaussian nature of the fluctuations through cosmic microwave background radiation (CBR) temperature anisotropy experiments. One of the crucial aspects of density perturbations that are produced by the standard inflation scenar

Geoffrey Harris

We study percolation on the worldsheets of string theory for $c=0,1/2,1$ and $2$. For $c<1$ we find that critical exponents measured from simulations agree quite well with the theoretical values. For $c=1$ we show how log corrections determined from the exact solution reconcile numerical results with the KPZ predictions. We extend this analysis to the large

Mark Bowick, Marco Falcioni, Geoffrey Harris, Enzo Marinari

To investigate the properties of $c=1$ matter coupled to $2$d{--}gravity we have performed large-scale simulations of two copies of the Ising Model on a dynamical lattice. We measure spin susceptibility and percolation critical exponents using finite-size scaling. We show explicitly how logarithmic corrections are needed for a proper comparison with theoreti

C. M. Hull

The gauging of isometries in general sigma-models which include fermionic terms which represent the interaction of strings with background Yang-Mills fields is considered. Gauging is possible only if certain obstructions are absent. The quantum gauge anomaly is discussed, and the (1,0) supersymmetric generalisation of the gauged action given.

B. Rusakov

Wilson loop averages of pure gauge QCD at large N on a sphere are calculated by means of Makeenko-Migdal loop equation.

A. H. Castro Neto, Eduardo H. Fradkin

We study, via bosonization, the Landau fixed point for the problem of interacting spinless fermions near the Fermi surface in dimensions higher than one. We rederive the bosonic representation of the Fermi operator and use it to find the general form of the fermion propagator for the Landau fixed point. Using a generalized Bogoliubov transformation we diagon

David Coulson, Pedro Ferreira, Paul Graham, Neil Turok

High resolution maps of the anisotropy of the microwave sky will yield invaluable clues as to the mechanisms involved in cosmic structure formation. One fundamental question they should answer is whether the fluctuations were Gaussian random noise, as predicted in inflationary models, or were nonGaussian as in theories based on symmetry breaking and cosmic d

Kenji Kajiwara, Yasuhiro Ohta, Junkichi Satsuma, Basil Grammaticos

We present a class of solutions to the discrete Painlevé-II equation for particular values of its parameters. It is shown that these solutions can be expressed in terms of Casorati determinants whose entries are discrete Airy functions. The analogy between the $τ$ function for the discrete P$_{\rm \romanno2}$ and the that of the discrete Toda molecule equati

Giuseppe Albertini

The sector of zero $Z_{N}$-charge is studied for the ferromagnetic (FM) and antiferromagnetic (AFM) version of the $Z_{N}\times Z_{2}$ invariant Fateev-Zamolodchikov quantum spin chain. We conjecture that the relevant Bethe ansatz equations should admit, beside the usual string-like solutions, exceptional multiplets, and a number of non-physical solutions. O

Celeghini, S. De Martino, S. De Siena, M. Rasetti

By resorting to the Fock--Bargmann representation, we incorporate the quantum Weyl--Heisenberg ($q$-WH) algebra into the theory of entire analytic functions. The main tool is the realization of the $q$--WH algebra in terms of finite difference operators. The physical relevance of our study relies on the fact that coherent states (CS) are indeed formulated in

Philip C. Argyres, S. -H. Henry Tye

Scattering amplitudes of the spin-4/3 fractional superstring are shown to satisfy spurious state decoupling and cyclic symmetry (duality) at tree-level in the string perturbation expansion. This fractional superstring is characterized by the spin-4/3 fractional superconformal algebra---a parafermionic algebra studied by Zamolodchikov and Fateev involving chi

G. Delfino, G. Mussardo

The two-point correlation function of the stress-energy tensor for the $Φ_{1,3}$ massive deformation of the non-unitary model ${\cal M}_{3,5}$ is computed. We compare the ultraviolet CFT perturbative expansion of this correlation function with its spectral representation given by a summation over matrix elements of the intermediate asymptotic massive particl

Hiromichi Nakazato

A new Langevin equation with a field-dependent kernel is proposed to deal with bottomless systems within the framework of the stochastic quantization of Parisi and Wu. The corresponding Fokker-Planck equation is shown to be a diffusion-type equation and is solved analytically. An interesting connection between the solution with the ordinary Feynman measure,

J. S. Dowker

The standard formula for the change in the effective action under a conformal transformation is extended to the case when the boundary is piecewise smooth. We then find the functional determinants of the scalar Laplacian on regions of the plane obtained by stereographic projection of the fundamental domains on an orbifolded two-sphere. Examples treated are t

B. Machet

We study a dynamically broken U(1) &#34;left&#34; gauge theory endowed with a composite scalar doublet (one scalar and one pseudoscalar); its Lagrangian only differs from that of an abelian `Standard Model&#39; by the addition of a derivative coupling between a Wess-Zumino field, linked to the previous scalars, and the fermionic current. Yet, in the Feynman

E. Sezgin

We review various aspects of a fermionic gauge symmetry, known as the $κ$--symmetry, which plays an important role in formulations of superstrings, supermembranes and higher dimensional extended objects. We also review some aspects of the connection between $κ$--symmetric theories and their twistor-like formulations.

P. M. Nadolsky, S. M. Troshin, N. E. Tyurin

We consider the physics motivations and perspectives for the study of spin phenomena at the future high energies accelerators. The possibilities to use the already operating machines are also discussed. It is emphasized that the present status of QCD spin studies necessarily requires a wide range of spin measurements

J. Kambor, B. R. Holstein

Agreement between the experimental value $Γ(K_S\rightarrow γγ)$ and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand the one-loop prediction for the closely related process $K_L\rightarrow π^0γγ$ has been found to be a factor three below the experimental value. Using the

X. Artru

We present the principles of the measurement of the quark transversity distributions in semi-inclusive deep inelastic electron scattering, which form the basis of HELP and one of the ELFE proposals. A string model for Collins-type asymmetry in polarized quark fragmentation function is proposed. A possible role of the Collins effect in the single spin asymmet

V. Barone, M. Genovese, N. N. Nikolaev, E. Predazzi

We discuss the updated NMC determination of $F_2^n/F_2^p$ and $F_2^p - F_2^n$. Shadowing effects in deuterium make the structure functions determined by the NMC sensibly different from the true ones in the low--$x$ region. We show that the departure of $F_2^n/F_2^p$ and $F_2^p-F_2^n$ from the Regge expectations at small $x$ observed by the NMC likely disappe

Miriam Leurer, Yosef Nir, Nathan Seiberg

The smallness of the quark sector parameters and the hierarchy between them could be the result of a horizontal symmetry broken by a small parameter. Such an explicitly broken symmetry can arise from an exact symmetry which is spontaneously broken. Constraints on the scales of new physics arise {}from new flavor changing interactions and {}from Landau poles,

D. Boyanovsky, H. J. de Vega, R. Holman

We derive the effective equations for the out of equilibrium time evolution of the order parameter and the fluctuations of a scalar field theory in spatially flat FRW cosmologies.The calculation is performed both to one-loop and in a non-perturbative, self-consistent Hartree approximation.The method consists of evolving an initial functional thermal density

Harry J. Lipkin

The parton model, a zero-order approximation in many treatments, is shown to be a ``semiclassical&#34; model whose results for certain averages also hold (correspondence principle) in quantum mechanics. Algebraic techniques developed for the Mössbauer effect exploit simple features of commutators to obtain sum rules showing the validity of the parton model f

Harry J. Lipkin

One of the greatest challenges for particle physics in the 1990&#39;s is understanding the broken symmetry of CP violation. It is now almost 30 years since the discovery in 1964 of the $K_{L} \rightarrow 2π$ decay. What has happened since? Why has there been no significant new experimental input in this long period? The original $K_{L} \rightarrow 2π$ decay

S. Mukherjee, N. K. Dadhich

A chaotic model of the early universe within the framework of the singularity-free solutions of Einstein&#39;s equation is suggested. The evolution of our universe at its early stage, starting out as a small domain of the parent universe, is governed by the dynamics of a classical scalar field $ϕ$ . If in any such domain, larger than Planck length,$\dot ϕ$ h

David A. Huse, Leo R. Radzihovsky

Thermal fluctuations and disorder play an essential role in high-T$_c$ superconductors. After reviewing the mean-field phase diagram we describe significant modifications that result when the effects of finite temperature and disorder are incorporated. Thermal fluctuations cause the melting of the Abrikosov flux line lattice into a vortex liquid at high temp

Paul J. Mancinelli, Amos Yahil, Galit Ganon, Avishai Dekel

Nonlinear approximations to problems with mixed boundary conditions are useful for predicting large-scale streaming velocities from the density field, or vice-versa. We evaluate the schemes of Bernardeau \cite{bernardeau92}, Gramann \cite{gramann93}, and Nusser \etal \cite{nusser91}, using smoothed density and velocity fields obtained from $N$-body simulatio

Y. Alhassid, D. J. Dean, S. E. Koonin, G. Lang

We present a practical solution to the &#34;sign problem&#34; in the auxiliary field Monte Carlo approach to the nuclear shell model. The method is based on extrapolation from a continuous family of problem-free Hamiltonians. To demonstrate the resultant ability to treat large shell-model problems, we present results for 54Fe in the full fp-shell basis using

Alexander Turbiner

A certain generalization of the algebra $gl(N,{\bf R})$ of first-order differential operators acting on a space of inhomogeneous polynomials in ${\bf R}^{N-1}$ is constructed. The generators of this (non)Lie algebra depend on permutation operators. It is shown that the Hamiltonian of the $N$-body Calogero model can be represented as a second-order polynomial

B. Ananthanarayan, Saurabh D. Rindani

It is pointed out that certain CP-odd momentum correlations in the production and subsequent decay of tau pairs in $e^+e^-$ collisions get enhanced when the $e^-$ is longitudinally polarized. Analytic expressions for these correlations are obtained for the single-pion decay mode of $τ$ when $τ^+τ^-$ have a ``weak&#34; dipole form factor (WDFF) coupling to $Z

G. &#39;t Hooft

The requirement that physical phenomena associated with gravitational collapse should be duly reconciled with the postulates of quantum mechanics implies that at a Planckian scale our world is not 3+1 dimensional. Rather, the observable degrees of freedom can best be described as if they were Boolean variables defined on a two-dimensional lattice, evolving w

R. D. Daniels, G. M. Shore

Photons propagating in curved spacetime may, depending on their direction and polarisation, have velocities exceeding the ``speed of light&#39;&#39; c. This phenomenon arises through vacuum polarisation in QED and is a tidal gravitational effect depending on the local curvature. It implies that the Principle of Equivalence does not hold for interacting quant

D. I. Kazakov, S. N. Solodukhin

We consider the deformation of the Schwarzschild solution in general relativity due to spherically symmetric quantum fluctuations of the metric and the matter fields. In this case, the 4D theory of gravity with Einstein action reduces to the effective two-dimensional dilaton gravity. We have found that the Schwarzschild singularity at $r=0$ is shifted to the

Albert Schwarz

This short note is closely related to Sen-Zwiebach paper on gauge transformations in Batalin-Vilkovisky theory (hep-th 9309027). We formulate some conditions of physical equivalence of solutions to the quantum master equation and use these conditions to give a very transparent analysis of symmetry transformations in BV-approach. We prove that in some sense e

Friedemann Brandt

For a large class of gauge theories a nilpotent BRS-operator $s$ is constructed and its cohomology in the space of local functionals of the off-shell fields is shown to be isomorphic to the cohomology of $\4s=s+d$ on functions $f(\4C,\PH)$ of tensor fields $\PH$ and of variables $\4C$ which are constructed of the ghosts and the connection forms. The result a

I. Bakas

We present a Lagrangian description of the $SU(2)/U(1)$ coset model perturbed by its first thermal operator. This is the simplest perturbation that changes sign under Krammers--Wannier duality. The resulting theory, which is a 2--component generalization of the sine--Gordon model, is then taken in Minkowski space. For negative values of the coupling constant

I. Bakas

We consider a bosonic string propagating in 4--dim Minkowski space. We show that in the orthonormal gauge the classical system exhibits a hidden $W_{\infty}$ chiral symmetry, arising from the equivalence of its transverse modes with the $SU(2)/U(1)$ coset model defined on the string world--sheet. Generalizations to other string backgrounds are proposed. We a

Michael R. Gallis

Decoherence and dissipation in quantum systems has been studied extensively in the context of Quantum Brownian Motion. Effective decoherence in coarse grained quantum systems has been a central issue in recent efforts by Zurek and by Hartle and Gell-Mann to address the Quantum Measurement Problem. Although these models can yield very general classical phenom

H. Hinrichsen, P. P. Martin, V. Rittenberg, M. Scheunert

Using $U_q[SU(2)]$ tensor calculus we compute the two-point scalar operators (TPSO), their averages on the ground-state give the two-point correlation functions. The TPSOs are identified as elements of the Temperley-Lieb algebra and a recurrence relation is given for them. We have not tempted to derive the analytic expressions for the correlation functions i

G. W. Gibbons, D. Kastor, L. A. J. London, P. K. Townsend

We show that the `instantonic&#39; soliton of five-dimensional Yang-Mills theory and the closely related BPS monopole of four-dimensional Yang-Mills/Higgs theory continue to be exact static, and stable, solutions of these field theories even after the inclusion of gravitational, electromagnetic and, in the four-dimensional case, dilatonic interactions, provi

Jerzy Lukierski, Henri Ruegg

The $κ$-deformation of the D-dimensional Poincaré algebra $(D\geq 2)$ with any signature is given. Further the quadratic Poisson brackets, determined by the classical $r$-matrix are calculated, and the quantum Poincaré group &#34;with noncommuting parameters&#34; is obtained.

Jean-Loup Gervais

Ideas recently put forward by Y. Matsuo and the author are summarized on the example of the simplest ($W_3$) generalization of two-dimensional gravity. These notes are based on lectures given at the workshop `` Strings, Conformal Models and Topological Field Theories&#39;&#39;, Cargese 12-21 May 1993; and at the meeting ``String 93&#39;&#39;, Berkeley, 24-29

Martin Cederwall

A very basic introduction is given to the rôles of division algebras and the related sphere algebras concerning the structure of space-time in the dimensionalities $D\is 3,4,6$ and $10$, with special emphasis on twistors transformations for light-likeness conditions and Hopf maps, together with some outlook for particle and string theory.

I. I. Balitsky, V. M. Braun, A. V. Kolesnichenko

We clarify conflicting results in the literature on coefficient functions in front of higher twist operators contributing to the parton sum rules for deep inelastic scattering from polarized targets. The necessary corrections do not affect our calculations of matrix elements, published in Phys.Lett.B242(1990)245, but change final estimates of the $\sim 1/Q^2

Maurice H. P. M. van Putten

The theory of ideal Yang-Mills fluids (IYMF; a Yang-Mills field coupled to a fluid in the limit of infinite conductivity) is embedded in symmetric hyperbolic form. This yields both causality and well-posedness of initial value problems in this theory. The embedding is based on a covariant, constraint-free divergence formulation of IYMF, developped by the aut

S. M. Bilenky, C. Giunti

It is shown that future solar neutrino experiments (SNO, Super-Kamiokande and others), in which high energy neutrinos will be detected (mostly from 8B decay), may allow to answer in a model independent way the question whether there are transitions of solar $ν_e$&#39;s into sterile states. No assumptions about the initial flux of 8B neutrinos are done. Lower

Harry Contopanagos, George Sterman

We present a new resummation formula for the Drell-Yan cross section. The formal resummation of threshold corrections in Drell-Yan hard-scattering functions produces an exponent with singularities from the infrared pole of the QCD running coupling. Our reformulation treats such `infrared renormalons&#39; by a principal value prescription, analogous to a modi

S. Herrlich, U. Nierste

We calculate the next-to-leading order short distance QCD corrections to the coefficient $η_1$ of the effective $ΔS = 2$ hamiltonian in the standard model. This part dominates the short distance contribution $(Δm_K)^{\rm SD}$ to the $K_L$ -- $K_S$ mass difference. The next-to-leading order result enhances $η_1$ and $(Δm_K)^{\rm SD}$ by 20\% compared to the l

G. V. Dass, K. V. L. Sarma

We explore the possibility that the existing data on like-sign dileptons at the $Υ(4S)$ resonance consist of events arising from $B_{d}^0 -\bar B_{d}^0$ mixing and also from $ΔB = - ΔQ$ transitions. The consequences of these nonstandard transitions for certain time-asymmetries which are likely to be measured at the $B$ factories are studied.

H. Weigel, R. Alkofer, H. Reinhardt

For the Nambu--Jona--Lasinio (NJL) model in the proper time regularization scheme the chiral soliton is investigated for the case of three flavors within the framework of the bound state approach to strangeness. For this purpose meson fluctuations off the non--strange soliton are considered. For the kaon P--wave channel the emerging Bethe--Salpeter equation

L. Karkkainen, R. Lacaze, P. Lacock, B. Petersson

We measure the critical exponents of the three dimensional Gross-Neveu model with two four-component fermions. The exponents are inferred from the scaling behaviour of observables on different lattice sizes. We also calculate the exponents, through a second order epsilon-expansion around 4d, for the three dimensional Higgs-Yukawa model, which is expected to

P. W. Stephenson

I discuss some calculations of the running coupling in SU($N$) gauge theories from lattice simulations, centering on the work of the UKQCD collaboration. This talk is introductory in nature; full details have been published elsewhere.

H. David Politzer

Two formulations of quantum mechanics, inequivalent in the presence of closed timelike curves, are studied in the context of a soluable system. It illustrates how quantum field nonlinearities lead to a breakdown of unitarity, causality, and superposition using a path integral. Deutsch&#39;s density matrix approach is causal but typically destroys coherence.

R. Gambini, J. Pullin

We show that the exponential of the Gauss (self) linking number of a knot is a solution of the Wheeler-DeWitt equation in loop space with a cosmological constant. Using this fact, it is straightforward to prove that the second coefficient of the Jones Polynomial is a solution of the Wheeler-DeWitt equation in loop space with no cosmological constant. We perf

D. Braak

The selfconsistent approach to the 2D Ising Model with quenched random bonds is extended to the full lattice theory of four real fermions. The additional degrees of freedom, neglected in the renormalization-group theory, lead to a new phase between the ferromagnetic and the paramagnetic phase. The disorder averaged spin-spin correlation function decays expon

A. Dobry, A. Greco, J. Lorenzana, J. Riera

We have studied the three-band Peierls-Hubbard model describing the Cu-O layers in high-T$_c$ superconductors by using Lanczos diagonalization and assuming infinite mass for the ions. When the system is doped with one hole, and when the electron-lattice coupling is greater than a critical value, we found that the oxygens around one Cu contract and the hole s

F. R. Boffi, L. Stanghellini

We calculate filling factors (${\varepsilon}$) and ionized masses (M$_{\rm i}$) for a total of 84 galactic and extragalactic planetary nebulae (PNe) at known distances. To do these calculations, we have chosen forbidden line electron densities, observed angular diameters, and H$β$ fluxes, from the most recent measurements available in the literature. Statist

Emil Nissimov, Svetlana Pacheva

This is mainly a brief review of some key achievements in a `hot&#39;&#39; area of theoretical and mathematical physics. The principal aim is to outline the basic structures underlying {\em integrable} quantum field theory models with {\em infinite-dimensional} symmetry groups which display a radically new type of {\em quantum group} symmetries. Certain part

John F. Donoghue

I argue that the leading quantum corrections, in powers of the energy or inverse powers of the distance, may be computed in quantum gravity through knowledge of only the low energy structure of the theory. As an example, I calculate the leading quantum corrections to the Newtonian gravitational potential.

C. R. Nappi, E. Witten

We present a conformal field theory which desribes a homogeneous four dimensional Lorentz-signature space-time. The model is an ungauged WZW model based on a central extension of the Poincaré algebra. The central charge of this theory is exactly four, just like four dimensional Minkowski space. The model can be interpreted as a four dimensional monochromatic

E. Marinari, G. Parisi, F. Ritort

We study the $3d$ Ising spin glass with $\pm 1$ couplings. We introduce a modified local action. We use finite size scaling techniques and very large lattice simulations. We find that our data are compatible both with a finite $T$ transition and with a $T=0$ singularity of an unusual type.

Alexander Moroz

In the case of electromagnetic waves it is necessary to distinguish between inward and outward on-shell integral equations. Both kinds of equation are derived. A correct implementation of the photonic KKR method then requires the inward equations and it follows directly from them. A derivation of the KKR method from a variational principle is also outlined.

J. F. van Diejen

Recent results are surveyed pertaining to the complete integrability of some novel n-particle models in dimension one. These models generalize the Calogero-Moser systems related to classical root systems. Quantization leads to difference operators instead of differential operators.

Wolfgang Bauer, Vladimir Zelevinsky, Peter Schuck

We study the conditions under which the nucleons inside a deformed nucleus can undergo chaotic motion. To do this we perform self-consistent calculations in semiclassical approximation utilizing a multipole-multipole interaction of the Bohr-Mottelson type for quadrupole and octupole deformations. For the case of harmonic and non-harmonic static potentials, w

H. Henning, J. Adam, P. U. Sauer, A. Stadler

Theoretical predictions for the deuteron and the isoscalar trinucleon charge form factors are compared. Correlations between them are found. Linear relations hold for the position of the diffraction minimum and for the position and height of the secondary maximum. The linear relation for the diffraction minimum misses the experimental data.

Kazuhiro Tanaka

The energy spectrum of nucleons in high-density nuclear matter is investigated in the framework of relativistic meson-nucleon many-body theory, employing the $1/N$ expansion method. The coupling of the nucleon with the particle-hole excitations in the medium flattens the spectra in the vicinity of the Fermi surface. The effect grows logarithmically for incre

Nicola Maggiore, Martin Schaden

We consider a model which effectively restricts the functional integral of Yang--Mills theories to the fundamental modular region. Using algebraic arguments, we prove that this theory has the same divergences as ordinary Yang Mills theory in the Landau gauge and that it is unitary. The restriction of the functional integral is interpreted as a kind of sponta

H. M. Babujian, R. Flume

We generalize the previously established connection between the off-shell Bethe ansatz equation for inhomogeneous SU(2) lattice vertex models in the quasiclassical limit and the solutions of the SU(2) Knizhnik-Zamolodchikov equations to the case of arbitrary simple Lie algebras.

Salvatore De Martino, Silvio De Siena, Fabrizio Illuminati, Giuseppe Vitiello

We show that uncertainty relations, as well as minimum uncertainty coherent and squeezed states, are structural properties for diffusion processes. Through Nelson stochastic quantization we derive the stochastic image of the quantum mechanical coherent and squeezed states.

Hitoshi Konno

Using free field representation of quantum affine algebra $U_q(\widehat{sl_2})$, we investigate the structure of the Fock modules over $U_q(\widehat{sl_2})$. The analisys is based on a $q$-analog of the BRST formalism given by Bernard and Felder in the affine Kac-Moody algebra $\widehat {sl_2}$. We give an explicit construction of the singular vectors using

R. Parthasarathy, K. S. Viswanathan

The immersion of the string world sheet, regarded as a Riemann surface, in $R^3$ and $R^4$ is described by the generalized Gauss map. When the Gauss map is harmonic or equivalently for surfaces of constant mean curvature, we obtain Hitchin&#39;s self-dual equations, by using $SO(3)$ and $SO(4)$ gauge fields constructed in our earlier studies. This complement

A. I. Davydychev

Problems occurring in physically important non-trivial examples of loop calculations are discussed. A procedure of deriving expansions of two-loop self-energy diagrams with different masses is constructed. The cases of small and large external momentum are considered. The coefficients of the expansions are calculated analytically. Comparison with numerical r

A. Kusenko, R. Shrock

We construct new invariants and give several theorems which determine in general (i) the number of physically meaningful phases in quark mass matrices and (ii) which elements of these matrices can be rendered real by rephasings. We illustrate our results with simple models.

S. D. Bass, A. W. Thomas

We provide an introduction to the ideas of spin-dependent deep-inelastic scattering. Recent experimental results are summarised and possible explanations related to the axial anomaly presented. Further experiments that could greatly clarify the situation are also described.

Marc Sher

Very little is known about the mass spectrum of fermions in the standard model. In this talk, I point out that in the simplest extension of the standard model, in which all right-handed fields are singlets, it is quite possible that a fourth-generation neutrino will be heavier that its charged counterpart. The latter will then be very long-lived. Three plaus

T. Altherr, E. Petitgirard, T. del Rio Gaztelurrutia

Using thermal field theory methods, we recalculate axion emission from dense plasmas. We study in particular the Primakoff and the bremsstrahlung processes. The Primakoff rate is significantly suppressed at high densities, when the electrons become relativistic. However, the bound on the axion-photon coupling, $G<10^{-10}$ GeV, is unaffected, as it is constr

K. Langfeld

The effective potential for the order parameter $ϕ^{\dagger } ϕ$ is investigated in massless $ϕ^{4}$-theory in the presence of magnetic fields at finite temperature. It is found that the first order nature of the phase transition from the non-trivial to the perturbative ground state at a critical temperature is unchanged by the presence of magnetic fields, t

Mikhail Bilenky, Arcadi Santamaria

We study several problems related to the construction and the use of effective Lagrangians by considering an extension of the standard model that includes a heavy scalar singlet coupled to the leptonic doublet. Starting from the full renormalizable model, we build an effective field theory by integrating out the heavy scalar. A local effective Lagrangian (up

I. Jack, D. R. T. Jones, K. L. Roberts

It is shown that regularisation by dimensional reduction is a viable alternative to dimensional regularisation in non-supersymmetric theories.

Mannque Rho

This article is based on a series of lectures given at ELAF 93 on the description of low-energy hadronic systems {\it in and out} of hadronic medium. The focus is put on identifying, with the help of a Cheshire Cat philosophy, the effective degrees of freedom relevant for the strong interactions from a certain number of generic symmetry properties of QCD. Th

J. R. Cudell, B. U. Nguyen

We calculate the order alpha_s^2 and order alpha_s^3 QCD contributions to colour-singlet exchange in the leading log s approximation. We implement the resulting amplitude at the hadronic level and thus construct the QCD pomeron and odderon to this order of perturbation theory. We show that the structure of the hadronic form factors provides a natural mechani

P. Altevogt, A. Linke

We describe an algorithm for dynamic load balancing of geometrically parallelized synchronous Monte Carlo simulations of physical models. This algorithm is designed for a (heterogeneous) multiprocessor system of the MIMD type with distributed memory. The algorithm is based on a dynamic partitioning of the domain of the algorithm, taking into account the actu

Weonjong Lee

The QCD light quark mass renormalized at a 1 GeV scale in the $ \overline{MS} $ scheme is obtained from the numerical results of the lattice QCD simulation with staggered fermions. The primary emphasis is given to the connection between the lattice and continuum parameters. The results are compared with those from the QCD sum rule.

A. Houghton, H. -J. Kwon, J. B. Marston

We study the stability and single-particle properties of Fermi liquids in spatial dimensions greater than one via bosonization. For smooth non-singular Fermi liquid interactions we obtain Shankar&#39;s renormalization- group flows and reproduce well known results for quasi-particle lifetimes. We demonstrate by explicit calculation that spin-charge separation

Jose Riera, Elbio Dagotto

A multiband CuO Hubbard model is studied which incorporates long-range (LR) repulsive Coulomb interactions. In the atomic limit, it is shown that a charge-transfer from copper to oxygen ions occurs as the strength of the LR interaction is increased. The regime of phase separation becomes unstable, and is replaced by a uniform state with doubly occupied oxyge

Sabino Matarrese, Ornella Pantano, Diego Saez

The non--linear dynamics of cosmological perturbations of an irrotational collisionless fluid is analyzed within General Relativity. Relativistic and Newtonian solutions are compared, stressing the different role of boundary conditions in the two theories. Cosmological implications of relativistic effects, already present at second order in perturbation theo

J. Law, Avinash Khare, R. K. Bhaduri, Akira Suzuki

For three anyons confined in a harmonic oscillator, only the class of states that interpolate nonlinearly with the statistical parameter contributes to the third virial coefficient of a free anyon gas. Rather than evaluating the full three-body partition function as was done in an earlier publication (Phys. Rev. {\bf A46}, 4693 (1992)), here only the nonline

Pijush K. Ghosh

We consider a generalization of the abelian Higgs model with a Chern-Simons term by modifying two terms of the usual Lagrangian. We multiply a dielectric function with the Maxwell kinetic energy term and incorporate nonminimal interaction by considering generalized covariant derivative. We show that for a particular choice of the dielectric function this mod

Hitoshi Murayama, T. Yanagida

We show that the leptogenesis is automatic within the supersymmetric standard model if there exist right-handed neutrinos with mass less than $H_{\it inf}$, the expansion rate during the inflation. Its scalar component grows during the inflation due to the quantum fluctuation, oscillates coherently after the inflation, and its decay generates lepton asymmetr

J. L. Goity

The relaxation times of particle numbers in hot hadronic matter with vanishing baryon number are estimated using the ideal gas approximation and taking into account resonance decays and annihilation processes as the only sources of particle number fluctuations. Near the QCD critical temperature the longest relaxation times turn out to be of the order of 10 f

Jukka Maalampi

We discuss various experimental tests of the left-right symmetric model possible to perform in the next generation linear colliders. We consider processes which provide sensitive probes of the basic ingredients of the model: right-handed gauge bosons, right-handed Majorana neutrinos, lepton number violating interactions and triplet Higgs scalars. A supersymm

S. B. Giddings

The information loss and remnant proposals for resolving the black hole information paradox are reconsidered. It is argued that in typical cases information loss implies energy loss, and thus can be thought of in terms of coupling to a spectrum of ``fictitious&#39;&#39; remnants. This suggests proposals for information loss that do not imply planckian energy

Daniel E. Cohen

Let $Γ$ be a finite graph, and for each vertex $i$ let $G_i$ be a finitely presented group. Let $G$ be the graph product of the $G_i$. That is, $G$ is the group obtained from the free product of the $G_i$ by factoring out by the smallest normal subgroup containing all $[g,h]$ where $g\in G_i$ and $h\in G_j$ and there is an edge joining i and j . We show that

Daniel E. Cohen

Let $Γ$ be a finite graph together with a group $G_v$ at each vertex $v$. The graph product $G(Γ)$ is obtained from the free product of all $G_v$ by factoring out by the normal subgroup generated by $\{g^{-1}h^{-1}gh; g\in G_v, h\in G_w\}$ for all adjacent $v,w$. In this note we construct a projective resolution for $G(Γ)$ given projective resolutions for ea

Stephen G. Naculich, Harold A. Riggs, Howard J. Schnitzer

We show that the string representation of the QCD$_2$ partition function satisfies, by virtue of a Young-tableau-transposition symmetry, the topological constraint that any branched covering of an orientable or nonorientable surface without boundary must have an {\em even} branch point multiplicity. This statement holds for each chiral sector and requires mu

Avinash Khare, Rajat K. Bhaduri

Using the ideas of supersymmetry and shape invariance we show that the eigenvalues and eigenfunctions of a wide class of noncentral potentials can be obtained in a closed form by the operator method. This generalization considerably extends the list of exactly solvable potentials for which the solution can be obtained algebraically in a simple and elegant ma

Avinash Khare, Rajat K. Bhaduri

The three-body problem in one-dimension with a repulsive inverse square potential between every pair was solved by Calogero. Here, the known results of supersymmetric quantum mechanics are used to propose a number of new three-body potentials which can be solved algebraically. Analytic expressions for the eigenspectrum and the eigenfunctions are given with a