November 1994 arXiv papers — page 3

Don N. Page

In 1976 Stephen Hawking proposed that information may be lost from our universe as a pure quantum state collapses gravitationally into a black hole, which then evaporates completely into a mixed state of thermal radiation. Although this proposal is controversial, it is tempting to consider analogous processes that might occur in certain theories of conscious

A. Yu. Umnikov, F. C. Khanna, L. P. Kaptari

The off-mass-shell behavior of the nucleon structure function, $F_2^N$, is studied within an approach motivated by the Sullivan model. Deep inelastic scattering on the nucleon is considered in the second order in the pion-nucleon coupling constant, corresponding to the dressing of the bare nucleons by the mesonic cloud. The inclusive and semi-inclusive deep

Jonathan L. Rosner

A brief overview is presented of the standard model of electroweak interactions, including precision tests, the role of the Cabibbo-Kobayashi-Maskawa (CKM) matrix in describing CP violation, windows on intermediate-scale physics, and the nature of the Higgs phenomenon.

C. Wieczerkowski, Y. Xylander

We propose a method using perturbation theory in the running coupling constant and the idea of scaling to determine improved actions for lattice field theories combining Wilson's renormalization group with Symanzik's improvement program . The method is based on the analysis of a single renormalization group transformation. We test it on the hierarchi

J. S. F. Chan, R. B. Mann

We show that the interior of a charged, spinning black hole formed from a general axially symmetric gravitational collapse is unstable to inflation of both its mass and angular momentum parameters. Although our results are formulated in the context of $(2+1)$-dimensional black holes, we argue that they are applicable to $(3+1)$ dimensions.

Jeroen Snippe, Pierre van Baal

We construct all instantons in the \nlsig\ on a cylindrical space-time, known not to exist on a finite time interval. The scale parameter, $ρ$, is related to the boundary condition in time. This may cure the $ρ\rightarrow0$ divergent instanton gas, through a proper inclusion of in and out states in the path integral.

Ashoke Sen

We construct the general electrically charged, rotating black hole solution in the heterotic string theory compactified on a six dimensional torus and study its classical properties. This black hole is characterized by its mass, angular momentum, and a 28 dimensional electric charge vector. We recover the axion-dilaton black holes and Kaluza-Klein black hole

Robert Carroll

For certain situations we give a geometrical background for quasiclassical KP calculations based on an explicit connection to quantum mechanics and the collapse of coherent states to coadjoint orbits for classical operators.

Oleg A. Soloviev

It is shown that the space of cohomology classes of the $SU(1,1)/U(1)$ coset at negative level $k$ contains states of relevant conformal dimensions. These states correspond to the energy density operator of the associated nonlinear sigma model. We exhibit that there exists a subclass of relevant operators forming a closed fusion algebra. We make use of these

Hans-Peter Thienel

This work proposes a natural extension of the Bargmann-Fock representation to a SUSY system. The main objective is to show that all essential structures of the n-dimensional SUSY oscillator are supplied by basic differential geometrical notions on an analytical R^n, except for the scalar product which is the only additional ingredient. The restriction to rea

R. W. Gebert, H. Nicolai

We present a nontechnical introduction to the hyperbolic Kac Moody algebra E_{10} and summarize our recent attempt to understand the root spaces of Kac Moody algebras of hyperbolic type in terms of a DDF construction appropriate to a subcritical compactified bosonic string.

Ph. Brax, U. Ellwanger, C. A. Savoy

The particle spectrum of the supersymmetric extension of the standard model with a gauge singlet is studied. Soft supersymmetry breaking terms are explicitly chosen to be non-universal according to orbifold string theory. they depend on modular weights of chiral fields and on an angle $θ$ specifying the supersymmetry breaking sector. Imposing radiative weak

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

The polarization dependent momentum distributions of top quarks and their decay products are calculated for $t\bar t$ production at future $e^+e^-$ colliders with polarized beams. The Green function formalism is applied to this reaction near energy threshold. The Lippmann--Schwinger equations for the $S$-wave and $P$-wave Green functions are solved numerical

Jens Erler

We investigate the effects of possible new four-Fermi operators on $e^+$ $e^-$ annihilation experiments. They represent a class of new physics, which has the potential to change the parameters of the $Z$ boson and at the same time interferes with their determination from the data. We show that in the presence of such operators the $Z$ parameters obtained fro

G. Nardulli

I review recent developments in the description of the interactions between light and heavy mesons by an effective chiral lagrangian having the symmetries of the Heavy Quark Effective Theory. In particular the problem of the determination of the strong coupling constants $g_{P^* P π}$ and $g_{P^* P ρ}$ ($P, P^*=$ heavy mesons) is addressed. Invited talk give

J. K. Mizukoshi, O. J. P. Eboli, M. C. Gonzalez-Garcia

We analyse the constraints on scalar leptoquarks coming from radiative corrections to $Z$ physics. We perform a global fitting to the LEP data including the contributions of the most general effective Lagrangian for scalar leptoquarks, which exhibits the $SU(2)_L \times U(1)_Y$ gauge invariance. We show that the bounds on leptoquarks that couple to the top q

Joon Ha Kim, Sooman Yee, Hyun Kyu Lee

We study the characteristics of the QCD phase transitions in dense hadronic matter using the Skyrme model constructed on S^3. We find numerically the localized solutions on $S^3$ using the extended Skyrme model which implements correctly the scale symmetry of QCD. The transition from the localized phase to the delocalized phase is found to be of first order

K. M. Bitar, R. G. Edwards, U. M. Heller, A. D. Kennedy

We present data for the scaling behavior of lattice QCD with two flavors of light Wilson fermions. This is done by matching $π$ n and $ρ$ masses at the two lattice sizes of $16^3\times32 $ and $8^3\times16$. We find that at $β=6/g^2\equiv5.3$ the matching does not occur over a range extending down to $β=3.5$. For $β=5.5$ matching may be achieved at $β=4.8-4.

L. A. Fernandez, A. Munoz Sudupe, J. J. Ruiz-Lorenzo, A. Tarancon

We propose a family of renormalization group transformations characterized by free parameters that may be tuned in order to reduce the truncation effects. As a check we test them in the three dimensional XY model. The Schwinger--Dyson equations are used to study the renormalization group flow.

Martin Baker

The Iteratively Smoothing Unigrid algorithm (ISU), a new multigrid method for computing propagators in Lattice Gauge Theory, is explained. The main idea is to compute good (i.e.\ smooth) interpolation operators in an iterative way. This method shows {\em no critical slowing down} for the 2-dimensional Laplace equation in an SU(2) gauge field. First results f

Tim R. Morris

By writing the flow equations for the continuum Legendre effective action (a.k.a. Helmholtz free energy) with respect to a particular form of smooth cutoff, and performing a derivative expansion up to some maximum order, a set of differential equations are obtained which at FPs (Fixed Points) reduce to non-linear eigenvalue equations for the anomalous scalin

F. Csikor, Z. Fodor, J. Hein, K. Jansen

We present results obtained from a numerical investigation of the electroweak phase transition in the SU(2)-Higgs model. The simulations are performed at two values of the Higgs boson mass, $M_H\approx 20$ GeV and $M_H\approx 50$ GeV. While the phase transition is of strongly first order at the smaller value of the Higgs mass it weakens rapidly when the Higg

Marcus Kriele, Jerome Martin

There exists a widespread belief that signature type change could be used to avoid spacetime singularities. We show that signature change cannot be utilised to this end unless the Einstein equation is abandoned at the suface of signature type change. We also discuss how to solve the initial value problem and show to which extent smooth and discontinuous sign

J. M. Lopez, M. A. Rodriguez, L. Pesquera

We investigate self-averaging properties in the transport of particles through random media. We show rigorously that in the subdiffusive anomalous regime transport coefficients are not self--averaging quantities. These quantities are exactly calculated in the case of directed random walks. In the case of general symmetric random walks a perturbative analysis

Yu. S. Barash, A. V. Galaktionov, A. D. Zaikin

We develop a microscopic analysis of superconducting and dissipative currents in junctions between superconductors with d-wave symmetry of the order parameter. We study the proximity effect in such superconductors and show that for certain crystal orientations the superconducting order parameter can be essentially suppressed in the vicinity of a nontranspare

Stephen M. Cox, A. J. Roberts

The long-time behaviour of many dynamical systems may be effectively predicted by a low-dimensional model that describes the evolution of a reduced set of variables. We consider the question of how to equip such a low-dimensional model with appropriate initial conditions, so that it faithfully reproduces the long-term behaviour of the original high-dimension

David Roberts, Andrew R Liddle, David H Lyth

We consider a variant of Hybrid Inflation, where inflation is driven by two interacting scalar fields, one of which has a `Mexican hat' potential and the other a quartic potential. Given the appropriate initial conditions one of the fields can be trapped in a false vacuum state, supported by couplings to the other field. The energy of this vacuum can be

Richard S Ellis

I review two observational programs which, together, promise to unravel the detailed astrophysical evolution of normal field galaxies over the last 5-7 Gyr. Systematic ground-based spectroscopy of faint galaxies have revealed an increasing faint end slope for the luminosity function with redshift. The trend is strongest for galaxies undergoing intense star-f

C. Carlson, T. Goldman, J. Perez-Mercader

We propose that the dynamic Casimir effect is a mechanism that converts the energy of neutron starquakes into $γ$--rays. This mechanism efficiently produces photons from electromagnetic Casimir energy released by the rapid motion of a dielectric medium into a vacuum. Estimates based on the cutoff energy of the gamma ray bursts and the volume involved in a st

G. D'Ambrosio, G. Isidori, A. Pugliese

Starting from the time evolution of the C-odd $\bar{K}^0 K^0$ system, we analyze the asymmetries measurable at DAFNE and their implications on CP violation and on the possible tests of T and CPT symmetries. In particular the ratio $ε'/ε$ can be measured with high precision (up to about $10^{-4}$ for the real part). The CP-, T- and CPT-violating parameter

Dan Abramovich

We refine a result of L. Caporaso, J. Harris and B. Mazur, and prove: Supposons que la conjecture de Lang soit vraie. Soit $K$ un corps des nombres et $g>1$ un entier. Il existe un nombre $N(K,g)$ tel que si $L$ est une extension de degré $\leq 3$ de $K$ et $C$ est une courbe lisse projective connèxe, de genre $g$ définie sur $L$ on a $$\# C(L) < N(K,g). $$

B. M. Zupnik

We discuss the gauge theory for quantum group $SU_q (2)\times U(1) $ on the quantum Euclidean space. This theory contains three physical gauge fields and one$\; U(1)-$gauge field with a zero field strength. We construct the quantum-group self-duality equation (QGSDE) in terms of differential forms and with the help of the field-strength decomposition. A defo

Michael Frank, Vladimir M. Manuilov

For W*-algebras A and self-dual Hilbert A-modules M we show that every self-adjoint, &#39;&#39;compact&#39;&#39; module operator on M is diagonalizable. Some specific properties of the eigenvalues and of the eigenvectors are described.

Bryan Webber

Hadronization corrections to the predictions of perturbative QCD are reviewed. The existing models for the conversion of quarks and gluons into hadrons are summarized. The most successful models give a good description of the data on $e^+e^-$ event shapes and jet fragmentation functions, and suggest that the dominant hadronization effects have a $1/Q$ depend

J. A. Gomez Tejedor, M. J. Vicente-Vacas, E. Oset

The inclusive A(gamma,pi+ pi-)X reaction is studied theoretically. A sizeable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section (sigma_deuteron * A/2). This enhancement is due to the modifications in the nuclear medium of the gamma N ----> pi pi N amplitude and the pion dispersion relation. The enhancemen

B. Ricci, S. Degl&#39;Innocenti, G. Fiorentini

We quantitatively determine the effect and the uncertainty on solar neutrino production arising from the screening process. We present predictions for the solar neutrino fluxes and signals obtained with different screening models available in the literature and by using our stellar evolution code. We explain these numerical results in terms of simple laws re

John H. Schwarz

String theory appears to admit a group of discrete field transformations -- called $S$ dualities -- as exact non-perturbative quantum symmetries. Mathematically, they are rather analogous to the better-known $T$ duality symmetries, which hold perturbatively. In this talk the evidence for $S$ duality is reviewed and some speculations are presented.

Claudio Coriano&#39;, Alan R. White

The scale-invariant $O(g^4)$ Lipatov kernel has been determined by t-channel unitarity. The forward kernel responsible for parton evolution is evaluated and its eigenvalue spectrum determined. In addition to a logarithmic modification of the $O(g^2)$ kernel a distinct new kinematic component appears. This component is infra-red finite without regularization

R. Ya. Kezerashvili

We present the effective Hamiltonian for an electron-nucleus interaction in non-relativistic limit up to the second order in the inverse nucleon mass. This Hamiltonian takes into account the distortion of electron waves and allows to calculate its effect as well as matrix elements for off-shell transitions in $(e,e&#39;p)$ reactions.

Y. Ohbayasi, Y. Suzuki

The $β$-decay of $^{11}$Li into $^9$Li and {\it d} is studied using simple halo wave functions of $^{11}$Li. The sensitivity of the transition probability is elucidated on a description of the halo part and on a choice of the potential between $^9$Li and {\it d} .

Beatriz Gato-Rivera, Jose Ignacio Rosado

A conformal field theory can be recovered, via the Kontsevich-Miwa transform, as a solution to the Virasoro constraints on the KP tau function. That theory, which we call KM CFT, consists of d \leq 1 matter plus a scalar and a dressing prescription: Δ= 0 for every primary field. By adding a spin-1 bc system the KM CFT provides a realization of the N=2 twiste

Ettore Aldrovandi, Gregorio Falqui

We discuss geometrical aspects of Toda Fields generalizing the links between Liouville gravity and uniformization of Riemann surfaces of genus greater than one. The framework is the interplay between the hermitian and the holomorphic geometry of vector bundles on such Riemann surfaces. Pointing out how Toda fields can be considered as equivalent to Higgs sys

M. Billo&#39;, P. Fré

We consider certain N=4 supersymmetric gauge theories in D=2 coupled to quaternionic matter multiplets in a minimal way. These theories admit as effective theories sigma-models on non-trivial HyperKähler manifolds obtained as HyperKähler quotients. The example of ALE manifolds is discussed. (Based on a talk given by P. Fré at the F. Gursey Memorial Conferenc

S. A. Frolov, A. A. Slavnov, C. Sochichiu

Canonical quantization of the Wess-Zumino (WZ) model including chiral interaction with gauge field is considered for the case of a degenerate action. The two-dimensional SU(2) Yang-Mills model and the four-dimensional SU(3) chiral gauge model proposed in the paper \cite{fss} are studied in details. Gauge invariance of the quantum theory is established at the

V. Tarasov, A. Varchenko

We give an integral representation for solutions to the quantized Knizhnik- Zamolodchikov equation (qKZ) associated with the Lie algebra $gl_{N+1}$. Asymptotic solutions to qKZ are constructed. The leading term of an asymptotic solution is the Bethe vector -- an eigenvector of the transfer-matrix of a quantum spin chain model. We show that the norm of the Be

E. C. Marino

A new local and gauge invariant quantum vortex operator is constructed in three-dimensional gauge field theories. The correlation functions of this operator are evaluated exactly in pure Maxwell theory and by means of a loop expansion in the Abelian Higgs model. In the broken symmetry phase of the latter an explicit expression for the mass of the quantum vor

Varun Sheel, Hiranmaya Mishra, Jitendra C. Parikh

Equal time, point to point correlation functions for spatially separated meson currents are calculated with respect to a variational construct for the ground state of QCD. With exact calculations, vector, axial vector and scalar channels show qualitative agreement with the phenomenological predictions, where as pseudoscalar channel does not. However, the pse

R. Foot, H. Lew

A novel gauge model which has a spontaneously broken parity symmetry is constructed. The model has only 2 parameters beyond those of the standard model. Some of the unusual implications of the model are discussed.

Seiji Matsumoto

A global analysis is performed using the latest data from LEP and SLC. Constraints on the electroweak universal parameters ($S,T,U$) and on the masses of the top quark and Higgs boson within the Standard Model (SM) are investigated. The uncertainties due to the QCD and QED effective couplings, $α_s(\mz)$ and $\barα(\mmz)$, are examined in detail. Even though

G. Dvali, Z. Tavartkiladze, J. Nanobashvili

We reconsider a cosmological evolution of domain walls produced by spontaneous breaking of an approxime discrete symmetry. We show, that domain walls may never collapse even if the standard bound on the vacuum energy asymmetry is satisfied. Instead of disappearing, these defects may form stable ``bound states&#39;&#39; - double wall systems. Possible stabili

A. Djouadi, B. Lampe, P. M. Zerwas

The measurement of the forward-backward asymmetries of heavy quarks provides one of the most precise determinations of $\sin^2θ_W$ in $Z$ decays. We discuss in detail the one--loop QCD radiative corrections to these asymmetries. Results are given for single heavy--quark jet asymmetries and asymmetries of the thrust axis, as well as for heavy--quark two--jet

Michael Gronau

We review the subject of CP violation in the $B$ meson system within the Standard Model of CP violation, which is based on a complex phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Three kinds of CP nonconservation are studied: In $B^0-\Bbar$ mixing, in mixed neutral $B$ decays to states which are common decay products of $B^0$ and $\Bbar$ and in direct

Martin Schmaltz

I discuss a SUSY-GUT model with a non-Abelian discrete family symmetry that explains the observed hierarchical pattern of quark and lepton masses. This $SO(10) \times Δ(75)$ model predicts modified quadratic seesaw neutrino masses and mixing angles which are interesting for three reasons: i.) they offer a solution to the solar neutrino problem, ii.) the tau

Nigel Goldenfeld

A brief outline is given of the description of phase transition kinetics in condensed matter systems with a continuous symmetry, emphasising the roles of dissipation, coarse-graining and scaling. The possible relevance of these ideas to the early universe is explored in the contexts of the GUT string transition and the electroweak transition.

M-P Lombardo, A. Kocic, J. B. Kogut

We study the critical region of lattice QED4 in the quenched approximation. The issue of triviality is addressed by contrasting simulation results for $<\barψψ>$ and for the susceptibilities with the predictions of two critical scenarios -- powerlaw scaling, and triviality à la Nambu--Jona Lasinio. We discriminate among the two possibilities with reasonable

Margarita Garcia Perez, Pierre van Baal

The cooling algorithm for saddle points presented in ref. [1] is generalized to obtain static classical solutions of the SU(2)-Higgs field theory in the limit of infinite Higgs self-coupling. The sphaleron energy obtained via this algorithm is ${\cal E}_{\rm sph}= 5.08(7)\,M_W/α_W$ to be compared with 5.0707 obtained in the variational approach [2].

Simon Hands

Strongly coupled QED is a model whose physics is dominated by short-ranged effects. In order to assess which features of numerical simulations of the chiral phase transition are universal and which are not, we have formulated a quenched version of the model in which photon degrees of freedom are defined on a lattice of spacing a, but fermions only on a latti

Paolo Cea, Leonardo Cosmai

We study the distribution of the color fields due to a static quark-antiquark pair in SU(2) lattice gauge theory. We find evidence of dual Meissner effect. We put out a simple relation between the penetration length and the string tension.

Pierre van Baal

Laplacian gauge fixing was introduced to find a unique representative of the gauge orbit, which on the lattice could be implemented by a ``finite&#39;&#39; algorithm. What was still lacking was a perturbative formulation of this gauge, which will be presented here. However, renormalizability is still to be demonstrated. For torodial and spherical geometries

Bas van den Heuvel, Pierre van Baal

For SU(2) gauge theory on the three-sphere we focus on a subspace of modes of the gauge field that contains the tunnelling paths and the sphalerons and on which the energy functional is degenerate to second order in the fields. The ultimate goal is to study the $θ$-dependence of the low-lying states for this model by imposing boundary conditions on the funda

Dmitri V. Vassilevich

We suggest a method of reduction of mixed absolute and relative boundary conditions to pure ones. The case of rank two tensor is studied in detail. For four-dimensional disk the corresponding heat kernel is expressed in terms of scalar heat kernels. The result for scaling behavior $ζ(0)$ agrees with previous calculations.

Sujan K. Dhar, Rahul Pandit, Sriram Ramaswamy

We construct a driven sandpile slope model and study it by numerical simulations in one dimension. The model is specified by a threshold slope $σ_c\/$, a parameter $α\/$, governing the local current-slope relation (beyond threshold), and $j_{\rm in}$, the mean input current of sand. A nonequilibrium phase diagram is obtained in the $α\, -\, j_{\rm in}\/$ pla

E. Alfinito, G. Profilo, G. Soliani

We analyze two extended versions [the Ishimori model (IM) and a related system, which will be called modified Ishimori model (mIM)] of the continuous Heisenberg model in (2+1)-dimensions within the complex Hirota scheme. The IM, proposed in 1984, is an integrable (2+1)-dimensional topological spin field model which has been studied in many theoretical framew

Igor V. Lerner

It is shown that the characteristics of the mesoscopic fluctuations in the conventional quantum-diffusion model and the model of the non-coherent (`classical&#39;) diffusion in media with long-range correlated disorder are quite similar in the weak-disorder limit. The relative values of the variance and of the high-order moments of the fluctuations in one mo

Igor V. Lerner, Yoseph Imry

Using the conventional scaling approach as well as the renormalization group analysis in $d=2+ε$ dimensions, we calculate the localization length $ξ(B)$ in the presence of a magnetic field $B$. For the quasi 1D case the results are consistent with a universal increase of $ξ(B)$ by a numerical factor when the magnetic field is in the range $\ell\ll{\ell_{\!{_

Tetsuya Hattori, Hideo Nakajima

Some problems related to the transition density u(t,x) of the diffusion on the Sierpinski gasket are considerd, based on recent rigorous results and detailed numerical calculations. The main contents are an extension of Flory&#39;s formula for the end-to-end distance exponent of self-avoiding walks on the fractal spaces, and an evidence of the oscillatory be

V. S L&#39;vov, V. V Lebedev

We show that the Kolmogorov-1941 picture of fully developed hydrodynamic turbulence (with the scaling of the structure functions $S_n(R) \propto R^{n/3}$) necessarily leads to an anomalous scaling for correlation functions which include the rate of energy dissipation $\varepsilon (t,{\bf r})$, these correlation functions being described by an independent ind

C. Xu, V. Buat

We compare the ultra-violet, optical, and far-infrared emission for a sample of 135 spiral galaxies in order to address the widely debated problem concerning the opacity of spiral disks. We find that the re-radiation of the dust, estimated from the far-infrared emission, is on average only 31$\pm 1$ percent of the bolometric luminosity of a spiral galaxy, in

Heino Falcke, Matthew A. Malkan, Peter L. Biermann

We investigate the correlation between the accretion disk (UV) luminosity and the radio core emission of a quasar sample. In a radio/$L_{\rm disk}$ plot we find the quasars to be separated into four classes: core dominated quasars (CDQ), lobe dominated quasars (LDQ), radio-intermediate quasars (RIQ) and radio weak quasars. In general the radio core emission

Riccardo Capovilla, Jemal Guven

A coupled system of non-linear partial differential equations is presented which describes non-perturbatively the evolution of deformations of a relativistic membrane of arbitrary dimension, $D$, in an arbitrary background spacetime. These equations can be considered from a formal point of view as higher dimensional analogs of the Raychaudhuri equations for

Riccardo Capovilla, Jemal Guven

A kinematical description of infinitesimal deformations of the worldsheet spanned in spacetime by a relativistic membrane is presented. This provides a framework for obtaining both the classical equations of motion and the equations describing infinitesimal deformations about solutions of these equations when the action describing the dynamics of this membra

A. D. Martin, D. Zeppenfeld

We critically examine the evaluation of the hadronic contribution to the running of the QED coupling, $\alpha$, from $Q^2=0$ to $Q^2=M_Z^2$. Using data for $e^+e^-\to{}$hadrons we find that $\alpha(M_Z^2)^{-1} = 128.99\pm 0.06$, as compared to the existing value of $128.87\pm 0.12$.

Gustav W. Delius, Marc Grisaru

We compute quantum corrections to soliton masses in affine Toda theories with imaginary exponentials based on the nonsimply-laced Lie algebras $c_n^{(1)}$. We find that the soliton mass ratios renormalize nontrivially, in the same manner as those of the fundamental particles of the theories with real exponentials based on the nonsimply-laced algebras $b_n^{(

Z. K. Silagadze

Some atomic decays of elementary particles with pionium ($π^+π^-$-dimesoatom) in the final state are considered. Only for K-meson atomic decays are the corresponding branching ratios big enough to make their experimental study realistic. The $O(α)$ order corrections to the lifetime of pionium are also calculated.

Z. K. Silagadze

A possible connection between the existence of three quark-lepton generations and the triality property of SO(8) group (the equality between 8-dimensional vectors and spinors) is investigated.

Jaume Garriga, Tanmay Vachaspati

We study linked loops of string in the presence of bosonic condensates and fermionic zero modes on the strings. We find that the strings necessarily carry a current if the bosons have an Aharanov-Bohm interaction with the string. The fermionic case is analyzed in the context of the standard model where there are lepton and quark zero modes on $Z-$strings. He

S. M. Bilenky, C. Giunti

In the first part of this report we present the results of a model independent analysis of the existing solar neutrino data. We obtained forbidden regions in the plane of the parameters Delta m^2 and sin^2 2 theta in two cases: A) Without any restrictions on the values of the solar neutrino fluxes from different reactions; B) With some restrictions that take

Thorsten Feldmann, Thomas Mannel

Assuming that the chiral symmetry of the light degrees of freedom is realized as the vector symmetry proposed by Georgi, we write down a chiral Lagrangian for heavy mesons which incorporates both heavy quark and vector symmetry. Some of the phenomenological implications of this idea are considered.

N. J. MacKay, G. M. T. Watts

We calculate the first quantum corrections to the masses of solitons in imaginary-coupling affine Toda theories using the semi-classical method of Dashen, Hasslacher and Neveu. The theories divide naturally into those based on the simply-laced, the twisted and the untwisted non-simply-laced algebras. We find that the classical relationships between soliton a

S. Bellucci, S. Krivonos, A. Sorin

It has recently been shown that the $W_3$ and $W_3^{(2)}$ algebras can be considered as subalgebras in some linear conformal algebras. In this paper we show that the nonlinear algebras $W_{2,4}$ and $WB_2$ as well as Zamolodchikov&#39;s spin $5/2$ superalgebra also can be embedded as subalgebras into some linear conformal algebras with a finite set of curren

C. Coriano&#39;, A. R. White

The Lipatov equation can regarded as a reggeon Bethe-Salpeter equation in which higher-order reggeon interactions give higher-order kernels. Infra-red singular contributions in a general kernel are produced by t-channel nonsense states and the allowed kinematic forms are determined by unitarity. Ward identity and infra-red finiteness gauge invariance constra

Saurabh D. Rindani

The prospects of experimental detection of $CP$ violation at $e^+e^-$ and $pp/p\overline{p}$ colliders are reviewed. After a general discussion on the quantities which can measure $CP$ violation and on the implications of the $CPT$ theorem, various possibilities of measuring $CP$ violation arising outside the standard model are taken up. $CP$ violation in le

B. F. Gibson, I. R. Afnan, J. A. Carlson, D. R. Lehman

The $ΛN - ΣN$ coupling in $Λ$--hypernuclei and $ΛΛ- ΞN$ coupling in $ΛΛ$--hypernuclei produce novel physics not observed in the conventional, nonstrange sector. Effects of $Λ\leftrightarrow Σ$ conversion in $^3_Λ$H are reviewed. The role of $ΛN - ΣN$ coupling suppression in the $A=4,5$ $Λ$--hypernuclei due to Pauli blocking is highlighted, and the implicatio

K. Holinde

The present status of the chiral approach to the $NN$ interaction as proposed by Weinberg is discussed. The important role of correlation effects and explicit vector meson ($ρ$, $ω$) exchange in the dynamics of baryon-baryon interactions is demonstrated. As an example, the inclusion of the exchange of a correlated pair of $π$ and $ρ$ meson between two nucleo

A. Hombach, A. Engel, S. Teis, U. Mosel

We calculate the quasifree photoproduction of pions and eta mesons on nuclei from 12C to 208Pb. Assuming that for the quasifree process the cross sections for pi/eta - photoproduction on a nucleon in medium are -- besides a lowering due to Pauli blocking -- identical to those on a free nucleon, we use these as an input. The produced mesons or resonances then

D. Fliegner, P. Haberl, M. G. Schmidt, C. Schubert

The one--loop effective action for the case of a massive scalar loop in the background of both a scalar potential and an abelian or non--abelian gauge field is written in a one--dimensional path integral representation. From this the inverse mass expansion is obtained by Wick contractions using a suitable Green function, which allows the computation of highe

Davide Stelitano

The Aharonov-Bohm scattering of a localized wave packet is considered. A careful analysis of the forward direction points out new results: according to the time-dependent solution obtained by means of the asymptotic representation for the propagator (kernel), a phenomenon of auto-interference occurs along the forward direction, where, also, the probability d

N. P. Landsman, U. A. Wiedemann

The connection between space-time covariant representations (obtained by inducing from the Lorentz group) and irreducible unitary representations (induced from Wigner&#39;s little group) of the Poincaré group is re-examined in the massless case. In the situation relevant to physics, it is found that these are related by Marsden-Weinstein reduction with respe

N. P. Landsman

We attempt to clarify the main conceptual issues in approaches to `objectification&#39; or `measurement&#39; in quantum mechanics which are based on superselection rules. Such approaches venture to derive the emergence of classical `reality&#39; relative to a class of observers; those believing that the classical world exists intrinsically and absolutely are

N. P. Landsman

These notes present an introduction to an analytic version of deformation quantization. The central point is to study algebras of physical observables and their irreducible representations. In classical mechanics one deals with real Poisson algebras, whereas in quantum mechanics the observables have the structure of a real non-associative Jordan-Lie algebra.

N. P. Landsman

The irreducible unitary representations of the Banach Lie group $U_0(\H)$ (which is the norm-closure of the inductive limit $\cup_k U(k)$) of unitary operators on a separable Hilbert space $\H$, which were found by Kirillov and Ol&#39;shanskii, are reconstructed from quantization theory. Firstly, the coadjoint orbits of this group are realized as Marsden-Wei

Mirjam Cvetic, Harald H. Soleng

We investigate gravitational effects of extreme, non-extreme and ultra- extreme domain walls in the presence of a dilaton field. The dilaton is a scalar field without self-interaction that couples to the matter po- tential that is responsible for the formation of the wall. Motivated by superstring and supergravity theories, we consider both an exponential di

S. A. Lyakhovich, A. A. Sharapov

It is shown that the Sugawara-type construction for W3-algebra associated with the four magical Jordan algebras leads to the anomalous theory of W3-gravity.

Kiyoshi Ezawa

Setting an ansats that the metric is expressible by a power series of the inverse radius and taking a particular gauge choice, we construct a &#34;general solution&#34; of (2+1)-dimensional Einstein&#39;s equations with a negative cosmological constant in the case where the spacetime is asymptotically anti-de Sitter. Our general solution turns out to be para

Mark Evans, Ioannis Giannakis

The gauge symmetries that underlie string theory arise from inner automorphisms of the algebra of observables of the associated conformal field theory. In this way it is possible to study broken and unbroken symmetries on the same footing, and exhibit an infinite-dimensional supersymmetry algebra that includes space-time diffeomorphisms and an infinite numbe

A. Kundu, S. Mallik

The generation of the baryon asymmetry of the universe is considered in the standard model of the electroweak theory with simple extensions of the Higgs sector. The propagation of quarks of masses up to about 5 GeV are considered, taking into account their markedly different dispersion relations due to propagation through the hot electroweak plasma. It is sh

B. Ananthanarayan, Saurabh D. Rindani

Certain CP-odd momentum correlations in the production and subsequent decay of $\tau$ pairs in $e^+ e^-$ collisions are enhanced significantly when the $e^+$ and $e^-$ beams are longitudinally polarized. These may be used to probe the real and imaginary parts of $d_\tau^\gamma$, the electric dipole moment of the $\tau$. Closed-form expressions for these ``ve

Nir Polonsky

The status of coupling constant unification -- assuming the validity of the standard model or of its minimal supersymmetric extension at high energies -- and of relations between various Yukawa couplings (assuming the supersymmetri extension) which are implied in certain grand-unified theories, are studied in detail. Theoretical uncertainties in the calculat

M. A. Braun

The equation proposed by N.N.Nikolaev, B.G.Zakharov and V.R.Zoller for the colour dipole cross-section is compared with the BFKL equation for the hard pomeron for the $SU(2)$ colour group. It is demonstrated that for a fixed coupling constant the difference between the two equations is due to a different manner to introduce the gluon mass.

L. M. Sehgal

The rare decays of the $K$ meson have had a long tradition as a laboratory for testing the symmetry properties of the weak interactions, and the manner in which these symmetries are broken by higher order effects. Present--day interest is focussed on decays that are suppressed by $CP$--symmetry or GIM symmetry. Such decays, in the standard theory, are sensit