September 1993 arXiv papers — page 2

A. Smailagic, Euro Spallucci

We study the residual symmetry $SL(2,R)\otimes U(1)$ of the chiral gravity in the light-cone gauge. Quantum gravitational effects renormalize the Kac-Moody central charge and introduce, through the Lorentz anomaly, an arbitrary parameter. Due to the presence of this free parameter the Kac-Moody central charge has no forbidden range of values, and the strong

Koji Harada, Takanori Sugihara, Masa-aki Taniguchi, Masanobu Yahiro

The massive Schwinger model with two flavors is studied in the strong coupling region by using light-front Tamm-Dancoff approximation. The mass spectrum of the lightest particles is obtained numerically. We find that the mass of the lightest isotriplet (``pion'') behaves as $m^{0.50}$ for the strong couplings, where $m$ is the fermion mass. We also f

A. A. Anselm, Myron Bander

High energy reactions may produce a state around the collision point that is best described by a classical pion field. Such a field might be an isospin rotated vacuum of the chiral $σ$-model or, as discussed in this work, a solution of the equations of motion resultinng from the coupling of fields of this model to quarks produced in the collision. In such co

A. A. Likhoded, A. A. Pankov, N. Paver, M. V. Shevlyagin

We study the potential of the next-generation $e^+ e^-$ linear colliders with longitudinally polarized beams, to restrict the values of the anomalous trilinear couplings $WWγ$ and $WWZ$ from the measurement of the process $e^+ e^-\to W^+ W^-$. Along with initial $e^+e^-$ polarization, we account also for the possibilities offered by cross sections for polari

M. Hayakawa, T. Kurimoto, A. I. Sanda

A chiral Lagrangian with $ SU(3) $ breaking and higher resonances is proposed. In this model, the $ SU(3) $ breaking structure in vector-pseudoscalar sector is realized with the decay constants of pseudoscalar mesons and the masses of vector mesons used as inputs. We examine whether the resulting $ SU(3) $ breaking effect in the charge radii of pseudoscalar

Dirk-Uwe Jungnickel, Dirk Walliser

We investigate the effects of inhomogeneous scalar field configurations on the electroweak phase transition. For this purpose we calculate the leading perturbative correction to the wave function correction term $Z(\vph,T)$, i.e., the kinetic term in the effective action, for the electroweak Standard Model at finite temperature and the top quark self--mass.

Michael Creutz

Lattice gauge theory is our primary tool for the study of non-perturbative phenomena in hadronic physics. In addition to giving quantitative information on confinement, the approach is yielding first principles calculations of hadronic spectra and matrix elements. After years of confusion, there has been significant recent progress in understanding issues of

R. R. Caldwell

A method for calculating the retarded Green's function for the gravitational wave equation in Friedmann-Roberson-Walker spacetimes, within the formalism of linearized Einstein gravity is developed. Hadamard's general solution to Cauchy's problem for second-order, linear partial differential equations is applied to the FRW gravitational wave equat

Kikuo Harigaya, G. A. Gehring

The elastic anomaly observed in the coherent Kondo state of Ce heavy fermion compounds is analyzed by using the Anderson lattice model simulating the energy level scheme of CeTe. The $Γ_7$ doublets and $Γ_8$ quartets of the 4f states are considered in the model. We solve the mean field equations to derive the temperature dependences of elastic constants, usi

Dierk Bormann, Hans Beck

We study the two-dimensional Ginzburg-Landau model of a neutral superfluid in the vicinity of the vortex unbinding transition. The model is mapped onto an effective interacting vortex gas by a systematic perturbative elimination of all fluctuating degrees of freedom (amplitude {\em and} phase of the order parameter field) except the vortex positions. In the

N. Kawakami

An integrable model for SU($ν$) electrons with inverse-square interaction is studied for the system with confining harmonic potential. We develop a new description of the spectrum based on the {\it renormalized harmonic-oscillators} which incorporate interaction effects via the repulsion of energy levels. This approach enables a systematic treatment of the e

K. Vacek, A Okiji, N. Kawakami

An exactly solvable electron model of a confined system with inverse-square interaction is presented. The ground state is given by the Jastrow-product wavefunction of power-law form. We discuss the results in connection with conductance oscillations observed in semiconductor nanostructures, for which single-electron charging effects play a crucial role. Due

N. Kawakami

In a recent letter Johnson and Payne (JP) have studied the effect of the electron interaction on the periodic conductance oscillations in narrow channels based on an exactly solvable model. In this Comment we discuss the exchange-correlation effect on JP's model using a solvable electron model. We wish to point out that when the interaction strength beco

T. Theuns

A P3M (Particle-Particle, Particle-Mesh) algorithm to compute the gravitational force on a set of particles is described. The gravitational force is computed using Fast Fourier Transforms. This leads to an incorrect force when the distance between two particles is of the order of a grid cell. This incorrect force is subtracted exactly from all particles in p

James M. Cline, Kimmo Kainulainen, Sonia Paban

We show that there is no one-loop enhancement of the rate for a light neutrino to decay into a lighter neutrino plus a majoron, contrary to a recent claim. Thus the light neutrinos must satisfy the cosmological bound of having masses less than 35 eV in the singlet majoron model, or else violate the constraint imposed by galaxy formation. In the latter case,

Keith R. Dienes, Jean-Rene Cudell

We demonstrate that the Hagedorn-like growth of the number of observed meson states can be used to constrain the degrees of freedom of the underlying effective QCD string. We find that the temperature relevant for such string theories is not given by the usual Hagedorn value $T_H\approx 160$ MeV, but is considerably higher. This resolves an apparent conflict

J. S. Dowker

A technical point regarding the invariance of Polyakov's nonlocal form of the effective action under uniform rescalings is briefly addressed.

C. N. Pope

We present a review of the status of $W$ string theories, their physical spectra, and their interactions. (Based on review talks given at the Trieste Spring Workshop, and the Strings 93 meeting at Berkeley, May 1993.)

Michael Dine

We consider two questions in string ``phenomenology.'' First, are there any generic string predictions? Second, are there any general lessons which string theory suggests for thinking about low energy models, particularly in the framework of supersymmetry? Among the topics we consider are the squark and slepton spectrum, flavor symmetries, discrete s

U. Baur

The activities of the Electroweak Physics Working Group are summarized. Three main issues are addressed: 1) prospects for measuring the $W$ mass at the Tevatron using the inclusive electron energy spectrum, 2) constraining the strange quark distribution function in $W$ + charm production, and 3) possibilities to determine the three vector boson couplings at

John C. Collins

I will summarize the physics that can be investigated with polarized pp collisions. It is technically feasible to use the RHIC collider for accelerating highly polarized protons to a center-of-mass energy of about 400 GeV, with high luminosity. Such collisions can be used to probe the spin-dependence of hard collisions and of partons in a hadron, including t

Stephen Godfrey, T. G. Rizzo

We summarize the results of the extended gauge group working group of the Madison-Argonne Workshop on Present and Future Colliders. Contributions are described on the previously unexamined two photon fusion production of heavy leptons, new studies of $Z'$ couplings to $ν\barν$ and $q\bar{q}$, and previously unexplored vector leptoquark production. More d

E. Maina, R. Torasso

Pion Compton scattering is studied in perturbative QCD for real and space--like initial photons. Different methods for the convolution of the hard amplitude with the pion wave--functions, which have in the past led to conflicting results, are compared.

Ernest Ma

Baryon number (B) is automatically conserved in the standard SU(2) X U(1) electroweak gauge model, but not in its supersymmetric extension where it must be imposed as an extra condition. This undesirable feature is avoided in the conventional left-right supersymmetric extension, but then flavor-changing neutral currents (FCNC) are not naturally suppressed. A

Maarten F. L. Golterman, Karl Jansen, Donald N. Petcher, Jeroen C. Vink

We investigate a recent proposal to construct chiral gauge theories on the lattice using domain wall fermions. We restrict ourselves to the finite volume case, in which two domain walls are present, with modes of opposite chirality on each of them. We couple the chiral fermions on only one of the domain walls to a gauge field. In order to preserve gauge inva

Guillermo A. Mena Marugan

We carry out the nonperturbative canonical quantization of several types of cosmological models that have already been studied in the geometrodynamic formulation using the complex path-integral approach. We establish a relation between the choices of complex contours in the path integral and the sets of reality conditions for which the metric representation

José P. S. Lemos, Paulo M. Sá

We show that the two-dimensional theory of Teitelboim and Jackiw has a black hole solution, with two surprising properties: first, it has constant curvature, and second, is free of spacetime singularities. The maximally extended spacetime consists of an infinite chain of universes connected by timelike wormholes.

J. S. Bagla, T. Padmanabhan

: From the epoch of recombination $(z\approx 10^3)$ till today, the typical density contrasts have grown by a factor of about $10^6$ in a Friedmann universe with $Ω=1$. However, during the same epoch the typical gravitational potential has grown only by a factor of order unity. We present theoretical arguments explaining the origin of this approximate consta

Emilia Mezzetti

Let $X$ be an integral projective variety of codimension two, degree $d$ and dimension $r$ and $Y$ be its general hyperplane section. The problem of lifting generators of minimal degree $σ$ from the homogeneous ideal of $Y$ to the homogeneous ideal of $X$ is studied. A conjecture is given in terms of $d$, $r$ and $σ$; it is proved in the cases $r=1,2,3$. A d

Wei Chen, Chigak Itoi

Not only does Chern-Simons (CS) coupling characterize statistics, but also spin and scaling dimension of matter fields. We demonstrate spin transmutation in relativistic CS matter theory, and moreover show equivalence of several models. We study CS vector model in some details, which provide consistent check to the assertion of the equivalence.

M. Chaichian, J. L. Lucio M., C. Montonen, H. Perez Rojas

Renormalization in quantum statistics in the presence of a charge associated to a spontaneously broken symmetry is discussed for the scalar field model. In contrast to the case of non-broken symmetry, the renormalization mass counterterm depends on the chemical potential. We argue that this is connected to the ill-defined character of the charge operator.

M. Jimbo, T. Kojima, T. Miwa, Y. -H. Quano

We study the quantum Knizhnik-Zamolodchikov equation of level $0$ associated with the spin $1/2$ representation of $U_q \bigl(\widehat{\frak s \frak l _{2}}\bigr)$. We find an integral formula for solutions in the case of an arbitrary total spin and $|q|<1$. In the formula, different solutions can be obtained by taking different integral kernels with the cyc

Denise E. Freed

In this paper we consider 1-D non-local field theories with a particular $1/r^2$ interaction, a constant gauge field and an arbitrary scalar potential. We show that any such theory that is at a renormalization group fixed point also satisfies an infinite set of reparametrization invariance Ward identities. We also prove that, for special values of the gauge

S. Aoki, H. Hirose

Perturbation theory for lattice fermions with domain wall mass terms is developed and is applied to investigate the chiral Schwinger model formulated on the lattice by Kaplan&#39;s method. We calculate the effective action for gauge fields to one loop, and find that it contains a longitudinal component even for anomaly-free cases. From the effective action w

Attila Csoto, Daniel Baye

The beta delayed deuteron emission from $^6$He is studied in a dynamical microscopic cluster model. This model gives a reasonably good description for all the subsystems of $^6$He and $^6$Li in a coherent way, without any free parameter. The beta decay transition probability to the $^6$Li ground state is underestimated by a few percents. The theoretical beta

H. Thomas Williams

A presentation of the problem of calculating the vector coupling coefficients for $SU3 \supset SU2 \otimes U1$ is made, in the spirit of traditional treatments of SU2 coupling. The coefficients are defined as the overlap matrix element between product states and a coupled state with good SU3 quantum numbers. A technique for resolution of the outer degeneracy

Petr Horava

We identify and examine a generalization of topological sigma models suitable for coupling to topological open strings. The targets are Kahler manifolds with a real structure, i.e. with an involution acting as a complex conjugation, compatible with the Kahler metric. These models satisfy axioms of what might be called ``equivariant topological quantum field

T. Fukui

The self-similar potentials are formulated in terms of the shape-invariance. Based on it, a coherent state associated with the shape-invariant potentials is calculated in case of the self-similar potentials. It is shown that it reduces to the q-deformed coherent state.

M. Chaichian, R. Gonzales Felipe, C. Montonen

We find a class of nonlocal operators constructed by attaching a disorder operator to fermionic degrees of freedom, which can be used to generate q-deformed algebras following the Schwinger approach. This class includes the recently proposed anyonic operators defined on a lattice.

J. A. Minahan, A. P. Polychronakos

We consider $U(N)$ and $SU(N)$ gauge theory on the sphere. We express the problem in terms of a matrix element of $N$ free fermions on a circle. This allows us to find an alternative way to show Witten&#39;s result that the partition function is a sum over classical saddle points. We then show how the phase transition of Douglas and Kazakov occurs from this

H. Itoyama, T. Oota

The Sine-Gordon theory at $\frac{β^{2}}{8π} = \frac{2}{(2n+3)},\; n= 1,2,3 \cdots $ has a higher spin generalization of the $N=2$ supersymmetry with the central terms which arises from the affine quantum group $U_{q}( \hat{s \ell} (2))$. Observing that the algebraic determination of $S$ matrices $( \approx {\rm quantum~ integrability })$ requires the saturat

M. De Montigny, M. Masip

We investigate the presence of discrete gauge symmetries in Grand Unification models based in $SO(10)$ and $E_6$. These models include {\it flipped} and {\it unflipped} $SU(5)$, $SU(4)\!\times\! SU(2)_L\!\times\! SU(2)_R$, $SU(3)_C\!\times\! SU(3)_L\!\times\! SU(3)_R$, and $SU(6)\!\times\! SU(2)$. Using the Dynkin formalism we find the $U(1)$ subalgebras con

Dongsheng Liu

The renormalization effects from the b-quark scale down to the non-perturbative QCD regime are studied for rare $B$-decays at the heavy b-quark limit. Phenomenological consequences of these effects are investigated. We find that the anomalous scaling behavior plays a positive role in making non-perturbative model calculations consistent with recent CLEO meas

Sacha Davidson, David Bailey, Bruce A. Campbell

We present model independent constraints on the masses and couplings to fermions of $B$ and $L$ conserving leptoquarks. Such vector or scalar particles could have masses below 100 GeV and be produced at HERA; we list the generation dependent bounds that can be calculated from rare lepton and meson decays, meson-anti-meson mixing and various electroweak tests

M. Wallin, E. Sorensen, S. M. Girvin, A. P. Young

Universal properties of the zero temperature superconductor-insulator transition in two-dimensional amorphous films are studied by extensive Monte Carlo simulations of bosons in a disordered medium. We report results for both short-range and long-range Coulomb interactions for several different points in parameter space. In all cases we observe a transition

H. Jeong, B. Kahng, D. Kim

We present numerical data of the height-height correlation function and of the avalanche size distribution for the three dimensional Toom interface. The height-height correlation function behaves samely as the interfacial fluctuation width, which diverges logarithmically with space and time for both unbiased and biased cases. The avalanche size defined by th

Kasper Juel Eriksen, Per Hedegård

Inspired by recent experiments by Geim et al. we discuss the classical theory of the Hall effect of a 2 dimensional electron gas in an inhomogeneous magnetic field. The field modulation is in the form of flux tubes created by a superconductor overlayer. We find that an approach, where the vortices are treated as individual scatterers contributing to the coll

Volkhard Buchholtz, Thorsten Poeschel

The evolution of a pile of granular material is investigated by molecular dynamics using a new model including nonsphericity of the particles instead of introducing static friction terms. The angle of repose of the piles as well as the avalanche statistics gathered by the simulation agree with experimental results. The angle of repose of the pile is determin

Anatoly Klypin, George Rhee

We propose the zero-point of the cluster-cluster correlation function as a sensitive test for the shape of the power spectrum of initial fluctuations. It is now possible to go beyond the power law description to measure the point at which the correlation function becomes zero. Four independent measurements indicate that the zero point, $r_0$, should be in th

I. B. Khriplovich, A. I. Milstein, A. S. Yelkhovsky

The order $α^4 R_{\infty}$ corrections to positronium $P$ levels are found. The calculation is reduced to the ordinary perturbation theory for the nonrelativistic Schrödinger equation. The perturbation operators have the Breit-type structure and are obtained by calculating on-mass-shell diagrams. Found energy corrections constitute numerically $δE(2 ^1 P_1)=

Dominique Foata, Doron Zeilberger

Capelli&#39;s and Turnbull&#39;s classical identities are given elegant combinatorial proofs.

Antal Jevicki

Lectures presented at the Spring School, Trieste, Italy 1993.

Massimo Porrati

Various properties of open strings in external constant E.M. fields are reviewed. In particular, the charged-particle pair production rate in an external electric field is evaluated, and shown to reduce to Schwinger&#39;s formula in the limit of low-intensity fields. Open strings in external magnetic fields are shown to undergo an infinite number of phase tr

Ph. Blanchard, A. Jadczyk

Model interactions between classical and quantum systems are briefly discussed. These include: general measurement-like couplings, Stern-Gerlach experiment, model of a counter, quantum Zeno effect, SQUID-tank model.

Ph. Blanchard, A. Jadczyk

A model interaction between a two-state quantum system and a classical switching device is analysed and shown to lead to the quantum Zeno effect for large values of the coupling constant k . A minimal piecewise deterministic random process compatible with the Liouville equation is described, and it is shown that 1/k can be interpreted as the jump frequency o

K. Landsteiner, M. Langer, M. Schweda, S. P. Sorella

Chern-Simons theory is analyzed with a gauge-fixing which allows to discuss the Landau gauge and the light-cone gauge at the same time.

Christopher T. Hill

The possibility of exploring the systematics of the spectroscopy, strong dynamics, and the weak and rare decay modes of b--quark systems at hadron colliders such as Fermilab, LHC and SSC, is discussed. A copious yield of $10^{10}$ detected $B$--mesons is readily accessible in a dedicated Fermilab program, and implies a vast array of accessible decay modes, i

G. J. Stephenson, T. Goldman

We have examined the consequences of assuming the existence of a light scalar boson, weakly coupled to neutrinos, and not coupled to any other light fermions. For a range of parameters, we find that this hypothesis leads to the development of neutrino clusters which form in the early Universe and which provide gravitational fluctuations on scales small compa

Jonathan L. Rosner, Mihir P. Worah, Tatsu Takeuchi

The lowest-order expression for the partial $W$ width to $e ν,~Γ(W \to e ν) = G_μM_W^3 /(6 π\sqrt{2})$, has no oblique radiative corrections from new physics if the measured $W$ mass is used. Here $G_μ= (1.16639 \pm 0.00002) \times 10^{-5}$ GeV/$c^2$ is the muon decay constant. For the present value of $M_W = (80.14 \pm 0.27)$ GeV/$c^2$, and with $m_t = 140$

Ashok Das, V. S. Mathur

We present a general classification of all normal and ``chiral&#34; symmetries of heavy quark effective theories. Some peculiarities and conondrums associated with the ``chiral&#34; symmetries are discussed.

C. Gobbi, N. N. Scoccola

A version of the bound state soliton model which allows both $η$ and $K$ bound states is used to study low partial wave octet baryon resonances. It is found that negative parity $S-$wave resonances are well described within this framework. A possible interpretation of the $P-$wave resonances is also discussed.

J. R. Espinosa

In the Minimal Supersymmetric Standard Model (MSSM) the existence of an upper bound on the mass of the $CP=+1$ lightest Higgs boson, equal to $m_Z$ at tree--level and $\simlt 120\ GeV$ after the inclusion of radiative corrections, has important phenomenological consequences for Higgs searches. A similar bound, independent of mass parameters other than the el

S. Zouzou, J. -M. Richard

We use a bag model to study flavoured mesonic $(Qq\bar q\bar q)$ and baryonic $({\overline Q}qqqq)$ states, where one heavy quark $Q$ is associated with light quarks or antiquarks, and search for possible stable multiquarks. No bound state is found. However some states lie not too high above their dissociation threshold, suggesting the possibility of resonan

J. Schechter, A. Subbaraman, S. Surya

We compare the resonant and non-resonant contributions in various regions of phase space for the $D\rightarrow \bar{K}\p$ semileptonic transition amplitude, computed in a chiral model which incorporates the heavy quark symmetry. Remarks on the significance for experiment and for chiral perturbation theory are made. hep-ph/yymmnnn

D. S. Shaw, R. R. Volkas

An effective theory is proposed, combining the standard gauge group $SU(3)_{C}\otimes SU(2)_{L}\otimes U(1)_{Y}$ with a horizontal discrete symmetry. By assigning appropriate charges under this discrete symmetry to the various fermion fields and to (at least) two Higgs doublets, the broad spread of the fermion mass and mixing angle spectrum can be explained

Redouane Fakir

Recently, the possibility has emerged of an early detection of astrophysical gravity waves. In certain astronomical configurations, and through a new light-deflection effect, gravity waves can cause apparent shifts in stellar angular positions as large as $10^{-7}arcsec$. In these same configurations, the magnitude of the gravity-wave-induced time-delay effe

S. Carlip

This paper is a review of the relationship between the metric formulation of (2+1)-dimensional gravity and the loop observables of Rovelli and Smolin. I emphasize the possibility of reconstructing the geometry, via the theory of geometric structures, from the values of the loop variables. I close with a brief discussion of implications for quantization, part

W. O. Putikka, R. L. Glenister, R. R. P. Singh, H. Tsunetsugu

We have calculated high temperature expansions for the momentum distribution function $n_{\scriptscriptstyle\bf k}$ and the equal time spin and density correlation functions $S({\bf q})$ and $N({\bf q})$ of the two-dimensional $t$-$J$ model. On extrapolation to low temperatures we find that $n_{\scriptscriptstyle\bf k}$ has a step-like feature at ${\bf k}_{\

E. R. Mucciolo, B. S. Shastry, B. D. Simons, B. L. Altshuler

We present exact results for the dynamical structure function, i.e.~the density-density correlations for the 1/r^2 system of interacting particles at three special values of the coupling constant. The results are interpreted in terms of exact excitations of the model which are available from Bethe&#39;s Ansatz, thereby throwing light on the quasi-particle co

Nick Kaiser

I review a number of tests of theories for structure formation. Large-scale flows and IRAS galaxies indicate a high density parameter $Ω\simeq 1$, in accord with inflationary predictions, but it is not clear how this meshes with the uniformly low values obtained from virial analysis on scales $\sim$ 1Mpc. Gravitational distortion of faint galaxies behind clu

B. Banerjee, R. V. Gavai

The three phase transitions - the GUT, the electro-weak and the quark-hadron, which the universe is assumed to have undergone produce very important physical effects if they are assumed to be of first order. It is also important that enough supercooling is produced at these transitions so that the rate of nucleation of the lower temperature phase out of the

Sinan Sertoz

A holomorphic foliation is defined as an integrable coherent subsheaf of the tangent sheaf. The structure of the leaves around a singularity is read off from the structure of the stalks. This was done by Baum when the dimension of the singular set is one less than the leaf dimension. In this article we study the general case and construct some examples.

J. Distler, S. Kachru

A large class of (0,2) Calabi-Yau $σ$-models and Landau-Ginzburg orbifolds are shown to arise as different ``phases&#39;&#39; of supersymmetric gauge theories. We find a phenomenon in the Landau-Ginzburg phase which may enable one to understand which Calabi-Yau $σ$-models evade destabilization by worldsheet instantons. Examples of (0,2) Landau-Ginzburg vacua

Dallas C. Kennedy

Natural resource use and waste production, disposal, and reuse in human economies are treated in their economic, technological and thermodynamic aspects. The physical nature of economic production, consumption, saving, and waste is compared and contrasted with non-human ecologies in terms of entropy production and evolutionary complexity.

Miao Li

We show that string theory with Dirichlet boundaries is equivalent to string theory containing surfaces with certain singular points. Surface curvature is singular at these points. A singular point is resolved in conformal coordinates to a circle with Dirichlet boundary conditions. We also show that moduli parameters of singular surfaces coincide with those

A. Stange, W. Marciano, S. Willenbrock

The Wjj background has increased by 70%. This decreases the significance of the WH signal somewhat. The significance of the ZH signal remains about the same.

M. Gaberdiel

Recently (hep-th/9307183) we showed that for the case of the WZW- and the minimal models fusion can be understood as a certain ring-like tensor product of the symmetry algebra. In this paper we generalize this analysis to arbitrary chiral algebras. We define the tensor product of conformal field theory in the general case and prove that it is associative and

W. R. Greenberg, G. A. Miller

Color transparency (CT) in high momentum transfer $(e,e&#39; \vec p)$ reactions is explored. The spin of the proton and photon are treated explicitly, hence the name ``Vector CT&#34;. The Dirac distorted wave impulse approximation is used as a starting point; then CT effects are embedded. A hadronic basis is used to describe the struck proton as a wavepacket

Tanmay Vachaspati

We give an action that can be used to describe the production of global vortices in 2+1 dimensions by scattering Nambu-Goldstone bosons. At strong self-coupling the action reduces to scalar QED with particular values of the coupling constants and the production cross-section is explicitly found. We also consider the production of gauged vortices by scatterin

M. Caselle, A. D&#39;Adda, L. Magnea, S. Panzeri

The partition functions of QCD2 on simple surfaces admit representations in terms of exponentials of the inverse coupling, that are modular transforms of the usual character expansions. We review the construction of such a representation in the case of the cylinder, and show how it leads to a formulation of QCD2 as a $c=1$ matrix model of the Kazakov-Migdal

I. R. Klebanov, I. I. Kogan, A. M. Polyakov

We study the gravitational dressing of renormalizable two-dimensional field theories. Our main result is that the one-loop $β$-function is finitely renormalized by the factor ${k+2\over k+1}$, where $k$ is the central charge of the gravitational $SL(2, R)$ current algebra.

Ann E. Nelson, Nathan Seiberg

We point out a connection between R symmetry and \susy\ breaking. We show that the existence of an R symmetry is a necessary condition for \susy\ breaking and a spontaneously broken R symmetry is a sufficient condition provided two conditions are satisfied. These conditions are: {\it genericity}, \ie\ the effective Lagrangian is a generic Lagrangian consiste

A. Djouadi, P. Gambino

We present the (two--loop) QCD corrections to the longitudinal and transverse components of the electroweak gauge bosons self--energies for arbitrary momentum transfer and for different internal quark masses. Compact formulae for both the real and imaginary parts are given in the general case as well as in some physically interesting special cases. The depen

Alexandr Andrianov, Vladimir Andrianov

In our lecture we discuss the fermion models with quasilocal interaction implemented by derivatives and a momentum cutoff as substitutes of QCD at low energies. They are investigated in the strong coupling regime when several coupling constants are matched to their critical values. It is found that around polycritical points there appear a number of resonanc

Marco Aurelio Diaz

The effect of loops involving charginos with up-type squarks, and gluinos with down-type squarks, on the inclusive decay mode $b\rightarrow sγ$ is studied in the context of minimal $N=1$ Supergravity models with a radiatively broken electroweak symmetry group. It is confirmed that the strong constraints imposed by the CLEO upper bound $B(b\rightarrow sγ)<5.4

Francesco Sannino

A strong violation of the $\displaystyle{ΔI = {1\over 2}} $ rule has experimentally been found in the $\displaystyle{D \to ππ}$ decays [1]. In this letter we will show that the order of magnitude of this violation can be understood in terms of the pure quantum chromo dynamics corrections to the weak interactions.

W. A. Bardeen, M. Carena, S. Pokorski, C. E. M. Wagner

We analyze the implications of the infrared quasi fixed point solution for the top quark mass in the Minimal Supersymmetric Standard Model. This solution could explain in a natural way the relatively large value of the top quark mass and, if confirmed experimentally, may be suggestive of the onset of nonperturbative physics at very high energy scales. In the

John N. Bahcall

A precise test of the theory of stellar evolution can be performed by measuring the difference in average energy between the neutrino line produced by ${\rm ^7Be}$ electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. The high temperatures in the center of the sun broaden the line asymmetrically, FWH

G. Nardulli

We describe two recent theoretical calculations of the $B \to K^* γ$ decay. The first method is based on an effective lagrangian incorporating chiral symmetry for the light degrees of freedom and the heavy quark spin-flavor symmetries for the heavy quarks. Using these symmetries, together with the hypothesis of polar q$^2$ dependence of the semileptonic form

Kenichiro Aoki

We compute some non--decoupling effects in the standard model, such as the $\rho$ parameter, to all orders in the coupling constant expansion. We analyze their large order behavior and explicitly show how it is related to the non--perturbative cutoff dependence of these non--decoupling effects due to the triviality of the theory.

E. Dagotto, J. Riera, Y. C. Chen, A. Moreo

Numerical and analytical studies of several models of correlated electrons are discussed. Based on exact diagonalization and variational Monte Carlo techniques, we have found strong indications that the two dimensional t-J model superconducts near phase separation in the regime of quarter-filling density, in agreement with previous results reported by Dagott

M. S. Deshpande, S. C. Erwin, S. Hong, E. J. Mele

An effective-medium theory for studying the electronic structure of the orientationally disordered A3C60 fullerides is developed and applied to study various normal-state properties. The theory is based on a cluster-Bethe-lattice method in which the disordered medium is modelled by a three-band Bethe lattice, into which we embed a molecular cluster whose sca

Steven C. Erwin, Christoph Bruder

Band theory predicts both K3C60 and K4C60 to be metals; various experimental probes show that while K3C60 is indeed metallic, K4C60 appears to be insulating. The standard view of this apparent failure of the single-particle picture is that electron correlation is predominant. We describe an alternative scenario, motivated on theoretical grounds, which invoke

Caleb. A. Scharf

In the rest of this volume Lahav and Fisher have presented the method of Spherical Harmonic Analysis (SHA) and its use in estimating cosmologically interesting parameters. Here I demonstrate the use of SHA in cross-correlating galazy catalogues and present an estimate of the ratio of the optical and IRAS galaxy bias parameters; b_O/b_I ~ 1.7.

Ofer Lahav

The orthonormal set of Spherical Harmonics provides a natural way of expanding whole sky redshift and peculiar velocity surveys.

Karl B. Fisher

We examine the nature of galaxy clustering in redshift space using a method based on an expansion of the galaxian density field in Spherical Harmonics and linear theory. We derive a compact and self-consistent expression for the distortion when applied to flux limited redshift surveys. The amplitude of the distortion is controlled by the combination of the d

S. Aoyama

We quantize the topological $σ$-model. The quantum master equation of the Batalin-Vilkovisky formalism $Δ_ρΨ= 0$ appears as a condition which eliminates the exact states from the BRST invariant states $Ψ$ defined by $Q Ψ= 0$. The phase space of the BV formalism is a supermanifold with a specific symplectic structure, called the fermionic Kähler manifold.

Larry McLerran, Raju Venugopalan

We argue that the distribution functions for quarks and gluons are computable at small x for sufficiently large nuclei, perhaps larger than can be physically realized. For such nuclei, we argue that weak coupling methods may be used. We show that the computation of the distribution functions can be recast as a many body problem with a modified propagator, a

Miriam Leurer

We show that FCNC processes are unavoidable for leptoquarks that couple to left handed quarks, and derive new FCNC bounds from neutral meson mixing. Despite being induced only at one loop, these processes lead to significant bounds since the leptoquark contributions do not suffer from GIM cancellations. Studying the implications of these bounds we find that

Avishai Dekel

The large-scale dynamics of matter is inferred from the observed peculiar velocities of galaxies via the POTENT procedure. The smoothed fields of velocity and mass-density fluctuations are recovered from the current data of about 3000 galaxies. The cosmological density parameter Omega can then be constrained in three ways: (a) by comparing the density fields