March 1995 arXiv papers — page 5

Christof Gattringer

QED_2 with mass and N flavors of fermions is constructed using Euclidean path integrals. The fermion masses are treated perturbatively and the convergence of the mass perturbation series is proven for a finite space-time cutoff. The expectation functional is decomposed into clustering theta-vacua and their properties are compared to the theta-vacua of QCD fo

Alfredo Iorio, Giuseppe Vitiello

We discuss the rôle of quantum deformation of Weyl-Heisenberg algebra in dissipative systems and finite temperature systems. We express the time evolution generator of the damped harmonic oscillator and the generator of thermal Bogolubov transformations in terms of operators of the quantum Weyl-Heisenberg algebra. The quantum parameter acts as a label for th

Giuseppe VITIELLO

We discuss dissipative systems in Quantum Field Theory by studying the canonical quantization of the damped harmonic oscillator (dho). We show that the set of states of the system splits into unitarily inequivalent representations of the canonical commutation relations. The irreversibility of time evolution is expressed as tunneling among the unitarily inequ

F. A. Lunev

It is shown that there exists such collection of variables that the standard QCD Lagrangian can be represented as the sum of usual Palatini Lagrangian for Einstein general relativity and the Lagrangian of matter and some other fields where the tetrad fields and the metric are constructed from initial $SU(3)$ Yang - Mills fields.

I. G. Avramidi

Using our recently proposed covariant algebraic approach the heat kernel for a Laplace-like differential operator in low-energy approximation is studied. Neglecting all the covariant derivatives of the gauge field strength (Yang-Mills curvature) and the covariant derivatives of the potential term of third order and higher a closed formula for the heat kernel

Deog Ki Hong

We note that in (2+1)-dimensional gauge theories with even number of massless fermions, there is anomalous $Z_2$ symmetry if theory is regularized in a parity-invariant way. We then consider a parity invariant $U(1)_V\times U(1)_A$ model, which induces a mutual Chern-Simons term in the effective action due to $Z_2$ anomaly. The effect of the discrete anomaly

A. A. Btysenko, S. D. Odintsov, S. Zerbini

The high temperature behaviour of the open bosonic string free energy in the space $S^1 \otimes H^N$ with vanishingly small curvature is investigated. The leading term of the high temperature expansion of the one-loop free energy, near the Hagedorn instability, is obtained. The problem of infrared regularization of thermodynamical quantities is pointed out.

Ralph Blumenhagen, Andreas Wisskirchen

We address the question whether so-called m-invariants of the N=2 super Virasoro algebra can be used for the construction of reasonable four-dimensional string models. It turns out that an infinite subset of those are pathological in the sense that - although N=2 supersymmetric - the Ramond sector is not isomorphic to the Neveu-Schwarz sector. Consequently,

B. Rosenstein

I propose an approximation scheme for asymptotically free field theories combining both weak coupling and strong coupling series. The weak coupling expansion is used to integrate the high frequency modes and the resulting low energy effective theory is solved using the strong coupling expansion. In some models there exists an intermediate scale at which both

Robert G. Leigh, Riccardo Rattazzi

We reconsider post-inflation gravitino production, in the context of hidden sector supergravity models. We discuss the possible role of supersymmetry breaking from finite temperature effects in enhancing the rate for gravitino production and argue that there is no such enhancement. Our conclusion is based on a simple decoupling argument, which is independent

Markus H. Thoma

A recent development in finite temperature field theory, the so-called Braaten-Pisarski method, and its application to properties of a quark-gluon plasma, possibly formed in relativistic heavy ion collisions, are reviewed. In particular parton damping rates, the energy loss of energetic partons, thermalization times, viscosity, and production and damping rat

Eugene Levin

These lectures are the review of the main ideas and approaches to the structure of the Pomeron. They are divided in three natural parts: (i) the brief review of the Reggeon Calculus, which was the first attempt to build the effective theory of the strong interaction at high energy. In spite of the fact that this approach turns out to be inconsistent and in l

Andreas DABELSTEIN, Wolfgang HOLLIK, Christoph JUENGER, Ricardo A. JIMENEZ

We compute the one-loop supersymmetric QCD quantum effects on the width $Γ(t\rightarrow W^{+}\, b)$ of the canonical main decay of the top quark within the framework of the MSSM. The corrections can be of either sign depending on whether the stop squark mass is above or below the top quark decay threshold into stop and gluino $Γ(t\rightarrow\tilde{t} \,\tild

T. Csorgo, L. P. Csernai

The time-scales of rehadronization are considered for a baryon-free QGP at RHIC and LHC energies. The non-equilibrium nucleation scenario leads to mechanical instability of the supercooled QGP phase which then may be suddenly converted in a timelike deflagration from the supercooled state to a (super)heated hadronic matter. In a model simulation such a sudde

K. G. Chetyrkin, J. H. Kühn, A. Kwiatkowski

QCD corrections to the electron positron annihilation cross-section into hadrons and to the hadronic $Z$ boson decay rate are reviewed. Formal developments are introduced in a form particularly suited for practical applications. These include the operator product expansion, the heavy mass expansion, the decoupling of heavy quarks and matching conditions. Exa

Tetsuo Hatsuda, Hiroyuki Shiomi

We summarize the current theoretical and experimental status of the spectral change of the vector mesons in dense matter.

E. Gotsman, E. M. Levin, U. Maor

The effects of shadowing in double Pomeron exchange processes are investigated within an eikonal approach with a Gaussian input. Damping factors due to screening are calculated for this process and compared with the factors obtained for total, elastic and single diffraction cross sections. Our main conclusion is that counting rate calculations, of various do

Martin Bucher, Neil Turok

We calculate the power spectrum of adiabatic density perturbations in an open inflationary model in which inflation occurs in two stages. First an epoch of old inflation creates a large, smooth universe, solving the horizon and homogeneity problems. Then an open universe emerges through the nucleation of a single bubble, with constant density hypersurfaces i

Hitoshi Murayama

I discuss non-trivial effects in the soft SUSY breaking terms which appear when one integrates out heavy fields. The effects exist only when the SUSY breaking terms are non-universal. They may spoil (1) the hierarchy between the weak and high-energy scales, or (2) degeneracy among the squark masses even in the presense of a horizontal symmetry. I argue, in t

R. Altendorfer, T. Kobayashi

We study the gauge coupling unification of the minimal supersymmetric standard model with non-universal soft scalar and gaugino masses. The unification scale of the gauge couplings is estimated for non-universal cases. It is sensitive to the non-universality. It turns out that these cases can be combined with the assumption of string unification, which leads

Neil J. Cornish

The simplest solution to the black hole information loss problem is to eliminate black holes. Modifications of Einstein gravity which accomplish this are discussed and the possibility that string theory is free of black holes is considered.

Jan de Boer, Andreas Schadschneider

We present a simple method for the construction of exact ground states of generalized Hubbard models in arbitrary dimensions. This method is used to derive rigorous criteria for the stability of various ground state types, like the $η$-pairing state, or Néel and ferromagnetic states. Although the approach presented here is much simpler than the ones commonly

Yue Yu, Yanmin Li, Nick d'Ambrumenil

We consider a magnetic impurity coupled to the hybridizing and screening channels of a conduction band. The model is solved in the framework of poor man's scaling and Cardy's generalized theories. We point out that it is important to include a two-body hybridization if the scaling theory is to be valid for the band width larger than $U$. We map out t

D. Weinmann, A. Mueller-Groeling, J. -L. Pichard, K. Frahm

The full spectrum of two interacting electrons in a disordered mesoscopic one--dimensional ring threaded by a magnetic flux is calculated numerically. For ring sizes far exceeding the one--particle localization length $L_1$ we find several $h/2e$--periodic states whose eigenfunctions exhibit a pairing effect. This represents the first direct observation of i

P. Šmilauer, S. Harris

We use analytic formulae obtained from a simple model of crystal growth by molecular--beam epitaxy to determine step--edge barriers to interlayer transport. The method is based on information about the surface morphology at the onset of nucleation on top of first--layer islands in the submonolayer coverage regime of homoepitaxial growth. The formulae are tes

T. Kaneko, P. Šmilauer, B. A. Joyce, T. Kawamura

We report the first observation of re-entrant layer-by-layer etching based on {\it in situ\/} reflection high-energy electron-diffraction measurements. With AsBr$_3$ used to etch GaAs(001), sustained specular-beam intensity oscillations are seen at high substrate temperatures, a decaying intensity with no oscillations at intermediate temperatures, but oscill

C. Ratsch, P. Šmilauer, A. Zangwill, D. D. Vvedensky

The nucleation and growth of two--dimensional islands is studied with Monte Carlo simulations of a pair--bond solid--on--solid model of epitaxial growth. The conventional description of this problem in terms of a well--defined critical island size fails because no islands are absolutely stable against single atom detachment by thermal bond breaking. When two

Marten Trautwein

In this paper, we assess the complexity results of formalisms that describe the feature theories used in computational linguistics. We show that from these complexity results no immediate conclusions can be drawn about the complexity of the recognition problem of unification grammars using these feature theories. On the one hand, the complexity of feature th

Leen Torenvliet, Marten Trautwein

The recognition problem for attribute-value grammars (AVGs) was shown to be undecidable by Johnson in 1988. Therefore, the general form of AVGs is of no practical use. In this paper we study a very restricted form of AVG, for which the recognition problem is decidable (though still NP-complete), the R-AVG. We show that the R-AVG formalism captures all of the

Giovanni Gallavotti

The KAM theorem from a combinatorial viewpoint.

P. Molaro, F. Primas, P. Bonifacio

Lithium abundances in a sample of halo dwarfs have been redetermined by using the new T$_{eff}$ derived by Fuhrmann et al (1994) from modelling of the Balmer lines. These T$_{eff}$ are reddening independent, homogeneous and of higher quality than those based on broad band photometry. Abundances have been derived by generating new atmospheric models by using

Edvige Corbelli, Andrea Ferrara

We present a linear analysis of acoustic and thermo-reactive instabilities in a diffuse gas, photoionized and heated by a radiation field, cooled by collisional excitation of hydrogen and metal lines. The hydrogen recombination reaction has a stabilizing effect on the thermal mode found by Field (1965) since the condensation instability occurs in a narrower

Edvige Corbelli, Edwin E. Salpeter

We discuss a possible delay experienced by protogalaxies with low column density of gas in forming stars over large scales. After the hydrogen has recombined, as the external ionizing UV flux decreases and the metal abundance $Z$ increases, the HI, initially in the warm phase ($T\simgt 5000$ K), makes a transition to the cool phase ($T\simlt 100$ K). The min

Aldo Treves, Ewa Szuszkiewicz

We consider the current flow in an accreting rotating neutron star (X-ray pulsator) and propose that the active magnetosphere is limited by the Alfvèn surface. Formulae for the luminosity and torque due to currents circulating in the neutron star are given, and astrophysical consequences for systems like Her X-1 and LMXRB are shortly discussed.

J. S. Bagla, T. Padmanabhan

We study the evolution of the power spectrum of gravitational potential during the nonlinear clustering in an $Ω=1$ matter dominated phase. N-body simulations suggest that the potential does not evolve in time even in the quasilinear phase for an $n=-1$ power spectrum. For $n=-2$, the potential evolves in the quasilinear phase but not in the extreme nonlinea

Gert-Martin Greuel, Christoph Lossen

We consider flat families of reduced curves on a smooth surface S such that each member C has the same number of singularities of fixed singularity types and the corresponding (locally closed) subscheme H of the Hilbert scheme of S. We are mainly concerned with analytic resp. topological singularity types and give a sufficient condition for the smoothness of

B. Enriquez, V. Rubtsov

We adapt Hitchin's integrable systems to the case of a punctured curve. In the case of $\CC P^{1}$ and $SL_{n}$-bundles, they are equivalent to systems studied by Garnier. The corresponding quantum systems were identified by B. Feigin, E. Frenkel and N. Reshetikhin with Gaudin systems. We give a formula for the higher Gaudin operators, using results of R

J. Ohnemus

The QCD radiative corrections to hadronic diboson production are reviewed. The radiative corrections for $W^{\pm}\gamma$, $Z\gamma$, $ZZ$, $W^+W^-$, and $W^{\pm} Z$ are discussed. Similarities and differences in the behavior of the order $\alpha_s$ cross sections for these processes are emphasized.

H. G. Dosch, O. Nachtmann, Michael Rueter

We re-derive and discuss two low energy theorems which relate the potential of a static quark-antiquark pair with the total energy and action stored in the flux tube between the sources. In lattice QCD these relations are known as Michael's sum-rules, but we give an essential correction to one of them. Then we relate the low energy theorems to the virial

Edward Witten

The strong coupling dynamics of string theories in dimension $d\geq 4$ are studied. It is argued, among other things, that eleven-dimensional supergravity arises as a low energy limit of the ten-dimensional Type IIA superstring, and that a recently conjectured duality between the heterotic string and Type IIA superstrings controls the strong coupling dynamic

T. Inui, Y. Mimura, N. Sakai, T. Sasaki

Neutron electric dipole moment (EDM) due to single quark EDM and to the transition EDM is calculated in the minimal supersymmetric standard model. Assuming that the Cabibbo-Kobayashi-Maskawa matrix at the grand unification scale is the only source of CP violation, complex phases are induced in parameters of soft supersymmetry breaking at low energies. Chargi

E. O. Alt, A. M. Mukhamedzhanov

The asymptotic behavior of the optical potential, describing elastic scattering of a charged particle $α$ off a bound state of two charged, or one charged and one neutral, particles at small momentum transfer $Δ_α$ or equivalently at large intercluster distance $ρ_α$, is investigated within the framework of the exact three-body theory. For the three-charged-

Donald E. Knuth

Shapley and Scarf introduced a notion of stable allocation between traders and indivisible goods, when each trader has rank-ordered each of the goods. The purpose of this note is to prove that the distribution of ranks after allocation is the same as the distribution of search distances in uniform hashing, when the rank-orderings are independent and uniforml

W. Banaszczyk, Stanislaw J. Szarek

Let $\| \cdot \|$ be the euclidean norm on ${\bf R}^n$ and $γ_n$ the (standard) Gaussian measure on ${\bf R}^n$ with density $(2 π)^{-n/2} e^{- \| x\|^2 /2}$. Let $\vartheta$ ($ \simeq 1.3489795$) be defined by $γ_1 ([ - \vartheta /2, \vartheta /2]) = 1/2$ and let $L$ be a lattice in ${\bf R}^n$ generated by vectors of norm $\leq \vartheta$. Then, for any cl

I. Juhász, Lajos Soukup, Z. Szentmiklóssy

We show that all finite powers of a Hausdorff space X do not contain uncountable weakly separated subspaces iff there is a c.c.c poset P such that 1_P forces that ``X is a countable union of 0-dimensional subspaces of countable weight.'' We also show that this theorem is sharp in two different senses: (i) we can't get rid of using generic extensi

John H. Schwarz

A brief review of the status of duality symmetries in string theory is presented. The evidence is accumulating rapidly that an enormous group of duality symmetries, including perturbative T dualities and non-perturbative S-dualities, underlies string theory. It is my hope that an understanding of these symmetries will suggest the right way to formulate non-p

Jorge Gamboa, Jorge Zanelli

The possibility of excitations with fractional spin and statististics in $1+1$ dimensions is explored. The configuration space of a two-particle system is the half-line. This makes the Hamiltonian self-adjoint for a family of boundary conditions parametrized by one real number $γ$. The limit $γ\rightarrow 0, (\infty$) reproduces the propagator of non-relativ

Spenta R. Wadia

We present a brief overview of 2-dim. string theory and its connection to the theory of non-relativistic fermions in one dimension. We emphasize (i) the role of $W_\infty$ algebra and (ii) the modelling of some aspects of 2-dim. black hole physics using the phase space representation of the fermi fluid.

Choonkyu Lee, Piljin Yi

The Lee-Weinberg $U(1)$ magnetic monopoles, which have been reinterpreted as topological solitons of a certain non-Abelian gauged Higgs model recently, are considered for some specific choice of Higgs couplings. The model under consideration is shown to admit a Bogomol'nyi-type bound which is saturated by the configurations satisfying the generalized BPS

F. Toppan

It is shown that modular invariance provides a natural explanation for the absence of monopoles when assumed to be a discrete gauge symmetry. It follows that monopoles can not be seen because it is always possible to find a suitable gauge-fixing in which they are not present. This result relies upon an easy to prove but non-trivial property of the modular gr

Robert G. Leigh, Matthew J. Strassler

We show that manifolds of fixed points, which are generated by exactly marginal operators, are common in N=1 supersymmetric gauge theory. We present a unified and simple prescription for identifying these operators, using tools similar to those employed in two-dimensional N=2 supersymmetry. In particular we rely on the work of Shifman and Vainshtein relating

Stanley J. Brodsky

Despite the many empirical successes of QCD, there are a number of intriguing experimental anomalies that have been observed in heavy flavor hadroproduction, in measurements of azimuthal correlations in deep inelastic processes, and in measurements of spin correlations in hadronic reactions. Such phenomena point to color coherence and multiparton correlation

A. N. Kamal, A. B. Santra, T. Uppal, R. C. Verma

With the inclusion of nonfactorized amplitudes in a scheme with $N_c=3$, we have studied Cabibbo-favored decays of $D^0$ and $D^+$ into two-body hadronic states involving two isospins in the final state. We have shown that it is possible to understand the measured branching ratios and determined the sizes and signs of nonfactorized amplitudes required.

Kingman Cheung

I summarize an update on our previous study (J. Bagger et al. Phys. Rev. D49, 1246) for a strongly interacting electroweak symmetry breaking sector via longitudinal vector boson scattering at the 14 TeV Large Hadron Collider. In the update, the decay mode $ZZ\to \ell^+\ell^- ν\bar ν$ and a new vector-resonance signal via $q\bar q' \to V \to W^+W^-/ W^\pm

B. Kerbikov

We predict that production of the K+K- atom in pd-3^HeX and similar reactions exhibits a drastic missing mass spectrum due to the interplay with f_0(975) resonance. We point out that high precision studies of the K+K- atom may shed a new light on the nature of f_0(975).

Gerhard A. Schuler, Torbjörn Sjöstrand

The structure of the general solution of the inhomogeneous evolution equations allows the separation of a photon structure function into perturbative (``anomalous") and non-perturbative contributions. The former part is fully calculable, and can be identified with the high-mass contributions to the dispersion integral in the photon mass. Properly normali

Chang-Hwan Lee, Mannque Rho

This article combines two talks given by the authors and is based on works done in collaboration with G.E. Brown and D.-P. Min on kaon condensation in dense baryonic medium treated in chiral perturbation theory using heavy-baryon formalism. It contains, in addition to what was recently published, astrophysical backgrounds for kaon condensation discussed by B

E. Laenen, E. Levin

We propose a new evolution equation for the gluon density relevant for the region of small $x_B$. It generalizes the GLR equation and allows deeper penetration in dense parton systems than the GLR equation does. This generalization consists of taking shadowing effects more comprehensively into account by including multigluon correlations, and allowing for an

Luca Cheli

We simulate the resolution power of a simple spectrometer with exemplificative magnetic fields for the πtagging in the $Λ\ \rightarrow \ p π$ decay for fixed target type experiments.

As. Abada

We present the results of a numerical calculation of the $B\to K^* γ$ form factors. The results have been obtained by studying the relevant correlation functions at $β=6.0$, on an $18^3 \times 64$ lattice, using the ${\rm O(a)}$-improved fermion action, in the quenched approximation. From the study of the matrix element $<K^*| \bar s σ_{μν} b | B>$ we have o

R. R. Zapatrin

In the last decades the logico-algebraic approach to quantum mechanics turned to be a successful tool to render the quantum mechanical formalism on a steady operationalistic background. The algebraic approach to general relativity first proposed by Geroch is used to build a smearing procedure for events in the quantized theory of spacetime. It stems from the

M. A. Yurishchev

A fully anisotropic simple-cubic Ising lattice in the geometry of periodic cylinders $n\times n\times\infty$ is investigated by the transfer-matrix finite-size scaling method. In addition to the previously obtained critical amplitudes of the inverse correlation lengths and singular part of the free energy [M. A. Yurishchev, Phys. Rev. B 50, 13 533 (1994)], t

N. Schultka, E. Manousakis

We study the specific heat of the $x-y$ model on lattices $L \times L \times H$ with $L \gg H$ (i.e. on lattices representing a film geometry) using the Cluster Monte--Carlo method. In the $H$--direction we apply Dirichlet boundary conditions so that the order parameter in the top and bottom layers is zero. We find that our results for the specific heat of v

A. J. Millis, L. B. Ioffe, H. Monien

The phenomenology and theory of spin gap effects in high temperature superconductors is summarized. It is argued that the spin gap behavior can only be explained by a model of charge 0 spin 1/2 fermions which become paired into singlets and that there are both theoretical and experimental reasons for believing that the pairing is greatly enhanced in the bila

Sanjay Puri, A. J. Bray, F. Rojas

The zero-temperature ordering kinetics of conserved XY models in spatial dimensions $d=2$ and 3 is studied using cell dynamical simulations. The growth of the characteristic length scale $L(t)$ is fully consistent with recent theoretical predictions: $L(t) \sim t^{1/4}$ for $d=2$ and $L(t) \sim (t\ln t)^{1/4}$ for $d=3$. A gaussian closure approximation desc

J. Froehlich, U. M. Studer, E. Thiran

In this paper, the key ideas of characterizing universality classes of dissipation-free (incompressible) quantum Hall fluids by mathematical objects called quantum Hall lattices are reviewed. Many general theorems about the classification of quantum Hall lattices are stated and their physical implications are discussed. Physically relevant subclasses of quan

M. L. Titov, A. G. Yashenkin, D. N. Aristov

We calculate the damping of excitations due to four-fermionic interaction in the case of two-dimensional superconductor with nodes in the spectrum. At zero temperature and low frequencies it reveals gapless $ω^3$ behavior at the nodal points. With the frequency increasing the crossover to the normal-state regimes appears. At high frequencies the damping stro

Tohru Kawarabayashi, Tomi Ohtsuki

Diffusion of electrons in a two-dimensional system in static random magnetic fields is studied by solving the time-dependent Schrödinger equation numerically. The asymptotic behaviors of the second moment of the wave packets and the temporal auto-correlation function in such systems are investigated. It is shown that, in the region away from the band edge, t

I. Aduriz, I. Alegria, J. M. Arriola, X. Artola

This paper presents relevant issues that have been considered in the design of a general purpose lemmatizer/tagger for Basque (EUSLEM). The lemmatizer/tagger is conceived as a basic tool necessary for other linguistic applications. It uses the lexical data base and the morphological analyzer previously developed and implemented. Due to the characteristics of

David D. Palmer

This paper provides a detailed description of the sentence segmentation system first introduced in cmp-lg/9411022. It provides results of systematic experiments involving sentence boundary determination, including context size, lexicon size, and single-case texts. Also included are the results of successfully adapting the system to German and French. The sou

James E. Rhoads

Near infrared light at 2 micrometers is relatively insensitive to the presence of hot young stars and dust in galaxies, and there has been recent interest in using it as a mass tracer in spiral galaxies. I present evidence that young, cool supergiant stars, whose presence is indicated by strong CO absorption in a 2.36 micrometer bandpass, dominate the 2 micr

Max Pettini, Keith Lipman

Whether the H II regions of dwarf emission-line galaxies are self-polluted by the nucleosynthetic products of massive stars remains an open question, despite recent claims to the contrary. We show that the finding by Kunth and collaborators that the neutral interstellar medium of I Zw 18 has a metallicity one order of magnitude lower than that of the ionized

Yu. V. Baryshev F. Sylos Labini M. Montuori L. Pietronero

A review of the principles of observational testing of cosmological theories is given with a special emphasis on the distinction between observational facts and theoretical hypotheses. A classification of modern cosmological theories and possible observational tests for these theories is presented. The main rival cosmological models are analyzed from the poi

L. Legrand, I. Rosenman, R. G. Mints, G. Collin

We show that the self-organized criticality of the Bean&#39;s state in each of the grains of a granular superconductor results in magneto-thermal oscillations preceding a series of subsequent flux jumps. We find that the frequency of these oscillations is proportional to the external magnetic field sweep rate and is inversely proportional to the square root

O. K. Kalashnikov

A tensor representation of the gluon propagator is found within covariant gauges for a non-Abelian theory after symmetry breaking due to $<A_0>\ne 0$ and the exact equations which determine the dispersion laws of plasma excitations are explicitly obtained. In the high temperature region and fixing the Feynman gauge we solved these equations and found the dam

Raju Venugopalan

We construct a weak coupling, many body theory to compute parton distributions in large nuclei for $x\ll A^{-1/3}$. The wee partons are highly coherent, non--Abelian Weizsäcker--Williams fields. Radiative corrections to the classical results are discussed. The parton distributions for a single nucleus provide the initial conditions for the dynamical evolutio

J. Papavassiliou, K. Philippides

In the context of the Standard Model we extend the S--matrix pinch technique for non--conserved currents to the case of three boson vertices. We outline in detail how effective gauge invariant three boson vertices can be constructed, with all three incoming momenta {\it off--shell}. Explicit closed expressions for the vertices $γW^- W^+$, $Z W^- W^+$, and $χ

F. Freire, Denjoe O&#39;Connor, C. R. Stephens

We analyze the specific heat for the $O(N)$ vector model on a $d$-dimensional film geometry of thickness $L$ using ``environmentally friendly&#39;&#39; renormalization. We consider periodic, Dirichlet and antiperiodic boundary conditions, deriving expressions for the specific heat and an effective specific heat exponent, $α\ef$. In the case of $d=3$, for $N=

J. Milana

Using perturbative QCD, the contribution at the leading twist, leading $α_s$ level, of charm and up quark loops to the decays $B \rightarrow K^* γ$ and $B \rightarrow ργ$ is presented. In the case of $B \rightarrow ργ$, the relative importance of these contributions depend upon the unknown CKM matrix elements $V_{bu}$ and $V_{td}$. Assuming that the ratio $r

S. Krivonos, A. Sorin

We show that a wide class of $W$-(super)algebras, including $W_N^{(N-1)}$, $U(N)$-superconformal as well as $W_N$ nonlinear algebras, can be linearized by embedding them as subalgebras into some {\em linear} (super)conformal algebras with finite sets of currents. The general construction is illustrated by the example of $W_4$ algebra.

M. Alimohammadi, A. Shafei Deh Abad

After showing that the magnetic translation operators are not the symmetries of the QHE on non-flat surfaces , we show that there exist another set of operators which leads to the quantum group symmetries for some of these surfaces . As a first example we show that the $su(2)$ symmetry of the QHE on sphere leads to $su_q(2)$ algebra in the equator . We expla

M. J. Graf, Mario Palumbo, D. Rainer, J. A. Sauls

We calculate the infrared conductivity of a stack of coupled, two-dimensional superconducting planes within the Fermi liquid theory of superconductivity. We include the effects of random scattering processes and show that the presence of even a small concentration of resonant impurities, in a $d$-wave superconductor, has an important effect on both the in-pl

N. E. Israeloff, M. Kagalenko, K. Chan

In a recent Physical Review Letter, Mantegna et. al., report that certain statistical signatures of natural language can be found in non-coding DNA sequences. In this comment we show that random noise with power-law correlation similar to $1/f$ noise, exhibits the same &#34;linguistic&#34; signature as those found in non-coding DNA. We conclude that these si

Scott Thomas

Moduli fields, which parameterize perturbative flat directions of the potential in supersymmetric theories, are natural candidates to act as inflatons. An inflationary potential on moduli space can result if the scale of dynamical SUSY breaking in some sector of the theory is determined by a moduli dependent coupling. The magnitude of density fluctuations ge

Kenneth A. Ribet

In this article, I discuss material which is related to the recent proof of Fermat&#39;s Last Theorem: elliptic curves, modular forms, Galois representations and their deformations, Frey&#39;s construction, and the conjectures of Serre and of Taniyama--Shimura.

Ngee Pong Chang

< \psibarpsi > vanishing above $T_c$ indicates chiral symmetry restoration at high $T$. But is it the old $T=0$ chiral symmetry that is `restored&#39;? In this talk, I report on the spacetime quantization of the BPFTW effective action for quarks in a hot environ. The fermion propagator is known to give a pseudo-Lorentz invariant particle pole as well as new

Kazuo Ghoroku

We have examined a modified dilaton gravity whose action is separable into the kinetic and the cosmological terms for the sake of the quantization. The black hole solutions survive even in the quantized theory, but the ADM mass of the static solution is unbounded from below. Quantum gravitational effect on the interacting matter field and the string suscepti

D. Finnell, P. Pouliot

We relate the non-perturbative exact results in supersymmetry to perturbation theory using several different methods: instanton calculations at weak or strong coupling, a method using gaugino condensation and another method relating strong and weak coupling. This allows many precise numerical checks of the consistency of these methods, especially the amplitu

T. Banks, M. Berkooz, G. Moore, S. H. Shenker

An exploratory study of the cosmology of moduli in string theory. Moduli are argued to be natural inflaton fields and lead to a robust inflationary cosmology in which inflation takes place at the top of domain walls. The amplitude of microwave background fluctuations constrains the dynamics responsible for inflation to take place at a higher scale than super

Gia Dvali

We discuss how the inflation induced supersymmetry breaking affects the flat directions of SUSY vacua. We show that under general assumptions all gauge nonsinglet fields, parameterizing flat directions (and in particular squarks and sleptons), get large $radiative$ masses which are related to the value of the Hubble constant ($H$) and to the expectation valu

Fu-guang Cao, Tao Huang, Chuan-wang Luo

The perturbative pion form factor with Sudakov suppression is re-examined. Taking into account the multi-gluon exchange in the law $Q^2$ regions, we suggest that the running coupling constant should be frozen at $α_s(t=\sqrt{<{\bf k}_{T}^{2}>})$ and $\sqrt{<{\bf k}_{T}^{2}>}$ is the average transverse momentum which can be determined by the pionic wave funct

A. Brandenburg, L. Dixon, Y. Shadmi

We discuss hard rescattering effects that can be measured using CP-even, T$_{\rm N}$-odd triple-product observables in polarized $Z$ decays to three jets. We show that the standard model contributions, from both QCD and electroweak rescattering, are very small. Thus these measurements are potentially sensitive to physics beyond the standard model. We investi

E. Papageorgiu

We reexamine the prospects of searching for a neutral Higgs boson in the intermediate-mass range, using the proton- and ion-beam facilities of the LHC to study coherent two-photon processes. Considering realistic design luminosities for the different ion beams, we find that beams of light-to-medium size ions like calcium will give the highest production rate

Xiao-Gang He

In this talk I discuss CP violation in hyperon decays in Left-Right symmetric models. I show that the asymmetry in polarization in $Λ\to pπ^-$ can be as large as $6\times 10^{-4}$ in these models, which is an order of magnitude larger than the Standard Model prediction.

F. Abe

This paper presents the first direct measurement of the $B$ meson differential cross section, $dσ/dp_T$, in $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$^{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully re

B. Jancovici

From the laws of macroscopic electrostatics of conductors (in particular the existence of screening) taken for granted, one can deduce universal properties for the thermal fluctuations in a classical Coulomb system at equilibrium. The universality is especially apparent in the long-range correlations of the electrical potentials and fields. The charge fluctu

B. Jancovici, G. Tellez

The grand potential of a classical Coulomb system has universal finite-size corrections similar to the ones which occur in the free energy of a simple critical system : the massless Gaussian field. Here, the Coulomb system is assumed to be confined by walls made of an ideal conductor material; this choice corresponds to simple (Dirichlet) boundary conditions

J. A. Sauls

I present a Ginzburg-Landau theory for hexagonal oscillations of the upper critical field of UPt$_3$ near $T_c$. The model is based on a $2D$ representation for the superconducting order parameter, $\vecη=(η_1,η_2)$, coupled to an in-plane AFM order parameter, $\vec{m}_s$. Hexagonal anisotropy of $H_{c2}$ arises from the weak in-plane anisotropy energy of th

S. Ambrosanio, B. Mele

A thorough study is performed on pair production and signatures of supersymmetric neutralinos in the MSSM at LEP2. Particular attention is paid to the region of the SuSy parameter space where the associated production of lightest and next-to-lightest neutralinos is the only visible allowed supersymmetric process. In that region, the signal is critically depe

Masato Jimbo, Tadashi Kon, Minami-Tateya collaboration

We have constructed a system for the automatic computation of cross-sections for the processes of the SUSY QED by the extension of the GRACE system including a Majorana fermion. The system has also been applied to another model including Majorana fermions, MSSM, by the definition of the model file.