January 1994 arXiv papers — page 2

N. G. Deshpande, Xiao-Gang He, S. Pakvasa

We consider the gluon dipole penguin operator contributions to $ε'/ε$ and CP violation in hyperon decays. It has been proposed by Bertolini et al. that the contribution to $ε'/ε$ may be significant. We show that there is a cancellation in the leading order contribution and this contribution is actually suppressed by a factor of order O($m_π^2, m_K^2)

Julie D. Blum

A supersymmetric collective coordinate expansion of the monopole solution of $N=4$ Yang-Mills theory is performed resulting in an $N=4$ supersymmetric quantum mechanics on the moduli space of monopole solutions.

D. M. Gitman, A. E. Gonçalves, I. V. Tyutin

A consistent procedure of canonical quantization of pseudoclassical model for spin one relativistic particle is considered. Two approaches to treat the quantization for the massless case are discussed, the limit of the massive case and independent quantization of a modified action. Quantum mechanics constructed for the massive case proves to be equivalent to

V. S. Dotsenko, G. Harris, E. Marinari, E. Martinec

We examine the geometrical and topological properties of surfaces surrounding clusters in the 3--$d$ Ising model. For geometrical clusters at the percolation temperature and Fortuin--Kasteleyn clusters at $T_c$, the number of surfaces of genus $g$ and area $A$ behaves as $A^{x(g)}e^{-μ(g)A}$, with $x$ approximately linear in $g$ and $μ$ constant. We observe

V. Bardek, S. Meljanac, A. Perica

We consider the generalized momentum-depending quon algebra in a dynamically evolving curved spacetime and perform a type of analysis similar to that of J.W.Goodison and D.J.Toms. We find that, at least in principle, all kinds of statistics may occur in some regions, i.e. phases in momentum space, depending on Bogoliubov coefficients determined by a specific

Paul F. Mende

When high energy strings scatter at fixed angle, their amplitudes characteristically fall off exponentially with energy, ${\cal A} \sim \exp(-s \times const.)$. We show that in a compact space this suppression disappears for certain kinematic configurations. Amplitudes are power-law behaved and therefore greatly enhanced. In spacetime this corresponds to fix

D. Kabat, M. J. Strassler

For an arbitrary quantum field in flat space with a planar boundary, an entropy of entanglement, associated with correlations across the boundary, is present when the field is in its vacuum state. The vacuum state of the same quantum field appears thermal in Rindler space, with an associated thermal entropy. We show that the density matrices describing the t

Kyung-Hyun Cho, Chaiho Rim

We present the anyon equation on a cylinder and in an infinite potential wall from the abelian Chern-Simons theory coupled to non-relativistic matter field by obtaining the effective hamiltonian through the canonical transformation method used for the theory on a plane and on a torus. We also give the periodic property of the theory on the cylinder.

A. Mishra, H. Mishra, P. K. Panda, S. P. Misra

We consider here quark matter equation of state including strange quarks and taking into account a nontrivial vacuum structure for QCD with gluon condensates. The parameters of condendsate function are determined from minimisation of the thermodynamic potential. The scale parameter of the gluon condensates is fixed from the SVZ parameter in the context of QC

G. Dvali, Q. Shafi

We explore the gauge hierarchy problem within the framework of supersymmetric $SU(3)_c \times SU(3)_L \times SU(3)_R$ with a minimal set of higgs supermultiplets. Imposition of a suitable discrete (alternatively $R$) symmetry `prevents' the electroweak higgs doublets from becoming superheavy through renormalizable couplings. A full resolution of the prob

B. Masud

In the paper is presented a four-body potential model for $q^2\bar{q}^2$ systems which includes both the spin and flavour degrees of freedom, extending the formalism presented already in the spin independent situation. This allows an application to a realistic situation, which is chosen to be $K\bar{K}$ scattering. It is seen that because of the gluonic effe

C. P. Burgess, J. M. Cline

Double-beta decay experiments have been traditionally interpreted in terms of the Gelmini-Roncadelli triplet majoron model, which has been ruled out by LEP. We briefly survey here the kinds of physics to which these experiments might be sensitive in the light of the LEP constraints. We identify six broad categories of models, including some new categories wh

R. Kleiss, H. Burkhardt

A fast and simple Monte Carlo program is presented that simulates single Bremsstrahlung in Bhabha scattering, e+e- --> e+e-gamma, without constraints on scattering angles. This allows the study of this process at arbitrarily small, or even vanishing, scattering angles. Experimental cuts can be imposed on an event-by-event basis, allowing for detailed studies

N. Haba, C. Hattori, M. Matsuda, T. Matsuoka

In a certain type of Calabi-Yau superstring models it is clarified that the symmetry breaking occurs by stages at two large intermediate energy scales and that two large intermediate scales induce large Majorana-masses of right-handed neutrinos. Peculiar structure of the effective nonrenormalizable interactions is crucial in the models. In this scheme Majora

Tkemi Hayashi, Yoshio Koide, Masahisa Matsuda, Morimitsu Tanimoto

We study the effect of the "chromo-electric" dipole moment on the electric dipole moment(EDM) of the neutron in the two Higgs doublet model. We systematically investigate the Weinberg's operator $O_{3g}=GG\t G$ and the operator $O_{qg}=\bar qσ\t Gq$, in the cases of $\tan\b\gg 1$, $\tan\b\ll 1$ and $\tan\b\simeq 1$. It is shown that $O_{sg}$ give

M. Baig, J. B. Kogut

In this talk we present some recent and new results on the phase structure and the continuum limit of lattice formulation of pure gauge QED coupled to Higgs fields. We show the presence of second order phase transition lines allowing for a continuum limit. Nevertheless, finite size analysis shows that this theory is logarithmically trivial. The role of magne

Y. Iwasaki

Parallel computers dedicated to lattice field theories are reviewed with emphasis on the three recent projects, the Teraflops project in the US, the CP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new commercial parallel computers are also discussed. Recent development of semiconductor technologies is briefly surveyed in relation to po

Milan Mijic

It is shown how coarse-graining of quantum field ^M theory in de Sitter space leads to the emergence of a classical ^M stochastic description as an effective theory in the infra-red regime. ^M The quantum state of the coarse-grained scalar field is found to be a highly^M squeezed coherent state, whose center performs a random walk on a^M bundle of classical

Hao Li, Thomas C. Halsey, Alexander Lobkovsky

Beyond a threshold, electric or magnetic fields cause a dielectric or ferromagnetic fluid drop respectively to develop conical tips. We analyze the appearance of the conical tips and the associated shape transition of the drop using a local force balance as well as a global energy argument. We find that a conical interface is possible only when the dielectri

Jose A. Riera, Elbio Dagotto

The optical conductivity, $σ(ω)$, of the two dimensional one-band Hubbard model is calculated at finite temperature using exact diagonalization techniques on finite clusters. The in-plane d.c. resistivity, $ρ_{ab}$, is also evaluated. We find that at large U/t and temperature T, $ρ_{ab}$ is approximately linear with temperature, in reasonable agreement with

G. M. Zhang, Z. B. Su, L. Yu

An asymptotically exact partition function of the multi-channel resonant-level model is obtained through Tomonaga-Luttinger bosonization. A Fermi-liquid vs non-Fermi-liquid transition, resulting from a competition between the Kondo and X-ray edge physics, is elucidated explicitly via the renormalization group theory. In the strong-coupling limit, the model i

B. Huckestein, L. Schweitzer

We study the time evolution of wavepackets of non-interacting electrons in a two-dimensional disordered system in strong magnetic field. For wavepackets built from states near the metal-insulator transition in the center of the lowest Landau band we find that the return probability to the origin $p(t)$ decays algebraically, $p(t) \sim t^{-D_2/2}$, with a non

F. Guinea, E. Louis, J. A. Verges

The applicability of the Hartree-Fock and random phase approximations to models of strongly correlated electrons is discussed. The 2D Hubbard model is analyzed. An antiferromagnetic phase (at half filling) and Fermi liquid behavior (at low electron densities) are found. In addition, the system shows an unconventional regime near half filling. It is character

Serge Yu. Potapenko

The step motions considered are those in which crystallization is controlled by a single diffusion process, either the substance diffusion for growth from solution or the flow of latent heat from the step for growth from melt. Quasi-static diffusion nearby two parallel steps and nearby a train of parallel steps is considered. Terraces and step risers are ass

Xiaowen Shan, Hudong Chen

We describe in detail a recently proposed lattice-Boltzmann model for simulating flows with multiple phases and components. In particular, the focus is on the modeling of one-component fluid systems which obey non-ideal gas equations of state and can undergo a liquid-gas type phase transition. The model is shown to be momentum-conserving. From the microscopi

Steven B. Bradlow, Oscar Garcia-Prada

This is a resubmission of preprint 9401008 , which has some TeXnical errors introduced by the "reform" procedure (designed to avoid precisely these problems!). The original can be formatted by editing out the messages "%% following line cannot be broken..." at line 1674. This problem has been corrected in the current version. The content of t

Stanley J. Brodsky, Matthias Burkardt, Ivan Schmidt

We develop simple analytic representations of the polarized quark and gluon distributions in the nucleon at low $Q^2$ which incorporate general constraints obtained from the requirements of color coherence of gluon couplings at $x \sim 0$ and the helicity retention properties of perturbative QCD couplings at $x \sim 1.$ The unpolarized predictions are simila

Kenneth Lane

In these lectures we present the motivation for dynamical electroweak symmetry breaking and its most popular realization, technicolor. We introduce the basic ideas of technicolor and its companion theory of flavor, extended technicolor. We review the classical theory of technicolor, based on naive scaling from quantum chromodynamics, and discuss the classica

Kikuo Harigaya, Shuji Abe

Effects of Coulomb interactions and lattice fluctuations in the optical absorption spectra of C60 and C70 are theoretically investigated by using a tight binding model with long-range Coulomb interaction and bond disorder. Anisotropy effects in C70 are also considered. Optical spectra are calculated by using the Hartree-Fock approximation followed by the con

Yusuke Kato, Akihiro Tanaka

We study the $S=1$ quantum spin chain with bond alternation ${\cal H}=\sum _i (1-(-1)^iδ)\vect{S}_i\cdot \vect{S}_{i+1}$ by the density matrix renormalization group method recently proposed by Steven R. White (\PRL{69}{3844}{1993}). We find a massless point at $δ_c =0.25 \pm 0.01$. We also find the edge states in the region $δ<δ_c$ under the open boundary co

Patrick McGraw

It is shown that a model with a spontaneously broken global symmetry can support defects analogous to Alice strings, and a process analogous to Cheshire charge exchange can take place. A possible realization in superfluid He-3 is pointed out.

I. Merola, O. Ragnisco, Tu Gui Zhang

In the framework of the reduction technique for Poisson-Nijenhuis structures, we derive a new hierarchy of integrable lattice, whose continuum limit is the AKNS hierarchy. In contrast with other differential-difference versions of the AKNS system, our hierarchy is endowed with a canonical Poisson structure and, moreover, it admits a vector generalisation. We

A. V. Yung

The topological sigma model with the semi-infinite cigar-like target space (black hole geometry) is considered. The model is shown to possess unsuppressed instantons. The noncompactness of the moduli space of these instantons is responsible for an unusual physics. There is a stable vacuum state in which the vacuum energy is zero, correlation functions are nu

M. V. Cougo-Pinto, C. Farina, A. J. Segui-Santonja

We apply to the massive scalar field a method recently proposed by Schwinger to calculate the Casimir effect. The method is applied with two different regularization schemes: the Schwinger original one by means of Poisson formula and another one by means of analytical continuation.

W. Lerche

(Talk given at Strings &#39;93, Berkeley, and at XXVII. Internationales Symposium über Elementarteilchentheorie, Wendisch-Rietz, 1993) We review the superconformal properties of matter coupled to $2d$ gravity, and $W$-extensions thereof. We show in particular how the \nex2 structure provides a direct link between certain matter-gravity systems and matrix mod

Debajyoti Choudhury, Raj Gandhi, J. A. Gracey, Biswarup Mukhopadhyaya

The addition of $m$ singlet right-handed neutrinos to the Standard Model leads to radiatively generated mass corrections for the $SU(2)_L $ doublet neutrinos. For those neutrinos which are massless at the tree level after this addition, this implies a small mass generated at the two-loop level via $W^{\pm}$ exchange. We calculate these mass corrections exact

Mohammad R. Ahmady, Roberto R. Mendel

The decay rates for the exclusive B decays $B \rightarrow K η_c $ and $B \rightarrow K^* η_c$ are calculated in the context of the heavy quark effective theory. We obtain $Γ(B \rightarrow K η_c )/Γ(B\rightarrow Kψ)=1.6 \pm 0.2$ and $Γ(B\rightarrow K^*η_c)/Γ(B \rightarrow K^*ψ)=0.39 \pm 0.04$. These results lead to estimates $BR(B \rightarrow K η_c)=(0.11 \pm

Z. Li, M. Guidry, T. Barnes, E. S. Swanson

We extend the quark Born diagram formalism for hadron-hadron scattering to processes with valence $q\bar q$ annihilation, specifically $I=0$ and $I=1$ $ππ$ and $I=1/2$ $Kπ$ elastic scattering. This involves the $s$-channel hybrid annihilation process $q^2\bar q^2 \to q\bar q g \to q^2\bar q^2$ and conventional $s$-channel $q\bar q$ resonances, in addition to

J. Lopez, D. Nanopoulos, G. Park, X. Wang

We study various aspects of $SU(5)\times U(1)$ supergravity as they relate to the experimental verification or falsification of this model. We consider two string-inspired, universal, one-parameter, no-scale soft-supersymmetry-breaking scenarios, driven by the $F$-terms of the moduli and dilaton fields. The model is described in terms of the supersymmetry ma

Jean-Paul Blaizot, Edmond Iancu

We present new, non-abelian, solutions to the equations of motion which describe the collective excitations of a quark-gluon plasma at high temperature. These solutions correspond to longitudinal and transverse plane-waves propagating through the plasma.

Jacques Goldberg

Uniform random numbers, not Gaussian random numbers, should have been used with Standard Solar Models to estimate the effect on the neutrino flux of uncertainties in input data. The observed discrepancy is therefore probably quite smaller than currently accepted.

T. Hatsuda

A brief review on the recent theoretical progress in hot/dense QCD is given. Special emphasis is put on the non-perturbative aspects of QCD plasma and the modification of hadron proporties near the critical temperature of chiral transition.

Yu. A. Simonov

Confining configurations are introduced into the standard instanton vacuum model. This drastically improves theoretical properties of the vacuum: instanton size density $d(ρ)$ stabilizes at $ρ\sim 0.2 fm$, all chiral effects are formulated in a gauge-invariant way and quarks are confined. An interesting interplay of chiral and confining dynamics is observed;

Thomas G. Rizzo

Recent results from the CLEO Collaboration on both inclusive and exclusive radiative $B$ decays are used to constrain the parameter space of two versions of the Left-Right Symmetric Model. In the first scenario, when the left- and right-handed Cabibbo-Kobayashi-Maskawa mixing matrices are equal, $V_L=V_R$, the radiative $B$ decay data is shown to lead to str

Paolo Rossi, Ettore Vicari

Analytical and numerical methods are applied to principal chiral models on a two-dimensional lattice and their predictions are tested and compared. New techniques for the strong coupling expansion of SU(N) models are developed and applied to the evaluation of the two-point correlation function. The momentum-space lattice propagator is constructed with precis

Biplab Bhawal, Vijay Chickarmane

We calculate the response of an ideal Michelson interferometer incorporating both dual recycling and squeezed light to gravitational waves. The photon counting noise has contributions from the light which is sent in through the input ports as well as the vacuum modes at sideband frequencies generated by the gravitational waves. The minimum detectable gravity

R. J. Henderson, S. G. Rajeev

We study a model for quantum gravity on a circle in which the notion of a classical metric tensor is replaced by a quantum metric with an inhomogeneous transformation law under diffeomorphisms. This transformation law corresponds to the co--adjoint action of the Virasoro algebra, and resembles that of the connection in Yang--Mills theory. The transformation

Subenoy Chakraborty, Peter Peldan

We introduce a gauge and diffeomorphism invariant theory on Yang-Mills phase space. The theory is well defined for an arbitrary gauge group with an invariant bilinear form, it contains only first class constraints, and the spacetime metric has a simple form in terms of the phase space variables. With gauge group $SO(3,C)$, the theory equals the Ashtekar form

Michele Maggiore

We propose a quantum description of black holes. The degrees of freedom to be quantized are identified with the microscopic degrees of freedom of the horizon, and their dynamics is governed by the action of the relatistic bosonic membrane in $D=4$. We find that a consistent and plausible description emerges, both at the classical and at the quantum level. We

M. Gasperini

We discuss bounds on the dilaton mass, following from the cosmological amplification of the quantum fluctuations of the dilaton background, under the assumption that such fluctuations are dominant with respect to the classical background oscillations. We show that if the fluctuation spectrum grows with the frequency the bounds are relaxed with respect to the

Norman Cruz, Cristián Martínez, Leda Peña

Null and timelike geodesics around a 2+1 black hole are determined. Complete geodesics of both types exist in the rotating black-hole background, but not in the spinless case. Upper and lower bounds for the radial size of the orbits are given in all cases and the possibility of passing from one black hole exterior spacetime to another is discussed using the

João P. Abreu, Paulo Crawford, José P. Mimoso

New exact solutions of Einstein&#39;s gravity coupled to a self-interacting conformal scalar field are derived in this work. Our approach extends a solution-generating technique originally introduced by Bekenstein for massless conformal scalar fields. Solutions are obtained for a Friedmann-Robertson-Walker geometry both for the cases of zero and non-zero cur

A. Belić, F. Dalfovo, S. Fantoni, S. Stringari

Variational Monte Carlo method is used to calculate ground state properties of $^4$He droplets, containing 70, 112, 168, 240, 330, and 728 particles. The resulting particle and kinetic energy densities are used as an input in the Feynman-Lekner theory for $^3$He impurities. The kinetic energy density of $^4$He atoms and the energy of the $^3$He surface state

Zoltan Neda

High-accuracy Swendsen and Wang Monte Carlo simulations were performed to study the Curie temperature of ferromagnetic, binary Ising systems on the square lattice. Our results are compared with mean-field like approaches. Based on these former theories, we give a new formula to estimate the Curie temperature of the system.

Roger W. Romani, I. -A. Yadigaroglu

There are now a half dozen young pulsars detected in high energy photons by the Compton GRO, showing a variety of emission efficiencies and pulse profiles. We present here a calculation of the pattern of high energy emission on the sky in a model which posits $γ$-ray production by charge depleted gaps in the outer magnetosphere. This model accounts for the r

Arnon Dar, Giora Shaviv

An imroved standard solar model, with more accurate input parameters and more accurate treatment of plasma physics effects, predicts a solar neutrino flux which is consistent within experimental uncertainties with the solar neutrino observations after 1986.

Paolo Aluffi

Given a graph G (or more generally a matroid embedded in a projective space), we construct a sequence of varieties whose geometry encodes combinatorial information about G. For example, the chromatic polynomial of G (giving at each m>0 the number of colorings of G with m colors, such that no adjacent vertices are assigned the same color) can be computed as a

M. Dubois-Violette, P. W. Michor

There is a canonical mapping from the space of sections of the bundle $\wedge T^\ast M\otimes ST\ M$ to $Ω(T^\ast M ; T(T^\ast M))$. It is shown that this is a homomorphism on $Ω(M;TM) for the Frölicher-Nijenhuis brackets, and also on $Γ(ST\ M)$ for the Schouten bracket of symmetric multi vector fields. But the whole image is not a subalgebra for the Frölich

S. Yu. Khlebnikov

Semiclassical transition probabilities characterize transfer of energy between &#34;hard&#34; and &#34;soft&#34; modes in various physical systems. We establish the boundary problem for singular euclidean solutions used to calculate such probabilities. Solutions are found numerically for a system of two interacting quartic oscillators. In the double-well cas

M. R. Ahmady, R. R. Mendel

We use a simple perturbation theory argument and measurements of charmonium leptonic widths $Γ(ψ_{NS} \rightarrow e^+e^-)$ to estimate the ratio \mbox{$R_\circ \equiv {\vert Ψ_{η_{c1S}}(0) \vert}^2 /{\vertΨ_{ψ_{1 S}}(0)\vert}^2$} in the general context of non- relativistic potential models. We obtain $R_\circ = 1.4 \pm 0.1$. We then apply well known potentia

Juan Garcia-Bellido

We study stochastic inflation in the presence of a dynamical gravitational constant. We describe the Arnowitt--Deser--Misner formalism for Jordan--Brans--Dicke theory of gravity with an inflaton field. The inflaton and dilaton scalar fields can be separated into coarse-grained background fields and quantum fluctuations. We compute the amplitude of the pertur

Klaus Lang, Werner Ruehl

The distribution of quasiprimary fields of fixed classes characterized by their O$(N)$ representations $Y$ and the number $p$ of vector fields from which they are composed at $N=\infty$ in dependence on their normal dimension $[δ]$ is shown to obey a Hardy-Ramanujan law at leading order in a $\frac{1}{N}$-expansion. We develop a method of collective fusion o

Eduard Looijenga

This replacement corrects statement and proof of the main result. Also, a section on the universal Abel-Jacobi map has been added.

A. González-Ruiz

We consider integrable open--boundary conditions for the supersymmetric t--J model commuting with the number operator $n$ and $S^{z}$. Four families, each one depending on two arbitrary parameters, are found. We find the relation between Sklyanin&#39;s method of constructing open boundary conditions and the one for the quantum group invariant case based on M

Chanju Kim, Yoonbai Kim

The Abelian Higgs model with or without external particles is considered in curved space. Using the dual transformation, we rewrite the model in terms of dual gauge fields and derive the Bogomol&#39;nyi-type bound. We examine cylindrically symmetric solutions to Einstein equations and the first-order Bogomol&#39;nyi equations, and find vortex solutions and v

Angel Sanchez, A R Bishop, Francisco Dominguez-Adame

We have examined the dynamical behavior of the kink solutions of the one-dimensional sine-Gordon equation in the presence of a spatially periodic parametric perturbation. Our study clarifies and extends the currently available knowledge on this and related nonlinear problems in four directions. First, we present the results of a numerical simulation program

David Raitt, Hermann Riecke

Domain walls between spatially periodic patterns with different wave numbers, can arise in pattern-forming systems with a neutral curve that has a double minimum. Within the framework of the phase equation, the interaction of such walls is purely attractive. Thus, they annihilate each other and, if the total phase is not conserved, the final state will be pe

S. J. Lee, A. Z. Mekjian

Various features of the charge yield in heavy ion collisions are studied. Considered here are the nuclear emulsion data of $^{84}$Kr, $^{131}$Xe, $^{197}$Au, $^{238}$U in the energy range of 1 GeV/A. Mean charge yields and multiplicity distribution of these data indicate that the nuclear fragmentation at this energy is a multiprocess phenomena. Power moments

M. K. Liou, R. Timmermans, B. F. Gibson

A novel soft-photon amplitude is proposed to replace the conventional Low soft-photon amplitude for nucleon-nucleon bremsstrahlung. Its derivation is guided by the standard meson-exchange model of the nucleon-nucleon interaction. This new amplitude provides a superior description of $ppγ$ data. The predictions of this new amplitude are in close agreement wit

Yi-Zhi Huang, James Lepowsky

We introduce the main concepts and announce the main results in a theory of tensor products for module categories for a vertex operator algebra. This theory is being developed in a series of papers including hep-th 9309076 and hep-th 9309159. The theory applies in particular to any ``rational&#39;&#39; vertex operator algebra for which products of intertwini

E. Billey, J. Avan, O. Babelon

We compute the $r$-matrix for the elliptic Euler-Calogero-Moser model. In the trigonometric limit we show that the model possesses an exact Yangian symmetry.

S. G. Rajeev

A nonlocal and nonlinear theory of hadrons, equivalent to the color singlet sector two dimensional QCD, is constructed. The phase space space of this theory is an infinite dimensional Grassmannian. The baryon number of QCD corresponds to a topological invariant (`virtual rank&#39;) of the Grassmannian. It is shown that the hadron theory has topological solit

Tom H. Koornwinder

A tutorial introduction is given to general Hopf algebras and to general compact quantum groups. In the definition and further treatment of compact quantum groups C*-algebras are avoided. Contact with Woronowicz&#39;s compact matrix quantum groups is made at a later stage.

H. Heiselberg

In weakly interacting quark-gluon plasmas diffusion of color is found to be much slower than the diffusion of spin and flavor because color is easily exchanged by the gluons in the very singular forward scattering processes. If the infrared divergence is cut off by a magnetic mass, $m_{mag}\sim α_sT$, the color diffusion is $D_{color}\sim (α_s\ln(1/α_s)T)^{-

Kingman Cheung

We present the photoproduction of an intermediate mass Higgs (IMH) boson associated with a $W$ boson at the future electron-proton colliders using bremsstrahlung photon beam or laser backscattered photon beam. With bremsstrahlung photon beam the search for the IMH boson is unfavorable because of the small signal rate. But with laser photon beam the search is

B. Badelek, J. Kwiecinski

The quantity $2F_2^d(x,Q^2)/F_2^p(x,Q^2)-1$ is calculated in the region of low $x$ and low- and moderate $Q^2$ relevant for recent NMC and E665 measurements as well as for the expected final results of the precise NMC analysis of their low $x$ data. The calculations include nuclear shadowing effects and a suitable extrapolation of the structure functions of

G. Bimonte, G. Lozano

We analyze the existence of string-like defects in a two-Higgs-doublet system having $SU(2) \times U(1)_Y \times U(1)_{Y^{\prime}}$ as gauge group. We are able to show that, when certain relations among the parameters hold, these configurations satisfy a set of first order differential equations (Bogomol&#39;nyi equations) and their energy is proportional to

N. N. Nikolaev, B. G. Zakharov

The Balitskii-Fadin-Kuraev-Lipatov (BFKL) and the Gribov-Lipatov- Dokshitzer-Altarelli-Parisi (GLDAP) evolution equations for the diffractive deep inelastic scattering at ${1\over x} \gg 1$ are shown to have a common solution in the weak coupling limit: $F_{2}(x,Q^{2})\propto [α_{S}(Q^{2})]^{-γ} \left({1\over x}\right)^{Δ_{\Pom}}$. The exponent $γ$ and the p

J. Ambjorn, K. Farakos, S. Hands, G. Koutsoumbas

We study the spectrum of the Dirac Hamiltonian in the presence of high temperature sphaleron-like fluctuations of the electroweak gauge and Higgs fields, relevant for the conditions prevailing in the early universe. The fluctuations are created by numerical lattice simulations. It is shown that a change in Chern-Simons number by one unit is accompanied by ei

M. N. Chernodub, M. I. Polikarpov, M. A. Zubkov

We show that in general abelian projection of lattice gluodynamics it is not only monopoles but also strings are present. Both these topological excitations may be responsible for the confinement of color. We illustrate our ideas by some explicit results in the Abelian Higgs model with the Villain action.

Michael Fowler

Talk presented at NATO Gran Finale Conference, Como, Italy, September 1993

Hirokazu Tsunetsugu, Matthias Troyer, T. Maurice Rice

Exact diagonalization studies for a doped t-J ladder (or double chain) show hole pairing in the ground state. The excitation spectrum separates into a limited number of quasiparticles which carry charge $+|e|$ and spin ${1 \over 2}$ and a triplet mode. At half-filling the former vanish but the latter evolves continuously into the triplet band of the spin liq

N. R. Cooper, J. T. Chalker

We present an interpretation of recent cyclotron resonance experiments on the two-dimensional electron gas in GaAs/AlGaAs heterostructures. We show that the observed dependence of the resonance spectrum on Landau level occupancy and temperature arises from the interplay of three factors: spin-splitting of the cyclotron frequency; thermal population of the tw

Gabriele Ghisellini, Francesco Haardt, Giorgio Matt

The presence of an obscuring torus around the nucleus of Seyfert galaxies, as supposed in the popular unification scheme, can strongly modify the X--ray spectrum for both type 1 and 2 Seyfert galaxies. We find that if the torus is Compton thick, it can scatter at small angles a significant fraction of the nuclear radiation, and contribute to the continuum of

D. Tytler, X. -M. Fan

Recently Lu presented tentative evidence for C IV lines in QSO Lyman-alpha forest systems with strong lines. We have performed a similar search for C IV in our 10 km/sec echelle spectra of the bright QSO HS~1946+7658. We shifted the spectra to align the expected positions of the C IV lines in 65 Lyman-alpha systems, then added them. The resulting composite s

A. C. Robin

Models of population synthesis for the Galaxy have been developed in order to understand galactic structure and evolution. They allow to test scenarii of evolution by comparisons between model predictions and observed distributions. Forthcoming near-infrared surveys will enormously increase the amount of information about the distributions of late type stars

Shahn Majid

We study the quantum matrix algebra $R_{21}x_1x_2=x_2x_1 R$ and for the standard $2\times 2$ case propose it for the co-ordinates of $q$-deformed Euclidean space. The algebra in this simplest case is isomorphic to the usual quantum matrices $M_q(2)$ but in a form which is naturally covariant under the Euclidean rotations $SU_q(2)\otimes SU_q(2)$. We also int

Yuval Grossman

We study the most general Multi-Higgs-Doublet Model (MHDM) with Natural Flavor Conservation (NFC). The couplings of a charged scalar $H_i^{\pm}$ to up quarks, down quarks and charged leptons depend on three new complex parameters, $X_i$, $Y_i$ and $Z_i$, respectively. We prove relations among these parameters. We carry out a comprehensive analysis of phenome

T. Hatsuda, T. Kunihiro

We review the Nambu-Jona-Lasinio (NJL) approach to the dynamical breaking of chiral symmetry in Quantum Chromodynamics (QCD). The subjects treated in Part I include the vacuum structure of QCD, mass spectra and coupling constants of hadrons, flavor mixing in mesons, the violation of the OZI rule in baryons, and the validity of the chiral perturbation in QCD.

Peter Nielaba, Vladimir Privman

Models of irreversible surface deposition of k-mers on a linear lattice, with screening suppressed by disallowing overhangs blocking large gaps, are studied by extensive Monte Carlo simulations of the temporal and size dependence of the growing interface width. Despite earlier finding that for such models the deposit density tends to increase away from the s

Tanmay Vachaspati

The scenario of a cosmology with topological defects is surveyed starting from the field theoretic aspects and ending with a description of large-scale structure formation and magnetic field generation. (Lectures delivered at ICTP, Trieste, July 1993.)

S. Torres

After the detection of structure in the microwave sky, the characterization of the observed features may be a useful guide to current and future experiments. The first year COBE-DMR sky maps were analyzed in order to identify the most significant hot and cold spots. The statistical significance of potential spots of cosmic origin was evaluated with Monte Car

H. Heiselberg

The quark and gluon viscosities are calculated in quark-gluon plasmas to leading orders in the coupling constant by including screening. For weakly interaction QCD and QED plasmas dynamical screening of transverse interactions and Debye screening of longitudinal interactions controls the infrared divergences. For strongly interacting plasmas other screening

E. Pallante, R. Petronzio

We construct an effective Lagrangian for low energy hadronic interactions through an infinite expansion in inverse powers of the low energy cutoff $Λ_χ$ of all possible chiral invariant non-renormalizable interactions between quarks and mesons degrees of freedom. We restrict our analysis to the leading terms in the $1/N_c$ expansion. The effective expansion

Gábor Vattay, Andreas Wirzba, Per E. Rosenqvist

An extension of the Gutzwiller trace formula is given that includes diffraction effects due to hard wall scatterers or other singularities. The new trace formula involves periodic orbits which have arcs on the surface of singularity and which correspond to creping waves. A new family of resonances in the two disk scattering system can be well described which

Benjamin Grinstein, Paul F. Mende

It is shown that the form factors in the semileptonic decay of ground state heavy mesons to light pseudoscalar mesons are dominated by the vector meson pole at all momentum transfers. First, the general approaches to modeling form factors in terms of quark model, pole dominance, or hybrid shapes are reviewed. It is then shown that in the combined limits of h

C. J. Benesh

A simple, new method for solving for the $Q^2$ evolution of parton distributions in perturbative QCD using cubic splines is described and applied to the evolution of nonsinglet quark distributions.

Walter Van Assche

The weak convergence of orthogonal polynomials is given under conditions on the asymptotic behaviour of the coefficients in the three-term recurrence relation. The results generalize known results and are applied to several systems of orthogonal polynomials, including orthogonal polynomials on a finite set of points.

A. I. Aptekarev, Valeri\uı A. Kaliaguine, Walter Van Assche

We study nonsymmetric tridiagonal operators acting in the Hilbert space $\ell^2$ and describe the spectrum and the resolvent set of such operators in terms of a continued fraction related to the resolvent. In this way we establish a connection between Padé approximants and spectral properties of nonsymmetric tridiagonal operators.

Steven L. Carbon, Charles B. Thorn

High energy string scattering at fixed momentum transfer, known to be dominated by Regge trajectory exchange, is interpreted by identifying families of string states which induce each type of trajectory exchange. These include the usual leading trajectory $\alpha(t)=\alpha^\prime t+1$ and its daughters as well as the ``sister'' trajectories $\alpha_m(t)=\alp