February 1996 arXiv papers — page 6

Emili Bagan, Martin Lavelle, David McMullan

We investigate the properties of a dressed electron which reduces, in a particular class of gauges, to the usual fermion. A one loop calculation of the propagator is presented. We show explicitly that an infra-red finite, multiplicative, mass shell renormalisation is possible for this dressed electron, or, equivalently, for the usual fermion in the abovement

Frank Ferrari, Adel Bilal

We carefully study the global structure of the solution of the $N=2$ supersymmetric pure Yang-Mills theory with gauge group $SU(2)$ obtained by Seiberg and Witten. We exploit its ${\bf Z}_2$-symmetry and describe the curve in moduli space where BPS states can become unstable, separating the strong-coupling from the weak-coupling region. This allows us to obt

Rubén A. Pasmanter

An intrinsic metric tensor, a flat connexion and the corresponding distance-like function are constructed in the configuration space formed by velocity field {\bf and} the thermodynamic variables of an inviscid fluid. The kinetic-energy norm is obtained as a limiting case; all physical quantities are Galilean invariant. Explicit expressions are given for the

Kazuo Fujikawa

A path integral evaluation of the Green's function for the hydrogen atom initiated by Duru and Kleinert is studied by recognizing it as a special case of the general treatment of the separable Hamiltonian of Liouville-type. The basic dynamical principle involved is identified as the Jacobi's principle of least action for given energy which is reparam

Norbert Schultka, Efstratios Manousakis

We study scaling of the superfluid density with respect to the film thickness by simulating the $x-y$ model on films of size $L \times L \times H$ ($L >> H$) using the cluster Monte Carlo. While periodic boundary conditions where used in the planar ($L$) directions, Dirichlet boundary conditions where used along the film thickness. We find that our results c

N. C. Tsamis, R. P. Woodard

We consider the quantum gravitational back-reaction on an initially inflating, homogeneous and isotropic universe whose topology is $T^3 \times \Re$. Although there is no secular effect at one loop, an explicit calculation shows that two-loop processes act to slow the rate of expansion by an amount which becomes non-perturbatively large at late times. By exp

N. C. Tsamis, R. P. Woodard

The graviton tadpole has recently been computed at two loops in a locally de Sitter background. We apply intermediate results of this work to exhibit the graviton self-energy at one loop. This quantity is interesting both to check the accuracy of the first calculation and to understand the relaxation effect it reveals. In the former context we show that the

N. C. Tsamis, R. P. Woodard

We describe our recent calculation of two-loop corrections to the expansion rate of an initially inflating universe on the manifold $T^3 \times \Re$. If correct, our result proves that quantum gravitational effects slow the rate of inflation by an amount which becomes non-perturbatively large at late times. In a preliminary discussion of basic issues we show

Siye Wu

We extend the equivariant holomorphic Morse inequalities of circle actions to cases with torus and non-Abelian group actions on holomorphic vector bundles over Kahler manifolds and show the necessity of the Kahler condition. For torus actions, there is a set of inequalities for each choice of action chambers specifying directions in the Lie algebra of the to

Varghese Mathai, Siye Wu

Assume that the circle group acts holomorphically on a compact Kähler manifold with isolated fixed points and that the action can be lifted holomorphically to a holomorphic Hermitian vector bundle. We give a heat kernel proof of the equivariant holomorphic Morse inequalities. We use some techniques developed by Bismut and Lebeau. These inequalities, first ob

Michael B. Green, Michael Gutperle

The Born--Infeld-like effective world-volume theory of a single 3-brane is deduced from a manifestly space-time supersymmetric description of the corresponding $D$-brane. This is shown to be invariant under $SL(2,R)$ transformations that act on the abelian gauge field as well as the bulk fields. The effective theory of two nearby parallel three-branes involv

Ahmed Hindawi, Burt A. Ovrut, Daniel Waldram

We show how spontaneous supersymmetry breaking in the vacuum state of higher-derivative supergravity is transmitted, as explicit soft supersymmetry-breaking terms, to the effective Lagrangian of the standard electroweak model. The general structure of the soft supersymmetry breaking terms is presented and a new scenario for understanding the gauge hierarchy

D. Kharzeev

QCD as a gauge non-Abelian theory imposes severe constraints on the structure of the baryon wave function. We point out that, contrary to a widely accepted belief, the traces of baryon number in a high-energy process can reside in a non-perturbative configuration of gluon fields, rather than in the valence quarks. We argue that this conjecture can be tested

R. Martonak, E. Tosatti

In the context of perovskite quantum paraelectrics, we study the effects of a quadrupolar interaction $J_q$, in addition to the standard dipolar one $J_d$. We concentrate here on the nonlinear dielectric response $χ_{P}^{(3)}$, as the main response function sensitive to quadrupolar (in our case antiquadrupolar) interactions. We employ a 3D quantum four-state

Byunghan Kim

In this paper, we prove the number of countable models of a countable supersimple theory is either 1 or infinite. This result is an extension of Lachlan's theorem on a superstable theory.

Oren Kolman, Saharon Shelah

In the original version of this paper, we assume a theory $T$ that the logic $\mathbb L_{\kappa, \aleph_{0}}$ is categorical in a cardinal $\lambda > \kappa$, and $\kappa$ is a measurable cardinal. There we prove that the class of model of $T$ of cardinality $<\lambda$ (but $\geq |T|+\kappa$) has the amalgamation property; this is a step toward understanding

Achim Kempf

We continue studies on quantum field theories on noncommutative geometric spaces, focusing on classes of noncommutative geometries which imply ultraviolet and infrared modifications in the form of nonzero minimal uncertainties in positions and momenta. The case of the ultraviolet modified uncertainty relation which has appeared from string theory and quantum

Haralambos Marmanis

In this note, we propose an exegesis of the Maxwell equations for electromagnetism. We begin with an analogy between the homogeneous Maxwell equations and the equations needed to describe the vorticity field of an incompressible inviscid fluid. We suggest that the inhomogeneous equations are analogous to two equations valid in turbulent hydrodynamics. Once t

Evgeny A. Ivanov

We give a brief account of two recent applications of the harmonic superspace method: (i) an off-shell description of torsionful $(4,4)$ supersymmetric $2D$ sigma models in the framework of $SU(2)\times SU(2)$ harmonic superspace and (ii) the harmonic superspace formulation of ``small&#39;&#39; $N=4$ $SU(2)$ superconformal algebra and the related super KdV h

Hua Wang, Chong-Sheng Li, Hong-Yi Zhou, Yu-Ping Kuang

Supersymmetric QCD corrections to top quark pair production by photon fusion are calculated in the minimal supersymmetric standard model taking into account of the effects of stops in the corrections to the total cross-section of t anti-t production at the future electron-positron linear collider. We find that the relative correction can be a few percent for

P. Ball, V. M. Braun

We give a complete re-analysis of the leading twist quark-antiquark light-cone distribution amplitudes of longitudinal and transverse $ρ$ mesons. We derive Wandzura-Wilczek type relations between different distributions and update the coefficients in their conformal expansion using QCD sum rules including next-to-leading order radiative corrections. We find

S. Fajfer

The long distance contribution to $K^+ \to π^+ ν{\bar ν} $ is calculated using chiral perturbation theory. The leading contribution comes from $O(p^4)$ tree terms. The branching ratio of the $O(p^4)$ long distance contribution is found to be of order $10_{-3}$ smaller than the short distance contributions.

Leonid Frankfurt, Aharon Levy

We outline $QCD$ predictions for the diffractive electroproduction of heavy flavor vector mesons and compare them with available data.

J. Kwiecinski, A. D. Martin, P. J. Sutton

The BFKL and the unified angular-ordered equations are solved to determine the gluon distribution at small $x$. The impact of kinematic constraints is investigated. Predictions are made for observables sensitive to the gluon at small $x$. In particular comparison is made with measurements at the HERA electron-proton collider of the proton structure function

T. Morii, A. I. Titov, T. Yamanishi

It is shown that the parity--violating deep--inelastic scatterings of unpolarized charged leptons on polarized protons, $\ell^{\mp} + \vec P\to \stackrel{\scriptscriptstyle(-)}{ν_{\ell}} + X$, could provide a sensitive test for the behavior and magnitude of the polarized strange--quark density in a proton. Below charm threshold these processes are also helpf

S. Heinemeyer, W. Hollik

In the minimal supersymmetric standard model the decay $h^0 \to A^0A^0$ of the light neutral scalar $h^0$ is kinematically allowed for low values of $\tanβ$ when radiative corrections to the neutral Higgs masses are taken into account. The width of this decay mode is revisited on the basis of a complete 1-loop diagrammatic calculation. We give the analytical

Jae Kwan Kim, Pyungwon Ko, Kang Young Lee, Serge Rudaz

We consider the $a_{1} (1260)$ contribution to photon and dilepton productions from hot hadronic matter. The effective lagrangian with $π, ρ$ and $a_{1}$ discussed by Ko and Rudaz is employed, which successfully reproduces the $Γ(a_{1} \rightarrow πγ) = 670$ keV. Our results for the photon production rate are comparable to those obtained by Xiong {\it et al.

S. Fischer, A. Frommer, U. Glaessner, Th. Lippert

We present a parallelizable SSOR preconditioning scheme for Krylov subspace iterative solvers which proves to be efficient in lattice QCD applications involving Wilson fermions. Our preconditioner is based on a locally lexicographic ordering of the lattice points. In actual hybrid Monte Carlo applications with the bi-conjugate gradient stabilized method BiCG

Artan Borici

We estimate theoretically the cost of the multi-boson method in the non-hermitian approximation. It is shown that it is proportional to $V(\log V)^2/m^4$. For a global update of the scalar fields the cost decreases by a factor $m$ with a $\log V$ overhead.

Halina Abramowicz, David Horn, Ury Naftaly, Carmit Sahar-Pikielny

We propose a novel method for identification of a linear pattern of pixels on a two-dimensional grid. Following principles employed by the visual cortex, we employ orientation selective neurons in a neural network which performs this task. The method is then applied to a sample of data collected with the ZEUS detector at HERA in order to identify cosmic muon

T. Brotz, C. Kiefer

We elaborate on a proposal made by Greensite and others to solve the problem of time in quantum gravity. The proposal states that a viable concept of time and a sensible inner product can be found from the demand for the Ehrenfest equations to hold in quantum gravity. We derive and discuss in detail exact consistency conditions from both Ehrenfest equations

Omri Gat, Zeev Olami

We discuss the behavior of bounded slope quenched noise invasion models in high dimensions. We first observe that the roughness of such a steady state interface is generated by the combination of the roughness of the invasion process $χ_c$ and the roughness of the underlying interface dynamics. In high enough dimension we argue that $χ_c$ decreases to zero.

M. P. Nightingale, H. W. J. Bloete

The principle and the efficiency of the Monte Carlo transfer-matrix algorithm are discussed. Enhancements of this algorithm are illustrated by applications to several phase transitions in lattice spin models. We demonstrate how the statistical noise can be reduced considerably by a similarity transformation of the transfer matrix using a variational estimate

D. A. Head, G. J. Rodgers

We study the effects of generalised surface disorder on the monomer-monomer model of heterogeneous catalysis, where disorder is implemented by allowing different adsorption rates for each lattice site. By mapping the system in the reaction-controlled limit onto a kinetic Ising model, we derive the rate equations for the one and two-spin correlation functions

Johannes Voit

We calculate the spectral function of the Luther-Emery model which describes one-dimensional fermions with gapless charge and gapped spin degrees of freedom. We find a true singularity with interaction dependent exponents on the gapped spin dispersion and a finite maximum depending on the magnitude of the spin gap, on a shifted charge dispersion. We apply th

Y. Wang, J. Voit, F. -C. Pu

Using the principles of the conformal quantum field theory and the finite size corrections of the energy of the ground and various excited states, we calculate the boundary critical exponents of single- and multicomponent Bethe ansatz soluble models. The boundary critical exponents are given in terms of the dressed charge matrix which has the same form as th

Peter J. Forrester, Josef A. Zuk

The characteristic multi-dimensional integrals that represent physical quantities in random-matrix models, when calculated within the supersymmetry method, can be related to a class of integrals introduced in the context of two-dimensional conformal field theories by Dotsenko & Fateev. Known results on these Dotsenko-Fateev integrals provide a means by which

Anne-Marie Daré, Y. M. Vilk, A. -M. S. Tremblay

The crossover from two- to three-dimensional critical behavior of nearly antiferromagnetic itinerant electrons is studied in a regime where the inter-plane single-particle motion of electrons is quantum-mechanically incoherent because of thermal fluctuations. This is a relevant regime for very anisotropic materials like the cuprates. The problem is studied w

Bruce M. Boghosian, Jeffrey Yepez, Francis J. Alexander, Norman H. Margolus

We generalize the hydrodynamic lattice gas model to include arbitrary numbers of particles moving in each lattice direction. For this generalization we derive the equilibrium distribution function and the hydrodynamic equations, including the equation of state and the prefactor of the inertial term that arises from the breaking of galilean invariance in thes

Erkan TIN, Varol AKMAN

Serious thinking about the computational aspects of situation theory is just starting. There have been some recent proposals in this direction (viz. PROSIT and ASTL), with varying degrees of divergence from the ontology of the theory. We believe that a programming environment incorporating bona fide situation-theoretic constructs is needed and describe our v

Karl B. Fisher, John N. Bahcall, Sofia Kirhakos, Donald P. Schneider

We examine the clustering of galaxies around a sample of 20 luminous low redshift (z<0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope. The HST resolution makes possible galaxy identification brighter than V=23.5 and as close as 2&#39;&#39; to the quasar. We find a significant enhancement of galaxies within a projected separat

John Ellis

At the request of the organizers, this talk surveys some of the hot topics discussed at this meeting, giving my {\it subjective views} on them. Subjects covered include the present age and Hubble expansion rate of the Universe - {\it inflation theorists need not yet abandon $Ω= 1$}, theories of structure formation in the light of COBE and other data - {\it m

Tetsu Kitayama, Yasushi Suto

Analytical expressions for the rates of formation and destruction of gravitationally bound systems are derived assuming that they are originated from primordial random-Gaussian density fluctuations. The resulting formulae reproduce the time derivative of the Press-Schechter mass function in a certain limit. Combining a theoretical model for the evolution of

Yasushi Suto

Since recent X-ray observations have revealed that most clusters of galaxies are surrounded by an X-ray emitting gaseous halo, it is reasonable to expect that the Local Group of galaxies has its own X-ray halo. We show that such a halo, with temperature $\sim 1\keV$ and column density $\sim O(10^{21}) {\rm cm}^{-2}$, is a possible source for the excess low-e

I. Cassidy, D. J. Raine

We compute the line strengths and profiles from a model of the cloud dynamics of the broad and intermediate line regions and compare the results with the observations of the Seyfert galaxy NGC 4151 in its various luminosity states.

G. Tagliaferri, G. Bao, G. L. Israel, L. Stella

We present a detailed cross-correlation (CCF) and power spectrum re-analysis of the X-ray light curves of the bright Seyfert 1 galaxy NGC5548 obtained with EXOSAT. The 0.05-2 keV and 1-4 keV light curves are cross--correlated with the 1-9 keV and 4-9 keV light curves respectively. We discuss how spurious time lags can be introduced by systematic effects rela

F. Bernardeau

It is known that in gravitational instability scenarios the nonlinear dynamics induces non-Gaussian features in cosmological density fields that can be investigated with perturbation theory. Here, I derive the expression of the joint moments of cosmological density fields taken at two different locations. The results are valid when the density fields are fil

Michael B. Christiansen, Jes Madsen

We calculate the mean nucleation distance, $d_{nuc}$, in a first order cosmological quark-hadron phase transition. For homogeneous nucleation we find that self-consistent inclusion of curvature energy reduces $d_{nuc}$ to $\lesssim 2$cm. However, impurities can lead to heterogeneous nucleation with $d_{nuc}$ of several meters, a value high enough to change t

Tanaji Sen, James A. Ellison

Random fluctuations in the tune, beam offsets and beam size in the presence of the beam-beam interaction are shown to lead to significant particle diffusion and emittance growth in hadron colliders. We find that far from resonances high frequency noise causes the most diffusion while near resonances low frequency noise is responsible for the large emittance

David H. Adams

A geometric formal method for perturbatively expanding functional integrals arising in quantum gauge theories is described when the spacetime is a compact riemannian manifold without boundary. This involves a refined version of the Faddeev-Popov procedure using the covariant background field gauge-fixing condition with background gauge field chosen to be a g

Pilar Hernandez, Raman Sundrum

We propose a method for interpolating non-abelian lattice gauge fields to the continuum, or to a finer lattice, which satisfies the properties of (i) transverse continuity, (ii) (lattice) rotation and translation covariance, (iii) gauge covariance, (iv) locality. These are the properties required for use in our earlier proposal for non-perturbative formulati

A. G. Ushveridze

The relationship between the quasi-exactly solvable problems and W-algebras is revealed. This relationship enabled one to formulate a new general method for building multi-dimensional and multi-channel exactly and quasi-exactly solvable models with hermitian hamiltonians. The method is based on the use of multi-parameter spectral differential equations const

Amnon Yekutieli

Beilinson Completion Algebras (BCAs) are generalizations of complete local rings, and have a rich algebraic-analytic structure. These algebras were introduced in my paper &#34;Traces and Differential Operators over Beilinson Completion Algebras&#34;, Compositio Math. 99 (1995). In the present paper BCAs are used to give an explicit construction of the Grothe

C. Y. Cheung, C. W. Hwang, W. M. Zhang

A consistent treatment of $B\rightarrow πl ν$ decay is given on the light-front. The $B$ to $π$ transition form factors are calculated in the entire physical range of momentum transfer for the first time. The valence-quark contribution is obtained using relativistic light-front wave functions. Higher quark-antiquark Fock-state of the $B$-meson bound state is

S. Lukyanov, Ya. Pugai

By using the bosonization technique, we derive an integral representation for multi-point Local Hight Probabilities for the Andrews-Baxter-Forrester model in the regime III. We argue that the dynamical symmetry of the model is provided by the deformed Virasoro algebra.

Kikuo Harigaya

Exciton effects on conjugated polymers and the resulting optical nonlinearities are investigated in soliton lattice states. We use the Su-Schrieffer-Heeger model with long-range Coulomb interactions for electrons. The third-harmonic generation (THG) at off-resonant frequencies is calculated as functions of the soliton concentration and the chain length of th

A. Borrelli, Ph. de Forcrand, A. Galli

We present an exact version of the local bosonic algorithm for the simulation of dynamical quarks in lattice QCD. This version is based on a non-hermitian polynomial approximation of the inverse of the quark matrix. A Metropolis test corrects the systematic errors. Two variants of this test are presented. For both of them, a formal proof is given that this M

Katsushi Ito, Naoki Sasakura

We calculate the one-instanton contribution to the prepotential in $N=2$ supersymmetric $SU(N_c)$ Yang-Mills theory from the microscopic viewpoint. We find that the holomorphy argument simplifies the group integrations of the instanton configurations. For $N_{c}=3$, the result agrees with the exact solution.

Yoshio Koide, Hideo Fusaoka

We investigate a seesaw type mass matrix $M_f\simeq m_L M_F^{-1} m_R$ for quarks and leptons, $f$, under the assumptions that the matrices $m_L$ and $m_R$ have common structures for the quarks and leptons, and that the matrix $M_F$ characterizing the heavy fermion sector has the form [(unit matrix)+ (democratic-type matrix)]. We obtain well-satisfied relatio

Robin G. Stuart

General model-independent expressions are developed for the polarized and unpolarized cross-sections for $e^+e^-\to f\bar f$ near the $Z^0$ resonance. The expressions assume only the analyticity of S-matrix elements. Angular dependence is included by means of a partial wave expansion. The resulting simple forms are suitable for use in fitting data or in Mont

L. Frankfurt, V. Guzey, M. Strikman

The Bjorken sum rules for the $A=3$ and $A=1$ are used as a guide to estimate nuclear effects in extracting $g_{1n}(x,Q^{2})$ from the $\vec{e}\,\vec{^3\rm{He}}$ data. We estimate that the combination of the spin depolarization, the nonnucleonic degrees of freedom in the $A=3$ system and nuclear shadowing is likely to reduce $g_{1^3\rm{He}}(x\le 0.05)$ by $\

C. Reichhardt, C. J. Olson, J. Groth, Stuart Field

We present simulations of flux-gradient-driven superconducting vortices interacting with strong columnar pinning defects as an external field $H(t)$ is quasi-statically swept from zero through a matching field $B_ϕ$. We analyze several measurable quantities, including the local flux density $ B(x,y,H(t))$, magnetization $M(H(t))$, critical current $J_{c}(B(t

A. Scotti, A. Ushveridze

It is demonstrated that the so-called &#34;unavoidable quantum anomalies&#34; can be avoided in the farmework of a special non-linear quantization scheme. A simple example is discussed in detail.

Dmitry Fuchs, Lynelle Lang

The classical deformation theory of Lie algebras involves different kinds of Massey products of cohomology classes. Even the condition of extendibility of an infinitesimal deformation to a formal one-parameter deformation of a Lie algebra involves Massey powers of two dimensional cohomology classes which are not powers in the usual definition of Massey produ

Brendan B. Plapp, Eberhard Bodenschatz

We report experimental observations of the core dynamics of multi-armed, rotating spirals in Rayleigh-Benard convection for a fluid with Prandtl number near one. In addition to the large-scale rotation of the spirals, we found a cyclic core motion within a central area of radius r = appr. (n lambda/2), where n is the number of spiral arms ending in the core

C. Ciofi degli Atti, S. Scopetta, A. Yu. Umnikov, L. P. Kaptari

The nuclear effects in the spin-dependent structure function $g_1$ of the deuteron are studied in the kinematics of future experiments at CEBAF, ($ν\leq 3~GeV, ~Q^2 \leq 2~GeV^2$). The magnitude of the nuclear effects is found to be significantly larger than the one occurring in deep inelastic scattering ($ν\to \infty, ~Q^2\to \infty$). We discuss the mechan

Bengt Friman, Mannque Rho

A simple relation between the effective parameters of chiral Lagrangians in medium as predicted by BR scaling and Landau Fermi liquid parameters is derived. This provides a link between an effective theory of QCD at mean-field level and many-body theory of nuclear matter. It connects in particular the scaling vector-meson mass probed by dileptons produced in

S. S. Kamalov, L. Tiator, C. Bennhold

Pion elastic scattering on deuterium is studied in the KMT multiple scattering approach developed in momentum space. Using a Paris wave function and the same methods and approximations as commonly used in pion scattering on heavier nuclei excellent agreement with differential cross section data is obtained for a wide range of pion energies. Only for $T_π>250

S. S. Kamalov, L. Tiator, C. Bennhold

Coherent pion photoproduction, $d(γ,π^0)d$, is calculated in a coupled channels approach in momentum space using an elementary production operator that includes Born terms, vector meson exchange and $M1/E2$ $Δ$-resonance excitation. The final state interaction is treated in the KMT multiple scattering approach that describes $πd$ elastic scattering well. Dif

P. A. M. Guichon, K. Saito, A. W. Thomas

We describe the development of a theoretical description of the structure of finite nuclei based on a relativistic quark model of the structure of the bound nucleons which interact through the (self-consistent) exchange of scalar and vector mesons.

E. J. Beise, D. H. Beck, E. Candell, R. Carr

Parity-violating electron scattering measurements on hydrogen and deuterium, such as those underway at the Bates and CEBAF laboratories, require luminosities exceeding $10^{38}$cm$^{-2}$s$^{-1}$, resulting in large beam power deposition into cryogenic liquid. Such targets must be able to absorb 500 watts or more with minimal change in target density. A 40~cm

S. James Gates,, Lubna Rana

We show via use of the RADIO technique that an off-shell (4,0) version of the hypermultiplet, in the form first proposed by Fayet, exists and contains 28 - 28 component fields. The off-shell structure uncovered is found to include a chiral truncation of the ``generalized 2D, N = 4 tensor multiplet formalism&#39;&#39; proposed by Ketov. The (4,0) theory is ex

Katrin Becker, Melanie Becker

We formulate boundary conditions for an open membrane that ends on the fivebrane of {\cal M}-theory. We show that the dynamics of the eleven-dimensional fivebrane can be obtained from the quantization of a ``small membrane&#39;&#39; that is confined to a single fivebrane and which moves with the speed of light. This shows that the eleven-dimensional fivebran

M. Kacir, M. Prakash, I. Zahed

In a dilute system of instantons and antiinstantons, the U$_{\rm A}$(1) and scale anomalies are shown to be directly related to the bulk susceptibility and compressibility of the system. Using $1/N_c$ (where $N_c$ is the number of colors) as a book-keeping argument, mesonic, baryonic and gluonic correlators are worked out in p-space and Fourier transformed t

Alexander Moroz, Jan Fischer

A generic physical situation is considered where Im $Π$, the imaginary part of polarization operator (generalized susceptibility), can be measured on a finite interval and the high frequency asymptotics (up to a few orders) of $Π$ can be calculated theoretically. In such a case, it is desirable to derive an equivalent form of the Kramers-Kronig dispersion re

Richard E. Stuckey, Michael C. Birse

The chiral expansion of the one-loop corrections to baryon masses is examined in a generic meson-cloud model with meson-baryon form factors. For pion loops, the expansion is rapidly convergent and at fourth order in $m_π$ accurately reproduces the full integral. In contrast, the expansion is found to converge very slowly for kaon loops, raising questions abo

Roman Jackiw

These days, as high energy particle colliders become unavailable for testing speculative theoretical ideas, physicists are looking to other environments that may provide extreme conditions where theory confronts physical reality. One such circumstance may arise at high temperature $T$, which perhaps can be attained in heavy ion collisions or in astrophysical

Boris Blok, Cai-Dian Lu, Da-Xin Zhang

We study the influence of messenger Yukawa couplings and top, bottom and $τ$ Yukawa couplings on the proton lifetime in SU(5) Supersymmetric GUT with dynamical supersymmetry breaking mechanism due to Dine and Nelson.

O. K. Kalashnikov

Using the Slavnov-Taylor identities we prove that the so-called &#34;magnetic mass&#34; is exactly equal to zero within hot scalar electrodynamics. The same result is valid for hot QED and seems for any abelian theory but this is not the case for hot QCD where one expects that $\m\ne 0$.

H. Nunokawa, A. Rossi, V. B. Semikoz, J. W. F. Valle

We consider the implications of solar matter density random noise upon resonant neutrino conversion. The evolution equation describing MSW-like conversion is derived in the framework of the Schrödinger approach. We study quantitatively their effect upon both large and small mixing angle MSW solutions to the solar neutrino problem. This is carried out both fo

M. Hirsch, H. V. Klapdor-Kleingrothaus, O. Panella

Left-right symmetric models provide a natural framework for neutrinoless double beta ($\znbb$) decay. In the analysis of $\znbb$ decay in left-right symmetric models, however, it is usually assumed that all neutrinos are light. On the other hand, heavy {\it right-handed} neutrinos appear quite naturally in left-right symmetric models and should therefore not

M. Hirsch, H. V. Klapdor-Kleingrothaus, S. G. Kovalenko

We discuss an extension of the standard model (SM) with vector and scalar leptoquarks. The renormalizable leptoquark Lagrangian consistent with the SM gauge symmetry is presented including the leptoquark-Higgs interactions previously not considered in the literature. We discuss the importance of these new interactions for leptoquark phenomenology. After the

Bernd A. Kniehl

By means of a low-energy theorem, we analyze at O(alpha_s G_F M_Q^2) the shifts in the Standard-Model W^+W^-H and ZZH couplings induced by virtual high-mass quarks, Q, with M_Q >> M_Z, M_H, which includes the top quark. Invoking the improved Born approximation, we then find the corresponding corrections to various four- and five-point Higgs-boson production

Giampiero Passarino

The program WTO, which is designed for computing cross sections and other relevant observables in the $e^+e^-$ annihilation into four fermions, is described. The various quantities are computed over both a completely inclusive experimental set-up and a realistic one, i.e. with cuts on the final state energies, final state angles, scattering angles and final

Toby Falk, Keith A. Olive

We consider constraints on $\cp$-violating phases in the Constrained Minimal Supersymmetric Standard Model. We find that by combining cosmological limits on gaugino masses with experimental bounds on the neutron and electron electric dipole moments, we can constrain the phase of the Higgs mixing mass $μ$ to be $|θ_μ| < π/10$, independent of choices of the ot

Claudio Coriano, L. E. Gordon

We present a complete order $α_s$ analysis of the process $p p\to γγ+ X$ with polarized initial states, previously studied by us with leading order structure functions. We include in our calculation new sets of parton densities evolved in NLO QCD, such as those of Gehrmann and Stirling and of Glück et al., which incorporate the new anomalous dimensions of Me

I. Joseph Kroll

The latest measurements of the masses and lifetimes of weakly decaying $B$~hadrons from experiments at $e^+e^-$ and $p\bar{p}$ colliders are presented. These measurements include the lifetimes of the $\bar{B}^0$, $\bar{B}^0_s$, $B^-$, and $b$~baryons, as well as searches for the $B_c$~meson. The observation of $B^*$, p-wave B~mesons ($B^{**}$), and excited $

L. A. Hamel, L. Lessard, V. Zacek, Bhaskar Sur

We suggest the use of moderately superheated liquids in the form of superheated droplet detectors for a new type of neutralino search experiment. The advantage of this method for Dark Matter detection is, that the detector material is cheap, readily available and that it is easily possible to fabricate a large mass detector. Moreover the detector can be made

Hans-Peter Nollert

Quasinormal modes have played a prominent role in the discussion of perturbations of black holes, and the question arises whether they are as significant as normal modes are for self adjoint systems, such as harmonic oscillators. They can be significant in two ways: Individual modes may dominate the time evolution of some perturbation, and a whole set of the

M. Toller

A class of free quantum fields defined on the Poincare&#39; group, is described by means of their two-point vacuum expectation values. They are not equivalent to fields defined on the Minkowski spacetime and they are &#34;elementary&#34; in the sense that they describe particles that transform according to irreducible unitary representations of the symmetry

Yasunori Fujii

Based on a thoeretical model in which scalar fields play crucial roles, we propose a mechanism to better understand a cosmological constant expected to be small (nearly comparable with the critical density) but nonzero as suggested strongly by the recent observations. We emphasize that a step further is needed beyond the simplest scenario of a decaying cosmo

Alexander Reznikov

This is a first in a series of papers, devoted to the relation betwwen three-manifolds and number fields. The present paper studies first homology of finite coverings of a three-manifold with primary interest in the Thurston $b_1$ conjecture.The main result reads: if $M$ does not yield the Thurston conjecture, then the pro-p completion of its fundamental gro

Wolfgang Häusler

The lowest eigenenergies of few, strongly interacting electrons in a one--dimensional ring are studied in the presence of an impurity barrier. The persistent current $\:I\:$, periodic in an Aharonov--Bohm flux penetrating the ring, is strongly influenced by the electron spin. The impurity does not remove discontinuities in $\:I\:$ at zero temperature. The to

J. M. Normand, H. J. Herrmann

Using 20 months of CPU time on our special purpose computer ``Percola&#39;&#39; we determined the exponent for the normal conductivity at the threshold of three-dimensional site and bond percolation. The extrapolation analysis taking into account the first correction to scaling gives a value of $t/ν= 2.26\pm 0.04$ and a correction exponent $ω$ around 1.4.

H. Niggemann, J. Zittartz

We present a set of {\em optimum ground states} for a large class of spin-$\frac{3}{2}$ chains. Such global ground states are simultaneously ground states of the local Hamiltonian, i.e. the nearest neighbour interaction in the present case. They are constructed in the form of a matrix product. We find three types of phases, namely a {\em weak antiferromagnet

Y K Zhou, M T Batchelor

We consider the $L$-state cyclic solid-on-solid lattice models under a class of open boundary conditions. The integrable boundary face weights are obtained by solving the reflection equations. Functional relations for the fused transfer matrices are presented for both periodic and open boundary conditions. The eigen-spectra of the unfused transfer matrix is

Andrey V. Chubukov, Oleg A. Starykh

We consider an anisotropic version of the $CP^{1}$ model which describes frustrated quantum antiferromagnets with incommensurate spin correlations. We extend the two-component spinon field, describing lattice spins, to the $M$-component complex vector, and show, in the $1/M$ expansion, that for arbitrary small incommensurability longitudinal and transverse s

Daniel Hoffmann, Ernst-Walter Knapp

A Monte Carlo method for dynamics simulation of all-atom protein models is introduced, to reach long times not accessible to conventional molecular dynamics. The considered degrees of freedom are the dihedrals at C$_α$-atoms. Two Monte Carlo moves are used: single rotations about torsion axes, and cooperative rotations in windows of amide planes, changing th

Franz Josef Weiper, Joachim Ankerhold, Hermann Grabert

We present a barrier potential with bound states that is exactly solvable and determine the eigenfunctions and eigenvalues of the Hamiltonian. The equilibrium density matrix of a particle moving at temperature T in this nonlinear barrier potential field is determined. The exact density matrix is compared with the result of the path integral approach in the s

Roman Scoccimarro, Josh Frieman

We calculate the lowest-order non-linear contributions to the power spectrum, two-point correlation function, and smoothed variance of the density field, for Gaussian initial conditions and scale-free initial power spectra, $P(k) \sim k^n$. These results extend and in some cases correct previous work in the literature on cosmological perturbation theory. Com