January 1995 arXiv papers — page 7

P. Kosi{ń}ski, J. Lukierski, P. Ma{ś}lanka, J. Sobczyk

The general framework of bicrossproduct Hopf algebras given by Majid is extended to $Z_2$-graded bicrossproduct Hopf superalgebras. As examples of bicrossproduct Hopf superalgebras we provide the graded algebras of functions on undeformed as well as $κ$-deformed $D=4$ Poincaré supergroups.

B. G. Giraud, Y. Hahn

An elementary proof of the 3-body Efimov effect is provided in the case of a separable 2-body potential which binds at zero energy a light particle to a heavy one. The proof proceeds by two steps, namely {\it i)} a projection of the Hamiltonian in a subspace and the observation that the projected Hamiltonian generates an arbitrarily large number of bound sta

D. Bernard. V. Pasquier, D. Serban

We consider integrable models of the Haldane-Shastry type with open boundary conditions. We define monodromy matrices, obeying the reflection equation, which generate the symmetries of these models. Using a map to the Calogero-Sutherland Hamiltonian of BC type, we derive the spectrum and the highest weight eigenstates.

Kimyeong Lee, Piljin Yi

We study relativistic self-dual Chern-Simons-Higgs systems in the presence of uniform background fields that explicitly break CTP. A rich, but discrete vacuum structure is found when the gauge symmetry is spontaneously broken, while the symmetric phase can have an infinite vacuum degeneracy at tree level. The latter is due to the proliferation of neutral sol

D. Litim, N. Tetradis

We study exact renormalization group equations in the framework of the effective average action. We present analytical approximate solutions for the scale dependence of the potential in a variety of models. These solutions display a rich spectrum of physical behaviour such as fixed points governing the universal behaviour near second order phase transitions,

Manuel Torres

We show the existence of self-dual semilocal nontopological vortices in a $Φ^2$ Chern-Simons (C-S) theory. The model of scalar and gauge fields with a $SU(2)_{global} \times U(1)_{local}$ symmetry includes both the C-S term and an anomalous magnetic contribution. It is demonstrated here, that the vortices are stable or unstable according to whether the vecto

Esteban Calzetta, B. L. Hu

The statistical mechanical properties of interacting quantum fields in terms of the dynamics of the correlation functions are investigated. We show how the Dyson - Schwinger equations may be derived from a formal action functional, the n-particle irreducible ($nPI, n \to \infty$) or the `master' effective action. It is related to the decoherence function

Lori Paniak, Nathan Weiss

The Kazakov--Migdal (KM) Model is a U(N) Lattice Gauge Theory with a Scalar Field in the adjoint representation but with no kinetic term for the Gauge Field. This model is formally soluble in the limit $N\rightarrow \infty$ though explicit solutions are available for a very limited number of scalar potentials. A ``Double Penner'' Model in which the p

Manuel Drees

After briefly reviewing past accomplishments of TRISTAN experiments in the field of inclusive two--photon reactions, I discuss open problems in the Monte Carlo simulation of such reactions. The main emphasis is on multiple scattering, i.e. events where at least two pairs of partons scatter within the same \gaga collision to form at least four (mini)jets. The

Jiri Chyla

The accuracy of the conventional treatment of quark mass thresholds in the QCD running coupling constant $α_s$, based on the step approximation to the $β$--function, is investigated. The errors of extrapolating $\ase(μ)$ from low energies to $μ=M_Z$, implied by this approximation, are shown to be of the same magnitude as the typical next--to--next--to--leadi

Isard Dunietz

A width difference of the order of 20\% has previously been predicted for the two mass eigenstates of the $B_s$ meson. The dominant contributor to the width difference is the $b\rightarrow c\bar c s$ transition, with final states common to both $B_s$ and $\overline{B}_s$. All current experimental analyses fit the time-dependences of flavor-specific $B_s$-mod

Stefan Dittmaier, Carsten Grosse-Knetter

We describe a method to remove non-decoupling heavy fields from a quantized field theory and to construct a low-energy one-loop effective Lagrangian by integrating out the heavy degrees of freedom in the path integral. We apply this method to the Higgs boson in a spontaneously broken SU(2) gauge theory (gauged linear sigma-model). In this context, the backgr

Alejandra Melfo, Leandros Perivolaropoulos

Using a toy model Lagrangian we investigate the formation of vortices in first order phase transitions. The evolution and interactions of vacuum bubbles are also studied using both analytical approximations and a numerical simulation of scalar field dynamics. A long lived bubble wall bound state is discovered and its existence is justified by using a simplif

H. Athar, J. T. Peltoniemi, A. Yu. Smirnov

We study the spin-flavor transitions of neutrinos in the magnetic fields of a collapsing star. For the neutrino mass squared difference (10^{-10} - 10) eV^2 the transitions take place in almost isotopically neutral region of the star, where the effective matter density is suppressed up to 3 - 4 orders of magnitude. This suppression is shown to increase the s

W. Melnitchouk, G. Piller, A. W. Thomas

The spin-dependent structure function of the deuteron, g_1D, is calculated within a covariant framework. The off-shell structure of the bound nucleon gives corrections to the convolution model at a level of half a percent for x below 0.7, increasing to more than five percent at larger x. Overall, the dominant source of error comes from the lack of knowledge

A. J. Buras, M. Muenz

We calculate the next-to-leading QCD corrections to the effective Hamiltonian for \Bsee in the NDR and HV schemes. We give for the first time analytic expressions for the Wilson Coefficient of the operator $Q_9 = (\bar s b)_{V-A}(\bar e e)_V$ in the NDR and HV schemes. Calculating the relevant matrix elements of local operators in the spectator model we demo

K. --I. Kondo, P. Maris

In three-dimensional QED with a Chern--Simons term we study the phase structure associated with chiral-symmetry breaking in the framework of the Schwinger--Dyson equation. We give detailed analyses on the analytical and numerical solutions for the Schwinger--Dyson equation of the fermion propagator, where the nonlocal gauge-fixing procedure is adopted to avo

D. Espriu, J. Matias

We perform an exhaustive analysis of the Equivalence Theorem both in the minimal Standard Model and in an Effective Electroweak Chiral Lagrangian up to ${\cal O}(p^4)$. We have considered the leading corrections to the usual prescription consisting in just replacing longitudinally polarized $W$ or $Z$ by the corresponding Goldstone bosons. The corrections ap

Wolfgang LUCHA, Franz F. SCHÖBERL

We construct effective Hamiltonians which despite their apparently nonrelativistic form incorporate relativistic effects by involving parameters which depend on the relevant momentum. For some potentials the corresponding energy eigenvalues may be determined analytically. Applied to two-particle bound states, it turns out that in this way a nonrelativistic t

Jonathan Bagger, Konstantin Matchev, Damien Pierce

We compute the full set of weak-scale gauge and Yukawa threshold corrections in the minimal supersymmetric standard model, including all finite (non-logarithmic) corrections, which we show to be important. We use our results to examine the effects of unification-scale threshold corrections in the minimal and missing-doublet SU(5) models. We work in the conte

Dongsheng Liu

Forward-backward charge asymmetry in rare dilepton $B$-decays is formulated with the assumption of an on-shell b-quark. We find the asymmetry is expressed in terms of two spatially transverse helicity amplitudes, which are determined by combining the data of $D\rightarrow K^*(892)\; l^+ ν$ with heavy flavour symmetry. We estimate the charge asymmetry of $B\r

Jeffrey Grandy, Rajan Gupta

We present an update on the study of topological structure of QCD. Issues addressed include a comparison between the plaquette and the geometric methods of calculating the topological density. We show that the improved gauge action based on sqrt(3) blocking transformation suppresses the formation of topologically charged dislocations with low action. Using a

R. Kenna, A. C. Irving

By expressing thermodynamic functions in terms of the edge and density of Lee--Yang zeroes, we relate the scaling behaviour of the specific heat to that of the zero field magnetic susceptibility in the thermodynamic limit of the $XY$--model in two dimensions. Assuming that finite--size scaling holds, we show that the conventional Kosterlitz--Thouless scaling

J. -F. Lagae, K. -F. Liu

We compute the $ma$ dependence of lattice renormalization factors for sea quark matrix elements. The results differ from the $(1+ma)$ correction factor commonly used for valence quarks and connected current insertions. We find that for sea quarks, the correction factors are in general larger and depend strongly on the Lorentz structure of the current under c

David Scialom, Philippe Jetzer

We study the coupled Einstein-Klein-Gordon equations for a complex scalar field with and without a quartic self-interaction in a curvatureless Friedman-Lema\^ı\-tre Universe. The equations can be written as a set of four coupled first order non-linear differential equations, for which we establish the phase portrait for the time evolution of the scalar field

Sören Holst

In 1991 Gott presented a solution of Einstein&#39;s field equations in 2+1 dimensions with $Λ= 0$ that contained closed timelike curves (CTC&#39;s). This solution was remarkable because at first it did not seem to be unphysical in any other respect. Later, however, it was shown that Gott&#39;s solution is tachyonic in a certain sense. Here the case $Λ< 0$ is

Constantino Tsallis, Daniel A. Stariolo

We propose a new stochastic algorithm (generalized simulated annealing) for computationally finding the global minimum of a given (not necessarily convex) energy/cost function defined in a continuous D-dimensional space. This algorithm recovers, as particular cases, the so called classical (&#34;Boltzmann machine&#34;) and fast (&#34;Cauchy machine&#34;) sim

Giorgio Parisi

In this paper, after a telegraphic introduction to modern immunology, we present a simple model for the idiotypic network among antibodies and we study its relevance for the maintenance of immunological memory. We also consider the problem of computing the memory capacity of such a model.

Giorgio Parisi

In this note we study the zero temperature dynamics of the Sherrington Kirkppatric model and we investigate the statistical properties of the configurations that are obtained in the large time limit. We find that the replica symmetry is broken (in a weak sense). We also present some general considerations on the synchronic approach to the off-equilibrium dyn

E. G. D. Cohen, F. Wang

New calculations to over ten million time steps have revealed a more complex diffusive behavior than previously reported, of a point particle on a square and triangular lattice randomly occupied by mirror or rotator scatterers. For the square lattice fully occupied by mirrors where extended closed particle orbits occur, anomalous diffusion was still found. H

Robert Brandenberger, Anne-Christine Davis, Martin J. Rees

In the defect-mediated electroweak baryogenesis scenario, baryons are produced in well separated regions of space. It is shown that between the electroweak phase transition at a temperature of $T \sim 100 {\rm GeV}$ and the end of nucleosynthesis at $T \sim 1 {\rm KeV}$ the baryon inhomogeneities dissipate, and that no constraints on defect-mediated electrow

Fred Adams, Richard Watkins

We discuss the physics of vortices in the circumstellar disks associated with young stellar objects. We elucidate the basic physical properties of these localized storm systems. In particular, we consider point vortices, linear vortices, the effects of self-gravity, magnetic fields, and nonlinear aspects of the problem. We find that these vortices can exist

Gianluigi Bodo, Gabriele Ghisellini

We calculate the flux and size ratio of radio emitting features moving in antiparallel directions at relativistic speeds, taking into account that the pattern we observe may move at a velocity different from the one of the emitting plasma. Both velocities can be determined in sources in which both the approaching and the receding features are observed. This

P. G. Grinevich, S. P. Novikov

This paper is a continuation of the paper by S.P.Novikov in Funct.Anal.Appl., v.24(1990), No 4, pp 196-206. String equation is by definition the equation $[L,A]=1$ for the coefficients of two linear ordinary differential operators $L$ and $A$. For the ``double scaling limit&#39;&#39; of the matrix model we always have $L=-\partial_x^2+u(x)$, $A$ is some diff

Rachel Jeannerot, Anne-Christine Davis

We study the impact of the symmetry breaking patterns from supersymmetric SO(10) down to the standard model on the standard big-bang cosmology through the formation of topological defects. None of the models is consistent with the standard cosmology without invoking any mechanism to solve the monopole problem. For this purpose, we use a hybrid false vacuum i

L. L. Salcedo, K. Holinde, E. Oset, C. Schütz

We evaluate the contribution of second order terms to the pion-nucleus s-wave optical potential of pionic atoms generated by short range nuclear correlation. The corrections are sizeable because they involve the isoscalar s-wave $πN$ amplitude for half off-shell situations where the amplitude is considerably larger than the on-shell one. In addition, the s-w

G. Cvetic, E. A. Paschos, N. D. Vlachos

We study dynamical symmetry breaking in the Standard Model including the next-to-leading order terms. We introduce at a high, but finite, energy scale Lambda a top quark condensate H={t {bar t}} and derive, using path integral methods, the effective potential including quadratic fluctuations in the scalar field H. We neglect the contributions of all componen

Jens Jensen

The equations of motion of dipolar-coupled spins of I=1/2 placed on a rigid lattice are solved approximately in the high-temperature and high-field limit. The NMR-spectra predicted by this theory are in close agreement with both the theoretical spectral moments, up to the eighth in the case of a simple cubic lattice, and the extremely accurate experimental r

Mark B. Mineev-Weinstein

An infinite number of conserved quantities in the field dynamics $ϕ_t = L U(ϕ) + ρ$ for a linear Hermitian (or anti-Hermitian) operator $L$, an arbitrary function $U$ and a given source $ρ$ are presented. These integrals of motion are the multipole moments of the potential created by $ϕ$ in the far-field. In the singular limit of a bistable scalar field $ϕ=

Fabian H. L. Essler, Vladimir E. Korepin

We study zero temperature correlation functions of the spin-$1\over 2$ Heisenberg XXZ model in the critical regime $-1< Δ\leq 1$ in a magnetic field by means of the {\tenit Dual Field Approach}. We show for one particular example how to derive determinant representations for correlation functions and how to use these to embed the correlation functions in int

Hilmar Forkel, A. D. Jackson

The description of nuclear matter bulk properties in the framework of quark-based hadron models in curved unit cells is extended to finite temperature. We discuss the analogy and interplay of density and temperature effects in this formulation and study, as an application, the temperature and density dependence of chiral vacuum properties in the Nambu-Jona-L

H. Jünemann, A. Weiguny, B. G. Giraud

The time independent mean field method (TIMF) for the calculation of matrix elements of non relativistic propagators is based on a variational principle whose non linearity induces a multiplicity of variational solutions. Several of them can break any symmetry shared by the Hamiltonian and initial and final states. We describe a soluble model where, in parti

C. Gomez, E. Lopez

We derive the $t{\bar t}$-equations for generic $N\!=\!2$ topological field theories as consistency conditions for the contact term algebra of topological strings. A generalization of the holomorphic anomaly equation, known for the critical ${\hat c}\!=\!3$ case, to arbitrary non critical topological strings is presented. The interplay between the non trivia

David J. Fernández C., Luis M. Nieto, Oscar Rosas-Ortiz

The dynamical algebra associated to a family of isospectral oscillator Hamiltonians is studied through the analysis of its representation in the basis of energy eigenstates. It is shown that this representation becomes similar to that of the standard Heisenberg algebra, and it is dependent of a parameter $w\geq 0$. We name it {\it distorted Heisenberg algebr

F. Illuminati, L. Viola

We introduce a new variational characterization of Gaussian diffusion processes as minimum uncertainty states. We then define a variational method constrained by kinematics of diffusions and Schrödinger dynamics to seek states of local minimum uncertainty for general non-harmonic potentials.

Adel Bilal

In the present contribution, I report on certain {\it non-linear} and {\it non-local} extensions of the conformal (Virasoro) algebra. These so-called $V$-algebras are matrix generalizations of $W$-algebras. First, in the context of two-dimensional field theory, I discuss the non-abelian Toda model which possesses three conserved (chiral) ``currents&#34;. The

A. A. Babich, A. A. Pankov, N. Paver

We discuss the potential of a $0.5\hskip 2pt TeV$ linear collider to explore manifestations of extended (or alternative) electroweak models of current interest, through measurements of the reaction $e^+e^-\to W^+W^-$ with both initial and final states polarization. Specifically, we consider the possibility to put stringent constraints on lepton mixing (or ex

C. Adam

Using the exact path integral solution of the Schwinger model -- a model where instantons are present -- the Dyson-Schwinger equation is shown to hold by explicit computation. It turns out that the Dyson-Schwinger equation separately holds for every instanton sector. This is due to Theta-invariance of the Schwinger model.

G. Cynolter, E. Lendvai, G. Pocsik

Oblique radiative corrections are calculated to the parameter $S$ in a version of the standard model where the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. We show that to each momentum scale there exists a domain of the masses of charged and neutral vector bosons where $S$ is compatible with the exper

Sujan Sengupta, Palash B. Pal

Considering the observed anisotropy in cosmic microwave background radiation ($ΔT/T \leq 10^{-4}$) an upper limit on the electric charge asymmetry over a cosmological scale is found which is several orders more stringent than those found earlier. The same argument constrains the charge of massless, degenerate neutrinos.

Wolf-Dieter Nowak

The physics case is summarised for the investigation of high energy spin phenomena by placing an internal polarised target into HERA&#39;s unpolarised proton beam. The luminosity and experimental sensitivity are discussed. Estimating the physics reach of single spin asymmetries in different final states reveals a considerable physics potential in testing the

Harry J. Lipkin

Many theoretical calculations of subtle coherent effects in quantum mechanics do not carefully consider the interface between their calculations and experiment. Calculations for gedanken experiments using initial states not satisfied in realistic experiments give results requiring interpretation. Confusion and ambiguities frequently arise. Calculations for t

G. Montagna, O. Nicrosini, F. Piccinini

The production of the Standard Model Higgs boson in the four-fermion reaction $e^+ e^- \to μ^+ μ^- b \bar b$ is studied. The complete tree-level matrix element, including signal and backgrounds in the standard electroweak theory, is computed and initial state radiation is taken into account in the leading-log approximation. A Monte Carlo event generator has

T. W. B. Kibble, Alexander Vilenkin

In the context of an Abelian gauge symmetry, spontaneously broken at a first-order transition, we discuss the evolution of the phase difference between the Higgs fields in colliding bubbles. We show that the effect of dissipation, represented by a finite plasma conductivity, is to cause the phases to equlibrate on a time-scale, determined by the conductivity

M. Ciuchini, E. Franco, G. Martinelli, L. Reina

An upgraded analysis of $\ep$, $x_d$ and $\epp/\ep$, using the latest determinations of the relevant experimental and theoretical parameters, is presented. Using the recent determination of the top quark mass, $m_t=(174 \pm 17)$ GeV, our best estimate is $\epp/\ep= 3.1 \pm 2.5 $, which lies in the range given by E731. We describe our determination of $\epp/\

C. P. Bachas, T. N. Tomaras

We present some evidence, based on the analysis of lower-dimensional models, for the possible existence of classically-stable winding solitons in the two-higgs electroweak theory.

Kensuke Kusaka, Anthony G. Williams

The Bethe-Salpeter (BS) equation for scalar-scalar bound states in scalar theories without derivative coupling is formulated and solved in Minkowski space. This is achieved using the perturbation theory integral representation (PTIR), which allows these amplitudes to be expressed as integrals over weight functions and known singularity structures and hence a

Masako Iwasaki, Eiichi Nakano, Ryoji Enomoto

We present an electron-identification method using the time-projection chamber and the lead-glass calorimeter in the TOPAZ detector system. Using this method we have achieved good electron identification against hadron backgrounds over a wide momentum range in the hadronic events produced by both single-photon exchange and two-photon processes. Pion-rejectio

Jesus Inarrea, Gloria Platero

We have analyzed theoretically the effect of a laser on the tunneling current through a double barrier in the presence of a parallel magnetic field. The mag netotunneling current is modified by the light due to the photon emission and absorption processes which assist the tunneling of electrons through the struc ture. We observe that the effect of the light

Martin Howard, John Cardy

We consider the properties of the diffusion controlled reaction A+B->0 in the steady state, where fixed currents of A and B particles are maintained at opposite edges of the system. Using renormalisation group methods, we explicitly calculate the asymptotic forms of the reaction front and particle densities as expansions in (JD^{-1}|x|^{d+1})^{-1}, where J a

Jukka A. Ketoja, Indubala I. Satija

A renormalization scheme is developed to study an anisotropic quantum XY spin chain in a quasiperiodic transverse field. The critical phase of the quasi-particle excitations of the model with fractal wave functions exists in a finite parameter interval and is sandwiched between the extended and localized phases. The scaling properties of the critical phase f

Jukka A. Ketoja, Indubala I. Satija, Juan Carlos Chaves

A decimation method is applied to the tight binding model describing the two dimensional electron gas with next nearest neighbor interaction in the presence of an inverse golden mean magnetic flux. The critical phase with fractal spectrum and wave function exists in a finite window in two-dimensional parameter space. There are special points on the boundarie

T. Jungwirth, L. Smrcka

A detailed analysis of the capacitance of gated GaAs/AlGaAs heterostructures is presented. The nonlinear dependence of the capacitance on the gate voltage and in-plane magnetic field is discussed together with the capacitance quantum steps connected with a population of higher 2D gas subbands. The results of full self-consistent numerical calculations are co

D. A. Ivanov, Hyunwoo Lee, L. S. Levitov

We study counting statistics of electric current pumped by pulses of an external field. The fluctuations depend on the pulse shape, and can be minimized by choosing the pulse shape properly. For an optimal pulse shape, the fluctuations are reduced to the {\it dc} level, i.e., they do not depend on the duty cycle of the signal. We develop an approach that all

Xiangdong Shi

Observations show that there is significant clustering of QSO metal absorption lines within the range of velocity dispersion between 200km/sec and 600 km/sec. With a reasonable supernova rate, it is shown that high velocity gases driven by SNe and/or strong stellar winds could explain the clustered absorptions, provided that QSO metal-line absorbers are gala

Jaan Pelt, Rainer Kayser, Sjur Refsdal, Thomas Schramm

We present a new analysis of the presently available photometric data for the gravitationally lensed quasar 0957+561 A,B with the aim of determining the time delay between its two images. The basic method used is the dispersion estimation technique. Even by using the simplest non-parametric form of our method we can convincingly rule out a time delay near 53

P. Duffy, Lewis Ball, J. G. Kirk

The observations of radio emission from SNR~1987A can be accounted for on the basis of diffusive shock acceleration of electrons by the supernova blast wave. However, with this interpretation the observed spectral index implies that the compression ratio of the gas subshock is roughly $2.7$ rather than the value of $4$ expected of a strong shock front. We pr

Dany Page

Surface thermal emission has been detected by ROSAT from four nearby young neutron stars. Assuming black body emission, the significant pulsations of the observed light curves can be interpreted as due to large surface temperature differences produced by the effect of the crustal magnetic field on the flow of heat from the hot interior toward the cooler surf

M. J. Duff

On compactification to six spacetime dimensions, the fundamental heterotic string admits as a soliton a dual string whose effective worldsheet action couples to the background fields of the dual formulation of six-dimensional supergravity. On further toroidal compactification to four spacetime dimensions, the dual string acquires an $O(2,2;Z)$ target-space d

O. Derzhko, T. Krokhmalskii

A numerical approach to the study of equilibrium statistical properties of spin-1/2 XY chains is suggested. The approach is illustrated by the examining of influence of disorder on transverse dynamical susceptibility of spin-1/2 Ising chain in random transverse field.

S. M. H. Wong

Following the successful construction of the finite T real-time formalism in temporal axial gauge, we attempt to further study the equivalent new imaginary-time formalism of James and Landshoff based on the same Hamiltonian approach in the hope that it will provide the answer to Debye screening in QCD. It turns out that, unlike in the real-time case, energy

M. Bertini, M. Giffon, E. Predazzi

We show that one single Pomeron compatible with the Froissart limit, can account for all the present HERA data.

Ashish Mahabal, Ajit Kembhavi, ; K. P. Singh, P. N. Bhat

We present broad band surface photometry of the radio galaxy 3C270 (NGC~4261). We find a distinct dust lane in the $V-R$ image of the galaxy, and determine its orientation and size. We use the major axis profile of the galaxy to estimate the optical depth of the dust lane, and discuss the significance of the lane to the shape of the galaxy.

Anni Koubek

A method to determine the full structure of the space of local operators of massive integrable field theories, based on the form factor bootstrap approach is presented. This method is applied to the integrable perturbations of the Ising conformal point. It is found that the content of local operators can be expressed in terms of fermionic sum representations

Masayuki TANIMOTO

The supersymmetric extension of charged point particle&#39;s motion is applied to investigate symmetries of gravitational fields and electromagnetic fields. We mainly focus on the role of the Killing- Yano tensors of both usual and generalized types. Results obtained by systematic analysis strengthen the connection of the Killing- Yano tensor and superinvari

Timm Plefka

Based on the dissipative Landau-Lifshitz equation, the spatiotemporal structure formation problem is investigated in the region far above the transverse ferromagnetic resonance instability. Apart from the external fields, the model contains an isotropic exchange field, a shape demagnetisation field and an anisotropy field. Numerical simulations exhibit in th

Stefan Müller-Stach

Let X be a smooth projective variety of dimension n. If $p+q=n+1$ then Bloch has defined a ${\bf G}_m$-biextension E over the product of the Chow groups $CH^p_0(X)$ and $CH^q_0(X)$ of homologically trivial cycles. We prove that E is the pullback of the Poincare biextension over the product of intermediate Jacobians in characteristic zero. This is used to stu

E. Branchini, M. Plionis

Starting from the observed distribution of galaxy clusters in redshift space we use a two--step procedure to recover their distances and peculiar velocities. After statistically correcting for the unobserved cluster distribution in the zone of avoidance ($|b|\le 20^{\circ}$) and also for a smooth absorption at higher $|b|$&#39;s, we use a dynamical iterative

H. B. O&#39;Connell, B. C. Pearce, A. W. Thomas, A. G. Williams

We review the current status of rho-omega mixing and discuss its implication for our understanding of charge-symmetry breaking. In order to place this work in context we also review the photon-hadron coupling within the framework of vector meson dominance. This leads naturally to a discussion of the electromagnetic form-factor of the pion and of nuclear shad

S. De Martino, S. De Siena, F. Illuminati

We show that generalized coherent states follow Schrödinger dynamics in time-dependent potentials. The normalized wave-packets follow a classical evolution without spreading; in turn, the Schrödinger potential depends on the state through the classical trajectory. This feedback mechanism with continuous dynamical re-adjustement allows the packets to remain c

Lajos Diosi

We discuss both the restricted path integral (RPI) and the wave equation (WE) techniques in the theory of continuous quantum measurements. We intend to make Mensky&#39;s fresh review complete by transforming his &#34;effective&#34; WE with complex Hamiltonian into Ito-differential equations.

P. Mankiewicz, Nicole Tomczak-Jaegermann

Several characterizations of weak cotype 2 and weak Hilbert spaces are given in terms of basis constants and other structural invariants of Banach spaces. For finite-dimensional spaces, characterizations depending on subspaces of fixed proportional dimension are proved.

P. K. Lin

Let $X$ be a three dimensional real Banach space. Benítez and Otero \cite {BeO} showed that if the unit ball of $X$ is is an intersection of two ellipsoids, then every 2-polynomial defined in a linear subspace of $X$ can be extended to $X$ preserving the norm. In this article, we extend this result to any finite dimensional Banach space.

N. Asmar, Stephen J. Montgomery-Smith

Let $Σ$ be a $σ$-algebra over $Ω$, and let $M(Σ)$ denote the Banach space of complex measures. Consider a representation $T_t$ for $t\in\Bbb R$ acting on $M(Σ)$. We show that under certain, very weak hypotheses, that if for a given $μ\in M(Σ)$ and all $A \in Σ$ the map $t \mapsto T_t μ(A)$ is in $H^\infty(\Bbb R)$, then it follows that the map $t \mapsto T_t

G. S. Danilov

The method of the calculation of the multi-loop superstring amplitudes is proposed. The amplitudes are calculated from the equations that are none other than Ward identities. They are derived from the requirement that the discussed amplitudes are independent from a choice of gauge of both the vierbein and the gravitino field. The amplitudes are calculated in

A. Koubek

The space of local operators in massive deformations of conformal field theories is analysed. For several model systems it is shown that one can define chiral sectors in the theory, such that the chiral field content is in a one-to-one correspondence with that of the underlying conformal field theory. The full space of operators consists of the descendent sp

V. I. Matveev, M. M. Musakhanov, D. U. Matrasulov

Dirac equation for the finite dipole potential is solved by the method of the join of the asymptotics. The formulas for the near continuum state energy term of a relativistic electron-dipole system are obtained analytically. Two cases are considered: $Z < 137$ and $Z >137$

I. G. Avramidi, R. Schimming

The heat kernel coefficients $H_k$ to the Schrödinger operator with a matrix potential are investigated. We present algorithms and explicit expressions for the Taylor coefficients of the $H_k$. Special terms are discussed, and for the one-dimensional case some improved algorithms are derived.

F. M. C. Witte, S. P. Klevansky

Off-shellness and inhomogeneities are in the non-equilibrium dynamics of the lambda phi^4 model are studied using the closed timepath formalism reformulated as kinetic field theory. We take into account initial correlations up to the 4-point functions. The model is shown to exhibit a SO(1,1) symmetry broken by interactions and initial conditions. The diverge

M. Blasone, G. Vitiello

The fermion mixing transformations are studied in the quantum field theory framework. In particular neutrino mixing is considered and the Fock space of definite flavor states is shown to be unitarily inequivalent to the Fock space of definite mass states. The flavor oscillation formula is computed for two and three flavors mixing and the oscillation amplitud

Thomas G. Rizzo

Present and future prospects for the discovery of new gauge bosons, $Z&#39;$ and $W&#39;$, are reviewed. Particular attention is paid to hadron and $e^+e^-$ collider searches for the $W&#39;$ of the Left-Right Symmetric Model. (Presented at the {\it Fourth International Conference on Physics Beyond the Standard Model}, Lake Tahoe, CA, December 13-18, 1994.)

Kenneth Lane

Because of the top quark&#39;s very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the best probe of this physics until the Large Hadron Collider turns on in the next century. I discuss aspects of the mass and angular distributions that can be measured in $\ttb$

M. Shmatikov

The existence of hadronic molecular-type hybrids consisting of a baryon and a meson is argued. Long-range interactions due to one-pion exchange is shown to be strong enough to produce a loosely bound state. Specific features of a molecular hybrid are discussed.

X. Wang, J. Lopez, D. Nanopoulos

We compute the supersymmetric contribution to $R_{b}\equiv Γ(Z\to b{\bar b})/Γ(Z\to {\rm hadrons})$ in a variety of supergravity models. We find $R^{\rm susy}_b\lsim0.0004$, which does not shift significantly the Standard Model prediction ($R^{\rm SM}_b=0.2162$ for $m_t=160\GeV$). An improvement in experimental precision by a factor of four would be required

M. Gourdin, Y. Y. Keum, X. Y. Pham

We show that the factorization assumption in color-suppressed $B$ meson decays is not ruled out by experimental data on $B \ra K(K^*) + J/Ψ(Ψ^{&#39;})$. The problem previously pointed out might be due to an inadequate choice of hadronic form factors. Within the Isgur-Wise SU(2) heavy flavor symmetry framework, we search for possible $q^2$ dependence of form

S. Willenbrock

I examine the possibility that the electroweak interaction breaks itself via the condensation of fermions in large representations of the weak SU(2)_L gauge group.

K. Huitu, J. Maalampi, M. Raidal

The basics of a supersymmetric left-right model are reviewed. The production and subsequent decays of the doubly charged triplet higgsino $ \tildeΔ^{\pm\pm}$ in the Next Linear Collider are discussed. The slepton pair production in the framework of this model is also analysed.

M. J. Gibbs

Previous calculations of instanton effects in electroweak theory have concentrated on the case of zero Weinberg angle $θ_w$, where the U(1) hypercharge field decouples. In this paper we extend the instanton calculation to non-zero $θ_w$, by constructing a perturbation expansion. This allows for the first time the study of photon production at B and L number

Axel de la Macorra

We study the possibility of canceling the cosmological constant in supergravity string models. We show that with a suitable choice of superpotential the vacuum energy may vanish with the dilaton field at its minimum and supersymmetry broken with a large hierarchy. We derive the condition for which the introduction of a chiral potential, e.g. the inflaton pot

Kenneth Lane

Technicolor, with extended technicolor, is the theory of dynamical electroweak and flavor symmetry breaking at energies far below the Planck scale. To motivate it, I describe the most important difficulties of the standard electroweak model of symmetry breaking by elementary scalar bosons. I then tell how technicolor deals with these difficulties in a way th