July 1997 arXiv papers

Emidio Gabrielli, Uri Sarid

The inclusive branching ratio $B \to X_sγ$ and the anomalous magnetic moment $g_μ-2$ of the muon are accurately calculated within a minimal gauge-mediated SUSY-breaking model which naturally generates a large $\tanβ$. The predictions are in somewhat better agreement with current experiments, and new data will soon critically test these predictions. Predictio

Stanley J. Brodsky, Patrick Huet

We investigate properties of the color space of $SU(N_c)$ gauge theories in the limit of small number of colors $(N_c \to 0)$ and large number of flavors. More generally, we introduce a rescaling of $α_s$ and $n_f$ which assigns a finite limit to colored quantities as $N_c \to 0$, which reproduces their known large-$N_c$ limit, and which expresses them as an

Hooman Davoudiasl, Krishna Rajagopal, Eric Westphal

We describe a new mechanism for the generation of the baryon asymmetry of the universe during a first order electroweak phase transition. The mechanism requires the existence of two (or more) baryon number carrying scalar fields with masses and CP violating mixing which vary with the Higgs field expectation value. This mechanism can be implemented using squa

J. De Jaegher, B. de Wit, B. Kleijn, S. Vandoren

We give a detailed analysis of pairs of vector and hypermultiplet theories with N=2 supersymmetry in four spacetime dimensions that are related by the (classical) mirror map. The symplectic reparametrizations of the special Kähler space associated with the vector multiplets induce corresponding transformations on the hypermultiplets. We construct the Sp(1)$\

Nick Evans, Steve Hsu, Myck Schwetz

Supersymmetric Yang Mills theory is directly accessible to lattice simulations using current methodology, and can provide a non-trivial check of recent exact results in SQCD. In order to tune the lattice simulation to the supersymmetric point it is neccessary to understand the behavior of the theory with a small supersymmetry breaking gaugino mass. We introd

James M. Turner

We propose a generalization of a conjecture of D. Quillen, on the vanishing of André-Quillen homology, to simplicial commutative rings. This conjecture characterizes a notion of local complete intersection, extended to the simplicial setting, under a suitable hypothesis on the local characteristic. Further, under the condition of finite-type homology, we the

Eric V. Linder

Distance relations in a locally inhomogeneous universe are expected to behave like the Dyer-Roeder solution on small angular scales and the Friedmann-Robertson-Walker solution on large angular scales. Within a simple compact clump model the transition between these asymptotic behaviors is demonstrated and quantified. The redshift dependent transition scale i

J. A. Grifols, E. Masso, R. Toldra

We reanalyse the limits on the gravitino mass $m_{3/2}$ in superlight gravitino scenarios derived from arguments on energy-loss during gravitational collapse. We conclude that the mass range $10^{-6}eV\leq m_{3/2}\leq2.3\times10^{-5}eV$ is excluded by SN1987A data. In terms of the scale of supersymmetry breaking $Λ$, the range $70GeV\leqΛ\leq 300GeV$ is not

Jaume Guasch, Joan Sola

From the tau-lepton analysis of the charged Higgs decay of the top quark at the Tevatron, t -> H+ b -> tau+ nu_{tau} b, it is possible to set rather stringent bounds on the (tan(beta),M_{H+})-plane, if one assumes that H+ is a charged member of a generic two-Higgs-doublet model. However, if we consider the possibility that H+ is supersymmetric, then we find

Savas Dimopoulos, Gia Dvali, Riccardo Rattazzi

In this paper two things are done. First, we propose a simple model of dynamical gauge-mediated SUSY breaking. This model incorporates a dynamical relaxation mechanism which solves the μ-problem with no light fields beyond those of the MSSM. In the second part of the paper we show how this mechanism is generalized and give two more examples in which it is in

Olivier Parcollet, Antoine Georges

A novel large-N limit of the multichannel Kondo model is introduced, for representations of the impurity spin described by Schwinger bosons. Three cases are found, associated with underscreening, overscreening and exact Kondo screening of the impurity. The saddle-point equations derived in this limit are reminiscent of the ``non-crossing approximation'&#

Pascal Lederer, PUC-Rio, UFRJ, Physique des Solides

The Ultra Quantum Crystal phases observed in quasi-one-dimensional conductors of the Bechgaard salts family under magnetic field exhibit both Spin Density Wave order and a Quantized Hall Effect. As a result, they also possess a Magneto-Roton mode within the single particle gap, and the usual Goldstone modes. The sign reversals of the Quantum Hall Effect have

Ralph H. France, Moshe Gai

We dispute the alteration by Azuma et al. of the energy calibration of the Mainz('71) data on the beta-delayed alpha-particle emission of $^{16}N$ as well as the very justification of the recalibration. We use the unaltered data to observe a pronounced disagreement between the TRIUMF('94) and Mainz('71) data sets on both the high and low energy s

J. A. Grifols, E. Masso, R. Toldra

We consider lepton-quark contact interactions in models with right-handed neutrinos, and find that observational data from SN1987A restricts the scale of such interactions to be at least $Λ>90$ TeV.

Yu. L. Dokshitzer, A. Lucenti, G. Marchesini, G. P. Salam

We address the problem of potential non-universality of the leading 1/Q power corrections to jet shapes emerging from the non-inclusive character of these observables. We consider the thrust distribution as an example and analyse the non-inclusive contributions which emerge at the two-loop level. Although formally subleading in $\as$, they modify the existin

S. Mao, H. J. Mo

Galaxies can be classified in two broad sequences which are likely to reflect their formation mechanism. The `main sequence', consisting of spirals, irregulars and all dwarf galaxies, is probably produced by gas settling within dark matter haloes. We show that the sizes and surface densities along this sequence are primarily determined by the distributio

S. A. Gardiner, J. I. Cirac, P. Zoller

We propose an experimental configuration, within an ion trap, by which a quantum mechanical delta-kicked harmonic oscillator could be realized, and investigated. We show how to directly measure the sensitivity of the ion motion to small variations in the external parameters.

Toshio Nakatsu, Kazutoshi Ohta, Takashi Yokono, Yuhsuke Yoshida

Higgs branch of N=2 SQCD is studied from the M theory viewpoint. With a differential geometrical proof of the s-rule besides an investigation on the global symmetry of M theory brane configurations, an exact description of the baryonic and non-baryonic branches in terms of M theory is presented. The baryonic branch root is also studied. The ``electric'&#

Hiroshi Kuratsuji, Shouhei Kakigi

By starting with the Maxwell theory of electromagnetism, we study the change of polarization state of light transmitting through optically anisotropic media. The basic idea is to reduce the Maxwell equation to the Schroedinger like equation for two levels (or states) representing polarization. By using the quantum mechanical technique, the density matrix, an

Keiichi Akama, Takashi Hattori

We derive and solve the compositeness condition for the SU(N_c) gauge boson at the next-to-leading order in 1/N_f (N_f is the number of flavors) and the leading order in ln(Λ^2) (Λis the compositeness scale) to obtain an expression for the gauge coupling constant in terms of the compositeness scale. It turns out that the argument of gauge-boson compositeness

Sung-Soo Kim, Phillial Oh, Chaiho Rim

We perform the dimensional reduction of the nonrelativistic CP(1) model coupled to an Abelian Chern-Simons gauge field in the self-dual limit, and investigate the soliton and domain wall solutions of the emerging 1+1 dimensional self-dual spin system. This system is described by inhomogeneous Landau-Lifshitz system with an extra non-local term. The Hamiltoni

Chao-Shang Huang, Hua-Gang Yan

The inclusive rate and $τ$ spectrum for a polarized $Λ_b$ -baryon to decay to charm hadronic final states and leptons $τν$ in the SM and a two-Higgs doublet model are computed.The $O(α_s)$ QCD corrections to $τ$ spectrum in the two-Higgs model are also given.

George Wei-Shu Hou

Two down-up perspectives on quark mass-mixing relations are reviewed. The modified Fritzsch path relates $V_{cb}$ and $V_{ub}$ to $M_u$, but has trouble with the low $V_{cb} \simeq 0.04$ value. The modified Wolfenstein path focuses on the change in $V_{ub}$ from $λ^3 { (ca. 1983)} \leadsto λ^4 { (ca. 1994)}$. The relations $m_d/m_s\sim m_s/m_b \sim δ\sim λ^2

George Wei-Shu Hou

We briefly review the phenomenology of FCNC, from the very rare $μ/K$, through the medium $b$, to the "pseudo-well-done" case of $b'$, extending to the possibility of large tree level FCNC at weak scale.

George Wei-Shu Hou

We argue that the $1^{--}$ glueball $O$ is much cleaner than other glueball candidates. Anomalously large $J/ψ\to ρπ, K^*\bar K$ decays and the scalar glueball mass scale suggest that $m_{O} \simeq m_{J/ψ}$.

Lev Vaidman, Ori Belkind

An inequality, recently proposed by Franson [Phys. Rev. A 54, 3808 (1996)] is analyzed and improved. The inequality connects the change of the expectation value of an observable with the uncertainty of this observable. A strict bound on the ratio between these two quantities is obtained.

A. Fring, V. Kostrykin, R. Schrader

We continue our investigation concerning the question of whether atomic bound states begin to stabilize in the ultra-intense field limit. The pulses considered are essentially arbitrary, but we distinguish between three situations. First the total classical momentum transfer is non-vanishing, second not both the total classical momentum transfer and the tota

T. Csorgo, J. Zimanyi

Brooding over pions, wave packets and Bose-Einstein correlations, we present a recently obtained analytical solution to a pion laser model, which may describe the final state of pions in high energy heavy ion collisions.

A. Holt, T. Engeland, M. Hjorth-Jensen, E. Osnes

We calculate the low-lying spectra of heavy tin isotopes from A=120 to A=130 using the 2s1d0g_{7/2}0h_{11/2} shell to define the model space. An effective interaction has been derived using 132Sn as closed core employing perturbative many-body techniques. We start from a nucleon-nucleon potential derived from modern meson exchange models. This potential is i

Emmanuel Kowalski, Philippe Michel

We study, on average over f, zeros of the L-functions of primitive weight two forms of level q (fixed). We prove, on the one hand, density theorems for the zeros (similar to the results of Bombieri, Jutila, Motohashi, Selberg in the case of characters), which are applied in \cite{KM} to obtain a sharp unconditionnal estimate of the (analytic) rank of the new

Emmanuel Kowalski, Philippe Michel

In this paper, we prove an unconditionnal bound for the analytic rank (i.e the order of vanishing at the critical point of the $L$ function) of the new part $J^n_0(q)$, of the jacobian of the modular curve $X_0(q)$. Our main resultis the following upper bound: for $q$ prime, one has $$rank_a(J_0^n(q))\ll \dim J_0^n(q)$$ where the implied constant is absolute

M. Chaves

We show that a system of bosons in a T=0 quantum field theory can present metastable ground states with spontaneous symmetry breaking, even in the absence of an imaginary mass term. This gives a natural explanation to the Davis-Shellard background field \exp(-i ω_0 t) and adds a new degree of freedom in boson systems, with possible applications in cosmology,

B. de Wit, K. Peeters, J. C. Plefka

The supersymmetry algebra for supermembranes, quantized in the light-cone gauge, exhibits central charges induced by wrapping the membrane around compact dimensions. These central charges are manifestly consistent with Lorentz symmetry. While the central charges raise the mass of the membrane states, they still leave the mass spectrum continuous, at least ge

Ilka Brunner, Andreas Karch

We give some evidence that the worldvolume theory of the M-theory KK 6-brane is governed by a non-critical membrane theory. We use this theory to give a matrix description of M-theory on $T^6$.

E. Elizalde

After recalling the precise existence conditions of the zeta function of a pseudodifferential operator, and the concept of reflection formula, an exponentially convergent expression for the analytic continuation of a multidimensional inhomogeneous Epstein-type zeta function of the general form ζ_{A,\vec{b},q} (s) = \sum_{\vec{n}\in Z^p (\vec{n}^T A \vec{n} +

L. Baulieu, C. Laroche, N. Ohta, M. Picco

Within a BRST formulation, we determine the expressions of the consistent anomaly for superstrings with extended worldsheet supersymmetries of rank N. We consider the O(N) superconformal algebras up to N=4, as well as the `small N=4' superalgebra. This is done using a superfield formalism, allowing to recover previous results that were expressed in compo

S. Boldyrev

The randomly driven Burgers equation with pressure is considered as a 1D model of strong turbulence of compressible fluid. It is shown that infinitely small pressure provides a finite effect on the velocity and density statistics and this case therefore is qualitatively different from turbulence without pressure. We establish the corresponding operator produ

H. D. Doebner, K. Lazarow, A. G. Ushveridze

We introduce a new concept of infinite quasi-exactly solvable models which are constructable through multi-parameter deformations of known exactly solvable ones. The spectral problem for these models admits exact solutions for infinitely many eigenstates but not for the whole spectrum. The hermiticity of their hamiltonians is guaranteed by construction. The

V. V. Nesterenko, I. G. Pirozhenko

A simple method for calculating the Casimir energy for a sphere is developed which is based on a direct mode summation and counter integration in a complex plane of eigenfrequencies. The method uses only classical equations determining the eigenfrequencies of the quantum field under consideration. Efficiency of this approach is demonstrated by calculation of

Gerhard Buchalla

We review basic aspects of the phenomenology of CP violation in the decays of $K$ and $B$ mesons. In particular we discuss the commonly used classification of CP violation -- CP violation in the mass matrix, in the interference of mixing with decay, and in the decay amplitude itself -- and the related notions of direct and indirect CP violation. These concep

Vernon Barger, Chung Kao, Ashok Das

The electric dipole moment of the muon ($d_μ$) is evaluated in a two Higgs doublet model with a softly broken discrete symmetry. For $\tanβ\equiv |v_2|/|v_1| \sim 1$, contributions from two loop diagrams involving the $t$ quark and the $W$ boson dominate; while for $\tanβ\gsim 10$, contributions from two loop diagrams involving the $b$ quark and the $τ$ lept

P. Bamert, C. P. Burgess, D. Michaud

Motivated by earlier calculations showing large effects when neutrinos propagate through fluctuating media, we perform here a detailed analysis of how density fluctuations in the sun in the form of helioseismic waves can modify the MSW solution to the solar neutrino problem. We find negligible effects for the MSW spectrum, even under extreme circumstances. T

Jose R. Espinosa

Potentially realistic string models often contain additional abelian gauge factors besides the standard model group. The consequences of such extended gauge structure are manifold both for theory and phenomenology as I show focussing in the simplest case of just one additional non-anomalous U(1)'. First, I discuss the possible symmetry breaking patterns

T. S. Evans, H. F. Jones, A. Ritz

We describe an application of the linear $\de$-expansion to the calculation of correlation functions in SU(2)-Higgs lattice gauge theory. A significant advantage of the technique is that an infinite volume lattice may be used, allowing the non-analyticity in certain observables at a phase transition to be observed directly. We illustrate the approach with a

A. Rebhan

Hard thermal loop effective actions furnish the building blocks of resummed thermal perturbation theory, which is expected to work as long as the quantities under consideration are not sensitive to the nonperturbative (chromo-)magnetostatic sector. A different breakdown of perturbation theory occurs whenever external momenta are light-like, because the hard

A. F. Krutov, V. E. Troitsky

The electromagnetic form factors of $π$ and $K$ mesons and deuteron are calculated in modified impulse approximation using instant form of relativistic Hamiltonian dynamics. The different model wave functions are used. Meson wave function parameters are fixed by fitting the mean square radius of meson. The internal quark structure is taken into account throu

A. F. Krutov, V. E. Troitsky

We present a relativistic treatment of the problem of soft electromagnetic structure by the modified instant form of relativistic Hamiltonian dynamics. Our approach uses relativistic parametrization and so picks out the relativistic invariant quantities on each stage of the calculation. The electromagnetic current matrix element satisfies the current conserv

Makoto Oka

The quark model description of the hyperon nucleon forces, especially the antisymmetric spin-orbit forces, is studied from the spin-flavor SU(6) and the flavor SU(3) symmetry point of view. It is pointed out that the quark exchange interaction predicts strong antisymmetric spin-orbit force between the hyperon and nucleon.

Martin C. Smith, T. Stelzer, S. Willenbrock

We show that the perturbation series for quarkonia energies diverges at large orders. This results in a perturbative ambiguity in the energy that scales as e^(-1/a*Lambda) where a is the Bohr radius of quarkonium and Lambda is the QCD scale parameter. This ambiguity is associated with a nonperturbative contribution to the energy from distances of order 1/Lam

Rajamani Narayanan

The overlap formula for the chiral determinant is presented and the realization of gauge anomalies and gauge field toplogy in this context is discussed. The ability of the overlap formalism to deal with supersymmetric theories and Majorana-Weyl fermions is outlined. Two applications of the overlap formalism are discussed in some detail. One application is th

K. Rummukainen

We study the phase diagram of the 3-dimensional SU(2) + adjoint Higgs theory, and investigate to what extent it can be used as an effective theory of the 4-dimensional high-T SU(2) QCD. The relation between the parameters in 4 and 3 dimensions is obtained through dimensional reduction. The high-T (deconfined) QCD phase corresponds to the symmetric phase of t

J. Peisa

We study the properties of the phase transition in three dimensional U(1)+Higgs theory or Ginzburg-Landau model of superconductivity. Special attention is paid to large values of scalar self coupling (Type II superconductors), where the nature of the transition is unclear. We present some evidence for an unusual transition in this regime.

Ryuji Suda et al

We have developed a Monte-Carlo simulation code for an aerogel \v Cerenkov Counter which is operated under a strong magnetic field such as 1.5T. This code consists of two parts: photon transportation inside aerogel tiles, and one-dimensional amplification in a fine-mesh photomultiplier tube. It simulates the output photoelectron yields as accurately as 5% wi

S. Berceanu

The transition amplitudes between coherent states on a coherent state manifold are expressed in terms of the embedding of the coherent state manifold into a projective Hilbert space. Consequences for the dimension of projective Hilbert space and a simple geometric interpretation of Calabi's diastasis follows.

S. Berceanu

The consequences for Berezin's quantization on symmetric spaces of the identity of the set of coherent vectors orthogonal to a fixed one with the cut locus are stated precisely. It is shown that functions expressing the coherent states, the covariant symbols of operators, the diastasis function, the characteristic and two-point functions are defined when one

Chris H. Wiggins, Raymond E. Goldstein

A stiff one-armed swimmer in glycerine goes nowhere, but if its arm is elastic, exerting a restorative torque proportional to local curvature, the swimmer can go on its way. Considering this happy consequence and the principles of elasticity, we study a hyperdiffusion equation for the shape of the elastica in viscous flow, find solutions for impulsive or osc

R. Leidl, H. W. Diehl

The surface critical behavior of bcc binary alloys undergoing a continuous B2-A2 order-disorder transition is investigated in the mean-field (MF) approximation. Our main aim is to provide clear evidence for the fact that surfaces which break the two-sublattice symmetry generically display the critical behavior of the NORMAL transition, whereas symmetry-prese

Satya N. Majumdar, Stephen J. Cornell

We study the the survival probability P(t) upto time t, of a test particle moving in a fluctuating external field. The particle moves according to some prescribed deterministic or stochastic rules and survives as long as the external field that it sees at its own location does not change sign. This is a natural generalization of the "static persistence&#

K. P. N. Murthy, K. W. Kehr

The ground state dynamics of an entropy barrier model proposed recently for describing relaxation of glassy systems is considered. At stages of evolution the dynamics can be described by a simple variant of the Ehrenfest urn model. Analytical expression for the relaxation times from an arbitrary state to the ground state is derived. Upper and lower bounds fo

L. A. N. Amaral, S. V. Buldyrev, S. Havlin, M. A. Salinger

We study the dynamics of a system composed of interacting units each with a complex internal structure comprising many subunits. We consider the case in which each subunit grows in a multiplicative manner. We propose a model for such systems in which the interaction among the units is treated in a mean field approximation and the interaction among subunits i

Alexander O. Gogolin, Alexander A. Nersesyan, Alexei M. Tsvelik, Lu Yu

The influence of nonmagnetic doping on the thermodynamic properties of two-leg S = 1/2 spin ladders is studied in this paper. It is shown that, for a weak interchain coupling, the problem can be mapped onto a model of random mass Dirac (Majorana) fermions. We investigate in detail the structure of the fermionic states localized at an individual mass kink (ze

M. R. Evans, Y. Kafri, H. M. Koduvely, D. Mukamel

A driven diffusive model of three types of particles that exhibits phase separation on a ring is introduced. The dynamics is local and comprises nearest neighbor exchanges that conserve each of the three species. For the case in which the three densities are equal, it is shown that the model obeys detailed balance. The Hamiltonian governing the steady state

C. Bulutay, M. Tomak

We draw attention to the past literature on valley phase transition in Si(100) MOSFETs. The recent experiments performed by Kravchenko and co-workers indicating metal-insulator transition in Si MOSFETs are also in accord with the valley phase transition mechanism.

W. Selke, F. Szalma, P. Lajko, F. Igloi

Ising models with nearest-neighbor ferromagnetic random couplings on a square lattice with a (1,1) surface are studied, using Monte Carlo techniques and star-tiangle transformation method. In particular, the critical exponent of the surface magnetization is found to be close to that of the perfect model, beta_s=1/2. The crossover from surface to bulk critica

G. Sierra, M. A. Martin-Delgado, J. Dukelsky, S. R. White

We present a variational treatment of the ground state of the 2-leg t-J ladder, which combines the dimer and the hard-core boson models into one effective model. This model allows us to study the local structure of the hole pairs as a function of doping. A second order recursion relation is used to generate the variational wave function, which substantially

Kingshuk Ghosh, Arnab Majumdar, Debashish Chowdhury

We report the first analytical calculation of the distribution of the time headways in some special cases of a particle-hopping model of vehicular traffic on idealized single-lane highways and compare with the corresponding results of our computer simulation. We also present numerical results for the time-headway distribution in more general situations in th

O. Zik, Z. Olami, E. Moses

A thin solid (e.g., paper), burning against an oxidizing wind, develops a fingering instability with two decoupled length scales. The spacing between fingers is determined by the Péclet number (ratio between advection and diffusion). The finger width is determined by the degree two dimensionality. Dense fingers develop by recurrent tip splitting. The effect

Assa Auerbach

The tunneling rate of fractional charge across a Laughlin state on the cylinder is computed numerically. The decay with strip width Y is fitted to exp[- a (Y/ l)**2/12] where l is the Landau length, and a is approximately 1.0. This rate is exponentially LARGER than the electron tunneling rate and can be interpreted by analogy to a superfluid vortex tunneling

Matthias Fuchs, Kenneth S. Schweizer

The predictions of the polymer mode coupling theory for the finite size corrections to the transport coefficients of entangled polymeric systems are tested in comparisons with various experimental data. It is found that quantitative descriptions of the viscosities, eta, dielectric relaxation time, tau_e, and diffusion coefficients, D, of polymer melts can be

Matthias Fuchs, Kenneth S. Schweizer

The transport coefficients of dense polymeric fluids are approximately calculated from the microscopic intermolecular forces. The following finite molecular weight effects are discussed within the Polymer-Mode-Coupling theory (PMC) and compared to the corresponding reptation/ tube ideas: constraint release mechanism, spatial inhomogeneity of the entanglement

Philip J. Armitage

I review theoretical aspects of the interaction between the accretion stream and the disk in interacting binary systems, concentrating on recent hydrodynamic calculations. At low accretion rates, cooling is expected to be efficient, and the interaction leads to a nearly ballistic stream overflowing the disk rim towards smaller radii. If cooling is ineffectua

M. Boettcher, H. -P. Reuter, H. Lesch

We present a model for the inverted radio spectra of active active galactic nuclei as well as the central regions of normal galaxies. The model is based on the unified scenario for active galaxies, stating that the central engines of active galaxies consists of a supermassive black hole surrounded by an accretion disk and a radio jet. The nuclei of normal (i

Paul A. Kimoto, David F. Chernoff

We discuss high-resolution simulations of one-dimensional, plane-parallel shock waves with mean speeds between 150 and 240 km/s propagating into gas with Alfven velocities up to 40 km/s and outline the conditions under which these radiative shocks experience an oscillatory instability in the cooling length, shock velocity, and position of the shock front. We

Norman K. Glendenning

Phase transitions in compact stars are discussed including hyperonization, deconfinement and crystalline phases. Reasons why kaon condensation is unlikely is reviewed. Particular emphasis is placed on the evolution of internal structure with spin-down of pulsars. A signature of a first order phase transition in the timing structure of pulsars which is strong

Antonio Parravano, Catherine Pech

The variation of an ionizing flux as a mechanism to stimulate the condensation of a diffuse gas is considered. To illustrate this effect, two situations are examined: one on the context of pregalactic conditions, and the other on the context of the actual interstellar medium. We focus our attention on flash-like variations; that is, during a ``short'&#39

M. Colpi

We study the dynamical evolution of a satellite orbiting outside of a companion spherical galaxy. The satellite is subject to a back-reaction force resulting from the density fluctuations excited in the primary stellar system. We evaluate this force using the linear response theory developed in Colpi and Pallavicini (1997). The force is computed in the refer

M. Colpi, A. Pallavicini

We derive a formalism, within the theory of linear response, for the analysis of the interaction of a satellite (the perturber) with a spherical galaxy whose equilibrium is described by a one-particle distribution function. We compute the formal expression of the force on the satellite including the self-gravity of the stars and the shift of the stellar cent

Prasenjit Saha, Liliya L. R. Williams

We describe a new, non-parametric, method for reconstructing lensing mass distributions in multiple-image systems, and apply it to PG1115, for which time delays have recently been measured. It turns out that the image positions and the ratio of time delays between different pairs of images constrain the mass distribution in a linear fashion. Since observatio

O. Lahav, N. Brosch, E. Goldberg, G. K. T. Hau

Motivated by recent discoveries of nearby galaxies in the Zone of Avoidance, we conducted a pilot study of galaxy candidates at low Galactic latitude, near Galactic longitude $l \sim 135^0$, where the Supergalactic Plane is crossed by the Galactic Plane. We observed with the 1m Wise Observatory in the I-band 18 of the `promising' candidates identified by

A. Burkert, J. Silk

The best measured rotation curve for any galaxy is that of the dwarf spiralXXXX DDO 154, which extends out to about 20 disk scale lengths. It provides an ideal laboratory for testing the universal density profile prediction from high resolution numerical simulations of hierarchical clustering in cold dark matter dominated cosmological models. We find that th

I. G. Mitrofanov

The paper presents the nowdays definition of the phenomenon of cosmic gamma ray bursts, refers to the main alternative models of their origin and proposes three promising domains of new observations in the incoming decade.

A. Hirschowitz, S. Ramanan

We prove that two weakened forms of Green's conjectures for canonical curves are equivalent when the genus $g$ is odd.

G. D. Lythe

We consider a slow passage through a point of loss of stability. If the passage is sufficiently slow, the dynamics are controlled by additive random disturbances, even if they are extremely small. We derive expressions for the `exit value' distribution when the parameter is explicitly a function of time and the dynamics are controlled by additive Gaussia

G. D. Lythe

A parabolic stochastic PDE is studied analytically and numerically, when a bifurcation parameter is slowly increased through its critical value. The aim is to understand the effect of noise on delayed bifurcations in systems with spatial degrees of freedom. Realisations of the nonautonomous stochastic PDE remain near the unstable configuration for a long tim

Mans Henningson, Piljin Yi

We consider the realization of four-dimensional theories with N = 2 supersymmetry as M-theory configurations including a five-brane. Our emphasis is on the spectrum of massive states, that are realized as two-branes ending on the five-brane. We start with a determination of the supersymmetries that are left unbroken by the background metric and five-brane. W

Eddy Timmermans, Paolo Tommasini

We present a Thomas-Fermi treatment of resonant incoherent scattering of low-intensity light by a dilute spatially confined Bose-Einstein condensate. The description gives simple analytical results and allows scattering data from finite-size condensates to be interpreted in terms of the properties of the homogeneous BEC-system. As an example, we show how the

David Kaiser

We extend recent work on the resonance structure for post-inflation reheating, providing an analytic treatment for models in which both the inflaton and the fields into which it decays are massless. Solutions are derived which are valid for either a spatially-flat or spatially-open metric. Closed-form solutions are given for the characteristic exponent, whic

Mark B. Wise

Applications of effective field theory to nucleon-nucleon scattering, quarkonia decay and production and B meson decay are discussed. Some unresolved issues are considered.

H. T. Freudenreich

A model of the bar and old stellar disk of the Galaxy has been derived from the survey of the Diffuse Infrared Background Experiment (DIRBE) of the Cosmic Background Explorer at wavelengths of 1.25, 2.2, 3.5, and 4.9 microns. It agrees very well with the data, except in directions in which the near- infrared optical depth is high. Among the conclusions drawn

Amol S. Dighe, Michael Gronau, Jonathan L. Rosner

The observation by the CLEO Collaboration of the decays $B^{(+,0)} \to K^{(+,0)} η'$ is shown to imply a significant but still uncertain contribution from the flavor-SU(3)-singlet component of the $η'$. By comparing the rate for these decays with others for decays of B mesons to two pseudoscalar mesons, it is shown that the prospects for observing CP

Israel Gelfand, Vladimir Retakh, M. Shubin

In this paper we study geometry of symmetric torsion-free connections which preserve a given symplectic form

Alain Comtet, Christophe Texier

We consider a one-dimensional model of localization based on the Witten Hamiltonian of supersymmetric quantum mechanics. The low energy spectral properties are reviewed and compared with those of other models with off-diagonal disorder. Using recent results on exponential functionals of a Brownian motion we discuss the statistical properties of the ground st

Gyuri Wolf, Bengt Friman, Madeleine Soyeur

An $ω$-meson in motion with respect to a nuclear medium can couple to a $σ$-meson through a particle-hole excitation. This coupling is large. We investigate its consequences for the width of $ω$-mesons in matter and for the s-wave annihilation of pions into lepton pairs which can take place in relativistic heavy ion collisions. We find that the two pion deca

Alfredo Vázquez-Cruz

In this thesis we are interested in the study of the gravitational properties of quantum bosonic strings. We start by computing the quantum energy-momentum tensor ${\hat T}^{μν}(x)$ for strings in Minkowski space-time. We perform the calculation of its expectation value for different physical string states both for open and closed bosonic strings. The states

Vito Latora, Andrea Rapisarda, Stefano Ruffo

We study the largest Lyapunov exponent $λ$ and the finite size effects of a system of N fully-coupled classical particles, which shows a second order phase transition. Slightly below the critical energy density $U_c$, $λ$ shows a peak which persists for very large N-values (N=20000). We show, both numerically and analytically, that chaoticity is strongly rel

Soonkeon Nam, Kyungho Oh, Sang-Jin Sin

We consider brane configurations in M-theory describing N=1 supersymmetric gauge theories and using the parametric representation of the brane configurations, we calculate the superpotentials for various cases including multiple gauge groups or fermions. For SU(n) N=1 SQCD with $N_f$ fermion case ($N_f < N_c)$, we find that the superpotential from M-theory a

D. V. Antonov

The effective string theory emerging from the bilocal approximation to the Method of Vacuum Correlators in gluodynamics is shown to be well described by the 4D theory of the massive Abelian Kalb-Ramond field interacting with the string, which is known to be the low-energy limit of the Universal Confining String Theory. This correspondence follows from the ag

J. S. Bagla, S. Engineer, T. Padmanabhan

It is known that radial collapse around density peaks can explain the key features of evolution of correlation function in gravitational clustering in three dimensions. The same model also makes specific predictions for two dimensions. In this paper we test these predictions in two dimensions with the help of N-Body simulations. We find that there is no stab

Xue-Bing Wu

The effects of radial advection and thermal diffusion were considered in investigating the linear stability of an optically thin, two-temperature accretion disc. If the disc has only very little advection, we proved that the thermal instability exists when the disc is geometrically thin. But it dispears in a geometrically slim disc if the thermal diffusion w

Ola Tornkvist

Magnetic fields may have been generated in the electroweak phase transition through spontaneous symmetry breaking or through the subsequent dynamical evolution of semiclassical field configurations. Here I demonstrate explicitly how magnetic fields emerge spontaneously in the phase transition also when no gradients of the Higgs field are present. Using a sim