October 1996 arXiv papers — page 5

W. Hollik

This talk summarizes the status of the standard model predictions for electroweak precision observables including g-2 for muons, and discusses the status of the standard model and the MSSM in view of the new data.

Juan Garcia-Bellido, Andrew R Liddle

We study the phenomenological constraints on a recently proposed model of open inflation in the context of induced gravity. The main interest of this model is the relatively small number of parameters, which may be constrained by many different types of observation. We evaluate the complete spectrum of density perturbations, which contains continuum sub-curv

Farhad Ardalan, Amir H. Fatollahi

Dynamics of a free point particle on a multi world-line is presented and shown to reduce to that of a bosonic string theory at the appropriate limit. Other higher dimensional extended objects are argued to appear at other regions of the space of configurations of the theory.

Lajos Diosi

The convenience of coherent state representation is discussed from the viewpoint of what is in a broad sense called the measurement problem in quantum mechanics. Standard quantum theory in coherent state representation is intrinsically related to a number of earlier concepts conciliating quantum and classical processes. From a natural statistical interpretat

Doochul Kim

The Bethe ansatz equation is solved to obtain analytically the leading finite-size correction of the spectra of the asymmetric XXZ chain and the accompanying isotropic 6-vertex model near the antiferromagnetic phase boundary at zero vertical field. The energy gaps scale with size $N$ as $N^{-1/2}$ and its amplitudes are obtained in terms of level-dependent s

Mohan Rajagopal, Roger W. Romani, M. Coleman Miller

Using a Hartree-Fock formalism, we estimate energy levels and photon cross sections for atomic iron in magnetic fields B ~ 10^13 G. Computing ionization equilibrium and normal mode opacities with these data, we construct LTE neutron star model atmospheres at 5.5 < Log(T_eff) < 6.5 and compute emergent spectra. We examine the dependence of the emergent spectr

T. Schaefer, E. Shuryak

We review the theory and phenomenology of instantons in QCD. After a general overview, we provide a pedagogical introduction to semi-classical methods in quantum mechanics and field theory. The main part of the review summarizes our understanding of the instanton liquid in QCD and the role of instantons in generating the spectrum of light hadrons. We also di

Masaki Oshikawa, Masanori Yamanaka, Ian Affleck

We discuss zero-temperature quantum spin chains in a uniform magnetic field, with axial symmetry. For integer or half-integer spin, $S$, the magnetization curve can have plateaus and we argue that the magnetization per site $m$ is topologically quantized as $q (S - m)= integer$ at the plateaus, where $q$ is the period of the groundstate. We also discuss cond

M. Fortunato, G. Kurizki, W. P. Schleich

By sending many two-level atoms through a cavity resonant with the atomic transition, and letting the interaction times between the atoms and the cavity be randomly distributed, we end up with a predetermined Fock state of the electromagnetic field inside the cavity if we perform after the interaction with the cavity a conditional measurement of the internal

Denis V. Juriev

This short paper being devoted to some aspects of the inverse problem of the representation theory briefly treats the interrelations between the author&#39;s approach to the setting free of hidden symmetries and the researches of D.P.Zhelobenko in the generalized Mickelsson algebras and related topics.

P. T. Landsberg, G. E. A. Matsas

Using the Unruh-DeWitt detector, it is shown that a universal and continuous Lorentz transformaion of temperature cannot exist for black-body radiation. Since any valid Lorentz transformation of temperature must be able to deal with black-body radiation, it is concluded that a universal and continuous temperature transformation does not exist.

K. Nakanishi, K. Itoh, Y. Igarashi, M. Bando

In the Optimal Velocity Model proposed as a new version of Car Following Model, it has been found that a congested flow is generated spontaneously from a homogeneous flow for a certain range of the traffic density. A well-established congested flow obtained in a numerical simulation shows a remarkable repetitive property such that the velocity of a vehicle e

A. Makhlin, E. Surdutovich, G. Welke

Interferometry is discussed in terms of the representation of the source. In particular, scale-invariant 1-d hydrodynamics is revisited, and extended to the case of unequal transverse masses. It is argued that that kaon emission occurs over a short time interval. Exact results for models of two- and three-dimensional flow are presented, which exhibit altered

L. A. Winckelmann, S. A. Bass, M. Bleicher, M. Brandstetter

The behavior of hadronic matter at high baryon densities is studied within Ultrarelativistic Quantum Molecular Dynamics (URQMD). Baryonic stopping is observed for Au+Au collisions from SIS up to SPS energies. The excitation function of flow shows strong sensitivities to the underlying equation of state (EOS), allowing for systematic studies of the EOS. Effec

K. Rutz, M. Bender, T. Buervenich, T. Schilling

The shell structure of superheavy nuclei is investigated within various parametrizations of relativistic and nonrelativistic nuclear mean field models. The heaviest known even-even nucleus 264Hs is used as a benchmark to estimate the predictive value of the models. From that starting point, doubly magic spherical nuclei are searched in the region Z=110-140 a

Michael Harris, Jacques Tilouine

Let p be a prime number, and let f, g, and h be three modular forms of weights $κ$, $λ$, and $μ$ for $SL(2,\Bbb{Z})$. We suppose $κ\geq λ+ μ$. In joint work with Kudla, one of the authors obtained a formula for the normalized {\it square root} of the value at $s = {1/2}(κ+ λ+ μ- 2)$ (the {\it central critical value}) of the triple product $L(s,f,g,h)$. We ap

R. Parthasarathy, K. S. Viswanathan

A generalized action for strings which is a sum of the Nambu-Goto and the extrinsic curvature (the energy integral of the surface) terms, is used to couple strings to gravity. It is shown that the conical singularity has deficit angle that has contributions from both the above terms. It is found that the effect of extrinsic curvature is to oppose that of the

L. Martin, D. G. C. McKeon

The heat kernel $M_{xy} = <x\mid exp [ 1/\sqrt{g} \partial_μg^{μν} \sqrt{g} \partial_ν]t \mid y>$ is of central importance when studying the propagation of a scalar particle in curved space. It is quite convenient to analyze this quantity in terms of classical variables by use of the quantum mechanical path integral; regrettably it is not entirely clear how

Mariano Santander, Francisco J. Herranz

The geometries of spaces having as groups the real orthogonal groups and some of their contractions are described from a common point of view. Their central extensions and Casimirs are explicitly given. An approach to the trigonometry of their spaces is also advanced.

Y. S. Kim

Einstein&#39;s $E = mc^{2}$ unifies the momentum-energy relations for massive and massless particles. According to Wigner, the internal space-time symmetries of massive and massless particles are isomorphic to $O(3)$ and $E(2)$ respectively. According to Inonu and Wigner, $O(3)$ can be contracted to $E(2)$ in the large-radius limit. It is noted that the $O(3

Oliver Bärwald, Reinhold W. Gebert

The 727-dimensional root space associated with the level-2 root $\bLambda_1$ of the hyperbolic Kac--Moody algebra $E_{10}$ is determined using a recently developed string theoretic approach to hyperbolic algebras. The explicit form of the basis reveals a complicated structure with transversal as well as longitudinal string states present.

Massimo Giovannini

We discuss some perturbative techniques suitable for the gauge-invariant treatment of the scalar and tensor inhomogeneities of an anisotropic and homogeneous background geometry whose spatial section naturally decomposes into the direct product of two maximally symmetric Eucledian manifolds, describing a general situation of dimensional decoupling in which $

Choon-Lin Ho

We discuss $w_\infty$ and $sl_q(2)$ symmetries in multiple Chern-Simons theory on a torus. It is shown that these algebraic structures arise from the dynamics of the non-integrable phases of the Chern-Simons fields. The generators of these algebras are constructed from the Wilson line operators corresponding to these phases. The vacuum states form the basis

Choon-Lin Ho

We discuss $w_\infty$ and $sl_q(2)$ symmetries in Chern-Simons theory and Landau problem on a torus. It is shown that when the coefficient of the Chern-Simons term, or when the total flux passing through the torus is a rational number, there exist in general two $w_\infty$ and two $sl_q(2)$ algebras, instead of one set each discussed in the literature. The g

Anna Tollsten

We find the comlete solution to ten-dimensional supergravity coupled to a three-form field strength, given the ``standard ansatz&#34; for the fields, and show that in addition to the well-known elementary and solitonic (heterotic) string solutions, one of the possibilities is an (unstable) elementary type I string solution.

I. D. Lawrie, D. B. McKernan

Real-time perturbation theory is formulated for complex scalar fields away from thermal equilibrium in such a way that dissipative effects arising from the absorptive parts of loop diagrams are approximately resummed into the unperturbed propagators. Low order calculations of physical quantities then involve quasiparticle occupation numbers which evolve with

C. Fabre

This is a summary of the analysis of the one-loop effective action in Z_2-orbifold compactifications of type-I theory presented in references [1,2]. We show how, for non-abelian group factors, the threshold effects are ultraviolet finite though given entirely by a six-dimensional field theory expression. We also discuss implications for the equivalence betwe

J. Gamboa, I. Schmidt, L. Vergara

The axial anomaly and fermion condensate in the light cone Schwinger model are studied following path integral methods. This formalism allows for a simple and direct calculation for these and other vacuum dependent phenomena.

Frank Cuypers, Paul H. Frampton, Reinhold Rueckl

We study the production of scalar and vector leptoquarks in $e^-e^-$ scattering. We use the most general couplings to the known fermions which are dimensionless, baryon and lepton number conserving, and $SU(3)_c \otimes SU(2)_L \otimes U(1)_Y$ invariant. Expressions are presented for production cross sections and predictions are given for future linear colli

Kenneth Lane

The motivations for studying dynamical scenarios of electroweak and flavor symmetry breaking are reviewed and the latest ideas, especially topcolor-assisted technicolor, are summarized. Several technicolor signatures at the Tevatron and Large Hadron Collider are described and it is emphasized that all of them are well within the reach of these colliders. (Th

George Sterman

Recent developments in the theory and experiment of QCD hard scattering are described.

Andrzej J. Buras

We review the status of the flavour-changing neutral-current processes (FCNC). In particular we discuss: i) Main targets of the field, ii) The theoretical framework for FCNC, iii) Standard analysis of the unitarity triangle, iv) $\varepsilon&#39;/\varepsilon$, v) Radiative, rare and CP-violating decays, vi) CP-asymmetries in B-decays, vii) Comparision of the

Pran Nath, R. Arnowitt

A review of recent developments in the analyses of supersymmetric dark matter is given.

J. A. Grifols, R. N. Mohapatra, A. Riotto

We derive the allowed mass range for the superlight gravitino present in a large class of supersymmetric models from the observed luminosity from Supernova 1987A. We find that for photino masses of order 100 GeV, the mass range $2.6\times 10^{-6} eV \leq m_{\tilde{g}} \leq 2.2\times 10^{-8} eV$ for the gravitino $\tilde{g}$ is excluded by SN1987A observation

K. G. Chetyrkin, B. A. Kniehl, M. Steinhauser

By means of a heavy-top-quark effective Lagrangian, we calculate the three-loop corrections of O(alpha_s^2 G_F M_t^2) to the H->bb-bar partial decay width of the standard-model Higgs boson with intermediate mass M_H<<2M_t. We take advantage of a soft-Higgs theorem to construct the relevant coefficient functions. We present our result both in the MS-bar and o

G. Martinelli

Weak decays and mixing of B-hadrons play a special role in our understanding of the physics of the Standard Model and beyond. The measured amplitudes, however, result from a complicated interplay of weak and strong interaction effects. Understanding strong interaction dynamics, which becomes simpler for heavy quarks, is thus a fundamental part of the game. I

G. P. Korchemsky

I review a recent progress in understanding of QCD Pomeron and its relation to exactly solvable models.

A. V. Anisovich, V. V. Anisovich, Yu. D. Prokoshkin, A. V. Sarantsev

We summarize the results of the investigation of the $IJ^{PC}=00^{++}$ wave which is devoted to the search for the lightest scalar glueball. In the framework of the K-matrix formalism, the $q\bar q$-nonet classification of the scalar/isoscalar states is performed in the mass region below 1900 MeV basing on the following data: GAMS data for $π^-p\toπ^0π^0n$,

Arnd Brandenburg

We discuss the prospects to observe effects of transverse polarization and spin-spin correlations of top quark pairs produced at hadron colliders.

J. Bartels, V. Del Duca, M. Wusthoff

As a signal for the BFKL Pomeron in small-x deep inelastic $ep$ scattering, we calculate the azimuthal dependence of the inclusive cross section of forward jets relative to the outgoing electron. For not very large differences in rapidity between the current jet and the forward jet the cross section peaks at $π/2$. For increasing rapidity BFKL dynamics predi

R. Barbieri, L. J. Hall, S. Raby, A. Romanino

A general operator expansion is presented for quark and lepton mass matrices in unified theories based on a U(2) flavor symmetry, with breaking parameter of order $V_{cb} \approx m_s/m_b \approx \sqrt{m_c/m_t}$. While solving the supersymmetric flavor-changing problem, a general form for the Yukawa couplings follows, leading to 9 relations among the fermion

P. K. Coyle I. G. Halliday P. Suranyi

The three dimensional U(1) Lattice Gauge, in the weak coupling limit, is dual to a Discrete Gaussian model. We investigate this dual model and use it to calculate properties of the U(1) theory. We find that, because of the nature of the dual model, its advantages are outweighed by large autocorrelation times generated when the dual system becomes disordered.

Janos Polonyi

Certain effective vertices may generate a non-homogeneous, periodic vacuum structure. The excitations above such a vacuum are studied in the framework of the $ϕ^4$ and gauge models. The formation of the non-homogeneous vacuum is accompanied by the dynamical breakdown of the space-time inversion symmetry. Chiral transformation is introduced for bosons in clos

A. Z. Wang, M. F. A. da Silva, N. O. Santos

The Levi-Civita (LC) solution is matched to a cylindrical shell of an anisotropic fluid. The fluid satisfies the energy conditions when the mass parameter $σ$ is in the range $0 \le σ\le 1$. The mass per unit length of the shell is given explicitly in terms of $σ$, which has a finite maximum. The relevance of the results to the non-existence of horizons in t

A. L. Larsen, C. O. Lousto

We continue the study of the existence and stability of static spherical membrane configurations in curved spacetimes. We first consider higher order membranes described by a Lagrangian which, besides the Dirac term, includes a term proportional to the scalar curvature of the world--volume ${}^{(3)}R$. Notably, in this case, the equations of motion can be re

Richard B. Melrose, Victor Nistor

We compute $K$-theory invariants of algebras of pseudodifferential operators on manifolds with corners and prove an equivariant index theorem for operators invariant with respect to an action of $\R^k.$ We discuss the relation between our results and the $η$-invariant.

I. A. Taimanov

The detailed analysis of the generalised Weierstrass representation of surfaces of revolution and their deformations induced by the modified Korteweg--de Vries (mKdV) equations is done. In particular, it is shown that these deformations preserve tori. The geometric meaning of the potential of surface is discussed and the deformations of potentials induced by

I. A. Taimanov

Normal geodesic flows flows of Carnot-Caratheodory are discussed from the point of view of the theory of Hamiltonian systems. The geodesic flows corresponding to left-invariant metrics and left- and -right-invariant rank 2 distributions on the three-dimensional Heisenberg group are analysed as integrable systems. The flows corresponding to left-invariant met

Alessandro Vespignani, Stefano Zapperi, Vittorio Loreto

We introduce the general formulation of a renormalization method suitable to study the critical properties of non-equilibrium systems with steady-states: the Dynamically Driven Renormalization Group. We renormalize the time evolution operator by computing the rescaled time transition rate between coarse grained states. The obtained renormalization equations

Elisa Ercolessi, Pierbiagio Pieri, Marco Roncaglia

We study the so-called nonmagnetic phases (dimer and flux states) in the t-J model below half filling. We present a new phase diagram, at zero and finite temperature, that includes broad areas of phase coexistence (dimer-flux or flux-uniform), in accordance with experimental and numerical data on the possibility of separation into hole-rich and hole-poor reg

T. Lorenz, U. Ammerahl, T. Auweiler, B. Büchner

We present high resolution measurements of the thermal expansion coefficient and the magnetostriction along the a-axis of CuGeO_3 in magnetic fields up to 16 Tesla. From the pronounced anomalies of the lattice constant a occurring for both temperature and field induced phase transitions clear structural differences between the uniform, dimerized, and incomme

J. Sánchez-Cañizares, F. Sols

We present a scattering description of transport in several normal-superconductor structures. We show that the related requirements of self-consistency and current conservation introduce qualitative changes in the transport behavior when the current in the superconductor is not negligible. The energy thresholds for quasiparticle propagation in the supercondu

Steven Abney

Probabilistic analogues of regular and context-free grammars are well-known in computational linguistics, and currently the subject of intensive research. To date, however, no satisfactory probabilistic analogue of attribute-value grammars has been proposed: previous attempts have failed to define a correct parameter-estimation algorithm. In the present pape

M. Ostrowski

A mechanism of ultra-high energy (UHE) cosmic ray acceleration in extragalactic radio sources at the interface between the relativistic jet and the ambient medium is discussed as a supplement to the shock acceleration in `hot spots&#39;. Particles accelerated at the jet side boundary are expected to dominate at highest energies. The spectrum formation near t

M. Ostrowski

Theory of the first-order Fermi acceleration of cosmic ray particles at relativistic shock waves is reviewed. We consider shocks with parallel and oblique, sub- and super-luminal magnetic field configurations and with finite-amplitude magnetic field perturbations. A role of oblique field configurations and field perturbations in forming the cosmic ray energy

Julio F. Navarro, Vincent R. Eke, Carlos S. Frenk

We use N-body simulations to examine the effects of mass outflows on the density profiles of cold dark matter (CDM) halos surrounding dwarf galaxies. In particular, we investigate the consequences of supernova-driven winds that expel a large fraction of the baryonic component from a dwarf galaxy disk after a vigorous episode of star formation. We show that t

Bram Boroson, Richard McCray, Christina Oelfke Clark, Jonathan Slavin

With the High Resolution Spectrograph aboard the Hubble Space Telescope we obtained high signal-to-noise (S/N > 200 - 600 per 17 km/s resolution element) spectra of narrow absorption lines toward the Wolf-Rayet star HD 50896. The ring nebula S308 that surrounds this star is thought to be caused by a pressure-driven bubble bounded by circumstellar gas (most l

Naoki Seto, Jun&#39;ichi Yokoyama, Takahiko Matsubara, Masaru Siino

Evolution of genus density is calculated from Gaussian initial conditions using Zel&#39;dovich approximation. A new approach is introduced which formulates the desired quantity in a rotationally invariant manner. It is shown that normalized genus density does not depend on the initial spectral shape but is a function of the fluctuation amplitude only.

Daniela Calzetti

The reddening properties and the star formation history of a sample of 19 starburst galaxies are investigated using multiwavelength spectroscopy and infrared broad band photometry. The difference in reddening between the ionized gas and the stars is explained as difference in the covering factors of the dust in front of the gas and of the stars. A ``template

E. M. Berkhuijsen, C. Horellou, M. Krause, N. Neininger

We discuss the regular magnetic field in the galaxy M51 on the basis of a new interpretation of polarization angles observed at the wavelengths 2.8, 6.2, 18.0 and 20.5 cm. We found a magneto-ionic halo in M51 with a radial extent of about 10 kpc. The regular magnetic fields in the disk and the halo have different structures. The regular magnetic field in the

A. Burkert, G. Smith

The kinematical and spatial properties of the metal-rich globular clusters in the Galaxy ([Fe/H] > -0.8) indicates that these objects do not comprise a homogeneous population. Three subsystems are identified. The highest-mass clusters exhibit a very slow net rotation with a speed of v_rot = 24 km/s and v_rot/sigma = 0.3, indicative of a centrally condensed,

Matteo Guainazzi, Tatehiro Mihara, Chiko Otani, Masaru Matsuoka

We present the results of an extensive analysis of the ``ASCA&#39;&#39; AO2 observation of the Seyfert 1 galaxy NGC4051. The target exhibits broadband [0.5--10 keV] variability by a factor $\sim 8$ on time scales $\sim 10^4 s$, with a typical doubling time $\sim 500 s$. The spectrum is characterized by a strong emission excess over the extrapolated power law

P. A. Woudt, A. P. Fairall, R. C. Kraan-Korteweg

The nature and the extent of the Great Attractor has been the subject of much debate, not in the least due to the unfortunate position of its central part being behind the Milky Way. We here present the latest results from our deep optical galaxy search in the southern Milky Way. A full view of the southern hemisphere is emerging, revealing ACO 3627 as the m

J. Sommer-Larsen, T. C. Beers, C. Flynn, R. Wilhelm

We re-analyse the kinematics of the system of blue horizontal branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of radial and tangential velocity dispersions in the halo as a function of galactocentric distance r proposed by Sommer-Larsen, Flynn & Christensen (1994), using a much larger sampl

Peter Arnold, Yan Zhang

A companion article analyzed very weakly first-order phase transitions in the cubic anisotropy model using $\eps$ expansion techniques. We extend that analysis to a calculation of the relative discontinuity of specific heat across the transition.

Peter Arnold, Laurence G. Yaffe

The cubic anisotropy model provides a simple example of a system with an arbitrarily weak first-order phase transition. We present an analysis of this model using $\eps$-expansion techniques with results up to next-to-next-to-leading order in $\eps$. Specifically, we compute the relative discontinuity of various physical quantities across the transition in t

Gary T. Horowitz, Donald Marolf

It is shown that many modes of the gravitational field exist only inside the horizon of an extreme black hole in string theory. At least in certain cases, the number of such modes is sufficient to account for the Bekenstein-Hawking entropy. These modes are associated with sources which carry Ramond-Ramond charge, and so may be viewed as the strong coupling l

C. G. Callan, S. S. Gubser, I. R. Klebanov, A. A. Tseytlin

We calculate the emission and absorption rates of fixed scalars by the near-extremal five-dimensional black holes that have recently been modeled using intersecting D-branes. We find agreement between the semi-classical and D-brane computations. At low energies the fixed scalar absorption cross-section is smaller than for ordinary scalars and depends on othe

Wei-Dong Ruan

In this paper we will discuss local coordinates canonically corresponding to a Kahler metric. We will also discuss and prove the $C^\infty$ convergence of Bergman metrics following Tian&#39;s result on $C^2$ convergence of Bergman metrics. At the end, we present an interesting characterization of ample line bundle that could be useful in arithmetic geometry.

M. Franz, C. Kallin, A. J. Berlinsky, M. I. Salkola

We argue that the standard Abrikosov-Gorkov (AG) type theory of $T_c$ in disordered $d$-wave superconductors breaks down in short coherence length high-$T_c$ cuprates. Numerical calculations within the Bogoliubov-de Gennes formalism demonstrate that the correct description of such systems must allow for the spatial variation of the order parameter, which is

Thomas Chen, William D. Walker, Jurg Dual

We solve the linearized Einstein equations for a specific oscillating mass distribution and discuss the usual counterarguments against the existence of observable gravitational retardations in the &#34;near zone&#34;, where d/r << 1 (d = oscillation amplitude of the source, r = distance from the source). We show that they do not apply in the region d/r \appr

R. Poppe, S. Schwager

We construct 4-dimensional cosmological FRW--models by compactifying a black 5-brane solution of type IIB supergravity, which carries both magnetic NS-NS-charge and RR-charge. The influence of nontrivial RR-fields on the dynamics of the cosmological models is investigated.

Michael I. Eides, Howard Grotch, Valery A. Shelyuto

The analytic result for the radiative correction of order $α^{2}(Zα)^{5}m$ to the Lamb shift connected with a polarization insertion in one of the two external Coulomb lines is obtained. This correction arises from a gauge invariant set of diagrams which contain, besides the polarization insertion in the Coulomb leg, all one-loop radiative photon insertions

Paolo Muratore Ginanneschi

By means of Ito calculus it is possible to find, in a straight-forward way, the analytical solution to some equations related to the passive tracer transport problem in a velocity field that obeys the multidimensional Burgers equation and to a simple model of reactive tracer motion.

H. Dilger

The perfect action of free staggered fermions is calculated by blocking from the continuum for degenerate and non-degenerate flavor masses. The symmetry structure, connecting flavor transformations and translations, is explained directly from the blocking scheme. It is convenient to use a modified Fourier transformation, respecting this connection, to treat

G. Calucci, R. Ragazzon, D. Treleani

High energy hadronic interactions can produce a final state characterized by minijets separated by a large gap in the rapidity distribution of the produced secondary particles. We discuss the process by keeping into account the possibility of having multiple parton collisions in the hadronic interaction. At Tevatron energy the correction to the single scatte

Zurab Tavartkiladze

A solution of the doublet-triplet splitting problem in the supersymmetric $SU(6)$ gauge theory is suggested. The `missing doublet&#39; multiplet -- 175-plet of the $SU(6)$ group as well as the custodial $SU(2)_{cus}$ global symmetry play crucial role for achieving the doublet-triplet hierarchy. Two examples in which the doublet-triplet splitting occurs natur

M. R. Rahimi Tabar, A. Aghamohammadi, M. Khorrami

We study the correlation functions of logarithmic conformal field theories. First, assuming conformal invariance, we explicitly calculate two-- and three-- point functions. This calculation is done for the general case of more than one logarithmic field in a block, and more than one set of logarithmic fields. Then we show that one can regard the logarithmic

V. Pislar, F. Durret, D. Gerbal, G. B. Lima Neto

We present an X-ray analysis of the rich cluster ABCG 85 based on ROSAT PSPC data. By applying an improved wavelet analysis, we show that our view of this cluster is notably changed from what was previously believed (a main region and a south blob). The main emission comes from the central part of the main body of the cluster on which is superimposed that of

Daniel Arnaudon

The structure of irreducible representations of (restricted) U_q(sl(3)) at roots of unity is understood within the Gelfand--Zetlin basis. The latter needs a weakened definition for non integrable representations, where the quadratic Casimir operator of the quantum subalgebra U_q(sl(2)) of U_q(sl(3)) is not completely diagonalized. This is necessary in order

Nils A. Tornqvist

A new mechanism for spontaneous breaking of flavour symmetry is demonstrated. An exactly flavour symmetric model with degenerate bare nonets and with sufficiently strong tri-linear meson couplings is shown to lead to self-consistency equations which are unstable. Instead there exists a stable solution, which break flavour symmetry spontaneously in the mass s

Soo-Jong Rey

We study classical and quantum aspects of D=4, N=2 BPS black holes for T_2 compactification of D=6, N=1 heterotic string vacua. We extend dynamical relaxation phenomena of moduli fields to background consisting of a BPS soliton or a black hole and provide a simpler but more general derivation of the Ferrara-Kallosh&#39;s extremized black hole mass and entrop

Yaw-Hwang Chen, Su-Long Nyeo, Chung-Yi Wu

We calculate the single-spin and double-spin asymmetry differential cross sections for the polarized hadron scattering $PP \to l^+ l^- + jet$ up to $O(α_s)$ by the helicity amplitude method. Numerical results of the differential cross sections, which can be used to probe the spin contents of the proton, are obtained with several sets of polarized parton dist

G. E. Volovik

Poisson brackets for the Hamiltonian dynamics of vortices are discussed for 3 regimes, in which the dissipation can be neglected and the vortex dynamics is reversible: (i) The superclean regime when the spectral flow is suppressed. (ii) The regime when the fermions are pinned by crystal lattice. This includes also the regime of the extreme spectral flow of f

M. Hanasz, H. Lesch

In this paper we investigate the idea of Hanasz & Lesch 1993 that the galactic dynamo effect is due to the Parker instability of magnetic flux tubes. In addition to the former approach, we take into account more general physical conditions in this paper, by incorporating cosmic rays and differential forces due to the axisymmetric differential rotation and th

Kazuo Fujikawa, Harunobu Kubo, C. H. Oh

An extra term generally appears in the q-deformed $su(2)$ algebra for the deformation parameter $q = \exp{ 2 πiθ}$, if one combines the Biedenharn-Macfarlane construction of q-deformed $su(2)$, which is a generalization of Schwinger&#39;s construction of conventional $su(2)$, with the representation of the q-deformed oscillator algebra which is manifestly fr

E. S. Soldatov, V. V. Khanin, A. S. Trifonov, S. P. Gubin

A room temperature single-electron transistor based on the single cluster molecule has been demonstrated for the first time. Scanning tunneling microscope tip was used to study the transport via single carboran cluster molecule 1,7-(CH_3)_2-1,2-C_2B_{10}H_9Tl(OCOCF_3)_2 incorporated into the Langmuir-Blodgett monolayer of the stearic acid. DC I-V curves at 3

Jan de Gier, Bernard Nienhuis

We present a detailed calculation of the recently published exact solution of a random tiling model possessing an eight-fold symmetric phase. The solution is obtained using Bethe Ansatz and provides closed expressions for the entropy and phason elastic constants. Qualitatively, this model has the same features as the square-triangle random tiling model. We u

Huw Price

Physics takes for granted that interacting physical systems with no common history are independent, before their interaction. This principle is time-asymmetric, for no such restriction applies to systems with no common future, after an interaction. The time-asymmetry is normally attributed to boundary conditions. I argue that there are two distinct independe

Walter T. Strunz

We demonstrate the relevance of complex Gaussian stochastic processes to the stochastic state vector description of non-Markovian open quantum systems. These processes express the general Feynman-Vernon path integral propagator for open quantum systems as the classical ensemble average over stochastic pure state propagators in a natural way. They are the col

Alexander Groisman, Victor Steinberg

We report experimental observation of a localized structure, which is of a new type for dissipative systems. It appears as a solitary vortex couple (&#34;diwhirl&#34;) in Couette flow with highly elastic polymer solutions. A unique property of the diwhirls is that they are stationary, in contrast to the usual localized wave structures in both Hamiltonian and

T. Waas, M. Rho, W. Weise

We evaluate the effective kaon mass in dense nuclear matter. Pauli blocking and nucleon-nucleon short-range correlations are incorporated. The effects of short-range correlations are shown to be moderate and figure importantly only at densities larger than 2 times normal nuclear density. We discuss the relations between the present results and the results ob

R. Emparan

The properties of composite black holes in the background of electric or magnetic flux tubes are analyzed, both when the black holes remain in static equilibrium and when they accelerate under a net external force. To this effect, we present a number of exact solutions (generalizing the Melvin, C and Ernst solutions) describing these configurations in a theo

M. Khorrami, A. Aghamohammadi

We present the technique of derivation of a theory to obtain an $(n+1)f$-degrees-of-freedom theory from an $f$-degrees-of-freedom theory and show that one can calculate all of the quantities of the derived theory from those of the original one. Specifically, we show that one can use this technique to construct, from an integrable system, other integrable sys

J. Rasmussen

In this thesis steps are taken in the direction of formulating non-critical strings in the framework of the $G/G$ approach. A major part of the thesis is concerned with conformal field theory based on affine $SL(2)$ current algebra, in particular for admissible representations which are relevant in the $SL(2)/SL(2)$ description of coupling conformal minimal

Yaw-Hwang Chen, Ron-Jou Hsieh, Chilong Lin

A split dimensional regularization, which was introduced for the Coulomb gauge by Leibbrandt and Williams, is used to regularize the spurious singularities of Yang-Mills theory in the temporal gauge. Typical one-loop split dimensionally regularized temporal gauge integrals, and hence the renormalization structure of the theory are shown to be the same as tho

Jose Daniel Edelstein

We study the cosmological constant problem in a three-dimensional N=2 supergravity theory with gauge group SU[2]_{global}xU[1]_{local}. The model we consider is known to admit string-like configurations, the so-called semi-local cosmic strings. We show that the stability of these solutions is provided by supersymmetry through the existence of a lower bound f

B. Balaji

Conventional technicolor models with light charged technipions ($π^{\pm} _T$) lead to an unacceptably large contribution to $t\ra {π^+_T} b$ decay rate. Topcolor-assisted technicolor models also have additional PGBs called top-pions ($π^{\pm}_t$) which may contribute to this decay. We study the potentially dangerous mixing of charged top-pion and technipions

Paul Geiger, Nathan Isgur

Nontrivial $q \bar q$ sea effects have their origin in the low-$Q^2$ dynamics of strong QCD. We present here a quark model calculation of the contribution of $s \bar s$ pairs arising from a {\it complete} set of OZI-allowed strong $Y^*K^*$ hadronic loops to the net spin of the proton, to its charge radius, and to its magnetic moment. The calculation is perfo

Bing An Li

A general expression of the axial-vector current is presented, in which both the effects of the chiral symmetry breaking and the spontaneous chiral symmetry breaking are included. A new resonance formula of the axial-vector meson is derived and in the limit of $q^{2}\rightarrow 0$ this formula doesn&#39;t go back to the ``chiral limit``. The studies show tha