May 1999 arXiv papers — page 12

Jonathan Bagger, Yi-Yen Wu

We study supersymmetry breaking by hidden-sector gaugino condensation in N=1 D=4 supergravity models with multiple dilaton-like moduli fields. Our work is motivated by Type I string theory, in which the low-energy effective Lagrangian can have different dilaton-like fields coupling to different sectors of the theory. We construct the effective Lagrangian for

S. G. Rajeev

We develop a theory of non-relativistic bosons in two spatial dimensions with a weak short range attractive interaction. In the limit as the range of the interaction becomes small, there is an ultra-violet divergence in the problem. We devise a scheme to remove this divergence and produce a completely finite formulation of the theory. This involves reformula

J. M. Camino, A. V. Ramallo, J. M. Sanchez de Santos

We study the embedding of D(8-p)-branes in the background geometry of parallel Dp-branes for $p\le 6$. The D(8-p)-brane is extended along the directions orthogonal to the Dp-branes of the background. The D(8-p)-brane configuration is determined by its Dirac-Born-Infeld plus Wess-Zumino-Witten action. We find a BPS condition which solves the equation of motio

Piet Claus, Murat Gunaydin, Renata Kallosh, J. Rahmfeld

The GS superstring on AdS_5 x S^5 has a nonlinearly realized, spontaneously broken SU(2,2|4) symmetry. Here we introduce a two-dimensional model in which the unbroken SU(2,2|4) symmetry is linearly realized. The basic variables are supertwistors, which transform in the fundamental representation of this supergroup. The quantization of this supertwistor model

Graciela Gelmini, Paolo Gondolo, Gabriele Varieschi

We compute the next-to-leading order QCD predictions for the vertical flux of atmospheric muons and neutrinos from decays of charmed particles, for different PDF's (MRS-R1, MRS-R2, CTEQ-4M and MRST) and different extrapolations of these at small partonic momentum fraction x. We find that the predicted fluxes vary up to almost two orders of magnitude at t

I. V. Musatov, A. V. Radyushkin

We discuss the structure of the ``forward visible'' (FW) parts of double and skewed distributions related to usual distributions through reduction relations. We use factorized models for double distributions (DDs) f(x, alpha) in which one factor coincides with the usual (forward) parton distribution and another specifies the profile characterizing th

S. Groote

This talk presents work concepts and results for the determination of the fine structure constant $α$ at the $Z_0$ mass resonance. The problem consisting of the break-down of global duality for singular integral weights is circumvented by using a polynomial fit which mimics this weight function. This method is conservative in the sense that it is mostly inde

M. Vanderhaeghen, P. A. M. Guichon, M. Guidal

We estimate the leading order amplitudes for exclusive photon and meson electroproduction reactions at large Q^2 in the valence region in terms of skewed quark distributions. As experimental investigations can currently only be envisaged at moderate values of Q^2, we estimate power corrections due to the intrinsic transverse momentum of the partons in the me

M. W. Krasny

I summarise the experimental results presented during the hadronic session of the XXXIVth Rencontre de Moriond.

Chris Quigg

These three lectures review the state of our understanding of electroweak interactions and the search for the agent of electroweak symmetry breaking. The themes of the lectures are (i) the electroweak theory and its experimental status, (ii) the standard-model Higgs boson, and (iii) aspects of electroweak theory beyond the standard SU(2)_L x U(1)_Y model.

M. K. Volkov, V. L. Yudichev

First radial excitations of the scalar meson nonet and pseudoscalar mesons η, η' are described in a nonlocal chiral quark model of the Nambu--Jona-Lasinio type with 't Hooft interaction. In this model simple form factors are used, which allows us to describe first radial excitations of the mesons and to conserve the gap equations describing spontaneo

B. Buschbeck, F. Mandl

Multiplicity fluctuations in rings around the jet axis and in off-axis cones have been measured by the DELPHI collaboration in $e^+e^-$ annihilations into hadrons at LEP energies. The measurements are compared with analytical perturbative QCD calculations for the corresponding multiparton system, using the concept of Local Parton Hadron Duality. Some qualita

Jonathan L. Rosner

Observed decay rates indicate large phase differences among the amplitudes for the charge states in $D \to \bar K π$ and $D \to \bar K^* π$ but relatively real amplitudes in the charge states for $D \to \bar K ρ$. This feature is traced using an SU(3) flavor analysis to a sign flip in the contribution of one of the amplitudes contributing to the latter proce

Uma Mahanta

In this work we study the effect of R parity breaking couplings on the process e^-e^-->{\tilde e}_L{\tilde e}_R. We find that an e^-e^- linear collider opearting at a center of mass energy of 500 Gev with a luminosity of 50 fb^{-1} will be able to probe the coupling [λ_{211}+λ_{311}]^{1/2} down to .045 for a bino mass of 100 Gev and selectron mass of 200 Gev

J. Matias

We present the contributions of new CP phases in CP asymmetries of two-body neutral $B_s$ decays coming from a left--right model with spontaneous CP violation. Large deviations from the Standard Model predictions can be accommodated in a natural way by this type of models. The new physics effects on the mixing, width difference and decays are analysed. In pa

Kunio Takamatsu

The amplitude analysis has been performed on the pi0 pi0 final state obtained in the pi- p charge exchange process. The pi0 pi0 scattering amplitudes have been obtained for the S and D waves by the Chew-Low extrapolation and the partial wave analysis. Breit Wigner parameters have been obtained for f0(1370) and f2(1270). I=0 S wave pi0 pi0 scattering phase sh

Tilo Wettig

Chiral random matrix theory makes very detailed predictions for the spectral correlations of the QCD Dirac operator, both in the bulk of the spectrum and near zero virtuality. These predictions have been successfully tested in lattice QCD simulations by several groups. Moreover, the domain of validity of random matrix theory has been predicted theoretically

Fabrizio Palumbo

We investigate QCD at finite temperature in the quark composites approach, which is based on the use of quark composites with hadronic quantum numbers as fundamental variables. We find that chiral symmetry restoration and quark deconfinement are one and the same first order phase transition, whose critical temperature, in a one loop approximation, is $T= 2\s

P. Vannerem, K. -R. Mueller, B. Schoelkopf, A. Smola

We have studied the application of different classification algorithms in the analysis of simulated high energy physics data. Whereas Neural Network algorithms have become a standard tool for data analysis, the performance of other classifiers such as Support Vector Machines has not yet been tested in this environment. We chose two different problems to comp

F. Ronga

We present updated results of the measurement of upward-going muons produced by neutrino interactions in the rock below the MACRO detector. These data support MACRO's previously published results. They favor a neutrino oscillation explanation of the atmospheric neutrino anomaly.

Masaru Shibata

We have carried out simulations of the coalescence between two relativistic clusters of collisionless particles using a 3D numerical relativity code. We have adopted a new spatial gauge condition obtained by slightly modifying the minimum distortion gauge condition proposed by Smarr and York and resulting in a simpler equation for the shift vector. Using thi

J. M. M. Senovilla

Inspired by classical work of Bel and Robinson, a natural purely algebraic construction of super-energy tensors for arbitrary fields is presented, having good mathematical and physical properties. Remarkably, there appear quantities with mathematical characteristics of energy densities satisfying the dominant property, which provides super-energy estimates u

K. Kleidis, H. Varvoglis, D. B. Papadopoulos

We study the resonant interaction of charged particles with a gravitational wave propagating in the non-empty interstellar space in the presence of a uniform magnetic field. It is found that this interaction can be cast in the form of a parametric resonance problem which, besides the main resonance, allows for the existence of many secondary ones. Each of th

M. Rainer

The geometric operators of area, volume, and length, depend on a fundamental length l of quantum geometry which is a priori arbitrary rather than equal to the Planck length l_P. The fundamental length l and the Immirzi parameter $γ$ determine each other. With any l the entropy formula is rendered most naturally in units of the length gap sqrt{{sqrt 3}/2} (sq

Stephane Pairault, David Senechal, A. -M. S. Tremblay

The strong-coupling perturbation theory of the Hubbard model is presented and carried out to order (t/U)^5 for the one-particle Green function in arbitrary dimension. The spectral weight A(k,omega) is expressed as a Jacobi continued fraction and compared with new Monte-Carlo data of the one-dimensional, half-filled Hubbard model. Different regimes (insulator

M. Leadbeater, R. Raimondi, P. Schwab, C. Castellani

We report on a novel non-linear electric field effect in the conductivity of disordered conductors. We find that an electric field gives rise to dephasing in the particle-hole channel, which depresses the interference effects due to disorder and interaction and leads to a non-linear conductivity. This non-linear effect introduces a field dependent temperatur

W. Li, X. Cai

A new quantity, average fitness, is introduced in Bak-Sneppen evolution model. Through this new quantity, a new hierarchy of avalanches is observed in the evolution of Bak-Sneppen model. An exact gap equation, governing the self-organization of the model, is presented. It is found that the self-organized threshold of the new quantity can be exactly obtained.

Erwin Frey, David R. Nelson, Leo Radzihovsky

We demonstrate that particles confined to two dimensions (2d) and subjected to a one-dimensional (1d) periodic potential exhibit a rich phase diagram, with both ``locked floating solids'' and smectic phases. The resulting phases and phase transitions are studied as a function of temperature and potential strength. We find reentrant melting as a funct

J. A. Verges

Kubo formula is used to get the d.c conductance of a statistical ensemble of two-dimensional clusters of the square lattice in the presence of standard diagonal disorder, a uniform magnetic field and random magnetic fluxes. Working within a one-band tight-binding approach the calculation is quite general. The shape of the cluster is rectangular with ideal le

E. V. Bezuglyi, E. N. Bratus', V. S. Shumeiko, G. Wendin

We study the dc conductance and current fluctuations in diffusive voltage biased SNS junctions with a tunnel barrier inside the mesoscopic normal region. We find that at subgap voltages, eV<2Delta/n, the current associated with the chain of n Andreev reflections is mapped onto the quasiparticle flow through a structure of n+1 voltage biased barriers connecte

D. L. Shepelyansky

The model of two electrons with Coulomb interaction on a two-dimensional (2D) disordered lattice is considered. It is shown that the interaction can give a sharp transition to delocalized states in a way similar to the Anderson transition in 3D. The localized phase appears when the ratio of the Coulomb energy to the Fermi energy becomes larger than some crit

Guido Burkard, Daniel Loss, David P. DiVincenzo, John A. Smolin

Quantum error correcting codes have been developed to protect a quantum computer from decoherence due to a noisy environment. In this paper, we present two methods for optimizing the physical implementation of such error correction schemes. First, we discuss an optimal quantum circuit implementation of the smallest error-correcting code (the three bit code).

T. Nishino, N. Shibata

Two targeting schemes have been known for the density matrix renormalization group (DMRG) applied to non-Hermitian problems; one uses an asymmetric density matrix and the other uses symmetric density matrix. We compare the numerical efficiency of these two targeting schemes when they are used for the finite temperature DMRG.

Giovanni Gallavotti

The ergodic hypothesis outgrew from the ancient conception of motion as periodic or quasi periodic. It did cause a revision of our views of motion, particularly through Boltzmann and Poincaré: we discuss how Boltmann&#39;s conception of motion is still very modern and how it can provide ideas and methods to study the problem of nonequilibrium in mechanics an

Y. Terashima, H. Kunieda, K. Misaki

We present the results of an ASCA observation of the low-luminosity Seyfert 1.5 galaxy NGC 5033. A point-like X-ray source with a luminosity of 2.3x10^{41} erg s^{-1} in the 2--10 keV band (at 18.7 Mpc; Tully 1988, AAA045.002.054) was detected at the nucleus. The X-ray light curve shows variability on a timescale of ~10^4 s with an amplitude of ~20%. The X-r

Vladimir Korchagin, Christian Theis

Using 2D nonlinear simulations, we study the generation and nonlinear evolution of spiral structure in a star-forming multi-component gravitating disk. We confirm in agreement with previous studies the destabilizing role of a cold gaseous component and extend this conclusion for multi-component star-forming disks exchanging mass and momentum between its comp

Y. Terashima

We review ASCA results on a search for low luminosity active nuclei at the center of nearby normal galaxies. More than a dozen low-luminosity AGN have been discovered with 2-10 keV luminosity in the range 10^{40-41} ergs/s. Their X-ray properties are in some respects similar to those of luminous Seyfert galaxies, but differ in other respects. We also present

C. J. Hailey, F. A. Harrison, K. Mori

Numerous reports have been made of features, either in emission or absorption, in the 10 - 1000 keV spectra of some gamma-ray bursts. Originally interpreted in the context of Galactic neutron star models as cyclotron line emission and $e^+ - e^-$ annihilation features, the recent demonstration that the majority of GRBs lie at cosmological distances make thes

Insu Yi, Stephen P. Boughn

It has been suggested that advection-dominated accretion flows (ADAFs) are responsible for the X-ray activity in nearby galactic nuclei. These X-ray bright galactic nuclei (XBGN) are a heterogeneous group which includes LINERs, low to moderate luminosity Seyferts, and narrow-line X-ray galaxies with 2-10 keV X-ray luminosities in the range ~10**39 to ~10**43

Insu Yi

We review basic properties of advection-dominated accretion flows (ADAFs) and their applications to astrophysical systems ranging from Galactic binary systems to galactic nuclei. A new classification scheme for low-luminosity, X-ray bright galactic nuclei is highlighted. Some outstanding unresolved issues are discussed.

Insu Yi, Ethan T. Vishniac

The accretion-powered, X-ray pulsar 4U 1626-67 has recently shown an abrupt torque reversal accompanied by a dramatic spectral transition and a relatively small luminosity change. The time-averaged X-ray spectrum during spin-down is considerably harder than during spin-up. The observed torque reversal can be explained by an accretion flow transition triggere

Yunyoung Choi, Jongmann Yang, Insu Yi

We apply the observed optical/X-ray spectral states of the Galactic black hole candidates (GBHCs) to the cosmological QSO luminosity evolution under the assumptions that QSOs and GBHCs are powered by similar accretion processes and that their emission mechanisms are also similar. The QSO luminosity function (LF) evolution in various energy bands is strongly

Jongmann Yang, Insu Yi

The existence of hot, two-temperature accretion flows is essential to the recent discussions of the low luminosity, hard X-ray emission from accreting neutron stars and black holes in Galactic binaries and massive black holes in low luminosity galactic nuclei. In these flows, protons are essentially virialized and relativistic energies for non-thermal proton

S. G. Ryan, T. C. Beers, K. A. Olive, B. D. Fields

In the standard hot big bang nucleosynthesis (BBN) model the primordial abundances of H, H2, He3, He4, and Li7, fix the baryon density of the universe, $Ω_b$, via the baryon-to-photon ratio, $η$, for a given Hubble parameter. Recent observations of Li show that its intrinsic dispersion in metal-poor stars is essentially zero, and the random error in the mean

G. Chabrier, I. Baraffe, F. Allard, P. H. Hauschildt

We briefly summarize our present knowledge of the theory of low-mass stars and substellar objects and their contribution to the Galactic population.

Jelle S. Kaastra, Richard Lieu, Jonathan P. D. Mittaz, Johan A. M. Bleeker

We report the detection of both soft and hard excess X-ray emission in the cluster of galaxies A 2199, based upon spatially resolved spectroscopy with data from the BeppoSAX, EUVE and ROSAT missions. The excess emission is visible at radii larger than 300 kpc and increases in strength relative to the isothermal component. The total 0.1-100 keV luminosity of

M. Victoria Alonso, Carlos Valotto, Diego G. Lambas, Hernan Muriel

We present 83 new galaxy radial velocities in the field of 18 APM clusters with redshifts between 0.06 and 0.13. The clusters have Abell identifications and the galaxies were selected within 0.75 h$^{-1}$Mpc in projection from their centers. We derive new cluster velocity dispersions for 13 clusters using our data and published radial velocities. We analyze

A. F. Boden, B. F. Lane

We report on the determination of the visual orbit of the double-lined spectroscopic binary system 64 Piscum with data obtained by the Palomar Testbed Interferometer in 1997 and 1998. 64 Psc is a nearly equal-mass double-lined binary system whose spectroscopic orbit is well known. We have estimated the visual orbit of 64 Psc from our interferometric visibili

Jose-Luis Gomez, Alan P. Marscher, Antonio Alberdi

We present three-epoch polarimetric images of the quasar 3C 454.3 obtained with the Very Long Baseline Array at 22 and 43 GHz. 22 GHz polarized intensity images show a sudden change in the polarization structure of a bright eastern component (which we call the ``core,&#39;&#39; although it may be neither at the upstream end of the jet nor completely stationa

P. D. Dobbie, M. A. Barstow, M. R. Burleigh, I. Hubeny

We present the results from a multi-wavelength study of the mixed H+He composition DAO white dwarf RE J0720-318. A detailed analysis of UV and EUV spectroscopic data with state-of-the-art non-LTE photospheric models demonstrates that the observed opacity to EUV radiation probably results from a more complex structure than a simple H+He, chemically layered at

A. M. Atoyan

The origin of relativistic electrons in the Crab nebula which are producing the broad-band flat radio spectrum of this prototype plerion has proved difficult to understand. Here I show that these electrons can be naturally explained as a relic population of the pulsar wind electrons that have lost most of their energy in the expanding nebula because of inten

E. Mediavilla, M. Serra-Ricart, A. Oscoz, L. J. Goicoechea

We present new long-slit William Herschel Telescope spectroscopic observations of the lens galaxy G1 associated with the double-imaged QSO 0957+561A,B. The obtained central stellar velocity dispersion, sigma_l = 310 +/- 20 km/s, is in reasonable agreement with other measurements of this dynamical parameter. Using all updated measurements of the stellar veloc

X. -Y. Xia, S. Mao, H. Wu

We present an optical spectrum for Mrk 273x, the X-ray source 1.3&#39; to the northeast of Mrk 273. The new spectrum indicates that the object is at a much higher redshift (0.458) than the value (0.0376) previously reported. All the detected emission lines show properties of Seyfert 2 galaxies. Mrk 273x has one of the highest X-ray and radio luminosities L_x

A. Vikhlinin, W. Forman, C. Jones

We present a systematic study of the hot gas distribution in the outer regions of regular clusters using ROSAT PSPC data. Outside the cooling flow region, the beta-model describes the observed surface brightness closely, but not precisely. Between 0.3 and 1 virial radii, the profiles are characterized by a power law with slope, expressed in terms of the beta

Paolo Tozzi, Piero Madau, Avery Meiksin, Martin J. Rees

We show how the investigation of the redshifted 21-cm radiation can give insight into the development of structures in the early universe (at redshifts z>5). In particular we investigate: the epoch of the first light; the fluctuations in the redshifted 21-cm emission induced by the density inhomogeneities in CDM dominated universes; the emission and absorpti

A. Kempf

It has been shown that space-time coordinates can exhibit only very few types of short-distance structures, if described by linear operators: they can be continuous, discrete or &#34;unsharp&#34; in one of two ways. In the literature, various quantum gravity models of space-time at short distances point towards one of these two types of unsharpness. Here, we

A. Shelankov, M. Ozana

The purpose of the paper is to suggest a new method which allows one to study multiple coherent reflection/transmissions by partially transparent interfaces (e.g. in multi-layer mesoscopic structures or grain boundaries in high-Tc&#39;s) in the framework of the quasiclassical theory of superconductivity. It is argued that typically the trajectory of the part

X. -D. Li, I. Bombaci, Mira Dey, Jishnu Dey

One of the most important questions in the study of compact objects is the nature of pulsars, including whether they are composed of $β$-stable nuclear matter or strange quark matter. Observations of the newly discovered millisecond X-ray pulsar \sax with the Rossi X-Ray Timing Explorer place firm constraint on the radius of the compact star. Comparing the m

David Damanik, Daniel Lenz

In this paper we introduce a method that allows one to prove uniform local results for one-dimensional discrete Schrödinger operators with Sturmian potentials. We apply this method to the transfer matrices in order to study the Lyapunov exponent and the growth rate of eigenfunctions. This gives uniform vanishing of the Lyapunov exponent on the spectrum for a

B. Feigin, S. Loktev

Here we propose a way to construct generalized Kostka polynomials. Namely, we construct an equivariant filtration on tensor products of irreducible representations. Further, we discuss properties of the filtration and the adjoint graded space. Finally, we apply the construction to computation of coinvariants of current algebras.

Teodor Banica

We give a survey of some recent results on the fusion semirings of compact quantum groups (computations of and applications to discrete quantum groups) by using the following simplifying terminology: we say that a compact quantum group G is an R^+-deformation of a compact quantum group H if their fusion semirings are isomorphic. The paper contains also some

Burt A. Ovrut

In the first lecture, we derive the five-dimensional effective action of strongly coupled heterotic string theory for the complete (1,1) sector of the theory by performing a reduction, on a Calabi-Yau three-fold, of M-theory on S1/Z2. The supersymmetric ground state of the theory is a multi-charged BPS three-brane domain wall, which we construct in general.

Massimo Giovannini

Topologically non-trivial configurations of the hypermagnetic flux lines lead to the formation of hypermagnetic knots (HK) whose decay might seed the Baryon Asymmetry of the Universe (BAU).HK can be dynamically generated provided a topologically trivial (i.e. stochastic) distribution of flux lines is already present in the symmetric phase of the electroweak

Norma Mankoc Borstnik, Holger Bech Nielsen, Colin Froggatt

The Proceedings collects the results of ten days of discussions on the open questions of the Standard electroweak model as well as the review of the introductory talks, connected with the discussions.

Daniel Sanchez-Portal, Emilio Artacho, Javier Junquera, Pablo Ordejon

Using first principles density functional calculations, gold monatomic wires are found to exhibit a zigzag shape which remains under tension, becoming linear just before breaking. At room temperature they are found to spin, what explains the extremely long apparent interatomic distances shown by electron microscopy.The zigzag structure is stable if the tensi

N. Stefanakis, N. Flytzanis

The magnetic interference pattern and the spontaneous flux in unconventional Josephson junctions of superconductors with d+is symmetry are calculated for different reduced junction lengths and the relative factor of the d and s wave components. This is a time reversal broken symmetry state. We study the stability of the fractional vortex and antivortex which

U. T. Schwarz, L. Q. English, A. J. Sievers

By driving with a microwave pulse the lowest frequency antiferromagnetic resonance of the quasi 1-D biaxial antiferromagnet (C_2 H_5 NH_3)_2 CuCl_4 into an unstable region intrinsic localized spin waves have been generated and detected in the spin wave gap. These findings are consistent with the prediction that nonlinearity plus lattice discreteness can lead

W. A. Lawson

We examine long-term low-dispersion IUE, SWP and LWP spectroscopy of the R Coronae Borealis (RCB) star V854 Cen, obtained across the deep 1991, 1992-1993 and 1994 declines. We also report the optical light curve for the star in the interval 1987-1998, including multi-color photometry obtained during 1989-1998. Analysis of the UV emission line spectra indicat

Igor R. Klebanov, Edward Witten

We study, using the dual AdS description, the vacua of field theories where some of the gauge symmetry is broken by expectation values of scalar fields. In such vacua, operators built out of the scalar fields acquire expectation values, and we show how to calculate them from the behavior of perturbations to the AdS background near the boundary. Specific exam

E. P. Mazets, T. L. Cline, R. L. Aptekar, P. Butterworth

Results are presented of the observations of the soft gamma repeater SGR 1900+14 made on the Wind spacecraft during the source reactivation period from May 1998 to January 1999. Individual characteristics of recurrent bursts, such as their time histories, energy spectra, and maximum and integrated energy fluxes, are considered. Some statistical distributions

H. Furutsu, T. Kojima

We study $U_q(\hat{sl}_n)$ analog of the XXZ spin chain with a boundary magnetic field h. We construct explicit bosonic formulas of the vacuum vector and the dual vacuum vector with a boundary magnetic field. We derive integral formulas of the correlation functions.

A. J. S. Hamilton

Nonlinear evolution causes the galaxy power spectrum to become broadly correlated over different wavenumbers. It is shown that prewhitening the power spectrum - transforming the power spectrum in such a way that the noise covariance becomes proportional to the unit matrix - greatly narrows the covariance of power. The eigenfunctions of the covariance of the

A. J. S. Hamilton, Max Tegmark

It is shown how to decorrelate the (prewhitened) power spectrum measured from a galaxy survey into a set of high resolution uncorrelated band-powers. The treatment includes nonlinearity, but not redshift distortions. Amongst the infinitely many possible decorrelation matrices, the square root of the Fisher matrix, or a scaled version thereof, offers a partic

A. A. Zhmudsky

The exact solution of radiation problem of a spin wave travelling in an antiferromagnetic (AFM) plate was found. The spin wave with in-plane oscillations of antiferromagnetism vector was considered. In this case the magnetization vector is oscillating being perpendicular to the AFM plate and depends on time and plane coordinates as travelling wave does. This

Ian G. Moss

The quantum properties of solitons at one loop can be related to phase shifts of waves on the soliton background. These can be combined with heat kernel methods to calculate various parameters. The vacuum energy of a CP(1) soliton in 2+1 dimensions is calculated as an example.

Aldo Deandrea

I consider a model for heavy meson decays based on an effective quark-meson Lagrangian. The model is constrained by the known symmetries of QCD in the m_Q -> infinity limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the lept

T. Hahn

A set of programs is presented for automatically generating and calculating Feynman diagrams. Diagrams are generated with FeynArts, then algebraically simplified using a combination of Mathematica and FORM implemented in the package FormCalc, and finally evaluated numerically using the LoopTools package. FormCalc works either in dimensional regularization or

Dong-Won Jung, Kang Young Lee, H. S. Song, Chaehyun Yu

We perform the comprehensive analysis of the polarization effects on the e^+e^- -> W^+W^- process in the presence of the extra neutral gauge boson at the LC energies. Consideration of the polarizations of the produced W bosons and the beam polarizations provides substantial enhancements of the sensitivity to the Z-Z&#39; mixing angles in various models and t

R. Mansouri, F. Nasseri, M. Khorrami

Time variation of Newtonian gravitational constant, $G$, is studied in the model universe with variable space dimension proposed recently. Using the Lagrangian formulation of these models, we find the effective gravitational constant as a function of time. To compare it with observational data, a test theory for the time variation of $G$ is formulated. We ha

Hans - Juergen Schmidt

The solutions of two-dimensional gravity following from a non-linear Lagrangian L = f(R) are classified, and their symmetry and singularity properties are described. Then a conformal transformation is applied to rewrite these solutions as analogous solutions of two-dimensional Einstein-dilaton gravity and vice versa.

Toru Sakai, Shoji Yamamoto

We numerically investigate the critical behavior of the spin-(1,1/2) Heisenberg ferrimagnet with anisotropic exchange coupling in a magnetic field. A quantized magnetization plateau as a function of the field, appearing at a third of the saturated magnetization, is stable over whole the antiferromagnetic coupling region. The plateau vanishes in the ferromagn

Erick Lee, Jeremy Goodman

Single-armed, stationary density waves can propagate in very weakly self-gravitating gas disks dominated by a central mass. Examples include circumstellar disks of protostars and molecular disks in galactic nuclei. We explore the linear and nonlinear dynamics of such waves. Variational methods yield nonlinear versions of the dispersion relation, angular mome

Yasushi Ikebe, Kazuo Makishima, Yasushi Fukazawa, Takayuki Tamura

ASCA and ROSAT data of the Centaurus cluster were analyzed. A central excess in the radial brightness profile is found in the hard energy band up to 10keV. This requires a deeper central potential than a King-type one. A double-beta brightness distribution gives a good account of the data. A deprojected energy spectrum within a spherical region of radius 30

R. T. Rood, E. Carretta, B. Paltrinieri, F. R. Ferraro

We present a high precision, large sample luminosity function (LF) for the Galactic globular cluster M3. With a combination of ground based and Hubble Space Telescope data we cover the entire radial extent of the cluster. The observed LF is well fit by canonical standard stellar models from the red giant branch (RGB) tip to below the main sequence turnoff po

Michael C. Liu, Stephane Charlot, James R. Graham

We are using optical/IR surface brightness fluctuations (SBFs) to validate the latest stellar population synthesis models and to understand the stellar populations of ellipticals. Integrated light and spectra measure only the first moment of the stellar luminosity function (Σn_i * L_i). Since SBFs also depend on the second moment (Σn_i * L_i^2), they provide

R. J. M. Covolan, M. S. Soares

Hadronic processes in which hard diffractive production takes place have been observed and analyzed in collider experiments for several years. The experimental rates of diffractive W&#39;s and dijets measured at the Tevatron and the cross sections of diffractively produced dijets recently obtained at the HERA experiment are the object of this analysis. We us

Andre&#39; LeClair

We consider the effects of disorder in a Dirac-like Hamiltonian. In order to use conformal perturbation theory, we argue that one should consider disorder in an imaginary vector potential. This affects significantly the signs of the lowest order $β$eta functions. We present evidence for the existence of two distinct universality classes, depending on the rel

F. De Fazio, M. Neubert

An analytic result for the O(alpha_s corrections to the triple differential B -> X_u l nu decay rate is presented, to leading order in the heavy-quark expansion. This is relevant for computing partially integrated decay distributions with arbitrary cuts on kinematic variables. Several double and single differential distributions are derived, most of which ge

O. Aharony, S. S. Gubser, J. Maldacena, H. Ooguri

We review the holographic correspondence between field theories and string/M theory, focusing on the relation between compactifications of string/M theory on Anti-de Sitter spaces and conformal field theories. We review the background for this correspondence and discuss its motivations and the evidence for its correctness. We describe the main results that h

D0 Collaboration, B. Abbott

We present measurements of the b-bbar production cross section and angular correlations using the D0 detector at the Fermilab Tevatron p-pbar Collider operating at sqrt(s) = 1.8 TeV. The b quark production cross section for |y(b)|<1.0 and p_T(b)>6 GeV/c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading

J. L. Boldo, J. A. Helayel-Neto, N. Panza

In this paper, fermions are minimally coupled to 3D-gravity where a dynamical torsion is introduced. A Kalb-Ramond field is non-minimally coupled to these fermions in a gauge-invariant way. We show that a 1-loop mass generation mechanism takes place for both the 2-form gauge field and the torsion. As for the fermions, no mass is dynamically generated: at 1-l

M. Benayoun, L. DelBuono, H. B. O&#39;Connell

We show that the Hidden Local Symmetry Model, supplemented with well-known procedures for breaking flavor SU(3) and nonet symmetry, provides all the information contained in the standard Chiral Perturbation Theory (ChPT) Lagrangian ${\cal L}^{(0)}+{\cal L}^{(1)}$. This allows to rely on radiative decays of light mesons ($VPγ$ and $P γγ$) in order to extract

S. J. Hatton, S. Cole

Given the failure of existing models for redshift-space distortions to provide a highly accurate measure of the beta-parameter, and the ability of forthcoming surveys to obtain data with very low random errors, it becomes necessary to develop better models for these distortions. Here we review the failures of the commonly-used velocity dispersion models and

J. M. Udias, J. A. Caballero, E. Moya de Guerra, J. E. Amaro

Predictions for electron induced proton knockout from the $p_{1/2}$ and $p_{3/2}$ shells in $^{16}$O are presented using various approximations for the relativistic nucleonic current. Results for the differential cross section, transverse-longitudinal response ($R_{TL}$) and left-right asymmetry $A_{TL}$ are compared at $|Q^2|=0.8$ (GeV/c)$^2$ corresponding

Felix Finster, Niky Kamran, Joel Smoller, Shing-Tung Yau

We prove that, in the non-extreme Kerr-Newman black hole geometry, the Dirac equation has no normalizable, time-periodic solutions. A key tool is Chandrasekhar&#39;s separation of the Dirac equation in this geometry. A similar non-existence theorem is established in a more general class of stationary, axisymmetric metrics in which the Dirac equation is known

Luis E. Ibanez

We use compact D=4, N=1, Type IIB orientifolds as a testing ground for recent ideas about precocious gauge coupling unification and a low energy string scale. We find that certain such orientifolds have the interesting property that gauge couplings receive moduli-dependent corrections which mimic the effect of field theoretical logarithmic running. The effec

Andrea Gabrielli, Francesco Sylos Labini, Ruth Durrer

In this letter we show that in a Gaussian random field the correlation length, the typical size of correlated structures, does not change with biasing. We interpret the amplification of the correlation functions of subsets identified by different thresholds being due to the increasing sparseness of peaks over threshold. This clarifies an long-standing miscon

Gustavo Burdman

We study the production and decay of neutral scalars and pseudo-scalars at hadron colliders, in theories where the top-quark mass is the result of a $t\bar t$ condensate. We show that the dominant decay channel for masses below the $t\bar t$ threshold is the flavor changing mode $tc$. This is a consequence of the non-universal nature of the underlying intera

B. M. Zupnik

The superfield models with the partial spontaneous breaking of the global D=3, N=2 supersymmetry are discussed. The abelian gauge model describes low-energy interactions of the real scalar field with the 3D vector and fermion fields. We introduce the new Goldstone-Maxwell representation of the 3D gauge superfield and show that the partial spontaneous breakin

Shin-ya Nitta

The aim of this work is to demonstrate the properties of the magnetospheric model around Kerr blackholes (BHs), so-called the fly-wheel (rotation driven) model. The fly-wheel engine of the BH-accretion disk system is applied to the statistics of QSOs/AGNs. In the model, the central BH is assumed to be formed at $z \sim 10^2$ and obtains nearly maximum but fi