September 1999 arXiv papers — page 15

T. W. Murphy,, B. T. Soifer, K. Matthews, J. R. Kiger

Near infrared spectra with resolution R ~ 1100 in the rest wavelength range 1.8-2.2 microns have been obtained for a complete sample of 33 ultraluminous infrared galaxies. Of the 33 objects observed, 2 show evidence of a central AGN through either a broad Paschen-alpha line or emission in the 1.963 micron fine structure of [Si VI]. In the median spectrum of

P. G. Tinyakov

It is argued that if extragalactic magnetic fields are smaller than 2x10^{-12} G the flux of ultra-high energy photons of (a few)x10^{-1} eV cm^{-2}s^{-1}sr^{-1} predicted in the top-down models of UHE CR implies similar flux of the diffuse photons in the energy range 10^{15}-10^{17} eV, which is close to the existing experimental limit.

Mark Henriksen, R. Hank Donnelly, David S. Davis

A temperature map of the A3266 galaxy cluster has been derived from the ASCA GIS observations. It shows an asymmetric pattern of heating indicative of an ongoing merger between a group sized sub-cluster and the main cluster. The galaxy distribution shows two peaks connected in a barlike structure running NE to SW through the central region of the main cluste

J. E. Pringle, R. R. J. Antonucci, C. J. Clarke, A. L. Kinney

We demonstrate that, by combining optical, radio and X-ray observations of a Seyfert, it is possible to provide a direct measurement of the angle $β$ between the direction of the radio jet and the normal to the plane of the spiral host galaxy. To do so, we make the assumptions that the inner radio jet is perpendicular to the X-ray observed inner accretion di

P. Giommi, E. Massaro, L. Chiappetti, E. C. Ferrara

We report intensity variations of different spectral components in the BL Lac object S5 0716+714 detected during coordinated BeppoSAX and optical observations in 1996 and 1998. The transition between synchrotron and inverse Compton emission has been clearly detected as sharp X-ray spectral breaks at around 2-3 keV on both occasions. Correlated optical and so

Vesna Milosevic-Zdjelar, Srdjan Samurovic, Milan M. Cirkovic

Microlensing observations can be used for determining the shape of the Milky Way&#39;s halo. It can be shown that the data are best described with moderately flattened halo, 0.5 < q < 0.6. We discuss, by taking into account this result, the constraints on the baryonic mass-density parameter, $Ω_B$, and their implications on the value of the Hubble constant $

Milan M. Cirkovic, Srdjan Samurovic, Vesna Milosevic-Zdjelar

One of the biggest obstacles to our full understanding of the global dynamics in Milky Way and other spiral galaxies is uncertainty with respect to the form of baryonic dark matter in galactic haloes. Two basic forms discussed recently are MACHOs and various states of halo gas. We investigate constraints which could be obtained from the empirical microlensin

Thomas W. Baumgarte, Stuart L. Shapiro

We launch a fully relativistic study of the formation of supermassive black holes via the collapse of supermassive stars. Here we initiate our investigation by analyzing the secular evolution of supermassive stars up to the onset of dynamical instability and collapse. We focus on the effects of rotation, assumed uniform, and general relativity. We identify t

Thomas W. Baumgarte, Stuart L. Shapiro

We determine the effect of rotation on the luminosity of supermassive stars. We apply the Roche model to calculate analytically the emitted radiation from a uniformly rotating, radiation-dominated supermassive configuration. We find that the luminosity at maximum rotation, when mass at the equator orbits at the Kepler period, is reduced by ~36% below the usu

M. Balucinska-Church, M. J. Church, P. A. Charles, F. Nagase

We present results of a comprehensive study of the distribution of absorption dips with orbital phase in Cygnus X-1. Firstly, the distribution was obtained using archival data from all major X-ray observatories and corrected for the selection effect that phase zero (superior conjunction of the black hole) has been preferentially observed. Dip occurrence was

Arjun Berera, Paul A. Martin

The (ordinary) Sachs-Wolfe effect relates primordial matter perturbations to the temperature variations $δT/T$ in the cosmic microwave background radiation; $δT/T$ can be observed in all directions around us. A standard but idealised model of this effect leads to an infinite set of moment-like equations: the integral of $P(k) j_\ell^2(ky)$ with respect to k

R. K. Zamanov, J. Marti, J. M. Paredes, J. Fabregat

We present the results of analyzing H$α$ spectra of the radio emitting X-ray binary LS I+61303. For the first time, the same 26.5 d radio period is clearly detected in the H$α$ emission line. Moreover, the equivalent width and the peak separation of the H$α$ emission line seem also to vary over a time scale of 1600 days. This points towards the $\sim4$ yr mo

A. Lopez Ariste, M. Semel

A new formalism is introduced for the transfer of polarized radiation. Stokes parameters are shown to be four-vectors in a Minkowski-like space and, most strikingly, the radiative transfer equation (RTE) turns out to be an infinitesimal transformation under the Poincare (plus dilatations) group. A solution to the transfer equation as a finite element of this

R. A. Battye, E. P. S. Shellard

Understanding axion cosmology has important experimental consequences since it constrains the range of allowed values for the axion mass. In the standard thermal scenario, which assumes Peccei-Quinn symmetry restoration after inflation, an axion string network forms at the phase transition $T\sim\fa$ and then radiatively decays into a cosmological background

M. A. Beasley, R. M. Sharples

We have obtained spectra for 103 published globular cluster candidates in the Sculptor Group galaxies NGC 253 and NGC 55. On the basis of radial velocities and digitized plate images, 14 globular clusters are identified in NGC 253 and one probable globular cluster is identified in NGC 55. The majority of the objects in the sample appear to be background gala

G. B. Deineka

A two-dimensional, fully numerical approach to the solution of four-component Dirac-Fock equation using the moderately long Hermitian basis of B-splines is applied to H, H2+ and H2 in a strong magnetic field. The geometric parameters, including different behavior of wave-functions relativistic components are analyzed. The accuracy of the solutions as a funct

S. Molendi, S. De Grandi, R. Fusco-Femiano, S. Colafrancesco

We present results from a BeppoSAX observation of the rich cluster Abell 2319. The broad band spectrum (2-50 keV) of the cluster can be adequately represented by an optically thin thermal emission model with a temperature of 9.6+/-0.3 keV and a metal abundance of 0.25+/-0.03 in solar units, and with no evidence of a hard X-ray excess in the PDS spectrum. Fro

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod

The MACHO Project is a microlensing survey that monitors the brightnesses of 60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photomet

D. W. Sciama

We explore further the proposal in paper I of this series that the confinement time of cosmic ray nuclei in the Milky Way is determined by their interaction with dark matter molecular clouds rather than by their escape from the halo, as is assumed in conventional models of cosmic ray propagation. The same proposal can be made for cosmic ray electrons. This p

Jakob T. Simonsen, Steen Hannestad

Recent measurements of type Ia supernovae indicate that distant supernovae are substantially fainter than expected from the standard flat cold dark matter model. One possible explanation is that the energy density in our universe is in fact dominated by a cosmological constant. Another possible solution is that there are large amounts of grey dust in the int

Hideko Nomura, Hideyuki Kamaya, Shin Mineshige

We consider the propagation of hydromagnetic waves generated by a compact turbulent source in low ionized plasmas, applying the Lighthill theory. We assume the plasma to be isothermal, and adopt a uniform, stationary medium thread by ordered magnetic fields as an initial condition. Then, the distinct properties of the hydromagnetic waves originating from a s

S. Andreon

The UV (2000 A) luminosity function (hereafter UV LF) of Coma cluster galaxies, based on more than 120 members, is computed as the statistical difference between counts in the Coma direction and in the field. Our UV LF is an up-date of a preliminary constrain on the UV LF previously computed without the essential background counts. The UV LF is well describe

Daniel D. Kelson, Garth D. Illingworth, John L. Tonry, Wendy L. Freedman

Using published photometry and spectroscopy, we construct the fundamental plane and D_n-Sigma relations in Leo I, Virgo and Fornax. The published Cepheid P-L relations to spirals in these clusters fixes the relation between angular size and metric distance for both the fundamental plane and D_n-Sigma relations. Using the locally calibrated fundamental plane,

Xiangdong Shi, George M. Fuller, Kevork Abazajian

This is a reply to the preprint &#34;On Neutrino-Mixing-Generated Lepton Asymmetry and the Primordial Helium-4 Abundance&#34; by M. V. Chizhov and D. P. Kirilova (hep-ph/9908525), which criticised our recent publication (X. Shi, G. M. Fuller and K. Abazajian Phys. Rev. D 60, 063002 (1999)). Here we point out factual errors in their description of what our pa

Robert Kehoe, Carl Akerlof, Richard Balsano, Scott Barthelmy

The Robotic Optical Transient Search Experiment (ROTSE) seeks to measure contemporaneous and early afterglow optical emission from gamma-ray bursts (GRBs). The ROTSE-I telescope array has been fully automated and responding to burst alerts from the GRB Coordinates Network since March 1998, taking prompt optical data for 30 bursts in its first year. We will b

Geoffrey V. Bicknell, Ralph S. Sutherland, Wil J. M. van Breugel, Michael A. Dopita

The high redshift radio galaxy 4C41.17 consists of a powerful radio source in which previous work has shown that there is strong evidence for jet-induced star formation along the radio axis. We argue that nuclear photoionization is not responsible for the excitation of the emission line clouds and we construct a jet-cloud interaction model to explain the maj

R. J. Protheroe, W. Bednarek

Some gamma ray bursts may be produced by supernovae exploding in close massive binary systems (type Ib/c supernovae) as suggested by the recent observation of SN 1998bw/GRB 980425. We propose that high energy radiation observed in such gamma ray bursts may be produced by synchrotron radiation of electrons accelerated by 1st order Fermi acceleration at a quas

Finn Larsen, Emil Martinec

We consider black strings in five dimensions and their description as a (4,0) CFT. The CFT moduli space is described explicitly, including its subtle global structure. BPS conditions and global symmetries determine the spectrum of charged excitations, leading to an entropy formula for near-extreme black holes in four dimensions with arbitrary charge vector.

Bruce A. Bassett, F. Viniegra

Can super-Hubble metric perturbations be amplified exponentially during preheating ? Yes. An analytical existence proof is provided by exploiting the conformal properties of massless inflationary models. The traditional conserved quantity ζis non-conserved in many regions of parameter space. We include backreaction through the homogeneous parts of the inflat

Elizabeth J. Barton, Margaret J. Geller, Scott J. Kenyon

We analyze new optical spectra of a sample of 502 galaxies in close pairs and n-tuples, separated by <= 50/h kpc. We extracted the sample objectively from the CfA2 redshift survey, without regard to the surroundings of the tight systems. We probe the relationship between star formation and the dynamics of the systems of galaxies. The equivalent widths of Hα(

Gordon Chalmers, Koenraad Schalm

We rewrite the SL(2,Z) covariant worldsheet action for the IIB string proposed by Townsend in a Polyakov form. In a flat background the formalism yields separate (p,q) sectors. In each one the action is that of the IIB string action with the string slope parameter \alp\pr replaced by its SL(2,Z) analogue \alp_{pq}\pr. SL(2,Z) invariant graviton scattering am

Kenneth Intriligator

We discuss four dimensional renormalization group flows which preserve sixteen supersymmetries. In the infra-red, these can be viewed as deformations of the N=4 superconformal fixed points by special, irrelevant operators. It is argued that the gauge coupling beta function continues to vanish identically, for all coupling constants and energy scales, for suc

V. Frolov, P. Sutton, A. Zelnikov

In a wide class of D-dimensional spacetimes which are direct or semi-direct sums of a (D-n)-dimensional space and an n-dimensional homogeneous ``internal&#39;&#39; space, a field can be decomposed into modes. As a result of this mode decomposition, the main objects which characterize the free quantum field, such as Green functions and heat kernels, can effec

Miao Li, Yong-Shi Wu

In this note a lately proposed gravity dual of noncommutative Yang-Mills theory is derived from the relations, recently suggested by Seiberg and Witten, between closed string moduli and open string moduli. The only new input one needs is a simple form of the running string tension as a function of energy. This derivation provides convincing evidence that str

S. M. Viegas, R. Gruenwald, G. Steigman

Helium and hydrogen recombination lines observed in low-metallicity, extragalactic H II regions provide the data used to infer the primordial helium mass fraction, Y_P. The ionization corrections for unseen neutral helium (or hydrogen) are usually assumed to be absent; i.e., the ionization correction factor is taken to be unity (icf = 1). In this paper we re

Chris Dawson

The viability of the Non-Perturbative Renormalisation (NPR) method of the Rome/Southampton group is studied, for the first time, in the context of domain wall fermions. The procedure is used to extract the renormalisation coefficients of the various quark bilinears, as well as the four-fermion operators relevant to the $ΔS=2$ effective Hamiltonian. The renor

P. B. Wiegmann

I review a recent progress towards solution of the Almost Mathieu equation (A.G. Abanov, J.C. Talstra, P.B. Wiegmann, Nucl. Phys. B 525, 571, 1998), known also as Harper&#39;s equation or Azbel-Hofstadter problem. The spectrum of this equation is known to be a pure singular continuum with a rich hierarchical structure. Few years ago it has been found that th

R. Rapp, E. Shuryak

We investigate the significance of thermal dilepton radiation in the intermediate-mass region in heavy-ion reactions at CERN-SpS energies. Within a thermal fireball model for the space-time evolution, the radiation from hot matter is found to dominate over hard &#39;background&#39; processes (Drell-Yan and open charm) up to invariant masses of about 2 GeV, w

Tullio Regge, Riccardo Zecchina

We extend the planar Pfaffian formalism for the evaluation of the Ising partition function to lattices of high topological genus g. The 3D Ising model on a cubic lattice, where g is proportional to the number of sites, is discussed in detail. The expansion of the partition function is given in terms of 2^{2 g} Pfaffians classified by the oriented homology cy

D0 Collaboration

We present a measurement of the transverse momentum distribution of Z bosons produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider during 1994--1996. We find good agreement between our data and a current resummation calculation. We also use our data to extract values of the non-perturbativ

Peter Borrmann, Oliver Muelken, Jens Harting

We present a classification scheme for phase transitions in finite systems like atomic and molecular clusters based on the Lee-Yang zeros in the complex temperature plane. In the limit of infinite particle numbers the scheme reduces to the Ehrenfest definition of phase transitions and gives the right critical indices. We apply this classification scheme to B

M. Hassaïne P. A. Horváthy, J. -C. Yéra

The spacelike reduction of the Chern-Simons Lagrangian yields a modified Nonlinear Schrödinger Equation (jNLS) where in the non-linearity the particle density is replaced by current. When the phase is linear in the position, this latter is an ordinary NLS with time-dependent coefficients which admits interesting solutions, whose arisal is explained by the co

J. R. Stauffer, D. Barrado y Navascués, J. Bouvier, H. L. Morrison

We have identified twenty-seven candidate very low mass members of the relatively young Alpha Persei open cluster from a six square degree CCD imaging survey. Based on their I magnitudes and the nominal age and distance to the cluster, these objects should have masses less than 0.1 Msunif they are cluster members. We have subsequently obtained intermediate r

Rong-Gen Cai

We study the dynamics and thermodynamics of a probe D3-brane in the rotating D3-brane background and in its extremal limit, which is a multicenter configuration of D3-branes distributed uniformly on a disc. In the extremal background, if the angular momentum of the probe does not vanish, the probe is always bounced back at some turning point. When its angula

Hisaki Hatanaka, Makoto Sakamoto, Motoi Tachibana, Kazunori Takenaga

Recently, Randall and Sundrum proposed a static solution to Einstein&#39;s equations in five spacetime dimensions with two 3-branes located at the fixed points of $S^1/Z_2$ to solve the hierarchy problem. We extend the solution and construct static and also inflationary solutions to Einstein&#39;s equations in five spacetime dimensions, one of which is compa

Robert R. Tucci

The main goal of this paper is to give a pedagogical introduction to Quantum Information Theory-to do this in a new way, using network diagrams called Quantum Bayesian Nets. A lesser goal of the paper is to propose a few new ideas, such as associating with each quantum Bayesian net a very useful density matrix that we call the meta density matrix.

Ch. Roos, Th. Zeiger, H. Rohde, H. C. Naegerl

A single Ca+ ion in a Paul trap has been cooled to the ground state of vibration with up to 99.9% probability. Starting from this Fock state |n=0> we have demonstrated coherent quantum state manipulation on an optical transition. Up to 30 Rabi oscillations within 1.4 ms have been observed. We find a similar number of Rabi oscillations after preparation of th

S. J. Childs, F. A. Shillington

Examples of heavy mineral placer deposits are presented in which wave reflection, refraction, diffraction and resonance would appear to have played a major concentrating role. Their geometry is compared with the computer generated patterns predicted for the reflection, refraction and diffraction of surface waves moving over fairly simple, idealised bathymetr

L. Berge, O. Bang, W. Krolikowski

Four-wave mixing and walk-off between two optical beams are investigated for fo cusing Kerr media. It is shown that four-wave mixing reinforces the self-focusi ng of mutually-trapped waves by lowering their power threshold for collapse, on ly when their phase mismatch is small. On the contrary, walk-off inhibits the c ollapse by detrapping the beams, whose p

F. M. Lev, E. Pace, G. Salme`

In front-form dynamics a current operator for systems of interacting particles, which fulfills Poincaré, parity and time reversal covariance, together with hermiticity, can be defined. The electromagnetic form factors can be extracted without any ambiguity and in the elastic case the continuity equation is automatically satisfied. Applications to the calcula

E. Garrido, P. Sarriguren, E. Moya de Guerra, P. Schuck

Effective density dependent pairing forces of zero range are adjusted on gap values in T=0,1 channels calculated with the Paris force in symmetric nuclear matter. General discussions on the pairing force are presented. In conjunction with the effective k-mass the nuclear pairing force seems to need very little renormalization in the T=1 channel. The situatio

E. Pace, G. Salme`, F. Cardarelli, S. Simula

A review of the hadron electromagnetic form factors obtained in a light-front constituent quark model, based on the eigenfunctions of a mass operator, is presented. The relevance of different components in the q-q interaction for the description of hadron experimental form factors is analysed.

A. Sibirtsev, W. Cassing

We study the antikaon potential at finite momentum for proton and neutron nuclear matter. Our approach is based on the momentum dependence of the real part of the total $K^-N$ scattering amplitude, which is fixed in free space by experimental data, using the dispersion relation approach. We decompose the contributions to the scattering amplitude from differe

WA98 Collaboration, H. Schlagheck

The WA98 experiment at the CERN SPS measures Pb+Pb Collisions at 158 AGeV. The scaling properties of the charged particle multiplicity at midrapidity with the number of participants are studied using the SPMD and the MIRAC detector. Neutral pion spectra obtained from the LEDA detector are compared to hydrodynamical parametrizations. The collective flow in th

Horia Scutaru

A sharp estimation of the $L^p$-norms of some matrix coefficients of the square integrable representations is conjectured. The conjecture can be proved for integer values of $p$ using a result of J. Burbea.

Jean Marie Linhart

We study singularity formation in spherically symmetric solitons of the (4+1) dimensional Yang Mills model and the charge two sector of the (2+1) dimensional S^2 sigma model, also known as $\IC P^1$ wave maps, in the adiabatic limit. These two models are very similar. Studies are performed numerically on radially symmetric solutions using an iterative finite

Michael W. Davis, Boris Okun, Fangyang Zheng

In this article, we generalize Eberlein&#39;s Rigidity Theorem to the singular case, namely, one of the spaces is only assumed to be a CAT(0) topological manifold. As a corollary, we get that any compact irreducible but locally reducible locally symmetric space of noncompact type does not admit a nonpositively curved (in the Aleksandrov sense) piecewise Eucl

J. Grabowski, G. Marmo, P. W. Michor

Pulling back sets of functions in involution by Poisson mappings and adding Casimir functions during the process allows to construct completely integrable systems. Some examples are investigated in detail.

David De Wit

The ``Links-Gould invariant&#39;&#39; is a two-variable Laurent polynomial invariant of oriented (1,1) tangles, which is derived from the representation of the braid generator associated with the one-parameter family of four dimensional representations with highest weights (0,0|a) of the quantum superalgebra U_q[gl(2|1)]. We use an abstract tensor state mode

Alan Weinstein

We define a C^1 distance between submanifolds of a riemannian manifold M and show that, if a compact submanifold N is not moved too much under the isometric action of a compact group G, there is a G-invariant submanifold C^1-close to N. The proof involves a procedure of averaging nearby submanifolds of riemannian manifolds in a symmetric way. The procedure c

Valeri V. Dvoeglazov, Sergei V. Khudyakov

In the old papers of Ogievetskii and Polubarinov, Hayashi, Kalb and Ramond the {\it notoph} concept, the longitudinal field originated from the antisymmetric tensor, has been proposed. In our work we analyze the theory of antisymmetric tensor field of the second rank from a viewpoint of the normalization problem. We obtain the 4-potentials and field strength

L. Cornalba

We discuss the physics of a single Dp-brane in the presence of a background electromagnetic field B_{ij}. It has recently been shown \cite{SW} that, in a specific α&#39; \to 0 limit, the physics of the brane is correctly described by noncommutative Yang-Mills theory, where the noncommutative gauge potential is given explicitly in terms of the ordinary U(1) f

Pedro J. Silva

We study the significance of T-duality in the context of the gravitational description of gauge theories. We found that T-duality relates the deferents points of the moduli of a given gauge theory always far from the conformal fixed point. Also the described gauge theories seems to flow naturally to the able conformal points, those that naturally saturate al

D. Diakonov, M. Maul

We introduce an explicit form of the multi-instanton weight including also instanton--anti-instanton interactions for arbitrary $N_c$ in the two-dimensional $CP^{N_c-1}$ model. To that end, we use the parametrization of multi-instantons in terms of instanton `constituents&#39; which we call `zindons&#39; for short. We study the statistical mechanics of zindo

B. Chen, H. Itoyama, H. Kihara

We study the expectation value of (the product) of the one-particle projector (s) in the reduced matrix model and matrix quantum mechanics in general. This quantity is given by the nonabelian Berry phase: we discuss the relevance of this with regard to the spacetime structure. The case of the USp matrix model is examined from this respect. Generalizing our p

Sascha Vongehr

Two time theory is derived via localization of the global Sp(2) [or Osp(1/2), Osp(N/2), Sp(2N),...] symmetry in phase space in order to give a self contained introduction to two time theory. Then it is shown that from the two-times physics point of view theories of point particles on many known black hole backgrounds are Sp(2) gauge duals of one another and

Tim M. P. Tait

The t W- mode of single top production is proposed as an important means to study the weak interactions of the top quark. While the rate of this mode is most likely too small to be observed at Run II of the Fermilab Tevatron, it is expected to be considerably larger at the CERN LHC. In this article the inclusive t W- rate is computed, including O(1 / log (m_

S. Kabana, P. Minkowski

The present discussion focusses on the dominant production of the 0++ glueball in central collisions in the suppressed yet observable channel 0++ --> pi+ pi- l+ l-.

Glenn D. Starkman, Dejan Stojkovic

We consider the most general neutrino masses and mixings including Dirac mass terms, M_D, as well as Majorana masses, M_R and M_L. Neither the Majorana nor the Dirac mass matrices are expected to be diagonal in the eigenbasis of weak interactions, and so the resulting eigenstates of the Hamiltonian are admixtures of $\SU(2)_L$ singlet and doublet fields of d

Uri Sarid, Scott Thomas

The phenomenological implications of supersymmetric theories with low scale supersymmetry breaking and a squark as the lightest standard model superpartner are investigated. Such squarks hadronize with light quarks, forming sbaryons and mesinos before decaying. Production of these supersymmetric bound states at a high energy collider can lead to displaced je

A. A. Natale

We discuss how the vacuum model of Celenza and Shakin with a squeezed gluon condensate can explain the existence of an infrared singular gluon propagator frequently used in calculations within the global colour model. In particular, it reproduces a recently proposed QCD-motivated model where low energy chiral parameters were computed as a function of a dynam

T. Sjöstrand, M. H. Seymour

An overview is given of general-purpose event generators, especially PYTHIA and HERWIG. The current status is summarized, some recent physics improvements are described, and planned future projects are outlined.

O. Vives

In this work, we study possible new contributions to $ε_{K}$ and $ε_{B}$ in the MSSM with large supersymmetric phases. We show that, in the CMSSM, the constrains coming from the experimental measure of the $b \to s γ$ decay imply that these contributions are too small to be detected in CP violation experiments with the available sensitivity.

J. Bartels, M. G. Ryskin

The nonsinglet spin dependent structure function $g_2(x,Q^2)$ is studied at small x within the double logarithmic approximation of perturbative QCD. Both positive and negative signature contributions are considered, and we find a power-like growth in $1/x$. We discuss how our result fits into the Wandzura-Wilczek relation.

E. Gotsman

We show that when screening corrections are included $\frac{\partial F_{2}(x,Q^{2})}{\partial ln(Q^{2}/Q_{0}^{2})}$ is consistent with the behaviour that one expects in pQCD. Screening corrections explain the enigma of the Caldwell plot. Saturation has not been reached at present HERA energies.

T. N. Pham

The measurement of CP asymmetries in charged B meson decays might provide the first demonstration of CP violation outside the K system. Among the usual three CP-odd phases $α$, $β$ and $γ$, the phase $γ$ seems to be the most difficult to explore experimentally. In this talk I would like to report on a recent analysis of the CP asymmetry in the partial widths

W. Grimus, S. Mohanty, P. Stockinger

We discuss conceptual aspects of neutrino oscillations with the main emphasis on the field-theoretical approach. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source - detection process. In this context

C. Carimalo, W. da Silva, F. Kapusta

The total cross-section of the $γγ\to 4 $ leptons process is known to have a large constant value at high energy, but a complete and exact calculation of related differential spectra does not exist yet. However a complete study of the process is important at NLC for luminosity measurements or for background estimations. We here report on our various steps in

A. Ringwald, F. Schrempp

We review our on-going theoretical and phenomenological investigation of the prospects to discover QCD-instantons in deep-inelastic scattering at HERA.

V. V. Kiselev, A. I. Onishchenko

The masses of baryons containing two heavy quarks and their couplings to the corresponding quark currents are evaluated in the framework of NRQCD sum rules. The coulomb-like corrections in the system of doubly heavy diquark are taken into account, and the contribution of nonperturbative terms coming from the quark, gluon and mixed condensates as well as the

D. J. Broadhurst

Dyson-Schwinger equations are used to evaluate the 4-loop anomalous dimensions of quenched QED in terms of finite, scheme-independent, 3-loop integrals. Three of the results serve as strong checks of terms from scheme-dependent 4-loop QCD calculations. The fourth, for the anomalous dimension of $\barψσ_{μν}ψ$, was previously known only to 2-loop order. The 4

Howard E. Haber, Heather E. Logan

We explore the radiative corrections to the process $Z \to b \bar b$ in models with extended Higgs sectors. The observables $R_b = Γ(Z \to b \bar b)/Γ(Z \to \rm{hadrons})$ and the $Z b \bar b$ coupling asymmetry, $A_b = (g_L^2 - g_R^2)/(g_L^2 + g_R^2)$, are sensitive to these corrections. We present general formulae for the one-loop corrections to $R_b$ and

Nima Arkani-Hamed, Lawrence Hall, David Smith, Neal Weiner

Theories where the Standard Model fields reside on a 3-brane, with a low fundamental cut-off and extra dimensions, provide alternative solutions to the gauge hierarchy problem. However, generating flavor at the TeV scale while avoiding flavor-changing difficulties appears prohibitively difficult at first sight. We argue to the contrary that this picture allo

Randy Lewis, R. M. Woloshyn

The masses of S- and P-wave heavy-light mesons are computed in quenched QCD using a classically and tadpole-improved action on anisotropic lattices. Of particular interest are the splittings among P-wave states, which have not yet been resolved experimentally; even the ordering of these states continues to be discussed in the literature. The present work lea

Sergio Caracciolo, Andrea Montanari, Andrea Pelissetto

The operator product expansion is used to compute the matrix elements of composite renormalized operators on the lattice. We study the product of two fundamental fields in the two-dimensional sigma-model and discuss the possible sources of systematic errors. The key problem turns out to be the violation of asymptotic scaling.

K. Yamagishi, S. Kitahara, S. Ito, T. Tsunemi

Three topics concerning infrared effective lattice QCD are discussed. (1)Perfect lattice action of infrared SU(3) QCD and perfect operators for the static potential are analytically given when we assume two-point monopole interactions alone. The assumption seems to be justified from numerical analyses of pure SU(3) QCD in maximally abelian gauge. (2)Gauge in

S. Fujimoto, S. Kato, M. Murata, T. Suzuki

We study the perfect monopole action as an infrared effective theory of SU(2) QCD. It is transformed exactly into a lattice string model. Since the monopole interactions are weak in the infrared SU(2) QCD, the string interactions become strong. The strong coupling expansion of string model shows the quantum fluctuation is small. The classical string tension

Shouji Fujimoto, Seikou Kato, Tsuneo Suzuki

We found a quantum perfect lattice action in the 4-dimensional monopole current theory which is known as an effective theory in the infrared region of QCD. The perfect monopole action is transformed exactly into a lattice action of a string model. When the monopole interactions are weak as in the case of infrared SU(2) QCD, the string interactions are strong

Matthew Wingate

Due to the attractive features that domain wall fermions possess with respect to chiral symmetry, we continue our investigation of the light quark masses with this discretization. Achieving reliable results, especially for $(m_u + m_d)/2$, requires strict control of systematic uncertainties. Our present results were obtained on a quenched $β=6.0$ lattice wit

UKQCD Collaboration, C. M. Maynard

We present results of a lattice study of the form factors in the decay B-> pi l nu. We attempt to disentangle the the dependence of the form factors on the light quark masses and the momentum transfer. Using models of the q^2 dependence we calculate the total decay rate, and compare to the experimental measure to extract Vub. This study was performed in the

F. V. Gubarev, E. -M. Ilgenfritz, M. I. Polikarpov, T. Suzuki

Numerical data for the SU(2) confining string in the maximal abelian projection are analysed. The distribution of the electric flux and monopole currents are perfectly described by the classical equations of motion for the dual Abelian Higgs model. The mass of the vector boson is equal to the mass of the monopole (Higgs particle) within numerical errors. The

Joyce Garden, Marco Guagnelli, Jochen Heitger, Rainer Sommer

We review recent work by the ALPHA and UKQCD Collaborations where masses and matrix elements were computed in lattice QCD using Schrödinger functional boundary conditions and where the strange quark mass was determined in the quenched approximation. We emphasize the general concepts and our strategy for the computation of quark masses.

The NA48 Collaboration, V. Fanti

The NA48 experiment at CERN has performed a new measurement of direct CP violation, based on data taken in 1997 by simultaneously collecting K_L and K_S decays into pi0pi0 and pi+pi-. The result for the CP violating parameter Re(epsilon&#39;/epsilon) is (18.5 +/- 4.5(stat)} +/- 5.8 (syst))x10^{-4}.

H. G. Berns, R. J. Wilkes

The K2K (KEK E362) long-baseline neutrino oscillations experiment requires synchronization of clocks with ~100 nsec accuracy at the near and far detector sites (KEK and Super-Kamiokande, respectively), which are separated by 250 km. The Global Positioning System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low-resol

T. A. Larsson

The representation theory of non-centrally extended Lie algebras of Noether symmetries, including spacetime diffeomorphisms and reparametrizations of the observer&#39;s trajectory, has recently been developped. It naturally solves some long-standing problems in quantum gravity, e.g. the role of diffeomorphisms and the causal structure, but some new questions

J. Kierfeld, V. Vinokur

We develop a theory for dislocation-mediated structural transitions in the vortex lattice which allows for a unified description of phase transitions between the three phases, the elastic vortex glass, the amorphous vortex glass, and the vortex liquid, in terms of a free energy functional for the dislocation density. The origin of a critical endpoint of the

K. Kobayashi, T. Susaki, A. Fujimori, T. Tonogai

We have performed a photoemission study of Ti$_{4}$O$_{7}$ around its two transition temperatures so as to cover the metallic, high-temperature insulating (bipolaron-liquid), and low-temperature insulating (bipolaron-crystal) phases. While the spectra of the low-temperature insulating phase show a finite gap at the Fermi level, the spectra of the high-temper

Victor Barzykin, Ian Affleck

The single impurity Kondo model is often used to describe metals with dilute concentrations (n_i) of magnetic impurities. Here we examine how dilute the impurities must be for this to be valid by developing a virial expansion in impurity density. The O(n_i^2) term is determined from results on the 2-impurity Kondo problem by averaging over the RKKY coupling.

Ramandeep S. Johal

The purpose of this note is to argue that degree of nonextensivity as given by Tsallis distribution obtained from maximum entropy principle has a different origin than nonextensivity inferred from pseudo-additive property of Tsallis entropy.

P. Chandra, L. B. Ioffe

The demand for high-density data storage with ultrafast accessibility motivates the search for new memory implementations. Ideally such storage devices should be robust to input error and to unreliability of individual elements; furthermore information should be addressed by its content rather than by its location. Here we present a concept for an associativ