January 1998 arXiv papers

B. Melic, B. Nizic, K. Passek

We present the results of a complete leading-twist next-to-leading order (NLO) QCD analysis of the spacelike pion electromagnetic form factor at large momentum transfer Q. We have studied their dependence on the form of the pion distribution amplitude. For a given distribution amplitude, we have examined the sensitivity of the predictions to the choice of th

A. Lenz, U. Nierste, G. Ostermaier

We have calculated inclusive direct CP-asymmetries for charmless B^{+/-} -decays. After summing large logarithms to all orders the CP-asymmetries in Delta S=0 and Delta S=1 decays are found as a_{CP} (Delta S=0) = (2.0 +1.2/-1.0)% and a_{CP} (Delta S=1) = ( -1.0 +/- 0.5)%. These results are much larger than previous estimates based on a work without summatio

J. Maharana, E. Onofri, G. Veneziano

We analyse numerically the onset of pre-big bang inflation in an inhomogeneous, spherically symmetric Universe. Adding a small dilatonic perturbation to a trivial (Milne) background, we find that suitable regions of space undergo dilaton-driven inflation and quickly become spatially flat ($\Omega \to 1$). Numerical calculations are pushed close enough to the

M. Jimbo, H. Konno, S. Odake, J. Shiraishi

We investigate the structure of the elliptic algebra U_{q,p}(^sl_2) introduced earlier by one of the authors. Our construction is based on a new set of generating series in the quantum affine algebra U_q(^sl_2), which are elliptic analogs of the Drinfeld currents. They enable us to identify U_{q,p}(^sl_2) with the tensor product of U_q(^sl_2) and a Heisenber

A. A. Koulakov, A. I. Larkin

In the superclean case the spectrum of vortex core excitations in the presence of disorder is not random but consists of two series of equally-spaced levels. The I-V characteristics of such superconductors displays many interesting phenomena. A series of resonances is predicted at frequencies commensurate with the spacing of the vortex excitations. These res

Csaba Csaki, Martin Schmaltz, Witold Skiba, John Terning

We present brane constructions in Type IIA string theory for N=1 supersymmetric SO and Sp gauge theories with tensor representations using an orientifold 6-plane. One limit of these set-ups corresponds to N=2 theories previously constructed by Landsteiner and Lopez, while a different limit yields N=1 SO or Sp theories with a massless tensor and no superpoten

Unal Goktas, Willy Hereman

A straightforward algorithm for the symbolic computation of higher-order symmetries of nonlinear evolution equations and lattice equations is presented. The scaling properties of the evolution or lattice equations are used to determine the polynomial form of the higher-order symmetries. The coefficients of the symmetry can be found by solving a linear system

Yan Jie, Liu Quan-Hui, Liu Ji-Xing, Ou-Yang Zhong-Can

By means of Surface Evolver (Exp. Math,1,141 1992), a software package of brute-force energy minimization over a triangulated surface developed by the geometry center of University of Minnesota, we have numerically searched the non-axisymmetric shapes under the Helfrich spontaneous curvature (SC) energy model. We show for the first time there are abundant me

J. Wambach, R. Rapp

An overview is given of chiral symmetry restoration at finite temperature and baryochemical potential. Within hadronic models of the vector correlator its implications for low-mass dilepton spectra in ultrarelativistic heavy-ion collisions are discussed.

John Kalliongis, Darryl McCullough

Around 1960, R. Palais and J. Cerf proved a fundamental result relating spaces of diffeomorphisms and imbeddings of manifolds: If V is a submanifold of M, then the map from Diff(M) to Imb(V,M) that takes f to its restriction to V is locally trivial. We extend this and related results into the context of fibered manifolds, and fiber-preserving diffeomorphisms

Anatol N. Kirillov

We construct a certain solution to the Witten--Dijkgraf--Verlinde--Verlinde equation related to the small quantum cohomology ring of flag variety, and study the t-deformation of quantum Schubert polynomials corresponding to this solution.

Boguslaw Broda, Malgorzata Bakalarska

A dual description of 3-dimensional topological Seiberg-Witten theory in terms of the Alexander invariant on manifolds obtained via surgery on a knot is proposed. The description directly follows from a low-energy analysis of the corresponding SUSY theory, in full analogy to the 4-dimensional case.

Clifford V. Johnson

This presentation is intended to give a flavour of the physics to be studied and discovered by exploiting the interface between string theory, M-theory and field theory provided by the dynamics of extended objects called `branes', and their relationships under string duality. It is quite non-technical, with very few equations but many pictorial illustrat

Harry J. Lipkin

New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in $B^\pm$ decays to final states containing neutral flavor-mixed mesons like $ω$, $ϕ$, $η$ and $η'$. The most general strong-interaction diagrams containing arbitrary numbers of quarks and gluons are included w

Jun-ichi Kamoshita

We examine whether parameters related to Higgs sector of the minimal supersymmetric standard model can be determined by detailed study of production cross section and decay branching ratios of the Higgs boson. Assuming that only the light Higgs boson is observed at a future $e^+e^-$ linear collider with $\sqrt{s}=300\sim500$GeV, we show that values of $m_{su

The OPAL Collaboration, K. Ackerstaff et al

This paper presents updated measurements of the lifetimes of the B^0_s meson and the Λ_b baryon using 4.4 million hadronic Z^0 decays recorded by the OPAL detector at LEP from 1990 to 1995. A sample of B^0_s decays is obtained using D_s^- \ell^+ combinations, where the D_s^- is fully reconstructed in the ϕπ^-, K^*0 K^- and K^- K^0_S decay channels and partia

Dietrich Wegener

b-Quark Physics at DORIS

P. Bizoń, T. Chmaj

In recent numerical simulations of spherically symmetric gravitational collapse a new type of critical behaviour, dominated by a sphaleron solution, has been found. In contrast to the previously studied models, in this case there is a finite gap in the spectrum of black-hole masses which is reminiscent of a first order phase transition. We briefly summarize

Stephen D. H. Hsu

We investigate the ratio of gravitational binding energy to rest mass in general relativity. For N pointlike masses, an upper bound on the magnitude of this ratio can be derived using the second law of black hole dynamics. Only as N approaches infinity can it approach one. A configuration that saturates the $N = \infty$ bound is a thin spherical shell as its

R. Resta

The position operator (defined within Schroedinger representation as usual) becomes meaningless when the usual Born-von Karman periodic boundary conditions are adopted: this fact is at the root of the polarization problem. I show how to define the position expectation value by means of rather peculiar many-body (multiplicative) operator acting on the wavefun

M. J. P. Gingras, Erik S. Sorensen

uch experimental and theoretical efforts have been devoted in the past twenty years to search for a genuine thermodynamic reentrant phase transition from a ferromagnetic to either a paramagnetic or spin glass phase in disordered ferromagnets. So far, no real system or theoretical model of a short-range spin glass system has been shown to convincingly display

Tom Chou

A nonlinear kinetic exclusion model is used to study osmosis and pressure driven flows through nearly single file pores such as antibiotic channels, aquaporins, zeolites and nanotubules. Two possible maxima in the steady state flux as a function of pore-solvent affinity are found. For small driving forces, the linear macroscopic osmotic and hydraulic permeab

Han-Tzong Su, Yaw-Hwang Chen, Rue-Ron Hsu

This brief report presents a master-slave scheme to demonstrate how control chaos in the Braiman and Goldhirsch method for the one- dimensional map system. The scheme also naturally explain why the anomalous response arises in a periodically perturbed, unimodal map system.

K. D. Gordon, G. C. Clayton

The recent discovery that the UV dust extinction in starburst galaxies is similar to that found in the Small Magellanic Cloud (SMC) motivated us to re-investigate the ultraviolet (UV) extinction found in the SMC. We have been able to improve significantly on previous studies by carefully choosing pairs of well matched reddened and unreddened stars. In additi

Rennan Barkana

Because of their simplicity, axisymmetric mass distributions are often used to model gravitational lenses. Since galaxies are usually observed to have elliptical light distributions, mass distributions with elliptical density contours offer more general and realistic lens models. They are difficult to use, however, since previous studies have shown that the

J. H. Beall, W. Bednarek

We consider, herein, a model for gamma-ray production in blazars in which a relativistic, highly-collimated electron-proton beam interacts with a dense, compact cloud as the jet propagates through the broad and perhaps narrow line regions (BLR and NLR) of active galactic nuclei (AGN). During the propagation of the beam through the cloud, the process of excit

P. McCormick, J. Frank

The orbital evolution of cataclysmic variables in which the companion is illuminated by a fraction of the accretion luminosity consists of irradiation-driven limit cycles on thermal timescales, superimposed on a secular evolution toward shorter periods due to systemic angular momentum losses. We show that positive orbital period derivatives during bright pha

Yiping Wang, Peter L. Biermann

There is an interesting correlation between the central objects and their host galaxies in recent high resolution HST photometry of early type galaxies and Near-IR images of nearby quasar hosts. It has been shown that a) the hosts of these very luminous quasars are likely to be early type galaxies and that b) the mass ratio of central black holes (BHs) and t

J. Acacio de Barros, N. Pinto-Neto, M. A. Sagioro-Leal

This paper has been withdrawn due to crucial erros in equations (24)--(31).

Leonard Parker, Alpan Raval

We show that there exists a choice of scalar field modes, such that the evolution of the quantum field in the zero-mass and large-mass limits is consistent with the Einstein equations for the background geometry. This choice of modes is also consistent with zero production of these particles and thus corresponds to a preferred vacuum state preserved by the e

Kimberly C. B. New, Keith Watt, Charles W. Misner, Joan M. Centrella

The 3-level leapfrog time integration algorithm is an attractive choice for numerical relativity simulations since it is time-symmetric and avoids non-physical damping. In Newtonian problems without velocity dependent forces, this method enjoys the advantage of long term stability. However, for more general differential equations, whether ordinary or partial

P. Claus, R. Kallosh, J. Kumar, P. K. Townsend

The bosonic actions for M2, D3 and M5 branes in their own d-dimensional near-horizon background are given in a manifestly SO(p+1,2) x SO(d-p-1) invariant form (p=2,3,5). These symmetries result from a breakdown of ISO(d,2) (with d=10 for D3 and d=11 for M2 and M5) symmetry by the Wess-Zumino term and constraints. The new brane actions, reduce after gauge-fix

M. Ozana, A. L. Shelankov

For a charged particle in a homogeneous magnetic field, we construct stationary squeezed states which are eigenfunctions of the Hamiltonian and the non-Hermitian operator $\hat{X}_Φ = \hat{X} \cos Φ+ \hat{Y} \sin Φ$, $\hat{X}$ and $\hat{Y}$ being the coordinates of the Larmor circle center and $Φ$ is a complex parameter. In the family of the squeezed states,

Junseong Heo, Tanmay Vachaspati

We construct Z_3 vortex solutions in a model in which SU(3) is spontaneously broken to Z_3. The model is truncated to one in which there are only two dimensionless free parameters and the interaction of vortices within this restricted set of models is studied numerically. We find that there is a curve in the two dimensional space of parameters for which the

D. Bazeia, F. Moraes

Generalizations of the Korteweg-de Vries equation are considered, and some explicit solutions are presented. There are situations where solutions engender the interesting property of being chiral, that is, of having velocity determined in terms of the parameters that define the generalized equation, with a definite sign.

B. Datta, A. V. Thampan, I. Bombaci

For four newly suggested microscopic equations of state of neutron star matter, we construct equilibrium sequences of rapidly rotating neutron stars in general relativity. The sequences are the normal and supramassive evolutionary sequences of constant rest mass. We find that for these equations of state the maximum (gravitational) mass rotating models occur

D. Duerr, S. Goldstein, K. Muench-Berndl, N. Zanghi

We define a class of Lorentz invariant Bohmian quantum models for N entangled but noninteracting Dirac particles. Lorentz invariance is achieved for these models through the incorporation of an additional dynamical space-time structure provided by a foliation of space-time. These models can be regarded as the extension of Bohm's model for N Dirac particl

R. Brandenberger, A. Riotto

A generic prediction of models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge interactions is the existence of superconducting cosmic strings which carry baryon number. In this paper we propose a novel mechanism for the generation of the baryon asymmetry which takes

Akira Takamura, Ken'ichi Takano

We algebraically construct the Fock space of the Sutherland model in terms of the eigenstates of the pseudomomenta as basis vectors. For this purpose, we derive the raising and lowering operators which increase and decrease eigenvalues of pseudomomenta. The operators exchanging eigenvalues of two pseudomomenta have been known. All the eigenstates are systema

P. Jizba

With non-equilibrium applications in mind we present in this paper a self-contained calculation of the hydrostatic pressure of the O(N)λϕ^4 theory at finite temperature. By combining the Keldysh-Schwinger closed-time path formalism with thermal Dyson-Schwinger equations we compute in the large N limit the hydrostatic pressure in a fully resumed form. We also

S. Krivonos, A. Pashnev, Z. Popowicz

We present the Lax operator for the N=3 KdV hierarchy and consider its extensions. We also construct a new infinite family of N=2 supersymmetric hierarchies by exhibiting the corresponding super Lax operators. The new realization of N=4 supersymmetry on the two general N=2 superfields, bosonic spin 1 and fermionic spin 1/2, is discussed.

N. Linden, S. Popescu, A. Sudbery

As far as entanglement is concerned, two density matrices of $n$ particles are equivalent if they are on the same orbit of the group of local unitary transformations, $U(d_1)\times...\times U(d_n)$ (where the Hilbert space of particle $r$ has dimension $d_r$). We show that for $n$ greater than or equal to two, the number of independent parameters needed to s

Marc-Thierry Jaekel, Serge Reynaud

We discuss a limit for sensitivity of length measurements which is due to the effect of vacuum fluctuations of gravitational field. This limit is associated with irreducible quantum fluctuations of geodesic distances and it is characterized by a noise spectrum with an order of magnitude mainly determined by Planck length. The gravitational vacuum fluctuation

Marc-Thierry Jaekel, Serge Reynaud

A mirror in vacuum is coupled to fluctuating quantum fields. As a result, its energy-momentum and mass fluctuate. We compute the correlation spectra of force and mass fluctuations for a mirror at rest in vacuum (of a scalar field in a two-dimensional space-time). The obtained expressions agree with a mass correction equal to a vacuum energy stored by the mir

Marc-Thierry Jaekel, Serge Reynaud

Different quantum Langevin equations obtained by coupling a particle to a field are examined. Instabilities or violations of causality affect the motion of a point charge linearly coupled to the electromagnetic field. In contrast, coupling a scatterer with a reflection cut-off to radiation pressure leads to stable and causal motions. The radiative reaction f

Marc-Thierry Jaekel, Astrid Lambrecht, Serge Reynaud

The existence of vacuum fluctuations leads to reconsider the question of relativity of motion. The present article is devoted to this aim with a main line which can be formulated as follows: ``The principle of relativity of motion is directly related to symmetries of quantum vacuum''. Keeping close to this statement, we discuss the controversial rela

P. Haridas, I. A. Pless, G. Van Buren, J. Tomasi

The E864 experiment at BNL requires a beam counter and multiplicity detector system that can perform at an incident beam rate of 10^7 Au ions per second. We have developed and tested a 150 micrometer thick quartz Cherenkov beam counter and a scintillator based multiplicity-trigger counter during the first run of this experiment in 1994. We obtained a time re

M. Reiter, A. Dumitru, J. Brachmann, J. A. Maruhn

Entropy production in the initial compression stage of relativistic heavy-ion collisions from AGS to SPS energies is calculated within a three-fluid hydrodynamical model. The entropy per participating net baryon is found to increase smoothly and does not exhibit a jump or a plateau as in the 1-dimensional one-fluid shock model. Therefore, the excess of pions

B. -J. Schaefer, H. J. Pirner

Nonperturbative Flow Equations within an effective constituent quark model for two quark flavors with Heat-Kernel methods are studied.

Martin Bordemann, Hartmann Roemer, Stefan Waldmann

In the framework of deformation quantization we define formal KMS states on the deformed algebra of power series of functions with compact support in phase space as C[[λ]]-linear functionals obeying a formal variant of the usual KMS condition known in the theory of C^*-algebras. We show that for each temperature KMS states always exist and are up to a normal

Francisco J. Plaza Martín

This paper aims at generalizing some geometric properties of Grassmannians of finite dimensional vector spaces to the case of Grassmannnians of infinite dimensional ones, in particular for that of $k((z))$. It is shown that the Determinant Line Bundle generates its Picard Group and that the Plücker equations define it as closed subscheme of a infinite projec

Masaaki Umehara, Kotaro Yamada

A necessary and sufficient condition for the existence and uniqueness of a conformal metric on 2-sphere of constant curvature 1 and with three conical singularities of prescribed order is given.

Dmitri Zaitsev

We prove that a germ of a holomorphic map $f$ between $C^n$ and $C^{n'}$ sending one real-algebraic submanifold $M\subset C^n$ into another $M'\subset C^{n'}$ is algebraic provided $M'$ contains no complex-analytic discs and $M$ is generic and minimal. We also propose an algorithm for finding complex-analytic discs in a real submanifold.

Matthias R. Gaberdiel, Tamas Hauer, Barton Zwiebach

It is confirmed that geodesic string junctions are necessary to describe the gauge vectors of symmetry groups that arise in the context of IIB superstrings compactified in the presence of nonlocal 7-branes. By examining the moduli space of 7-brane backgrounds for which the dilaton and axion fields are constant, we are able to describe explicitly and geometri

C. S. Chu, P. S. Howe, E. Sezgin

The covariant field equations of ten-dimensional super D-branes are obtained by considering fundamental strings whose ends lie in the superworldsurface of the D-brane. By considering in a similar fashion Dp-branes ending on D(p+2)-branes we derive equations describing D-branes with dual potentials, as well as the vector potentials.

Kazunari Shima

A unified description of spacetime and matter at the Planck scale is proposed by using the irreducible representation of N=10 extended Super-Poincaré algebra, where all matters and all forces except the graviton are the supersymmetric composites made of the fundamental objects with spin 1/2, superon quintet. All the local gauge interactions in GUTs are inves

D. Maxera

A modified algorithm for the construction of nonlinear realizations (sigma models) is applied to the general covariance group. Our method features finite dimensionality of the coset manifold by letting the vacuum stability group be infinite. No decomposition of the symmetry group to its finite-dimensional subgroups is required. The expected result, i.e. Eins

Gerhard Buchalla, Gino Isidori

We reconsider the calculation of ${\cal O}(Λ^2_{QCD}/m^2_b)$ nonperturbative corrections to $\bar B\to X_sl^+l^-$ decay. Our analysis confirms the results of Ali et al. for the dilepton invariant mass spectrum, which were in disagreement with an earlier publication, and for the lepton forward-backward asymmetry. We also give expressions for the ${\cal O}(Λ^2

Pran Nath, R. Arnowitt

Future sattelite, balloon and ground based experiments will give precision determinations of the basic cosmological parameters and hence determine the amount of cold dark matter accurately. We consider here two cosmological models, the nuCDM model and the LambdaCDM model, and examine within the framework of supergravity grand unification the effect this will

D. Boyanovsky, D. Cormier, H. J. de Vega, R. Holman

The energy and time scales during the inflationary stage of the universe calls for an out of equilibrium quantum field treatment. Moreover, the high energy densities involved make necessary the use of non-perturbative approaches as large N and Hartree methods. We start these lectures by introducing such non-perturbative out of equilibrium methods in cosmolog

V. Barger

The phenomenology of a low-energy supersymmetry at hadron colliders is discussed with consideration of the minimal supergravity model, with a large top quark Yukawa coupling at the grand unification mass scale, and gauge mediated symmetry breaking models. Possible supersymmetry interpretations of some unexplained events are mentioned.

M. Bastero-Gil, S. F. King

In this talk we discuss a model of inflation based on a simple variant of the NMSSM, called $ϕ$NMSSM \cite{phiNMSSM}, where the additional singlet $ϕ$ plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the $ϕ$NMSSM solves the $μ$ problem of the MSSM via the VEV of a gauge singlet $N$, but unlike the NMSSM doe

Xiaofeng Guo

In terms of multiple scattering picture, I compute the nuclear dependence in Drell-Yan transverse momentum distribution, $dσ/ dQ^2 dq_T^2$, in hadron-nucleus collisions. I present the results for large $q_T$ region and discuss the possible suppression in small $q_T$ region.

David Wright

We consider the bounds imposed by naturalness on the masses of superpartners for arbitrary points in nonminimal supersymmetric extensions of the standard model and for arbitrary messenger scales. This constitutes a significant generalization of previous work along these lines. We discuss appropriate measures of naturalness and the status of nonminimal supers

Mohammad R. Ahmady, Victor Elias, Emi Kou

We investigate the momentum dependence of the g*-g-eta' vertex form factor in the presence of the nonperturbative QCD vacuum condensate. The behaviour of this form factor is crucial for, among other things, some proposed mechanisms devised to explain the large branching ratio for fast eta' production in charmless B decays observed by CLEO. We show th

The OPAL Collaboration, K. Ackerstaff et al

The branching ratios of the τ^- -> h^- ν_τ, τ^- -> h^- π^0 ν_τ, τ^- -> h^- >=2 π^0 ν_τdecays have been measured using the 1991-1995 data recorded with the OPAL detector at LEP. These branching ratios are measured simultaneously using three selection criteria and are found to be BR(τ^- -> h^- ν_τ) = (11.98 +/- 0.13 +/- 0.16)% BR(τ^- -> h^- π^0 ν_τ) = (25.89 +

F. Dahia, C. Romero

We consider the problem of calculating the Gaussian curvature of a conical 2-dimensional space by using concepts and techniques of distribution theory. We apply the results obtained to calculate the Riemannian curvature of the 4-dimensional conical space-time. We show that the method can be extended for calculating the curvature of a special class of more ge

Jean-Philippe Uzan

Starting from a microscopic approach, we develop a covariant formalism to describe a set of interacting gases. For that purpose, we model the collision term entering the Boltzmann equation for a class of interactions and then integrate this equation to obtain an effective macroscopic description. This formalism will be useful to study the cosmic microwave ba

Per Jögi, Didier Sornette

We uncover a nontrivial signature of the hierarchical structure of quasi-degenerate random directed polymers (RDPs) at zero temperature in 1+1 dimensional lattices. Using a cylindrical geometry with circumference $8 \leq W \leq 512$, we study the differences in configurations taken by RDPs forced to pass through points displaced successively by one unit latt

M. Fleck, A. I. Lichtenstein, A. M. Oles, L. Hedin

We have generalized the dynamical mean-field theory to study the doping dependence of the crossover from antiferromagnetic to short-range order modelled by an incommensurate spin density wave in the Hubbard model. The local selfenergy which includes spin fluctuations gives quasiparticle weights and spectral properties in good agreement with quantum Monte Car

A. G. Green

The distinguishing feature of the quantum Hall ferromagnet is the identity between the electrical and topological charge densities of a spin distortion. In addition to the wealth of physics associated with Skyrmionic excitations of the quantum Hall ferromagnet, this identification permits a rather curious coupling of spinwaves to the disorder potential. A wa

A. Garcia-Martin, J. A. Torres, J. J. Saenz, M. Nieto-Vesperinas

Exact calculations of the transmittance of surface corrugated optical waveguides are presented. The elastic scattering of diffuse light or other electromagnetic waves from a rough surface induces a diffusive transport along the waveguide axis. As the length of the corrugated part of the waveguide increases, a transition from the diffusive to the localized re

P. Santa-Clara, D. Sornette

This paper offers a new class of models of the term structure of interest rates. We allow each instantaneous forward rate to be driven by a different stochastic shock, constrained in such a way as to keep the forward rate curve continuous. We term the process followed by the shocks to the forward curve ``stochastic strings'', and construct them as th

M. Pleimling, W. Selke

Using Monte Carlo techniques, the critical behaviour at edges and corners of the three-dimensional Ising model is studied. In particular, the critical exponent $β_2$ of the local magnetization at edges formed by two intersecting free surfaces is estimated to be, as a function of the opening angle $θ$, $0.96 \pm 0.02$ for $θ= 135^o$, $1.28 \pm 0.04$ for $90^o

Gwang-Hee Kim

At finite temperature we study the quantum tunneling of magnetization for a small ferromagnetic particle with the biaxial symmetry placed in a magnetic field at an arbitrary angle. We present numerical WKB exponent below the crossover temperature in which the quantum tunneling is affected by the thermal activation, and the approximate form of the WKB exponen

S. Conti, G. Vignale

We develop a bosonization scheme for the collective dynamics of a spinless two-dimensional electron gas (2DEG) in the lowest Landau level. The system is treated as a continuous elastic medium, and quantum commutation relations are imposed between orthogonal components of the elastic displacement field. This theory provides a unified description of bulk and e

A. Putrino, G. B. Bachelet

Curvilinear coordinates, first introduced by F. Gygi for valence-only electronic systems within the local-density functional theory, can be used to describe both core and valence electrons in electronic-structure calculations. A simple and quite general coordinate transformation results in a large, yet affordable plane-wave energy cutoff for full-core system

Jon A. Holtzman, Alan M. Watson, William A. Baum, Carl J. Grillmair

We present deep photometry obtained with the Hubble Space Telescope (HST) in a field in Baade's Window in the Galactic bulge. We derive a luminosity function down to I ~ 24.3, or V ~ 27.5, corresponding to M ~ 0.3 Msun. The luminosity function from the turnoff down to this level appears remarkably similar to that observed in the solar neighborhood. We de

M. Altmann, W. Hillebrandt, H. -T. Janka, G. Raffelt

Collection of "Extended Abstracts" of talks presented at the SFB-375 workshop NEUTRINO ASTROPHYSICS, Ringberg Castle, Tegernsee, Germany, 20-24 Oct. 1997. Topics include Solar Neutrinos, Supernovae, Gamma-Ray Bursts, High-Energy Neutrinos (atmospheric, astrophysical), Cosmology, and Future Prospects. The focus is on astrophysical and experimental/obs

F. Combes, D. Pfenniger

Over the last two decades, realistic studies have often concluded that the first bound objects to form can be very small, much smaller than a solar mass. After recombination, the Jeans mass drops rapidly to the order of a Giant Molecular Cloud (GMC) mass ($\sim 10^5$ M$_\odot$), and the H$_2$ cooling can make the collapse quasi-isothermal; this leads to recu

E. Brocato, V. Castellani, F. L. Villante

We discuss theoretical predictions concerning the evolution of globular cluster Pop.II stars vis-a-vis current estimates of standard errors in the determination of nuclear burning rates. Numerical evaluations are given for the dependence of TO and HB luminosity from the rate of the relevant nuclear reactions. We conclude that evolutionary predictions appear

A. M. Read, T. J. Ponman

We present here the first study of the X-ray properties of an evolutionary sample of merging galaxies. Both ROSAT PSPC and HRI data are presented for a sample of eight interacting galaxy systems, each believed to involve a similar encounter between two spiral discs of approximately equal size. The mergers span a large range in age, from completely detached t

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

The best studied gravitational lens is the Twin QSO Q0957+561, and as a result of recent advances in observations and modelling, a ten percent measurement of the Hubble constant is attainable. We discuss in detail this system and review the perspectives in a near future.

A. V. Gurevich, K. P. Zybin, V. A. Sirota

It has been revealed using microlensing that a considerable part, possibly more than half, of the dark matter in the halo of our Galaxy consists of objects with a mass spectrum ranging from 0.05 to 0.8 of the solar mass. What is the nature of these objects? There exist two hypotheses. According to one, these are Jupiter type planets or small stars (brown and

K. S. Capelle, J. W. Cronin, G. Parente, E. Zas

We show that the Auger Air Shower Array has the potential to detect neutrinos of energies in the $10^{19}~$eV range through horizontal air showers. Assuming some simple conservative trigger requirements we obtain the acceptance for horizontal air showers as induced by high energy neutrinos by two alternative methods and we then give the expected event rates

S. von Linden, K. Otmianowska-Mazur, H. Lesch, G. Skupniewicz

A fully three-dimensional computation of induction processes in a disk is performed to investigate the evolution of a large-scale magnetic field in gas-rich barred and spiral galaxies in the presence of field diffusion. As input parameters we use time dependent velocity fields obtained from self-consistent 3D N-body calculations of galactic dynamics. Our pre

A. Aragon-Salamanca, C. M. Baugh, G. Kauffmann

The K-band Hubble diagram for a sample of brightest cluster galaxies (BCGs) in the redshift range 0<z<1 shows a very small scatter (0.3 magnitudes r.m.s). The BCGs exhibit very little luminosity evolution in this redshift range: if q_0=0.0 we detect no luminosity evolution; for q_0=0.5 we measure a small negative evolution. If the mass in stars of these gala

K. Agashe, M. Graesser

The supersymmetric contributions to the Flavor Changing Neutral Current processes may be suppressed by decoupling the scalars of the first and second generations. It is known, however, that the heavy scalars drive the stop mass squareds negative through the two-loop Renormalization Group evolution. This tension is studied in detail. Two new items are include

John Ellis, Toby Falk, Gerardo Ganis, Keith A. Olive

We analyze the LEP constraints from searches for charginos $χ^{\pm}$ and neutralinos $χ_i$, taking into account radiative corrections to the relations between their masses and the underlying Higgs-mixing and gaugino-mass parameters $μ, m_{1/2}$ and the trilinear mass parameter $A_t$. Whilst radiative corrections do not alter the excluded domain in $m_{χ^{\pm

J. Huston, S. Kuhlmann, H. L. Lai, F. Olness

The uncertainty in the calculation of many important new processes at the Tevatron and LHC is dominated by that concerning the gluon distribution function. We investigate the uncertainty in the gluon distribution of the proton by systematically varying the gluon parameters in the global QCD analysis of parton distributions. The results depend critically on t

S. Boffi, F. Capuzzi, P. Demetriou, M. Radici

The charge-current density and two-photon operators consistent with a single-particle semi-relativistic Hamiltonian are derived within a suitable functional derivative formalism which preserves gauge invariance. An application to electron scattering is presented and results are compared with a fully relativistic case and the non-relativistic cases corrected

Alessandra Buonanno, Thibault Damour

We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After verifying the (on average) conservative nature of the time-symmetric self-interactions, we concentrate on the finite radiation damping force associated with the half-retarded minus half-advanced ``reactive&#39;&#39; fields. We revisit a

Pavel Etingof, Alexander Varchenko

For any simple Lie algebra g and any complex number q which is not zero or a nontrivial root of unity, we construct a dynamical quantum group (Hopf algebroid), whose representation theory is essentially the same as the representation theory of the quantum group U_q(g). This dynamical quantum group is obtained from the fusion and exchange relations between in

Andreas E. Klinkmueller, G. Haeffler, D. Hanstorp, I. Yu. Kiyan

The photodetachment cross section of He^- has been measured in the photon energy range 2.9 eV to 3.3 eV in order to investigate doubly excited states. Measurements were made channel specific by selectively detecting the residual He atoms left in a particular excited state following detachment. Three Feshbach resonances were found in the He(1s2p ^3P)+e^-(epsi

Robert Gebarowski, Petr Seba, Karol Zyczkowski, Jakub Zakrzewski

Quantum scattering is studied in a system consisting of randomly distributed point scatterers in the strip. The model is continuous yet exactly solvable. Varying the number of scatterers (the sample length) we investigate a transition between the ballistic and the localized regimes. By considering the cylinder geometry and introducing the magnetic flux we ar

R. Aldrovandi, A. L. Barbosa, L. C. B. Crispino, J. G. Pereira

Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein&#39;s equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are

Christopher Balzereit

We present a calculation of the renormalized HQET Lagrangian at order O(1/m_Q^3) in the one particle sector. The anomalous dimensions of local operators and time ordered products of dimension 7 contributing at this order are calculated in the one loop approximation. We show that a careful treatment of the time ordered products is necessary to arrive at a gau

J. Caro, C. Garcia-Recio, J. Nieves

We fit the $^1 S_0 ΛΛ$ interaction in the nuclear medium to the masses of the experimentally known double-$Λ$ hypernuclei: $^{\phantom{6}6}_{ΛΛ}$He, $^{10}_{ΛΛ}$Be and $^{13}_{ΛΛ}$B. We derive this effective interaction from OBE Jülich $ΛΛ$-type potentials and using both Hartree-Fock and variational approaches. We find that the inclusion of $ΛΛ$ correlations

N. C. J. Schoonderwoerd, B. L. G. Bakker

Light-front dynamics can only become a viable alternative to the covariant approach if doubts about its covariance can be taken away. As a minimal requirement we take that the physical quantities calculated with light-front perturbation theory are the same as those obtained using covariant perturbation theory. If this situation occurs, we use the word equiva

K. Tsushima, A. Sibirtsev, A. W. Thomas, G. Q. Li

The energy dependence of the total kaon production cross sections in baryon baryon ($N$ and $Δ$) collisions are studied in the resonance model, which is a relativistic, tree-level treatment. This study is the first attempt to complete a systematic, consistent investigation of the elementary kaon production reactions for both the pion baryon and baryon baryon