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February 1999 arXiv papers — page 12

Showing 1,1011,200 of 1,931 papers

  1. Gary Gruenhage, J. Tatch Moore

    A space X is called an alpha-Toronto space if X is scattered of Cantor-Bendixson rank alpha and is homeomorphic to each of its subspaces of same rank. We answer a question of Steprans by constructing a countable alpha-Toronto space for each alpha<=omega. We also construct consistent examples of countable alpha-Toronto spaces for each alpha<omega_1.

  2. J. Zintl

    Compactifications of moduli spaces of (1,p)-polarized abelian surfaces with level structures of canonical type have been described in great detail by Hulek, Kahn and Weintraub. The aim of this paper is to determine some invariants of smooth models of these moduli spaces. In particular, a geometric description of their canonical divisors is given and their Ch

  3. Xufeng Liu

    The structure of the tensor product representation v_{λ_1}(x)\otimes V_{λ_2}(y) of U_q(\hat sl_2) is investigated at roots of unity. A polynomial identity is derived as an outcome. Also, new bases of v_{λ_1}(x)\otimes V_{λ_2}(y) are established under certain conditions.

  4. A. M. Fedotov, V. D. Mur, N. B. Narozhny, V. A. Belinskii

    It is shown using both conventional and algebraic approach to quantum field theory that it is impossible to perform quantization on Unruh modes in Minkowski spacetime. Such quantization implies setting boundary condition for the quantum field operator which changes topological properties and symmetry group of spacetime and leads to field theory in two discon

  5. Bayram Tekin

    Canonical quantization of three dimensional gravity in the first order formalism suggests that one should allow singular solutions. This paper addresses the importance of singular solutions in the path integral approach to quantum gravity. Using a simple ansatz for the dreibein and the spin connection in the de-Sitter and the anti-de-Sitter spaces we propose

  6. G. P. Pronko, Yu. G. Stroganov

    The full set of polynomial solutions of the nested Bethe Ansatz is constructed for the case of A_2 rational spin chain. The structure and properties of these associated solutions are more various then in the case of usual XXX (A_1) spin chain but their role is similar.

  7. F. T. Brandt, Ashok Das, J. Frenkel

    In this paper, we extend our earlier one loop analysis to two loops and give a simple diagrammatic description for the retarded Greens functions at finite temperature, in terms of forward scattering amplitudes of on-shell thermal particles. We present a simple discussion, which can be easily generalized to any field theory, of the temperature dependent parts

  8. Sze-Shiang Feng, Bin Wang

    The N=1 self-dual supergravity has SL(2,C) and the left-handed and right -handed local supersymmetries. These symmetries result in SU(2) charges as the angular-momentum and the supercharges. The model possesses also the invariance under the general translation transforms and this invariance leads to the energy-momentum. All the definitions are generally cova

  9. Jeong-Hyuck Park

    A new type of non-Abelian generalization of the Born-Infeld action is proposed, in which the spacetime indices and group indices are combined. The action is manifestly Lorentz and gauge invariant. In its power expansion, the lowest order term is the Yang-Mills action and the second term corresponds to the bosonic stringy correction to this action. Solutions

  10. Zurab Kakushadze

    Recently a TeV-scale Supersymmetric Standard Model (TSSM) was proposed in which the gauge coupling unification is as precise (at one loop) as in the MSSM, and occurs in the TeV range. Proton stability in the TSSM is due to an anomaly free Z_3 X Z_3 discrete gauge symmetry, which is also essential for successfully generating neutrino masses in the desirable r

  11. N. Ano

    The correspondence between the ground states of the BFSS matrix model and the type IIA string is investigated through the 11th direction. We derive the type IIA string from 11 dimensional supermembrane wrapped around the 11th direction of periodicity without a procedure of the double dimensional reduction, but by taking the large limit of radius R in the 11t

  12. V. Dzhunushaliev, D. Singleton

    Spherically and cylindrically symmetric solutions of SU(3) Yang-Mills theory are found, whose gauge potentials have confining properties. The spherically symmetric solutions give field distributions which have a spherical surface on which the gauge fields become infinite (which is similar to bag models of confinement), and the other solution has a potential

  13. James M. Cline

    The status of electroweak baryogenesis in the minimal supersymmetric standard model is reviewed. I discuss the strength of the phase transition, CP violation and transport at the bubble walls, and the possibility of a two stage transition involving charge and color breaking.

  14. S. J. Huber

    Singlet extensions of the Standard Model (SM) allow for a strongly first order electroweak phase transition, because of trilinear terms in the tree-level potential. We present a systematic procedure to study the parameter space of the Next-to-Minimal Supersymmetric SM (NMSSM). We find that this model is consistent with electroweak baryogenesis for a wide ran

  15. Pran Nath, Masahiro Yamaguchi

    Effects of Kaluza-Klein excitations associated with extra dimensions with large radius compactifications on the Fermi constant are explored. It is shown that the current precision determinations of the Fermi constant, of the fine structure constant, and of the W and Z mass put stringent constraints on the compactification radius. The analysis excludes one ex

  16. O. Schroeder, H. Reinhardt, H. Weigel

    We study the relevance of strange degrees of freedom for nucleon structure functions. For this purpose we employ the three flavor generalization of the collective quantization approach to the chiral soliton of the bosonized Nambu-Jona-Lasinio model. Contrary to many other soliton models the hadronic tensor is tractable in this model. By applying the Bjorken

  17. M. C. Gonzalez-Garcia

    We review the effects of new effective interactions on the Higgs boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge bosons leading to anomalous Higgs couplings as well as to anomalous gauge-boson self-interactions. Using a linearly realized

  18. L. G. Dakhno, V. A. Nikonov

    On the basis of the experimental data on diffractive processes in $πp$, $pp$ and $p \bar p$ collisions at intermediate, moderately high and high energies, we restore the scattering amplitude related to the $t$-channel exchange by vacuum quantum numbers by taking account of the diffractive $s$-channel rescatterings. At intermediate and moderately high energie

  19. D. -U. Jungnickel, C. Wetterich

    We review the formalism of the effective average action in quantum field theory which corresponds to a coarse grained free energy in statistical mechanics. The associated exact renormalization group equation and possible nonperturbative approximations for its solution are discussed. We describe in detail O(N)-symmetric scalar theories in two and three dimens

  20. S. Hino, S. Kumano

    We show in general that there are 108 structure functions in the proton-deuteron Drell-Yan processes. However, there exist only 22 finite ones after integrating the cross section over the virtual-photon transverse momentum \vec Q_T or after taking the limit Q_T->0. There are 11 new structure functions in comparison with the ones of the proton-proton reaction

  21. Walter D. Goldberger

    Physics beyond the Standard Model could be measured indirectly, through its effects on Standard Model observables. One place to look for such effects is in the semileptonic decays of B mesons. In order to constrain the possible role of new physics on semileptonic B decays, we present the most general low energy effective Lagrangian constructed from all dimen

  22. J. F. Gunion, B. Grzadkowski, J. Kalinowski

    We discuss a general two-Higgs-doublet model with CP violation in the Higgs sector. In general, the three neutral Higgs fields of the model all mix and the resulting physical Higgs bosons have no definite CP properties. We derive a new sum rule relating Yukawa and Higgs-Z couplings which implies that a neutral Higgs boson cannot escape detection at an e^+e^-

  23. C. Giunti, C. W. Kim, U. W. Lee, V. A. Naumov

    It is shown that the high-Delta m^2 part of the large mixing angle MSW solution of the solar neutrino problem is disfavored by the Super-Kamiokande data for low-energy upward-going events. A quantitative bound is obtained in the three-neutrino scheme with a negligibly small element U_{e3} of the neutrino mixing matrix, as indicated by the result of the CHOOZ

  24. K. Farakos, G. Koutsoumbas, N. Mavromatos, A. Momen

    The enhancement of the fermionic condensate due to the presence of both homogeneous and non-homogeneous external magnetic fields is studied for three-dimensional QED.

  25. Don N. Page

    Coupled ordinary differential equations are derived for the distant gravitational interaction of a compact object of mass M and charge Q with an initially straight, infinitely long, cosmic string of tension mu << 1/G = 1, when the relative velocities are very low compared to the speed of light c = 1. (An intermediate result of this derivation is that any loc

  26. Jerzy Lewandowski, Jacek Wisniewski

    This work completes the task of solving locally the Einstein-Ashtekar equations for degenerate data. The two remaining degenerate sectors of the classical 3+1 dimensional theory are considered. First, with all densitized triad vectors linearly dependent and second, with only two independent ones. It is shown how to solve the Einstein-Ashtekar equations compl

  27. Luis O. Pimentel

    In this work cosmological models are considered for the low energy string cosmological effective action (tree level) in the absence of dilaton potential. A two parametric non-diagonal family of analytic solutions is found. The curvature is non singular, however the string coupling diverges exponentially.

  28. Jose M M Senovilla, Raul Vera

    Following a recent work in which it is shown that a spacetime admitting Lie-group actions may be disjointly decomposed into a a closed subset with no interior plus a dense finite union of open sets in each of which the character and dimension of the group orbits as well as the Petrov type are constant, the aim of this work is to include the Segre types of th

  29. V. V. Okorokov

    Qualitativ arguments are presented which show the incompatibility of the positive results obtaned in experiments on the gravitational redshift of photones and in experiments investigating the behavior of clocks in the gravitational field.

  30. Hwei-jang Yo, James M. Nester

    The Hamiltonian constraint formalism is used to obtain the first explicit complete analysis of non-trivial viable dynamic modes for the Poincaré gauge theory of gravity. Two modes with propagating spin-zero torsion are analyzed. The explicit form of the Hamiltonian is presented. All constraints are obtained and classified. The Lagrange multipliers are derive

  31. Manfred Requardt

    In the following we are going to describe how macroscopic space-time is supposed to emerge as an orderparameter manifold or superstructure floating in a stochastic discrete network structure. As in preceeding work (mentioned below), our analysis is based on the working philosophy that both physics and the corresponding mathematics have to be genuinely discre

  32. T. Shimomura, T. Okamura, T. Mishima, H. Ishihara

    We investigate whether the generalized second law is valid, using two dimensional black hole spacetime, irrespective of models. A time derivative form of the generalized second law is formulated and it is shown that the law might become invalid. The way to resolve this difficulty is also presented and discussed.

  33. V. A. Berezin, A. M. Boyarsky, A. Yu. Neronov

    We develop a method for constructing asymptotic solutions of finite-difference equations and implement it to a relativistic Schroedinger equation which describes motion of a selfgravitating spherically symmetric dust shell. Exact mass spectrum of black hole formed due to the collapse of the shell is determined from the analysis of asymptotic solutions of the

  34. Alexander V. Bogdanov, Nick Yu. Bykov, Igor A. Grishin, Gregory O. Khanlarov

    The general scheme of two-level parallelization (TLP) for direct simulation Monte Carlo of unsteady gas flows on shared memory multiprocessor computers has been described. The high efficient algorithm of parallel independent runs is used on the first level. The data parallelization is employed for the second one. Two versions of TLP algorithm are elaborated

  35. Martin Wechsler, Peter Schauble

    A theoretic framework for multimedia information retrieval is introduced which guarantees optimal retrieval effectiveness. In particular, a Ranking Principle for Distributed Multimedia-Documents (RPDM) is described together with an algorithm that satisfies this principle. Finally, the RPDM is shown to be a generalization of the Probability Ranking principle

  36. Ulrich Schiel, Ianna M. Sodre Ferreira de Souza, Edberto Ferneda

    With the growing significance of digital libraries and the Internet, more and more electronic texts become accessible to a wide and geographically disperse public. This requires adequate tools to facilitate indexing, storage, and retrieval of documents written in different languages. We present a method for semi-automatic indexing of electronic documents and

  37. Not Available

    withdrawn by author

  38. V. J. Emery, S. A. Kivelson

    It is argued that a new mechanism and many-body theory of superconductivity are required for doped correlated insulators. Here we review the essential features of and the experimental support for such a theory, in which the physics is driven by the kinetic energy.

  39. Mikito Koga, Daniel L. Cox

    We investigate a two-channel Anderson impurity model with a $5f^1$ magnetic and a $5f^2$ quadrupolar ground doublet, and a $5f^2$ excited triplet. Using the numerical renormalization group method, we find a crossover to a non-Fermi liquid state below a temperature $T^*$ varying as the $5f^2$ triplet-doublet splitting to the 7/2 power. To within numerical acc

  40. Burkhard Doliwa, Andreas Heuer

    We present new simulation results on a hard sphere system at high densities. Using three-time correlations, we can account for the anomalous diffusion, which results from a homogeneous back-dragging effect. Furthermore, we calculate the non-gaussian parameter and connect it to the existence of dynamic heterogeneities.

  41. D. M. Kagan, L. B. Ioffe, M. V. Feigel&#39;man

    We show that the ground state of the periodic long range Josephson array frustrated by magnetic field is a glass for a sufficiently large Josephson energies despite the absence of a quenched disorder. Like superconductors, this glass state has non-zero phase stiffness and Meissner response; for smaller Josephson energies the glass &#34;melts&#34; and the gro

  42. Daniel F. Agterberg

    There now exists a wealth of experimental evidence that Sr_2RuO_4 is an odd-parity superconductor. Experiments further indicate that among the bands stemming from the Ru {xy,xz,yz} orbitals, the portion of the Fermi surface arising from the xy orbitals exhibits a much larger gap than the portions of the Fermi surface arising from the {xz,yz} orbitals. In thi

  43. J. Ruostekoski, J. Javanainen

    We study propagation of light in a Fermi-Dirac gas at zero temperature. We analytically obtain the leading density correction to the optical linewidth. This correction is a direct consequence of the quantum statistical correlations of atomic positions that modify the optical interactions between the atoms at small interatomic separations. The gas exhibits a

  44. Andreas Schadschneider

    The Nagel-Schreckenberg model is a simple cellular automaton for a realistic description of single-lane traffic on highways. For the case $v_{max}=1$ the properties of the stationary state can be obtained exactly. For the more relevant case $v_{max}>1$, however, one has to rely on Monte Carlo simulations or approximative methods. Here we study several analyt

  45. C. P. Moca, I. Tifrea, M. Crisan

    Using the renormalization approach proposed by Millis for the itinerant electron systems we calculated the specific heat coefficient $γ(T)$ for the magnetic fluctuations with susceptibility $χ^{-1}\sim |δ+ω|^α+f(q)$ near the Lifshitz point. The constant value obtained for $α=4/5$ and the logarithmic temperature dependence, specific for the non-Fermi behavior

  46. U. Al Khawaja, C. J. Pethick, H. Smith

    We investigate the structure and collective modes of a planar surface of a trapped Bose-Einstein condensed gas at zero temperature. In the long-wavelength limit we find a mode similar to the gravity wave on the surface of a fluid with the frequency $ω$ and the wavenumber $q$ related by $ω^2=Fq/m$. Here $F$ is the force due to the confining potential at the s

  47. J. Schiøtz, T. Vegge, F. D. Di Tolla, K. W. Jacobsen

    Nanocrystalline metals, i.e. metals in which the grain size is in the nanometer range, have a range of technologically interesting properties including increased hardness and yield strength. We present atomic-scale simulations of the plastic behavior of nanocrystalline copper. The simulations show that the main deformation mode is sliding in the grain bounda

  48. Bikas K. Chakrabarti, Robin B. Stinchcombe

    Following the observations of the self-similarity in various length scales in the roughness of the fractured solid surfaces, we propose here a new model for the earthquake. We demonstrate rigorously that the contact area distribution between two fractal surfaces follows an unique power law. This is then utilised to show that the elastic energy releases for s

  49. A. Honecker

    Plateaux in the magnetization curves of the square, triangular and hexagonal lattice spin-1/2 XXZ antiferromagnet are investigated. One finds a zero magnetization plateau (corresponding to a spin-gap) on the square and hexagonal lattice with Ising-like anisotropies, and a plateau with one third of the saturation magnetization on the triangular lattice which

  50. V. Zhuravlev, T. Maniv

    The melting of the Abrikosov vortex lattice in a 2D type-II superconductor at high magnetic fields is studied analytically within the framework of the phenomenological Ginzburg-Landau theory. It is shown that local phase fluctuations in the superconducting order parameter, associated with low energies sliding motions of Bragg chains along the principal cryst

  51. M. Leadbeater, V. I. Falko, C. J. Lambert

    Conductance fluctuations, localization and statistics of Lyapunov exponents are studied numerically in pure metallic wires with rough boundaries (quasi-ballistic wires). We find that the correlation energy of conductance fluctuations scales anomalously with the sample dimensions, indicating the role of Lévy flights. Application of a magnetic field deflects t

  52. Leon Balents

    Band theory predicts an inverse square root van Hove singularity in the tunneling density of states at the minimum energy of an unoccupied subband in a one-dimensional quantum wire. With interactions, an orthogonality catastrophe analogous to the x-ray edge effect for core levels in a metal strongly reduces this singularity by a power B of the energy above t

  53. M. K. Srivastava, R. K. Bhaduri, J. Law, M. V. N. Murthy

    We consider N fermions in a two-dimensional harmonic oscillator potential interacting with a very short-range repulsive pair-wise potential. The ground-state energy of this system is obtained by performing a Thomas-Fermi as well as a self-consistent Hartree-Fock calculation. The two results are shown to agree even for a small number of particles. We next use

  54. Koichi Nakamura, Yoshiya Yamanaka

    The particle distribution in a Bose condensate under the trapping potential and its time evolution after switching off the trapping potential suddenly are calculated. We investigate the problem from the viewpoint of quantum field theory,using a model of self-interacting neutral boson field. Within the approximation of retainng the most dominant term in the H

  55. F. Leyvraz, R. A. Mendez-Sanchez, T. H. Seligman

    We extend the application of the concept of structural invariance to bounded time independent systems. This concept, previously introduced by two of us to argue that the connection between random matrix theory and quantum systems with a chaotic classical counterpart is in fact largely exact in the semiclassical limit, is extended to the energy spectra of bou

  56. J. Main

    Harmonic inversion is introduced as a powerful tool for both the analysis of quantum spectra and semiclassical periodic orbit quantization. The method allows to circumvent the uncertainty principle of the conventional Fourier transform and to extract dynamical information from quantum spectra which has been unattainable before, such as bifurcations of orbits

  57. Simon Portegies Zwart, Edward van den Heuvel

    By comparing relative rates of supernovae versus formation rates of single radio pulsars, recycled pulsars, binary pulsars and X-ray binaries we put strong limits on the progenitors of radio pulsars and on the requirement of an asymmetry in the supernova. The assumption that radio pulsars are only formed in type Ib and type Ic supernovae from interacting bin

  58. HongSheng Zhao

    If the Universe has a significant baryonic dark component in the form of compact objects in galaxy halos (machos), then there is a minute chance (about $10^{-7}$) that one of the Galactic machos passes sufficiently close to our line of sight to a star out of some $10^7$ monitored stars in the Magellanic Clouds (MCs) that it brightens by more than 0.3 magnitu

  59. Gordon T. Richards, Donald G. York, Brian Yanny, Ronald I. Kollgaard

    We present the results of a study of QSO Absorption Line Systems (QSOALSs) with respect to intrinsic QSO properties using an updated catalog of data in the literature. We have searched the literature for 6 and 20 cm radio flux densities and have studied 20 cm maps from the FIRST VLA Survey in order to compare the absorption properties with radio luminosity,

  60. G. Piotto, M. Zoccali

    From a combination of deep Hubble Space Telescope V and I images with groundbased images in the same bands, we have obtained color-magnitude diagrams of M10, M22, and M55, extending from just above the hydrogen burning limit to the tip of the red giant branch, down to the white dwarf cooling sequence. We have used the color-magnitude arrays to extract main s

  61. Sofia Kirhakos, John N. Bahcall, Donald P. Schneider, Jerome Kristian

    Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space Telescope (HST) are presented for three radio-loud quasars: 3C 48 (z=0.367), B2 1425+267 (z=0.366), and 3C 345 (z=0.594). All three quasars have luminous (~4 L^*) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C 345) or interacting (3C 48), and all hosts are 0.5 - 1.0 m

  62. S. Chapelon, T. Contini, E. Davoust

    We have measured the bar lengths and widths of 125 barred galaxies observed with CCDs. The dependence of bar strength (identified with bar axis ratio) on morphological type, nuclear activity, central and mid-bar surface brightness is investigated. The properties of the bars are best explained if the sample is divided into early- (< SBbc) and late-type galaxi

  63. Max Pettini

    I review measurements of element abundances in different components of the high redshift universe, including the Lyman alpha forest, damped Lyman alpha systems, and Lyman break galaxies. Although progress is being made in all three areas, recent work has also produced some surprises and shown that established ideas about the nature of the damped Lyman alpha

  64. L. Bergstrom

    Dark matter detection experiments are getting ever closer to the sensitivity needed to detect the primary particle physics candidates for nonbaryonic dark matter. Indirect detection methods include searching for antimatter and gamma rays, in particular gamma ray lines, in cosmic rays and high-energy neutrinos from the centre of the Earth or Sun caused by acc

  65. Martin Zwaan, Marc Verheijen, Frank Briggs

    We present a measurement of the HI column density distribution function, f(N), at the present epoch for column densities log N > 20 cm^-2. These high column densities compare to those measured in damped Ly alpha lines seen in absorption against background quasars. Although observationally rare, it appears that the bulk of the neutral gas in the Universe is a

  66. G. K. T. Hau, D. Carter, M. Balcells

    We report on the discovery of a rapidly co-rotating stellar and gas component in the nucleus of the shell elliptical NGC2865. The stellar component extends ~ 0.51/h100 kpc along the major axis, and shows depressed velocity dispersion and absorption line profiles skewed in the opposite sense to the mean velocity. Associated with it is a young stellar populati

  67. Jan Wagemans, Cyriel Wagemans, Ronald Bieber, Peter Geltenbort

    The 17O(n_th,alpha)14C reaction cross section was determined at the high flux reactor of the ILL in Grenoble relative to the known 14N(n_th,p)14C cross section. The 17O(n_th,alpha)14C measurements were performed with several highly enriched oxygen gas samples and the flux calibration was done with 14N_2 from the air. This resulted in a precise value of (244+

  68. Wenxian Lu, Slavek M. Rucinski

    Radial velocity data are presented for 10 W UMa-type systems: GZ And, V417 Aql, LS Del, EF Dra, V829 Her, FG Hya, AP Leo, UV Lyn, BB Peg, AQ Psc, together with preliminary, circular-orbit determinations of spectroscopic elements, with the main goal of obtaining mean radial velocities and mass-ratios for these systems. This is the first part of a series which

  69. H. Aceves, J. Perea

    The two most common mass estimators that use velocity dispersions and positions of objects in a stellar system, the virial mass estimator (VME) and the projected mass estimator (PME), are revisited and tested using N-body experiments. We consider here only spherical, isolated, and isotropic velocity dispersion systems. We have found that the PME can overesti

  70. M. L. Graesser

    It has been proposed recently that the scale of strong gravity can be very close to the weak scale. Dimensions of sizes anywhere from $\sim $mm to $\sim $TeV$^{-1}$ can be populated by bulk gravitons, vector bosons and fermions. In this paper the one-loop correction of these bulk particles to the muon magnetic moment (MMM) are investigated. In all the scenar

  71. T. Osada, Y. Hama

    Electromagnetic field produced in high-energy heavy-ion collisions contains much useful information, because the field can be directly related to the motion of the matter in the whole stage of the reaction. One can divide the total electromagnetic field into three parts, i.e., the contributions from the incident nuclei, non-participating nucleons and charged

  72. Tom Blum, Amarjit Soni, Matthew Wingate

    We present a first calculation of the strange quark mass using domain wall fermions. This paper contains an overview of the domain wall discretization and a pedagogical presentation of the perturbative calculation necessary for computing the mass renormalization. We combine the latter with numerical simulations to estimate the strange quark mass. Our final r

  73. Eric H. Neilsen,, Zlatan I. Tsvetanov

    This Letter presents the color distributions of the globular cluster (GC) systems of 12 Virgo elliptical galaxies, measured using data from the Hubble Space Telescope. Bright galaxies with large numbers of detected GC&#39;s show two distinct cluster populations with mean V-I colors near 1.01 and 1.26. The GC population of M86 is a clear exception; its color

  74. Joseph A. Minahan

    We argue that there are generic solutions to the type 0 gravity equations of motion that are confining in the infrared and have log scaling in the ultraviolet. The background curvature generically diverges in the IR. Nevertheless, there exist solutions where higher order string corrections appear to be exponentially suppressed in the IR with respect to the l

  75. A. H. Mueller

    The main part of this talk is a review and summary of how QCD is used in two main areas of nuclear physics, namely in determining the quark flavor and spin content of the proton and in ultrarelativistic heavy ion collisions. Brief comments are made concerning effective theories in hadron physics and on the separation of various twists in using the operator p

  76. Daniel Kabat, Gilad Lifschytz

    We discuss the gauge theory mechanisms which are responsible for the causal structure of the dual supergravity. For D-brane probes we show that the light cone structure and Killing horizons of supergravity emerge dynamically. They are associated with the appearance of new light degrees of freedom in the gauge theory, which we explicitly identify. This provid

  77. S. J. Burby

    We present an analytic expression for the four-jet rate in e+e- annihilation, calculated using the coherent branching formalism in the Durham scheme. Our result resums all the leading and next-to-leading kinematic logarithms to all orders in the QCD strong coupling constant.

  78. Robert Graham, Dan F. Walls

    We study the dynamics of a magnetically trapped Bose-Einstein condensate in the presence of an external electromagnetic field coupling trapped, untrapped and antitrapped Zeeman sublevels. For large condensates an approximate analytical solution of the coupled Gross-Pitaevskii equations is given in the regime of strong outcoupling. The theory is developed for

  79. Hoi-Kwong Lo, Sandu Popescu

    Entanglement bits or ``ebits&#39;&#39; have been proposed as a quantitative measure of a fundamental resource in quantum information processing. For such an interpretation to be valid, it is important to show that the same number of ebits in different forms or concentrations are inter-convertible in the asymptotic limit. Here we draw attention to a very impo

  80. W. Beenakker, F. A. Berends, A. P. Chapovsky

    We calculate the one-loop non-factorizable QCD corrections to the production and decay of pairs of top quarks at various collider experiments. These non-factorizable corrections interconnect the different production and decay stages of the off-shell top-pair production processes. This in particular affects the invariant-mass distributions of the off-shell to

  81. Eef van Beveren, George Rupp

    We present flavour-symmetric couplings for the OZI-allowed three-meson vertices of effective meson theories, which for the case of the two-meson channels to which the flavour-singlet scalar meson couples, are endowed with a correction factor with respect to the standard formula.

  82. R. S. Thorne

    I review the various methods for taking account of finite quark masses in DIS and related processes. I pay particular attention to the so-called variable flavour number schemes (VFNS) which are designed to extrapolate smoothly from the region near threshold of production of heavy quark pairs to the region where the quarks become effectively massless.

  83. Michele Caselle, Roberto Tateo, Stefano Vinti

    We present a Monte Carlo study of various universal amplitude ratios of the two dimensional q=4 Potts model. We simulated the model close to criticality in both phases taking care to keep the systematic errors, due to finite size effects and logarithmic corrections in the scaling functions, under control. Our results are compatible with those recently obtain

  84. Stefan Forste

    We study the potential between a string and an anti-string source in M5-theory by using the adS/CFT duality conjecture. We find that the next to leading order corrections in a saddle point approximation renormalize the classical result.

  85. Claude Aslangul

    The single-file problem of N particles in one spatial dimension is analyzed, when each particle has a randomly distributed diffusion constant D sampled in a density $ρ(D)$. The averaged one-particle distributions of the edge particles and the asymptotic ($N\gg 1$) behaviours of their transport coefficients (anomalous velocity and diffusion constant) are stro

  86. D. R. Grempel, M. J. Rozenberg

    We study a mean-field model of a Kondo alloy using numerical techniques and analytic approximations. In this model, randomly distributed magnetic impurities interact with a band of conduction electrons and have a residual RKKY coupling of strength $J$. This system has a quantum critical point at $J=J_{c} \sim T_{K}^0$, the Kondo scale of the problem. The $T$

  87. Deepak Dhar

    We present some analytical results for the stochastic sandpile model, studied earlier by Manna. In this model, the operators corresponding to particle addition at different sites commute. The eigenvalues of operators satisfy a system of coupled polynomial equations. For an L X L square, we construct a nontrivial toppling invariant, and hence a ladder operato

  88. Andre Lukas, Burt A. Ovrut, Daniel Waldram

    Inflationary solutions are constructed in a specific five-dimensional model with boundaries motivated by heterotic M-theory. We concentrate on the case where the vacuum energy is provided by potentials on those boundaries. It is pointed out that the presence of such potentials necessarily excites bulk Kaluza-Klein modes. We distinguish a linear and a non-lin

  89. Indranath Chaudhuri, Indrani Bose

    Recently, Lenski et al have carried out an experiment on bacterial evolution. Their findings support the theory of punctuated equilibrium in biological evolution. We show that the M=2 Bak-Sneppen model can explain some of the experimental results in a qualitative manner.

  90. T. Hatsuda, T. Kunihiro

    It is shown that an enhancement in the spectral function near 2$m_π$ threshold in the I=J=0 channel is a good signal of the partial restoration of chiral symmetry in nuclear medium. Several experiments are discussed to detect the enhancement, which uses hadron-nucleus and photo-nucleus reactions.

  91. Glenisson de Oliveira, Jan M. L. Martin, Frank de Proft, Paul Geerlings

    A benchmark ab initio and density functional (DFT) study has been carried out on the electron affinities of the first- and second-row atoms. The ab initio study involves basis sets of $spdfgh$ and $spdfghi$ quality, extrapolations to the 1-particle basis set limit, and a combination of the CCSD(T), CCSDT, and full CI electron correlation methods. Scalar rela

  92. Martin Schlichenmaier

    For phase-space manifolds which are compact Kaehler manifolds relations between the Berezin-Toeplitz quantization and the quantization with the help of Berezin&#39;s coherent states and symbols are studied. First the results on the Berezin-Toeplitz quantization of arbitrary compact Kaehler manifolds due to Bordemann, Meinrenken and Schlichenmaier are recalle

  93. Deepak Jain, N. Panchapakesan, S. Mahajan, V. B. Bhatia

    Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift $ < z >$ of the GRBs. In this paper we investigate the effect of evolving lenses on the $< z >$ of GRBs in different cosmological models of universe. The cosmological parameters $Ω$ and $Λ$ have an effect on the $< z >$ of GR

  94. J. van Elp, Arata Tanaka

    It has been generally accepted that the threshold structure observed in the oxygen K edge X-ray absorption spectrum in 3d transition metal oxides represents the electronic structure of the 3d transition metal. There is, however, no consensus about the correct description. We present an interpretation, which includes both ground state hybridization and electr

  95. Yosef Nir, Yael Shadmi

    The experimental data on atmospheric and solar neutrinos are used to test the framework of non-anomalous Abelian horizontal gauge symmetries with only three light active neutrinos. We assume that the hierarchy in mass-squared splittings is not accidental and that the small breaking parameters are not considerably larger than 0.2. We find that the small angle

  96. Aurel Bulgac

    In the limit when the two-body scattering length $a$ is negative and much larger than the effective two-body interaction radius the contribution to the ground state energy due to the three-body correlations is given by the Efimov effect. For particular values of the diluteness parameter $ρ|a|^3$ the three-body contribution can become the dominant term of the

  97. Kiwoon Choi

    A slow-rolling scalar field ($Q\equiv$ Quintessence) with potential energy $V_Q\sim (3\times 10^{-3} {\rm eV})^4$ has been proposed as the origin of accelerating universe at present. We investigate the effective potential of $Q$ in the framework of supergravity model including the quantum corrections induced by generic (nonrenormalizable) couplings of $Q$ to

  98. M. Jurcisin, D. I. Kazakov

    We consider the infrared quasi fixed point solutions of the renormalization group equations for the Yukawa couplings and soft supersymmetry breaking parameters in the MSSM in the \underline{large $\tanβ$} regime. The existence of IR quasi fixed points together with the values of gauge couplings, third generation quarks, lepton and Z-boson masses allows one t

  99. D0 Collaboration, B. Abbott et al

    Using data corresponding to an integrated luminosity of 79 pb-1, D0 has searched for events containing multiple jets and large missing transverse energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos

  100. Y. Lee, T. M. Haard, W. P. Halperin, J. A. Sauls

    We report the discovery of the acoustic Faraday effect in superfluid 3He-B. The observation of this effect provides the first direct evidence for propagating transverse acoustic waves in liquid 3He, a mode first predicted by Landau in 1957. The Faraday rotation is large and observable because of spontaneously broken spin-orbit symmetry in 3He-B. We compare t