July 1999 arXiv papers — page 2

C. Alexandrou, M. D'Elia, Ph. de Forcrand

We show remnants of chiral symmetry breaking in the center-projected theory. We construct and study an unambiguous definition of center vortices.

The SLD Collaboration, K. Abe

We report a new measurement of A_b using data obtained by SLD in 1997-98. This measurement uses a vertex tag technique, where the selection of a b hemisphere is based on the reconstructed mass of the bottom hadron decay vertex. The method uses the 3D vertexing capabilities of SLD's CCD vertex detector and the small and stable SLC beams to obtain a high b

The SLD Collaboration, K. Abe

We report a new measurement of A_c using data obtained by SLD in 1993-98. This measurement uses a vertex tag technique, where the selection of a c hemisphere is based on the reconstructed mass of the charm hadron decay vertex. The method uses the 3D vertexing capabilities of SLD's CCD vertex detector and the small and stable SLC beams to obtain a high c-

The OPAL collaboration, G. Abbiendi

The process e+e- to 2 (or 3) gammas is studied using data recorded with the OPAL detector at LEP. The data sample taken at a centre-of-mass energy of 189 GeV corresponds to a total integrated luminosity of 178 pb-1. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95%

Maja Buric, Voja Radovanovic

We study the hamiltonian and constraints of spherically symmetric dilaton gravity model. We find the ADM mass of the solution representing the Schwarzchild black hole in thermal equilibrium with the Hawking radiation.

J. A. Vickers, J. P. Wilson

Solutions of the wave equation in a space-time containing a thin cosmic string are examined in the context of non-linear generalised functions. Existence and uniqueness of solutions to the wave equation in the Colombeau algebra G is established for a conical space-time and this solution is shown to be associated to a distributional solution. A concept of gen

Christoph Best

Representing scientific data sets efficiently on external storage usually involves converting them to a byte string representation using specialized reader/writer routines. The resulting storage files are frequently difficult to interpret without these specialized routines as they do not contain information about the logical structure of the data. Avoiding s

V. Gurarie

We present evidence that two dimensional Dirac fermions in the presence of random Abelian gauge potential exhibit a phase transition when the disorder strength exceeds a certain critical value. We argue that this phase transition has novel properties unique to disordered systems. It resembles in many ways the transition from dilute to dense polymers phase in

Michael Lachmann, M. E. J. Newman, Cristopher Moore

It has been well-known since the pioneering work of Claude Shannon in the 1940s that a message transmitted with optimal efficiency over a channel of limited bandwidth is indistinguishable from random noise to a receiver who is unfamiliar with the language in which the message is written. In this letter we demonstrate an equivalent result about electromagneti

N. R. Cooper, N. K. Wilkin

We study the properties of rotating Bose-Einstein condensates in parabolic traps, with coherence length large compared to the system size. In this limit, it has been shown that unusual groundstates form which cannot be understood within a conventional many-vortex picture. Using comparisons with exact numerical results, we show that these groundstates can be

D. S. Golubev, A. D. Zaikin

We point out a close physical and formal similarity between the problems of electron tunneling in the effective environment and the weak localization effects in the presence of interactions. In both cases the results are expressed in terms of the ``energy probability distribution function'' $P(E)$ which has a finite width even at T=0 due to interacti

Pier A. Mello, Yoseph Imry, Boris Shapiro

We study the problem of electronic conduction in mesoscopic systems when the electrons are allowed to interact not only with static impurities, but also with a scatterer (a phase breaker(PB)) that possesses internal degrees of freedom. We first analyze the role of the PB in reducing the coherent interference effects in a one-electron quantum-mechanical syste

Gennady P. Berman, Vladimir I. Tsifrinovich

The magnetic moment of a single spin interacting with a cantilever in magnetic resonance force microscopy (MRFM) experiences quantum jumps in orientation rather than smooth oscillations. These jumps cannot be detected by a conventional MRFM based on observation of driven resonant oscillations of a cantilever. In this paper, we propose a method which will all

V. P. Mineev

The Landau expansion for the free energy of the superconducting mixed state near the upper critical field in powers of the square modulus of the order parameter averaged over Abrikosov lattice is derived. The analytical calculations has been carried out in frame of Gor'kov formalism for 3-dimensional isotropic BCS model beyond the limits of quasiclassica

A. A. Aligia, Liliana Arrachea

We study a Hubbard hamiltonian, including a quite general nearest-neighbor interaction, parametrized by repulsion V, exchange interactions Jz, Jperp, bond-charge interaction X and hopping of pairs W. The case of correlated hopping, in which the hopping between nearest neighbors depends upon the occupation of the two sites involved, is also described by the m

I. Campillo, J. M. Pitarke, A. Rubio, E. Zarate

We report a first-principles description of inelastic lifetimes of excited electrons in real Cu and Al, which we compute, within the GW approximation of many-body theory, from the knowledge of the self-energy of the excited quasiparticle. Our full band-structure calculations indicate that actual lifetimes are the result of a delicate balance between localiza

U. Schneider, P. Lunkenheimer, J. Hemberger, A. Loidl

In this work we present a thorough investigation of the mixed system of Rochelle salt doped with ammonium, with 0<=x<=1 for [Na(K{1-x}(NH4)x)C4H4O6 * 4H2O]. This interesting system is known to exhibit a rich phase diagram with a variety of polar and non-polar phases. However, most of the earlier investigations date back many decades and the experimental adva

R. Urbanczik

Supervised online learning with an ensemble of students randomized by the choice of initial conditions is analyzed. For the case of the perceptron learning rule, asymptotically the same improvement in the generalization error of the ensemble compared to the performance of a single student is found as in Gibbs learning. For more optimized learning rules, howe

B. Reulet, A. Yu. Kasumov, M. Kociak, R. Deblock

We show that it is possible to detect mechanical bending modes on 1 micron long ropes of single walled-carbon nanotubes suspended between 2 metallic contacts. This is done by measuring either their dc resistance in a region of strong temperature dependence (in the vicinity of superconducting or metal-insulator transition), or their critical current. The vibr

Keith A. Benedict, R. K. Hills, C. J. Mellor

We describe a theoretical framework for the interpretation of time-resolved phonon absorption experiments carried out in the fractional quantum Hall regime of a magnetically quantized two-dimensional electron system (2des). The only phonons which can be absorbed at low temperature are those whose energies exceed the magnetoroton gap predicted by Girvin, MacD

V. Pasquier

We consider the problem of Bosonic particles interacting repulsively in a strong magnetic field at the filling factor $ν=1.$ We project the system in the Lowest Landau Level and map the dynamics into an interacting Fermion system. We study the resulting Hamiltonian in the Hartree--Fock approximation in the case of a $δ$ repulsive potential. The physical pict

S. Pilgram, W. Belzig, C. Bruder

We calculate the local density of states (LDOS) of a superconductor-normal metal sandwich at arbitrary impurity concentration. The presence of the superconductor induces a gap in the normal metal spectrum that is proportional to the inverse of the elastic mean free path $l$ for rather clean systems. For a mean free path much shorter than the thickness of the

A. N. Rubtsov, J. Hlinka, T. Janssen

The phase transition in a 3D array of classical anharmonic oscillators with harmonic nearest-neighbour coupling (discrete $ϕ^4$ model) is studied by Monte Carlo (MC) simulations and by analytical methods. The model allows to choose a single dimensionless parameter a determining completely the behaviour of the system. Changing a from 0 to $+\infty$ allows to

Kiyomi Okamoto, Atsuhiro Kitazawa

We study the magnetization plateau at a third of the saturation magnetization of the S=1/2 trimerized XXZ spin chain at T=0. The appearance of the plateau depends on the values of the XXZ anisotropy and the magnitude of the trimerization. This plateauful-plateauless transition is a quantum phase transition of the Berezinskii-Kosterlitz-Thouless type, which i

M. T. Batchelor, M. Maslen

We show that a 2-leg ladder hamiltonian introduced recently by Albeverio and Fei (cond-mat/9807341) can be made to satisfy the Hecke algebra. As a result we have found an equivalent representation of the eigenspectrum in terms of the spin-1/2 antiferromagnetic XXZ chain at $Δ= - 5/3$. The values of thermodynamic quantities such as the ground state energy and

M. A. Korotin, V. I. Anisimov, T. Saha-Dasgupta, I. Dasgupta

We have performed ab-initio calculations of the electronic structure and exchange couplings in the layered vanadates CaV2O5 and MgV2O5. Based on our results we provide a possible explanation of the unusual magnetic properties of these materials, in particular the large difference in the spin gap between CaV2O5 and MgV2O5.

Thomas B. Schroeder, Jeppe C. Dyre

Recent scaling results for the AC conductivity of ionic glasses by Roling et al. [Phys. Rev. Lett. vol 78, 2160 (1997)] and Sidebottom [Phys. Rev. Lett. vol 82, 3653 (1999)] are discussed. It is shown that Sidebottom&#39;s version of scaling is completely general. A new analytical approximation to the universal AC conductivity of hopping in the extreme disor

H. Hong, M. Y. Choi, K. Park, B. -G. Yoon

We study the noise effects in a driven system of globally coupled oscillators, with particular attention to the interplay between driving and noise. The self-consistency equation for the order parameter, which measures the collective synchronization of the system, is derived; it is found that the total order parameter decreases monotonically with noise, indi

Yukiko Umeno, Heng Fan, Miki Wadati

Exact integrability and algebraic Bethe ansatz of the small-polaron model with the open boundary condition are discussed in the framework of the quantum inverse scattering method (QISM). We employ a new approach where the fermionic R-operator which consists of fermion operators is a key object. It satisfies the Yang-Baxter equation and the reflection equatio

M. P. Kozlovskii, I. V. Pylyuk, V. V. Dukhovii

Calculation of thermodynamic functions of the three-dimensional Ising ferromagnet above and below critical temperature is performed in the approximation of sixfold basis distribution ($ρ^6$ model). Comparison with the results for the $ρ^4$ model indicates that dependence of the thermodynamic functions on the renormalization group parameter $s$ becomes weaker

Anatoly A. Svidzinsky, Alexander L. Fetter

Based on the method of matched asymptotic expansion and on a time-dependent variational analysis, we study the dynamics of a vortex in the large-condensate (Thomas-Fermi) limit. Both methods as well as an analytical solution of the Bogoliubov equations show that a vortex in a trapped Bose-Einstein condensate has formally unstable normal mode(s) with positive

Gregory L. Eyink, David J. Thomson

It has been generally assumed, since the work of von Karman and Howarth in 1938, that free decay of fully-developed turbulence is self-similar. We present here a simple phenomenological model of the decay of 3D incompressible turbulence, which predicts breakdown of self-similarity for low-wavenumber spectral exponents $n$ in the range $n_c<n<4$, where $n_c$

Martin J. Bünner, R. Hegger

A method to estimate Lyapunov spectra from spatio-temporal data is presented, which is well-suited to be applied to experimental situations. It allows to characterize the high-dimensional chaotic states, with possibly a large number of positive Lyapunov exponents, observed in spatio-temporal chaos. The method is applied to data from a coupled map lattice.

Martin J. Bünner, Wolfram Just

We present the linear-stability analysis of synchronised states in coupled time-delay systems. There exists a synchronisation threshold, for which we derive upper bounds, which does not depend on the delay time. We prove that at least for scalar time-delay systems synchronisation is achieved by transmitting a single scalar signal, even if the synchronised so

Dragos Iftimie, Genevieve Raugel

We consider the Navier-Stokes equations on thin 3D domains, supplemented mainly with purely periodic boundary conditions or with periodic boundary conditions in the thin direction and homogeneous Dirichlet conditions on the lateral boundary. We prove global existence and uniqueness of solutions for initial data and forcing terms, which are larger and less re

V. Kobelev, E. Romanov

A Langevin equation with a special type of additive random source is considered. This random force presents a fractional order derivative of white noise, and leads to a power-law time behavior of the mean square displacement of a particle, with the power exponent being noninteger. More general equation containing fractional time differential operators instea

H. K. C. Yee, M. D. Gladders, O. Lopez-Cruz

The color-magnitude relation (CMR) of early-type galaxies in clusters provides a powerful tool for finding clusters and determining photometric redshifts for clusters using two-filter imaging data. We demonstrate the high accuracy of photometric redshifts attainable using the CMR by applying the technique to a sample of 45 Abell clusters with known redshifts

S. M. Asida

Two-dimensional hydrodynamical simulations were made to calibrate the mixing length parameter for modeling red giant&#39;s convective envelope. As was briefly reported in Asida & Tuchman (97), a comparison of simulations starting with models integrated with different values of the mixing length parameter, has been made. In this paper more results are present

Hector Aceves

We present a preliminary report on the dynamical evolution of triplets of spiral galaxies that lead to merger remnants that resemble an elliptical. We find that large projected stellar tidal tails ~200 Kpc can develop during the binary formation, and up to ~350 Kpc in the third galaxy when this merges with the binary. When gas is treated as test-particles, g

S. Veilleux, J. Bland-Hawthorn, G. Cecil

We present direct kinematic evidence for bar streaming motions in two active galaxies with boxy stellar bulges. The Hawaii Imaging Fabry-Perot Interferometer was used on the Canada-France-Hawaii 3.6-m telescope and the University of Hawaii 2.2-m telescope to derive the two-dimensional velocity field of the line-emitting gas in the disks of the Sc galaxy NGC

E. Lastennet, D. Valls-Gabaud, T. Lejeune, E. Oblak

Three independent sets of stellar theoretical models are tested with well-detached systems of the Hyades open cluster: 51 Tau, V818 Tau, and $θ^2$ Tau. The choice of these objects is discussed and a statistical method is described and applied to the colour-magnitude diagram (CMD) of the selected stars, giving rise to contour levels in the metallicity-age pla

Julien Sylvestre, Justin Khoury, Shaun Lovejoy, Pierre Bastien

We present a study of the scaling properties of bipolar outflows, generic to the circumstellar environment of young stellar objects, and which are generally believed to be magnetohydrodynamically driven. Our work consists of a multifractal analysis of near-infrared light scattered by dust grains in the lobes of seven bipolar nebulae, namely GGD 18, V380 Orio

J. V. Wall, C. A. Jackson

A new method of deriving the cosmological evolution of radio AGN is described which is based on the premise of unified models for quasars and radio galaxies.

E. Garcia-Berro, E. Gaztanaga, J. Isern, O. Benvenuto

There are at least three ways in which a varying gravitational constant $G$ could affect the interpretation of the recent high-redhisft Type Ia supernovae results. If the local value of $G$ at the space-time location of distant supernovae is different, it would change both the thermonuclear energy release and the time scale of the supernova outburst. In both

Christopher A. Tout, Mario Livio, Ian A. Bonnell

The position of pre-main-sequence or protostars in the Hertzsprung--Russell diagram is often used to determine their mass and age by comparison with pre-main-sequence evolution tracks. On the assumption that the stellar models are accurate, we demonstrate that, if the metallicity is known, the mass obtained is a good estimate. However, the age determination

Shinji Koide, David L. Meier, Kazunari Shibata, Takahiro Kudoh

To investigate the formation mechanism of relativistic jets in active galactic nuclei and micro-quasars, we have developed a new general relativistic magnetohydrodynamic code in Kerr geometry. Here we report on the first numerical simulation of jet formation in a rapidly-rotating (a=0.95) Kerr black hole magnetosphere. We study cases in which the Keplerian a

Shinji Koide, David L. Meier, Kazunari Shibata, Takahiro Kudoh

Recent observations of Galactic Black Hole Candidates (BHCs) suggest that those that are superluminal jet sources have more rapid black hole spin rates than otherwise normal BHCs. This provides observational support for models of relativistic jet formation that extract rotational energy of the central black hole. To investigate this mechanism, we have develo

C. L. Fryer, A. Heger

We present the results from a series of two-dimensional core-collapse simulations using a rotating progenitor star. We find that the convection in these simulations is less vigorous because a) rotation weakens the core bounce which seeds the neutrino-driven convection and b) the angular momentum profile in the rotating core stabilizes against convection. The

Bradley C. Whitmore, Qing Zhang, Claus Leitherer, S. Michael Fall

The WFPC2 of the HST has been used to obtain high-resolution images of NGC 4038/4039 that go roughly 3 magnitudes deeper in V than previous observations made during Cycle 2 (-14 < M_V < -6). To first order the luminosity function (LF) is a power law, with exponent α= -2.12 +/- 0.04. However, after decoupling the cluster and stellar LFs, which overlap in the

Bo-Qiang Ma, Ivan Schmidt, Jian-Jun Yang

The quark flavor and spin distributions in octet baryons are calculated both in the SU(6) quark spectator diquark model and in a perturbative QCD (pQCD) based model. It is shown that the $Λ$ has the most significant difference in flavor structure at large $x$ between the two models, though the flavor and spin structure of other baryons can also provide tests

Pranab Ghosh

We introduce a multipolar scheme for describing the structure of stationary, axisymmetric, force-free black-hole magnetospheres in the ``3+1&#39;&#39; formalism. We focus here on Schwarzschild spacetime, giving a complete classification of the separable solutions of the stream equation. We show a transparent term-by-term analogy of our solutions with the fam

Tarek Ibrahim, Pran Nath

The one loop supersymmetric electro-weak correction to the anomalous magnetic moment of the muon is derived in the minimal N=1 supergravity unification with two CP violating phases. A numerical analysis of the CP violating effects on $g_μ-2$ is carried out with the cancellation mechanism to guarantee the satisfaction of the experimental limits on the electri

Daniel A. Lidar, David Bacon, Julia Kempe, K. Birgitta Whaley

The exchange interaction between identical qubits in a quantum information processor gives rise to unitary two-qubit errors. It is shown here that decoherence free subspaces (DFSs) for collective decoherence undergo Pauli errors under exchange, which however do not take the decoherence free states outside of the DFS. In order to protect DFSs against these er

Vassiliki Kalogera, Duncan Lorimer

In the context of assessing the detectability of the coalescence of two neutron stars (NS) by currently built gravitational-wave experiments, we present a way of obtaining an upper limit to the coalescence rate in the Galaxy. We consider the NS/NS progenitors just before the second supernova explosion. By combining our theoretical understanding of orbital dy

H. -O. Georgii, Y. Higuchi

We reconsider the percolation approach of Russo, Aizenman and Higuchi for showing that there exist only two phases in the Ising model on the square lattice. We give a fairly short alternative proof which is only based on FKG monotonicity and avoids the use of GKS-type inequalities originally needed for some background results. Our proof extends to the Ising

F. Simkovic, A. Raduta, M. Veselsky, Amand Faessler

Limitations of the Quasiparticle Random Phase Approximation (QRPA) are studied within an exactly solvable model, with a two body interaction of Fermi type. A special attention is paid to the violation of the Pauli exclusion principle (PEP) in solving the QRPA equation. A comparison of the exact solution, obtained by the diagonalization of a schematic nuclear

Davide Fabbri, Pietro Fre&#39;, Leonardo Gualtieri, Cesare Reina

In this paper we discuss candidate superconformal N=2 gauge theories that realize the AdS/CFT correspondence with M--theory compactified on the homogeneous Sasakian 7-manifolds M^7 that were classified long ago. In particular we focus on the two cases M^7=Q^{1,1,1} and M^7=M^{1,1,1}, for the latter the Kaluza Klein spectrum being completely known. We show ho

Ilya F. Ginzburg

I discuss, what really new could give Photon Colliders ($γγ$ and $eγ$) after LHC and \epe Linear Collider operations.

L. N. Bulaevskii, A. E. Koshelev, V. M. Vinokur, M. P. Maley

We consider the magnetic field dependence of the plasma resonance frequency in pristine and in irradiated Bi$_2$Sr$_2$CaCu$_2$O$_8$ crystals near $T_c$. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wander

Pasquale Di Bari, Paolo Lipari, Maurizio Lusignoli

The data on atmospheric neutrinos can be explained assuming the existence of oscillations between muon neutrinos and light sterile neutrinos with mixing close to maximal, and Delta_m^2 approximately equal to 3 E-3 (eV^2). This interpretation of the data is in potential conflict with the successes of big bang nucleosynthesis (BBN), since oscillations can resu

Masayuki Tanimoto

We propose comparing cosmological solutions in terms of their total spatial volumes $V(τ)$ as functions of proper time $τ$, assuming synchronous gauge, and with this intention evaluate the variations of $V(τ)$ about the Friedmann-Lema\^ıtre-Robertson-Walker (FLRW) solutions for dust. This can be done successfully in a simple manner without solving perturbati

Olaf Lechtenfeld, Alexander Sorin

A wide class of N=2 reductions of the supersymmetric KP hierarchy in N=1 superspace is described. This class includes a new N=2 supersymmetric generalization of the Toda chain hierarchy. The Lax pair representations of the bosonic and fermionic flows, local and nonlocal Hamiltonians, finite and infinite discrete symmetries, first two Hamiltonian structures a

L. R. Abramo, F. Finelli

We address some of the issues that appear in the study of back reaction in Schwarzschild backgrounds. Our main object is the effective energy-momentum tensor (EEMT) of gravitational perturbations. It is commonly held that only asymptotically flat or radiation gauges can be employed for these purposes. We show that the traditional Regge-Wheeler gauge for the

B. E. White

This talk gives a brief discussion of extended fracture functions, which parametrise the non-perturbative physics in the target fragmentation region of semi-inclusive DIS. In the forward limit z -> 1, it can be seen that fracture functions can be identified with insertions of composite operators. This enables polarised fracture functions to be used to test a

Jean-Michel Courty, Serge Reynaud

The drag free technique is used to force a proof mass to follow a geodesic motion. The mass is protected from perturbations by a cage, and the motion of the latter is actively controlled to follow the motion of the proof mass. We present a theoretical analysis of the effects of quantum fluctuations for this technique. We show that a perfect drag free operati

Sunil Mukhi, Nemani V. Suryanarayana

We examine string-theory orientifold planes of various types including the Sp and SO-odd planes, and deduce the gravitational Chern-Simons couplings on their world-volumes. Consistency checks are carried out in different spacetime dimensions using various dualities, including those relating string theory with F-theory and M-theory. It is shown that when an o

A. De Giovanni, A. Santambrogio, D. Zanon

We consider the N=2 supersymmetric Born-Infeld action and compute one-loop divergences quantizing the theory in N=1 superspace. We find that in the presence of non constant curvature the theory is not renormalizable. The structure of the $(α&#39;)^4$ counterterm, proportional to derivatives of the curvature, is consistent with effective action calculations f

P. Woelfle, K. A. Muttalib

We determine analytically the distribution of conductances of quasi one-dimensional disordered electron systems, neglecting electron-electron interaction, for all strengths of disorder. We find that in the crossover region between the metallic and insulating regimes, P(g) is highly asymmetric, given by ``one-sided'' log-normal distribution. For larger disord

A. G. Akeroyd, A. Arhrib, M. Capdequi Peyranère

We study the associated production of a CP-odd Higgs boson $A^0$ with a neutral gauge boson ($Z$ or photon) in high-energy $e^+ e^-$ collisions at the one-loop level in the framework of Two Higgs Doublet Models (THDM). We find that in the small $\tanβ$ regime the top quark loop contribution is enhanced leading to significant cross-sections (about a few fb),

Naihuan Jing, Kailash Misra, Carla Savage

Basil Gordon, in the sixties, and George Andrews, in the seventies, generalized the Rogers-Ramanujan identities to higher moduli. These identities arise in many areas of mathematics and mathematical physics. One of these areas is representation theory of infinite dimensional Lie algebras, where various known interpretations of these identities have led to in

P. R. A. Campos, J. F. Fontanari, P. F. Stadler

We study analytically the steady-state regime of a network of n error-prone self-replicating templates forming an asymmetric hypercycle and its error tail. We show that the existence of a master template with a higher non-catalyzed self-replicative productivity, a, than the error tail ensures the stability of chains in which m<n-1 templates coexist with the

Valeri V. Dvoeglazov

In the previous paper we proved that the Evans-Vigier definitions of B^{(0)} and {\bf B}^{(3)} may be related {\it not} with magnetic fields but with a 4-vector field. In the present {\it Addendum} it is shown that the terms used in the {\bf B}- Cyclic theorem proposed by M. Evans and J.-P. Vigier may have various transformation properties with respect to Lo

Danielle Morel, J. Piekarewicz

We employ variational Monte Carlo methods to study the transition to strange matter in a simple one-dimensional string-flip model with two flavors and two colors of quarks. The dynamics of the system are described in terms of a many-body potential that confines quarks within hadrons, yet enables the hadrons to separate without generating unphysical long-rang

J. -U. Nabi, H. V. Klapdor-Kleingrothaus

Weak interaction rates and the associated energy losses for massive nuclei in the fp-shell are calculated in stellar matter using a modified form of proton-neutron quasiparticle RPA model with separable Gamow-Teller forces. A total of 209 nuclei with mass numbers ranging from A = 61 to 80 are considered here for the calculation of weak rates. These also incl

N. Kaiser

We analyze the total cross section data for $pp \to ppω$ near threshold measured recently at SATURNE. Using an effective range approximation for the on-shell $pp$ S-wave final state interaction we extract from these data the modulus $|Ω| = 0.53$ fm$^4$ of the threshold transition amplitude $Ω$. We present a calculation of various (tree-level) meson exchange

J. -U Nabi, H. V. Klapdor-Kleingrothaus

Nuclear weak interaction rates for fp-shell nuclei in stellar matter and the associated energy losses are calculated using a modified form of proton-neutron quasiparticle RPA model with separable Gamow-Teller forces. The stellar weak rates are calculated over a wide range of densities (10 < ρY_{e} (gcm^{-3}) < 10^{11}) and temperatures (10^{7} < T(K) < 30 x

Xiaotao Sun

We prove a factorization theorem of generalized functions for moduli spaces of semistable parabolic bundles of any rank.

Riccardo Benedetti, Carlo Petronio

We generalize Turaev&#39;s definition of torsion invariants of pairs $(M,ξ)$, where $M$ is a 3-dimensional manifold and $ξ$ is an Euler structure on $M$ (a non-singular vector field up to homotopy relative to the boundary of $M$ and local modifications in the interior of $M$). Namely, we allow $M$ to have arbitrary boundary and $ξ$ to have simple (convex and

Ken-Ichi Yoshikawa

This is the abstruct of the revised paper. We study the equivariant analytic torsion for K3 surfaces with an anti-symplectic involution with the invariant lattice M (such a surface is called a 2-elementary K3 surface of type M in this paper), and show that it (together with the analytic torsion of the fixed curves) can be identified with the automorphic form

E. Ragoucy

We present a self-contained formulation of the Nonlinear Schrodinger hierarchy and its Yangian symmetry in terms of deformed oscilator algebra (Z.F. algebra). The link between Yangian Y(gl(N)) and finite W(gl(pN),N.gl(p)) algebras is also illustrated in this framework.

R. Banerjee, H. J. Rothe, K. D. Rothe

Using purely Hamiltonian methods we derive a simple differential equation for the generator of the most general local symmetry transformation of a Lagrangian. The restrictions on the gauge parameters found by earlier approaches are easily reproduced from this equation. We also discuss the connection with the purely Lagrangian approach. The general considerat

Anna Ceresole, Gianguido Dall&#39;Agata, Riccardo D&#39;Auria

We give full details for the computation of the Kaluza--Klein mass spectrum of Type IIB Supergravity on AdS_5 x T^{11}, with T^{11}=SU(2)xSU(2)/U(1), that has recently lead to both stringent tests and interesting predictions on the AdS_5/CFT_4 correspondence for N=1 SCFT&#39;s (hep-th/9905226). We exhaustively explain how KK states arrange into SU(2,2|1) sup

Giampiero Esposito, Cosimo Stornaiolo

The quantum theory of a free particle in two dimensions with non-local boundary conditions on a circle is known to lead to surface and bulk states. Such a scheme is here generalized to the quantized Maxwell field, subject to mixed boundary conditions. If the Robin sector is modified by the addition of a pseudo-differential boundary operator, gauge-invariant

Lorenzo Cornalba, Ricardo Schiappa

We conjecture that the Sen-Seiberg limit of the Type IIA D2-brane action in a flat spacetime background can be resummed, at all orders in α&#39;, to define an associative star product on the membrane. This star product can be independently constrained from the equivalent Matrix theory description of the corresponding M2-brane, by carefully analyzing the know

Nima Arkani-Hamed, Savas Dimopoulos, Gia Dvali, Nemanja Kaloper

We construct intersecting brane configurations in Anti-de-Sitter space localizing gravity to the intersection region, with any number $n$ of extra dimensions. This allows us to construct two kinds of theories with infinitely large new dimensions, TeV scale quantum gravity and sub-millimeter deviations from Newton&#39;s Law. The effective 4D Planck scale $M_{

Cheng-Wei Chiang

Upper and lower bounds are established on the Lambda_b -> Lambda_c semileptonic decay form factors by utilizing inclusive heavy-quark-effective-theory sum rules. These bounds are calculated to leading order in Lambda_QCD/m_Q and alpha_s. The O(alpha_s^2 beta_0) corrections to the bounds at zero recoil are also presented. Several form factor models used in th

J. Schechter, H. Weigel

We review the Skyrme model approach which treats baryons as solitons of an effective meson theory. We start out with a historical introduction and a concise discussion of the original two flavor Skyrme model and its interpretation. Then we develop the theme, motivated by the large $N_C$ approximation of QCD, that the {\it effective} Lagrangian of QCD is in f

Y. A. Coutinho, P. P. Queiróz Filho, M. D. Tonasse

The 3-3-1 electroweak model is the simplest chiral extension of the standard model which predicts single and double charged bileptons and exotic quarks carrying -4/3 and 5/3 units of the positron charge. In this paper we study the possibilities of the production and decay of one of these exotic quarks at CERN LEPII-LHC collider. For typical vector bilepton,

Borut Bajc, Goran Senjanovic

It is known that a large neutrino number, of the order of a few percent of the entropy of the universe, leads to symmetry breaking at high temperature. We show here that in the minimal supersymmetric standard model (MSSM) this implies the breaking of electromagnetic charge invariance at T >> M_W allowing for the solution of the monopole problem.

Stephen P. Martin

The effects of supersymmetry breaking are usually parameterized by soft couplings of positive mass dimensions. However, realistic models also predict the existence of suppressed, but non-vanishing, dimensionless supersymmetry-breaking couplings. These couplings are technically hard, but do not lead to disastrous quadratic divergences in scalar masses, and ma

S. Jadach, B. Pietrzyk, E. Tournefier, B. F. L. Ward

The uncertainty in the determination of the Z line-shape parameters coming from the precision of the calculation of the Initial-State Radiation and Initial--Final-State Interference is 2 10**(-4) for the total cross section sigma zero(had) at the Z peak, 0.15 MeV for the Z mass M Z, and 0.1 MeV for the Z width Gamma Z. Corrections to Initial--Final-State Int

D. Bodeker, Guy D. Moore, K. Rummukainen

We develop a discrete lattice implementation of the hard thermal loop effective action by the method of added auxiliary fields. We use the resulting model to measure the sphaleron rate (topological susceptibility) of Yang-Mills theory at weak coupling. Our results give parametric behavior in accord with the arguments of Arnold, Son, and Yaffe, and are in qua

K. Kajantie

This talk will discuss how heavy ion experiments, when moving from SPS (10 + 10 GeV) to RHIC (100+100 GeV) and to LHC (2750+2750 GeV), will enter a new domain of QCD in which the production of even large pT gluons is so abundant that it is simultaneously perturbative but such that the phase space density of gluons is saturated. The saturation scale is estima

J. Blümlein

The status of the twist-2 and the twist-3 integral relations between polarized structure functions in deep inelastic scattering is discussed. The relations can be tested in the upcoming experiments in the range $Q^2 \gsim M_p^2$.

Liu Zhixu, Fu Jinghua, Liu Lianshou

The origin of the erraticity behaviour observed recently in the experiment is studied in some detail. The negative-binomial distribution is used to fit the experimental multiplicity distribution. It is shown that, with the multiplicity distribution taken into account, the experimentally observed erraticity behaviour can be well reproduced using a flat probab

W. Janke, D. Johnston

We report on single-cluster Monte Carlo simulations of the Ising, 4-state Potts and 10-state Potts models on quenched ensembles of planar, tri-valent random graphs. We confirm that the first-order phase transition of the 10-state Potts model on regular 2D lattices is softened by the quenched connectivity disorder represented by the random graphs and that the

M. -P. Lombardo

We explore the phase diagram of SU(2) Lattice Gauge Theory with dynamical fermions in the temperature, mass, chemical potential space. We observe qualitative changes of the dependence of the particle density on $μ$ and $T$, which is compatible with that expected of a gas of free massless quarks $n \propto μ^3$ only for $T \simeq T_c$. At the onset for thermo

Alvaro Montero

A new algorithm for fixing the gauge to (direct) maximal center gauge in SU(N) lattice gauge theory is presented. We check how this method works on SU(3) configurations which are vortex-like, and show how these configurations look like when center projected.

The SLD Collaboration, K. Abe

We present a new preliminary combination of measurements of the parity-violation parameter Ab made by the SLD collaboration using various experimental techniques. The techniques differ in detail, but in general a sample of bb events is selected or enhanced by using the topologically reconstructed mass of the separated vertices formed by decaying B hadrons. T

SELEX Collaboration, S. Y. Jun

We report the first observation of the Cabibbo-suppressed charm baryon decay Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of the decay relative to the Cabibbo-favored Xi_c+ -