October 1998 arXiv papers — page 18

F. Sattin, E. Martines

An analysis of experimental data from the RFX (Reversed Field eXperiment) reversed field pinch machine [L. Fellin, P. Kusstatscher and G. Rostagni, Fusion Eng. Des. {\bf 25}, 315 (1995)] is carried out to investigate the possible existence of deterministic chaos in the edge plasma region. The mathematical tools used include Lyapunov exponents, Kaplan-Yorke d

P. Senger, H. Stroebele

Data on hadronic particle production in symmetric nuclear collisions from SIS/BEVALAC to SPS energies are reviewed. The main emphasis is put on the production of pions, kaons, and antibaryons. Global features will be discussed in terms of rapidity and transverse momentum distributions and the total energy stored in produced particles. Pion and kaon productio

N. Soic, D. Cali, S. Cherubini, E. Costanzo

Spectra of coincident charged particles from the reactions induced by a 52 MeV 7Li beam incident on a beryllium target were measured. Strong contributions of the 7Li quasi-free scattering off the alpha-cluster in 9Be nucleus were observed. This observation supports the conclusions from the study of complete fusion of weakly bound light nuclei at low energies

Luca Molinari

I consider the N-step transfer matrix T for a general block Hamiltonian, with eigenvalue equation L_n ψ_{n+1} + H_n ψ_n + L_{n-1}^\dagger ψ_{n-1} = E ψ_n where H_n and L_n are matrices, and provide its explicit representation in terms of blocks of the resolvent of the Hamiltonian matrix for the system of length N with boundary conditions ψ_0 =ψ_{N+1} =0. I t

A. V. Kitaev, D. A. Korotkin

In this paper we construct explicit solutions and calculate the corresponding $τ$-function to the system of Schlesinger equations describing isomonodromy deformations of $2\times 2$ matrix linear ordinary differential equation whose coefficients are rational functions with poles of the first order; in particular, in the case when the coefficients have four p

A. N. Leznov

The exactly integrable systems connected with semisimple series $A$ for arbitrary grading are presented in explicit form. Their general solutions are expressed in terms of the matrix elements of various fundamental representations of $A_n$ groups. The simplest example of such systems is the generalized Toda chain with the matrices of arbitrary dimensions in

J. E. Avron, A. Elgart

The basic adiabatic theorems of classical and quantum mechanics are over-viewed and an adiabatic theorem in quantum mechanics without a gap condition is described.

Tom Leinster

Notions of `operad' and `multicategory' abound. This work provides a single framework in which many of these various notions can be expressed. Explicitly: given a monad * on a category S, we define the term `(S,*)-multicategory', subject to certain conditions on S and *. Different choices of S and * give some of the existing notions of operad and

F. Bogomolov, Yu. Tschinkel

Let $X$ be an Enriques surface defined over a number field $K$. Then there exists a finite extension $K'/K$ such that the set of $K'$-rational points of $X$ is Zariski dense.

Martin Goldstern, Saharon Shelah

A lattice L is called opc if every monotone function f : L^n -> L is induced by a polynomial. We show here: If L is a lattice with the interpolation property whose cardinality is a strong limit cardinal of uncountable cofinality, then some finite power L^n has an antichain of size kappa. Using our previous result (math.LO/9707203 in the xxx archive) that the

D. Nikshych

We show that indecomposable weak Kac algebras are free over their Cartan subalgebras and prove a duality theorem for their actions. Using this result, for any biconnected weak Kac algebra we construct a minimal action on the hyperfinite II_1 factor. The corresponding crossed product inclusion of II_1 factors has depth 2 and an integer index. Its first relati

Ziv Ran

This paper is a sequel to math.AG/9810041 (whose abstract should have mentioned the fact that a version of the jacobi complex and higher-order Kodaira-Spencer maps were also discovered independently by Esnault and Viehweg). We give a canonical algebraic construction for the variation of Hodge structure associated to the universal m-th order deformation of a

Ivan Cherednik

In the paper, we introduce $q$-deformations of the Riemann zeta function, extend them to the whole complex plane, and establish certain estimates of the number of roots. The construction is based on the recent difference generalization of the Harish-Chandra theory of zonal spherical functions. We also discuss numerical results, which indicate that the locati

B L Feigin, A M Semikhatov

We construct free-field resolutions of unitary representations of the N=2 superconformal algebra. The irreducible representations are singled out from free-field spaces as the cohomology of fermionic screening operators. We construct and evaluate the cohomology of the resolution associated with one fermionic screening (which is related to the representation

I. V. Tyutin, Vadim Zeitlin

The spectrum of collective fermionic excitations in a finite temperature QED_{3+1} is studied in different regimes. It is shown that within the standard perturbation approach the one-loop dispersion equation, besides the ordinary one-particle excitation, has four new solutions. The additional excitations are gauge-dependent and two of them have nonphysical s

J. F. Gomes, F. E. Mendonça da Silveira, G. M. Sotkov, A. H. Zimerman

The algebraic conditions that specific gauged G/H-WZW model have to satisfy in order to give rise to Non-Abelian Toda models with singular metric with or without torsion are found. The classical algebras of symmetries corresponding to grade one rank 2 and 3 singular NA-Toda models are derived.

Chanju Kim

This is an elementary introduction to Wilson renormalization group and continuum effective field theories. We first review the idea of Wilsonian effective theory and derive the flow equation in a form that allows multiple insertion of operators in Green functions. Then, based on this formalism, we prove decoupling and heavy-mass factorization theorems, and d

Yishi Duan, Ying Jiang, Guohong Yang

In the light of $ϕ$-mapping method and topological current theory, the topological structure and the topological quantization of topological linear defects are obtained under the condition that the Jacobian $J(ϕ/v) \neq 0$. When $J(ϕ/v) = 0$, it is shown that there exist the crucial case of branch process. Based on the implicit function theorem and the Taylo

Yishi Duan, Ying Jiang

we present a new topological invariant to describe the space-time defect which is closely related to torsion tensor in Riemann-Cartan manifold. By virtue of the topological current theory and $ϕ$-mapping method, we show that there must exist many strings objects generated from the zero points of $ϕ$-mapping, and these strings are topological quantized and th

Silas R. Beane

We construct an asymptotically free gauge theory with an SU(2)xSU(2)xU(1) vectorlike flavor symmetry. We show that this gauge theory has properties which provide insight into aspects of low-energy QCD.

S. I. Bityukov, N. V. Krasnikov

We investigate χ^{+/-}_1 χ^0_2 pair production at LHC (CMS) with subsequent decays into leptons for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in 3l + no jets + E^{miss}_T events depends rather strongly on the relation between LSP mass χ^0_1 and χ^{+/-}_1 mass.

Cetin Savkli, Franz Gross

Generalizing a covariant framework previously developed, it is shown that confinement insures that meson $\to q+\bar{q}$ decay amplitudes vanish when both quarks are on-shell. Regularization of singularities in a covariant linear potential associated with nonzero energy transfers (i.e. $q^2=0, q^μ\neq0$) is improved.

Graham E. Smye

We investigate the power-suppressed corrections to structure functions in flavour singlet deep inelastic lepton scattering, to complement the previous results for the non-singlet contribution. Our method is a dispersive approach based on an analysis of Feynman graphs containing massive gluons; and our results agree with those obtained from leading infrared r

Michael Spira

The theoretical status of Higgs boson production and decay at the Tevatron within the Standard Model and its minimal supersymmetric extension is reviewed. The focus will be on the evaluation of higher-order corrections to the production cross sections and their phenomenological implications.

Robert Bluhm, Alan Kostelecky, Neil Russell

We present a theoretical analysis of signals for CPT and Lorentz violation in g-2 and charge-to-mass-ratio experiments on electrons and positrons in Penning traps. Experiments measuring anomaly frequencies are found to be the most sensitive to CPT violation. We find that the conventional figure of merit for CPT breaking, involving the difference of the elect

B. R. Webber

The recent results of Forshaw and Sabio Vera on small-$x$ jet rates to order $α_s^3$ are extended to all orders, for any number of jets. A simple generating function is obtained.

Attila Grandpierre

The energy sources of the Sun may actually involve a thermonuclear runaway energy source present in stellar energy producing regions. I consider the conjectures of the derived model for the solar neutrino fluxes in case of a solar core allowed to vary in relation to the surface activity cycle. The observed neutrino flux data suggest a solar core possibly var

Tsutomu Tashiro, Hujio Noda, Kisei Kinoshita, Shin-ichi Nakariki

We discuss the hadroproduction of charmed mesons in the framework of the constituent cascade model taking into account the valence quark annihilation. It is shown that the small valence quark annihilation process dominates the leading particle production at large Feynman x and explains the recent experimental data on the asymmetry between D^0 and D^0 bar at

V. V. Kiselev, A. I. Onishchenko

We present analytical results on the two-loop anomalous dimensions of currents for baryons, containing two heavy quarks $J = [Q^{iT}CΓτQ^j]Γ' q^kε_{ijk}$ with arbitrary Dirac matrices $Γ$ and $Γ'$ in the framework of NRQCD in the leading order over both the relative velocity of heavy quarks and the inverse heavy quark mass. It is shown, that in this

V. Bornyakov, A. Hoferichter, G. Schierholz, A. Thimm

We report new results on the lattice regularization of the chiral Schwinger model and the chiral U(1) model in four dimensions in the CFA.

Attilio Cucchieri

We study the infrared behavior of the gluon propagator in lattice Landau gauge, for pure SU(2) lattice gauge theory in a three-dimensional lattice. Simulations are done for nine different values of the coupling $β$, from $β= 0$ (strong coupling) to $β= 6.0$ (in the weak-coupling region). In the limit of large lattice volumes, we observe in all cases a gluon

Sinya Aoki, Taku Izubuchi, Yoshinobu Kuramashi, Yusuke Taniguchi

We calculate one-loop renormalization factors of bilinear operators made of physical quark fields for domain-wall QCD. We find that finite parts of such renormalization factors have reasonable values at 1-loop except an overlap factor between the physical quark field and the zero mode in the theory. We point out that the 1-loop estimate of overall renormaliz

Robert G. Edwards, Urs M. Heller, Rajamani Narayanan

We use the overlap formalism to define a topological index on the lattice. We study the spectral flow of the hermitian Wilson-Dirac operator and identify zero crossings with topological objects. We determine the topological susceptibility and zero mode size distribution, and we comment on the stability of our results.

C. Adloff

Photoproduction data collected with the H1 detector at HERA in 1994 are used to study the cross-sections for inclusive charged particle production and the structure of the photon. The differential cross-sections dsigma/dpT2, for |eta| < 1 in the HERA laboratory frame, and dsigma/deta for pT > 2 GeV/c and pT > 3 GeV/c have been measured. Model calculations of

Y. Takeuchi, Y. Hemmi, H. Kurashige, Y. Matono

We report on results of an experimental search for the K_L -> pi^+ pi^- e^+ e^- decay mode. We found 13.5 +- 4.0 events and determined its branching ratio to be (4.4 +- 1.3(stat) +- 0.5(syst))*10^{-7}. The result agrees well with the theoretical prediction.

Sukanya Chakrabarti, Adrian P. Gentle, Arkady Kheyfets, Warner A. Miller

Geodesic deviation is the most basic manifestation of the influence of gravitational fields on matter. We investigate geodesic deviation within the framework of Regge calculus, and compare the results with the continuous formulation of general relativity on two different levels. We show that the continuum and simplicial descriptions coincide when the cumulat

David Hochberg, Carmen Molina-Paris, Matt Visser

For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a three-dimensional edgeless achronal spacelike hypersurface of minimal volume. (Zero trace for the extrinsic curvature plus a &#34;flare-out&#34; condition.) This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive

Roberto A. Sussman, Josep Triginer

We derive a new class of exact solutions characterized by the Szekeres-Szafron metrics (of class I), admitting in general no isometries. The source is a fluid with viscosity but zero heat flux (adiabatic but irreversible evolution) whose equilibrium state variables satisfy the equations of state of: (a) ultra-relativistic ideal gas, (b) non-relativistic idea

Maurizio Pizzonia, Giuseppe Di Battista

Applied research in graph algorithms and combinatorial structures needs comprehensive and versatile software libraries. However, the design and the implementation of flexible libraries are challenging activities. Among the other problems involved in such a difficult field, a very special role is played by graph classification issues. We propose new technique

Josh P. Kemp, Zheng Yu Chen

We present a semi-analytical approach to the determination of the dynamic properties of randomly branched polymers under the Rouse approximation. The principle procedure is based on examining a spectrum of eigenvalues which represents the average dynamic behavior of various structures. The calculated spectra show that the eigenvalue distribution is random ev

M. E. Dodd, P. C. Hendry, N. S. Lawson, P. V. E. McClintock

Zurek suggested [Nature 317 (1985) 505] that the Kibble mechanism, through which topological defects such as cosmic strings are believed to have been created in the early Universe, can also result in the formation of topological defects in liquid 4He, i.e. quantised vortices, during rapid quenches through the superfluid transition. Preliminary experiments [H

Alexander Zyuzin

Superfluorescent decay in a weakly disordered slab is considered. By solving the Maxwell-Bloch equations we show, that the cooperation number increases with increasing of the mean free path. Superfluorescent impulse is emitted at a small angle to the slab, isotropically in a plane direction.

C. S. Simoes, J. R. Drugowich de Felicio

We study behaviour of dynamical critical exponents of the two-dimensional Ising model with a line of defects. Simulations done at an early time (first 100 Monte Carlo steps) reveal that the critical exponent of Janssen et al (Z. Phys. B 73 539) depends on the strength of the exchange coupling constant (J&#39;) of the altered line. On the other hand, our simu

Namkyung Lee, D. Thirumalai

The effect of electrostatic interactions on the stretching of DNA is investigated using a simple worm like chain model. In the limit of small force there are large conformational fluctuations which are treated using a self-consistent variational approach. For small values of the external force f, we find theoreticlly and by a simple blob picture that the ext

Torsten Henning, B. Starmark, T. Claeson, P. Delsing

A single electron transistor based on Al-AlO_x-Nb tunnel junctions was fabricated by shadow evaporation and in situ barrier formation. Its output current noise was measured, using a transimpedance amplifier setup, as a function of bias voltage, gain, and temperature, in the frequency range 1...300 Hz. The spot noise at 10 Hz is dominated by a gain dependent

Alexei Vazquez, Oscar Sotolongo-Costa

In the present work we present a fractal model for the beta relaxation in supercooled liquids. The macroscopic dynamics is obtained by superposition of relaxation of independent mesoscopic regions (cages). Scaling relations and exponents are assumed for the distribution of cage sizes and for the size dependent response of the independent cages. In this way w

Mu-Yong Choi, J. S. Kim

We have studied the thermopower of La_2CuO_{4+z} and Nd_2CuO_{4-y} which undergo an antiferromagnetic transition near room temperature and Bi_2Sr_{2-x}La_xCuO_{6+z} for which a broad spectrum of doping is possible. The thermopower of La_2CuO_{4+z} and Nd_2CuO_{4-y} is seen to exhibit an anomaly at the Neel temperature, whereas the resistivity is not. The ext

Klaus Kirsten, David J. Toms

We discuss the phenomenon of Bose-Einstein condensation of an ideal non-relativistic Bose gas in an arbitrarily shaped cavity. The influence of the finite extension of the cavity on all thermodynamical quantities, especially on the critical temperature of the system, is considered. We use two main methods which are shown to be equivalent. The first deals wit

Anusha Hazareesing, Jean-Philippe Bouchaud

Emig and Nattermann (Phys. Rev. Lett. 81, 1469 (1998)) have recently investigated the competition between lattice pinning and impurity pinning using a Renormalisation Group (RG) approach. For elastic objects of internal dimensions $2 < D < 4$, they find, at zero temperature, an interesting second order phase transition between a flat phase for small disorder

C E Creffield, Wolfgang Haeusler, J H Jefferson, Sarben Sarkar

The low-lying eigenstates of a system of two electrons confined within a two-dimensional quantum dot with a hard polygonal boundary are obtained by means of exact diagonalization. The transition from a weakly correlated charge distribution for small dots to a strongly correlated &#34;Wigner molecule&#34; for large dots is studied, and the behaviour at the cr

B. Jouault, G. Faini, A. Angelucci, M. Di Stasio

We report on non-linear magneto-tunneling experiments carried out in single GaAs vertical quantum dots. We show that conduction at low voltage bias can be a spectroscopic tool for both the ground state and first excited states of few electrons on the dot. Increasing voltage a large resonant peak is observed and attributed to tunneling across the quasi-contin

Martin Andersson, Magnus Boman, Stellan Ostlund

We investigate convergence of the density matrix renormalization group (DMRG) in the thermodynamic limit for gapless systems. Although the DMRG correlations always decay exponentially in the thermodynamic limit, the correlation length at the DMRG fixed-point scales as $ξ\sim m^{1.3}$, where $m$ is the number of kept states, indicating the existence of algebr

S. Gluzman, V. I. Yukalov

Sharp changes in time series representing market dynamics are studied by means of the self--similar analysis suggested earlier by the authors. These sharp changes are market booms and crashes. Such crises phenomena in markets are analogous to critical phenomena in physics. A simple classification of the market crisis phenomena is given.

M. Serva

A portfolio of different stocks and a risk-less security whose composition is dynamically maintained stable by trading shares at any time step leads to a growth of the capital with a nonrandom rate. This is the key for the theory of optimal-growth investment formulated by Kelly. In presence of transaction costs, the optimal composition changes and, more impo

V. Cataudella

The critical behaviour of the Fully Frustrated XY model in presence of weak positional disorder is studied in a square lattice by Monte Carlo methods. The critical exponent associated to the divergence of the chiral correlation length is found to be equal to 1.7 already at very small values of disorder. Furthermore the helicity modulus jump is found larger t

Karl-Peter Marzlin, Weiping Zhang

We study the interaction of a Bose-Einstein condensate, which is confined in an optical lattice, with a largely detuned light field propagating through the condensate. If the condensate is in its ground state it acts as a periodic dielectric and gives rise to photonic band gaps at optical frequencies. The band structure of the combined system of condensed la

Sorin Bastea

It has been known for a long time that the ground state problem of random magnets, e.g. random field Ising model (RFIM), can be mapped onto the max-flow/min-cut problem of transportation networks. I build on this approach, relying on the concept of residual graph, and design an algorithm that I prove to be exact for finding all the minimum cuts, i.e. the gro

Sorin Bastea, Philip M. Duxbury

Using exact optimization methods, we find all of the ground states of +/- h random-field Ising magnets (RFIM) and of dilute antiferromagnets in a field (DAFF). The degenerate ground states are usually composed of isolated clusters (two-level systems) embedded in a frozen background. We calculate the paramagnetic response (sublattice response) and the ground

J. Edelstein, W. V. Dixon, E. Korpela

Galmatheia is a broad bandpass (900-1800 Angstrom), far-ultraviolet (FUV) nebular spectrograph (lambda /delta lambda ~ 650) for the study of the evolution of galactic plasma with a temperature of 10^4.5 - 10^6 K. Galmatheia will survey the FUV sky with 5&#39; imaging and conduct hundreds of deep 8 degree x 5&#39; field pointings during its proposed two-year

K. J. Fricke, P. Papaderos

We have used ROSAT PSPC and HRI to study the properties of the soft X-ray emission in a sample of colliding starburst galaxies. Together with data from other spectral ranges (optical, radio and FIR) we investigate the emergence of soft X-ray emission during progressive stages of interaction and merging.

Xin-Min Hua, Demosthenes Kazanas, Wei Cui

We exhibit, by compiling all data sets we can acquire, that the Fourier frequency dependent hard X-ray lags, first observed in the analysis of aperiodic variability of the light curves of the black hole candidate Cygnus X-1, appear to be a property shared by several other accreting black hole candidate sources and also by the different spectral states of thi

David H. Weinberg, Scott Burles, Rupert A. C. Croft, Romeel Dave&#39;

We outline the physical picture of the high-redshift Ly-alpha forest that has emerged from cosmological simulations, describe statistical characteristics of the forest that can be used to test theories of structure formation, present a preliminary comparison between simulation results and measurements from Keck HIRES spectra, and discuss a recent determinati

Tomasz Bulik, Dorota Gondek-Rosinska, Wlodzimierz Kluzniak

The kilohertz quasi periodic oscillations (QPOs) discovered in several low mass X-ray binaries (LMXBs) by the Rossi X-ray Timing Explorer (XTE) are thought to occur at the orbital frequency in accretion discs whose inner edge corresponds to the innermost (marginally) stable orbit allowed by general relativity. These ideas have been applied to constrain the e

K. Pottschmidt, J. Wilms, M. A. Nowak, J. B. Dove

We present results from a 20 ksec RXTE observation of the black hole candidate Cyg X-1. We apply self-consistent accretion disk corona models to these hard state data and show that Comptonization in a spherical corona irradiated by soft photons from an exterior cold disk is able to successfully model the spectrum. We also present the power spectrum, the cohe

Tadayuki Kodama, Richard G. Bower, Eric F. Bell

We present the rest-frame colour-magnitude diagram for 35 early-type galaxies in the Hubble Deep Field with median redshift 0.9. Although with considerable scatter, a red sequence well-described by the passive evolution of an intrinsically old stellar population is observed. Comparison with the passively evolved colour-magnitude relation of the rich Coma clu

A. Loinger

The gravitational waves are non-physical sinuosities generated, in the last analysis, by undulating reference frames.

Eliot Quataert, Ramesh Narayan

We calculate spectral models of advection-dominated accretion flows, taking into account the possibility that significant mass may be lost to a wind. We apply the models to the soft X-ray transient V404 Cyg in quiescence and the Galactic center source Sgr A*. We show that there are qualitative degeneracies between the mass loss rate in the wind and parameter

S. Arnouts, S. D&#39;Odorico, S. Cristiani, S. Zaggia

We present a deep BVrI multicolor catalog of galaxies in a 5.62 sq.arcmin field 80 arcsec south of the high redshift (z=4.7) quasar BR 1202-0725, derived from observations with the direct CCD camera SUSI at the ESO NTT. The formal 5$σ$ magnitude limits (in 2 x FWHM apertures) are 26.9, 26.5, 25.9 and 25.3 in B, V, r and I respectively. Counts, colors for the

G. L. H. Harris, W. E. Harris, G. B. Poole

The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a sample of 10,000 red giant stars in the outer halo of the giant elliptical NGC 5128. Comparison with the fiducial RGBs of Milky Way globular clusters and model isochrones demonstrates that this outer-halo population is completely dominated by old stars, with an extremely broad me

Jon Loveday

We present preliminary measurements of the b_J and K-band luminosity functions (LFs) of field galaxies obtained from optical and K-band imaging of a sample of galaxies selected from the Stromlo-APM Redshift Survey. The b_J LF is consistent with that previously published from photographic data. The K-band LF has been estimated over a range of 12 magnitudes an

Jon Loveday

The Sloan Digital Sky Survey (SDSS) will carry out a digital photometric and spectroscopic survey over pi steradians in the northern Galactic cap. An array of CCD detectors used in drift-scan mode will image the sky in five passbands to a limiting magnitude of r&#39; ~ 23. Selected from the imaging survey, 10^6 galaxies, 10^5 quasars and selected samples of

M. Molla, E. Hardy, D. Beauchamp

The radial distributions of the Mg2 and Fe5270 Lick spectral indices have been measured to large radial distances on the disks of NGC 4303 and NGC 4535 using an imaging technique based on interference filters. These data, added to those of NGC 4321 previously published in Paper I of this series are used to constraint chemical (multiphase) evolutionary models

Gert Brodin, Mattias Marklund

We consider the parametric excitation of a Langmuir wave and an electromagnetic wave by gravitational radiation, in a thin plasma on a Minkowski background. We calculate the coupling coefficients starting from a kinetic description, and the growth rate of the instability is found. The Manley-Rowe relations are fulfilled only in the limit of a cold plasma. As

S. M. Croom, T. Shanks, B. J. Boyle, R. J. Smith

We present preliminary results from the 2-degree Field (2dF) QSO Redshift Survey currently under way at the Anglo-Australian Telescope. This survey aims to determine the redshifts of >25000 QSOs over a redshift range of 0.3<z<3.0 with the primary goal of investigating large-scale structure in the Universe to high redshift and at very large scales (~1000h-1Mp

S. Zhang, T. P. Li, M. Wu

With a direct demodulation method, we have reanalyzed the data from COMPTEL/CGRO observation of PKS0528+134 during the 1993 March flare in gamma-rays. Our results show that during the flare gamma-rays were detected at a level approximately 2.4-3.8 times greater than the observed intensity in two earlier COMPTEL observations VP 0 and VP 1 in the energy range

F. Matteucci, D. Romano, P. Molaro

The chemical evolution of the Galactic bulge is treated here in the context of an inside-out model for the Galaxy formation. We assume that this central region evolved even faster than the Galactic halo and test the effect of changing the slope of the IMF on the predicted stellar metallicity distribution for bulge stars. An IMF favoring the formation of mass

A. N. Lasenby, C. J. L. Doran, M. P. Hobson, Y. Dabrowski

A new method is proposed for modelling spherically symmetric inhomogeneities in the Universe. The inhomogeneities have finite size and are compensated, so they do not exert any measurable gravitational force beyond their boundary. The region exterior to the perturbation is represented by a Friedmann-Robertson-Walker (FRW) Universe, which we use to study the

Y. X. Feng, T. P. Li, L. Chen

X-ray shots of Cyg X-1 in different energy bands and spectral states have been studied with PCA/RXTE observations. The detailed shot structure is obtained by superposing many shots with one millisecond time bin through aligning their peaks with an improved algorithm. In general, the shots are composed of a slow rise and fast decay. The shot structures in the

V. Barger, J. G. Learned, S. Pakvasa, T. J. Weiler

We show that the observed zenith angle dependence of the atmospheric neutrinos can be accounted for by neutrino decay. Furthermore, it is possible to account for all neutrino anomalies with just three flavors.

B. T. Soifer, G. Neugebauer, K. Matthews, E. E. Becklin

Images of Arp 220 from 3.45 to 24.5 $μ$m with 0.5&#39;&#39; resolution are presented which clearly separate the nucleus into at least two components. The western component is about three times more luminous than the eastern component, but the silicate absorption in the fainter, eastern component is roughly 50% greater than the absorption in the western compo

Patricia M. Knezek, Kenneth R. Sembach, John S. Gallagher, III

We present deep B, R and Halpha imaging of 3 dwarf galaxies: NGC3377A, NGC4286, and IC3475. Based on previous broadband imaging and HI studies, these mixed-morphology galaxies were proposed by Sandage & Hoffman (1991) to be, respectively, a gas-rich low surface brightness Im dwarf, a nucleated dwarf that has lost most of its gas and is in transition from Im

Matt Visser, Bruce Bassett, Stefano Liberati

We argue that ``effective&#39;&#39; superluminal travel, potentially caused by the tipping over of light cones in Einstein gravity, is always associated with violations of the null energy condition (NEC). This is most easily seen by working perturbatively around Minkowski spacetime, where we use linearized Einstein gravity to show that the NEC forces the lig

S. Ostlund

This letter discusses the Landau Ginzburg theory of a Josephson junction composed of on one side a pure d-wave superconductor oriented with the $(110)$ axis normal to the junction and on the other side either s-wave or d-wave oriented with $(100)$ normal to the junction. We use simple symmetry arguments to show that the Josephson current as a function of the

M. V. Babich, D. A. Korotkin

We simplify Hitchin's description of SU(2)-invariant self-dual Einstein metrics, making use of the tau-function of related four-pole Schlesinger system.

G. Krein, A. W. Thomas, K. Tsushima

The mean field description of nuclear matter in the quark-meson coupling model is improved by the inclusion of exchange contributions (Fock terms). The inclusion of Fock terms allows us to explore the momentum dependence of meson-nucleon vertices and the role of pionic degrees of freedom in matter. It is found that the Fock terms maintain the previous predic

T. Montaruli

MACRO can detect three topologies of neutrino induced events, corresponding to different parent neutrino energies. The most numerous sample is made of upward throughgoing muons induced by atmospheric neutrinos of average energy 100 GeV. We have observed less events than expected events and the observed zenith distribution does not fit the expected one in the

Karim Benakli, Sacha Davidson

We make generic remarks about baryogenesis in models where the scale $M_s$ of quantum gravity is much below the Planck scale. These correspond to M-theory vacua with a large volume for the internal space. Baryogenesis is a challenge, particularly for $M_s \lappeq 10^5$ GeV, because there is an upper bound on the reheat temperature of the Universe, and becaus

D. R. Phillips, S. R. Beane, M. C. Birse

We consider the most general loop integral that appears in non-relativistic effective field theories with no light particles. The divergences of this integral are in correspondence with simple poles in the space of complex space-time dimensions. Integrals related to the original integral by subtraction of one or more poles in dimensions other than D=4 lead t

A. Patkos, Zs. Szep

The classical kinetic theory of one-component self-interacting scalar fields is formulated in the broken symmetry phase and applied to the phenomenon of Landau damping. The domain of validity of the classical approach is found by comparing with the result of a 1-loop quantum calculation.

Maciej Kuna, Marek Czachor, Sergiej B. Leble

Generalized Euler-Arnold-von Neumann density matrix equations can be solved by a binary Darboux transformation given here in a new form: $ρ[1]=e^{P\ln(μ/ν)}ρe^{-P\ln(μ/ν)}$ where $P=P^2$ is explicitly constructed in terms of conjugated Lax pairs, and $μ$, $ν$ are complex. As a result spectra of $ρ$ and $ρ[1]$ are identical. Transformations allowing to shift

Stefano Mancini, David Vitali, Paolo Tombesi

We propose a feedback scheme to control the vibrational motion of a single trapped particle based on indirect measurements of its position. It results the possibility of a motional phase space uncertainty contraction, correponding to cool the particle close to the motional ground state.

The NA49 Collaboration, H. Appelshauser et al

We report measurements of Xi and Xi-bar hyperon absolute yields as a function of rapidity in 158 GeV/c Pb+Pb collisions. At midrapidity, dN/dy = 2.29 +/- 0.12 for Xi, and 0.52 +/- 0.05 for Xi-bar, leading to the ratio of Xi-bar/Xi = 0.23 +/- 0.03. Inverse slope parameters fitted to the measured transverse mass spectra are of the order of 300 MeV near mid-rap

Nguyen Tuan Anh, Nguyen Anh Ky, Hoang Ngoc Long

The mass spectrum and the eigenstates of the Higgs sector of the minimal 3 3 1 model are revisited in detail. There are discrepancies between our results and previous results by another author.

A. V. Belitsky, D. Müller, L. Niedermeier, A. Schäfer

We present a general method for the solution of the renormalization group equations for the non-forward parton distributions on the two-loop level in the flavour singlet channel based on an orthogonal polynomial reconstruction. Using this formalism we study the effects of the evolution on recently proposed model distribution functions.

D. Downes, R. Neri, T. Wiklind, D. J. Wilner

We detected with the IRAM interferometer the lines of CO(4-3) and CO(9-8) from the recently-discovered broad absorption line quasar APM 08279+5255. The molecular lines are at a redshift of 3.911, which we take to be the true cosmological redshift of the quasar&#39;s host galaxy. This means the quasar emission lines at z=3.87 are blueshifted by a kinematic co

A. N. Baushev, G. S. Bisnovatyi-Kogan

The spectrum of cyclotron radiation is calculated for anisotropically distributed relativistic electrons with a nonrelativistic velocity scattering across the magnetic field. It is shown that if such electrons are responsible for a formation of the &#34;cyclotron&#34; line in the spectrum of Her X-1, then the value of its magnetic field $(3-6)\cdot 10^{10}$

M. Ciuchini, R. Contino, E. Franco, G. Martinelli

We reanalyze B -> D pi and B -> K J/psi data to extract a set of parameters which give the relevant hadronic matrix elements in terms of factorized amplitudes. Various sources of theoretical uncertainties are studied, in particular those depending on the model adopted for the form factors. We find that the fit to the B -> D pi branching ratios substantially

U. Frisch, A. Mazzino, A. Noullez, M. Vergassola

A Lagrangian method is introduced for calculating simultaneous n-point correlations of a passive scalar advected by a random velocity field, with random forcing and finite molecular diffusivity kappa. The method, which is here presented in detail, is particularly well suited for studying the kappa tending to 0 limit when the velocity field is not smooth. Eff

T. Hatsuda, T. Kunihiro, H. Shimizu

Spectral enhancement near the 2m_π threshold in the I=J=0 channel in nuclei is shown to be a distinct signal of the partial restoration of chiral symmetry. The relevance of this phenomenon with the possible detection of 2π^{0} and 2γin hadron-nucleus and photo-nucleus reactions is discussed.

Steen Hannestad

The formation of the cosmic microwave background radiation (CMBR) provides a very powerful probe of the early universe at the epoch of recombination. Specifically, it is possible to constrain the variation of fundamental physical constants in the early universe. We have calculated the effect of a varying electromagnetic coupling constant (α) on the CMBR and