February 2002 arXiv papers — page 13

Brahim Lamine, Marc-Thierry Jaekel, Serge Reynaud

We study the decoherence of atomic interferometers due to the scattering of stochastic gravitational waves. We evaluate the `direct' gravitational effect registered by the phase of the matter waves as well as the `indirect' effect registered by the light waves used as beam-splitters and mirrors for the matter waves. Considering as an example the spac

G. Labeyrie, C. Miniatura, C. A. Mueller, O. Sigwarth

We study the shape of the coherent backscattering (CBS) cone obtained when resonant light illuminates a thick cloud of laser-cooled rubidium atoms in presence of a homogenous magnetic field. We observe new magnetic field-dependent anisotropies in the CBS signal. We show that the observed behavior is due to the modification of the atomic radiation pattern by

Ernst Karl Kunst

Astrophysical models developed to explain superluminal motion in beaming phenomena are shown to be incomplete and the correct kinematical expression in any case to predict projected velocities slower than the speed of light. The observed superluminal motions in the plane of the sky are proposed to be real.

Masato Ida

Transition frequencies of two spherical gas bubbles interacting in an acoustic field are discussed theoretically. In the present study, transition frequency is defined as the frequency of external sound for which the phase difference between a bubble's pulsation and the external sound is $π/ 2$. It is shown by a linear theory that a bubble interacting wi

Jurgen Schaffner-Bielich, Dima Kharzeev, Larry McLerran, Raju Venugopalan

Motivated from the formation of an initial state of gluon-saturated matter, we discuss scaling relations for the transverse mass spectra at BNL's Relativistic Heavy-Ion Collider (RHIC). We show on linear plots, that the transverse mass spectra for various hadrons can be described by an universal function. The transverse mass spectra for different central

B. Funke Haas, T. Frederico, B. V. Carlson, F. B. Guimarães

Using the Dirac-Hartree-Fock-Bogoliubov approximation to study nuclear pairing, we have found the short-range correlations of the Dirac $^1$S$_0$ pairing fields to be essentially identical to those of the two-nucleon virtual state at all values of the baryon density. We make use of this fact to develop a relativistic separable potential that correctly descri

K. Gallmeister, C. Greiner, Z. Xu

In the context of the `jet quenching' phenomena typically materialization of the jet is assumed to take place in vacuum outside the reaction zone. On the other hand quantum mechanical estimates give a hadronization time on the order of only a few fm/c for jets materializing into hadrons with transverse momenta of $\pT{} \leq 10 GeV$, which thus should we

K. Amos, S. Karataglidis

Neutron total reaction cross sections at 45, 50, 55, 60, 65, and 75 MeV from nuclei 12C, 28Si, 56Fe, 90Zr, and 208Pb have been measured and are compared with (microscopic) optical model predictions. The optical potentials were obtained in coordinate space by full folding effective nucleon-nucleon interactions with realistic nuclear ground state density matri

M. F. M. Lutz, B. Friman, M. Soyeur

The study of the $πN\to ρ^0 N$ and $πN \to ωN$ amplitudes below and close to the vector meson production threshold ($1.4<\sqrt s <1.8$ GeV)reveals a rich structure arising from the presence of baryon resonances in this energy range. These resonances are reflected in the interference pattern of the $e^+e^-$ decays of the $ρ^0$- and $ω$-mesons produced in $π^-

J. Dukelsky, S. Pittel, S. S. Dimitrova, M. V. Stoitsov

The particle-hole Density Matrix Renormalization Group (p-h DMRG) method is discussed as a possible new approach to large-scale nuclear shell-model calculations. Following a general description of the method, we apply it to a class of problems involving many identical nucleons constrained to move in a single large j-shell and to interact via a pairing plus q

K. Reygers

Transverse momentum spectra for neutral pions have been measured by the WA98 experiment in sqrt{s_{nn}}=17.3 GeV Pb+Pb collisions at the CERN SPS and by the PHENIX experiment in sqrt{s_{nn}}=130 GeV Au+Au collisions at RHIC. The neutral pion yields in central collisions for both reaction systems are compared to scaled transverse momentum spectra for nucleon-

A. Devismes

Heavy ion collisions at SIS energies (1-2 AGeV) offer an unique tool to probe the properties of hot and dense nuclear matter. In particular, the partial restoration of chiral symmetry is predicted to lead in this energy range to in-medium modifications of hadron properties. Strange particle production below or close to the threshold energy is a useful probe

Sasanka Ghosh, Debojit Sarma

The N=2 supersymmetric KdV equation of Inami and Kanno is bilinearized employing the Hirota method and the existence of $N$ soliton solutions is demonstrated. The exact form of the solutions are explicitly obtained and an interesting symmetry of the equations of motion is observed.

Sasanka Ghosh, Debojit Sarma

Two different types of N=1 modified KdV equations are shown to possess $N$ soliton solutions. The soliton solutions of these equations are obtained by casting the equations in the bilinear forms using the supersymmetric extension of the Hirota method. The distinguishing features of the soliton solutions of N=1 mKdV and N=1 mKdV B equations are discussed.

Sebastien Gouezel

We generalize a method developed by Sarig to obtain polynomial lower bounds for correlation functions for maps with a countable Markov partition. A consequence is that LS Young&#39;s estimates on towers are always optimal. Moreover, we show that, for functions with zero average, the decay rate is better, gaining a factor 1/n. This implies a Central Limit The

G. M. Coclite, B. Piccoli

This paper is concerned with a fluidodynamic model for traffic flow. More precisely, we consider a single conservation law, deduced from conservation of the number of cars, defined on a road network that is a collection of roads with junctions. The evolution problem is underdetermined at junctions, hence we choose to have some fixed rules for the distributio

Anatoly N. Kochubei

Let $V$ be a projective limit, with respect to the renormalized norm mappings, of the groups of principal units corresponding to a strictly increasing sequence of finite separable totally and tamely ramified Galois extensions of a local field. We study the structure of the dual group $V&#39;$, introduce and investigate a fractional differentiation operator o

Mihai Tibar

We present several aspects of the &#34;topology of meromorphic functions&#34;, which we conceive as a general theory which includes the topology of holomorphic functions, the topology of pencils on quasi-projective spaces and the topology of polynomial functions.

S. R. Gal

A closed form formula (generating function) for the Euler characteristic of the configuration space of $\scriptstyle n$ particles in a simplicial complex is given.

Georges Racinet

The values at positive integers of the polyzeta functions are solutions of the polynomial equations arising from Drinfeld&#39;s associators, which have numerous applications in quantum algebra. Considered as iterated integrals they become periods of the motivic fundamental groupoid of $\mathbb{P}^1\setminus\{0,1,\infty\}$. From there comes a fundamental, yet

N. A. Daurtseva, N. K. Smolentsev

The space ${\mathcal A}$ of almost complex structures on a closed manifold $M$ is studied. A natural parametrization of the space ${\mathcal A}$ is defined. It is shown, that ${\mathcal A}$ is a infinite dimensional complex weak Pseudo-Riemannian manifold. A curvature of the space ${\mathcal A}$ is found. The space ${\mathcal A}_ω$ of associated almost compl

Scott Ness, George Siopsis

We discuss the quantization of a scalar particle moving in two-dimensional de Sitter space. We construct the conformal quantum mechanical model on the asymptotic boundary of de Sitter space in the infinite past. We obtain explicit expressions for the generators of the conformal group and calculate the eigenvalues of the Hamiltonian. We also show that two-poi

A. Agarwal, S. G. Rajeev

The equations of motion of quantum Yang - Mills theory (in the planar `large N&#39; limit), when formulated in Loop-space are shown to have an anomalous term, which makes them analogous to the equations of motion of WZW models. The anomaly is the Jacobian of the change of variables from the usual ones i.e. the connection one form $A $, to the holonomy $U$. A

I. Fruhwirth, J. M. Grimstrup, Z. Morsli, L. Popp

We discuss $θ$-deformed Maxwell theory at first order in $θ$ with the help of the Seiberg-Witten (SW) map. With an appropriate field redefinition consistent with the SW-map we analyse the one-loop corrections of the vacuum polarization of photons. We show that the radiative corrections obtained in a previous work may be described by the Ward-identity of the

T. Barnes

This contribution reviews some of the theoretical issues and predictions that were discussed at HADRON2001. The topics are divided into principle areas, 1) exotics, 2) vectors, 3) scalars, and 4) higher-mass states. The current status of theoretical predictions for each area are summarized, together with a brief description of experiment. New and detailed ex

Gordon L. Kane, Lian-Tao Wang, Ting T. Wang

We explore several supersymmetric alternatives to explain predictions for the cosmic ray positron excess. Light sneutrino or neutralino LSP&#39;s, and a fine-tuned model designed to provide a delta-function input, can give adequate statistical descriptions of the reported HEAT data if non-thermal production of the relic cold dark matter density dominates and

Mariana Frank, Shuquan Nie

The rare decay $b \to s γ$ is studied in the left-right supersymmetric model. We give explicit expressions for all the amplitudes associated with the supersymmetric contributions coming from gluinos, charginos and neutralinos in the model to one-loop level. The branching ratio is enhanced significantly compared to the standard model and minimal supersymmetri

A. V. Belitsky, T. D. Cohen

An analysis of the baryon-baryon potential from the point of view of large-N(c) QCD is performed. A comparison is made between the N(c)-scaling behavior directly obtained from an analysis at the quark-gluon level to the N(c)-scaling of the potential for a generic hadronic field theory in which it arises via meson exchanges and for which the parameters of the

M. Hirsch, W. Porod, M. A. Diaz, J. C. Romao

The simplest unified extension of the Minimal Supersymmetric Standard Model with bilinear R-Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies. Despite the smallness of neutrino masses R-parity violation is observable at present and future high-energy colliders, provid

M. van Iersel, B. L. G. Bakker, F. Pijlman

We calculated bound states in the quantum field theoretical approach. Using the Wick-Cutkosky model and an extended version of this model (in which a particle with finite mass is exchanged) we have calculated the bound states in the scalar case.

Elvio Di Salvo

We shortly review the various methods suggested for determining the transversity function. Among such methods, we consider especially those based on semi-inclusive deep inelastic scattering. In the framework of this kind of reactions, we propose to measure a double spin asymmetry, using a transversely polarized proton target and a longitudinally polarized le

Dennis D. Dietrich, Gouranga C. Nayak, Walter Greiner

We discuss the production mechanism of partons via vacuum polarization during the very early, gluon dominated phase of an ultrarelativistic heavy-ion collision in the framework of the background field method of quantum chromodynamics.

Naoyuki Haba, Tomoharu Suzuki

Recently the evidence of the neutrinoless double $β$ ($0νββ$) decay has been announced. This means that neutrinos are Majorana particles and their mass hierarchy is forced to certain patterns in the diagonal basis of charged lepton mass matrix. We estimate the magnitude of $0νββ$ decay in the classification of the neutrino mass hierarchy patterns as Type A,

Prem P. Srivastava, Stanley J. Brodsky

Light-front (LF) quantization in light-cone (LC) gauge is used to construct a unitary and simultaneously renormalizable theory of the Standard Model. The framework derived earlier for QCD is extended to the Glashow, Weinberg, and Salam (GWS) model of electroweak interaction theory. The Lorentz condition is automatically satisfied in LF-quantized QCD in the L

Rudolph C. Hwa, C. B. Yang

The parton distribution functions determined by CTEQ at low $Q^2$ are used as inputs to test the validity of the valon model. The valon distributions in a nucleon are first found to be nearly $Q$ independent. The parton distribution in a valon are shown to be consistent with being universal, independent of the valon type. The momentum fractions of the parton

S. Khalil, C. Munoz, E. Torrente-Lujan

We analyse the relic neutralino density in supersymmetric models with an intermediate unification scale. In particular, we present concrete cosmological scenarios where the reheating temperature is as small as $\cal{O}$ $1 - 1000$ MeV). When this temperature is associated to the decay of moduli fields producing neutralinos, we show that the relic abundance i

I. F. Ginzburg, M. V. Vychugin

1. Discussing 2HDM and Higgs potential, we find the parameters range giving naturally weak effects of CP violation and Flavor Changing Neutral Currents. Within this approach, the widely discussed decoupling limit with heavy $H^\pm$, $H$ and $A$ corresponds to an unnatural set of 2HDM parameters. 2. We define the SM--like scenario as that in which after LHC a

A. Hasenfratz, F. Knechtli

We study the finite temperature phase transition of four and two flavor staggered fermions with hypercubic smeared link actions. These preliminary studies suggest that the improved flavor symmetry of the fermionic action can have a significant effect on the finite temperature phase diagram.

Chris Allton

Recent results from the UKQCD Collaboration&#39;s dynamical simulations are presented. The main feature of these ensembles is that they have a fixed lattice spacing and volume, but varying sea quark mass from infinite (corresponding to the quenched simulation) down to roughly that of the strange quark mass. The main aim of this work is to uncover dynamical q

S. B. Athar, CLEO Collaboration

The ratio of charged and neutral B meson production at the Upsilon(4S), f_{+-}/f_{00}, is measured through the decays B bar -> D* l- nu_l bar, reconstructed using a partial reconstruction method where the D* is detected only through a pion daughter from the decay D* -> D pi. Using data collected by the CLEO II detector, the charged and neutral B decays are m

Joel A. Smoller

We consider the interaction of gravity, as expressed by Einstein&#39;s Equations of General Relativity, to other force fields. We describe some recent results, discussing both the mathematics, and the physical interpretations. These results concern both elementary particles, as well as cosmological models. (This paper describes joint work variously done with

A. K. Raychaudhuri

The paper establishes the result that solutions of the type described in the title of the article are only those that have been already presented in the literature. The procedure adopted in the paper is somewhat novel - while the usual practice is to display an exact solution and then to examine whether it is singularity free, the present paper discovers the

Sergey S. Kokarev

Gravity is treated as manifestation of bending of 4D plate at the variational functionals level. Some estimates of elastic constants of space-time are made. Field lagrangians and Einstein equations are discussed in view point of the approach.

Daniel Lehmann, Liadan Ita O&#39;Callaghan, Yoav Shoham

Some important classical mechanisms considered in Microeconomics and Game Theory require the solution of a difficult optimization problem. This is true of mechanisms for combinatorial auctions, which have in recent years assumed practical importance, and in particular of the gold standard for combinatorial auctions, the Generalized Vickrey Auction (GVA). Tra

Rica Gonen, Daniel Lehmann

Previous works suggested the use of Branch and Bound techniques for finding the optimal allocation in (multi-unit) combinatorial auctions. They remarked that Linear Programming could provide a good upper-bound to the optimal allocation, but they went on using lighter and less tight upper-bound heuristics, on the ground that LP was too time-consuming to be us

I. A. Merkulov, Al. L. Efros, M. Rosen

We have studied theoretically the electron spin relaxation in semiconductor quantum dots via interaction with nuclear spins. The relaxation is shown to be determined by three processes: (i) -- the precession of the electron spin in the hyperfine field of the frozen fluctuation of the nuclear spins; (ii) -- the precession of the nuclear spins in the hyperfine

Juan R. Sanchez

A new model for stocks markets using integer values for each stock price is presented. In contrast with previously reported models, the variables used in the model are not of binary type, but of more general integer type. It is shown how the behavior of the noisy and fundamentalists traders can be taken into account simultaneously in the time evolution of ea

C. Pennetta, L. Reggiani, Gy. Trefán, E. Alfinito

We consider a two-dimensional random resistor network (RRN) in the presence of two competing biased percolations consisting of the breaking and recovering of elementary resistors. These two processes are driven by the joint effects of an electrical bias and of the heat exchange with a thermal bath. The electrical bias is set up by applying a constant voltage

Umberto Marini Bettolo Marconi, Andrea Puglisi

We investigate a Maxwell model of inelastic granular mixture under the influence of a stochastic driving and obtain its steady state properties in the context of classical kinetic theory. The model is studied analytically by computing the moments up to the eighth order and approximating the distributions by means of a Sonine polynomial expansion method. The

Kenji Hirose, Ned S. Wingreen

We investigate the ground-state energy and spin of disordered quantum dots using spin-density-functional theory. Fluctuations of addition energies (Coulomb-blockade peak spacings) do not scale with average addition energy but remain proportional to level spacing. With increasing interaction strength, the even-odd alternation of addition energies disappears,

Axel Arnold, Christian Holm

We present a new method, in the following called MMM2D, to accurately calculate the electrostatic energy and forces on charges being distributed in a two dimensional periodic array of finite thickness. It is not based on an Ewald summation method and as such does not require any fine-tuning of an Ewald parameter for convergence. We transform the Coulomb sum

P. Levy, F. Parisi, L. Granja, E. Indelicato

The time dependent response of the magnetic and transport properties of Fe-doped phase separated (PS) manganite La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ is reported. The nontrivial coexistence of ferromagnetic (FM) and non FM regions induces a slow dynamics which leads to time relaxation and cooling rate dependence within the PS regime. This dynamics influences drastic

P. Levy, F. Parisi, M. Quintero, L. Granja

We have measured magnetic and transport response on the polycrystalline La$_{5/8-y}$Pr$_y$Ca$_{3/8}$MnO$_3$ ($y=0.30$, average grain size 2 microns) compound. In the temperature range where ferromagnetic metallic and insulating regions coexist we observed a persistent memory of low magnetic fields ($<$ 1 T) which is determined by the actual amount of the fer

Ho Jung Hwang, Jeong Won Kang

To investigate cylindrical ultrathin copper nanowires, we performed atomistic simulations using the steepest descent method. The stable structures of the cylindrical ultrathin copper nanowires were multi-shell packs composed of coaxial cylindrical shells with {111}-like surfaces. Semiclassical orbits in a circle and circular rolling of a triangular network c

J. Casado-Pascual, J. Gómez-Ordóñez, M. Morillo, P. Hänggi

The response of a nonlinear stochastic system driven by an external sinusoidal time dependent force is studied by a variety of numerical and analytical approximations. The validity of linear response theory is put to a critical test by comparing its predictions with numerical solutions over an extended parameter regime of driving amplitudes and frequencies.

B. H. Bernhard, B. Canals, C. Lacroix

The $S=1/2$ Heisenberg antiferromagnet is studied on the kagomé lattice by using a Green&#39;s function method based on an appropriate decoupling of the equations of motion. Thermodynamic properties as well as spin-spin correlation functions are obtained and characterize this system as a two-dimensional quantum spin liquid. Spin-spin correlation functions de

B. Abdullaev, M. Musakhanov, A. Nakamura

We propose a new Complex Diffusion Monte Carlo (CDMC) method for the simulation of quantum systems with complex wave function. In CDMC the modulus and phase of wave function are simulated both in contrast to other methods. We successfully test CDMC by the simulation of the ground state for 2D electron in magnetic field and 2D fermions-anyons in parabolic wel

Parongama Sen, Somendra M. Bhattacharjee

We show that non-locality in the conservation of both the order parameter and a noncritical density (model D dynamics) leads to new fixed points for critical dynamics. Depending upon the parameters characterizing the non-locality in the two fields, we find four regions: (i) model-A like where both the conservations are irrelevant (ii) model B-like with the c

Hideo Hasegawa

Responses have been numerically studied of an ensemble of $N$ (=1, 10, and 100) Hodgkin-Huxley (HH) neurons to coherent spike-train inputs applied with independent Poisson spike-train (ST) noise and Gaussian white noise. Three interrelated issues have been investigated: (1) the difference and the similarity between the effects of the two noises, (2) the size

F. K. Chow, H. F. Chau

Minority game is a model of heterogeneous players who think inductively. In this game, each player chooses one out of two alternatives every turn and those who end up in the minority side wins. It is instructive to extend the minority game by allowing players to choose one out of many alternatives. Nevertheless, such an extension is not straight-forward due

Alister W. Graham

M32 is the prototype for the relatively rare class of galaxies referred to as `compact ellipticals&#39;. It has been suggested that M32 may be a tidally disturbed r^(1/4) elliptical galaxy, or the remnant bulge of a disk-stripped early-type spiral galaxy. This paper reveals that the surface brightness profile, the velocity dispersion measurements, and the es

Gillian Wright, Rob Ivison, Peter Hastings, Martyn Wells

Integral-field spectroscopy is the most effective method of exploiting the superb image quality of the ESO-VLT, allowing complex astrophysical processes to be probed on the angular scales currently accessible only for imaging data, but with the addition of information in the spectral dimension. We discuss science drivers and requirements for multiple deploya

Ronald A. Remillard, Michael P. Muno, Jeffrey E. McClintock, Jerome A. Orosz

We continue to investigate the X-ray timing and spectral properties of the black hole binary, XTE J1550-564. For three different groups of observations, we show evidence that two high-frequency QPOs (HFQPOs) occur simultaneously near 184 and 276 Hz. In one group, there is also evidence of a broad feature at 92 Hz. In each case, we can model the QPO profiles

Adrienne M. Juett, Herman L. Marshall, Deepto Chakrabarty, Norbert S. Schulz

We report on a 25 ks observation of the 8.7 s anomalous X-ray pulsar 4U~0142+61 with the High Energy Transmission Grating Spectrometer (HETGS) on the Chandra X-ray Observatory. The continuum spectrum is consistent with previous measurements and is well fit by an absorbed power-law + blackbody with photon index Gamma=3.3+/-0.4 and kT=0.418+/-0.013 keV. No evi

R. Manka, M. Zastawny-Kubica, A. Brzezina, I. Bednarek

The equation of state of a protoneutron star matter including the effects of magnetic field, temperature, nuclear asymmetry and trapped neutrinos are studied. Using the Oppenheimer-Volkoff-Tolman equation global parameters of the protoneutron star are obtained. Presence of the nuclear asymmetry and magnetic field make the protoneutron star more compact.

Jason Melbourne, John J. Salzer

We derive metal abundance estimates for a large sample of starbursting emission-line galaxies (ELGs). Our sample is drawn from the KPNO International Spectroscopic Survey (KISS) which has discovered over 2000 ELG candidates to date. Follow-up optical spectra have been obtained for ~900 of these objects. A three step process is used to obtain metal abundances

N. A. Webb, T. Naylor, R. D. Jeffries

Cataclysmic variables (CVs) are interacting binary systems where a cool, rapidly rotating secondary star passes material to a white dwarf. If this mass loss is to continue then there must be continuous angular momentum loss from the system. By analogy with the Sun and other cool stars, it has been assumed that magnetic braking is responsible, angular momentu

M. Coleman Miller, Douglas P. Hamilton

In the high density cores of globular clusters, multibody interactions are expected to be common, with the result that black holes in binaries are hardened by interactions. It was shown by Sigurdsson & Hernquist (1993) and others that 10 solar mass black holes interacting exclusively by three-body encounters do not merge in the clusters themselves, because r

A. C. Fabian, D. R. Ballantyne, A. Merloni, S. Vaughan

A model for the inner regions of accretion flows is presented where, due to disc instabilities, cold and dense material is clumped into deep sheets or rings. Surrounding these density enhancements is hot, tenuous gas where coronal dissipation processes occur. We expect this situation to be most relevant when the accretion rate is close to Eddington and the d

Michal Chodorowski, Pawel Ciecielag

In maximum-likelihood analyses of the Local Group (LG) acceleration, the object describing nonlinear effects is the coherence function (CF), i.e. the cross-correlation coefficient of the Fourier modes of the velocity and gravity fields. We study the CF both analytically, using perturbation theory, and numerically, using a hydrodynamic code. The dependence of

T. Di Salvo, R. Farinelli, L. Burderi, F. Frontera

We report on the results of a broad band (0.1-200 keV) spectral study of Cyg X-2 using two BeppoSAX observations taken in 1996 and 1997, respectively, for a total effective on-source time of ~100 ks. The color-color (CD) and hardness-intensity (HID) diagrams show that the source was in the horizontal branch (HB) and normal branch (NB) during the 1996 and 199

Sun Hong Rhie

Three point mass gravitational lens equation is a two-dimensional vector equation that can be embedded in a tenth order analytic polynomial equation of one complex variable, and we can solve the one variable equation on the source trajectories using recipies for Fortran or $C$ (portable for $C$++ or $C_{jj}$) in Numerical Recipes, or using packages such as M

E. Giallongo, S. Cristiani, S. D&#39;Odorico, A. Fontana

Long exposure, long-slit spectra have been obtained in the UV/optical bands for two galaxies at z=2.96 and z=3.32 to investigate the fraction of ionizing UV photons escaping from high redshifts galaxies. The two targets are among the brightest galaxies discovered by Steidel and collaborators and they have different properties in terms of Lyman-alpha emission

Daniele Spiga, Elia Battistelli, Giuliano Boella, Massimo Gervasi

Observation of the fine structures (anisotropies, polarization, spectral distortions) of the Cosmic Microwave Background (CMB) is hampered by instabilities, 1/f noise and asymmetries of the radiometers used to carry on the measurements. Addition of modulation and synchronous detection allows to increase the overall stability and the noise rejection of the ra

Yasuhiro Shioya, Kenji Bekki, Warrick J. Couch, Roberto De Propris

A one-zone chemo-spectro-photometric model is used to investigate the time evolution of disk galaxies whose star formation is truncated, and to determine the dependence of this evolution on the previous star formation history and the truncation epoch. Truncated spirals show red colors $\sim 1$ Gyr after truncation, and evolve spectrally from an e(b) type, do

Ben E. K. Sugerman, Stephen S. Lawrence, Arlin P. S. Crotts, Patrice Bouchet

We present ground-based near-infrared imaging and {\em HST} optical imaging and spectroscopy of the interaction between the ejecta of SN 1987A and its equatorial circumstellar ring. This interaction has made a transition, from emission originating in just a few ``hot spots&#39;&#39; at restricted locations in position angle around the ring, to a collision pr

M. Yu. Khlopov

Cosmoparticle physics offers the exciting challenge for the new Millenium to come to the true knowledge on the basic natural laws and on the way, they govern the creation and evolution of the Universe with all the forms of its present energy content. The theory of everything, the true history of the Universe, based on it, the new sources of energy release an

Kensuke Imanishi, Masahiro Tsujimoto, Katsuji Koyama

We present the Chandra ACIS and ASCA GIS results for a series of four long-term observations on DoAr 21, ROXs 21 and ROXs 31; the X-ray brightest T-Tauri stars (TTSs) in the Rho Ophiuchi cloud. In the four observations with a net exposure of ~600 ksec, we found six, three and two flares from DoAr 21, ROXs 21 and ROXs 31, respectively; hence the flare rate is

Lloyd Knox, Yong-Seon Song

We show that the polarization of the cosmic microwave background can be used to detect gravity waves from inflation if the energy scale of inflation is above 3.2 times 10^15 GeV. These gravity waves generate polarization patterns with a curl, whereas (to first order in perturbation theory) density perturbations do not. The limiting ``noise&#39;&#39; arises f

V. A. Sidorov, M. Nicklas, P. G. Pagliuso, J. L. Sarrao

Electrical resistivity measurements on a single crystal of the heavy-fermion superconductor CeCoIn_5 at pressures to 4.2 GPa reveal a strong crossover in transport properties near P^* \approx 1.6 GPa, where T_c is a maximum. The temperature-pressure phase diagram constructed from these data provides a natural connection to cuprate physics, including the poss

Sharmanthie Fernando

We report a new family of solutions to Einstein-Maxwell-dilaton gravity in 2+1 dimensions and Einstein-Maxwell gravity with cylindrical symmetry in 3+1 dimensions. A set of static charged solutions in 2+1 dimensions are obtained by a compactification of charged solutions in 3+1 dimensions with cylindrical symmetry. These solutions contain naked singularities

Matthias Neubert, Ben D. Pecjak

The renormalon calculus is used to calculate the terms of order $β_0^{n-1}α_s^n$ in the perturbative expansions of the Wilson coefficients and hard-scattering kernels entering the QCD factorization formula for hadronic B-meson decays into two light pseudoscalar mesons. The asymptotic behavior of the expansions is analyzed, and a minimal model of power correc

Bert Schroer

It is shown that an algebraically defined holographic projection of a QFT onto the lightfront changes the local quantum properties in a very drastic way. The expected ubiquitous vacuum polarization characteristic of QFT is confined to the lightray (longitudinal) direction, whereas operators whose localization is transversely separated are completely free of

E. H. Hwang, S. Das Sarma, V. Braude, Ady Stern

We develop a theory for frictional drag between two 2D hole layers in a dilute bilayer GaAs hole system, including effects of hole-hole and hole-phonon interactions. Our calculations suggest significant enhancement of hole drag transresistivity over the corresponding electron drag results. This enhancement originates from the exchange induced renormalization

C. D. Dermer, R. Schlickeiser

We treat transformation properties of external radiation fields in the proper frame of a plasma moving with constant speed. The specific spectral energy densities of external isotropic and accretion-disk radiation fields are derived in the comoving frame of relativistic outflows, such as those thought to be found near black-hole jet and gamma-ray burst sourc

J. Zupan

We find general solutions for the dimensionally regularised scalar one loop three-point and four-point functions with one heavy quark propagator. The scalar one-point function vanishes, while the expression for the two-point function has been found before. For the latter we give a detailed derivation. We also discuss some special cases and compile useful for

Myriam Gitti, Gianfranco Brunetti, Giancarlo Setti

We argue that the presence of diffuse synchrotron emission forming the so-called radio mini-halos in some cooling flow clusters can be explained by reacceleration of relativistic electrons, the necessary energetics being supplied by the cooling flows themselves. In particular, the reacceleration due to MHD turbulence has the correct radial dependence on the

B. Kampfer, J. Cleymans, K. Gallmeister, S. Wheaton

We analyze the centrality dependence of thermal parameters describing hadron multiplicities, hadron spectra and dilepton spectra in heavy-ion collisions at SPS and RHIC energies.

C. J. van der Beek, M. Konczykowski, A. Abaloshev, I. Abalosheva

Detailed measurements of the critical current density jc of YBa2Cu3O7 films grown by pulsed laser deposition reveal the increase of jc as function of the filmthickness. Both this thickness dependence and the field dependence of the critical current are consistently described using a generalization of the theory of strong pinning of Ovchinnikov and Ivlev [Phy

G. Busarello, Merluzzi, F. La Barbera, M. Massarotti

We present new photometric V-, R- and I-band data for the rich galaxy cluster AC 118 at z=0.31. The new photometry covers an area of 8.6x8.6 arcmin$^2$, corresponding to 2.9$\times$2.9 Mpc$^2$ (H$_0=50$ km s$^{-1}$ Mpc$^{-1}$, q$_0=0.5$ and $Λ= 0$). The data have been collected for a project aimed at studying galaxy evolution through the color-magnitude rela

M. Biesiada, J. Syska

Multidimensional theories still remain attractive from the point of view of better understanding of fundamental interactions. In this paper we consider a six - dimensional Kaluza -- Klein type model at the classical level. We derive static spherically symmetric solutions to the multidimensional Einstein equations. They are fundamentally different from four -

A. Freitas, W. Hollik, W. Walter, G. Weiglein

Recently exact results for the complete fermionic two-loop contributions to the prediction for the W-boson mass from muon decay in the electroweak Standard Model have been published [hep-ph/0007091]. This paper illustrates the techniques that have been applied for this calculation, in particular the renormalisation procedure and the treatment of IR-divergent

Michael R. Douglas, Hong Liu, Gregory Moore, Barton Zwiebach

We establish that the open string star product in the zero momentum sector can be described as a continuous tensor product of mutually commuting two dimensional Moyal star products. Let the continuous variable $κ\in [~0,\infty)$ parametrize the eigenvalues of the Neumann matrices; then the noncommutativity parameter is given by $θ(κ) =2\tanh(πκ/4)$. For each

G. Trambly de Laissardiere

The electronic structures of hexagonal beta-Al9Mn3Si and phi-Al10Mn3 are investigated through self-consistent calculations carried out using the LMTO method. This ab-initio approach is combined with an analysis of a simplified hamiltonian model for Al based alloys containing transition metal atoms. Results show a strong effect on an atomic structure stabilis

Matt Mackie

Photoassociation and the Feshbach resonance are, in principle, feasible means for creating a molecular Bose-Einstein condensate from an already-quantum-degenerate gas of atoms; however, mean-field shifts and irreversible decay place practical constraints on the efficient delivery of stable molecules using either mechanism alone. We therefore propose Feshbach

A. Amghar, B. Desplanques, L. Theussl

The effect of different boost expressions is considered for the calculation of the ground-state form factor of a two-body system made of scalar particles interacting via the exchange of a scalar boson. The aim is to provide an uncertainty range on methods employed in implementing these effects as well as an insight on their relevance when an ``exact&#39;&#39

P Bozek

The gap equation with dressed propagators is solved in symmetric nuclear matter. Nucleon self-energies are obtained within the self-consistent in medium T matrix approximation. The off-shell gap equation is compared to an effective quasiparticle gap equation with reduced interaction. At normal density, we find a reduction of the superfluid gap from 6.5MeV to

A. Montina, F. T. Arecchi

We consider a Bose-Einstein condensate (BEC) of $^7Li$ in a situation where the density undergoes a symmetry breaking in real space. This occurs for a suitable number of condensed atoms in a double well potential, obtained by adding a standing wave light field to the trap potential. Evidence of bistability results from the solution of the Gross-Pitaevskii eq

Shardha Jogee, Isaac Shlosman, Seppo Laine, Peter Englmaier

Through observations and modeling, we demonstrate how the recently discovered large-scale bar in NGC 5248 generates spiral structure which extends from 10 kpc down to 100 pc, fuels star formation on progressively smaller scales, and drives disk evolution. Deep inside the bar, two massive molecular spirals cover nearly 180 degrees in azimuth, show streaming m

M. N. Achasov, S. E. Baru, K. I. Beloborodov, A. V. Berdyugin

The $e^+e^-\toηγ\to 7γ$ process was studied in the energy range $2E=600÷1060$ MeV with an SND detector on a VEPP-2M $e^+e^-$ collider. The decay branching ratios $B(ϕ\toηγ)=(1.343\pm 0.012\pm 0.055)\cdot 10^{-2}$, $B(ω\toηγ)=(4.60\pm 0.72\pm 0.19)\cdot 10^{-4}$, and $B(ρ\toηγ)=(2.69\pm 0.32\pm 0.16)\cdot 10^{-4}$ were measured.