May 2003 arXiv papers — page 5

Matthias Beck, Ricardo Diaz, Sinai Robins

We study the number of lattice points in integer dilates of the rational polytope $P = (x_1,...,x_n) \in \R_{\geq 0}^n : \sum_{k=1}^n x_k a_k \leq 1$, where $a_1,...,a_n$ are positive integers. This polytope is closely related to the linear Diophantine problem of Frobenius: given relatively prime positive integers $a_1,...,a_n$, find the largest value of t (

Nathan Seiberg

We deform the standard four dimensional $\N=1$ superspace by making the odd coordinates $θ$ not anticommuting, but satisfying a Clifford algebra. Consistency determines the other commutation relations of the coordinates. In particular, the ordinary spacetime coordinates $x$ cannot commute. We study chiral superfields and vector superfields and their interact

M. Chaichian, C. Montonen, A. Tureanu

The validity of the tree-unitarity criterion for scattering amplitudes on the noncommutative space-time is considered, as a condition that can be used to shed light on the problem of unitarity violation in noncommutative quantum field theories when time is noncommutative. The unitarity constraints on the partial wave amplitudes in the noncommutative space-ti

R. L. Thews

Predictions of J/Psi formation at RHIC via "off-diagonal" combinations of charm and anticharm quarks in a region of color deconfinement are confronted with initial data from the PHENIX collaboration. We find that the measured centrality behavior places significant constraints on the various parameters which control model calculations of J/Psi formati

F. M. L. Almeida, Y. A. Coutinho, J. A. Martins Simoes, S. Wulck

New heavy charged lepton production and decay signatures at future electron-positron colliders are investigated at $\sqrt {s}=500$ GeV. The consequences of model dependence for vector singlets and vector doublets are studied. Distributions are calculated including hadronization effects and experimental cuts that suppress the standard model background. The fi

Adrian Ghinculov

I discuss an application of numerical techniques for massive two-loop Feynman diagram evaluation to a phenomenologically very important rare decay process, B -> X_s l+l-. This process, currently being measured at B factories, has been calculated at two-loop level in the lower dilepton invariant mass perturbative window by a previous collaboration. We extende

M. Maltoni, T. Schwetz, M. A. Tortola, J. W. F. Valle

We present an analysis of the global neutrino oscillation data in terms of four-neutrino mass schemes. We find that the strong preference of oscillations into active neutrinos implied by solar+KamLAND as well as atmospheric neutrino data allows to rule out (2+2) mass schemes, whereas (3+1) schemes are strongly disfavoured by short-baseline experiments. In ad

V. Cirigliano, G. Ecker, H. Neufeld, A. Pich

We investigate the implications of large N_c and chiral symmetry for the mass spectra of meson resonances. Unlike for most other mesons, the mass matrix of the light scalars deviates strongly from its large-N_c limit. We discuss the possible assignments for the lightest scalar nonet that survives in the large-N_c limit.

Wafaa Khater, Per Osland

We study the simplest Two-Higgs-Doublet Model that allows for CP nonconservation, where it can be parametrized by only one parameter in the Higgs potential. Different concepts of maximal CP-nonconservation in the gauge-Higgs and the quark-Higgs (Yukawa) sectors are compared. Maximal CP nonconservation in the gauge-Higgs sector does normally not lead to maxim

Nicola Fabiano

We discuss the theoretical predictions for the two photon decay width of the pseudoscalar etab meson. Predictions from potential models are examined. It is found that various models are in good agreement with each other. Results for etab are also compared with those from Upsilon data through the NRQCD procedure.

V. N. Baier, V. M. Katkov

The smallness of the transverse dimensions of the colliding beams leads to suppression of bremsstrahlung cross section. This beam-size effect was discovered and investigated at INP, Novosibirsk. Different mechanisms of radiation are discussed. Separation of coherent and incoherent radiation is analyzed in detail. For linear collider this suppression affects

D. O. Caldwell, P. A. Sturrock

While KamLAND apparently rules out Resonant-Spin-Flavor-Precession (RSFP) as an explanation of the solar neutrino deficit, the solar neutrino fluxes in the Cl and Ga experiments vary with solar rotation rates. Added to this evidence, summarized here, a power spectrum analysis of the Super-Kamiokande data reveals (99.9% CL) an oscillation in the band of twice

S. I. Kruglov

The formation of scalar condensates and dynamical symmetry breaking in the U(n) four-fermion models (for n=2,3) with two coupling constants has been studied by the functional integration method. The bosonization procedures of the models under consideration are performed in one loop approximation. The propagators of fermions, collective Bose-fields (bound sta

C. Grandi

The CMS collaboration has a long term need to perform large-scale simulation efforts, in which physics events are generated and their manifestations in the CMS detector are simulated. Simulated data are then reconstructed and analyzed by the physicists to support detector design and the design of the real-time event filtering algorithms that will be used whe

C. Grandi

BOSS (Batch Object Submission System) has been developed to provide real-time monitoring and bookkeeping of jobs submitted to a compute farm system. The information is persistently stored in a relational database (MySQL in the current version) for further processing. By means of user-supplied filters, BOSS extracts the specific job information to be monitore

Marcin Nowak, Krzysztof Nienartowicz, Andrea Valassi, Magnus Lubeck

In this article we describe the migration of event data collected by the COMPASS and HARP experiments at CERN. Together these experiments have over 300TB of physics data stored in Objectivity/DB that had to be transferred to a new data management system by the end of Q1 2003 and Q2 2003 respectively. To achieve this, data needed to be processed with a rate c

U. Fricke, C. Genta, O. Gutsche, S. Hanlon

A new event visualization tool for the ZEUS experiment is nearing completion, which will provide the functionality required by the new detector components implemented during the recently achieved HERA luminosity upgrade. The new design is centered around a client-server concept, which allows to obtain random access to the ZEUS central event store as well as

K. Wrona

Electronic presentations are rapidly becoming the standard for meetings in large high energy physics collaborations. An attractive solution should combine a central repository of presentation files with easy uploading and downloading access over the wide area network. This allows all information to be instantly shared within the collaboration, including remo

S. Wheeler, J. Flammer, C. Meessen, Z. Qian

The ATLAS High Level Trigger (HLT) system provides software-based event selection after the initial LVL1 hardware trigger. It is composed of two stages, the LVL2 trigger and the Event Filter. The HLT is implemented as software tasks running on large processor farms. An essential part of the HLT is the supervision system, which is responsible for configuring,

Veronique Lefebure, Julia Andreeva

RefDB is the CMS Monte Carlo Reference Database. It is used for recording and managing all details of physics simulation, reconstruction and analysis requests, for coordinating task assignments to world-wide distributed Regional Centers, Grid-enabled or not, and trace their progress rate. RefDB is also the central database that the workflow-planner contacts

C. D. Jones

With the use of object-oriented languages for HEP, many experiments have designed their data objects to contain direct references to other objects in the event (e.g., tracks and electromagnetic showers have references to each other to denote matches). Unfortunately this creates tremendous dependencies between packages which lead to brittle development system

C. D. Jones

The traditional design of an HEP reconstruction system partitions the problem into a series of modules. A reconstruction job is then just a sequence of modules run in a particular order with each module reading data from the event and placing new data into the event. The problem with such a design is it is up to the user to place the modules in the correct o

V. Berten, L. Goossens, C. L. Tan

This paper describes the ATLAS production tool AtCom (for ATLAS Commander). The purpose of the tool is to automate as much as possible the task of a production manager: defining and submitting jobs in large quantities, following up upon their execution, scanning log files for known and unknown errors, updating the various ATLAS bookkeeping databases on succe

T. Higuchi, H. Fujii, M. Ikeno, Y. Igarashi

Data logging at an upgraded KEKB accelerator or the J-PARC facility, currently under commission, requires a high density data acquisition platform with integrated data reduction CPUs. To follow market trends, we have developed a DAQ platform based on the PCI bus, a choice which permits a fast DAQ and a long expected lifetime of the system. The platform is a

A. Undrus

NICOS, NIghtly COntrol System, is a flexible tool for coordination of software development in large-scale projects. It manages the multi-platform nightly builds based on the recent versions of software packages, tries to compensate for technical failures, tests the newly built software, identifies possible problems, and makes results immediately available to

George E. A. Matsas

We investigate and solve in the context of General Relativity the apparent paradox which appears when bodies floating in a background fluid are set in relativistic motion. Suppose some macroscopic body, say, a submarine designed to lie just in equilibrium when it rests (totally) immersed in a certain background fluid. The puzzle arises when different observe

Simon Davis

The quantum cosmological wavefunction for a quadratic gravity theory derived from the heterotic string effective action is obtained near the inflationary epoch and during the initial Planck era. Neglecting derivatives with respect to the scalar field, the wavefunction would satisfy a third-order differential equation near the inflationary epoch which has a s

Subenoy Chakraborty, N. C. Chakraborty, Ujjal Debnath

A quintessence scalar field in self-interacting Brans-Dicke theory is shown to give rise to a non-decelerated expansion of the present universe for open, flat and closed models. Along with providing a non-decelerating solution, it can potentially solve the flatness problem too.

Tanya Y. Berger-Wolf, Mitchell A. Harris

The bandwidth of a graph is the labeling of vertices with minimum maximum edge difference. For many graph families this is NP-complete. A classic result computes the bandwidth for the hypercube. We generalize this result to give sharp lower bounds for products of cliques. This problem turns out to be equivalent to one in communication over multiple channels

Alain Bazan, Thierry Bouedo, Philippe Ghez, Massimo Marino

Athena is the ATLAS off-line software framework, based upon the GAUDI architecture from LHCb. As part of ATLAS' continuing efforts to enhance and customise the architecture to meet our needs, we have developed a data object description tool suite and service for Athena. The aim is to provide a set of tools to describe, manage, integrate and use the Event

Gene Kim, MyungHo Kim

The process of diagnosing a disease from the 2D gel electrophoresis image is a challenging problem. This is due to technical difficulties of generating reproducible images with a normalized form and the effect of negative stain. In this paper, we will discuss a new concept of interpreting the 2D images and overcoming the aforementioned technical difficulties

Jean-Philippe Baud, Ben Couturier, Charles Curran, Jean-Damien Durand

In January 1999, CERN began to develop CASTOR ("CERN Advanced STORage manager"). This Hierarchical Storage Manager targetted at HEP applications has been in full production at CERN since May 2001. It now contains more than two Petabyte of data in roughly 9 million files. In 2002, 350 Terabytes of data were stored for COMPASS at 45 MB/s and a Data Cha

Roland Faller, Juan J. de Pablo

We calculate the density of states of a binary Lennard-Jones glass using a recently proposed Monte Carlo algorithm. Unlike traditional molecular simulation approaches, the algorithm samples distinct configurations according to self-consistent estimates of the density of states, thereby giving rise to uniform internal-energy histograms. The method is applied

M. S. Shell, P. G. Debenedetti, A. Z. Panagiotopoulos

We formally extend the energy landscape approach for the thermodynamics of liquids to account for saddle points. By considering the extensive nature of macroscopic potential energies, we derive the scaling behavior of saddles with system size, as well as several approximations for the properties of low-order saddles (i.e., those with only a few unstable dire

Abhishek Dhar, A. P. Young

In a disordered system one can either consider a microcanonical ensemble, where there is a precise constraint on the random variables, or a canonical ensemble where the variables are chosen according to a distribution without constraints. We address the question as to whether critical exponents in these two cases can differ through a detailed study of the ra

Serguei A. Ktitorov

The problem of determining of the relaxation time distribution in irregular relaxing systems is considered from the point of view of the Kotelnikov-Shannon theorem of the telecommunication theory.

Igor I. Smolyaninov, Jill Elliott, Anatoly V. Zayats

In this paper we report on the observation of novel and highly unusual magnetic state of light. It appears that in small holes light quanta behave as small magnets so that light propagation through such holes may be affected by magnetic field. When arrays of such holes are made, magnetic light of the individual holes forms novel and highly unusual two-dimens

Chung-Chuan Lo, Plamen Ch. Ivanov, Lus A. Nunes Amaral, Thomas Penzel

We introduce new quantitative approaches to study sleep-stage transitions with the goal of addressing the two following questions: (i) Can the new approaches provide more information on the structure of sleep-stage transitions? (ii) How does sleep fragmentation in patients with sleep apnea affect the structure of sleep-stage transitions? Our new results show

O. Pouliquen, M. Belzons, M. Nicolas

Using a refractive index matching method, we investigate the trajectories of particles in a three dimensional granular packing submitted to cyclic shear deformation. The particle motion observed during compaction is not diffusive but exhibits transient cage effect, similar to the one observed in colloidal glasses. We precisely study the statistics of the ste

Anna Delin, Erio Tosatti

We have carried out fully relativistic full-potential, spin-polarized, all-electron density-functional calculations for straight, monatomic nanowires of the 5d transition and noble metals Os, Ir, Pt and Au. We find that, of these metal nanowires, Os and Pt have mean-field magnetic moments for values of the bond length at equilibrium. In the case of Au and Ir

Baruch Meerson, Thorsten Poeschel, Yaron Bromberg

Monodisperse granular flows often develop regions with hexagonal close packing of particles. We investigate this effect in a system of inelastic hard spheres driven from below by a "thermal" plate. Molecular dynamics simulations show, in a wide range of parameters, a close-packed cluster supported by a low-density region. Surprisingly, the steady-sta

G. Balakrishnan, M. R. Lees, D. McK. Paul

Single crystal growth of several rare earth hexaborides has been carried out by the floating zone technique. A high power Xenon arc lamp image furnace was used for the crystal growth. Large high quality crystals of LaB$_{6}$, CeB$_{6}$, PrB$_{6}$ and NdB$_{6}$, about 1 cc in volume have been obtained. Crystals of all these compounds have also been grown usin

Francois G. Schmitt

Multiplicative cascades have been introduced in turbulence to generate random or deterministic fields having intermittent values and long-range power-law correlations. Generally this is done using discrete construction rules leading to discrete cascades. Here a causal log-normal stochastic process is introduced; its multifractal properties are demonstrated t

J. Roques, F. Calvo, F. Spiegelman, C. Mijoule

We investigate theoretically the progressive coating of C60 by several sodium atoms. Density functional calculations using a nonlocal functional are performed for NaC60 and Na2C60 in various configurations. These data are used to construct an empirical atomistic model in order to treat larger sizes in a statistical and dynamical context. Fluctuating charges

R. Mahendiran, Y. Breard, M. Hervieu, B. Raveau

We have investigated the magnetic properties of nanocrystalline LaCo0.5Mn0.5O3. The temperature dependence of the imaginary part of the a.c. susceptibility shows a strongly frequency dependent maximum at a temperature, Tf, which is well below the ferromagnetic transition temperature (TC ~ 230 K). The frequency dependence of Tf obeys the Arrhenius relation, f

T Sudyoadsuk, R Suryanarayanan, P Winotai, L. E. Wenger

The magnetic properties of electron-doped manganite La0.3Ca0.7MnO3 and La0.3Ca0.7Mn0.8Cr0.2O3 polycrystalline samples prepared by sol-gel technique have been investigated between 5 and 300 K in magnetic fields ranging from 0 to 5 T. The transition at 260 K, attributed to charge ordering in La0.3Ca0.7MnO3, is completely suppressed in the Cr-substituted sample

J. Bedaux, W. A. van Leeuwen

A feed-forward neural net with adaptable synaptic weights and fixed, zero or non-zero threshold potentials is studied, in the presence of a global feedback signal that can only have two values, depending on whether the output of the network in reaction to its input is right or wrong. It is found, on the basis of four biologically motivated assumptions, that

Manuel Valin-Rodriguez, Antonio Puente, Llorens Serra

Extending a previous work on spin precession in GaAs/AlGaAs quantum dots with spin-orbit coupling, we study the role of deformation in the external confinement. Small elliptical deformations are enough to alter the precessional characteristics at low magnetic fields. We obtain approximate expressions for the modified $g$ factor including weak Rashba and Dres

J. N. Fuchs, X. Leyronas, R. Combescot

We consider two regimes where a trapped Bose gas behaves as a one-dimensional system. In the first one the Bose gas is microscopically described by 3D mean field theory, but the trap is so elongated that it behaves as a 1D gas with respect to low frequency collective modes. In the second regime we assume that the 1D gas is truly 1D and that it is properly de

R. Egger, B. Trauzettel, S. Chen, F. Siano

We describe a generalization of Landauer-Büttiker theory for networks of interacting metallic carbon nanotubes. We start with symmetric starlike junctions and then extend our approach to asymmetric systems. While the symmetric case is solved in closed form, the asymmetric situation is treated by a mix of perturbative and non-perturbative methods. For N>2 rep

A. Rebei, W. N. G. Hitchon

Correlation effects of an electron gas in an external potential are derived using an Effective Action functional method. Corrections beyond the random phase approximation (RPA) are naturally incorporated by this method. The Effective Action functional is made to depend explicitly on two-point correlation functions. The calculation is carried out at imaginary

Alexander Kraskov, Harald Stoegbauer, Peter Grassberger

We present two classes of improved estimators for mutual information $M(X,Y)$, from samples of random points distributed according to some joint probability density $μ(x,y)$. In contrast to conventional estimators based on binnings, they are based on entropy estimates from $k$-nearest neighbour distances. This means that they are data efficient (with $k=1$ w

Rushan Han, Wei Guo

The notable results shown by Bozovic et al. from measurements of synthesized one-unit-cell thick of La1.85Sr0.15CuO4,La2CuO4 HTS/AF/HTS tri-layer junctions query the predictions by prevalent models since there is no observable mixing of superconductivity and anti-ferromagnetism betwween the layers. In this article we make a brief survey of experimental resul

S. M. Iftiquar

In hydrogenated amorphous silicon oxide (a-SiO:H) films, incorporation of oxygen enhances optical gap due to a large number of St-O-Si bond formation, which lies deep into valence band states. An induction effect of this Si-O on other bonds within the network also takes place. At higher oxygen content micro-void forms and bonded hydrogen accumulates in di an

Emil A. Yuzbashyan, Alexander A. Baytin, Boris L. Altshuler

The paper is devoted to the effects of superconducting pairing in small metallic grains. It turns out that at strong superconducting coupling and in the limit of large Thouless conductance one can explicitly determine the low energy spectrum of the problem. We start with the strong coupling limit and develop a systematic expansion in powers of the inverse co

Pierre Le Doussal, Kay Joerg Wiese

We study the replica field theory which describes the pinning of elastic manifolds of arbitrary internal dimension d in a random potential, with the aim of bridging the gap between mean field and renormalization theory. The full effective action is computed exactly in the limit of large embedding space dimension N. The second cumulant of the renormalized dis

M. T. Batchelor, X. -W. Guan, A. Foerster, H. -Q. Zhou

We investigate the low-temperature phase diagram of the exactly solved su(4) two-leg spin ladder as a function of the rung coupling $J_{\perp}$ and magnetic field $H$ by means of the thermodynamic Bethe Ansatz (TBA). In the absence of a magnetic field the model exhibits three quantum phases, while in the presence of a strong magnetic field there is no single

Q. A. Wang, L. Nivanen, M. Pezeril, A. Le Méhauté

In this paper, we show that 1) additive energy is not appropriate for discussing the validity of Tsallis or Rényi statistics for nonextensive systems at meta-equilibrium; 2) $N$-body systems with nonadditive energy or entropy should be described by generalized statistics whose nature is prescribed by the existence of thermodynamic stationarity. 3) the equiva

A. Shnirman, D. Mozyrsky, I. Martin

We calculate the noise spectrum of the output signal of a quantum detector during continuous measurement of a two-level system (qubit). We generalize the previous results obtained for the regime of high voltages (when $eV$ is much larger than the qubit's energy level splitting $Δ$) to the case of arbitrary voltages and temperatures. When $V \sim Δ$ the o

A. L. Cornelius, B. Light, J. J. Neumeier

Measurements of the specific heat on the system Ca$_{1-x}$La$_{x}$MnO$_{3}$ (% $x\leq 0.10$) are reported. Particular attention is paid to the effect that doping the parent compound with electrons by substitution of La for Ca has on the magnetic ground state. The high ($T>40$ K) temperature data reveals that doping decreases $T_{N}$ from 122 K for the undope

H. Kjeldsen, T. R. Bedding, I. K. Baldry, H. Bruntt

We obtained time-series spectroscopy of the G0 subgiant eta Boo in an attempt to confirm the solar-like oscillations reported by Kjeldsen et al. (1995). We recorded 1843 spectra over six consecutive nights with the Nordic Optical Telescope, which we used to measure equivalent widths of strong temperature-sensitive lines. We also measured velocities from 1989

Gia Dvali, Andrei Gruzinov, Matias Zaldarriaga

We generalize a recently proposed mechanism for the origin of primordial metric perturbations in inflationary models. Quantum fluctuations of light scalar fields during inflation give rise to super-horizon fluctuations of masses and reaction rates of various particles. Reheating, freeze-out, and matter-domination processes become inhomogeneous and generate s

Marcin Sawicki, Gabriela Mallen-Ornelas

We present a catalog of 97 spectroscopic redshifts of z<1 galaxies in the Hubble Deep Field South (HDFS) and its Flanking Fields (FFs). In the HDFS proper, we observed approximately half the galaxies brighter than I(AB)=24 and obtained redshifts for 76% of them. Targets in our HDFS sample were pre-selected to be at z<1 based on photometric redshifts, while i

K. W. Smith, M. Pestalozzi, M. Guedel, J. Conway

We report observations of the T Tauri system at 8.4 GHz with a VLBI array comprising the VLBA, VLA and Effelsberg 100m telescopes. We detected a compact source offset approximately 40 mas from the best infrared position of the T Tau Sb component. This source was unresolved, and constrained to be less than 0.5 mas in size, corresponding to 0.07 AU or 15 R$_{\

R. P. Mignani, A. De Luca, O. Kargaltsev, G. G. Pavlov

Observations of the Vela pulsar region with the Chandra X-ray observatory have revealed the fine structure of its synchrotron pulsar-wind nebula (PWN), which showed an overall similarity with the Crab PWN. However, contrary to the Crab, no firm detection of the Vela PWN in optical has been reported yet. To search for the optical counterpart of the X-ray PWN,

J. Daszynska-Daszkiewicz, W. A. Dziembowski, A. A. Pamyatnykh

In Delta Scuti star models, the calculated amplitude ratios and phase differences for multi-colour photometry exhibit a strong dependence on convection. These observables are tools for determination of the spherical harmonic degree of the excited modes. The dependence on convection enters through the complex parameter f, which describes bolometric flux pertu

Maciej Konacki, Alex Wolszczan

We present measurements of the true masses and orbital inclinations of the two Earth-mass planets in the PSR B1257+12 system, based on the analysis of their mutual gravitational perturbations detectable as microsecond variations of the arrival times of radio pulses from the pulsar. The 6.2-millisecond pulsar, PSR B1257+12, has been regularly timed with the A

F. -J. Zickgraf, D. Engels, H. -J. Hagen, D. Reimers

We present the Hamburg/RASS Catalogue (HRC) of optical identifications of X-ray sources at high-galactic latitude. The HRC includes all X-ray sources from the ROSAT Bright Source Catalogue (RASS-BSC) with galactic latitude |b| >= 30 degr and declination delta >= 0 degr. In this part of the sky covering ~10 000 deg^2 the RASS-BSC contains 5341 X-ray sources.

C. Eleftheriadis et al

The CERN Axion Solar Telescope (CAST) searches for axions coming from photon to axion conversion in the sun&#39;s core, as stated by the Primakoff effect. Axions arise in particle physics as a consequence of the breaking of Peccei-Quinn symmetry which has been introduced as a solution to the strong CP problem. As cosmological axions they are candidates for a

M. Kozlowski, J. Marciak-Kozlowska

Following the coincidence A x atomic year ~ Earth year (s), (A = Avogardo number, atomic year=a_B/alpha c, a_B=Bohr radius, alpha= fine structure constant, c=light velocity) and considering the &#34;niche&#34; for alpha, i.e. 180^{-1}<alpha<85^{-1}, the Ecosphere radius is calculated. Key words: Fine structure constant; Planet orbit radii.

M. Kraus

A radiation transfer model for the top-layer of a flared dust disk around a low mass star is presented. The disk structure, temperature distribution and spectral energy distribution are compared with the results of the analytical two-layer model of Chiang & Goldreich. We find that both, a proper iterative calculation of the main parameters and proper radiati

M. R. Schreiber, B. T. Gaensicke

We present a sample of 30 well observed Post Common Envelope Binaries (PCEBs). Deriving the cooling age of the white dwarfs, we show that the PCEB population is dominated by young systems. Having calculated the orbital evolution of the systems under the assumption of two different prescriptions for the angular momentum loss, we find that most of the systems

P. Rautiainen, H. Salo, R. Buta

ESO 566-24 is an extraordinary barred galaxy, which has four regularly spaced spiral arms in blue light images. This type of four-armed spiral structure, which is rare among the spiral population, is clearly seen also in near-infrared images, and thus is present in the old stellar population. We have constructed dynamical models of ESO 566-24 in order to und

T. Sanuki, M. Fujikawa, K. Abe, K. Anraku

Measurement of cosmic-ray proton, antiproton and muon spectra was carried out at mountain altitude. We observed 2 x 10^5 protons and 10^2 antiprotons in a kinetic energy region of 0.25 -- 3.3 GeV. Zenith-angle dependence of proton fluxes was obtained. Atmospheric muon spectra were measured simultaneously. The observed antiproton spectrum showed some deviatio

James E. Lidsey

An introductory review of the Randall-Sundrum type II braneworld scenario is presented, with emphasis on the relationship between the density and gravitational wave perturbations that are generated during inflation. The implications of relaxing the reflection symmetry in the fifth dimension are considered. The effects of including a Gauss-Bonnet combination

Nir J. Shaviv, Avishai Dekel

We revisit the evaporation process of gas from dwarf galaxies after it has been photo-ionized by the UV flux from the first stars and AGNs and heated to T~10^4K or 2x10^4K respectively. Earlier estimates, based on the balance between pressure and gravity, indicated that dark haloes of virial velocity lower than Vevap ~ 11-13 km/s have lost most of their gas

T. D. Saini, J. Weller, S. L. Bridle

We apply the Bayesian concept of `evidence&#39; to reveal systematically the nature of dark energy from present and future supernova luminosity distance measurements. We express the unknown dark energy equation of state w(z) as a low order polynomial in redshift and use evidence to find the polynomial order, thereby establishing the minimum order required by

T. R. Saitoh, J. Koda

We describe a new method to accelerate neighbor searches on GRAPE, i.e. a special purpose hardware that efficiently calculates gravitational forces and potentials in $N$-body simulations. In addition to the gravitational calculations, GRAPE simultaneously constructs the lists of neighbor particles that are necessary for Smoothed Particle Hydrodynamics (SPH).

E. Pancino, A. Seleznev, F. R. Ferraro, M. Bellazzini

We present a detailed analysis of the spatial distribution of the stellar populations in the Galactic globular cluster omega Centauri. Taking advantage of the large photometric catalog published by Pancino et al. (2000), we confirm that metal-rich populations have a spatial distribution which is significantly different from the metal-poor dominant population

M. J. Kuchner, D. N. Spergel

Directly imaging extrasolar planets using a monolithic optical telescope avoids many pitfalls of space interferometry and opens up the prospect of visible light studies of extrasolar planetary systems. Future astronomical missions may require interferometry for high spatial resolution, but given that the first direct imaging missions will probably fit into a

J. Zavala, V. Avila-Reese, H. Hernandez-Toledo, C. Firmani

For a compiled sample of disk galaxies with available photometry (B and K bands), velocity line-widths and HI integral fluxes, several parameters which trace the luminous, baryonic and dark matter contents were inferred. We investigated how these parameters do vary with different galaxy properties, and confronted the results with predictions of galaxy evolut

Naoki Yoshida, Aaron Sokasian, Lars Hernquist, Volker Springel

(abridged) We study high redshift structure formation and reionization in a LCDM universe under the assumption that the spectral power index of primordial density fluctuations is a function of length scale. We adopt a particular formulation of the running spectral index (RSI) model as suggested by the recent WMAP data. While early structure forms hierarchica

H. Lu, C. N. Pope, E. Sezgin

N=(1,0) supergravity in six dimensions admits AdS_3\times S^3 as a vacuum solution. We extend our recent results presented in hep-th/0212323, by obtaining the complete N=4 Yang-Mills-Chern-Simons supergravity in D=3, up to quartic fermion terms, by S^3 group manifold reduction of the six dimensional theory. The SU(2) gauge fields have Yang-Mills kinetic term

Merab Gogberashvili, Douglas Singleton

A new solution to Einstein equations in (1+5)-spacetime with an embedded (1+3) brane is given. This solution localizes the zero modes of all kinds of matter fields and 4-gravity on the (1+3) brane by an increasing, transverse gravitational potential. This localization occurs despite the fact that the gravitational potential is not a decreasing exponential, a

Witold Skiba, John Terning

We construct a little Higgs model using a simple global symmetry group SU(9) spontaneously broken to SU(8). The electroweak interactions are extended to SU(3)xU(1) and embedded in SU(9). At the electroweak scale, our model is a two Higgs-doublet model. At the TeV scale, there are additional states, which are responsible for the cancellation of one loop quadr

John T. Giblin, Donald Marolf, Robert H. Garvey

We show that it is possible to embed the 1+1 dimensional reduction of certain spherically symmetric black hole spacetimes into 2+1 Minkowski space. The spacetimes of interest (Schwarzschild de-Sitter, Schwarzschild anti de-Sitter, and Reissner-Nordstrom near the outer horizon) represent a class of metrics whose geometries allow for such embeddings. The embed

M. de Llano, A. Salazar, M. A. Solis

It is well-known that a delta potential well in 1D has only one bound state but that in 3D it supports an {\it infinite} number of bound states with {\it infinite} binding energy for the lowest level. We show how this also holds for the less familiar 2D case, and then discuss why this makes 3D delta potential wells unphysical as models of interparticle inter

Cristian Predescu, Dubravko Sabo, J. D. Doll, David L. Freeman

We perform a thorough analysis on the choice of estimators for random series path integral methods. In particular, we show that both the thermodynamic (T-method) and the direct (H-method) energy estimators have finite variances and are straightforward to implement. It is demonstrated that the agreement between the T-method and the H-method estimators provide

Jianxiang Wang, David Merritt

We compute rates of tidal disruption of stars by supermassive black holes in galactic nuclei, using downwardly-revised black hole masses from the M-sigma relation. In galaxies with steep nuclear density profiles, which dominate the overall event rate, the disruption frequency varies inversely with assumed black hole mass. We compute a total rate for non-dwar

Joshua Feinberg

We review in detail the construction of {\em all} stable static fermion bags in the 1+1 dimensional Gross-Neveu model with $N$ flavors of Dirac fermions, in the large $N$ limit. In addition to the well known kink and topologically trivial solitons (which correspond, respectively, to the spinor and antisymmetric tensor representations of O(2N)), there are als

S. S. Adler

First results on charm quarkonia production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/Psi's measured in the PHENIX experiment via electron-positron decay pairs at mid-rapidity for Au-Au reactions at sqrt(s_NN) = 200 GeV are analyzed as a function of collision centrality. For this analysis we have stud

Mark Dijkstra, Adam Lidz, Lam Hui

Absorption between the rest-frame wavelengths of 973 and 1026 Angstroms in quasar spectra arises from two sources (apart from occasional metals): one is due to Lyman-alpha (Lya) absorption by materials at a low redshift, and the other from Lyman-beta (Lyb) at a higher redshift. These two sources of absorption are to a good approximation uncorrelated because

Jihn E. Kim, Bumseok Kyae, Qaisar Shafi

We show that a self-tuning mechanism of the cosmological constant could work in 5D non-compact space-time with a $Z_2$ symmetry in the presence of a massless scalar field. The standard model matter fields live only on the 4D brane. The change of vacuum energy on the brane (brane cosmological constant) by, for instance, electroweak and QCD phase transitions,

G. Alvarez, E. Dagotto

We argue that several materials of much current interest in condensed matter physics share common phenomenological aspects that only very recent investigations are unveiling. The list includes colossal magnetoresistance manganites, high temperature superconducting cuprates, diluted magnetic semiconductors, and others. The common aspect is the relevance of in

Z. Burda, A. Goerlich, A. Jarosz, J. Jurkiewicz

Using random matrix technique we determine an exact relation between the eigenvalue spectrum of the covariance matrix and of its estimator. This relation can be used in practice to compute eigenvalue invariants of the covariance (correlation) matrix. Results can be applied in various problems where one experimentally estimates correlations in a system with m

C. Armendariz-Picon, Vikram Duvvuri

In the context of (4+d)-dimensional general relativity, we propose an inflationary scenario wherein 3 spatial dimensions grow large, while d extra dimensions remain small. Our model requires that a self-interacting d-form acquire a vacuum expectation value along the extra dimensions. This causes 3 spatial dimensions to inflate, whilst keeping the size of the

Peter L. Knight, Eugenio Roldan, J. E. Sipe

We discuss how the coined quantum walk on the line or on the circle can be implemented using optical waves. We propose several optical cavity configurations for these implementations.

George F. R. Ellis, Jean-Philippe Uzan

Theories proposing a varying speed of light have recently been widely promoted under the claim that they offer an alternative way of solving the standard cosmological problems. Recent observational hints that the fine structure constant may have varied during over cosmological scales also has given impetus to these models. In theoretical physics the speed of

Rodolfo Gambini, Rafael Porto, Jorge Pullin

We show that a recent proposal for the quantization of gravity based on discrete space-time implies a modification of standard quantum mechanics that naturally leads to a loss of coherence in quantum states of the type discussed by Milburn. The proposal overcomes the energy conservation problem of previously proposed decoherence mechanisms stemming from quan

A. De Martino, I. Giardina, G. Mosetti

We study the asymptotic macroscopic properties of the mixed majority-minority game, modeling a population in which two types of heterogeneous adaptive agents, namely ``fundamentalists&#39;&#39; driven by differentiation and ``trend-followers&#39;&#39; driven by imitation, interact. The presence of a fraction f of trend-followers is shown to induce (a) a sign