September 2001 arXiv papers — page 5

J. Poirier, C. D'Andrea

Project GRAND observes small variations in the number of incident muons when plotted versus local solar time. The total accumulated number of muons by GRAND over four years' time is ~140 billion. The data obtained by Project GRAND are compared with data from neutron monitor stations at Climax and at Newark which detect secondary neutrons. Project GRAND i

P. C. van der Kruit, J. Jimenez-Vicente, M. Kregel, K. C. Freeman

We present spectroscopic observations of the stellar motions in the disk of the superthin edge-on spiral galaxy IC 5249 and re-analyse synthesis observations of the HI. We find that the HI rotation curve rises initially to about 90-100 km/s, but contrary to the conclusion of Abe et al. (1999) flattens well before the edge of the optical disk. Over most part

A. Razdan, A. Haungs, H. Rebel, C. L. Bhat

In this exploratory simulation study, we compare the event-progenitor classification potential of a variety of measurable parameters of atmospheric Cherenkov pulses which are produced by ultra-high energy (UHE) gamma-ray and hadron progenitors and are likely to be recorded by the TACTIC array of atmospheric Cherenkov telescopes. The parameters derived from C

T. J. W. Lazio, J. Fischer, R. S. Foster

We report 60 and 90 micron observations of 7 millisecond pulsars with the ISOPHOT instrument and describe our analysis procedures. No pulsars were detected, and typical (3σ) upper limits are 150 mJy. We combine our results with others in the literature and use them to place constraints on the existence of protoplanetary or dust disks around millisecond pulsa

M. Ramspeck, U. Heber, S. Moehler

We present the results of quantitative spectral analyses of ten apparently normal B-type stars. These stars were found to be young massive B-type stars at distances of z=2.6 to 7.6 kpc from the galactic plane based on their positions in the (Teff, log g) diagram, normal abundance patterns and/or large projected rotational velocities. We discuss formation sce

A. Pipino, F. Matteucci, S. Borgani, A. Biviano

In this paper we show preliminary results concerning the chemical and energetic enrichment of the ICM by means of supernova-driven wind models in elliptical galaxies. These models are obtained by taking into account new prescriptions about supernova remnant evolution in the interstellar medium. We find that models, which can reproduce the Fe abundance and th

W. Kollatschny, K. Bischoff, E. L. Robinson, W. F. Welsh

We present results of a variability campaign of Mrk110 performed with the 9.2-m Hobby-Eberly Telescope (HET) at McDonald Observatory. The high S/N spectra cover most of the optical range. They were taken from 1999 November through 2000 May. The average interval between the observations was 7.3 days and the median interval was only 3.0 days. Mrk110 is a narro

T. Venturi, D. Dallacasa, A. Orfei, M. Bondi

In this paper we present the results of a 4-year (1996 - 1999) radio flux density monitoring program for a sample of X- and $γ$-ray loud blazars. Our program started in January 1996 and was carried out on monthly basis at the frequencies of 5 GHz and 8.4 GHz with the 32-m antennas located in Medicina (Bologna, Italy) and Noto (Siracusa, Italy). 22 GHz data c

Ti-pei Li

Quantities characterizing temporal property, e.g. power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and correlation between different characteristic quantities on different time scale can be studied in the time domain as well. Th

Daisuke Kawata, Brad K. Gibson

We investigate the chemo-dynamical evolution of elliptical galaxies, to understand the origin of the mass-dependence of photometric properties such as the colour-magnitude relation (CMR). Our three-dimensional TREE N-body/SPH numerical simulation takes into account both Type II and Type Ia supernovae and follows the evolution of the abundances of several che

Graham P. Smith, Ian Smail, Jean-Paul Kneib, Oliver Czoske

We present the results of a survey for Extremely Red Objects (EROs) in the fields of ten galaxy cluster lenses at z~0.2, combining high-resolution Hubble Space Telescope imaging with deep K-band imaging from UKIRT. We detect 60 EROs with R-K>=5.3, of which 26 have R-K>=6.0 in a total image plane survey area of 49arcmin^2 down to K=20.6. We use detailed model

R. W. Goodrich, R. Campbell, F. Chaffee, G. M. Hill

We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spectroscopy that shows conclusively that the C IV emission line in the z = 5.74 quasar SDSSp J104433.04-012502.2 is accompanied by broad, blueshifted C IV absorption. The line has a "balnicity index" of 900 km/s and a rest-frame equivalent width of 13.1 +/- 1

Heon-Young Chang, Suk-Jin Yoon, Chul-Sung Choi

We propose a redshift estimator for the long ($T_{90} > 20$) gamma-ray bursts (GRBs) observed by the BATSE. It is based on an empirical relation between the redshift and the power-law index of power density spectra (PDSs) of the observed GRBs. This relation is constructed by using the fact that the power-law index is dependent upon a characteristic timescale

D. Kazanas, A. Nicolaidis

We propose that the knee in the cosmic ray spectrum at energies E ~ 10^{15.5} eV is due to "new physics", namely to a channel in the high energy (~ TeV in the CM) proton interactions hitherto unaccounted for in estimating the energies of the air shower cosmic rays. The new interaction transfers part of the primary particle's energy to modes which

S. C. Ferreira Junior, M. L. Martins, M. J. Vilela

A nutrient-limited model for avascular cancer growth including cell proliferation, motility and death is presented. The model qualitatively reproduces commonly observed morphologies for primary tumors, and the simulated patterns are characterized by its gyration radius, total number of cancer cells, and number of cells on tumor periphery. These very distinct

Jonathan L. Rosner

Recent reanalyses of the atomic physics effects on the weak charge in cesium have led to a value in much closer agreement with predictions of the Standard Model. We review precision electroweak tests, their implications for upper bounds on the mass of the Higgs boson, possible ways in which these bounds may be circumvented, and the requirements placed upon a

M. A. Prieto, A. M. Perez Garcia, J. M. Rodriguez Espinosa

The relation between the X-ray, the coronal line and the infrared (IR) emissions in a sample of the brightest known Seyfert galaxies is analysed. A close relationship between the absorption-corrected soft X-ray emission and both the mid-IR and the coronal line emission is found for the Seyfert type 2 objects in the sample. The coronal line and the X-ray emis

T. B. Pittman, B. C. Jacobs, J. D. Franson

Knill, Laflamme, and Milburn recently showed that non-deterministic quantum logic operations could be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors [Nature 409, 46 (2001)]. Here we report the experimental demonstration of two logic devices of this kind, a destructive c

Michael Gronau, Jonathan L. Rosner

Recent experimental limits for the direct CP asymmetries in $B^0 \to K^+ π^-$, $B^+ \to K^+ π^0$, $B^+ \to K^0 π^+$, and $B^0 \to π^+ π^-$, and for the indirect CP asymmetry in $B^0 \to π^+ π^-$, are combined with information on CP-averaged branching ratios to shed light on weak and strong phases. At present such bounds favor $γ\ge 60^\circ$ at the $1 σ$ lev

Andrea Possenti, Rossella Cerutti, Monica Colpi, Sandro Mereghetti

The empirical relation between the X-ray luminosity (in the 2-10 keV band) and the rate of spin-down energy loss of a sample of 37 pulsars is re-examined considering recent data from ASCA, RXTE, BeppoSAX, Chandra, and XMM-Newton. The data show a significant scatter around an average correlation computed including statistical and systematic errors. All the X-

A. Andreone, A. Cassinese, C. Cantoni, E. Di Gennaro

We present a study on the power dependence of the microwave surface impedance in thin films of the novel superconductor MgB2. 500 nm thick samples exhibiting critical temperatures ranging between 26 and 38 K are synthesized by an ex-situ post-anneal of e-beam evaporated boron in the presence of an Mg vapor at 900 C. Preliminary results on films grown in situ

Kirill Krasnov

This paper studies aspects of ``holography'' for Euclidean signature pure gravity on asymptotically AdS 3-manifolds. This theory can be described as SL(2,C) CS theory. However, not all configurations of CS theory correspond to asymptotically AdS 3-manifolds. We show that configurations that do have the metric interpretation are parameterized by the s

Yu. V. Pershin, S. N. Shevchenko, I. D. Vagner, P. Wyder

Electron transport in a new low-dimensional structure - the nuclear spin polarization induced quantum wire (NSPI QW) is theoretically studied. In the proposed system the local nuclear spin polarization creates the effective hyperfine field which confines the electrons with the spins opposite to the hyperfine field to the regions of maximal nuclear spin polar

V. A. Yurovsky

Dynamics of fluctuations in unstable Bose-Einstein condensates is analyzed by the solution of approximate operator equations. In the case of a condensate with a negative scattering length the present treatment describes a delay of collapse, in agreement with recent experiments. In the case of a collision of two condensate wavepackets it is shown that quantum

M. I. Wilkinson, J. Kleyna, N. W. Evans, G. Gilmore

This paper introduces a new two-parameter family of dwarf spheroidal (dSph) galaxy models. The density distribution has a Plummer profile and falls like the inverse fourth power of distance in projection, in agreement with the star-count data. The first free parameter controls the velocity anisotropy, the second controls the dark matter content. The dark mat

Alexander Burinskii, Emilio Elizalde, Sergi R. Hildebrandt, Giulio Magli

A unified approach to regular interiors of black holes with smooth matter distributions in the core region is given. The approach is based on a class of Kerr-Schild metrics representing minimal deformations of the Kerr-Newman solution, and allows us to give a common treatment for (charged and uncharged) rotating and nonrotating black holes. It is shown that

J. T. Kleyna, M. I. Wilkinson, N. W. Evans, G. Gilmore

We present stellar radial velocity data for the Draco dwarf spheroidal galaxy obtained using the AF2/WYFFOS instrument combination on the William Herschel Telescope. Our dataset consists of 186 member stars, 159 of which have good quality velocities, extending to a magnitude V=19.5 with a mean velocity precision of 2 km/s. We find statistically strong eviden

Lydie Koch-Miramond, Martin Haas, Eric Pantin, Philipp Podsiadlowski

We have searched for evidence of emission at 15 microns with ISOCAM and at 90 microns with ISOPHOT from dust orbiting six nearby pulsars, both in binaries and in isolation, located at distances between about 100 to 1000 pc. No emission was detected at any of the pulsar positions, and for the nearest pulsar J0108-1431 the 3 sigma upper limits on the flux dens

J. Eisert, M. B. Plenio

We present a general necessary and sufficient criterion for the possibility of a state transformation from one mixed Gaussian state to another of a bi-partite continuous-variable system with two modes. The class of operations that will be considered is the set of local Gaussian completely positive trace-preserving maps.

David R. Morrison, Savdeep Sethi

We argue that there are two distinct classes of type I compactification to four dimensions on any space. These two classes are distinguished in a mysterious way by the presence (or absence) of a discrete 6-form potential. In simple examples, duality suggests that the new class of compactifications have reduced numbers of moduli. We also point out analogous d

Andrew R Liddle

This article gives a brief overview of some of the theory behind the inflationary cosmology, and discusses prospects for constraining inflation using observations. Particular care is given to the question of falsifiability of inflation or of subsets of inflationary models.

M. Rybczynski, Z. Wlodarczyk, G. Wilk

We discuss the possible imprints of Strange Quark Matter (SQM) in cosmic ray data. In particular, we investigate the propagation of SQM through the atmosphere and discuss: i) direct candidates for strangelets, ii) exotic events interpreted as signals of SQM and iii) muon bundles and delayed neutrons in Extensive Air Showers. The physics and astrophysics of S

Juan Garcia-Bellido, Ester Ruiz Morales

Recent studies suggest that the process of symmetry breaking after inflation typically occurs very fast, within a single oscillation of the symmetry-breaking field, due to the spinodal growth of its long-wave modes, otherwise known as `tachyonic preheating'. We show how this sudden transition from the false to the true vacuum can induce a significant pro

H. Herrero, A. M. Mancho

Solving numerically hydrodynamical problems of incompressible fluids raises the question of handling first order derivatives (those of pressure) in a closed container and determining its boundary conditions. We research several pressure boundary conditions for the primitive variables formulation of thermoconvective problems. In particular we study the Marang

Vladimir B. Kopeliovich

Analytical treatment of skyrmions given by rational map (RM) ansaetze proposed recently for the Skyrme model is extended to the model including the 6-th order term in chiral fields derivatives in the lagrangian (the SK6 variant of the model) and used for calculation of different properties of multiskyrmions. For special class of profile functions approximati

Pietro A. Grassi, Bernd A. Kniehl, Alberto Sirlin

Fundamental properties of unstable particles, including mass, width, and partial widths, are examined on the basis of the Nielsen identities (NI) that describe the gauge dependence of Green functions. In particular, we prove that the pole residues and associated definitions of branching ratios and partial widths are gauge independent to all orders. A simpler

A. Pimenov, A. Loidl, S. I. Krasnosvobodtsev

Far-infrared reflectance of a MgB2 film has been measured by Fourier-transform spectroscopy for frequencies 10 cm^{-1}<ν<4000 cm^{-1} above and below the superconducting transition. The data provide clear experimental evidence for the onset of a superconducting gap at 24 cm^{-1} at T=5 K. On increasing temperature the gap energy increases, contrary to what i

Richard A. Battye, N. R. Cooper, Paul M. Sutcliffe

We show that stable Skyrmions exist in two-component atomic Bose-Einstein condensates, in the regime of phase separation. Using full three-dimensional simulations we find the stable Skyrmions with topological charges Q=1 and 2, and compute their properties. With reference to these computations we suggest the salient features of an experimental setup in which

John D. Barrow, Sigbjorn Hervik

We investigate brane-worlds with a pure magnetic field and a perfect fluid. We extend earlier work to brane-worlds, and find new properties of the Bianchi type I brane-world. We find new asymptotic behaviours on approach to the singularity and classify the critical points of the dynamical phase space. It is known that the Einstein equations for the magnetic

N. Asida, A. Niégawa, H. Ozaki, M. Kubota

Using a real-time formalism of equilibrium and nonequilibrium quantum-field theory, we derive the reaction-rate formula for neutrino-conversion ($ν\to ν&#39;$) process and $ν\barν&#39;$ annihilation process, which take place in a hot and dense QED plasma with background (anti)neutrinos out of equilibrium. Also derived is the formula for the inverse processes

Roman Petryk, Kristin Schleich

We examine the Hartle-Hawking no-boundary initial state for the Ponzano-Regge formulation of gravity in three dimensions. We consider the behavior of conditional probabilities and expectation values for geometrical quantities in this initial state for a simple minisuperspace model consisting of a two-parameter set of anisotropic geometries on a 2-sphere boun

Jin Young Kim

We study the stability of the giant gravitons in the string theory background with NSNS B field. We consider the perturbation of giant gravitons formed by a probe D$(8-p)$ brane in the background generated by D$(p-2)$-D$(p)$ branes for $2 \le p \le 5$. We use the quadratic approximation to the brane action to find the equations of motion. For $p=5$, giant gr

Giovanni Amelino-Camelia, Luisa Doplicher, Soonkeon Nam, Yun-Seok Seo

We outline a phenomenological programme for the search of effects induced by (string-motivated) canonical noncommutative spacetime. The tests we propose are based, in analogy with a corresponding programme developed over the last few years for the study of Lie-algebra noncommutative spacetimes, on the role of the noncommutativity parameters in the $E(p)$ dis

A. C. de la Torre

Only the position representation is used in introductory quantum mechanics and the momentum representation is not usually presented until advanced undergraduate courses. To emphasize the relativity of the representations of the abstract formulation of quantum mechanics, two examples of representations related to the operators aX+(1-a)P and (XP+PX)/2 are pres

G. Date, Parampreet Singh

Algebraic quantization scheme has been proposed as an extension of the Dirac quantization scheme for constrained systems. Semi-classical states for constrained systems is also an independent and important issue, particularly in the context of quantum geometry. In this work we explore this issue within the framework of algebraic quantization scheme by means o

Xiaoguang Wang

We consider the superpositions of spin coherent states and study the coherence properties and spin squeezing in these states. The spin squeezing is examined using a new version of spectroscopic squeezing criteria. The results show that the antibuching effect can be enhanced and spin squeezing can be generated in the superpositions of two spin coherent states

Michal Horodecki, Pawel Horodecki, Ryszard Horodecki

We present basics of mixed-state entanglement theory. The first part of the article is devoted to mathematical characterizations of entangled states. In second part we discuss the question of using mixed-state entanglement for quantum communication. In particular, a type of entanglement that is not directly useful for quantum communcation (called bound entan

Lucien Hardy

The usual formulation of quantum theory is based on rather obscure axioms (employing complex Hilbert spaces, Hermitean operators, and the trace rule for calculating probabilities). In this paper it is shown that quantum theory can be derived from five very reasonable axioms. The first four of these are obviously consistent with both quantum theory and classi

Randall D. Peters

Although &#34;friction&#34; is included in many models of oscillator damping, including viscous ones applied to the pendulum; they &#34;miss the mark&#34; with regard to a conceptual understanding of the mechanisms responsible for energy loss. The theory of the present paper corrects some of these misunderstandings by considering the influence of internal fr

Evgenii A. Kuznetsov

Weak turbulence of magnetohydrodynamic (MHD) waves in strongly magnetized plasma is studied when the thermal pressure is less than the magnetic field pressure. In this situation the main nonlinear mechanism is the resonance scattering of fast magneto-acoustic and Alfvenic waves on slow magneto-acoustic waves. As a result, the former waves serve as the high-f

T. Ohgaki, I. Endo, M. Andreyashikin, K. Chouffani

The Relativistic Electron Facility for Education and Research (REFER) at Hiroshima University accepts a 150 MeV electron beam from a microtron, the injector to the 700 MeV storage ring of the Hiroshima Synchrotron Research Center, and keep it circulating for 2.5ms without a RF acceleration. It acts as a beam stretcher and has been used for the following rese

P. L. Chapovsky

Molecular center-of-mass motion is taken into account in the theory of coherent control of nuclear spin isomers of molecules. It is shown that infrared radiation resonant to the molecular rovibrational transition can substantially enrich nuclear spin isomers and speed up their conversion rate.

J. Dobaczewski, W. Nazarewicz, M. V. Stoitsov

Properties of density-dependent contact pairing interactions in nuclei are discussed. It is shown that the pairing interaction that is intermediate between surface and volume pairing forces gives the pairing gaps that are compatible with the experimental odd-even mass staggering. Results of the deformed Hartree-Fock-Bogoliubov calculations for this `mixed&#3

Galya Blum, Sven Gnutzmann, Uzy Smilansky

We consider the distribution of the (properly normalized) numbers of nodal domains of wave functions in 2-$d$ quantum billiards. We show that these distributions distinguish clearly between systems with integrable (separable) or chaotic underlying classical dynamics, and for each case the limiting distribution is universal (system independent). Thus, a new c

Senya Shlosman

We apply the geometric construction of solutions of some variational problems of combinatorics to estimate the number of partitions and of plane partitions of an integer.

David C. Marshall

We describe Greenberg&#39;s pseudo-null conjecture, and prove a result describing conditions under which the pseudo-null conjecture for a number field $K$ implies the conjecture for finite extensions of $K$. We then apply the result to the cyclotomic $\mathbb{Z}_p$-tower above a cyclotomic field of prime roots of unity, verifying the conjecture for a large c

Luis V. Dieulefait

We address the problem of the determination of the images of the Galois representations attached to genus 2 Siegel cusp forms of level 1 having multiplicity one. These representations are symplectic. We prove that the images are as large as possible for almost every prime, if the Siegel cusp form is not a Maass spezialform and verifies two easy to check cond

J. Donin

Let $G$ be a Lie group, $\g$ its Lie algebra, and $U_h(\g)$ the corresponding quantum group. We consider some examples of $U_h(\g)$-invariant one and two parameter quantizations on $G$-manifolds.

Frederic Laurent-Polz

We study systems formed of 2N point vortices on a sphere with N vortices of strength +1 and N vortices of strength -1. In this case, the Hamiltonian is conserved by the symmetry which exchanges the positive vortices with the negative vortices. We prove the existence of some fixed and relative equilibria, and then study their stability with the ``Energy Momen

Wolter Groenevelt, Erik Koelink

The decomposition of the tensor product of a positive and a negative discrete series representation of the Lie algebra su(1,1) is a direct integral over the principal unitary series representations. In the decomposition discrete terms can occur, and the discrete terms are a finite number of discrete series representations or one complementary series represen

Dan Avritzer, Herbert Lange

There is a canonical isomorphism between the coarse moduli spaces of somooth hyperelliptic curves of genus g and binary forms of degree 2g+2 with nonzero discriminant. In this paper, we study the extension of this isomorphism to the compactification of these moduli spaces. The main result is that the canonical isomorphism above extends to a holomorphic map f

B. Saussol, S. Troubetzkoy, S. Vaienti

We show that the Poincaré return time of a typical cylinder is at least its length. For one dimensional maps we express the Lyapunov exponent and dimension via return times.

Nikos Apostolakis

A combinatorial presentation of closed orientable 3-manifolds as bi-tricolored links is given together with two versions of a calculus via moves to manipulate bi-tricolored links without changing the represented manifold. That is, we provide a finite set of moves sufficient to relate any two manifestations of the same 3-manifold as a simple 4-sheeted branche

Lieven Le Bruyn

W. Crawley-Boevey has given a description of the set of dimension vectors of simple representations of the deformed preprojective algebras. In this note we give alternative descriptions. Note however that our descriptions depend on irreducibility of the quotient varieties, so they do NOT give a shorter proof of Crawley-Boevey&#39;s result.

Apoloniusz Tyszka

On every set A there is a rigid binary relation i.e. such a relation R \subseteq A \times A that there is no homomorphism (A,R) \rightarrow (A,R) except the identity (Vop{ě}nka et al. [1965]). We prove that for each infinite cardinal number κif card A \leq 2^κ, then there exists a relation R \subseteq A \times A with the following property: \forall (x \in A)

Joerg Schmeling, Serge Troubetzkoy

For a given rotation number we compute the Hausdorff dimension of the set of well approximable numbers. We use this result and an inhomogeneous version of Jarnik&#39;s theorem to show strong recurrence properties of the billiard flow in certain polygons

Laura Felicia Matusevich

The holonomic rank of an A-hypergeometric system $H_A(β)$ is conjectured to be independent of the parameter vector $β$ if and only if the toric ideal $I_A$ is Cohen Macaulay. We prove this conjecture in the case that $I_A$ is generic by explicitly constructing more than $\vol(A)$ many linearly independent hypergeometric functions for parameters $β$ coming fr

Michael Falk

Let $G$ be a matroid on ground set \A. The Orlik-Solomon algebra $A(G)$ is the quotient of the exterior algebra \E on \A by the ideal \I generated by circuit boundaries. The quadratic closure $\bar{A}(G)$ of $A(G)$ is the quotient of \E by the ideal generated by the degree-two component of \I. We introduce the notion of \nbb set in $G$, determined by a linea

Kirill Melnikov, Marvin Weinstein

We present a derivation of Hawking radiation based on canonical quantization of a massless scalar field in the background of a Schwarzschild black hole using Lemaitre coordinates and show that in these coordinates the Hamiltonian of the massless field is time-dependent. This result exhibits the non-static nature of the problem and shows it is better to talk

Arvind Rajaraman

We examine D-branes on $AdS_3$, and find a three-brane wrapping the entire $AdS_3$, in addition to 1-branes and instantonic 2-branes previously discussed in the literature. The three-brane is found using a construction of Maldacena, Moore, and Seiberg. We show that all these branes satisfy Cardy&#39;s condition and extract the open string spectrum on them.

Ion I. Cotaescu

The tetrad gauge invariant theory of the free Dirac field in two special moving charts of the de Sitter spacetime is investigated pointing out the operators that commute with the Dirac one. These are the generators of the symmetry transformations corresponding to isometries that give rise to conserved quantities according to the Noether theorem. With their h

Juan L. Manes

We formulate a linear difference equation which yields averaged semi-inclusive decay rates for arbitrary, not necessarily large, values of the masses. We show that the rates for decays $M \to m+\M&#39;$ of typical heavy open strings are independent of the masses $M$ and $m$, and compute the ``mass deffect&#39;&#39;$M-m-M&#39;$. For closed strings we find dec

I. Jack, D. R. T. Jones

We consider the ultra-violet divergence structure of general noncommutative supersymmetric $U(N_c)$ gauge theories, and seek theories which are all-orders finite.

C. Ringeval, P. Peter, J. -P. Uzan

We construct an explicit model to describe fermions confined on a four dimensional brane embedded in a five dimensional anti-de Sitter spacetime. We extend previous works to accommodate massive bound states on the brane and exhibit the transverse structure of the fermionic fields. We estimate analytically and calculate numerically the fermion mass spectrum o

Shun&#39;ya Mizoguchi

We examine whether any type II asymmetric orbifolds have the same massless spectrum as the dimensional reduction of D=5 simple supergravity, which, besides the eleven-dimensional supergravity, is the only known supergravity above four dimensions with no moduli. We attempt to construct such models by further twisting the orbifolds which yield D=4, N=4 pure su

Carlos Castro, Alex Granik, Jorge Mahecha

We present, using spectral analysis, a possible way to prove the Riemann&#39;s hypothesis (RH) that the only zeroes of the Riemann zeta-function are of the form s=1/2+iλ_n. A supersymmetric quantum mechanical model is proposed as an alternative way to prove the Riemann&#39;s conjecture, inspired in the Hilbert-Polya proposal; it uses an inverse eigenvalue ap

G. Weiglein

The evaluation of quantum corrections in the theory of the electroweak and strong interactions via higher-order Feynman diagrams requires complicated and laborious calculations, which however can be structured in a strictly algorithmic way. These calculations are ideally suited for the application of computer algebra systems, and computer algebra has proven

Ernest Ma, G. Rajasekaran

We explore the possibility that the 3 active (doublet) neutrinos have nearly degenerate masses which are split only by the usual seesaw mechanism from 3 sterile (singlet) neutrinos in the presence of a softly broken $A_4$ symmetry. We take the unconventional view that the sterile neutrinos may be light, i.e. less than 1 keV, and discuss some very interesting

Stefano Forte, Richard D. Ball

We discuss the theoretical underpinnings for the extraordinary success of perturbative QCD in the description of HERA data. In particular, we examine recent progress in the understanding of perturbative QCD at small x. We explain the relation between evolution equations in Q^2 and x, and how they can be used for simultaneous resummation of the relevant large

Y. Zhang, G. Fai, G. Papp, G. G. Barnafoldi

High-p_T pion and kaon production is studied in relativistic proton-proton, proton-nucleus, and nucleus-nucleus collisions in a wide energy range. Cross sections are calculated based on perturbative QCD, augmented by a phenomenological transverse momentum distribution of partons (``intrinsic k_T&#39;&#39;). An energy dependent width of the transverse momentu

A. S. Safir

We predict contributions of higher $K$-resonances to the radiative rare decays $b\to sγ$, in the framework of the QCD sum rules on the light cone, which combines the traditional QCD sum rule method with the description of final state mesons in terms of the light-cone wave functions of increasing twist. Our calculations are restricted to the leading twist-two

S. Catani, F. Krauss, R. Kuhn, B. R. Webber

We propose a method for combining QCD matrix elements and parton showers in Monte Carlo simulations of hadronic final states in $e^+e^-$ annihilation. The matrix element and parton shower domains are separated at some value $y_{ini}$ of the jet resolution, defined according to the $k_T$-clustering algorithm. The matrix elements are modified by Sudakov form f

B. Machet

I study indirect CP violation for neutral kaons, and extend it to large values of the CP-violating parameter (taken to be real). I show how and at which condition there can exist a continuous set of basis in which the kinetic and mass terms in the Lagrangian can be diagonalized simultaneously. An ambiguity results for the mass spectrum, which then depends on

C. Michael, C. McNeile, D. Hepburn, UKQCD Collaboration

We evaluate the matrix element of $\bar{q} q$ in hadron states on a lattice. We find substantial mixing of the connected and disconnected contributions so that the lattice result that the disconnected contribution to the nucleon is large does not imply that the $\bar{s} s$ content is large. This has implications for dark matter searches.

J. Skullerud, A. Kizilersu, A. G. Williams

We compute the quark-gluon vertex in quenched QCD, in the Landau gauge using an off-shell mean-field O(a)-improved fermion action. The running coupling is calculated in an `asymmetric' momentum subtraction scheme (MOM~). We obtain a crude estimate for Lambda_MSbar=170+/-65 MeV, which is considerably lower than other determinations of this quantity. However,

M. Wing

Jet cross sections in deep-inelastic scattering over a wide region of phase space have been measured at HERA. These cross section measurements provide a thorough test of the implementation of Quantum Chromodynamics in next-to-leading order (NLO) calculations. They also provide the opportunity to test the consistency of the gluon distribution in the proton as

J. Gariel, G. Marcilhacy, N. O. Santos

From a particularly simple solution of the Ernst equation, we build a solution of the vacuum stationary axisymmetric Einstein equations depending on three parameters. The parameters are associated to the total mass of the source and its angular momentum. The third parameter produces a topological deformation of the ergosphere making it a two-sheet surface, a

W. M. Stuckey

We introduce a pregeometry that provides a metric and dimensionality over a Borel set (Wheeler&#39;s &#34;bucket of dust&#34;) without assuming probability amplitudes for adjacency. Rather, a non-trivial metric is produced over a Borel set X per a uniformity base generated via the discrete topological group structures over X. We show that entourage multiplic

Mark S. Nadel

Intermediaries, like real estate agents, Consumer Reports, and Zagats, have long helped buyers to identify their most suitable options. Now, the combination of databases and the Internet enables them to serve consumers dramatically more effectively. This article begins by offering a three-part framework for understanding the evolving forms of selection assis

Kyle Nicholas

This focused study on state-level policy and access patterns contributes to a fuller understanding of how these invisible barriers work to structure access and define rural communities. Combining both quantitative and qualitative data, this study examines the role of geo-policy barriers in one of the largest and most rural states in the nation. Expanded Area

Scott C. Forbes

Commercial cellular telecommunications networks are routinely used as key means of voice and data transport by both businesses and the Public. Despite advances in encryption and other security measures, these commercial cellular networks remain extremely vulnerable to malicious attacks and the loss of user and data privacy and integrity. Such losses can resu

Markus Prior

This paper explains why, despite a marked increase in available political information on cable television and the Internet, citizens&#39; levels of political knowledge have, at best, remained stagnant (Delli Carpini & Keeter, 1996). Since the availability of entertainment content has increased too, the effect of new media on knowledge and vote likelihood sho

Johannes M. Bauer

This paper examines the effects of licensing conditions, in particular of spectrum fees, on the pricing and diffusion of mobile communications services. Seemingly exorbitant sums paid for 3G licenses in the UK, Germany in 2000 and similarly high fees paid by U.S. carriers in the re-auctioning of PCS licenses early in 2001 raised concerns as to the impacts of

Martha Fuentes-Bautista

By surveying the universal service policies in six Latin American countries, this study explores the evolution of the concept during the rollout of the telecommunication reform in the last decade. Country profiles and a set of universal service indicators provide a frame for discussing issues of accessibility and affordability of telephone service in the reg

Lee W. McKnight, Raymond Linsenmayer, William Lehr

This paper compares two models for delivering broadband wireless services: best effort vs. QoS guaranteed services. The &#39;best effort&#39; services we refer to in this paper are more commonly known as unlicensed wireless services, while the &#39;Quality of Service guaranteed&#39; services are more commonly referred to as traditional landline telephony, as

Zixiang Alex Tan

When decisions about developing standards are left to individual firms, there are many advantages including a flexible response to market evolution, accommodation to rapid technology change, and avoidance of costly coordination. However, the market process does not necessarily lead to compatible standards, especially when there is no clear market dominator.

Peter J. Love

We show that the flux-field expansion derived by Boghosian and Coveney for the Rothman-Keller immiscible fluid model can be derived in a simpler and more general way in terms of the completely symmetric tensor kernels introduced by those authors. Using this generalised flux-field expansion we show that the more complex amphiphilic model of Boghosian Coveney

Peter J. Love, Jean-Bernard Maillet, Peter V. Coveney

We report the results of a study of multiphase flow in porous media. A Darcy&#39;s law for steady multiphase flow was investigated for both binary and ternary amphiphilic flow. Linear flux-forcing relationships satisfying Onsager reciprocity were shown to be a good approximation of the simulation data. The dependence of the relative permeability coefficients

D. Voloschenko, O. P. Pishnyak, S. V. Shiyanovskii, O. D. Lavrentovich

We study photopolymerization in a low-molecular weight liquid crystal with non-uniform director gradients. Phase separation results in spatially non-uniform distribution of polymer density controlled by the distorted nematic matrix. Director-gradient-controlled polymerization provides a new and useful technique to assemble micron-scale polymer architectures.

M. Ozana, A. Shelankov

The method of two-point quasiclassical Green&#39;s function is reviewed and its applicability for description of multiple reflections/transmissions in layered structures is discussed. The Green&#39;s function of a sandwich built of superconducting layers with a semi-transparent interface is found with the help of recently suggested quasiclassical method [A.