August 1998 arXiv papers — page 7

Jongsoo Kim, S. S. Hong, Dongsu Ryu, T. W. Jones

Using an isothermal MHD code, we have performed three-dimensional, high-resolution simulations of the Parker instability. The initial equilibrium system is composed of exponentially-decreasing isothermal gas and magnetic field (along the azimuthal direction) under a uniform gravity. The evolution of the instability can be divided into three phases: linear, n

N. Graham, R. L. Jaffe

We consider one-loop quantum corrections to soliton energies and central charges in the supersymmetric $ϕ^4$ and sine-Gordon models in 1+1 dimensions. In both models, we unambiguously calculate the correction to the energy in a simple renormalization scheme and obtain $ΔH = - m/(2π)$, in agreement with previous results. Furthermore, we show that there is an

L. E. Ibanez, R. Rabadan, A. M. Uranga

We study the cancellation of U(1) anomalies in Type I and Type IIB D=4, N=1 string vacua. We first consider the case of compact toroidal $Z_N$ Type IIB orientifolds and then proceed to the non-compact case of Type IIB D3 branes at orbifold and orientifold singularities. Unlike the case of the heterotic string we find that for each given vacuum one has generi

Jean M. Quashnock, Michael L. Stein

We examine the line-of-sight clustering of QSO heavy-element absorption-line systems, using a new measure of clustering, called the reduced second moment measure, that directly measures the mean over-density of absorbers. While closely related to other second-order measures such as the correlation function or the power spectrum, this measure has a number of

David Eliezer, Ian I. Kogan

We propose a series of simple models for the microstructure of a double auction market without intermediaries. We specialize to those markets, such interdealer broker markets, which are dominated by professional traders, who trade mainly through limit orders, watch markets closely, and move their limit order prices frequently. We model these markets as a set

Carleton DeTar, Olaf Kaczmarek, Frithjof Karsch, Edwin Laermann

The separation of a heavy quark and antiquark pair leads to the formation of a tube of flux, or string, which should break in the presence of light quark-antiquark pairs. This expected zero temperature phenomenon has proven elusive in simulations of lattice QCD. We present simulation results that show that the string does break in the confining phase at nonz

P. Sebbah, O. Legrand, A. Z. Genack

The temporal evolution of microwave pulses transmitted through random dielectric samples is obtained from the Fourier transform of field spectra. Large fluctuations are found in the local or single channel delay time, which is the first temporal moment of the transmitted pulse at a point in the output speckle pattern. Both positive and negative values of loc

D. O. Riska

The strange magnetic moment of the proton is small in the chiral quark model, because of a near cancellation between the quantum fluctuations that involve kaons and $s$-quarks and loops that involve radiative transitions between strange vector mesons and kaons.

Tomomi Nio, Takuya Matsuda, Jun Fukue

Hoyle-Lyttleton type accretion is investigated, by taking account of not only the effect of radiation pressure but the effect of radiation drag. We calculate the trajectories of particles for three cases: only the effect of gravity is considered (case A); the effect of radiation pressure is taken into account (case B); the effect of radiation drag as well as

Paolo Zanardi, Fausto Rossi

A potential implementation of quantum-information schemes in semiconductor nanostructures is studied. To this end, the formal theory of quantum encoding for avoiding errors is recalled and the existence of noiseless states for model systems is discussed. Based on this theoretical framework, we analyze the possibility of designing noiseless quantum codes in r

Yoshio Kikukawa, Atsushi Yamada

We discuss the exact chiral symmetry and its spontaneous breakdown in lattice QCD with the Dirac operators satisfying the Ginsparg-Wilson relation. The axial vector current, which turns out to be related to the vector current simply by the insertion of the operator γ_5 (1-aD), is explicitly constructed in the case of the Neuberger-Dirac operator. We also con

L. E. Cram

The decimetric luminosity of many galaxies appears to be dominated by synchrotron emission excited by supernova explosions. Simple models suggest that the luminosity is directly proportional to the rate of supernova explosions of massive stars averaged over the past 30 Myr. The proportionality may be used together with models of the evolving 1.4 GHz luminosi

G. Ghosh, V. S. Sastry, C. S. Sundar, Surajit Sengupta

We follow the structural transformation in solid C$_{70}$ from the high temperature hcp to a low temperature monoclinic phase using x-ray diffraction studies at controlled cooling-rates from 0.0033 to 0.42 K/min. Rapid cooling of the sample gives the signature of a two-step transformation which disappears when the system is transformaed quasi-statically. The

G. Kälbermann

A model of a fluid of skyrmions coupled to a scalar and to the $ø$ meson mean fields is developed. The central and spin-orbit potentials of a skyrmion generated by the fields predict correct energy levels in selected closed shell nuclei. The effect of the meson fields on the properties of skyrmions in nuclei is investigated.

L. Vaidman, N. Yoran

Recent experimental results and proposals towards implementation of quantum teleportation are discussed. It is proved that reliable (theoretically, 100% probability of success) teleportation cannot be achieved using the methods applied in recent experiments, i.e., without quantum systems interacting one with the other. Teleportation proposal involving atoms

N Linden H Barjat R Freeman

A new approach to the implementation of a quantum computer by high-resolution nuclear magnetic resonance (NMR) is described. The key feature is that two or more line-selective radio-frequency pulses are applied simultaneously. A three-qubit quantum computer has been investigated using the 400 MHz NMR spectrum of the three coupled protons in 2,3-dibromopropan

Shi-Hai Dong, Xi-Wen Hou, Zhong-Qi Ma

The two-dimensional Levinson theorem for the Klein-Gordon equation with a cylindrically symmetric potential $V(r)$ is established. It is shown that $N_{m}π=π(n_{m}^{+}-n_{m}^{-})= [δ_{m}(M)+β_{1}]-[δ_{m}(-M)+β_{2}]$, where $N_{m}$ denotes the difference between the number of bound states of the particle $n_{m}^{+}$ and the ones of antiparticle $n_{m}^{-}$ wi

Shi-Hai Dong, Xi-wen Hou, Zhong-Qi Ma

By making use of an ${\it ansatz}$ for the eigenfunction, we obtain the exact solutions to the Schrödinger equation with the anharmonic potential, $V(r)=a r^2+b r^{-4}+c r^{-6}$, both in three dimensions and in two dimensions, where the parameters $a$, $b$, and $c$ in the potential satisfy some constraints.

Paul B. Slater

We extend to additional probability measures and scenarios, certain of the recent results of Krattenthaler and Slater (quant-ph/9612043), whose original motivation was to obtain quantum analogs of seminal work on universal data compression of Clarke and Barron. KS obtained explicit formulas for the eigenvalues and eigenvectors of the 2^m x 2^m density matric

Luigi Foschini

The unexpected discoveries at the beginning of the century, particularly thanks to Heisenberg, Bohr, and Godel, has driven the science to drastic changes, opening new, extraordinary, and infinite research fields. After this, many scientists saw, and still today see, a crisis, with dreadful meaning, in the science. However, this crisis is only present in that

Jongbae Hong, Heekyong Kim

We find power-law behaviors of grain velocity in both propagation and backscattering in a gravitationally compacted granular chain with nonlinear contact force. We focus on the leading peak of the velocity signal which decreases in a power-law $d^{-α}$, where $d$ is the location of the peak, as the signal goes down. The ratio of backscattered to incident lea

C. Beck

The results presented in this paper clearly suggest that a coherent framework may exist which connects the topics of heavy-ion molecular resonances, hyperdeformation effects, and fission shape isomerism. New data on particle-particle-$γ$ triple coincidences of the $^{28}$Si+$^{28}$Si reaction at a beam energy corresponding to the population of a conjectured

H. J. S. Dorren

We present a novel method to estimate the stability of the Marchenko equation for finite data-sets. We show that we can derive a recursion relationship for the Fourier expansion coefficients of the kernel which is solved by the Marchenko equation. The method can easily be implemented numerically. Moreover, we discus the stability of the one-dimensional inver

Richard Dipper, Jochen Gruber

We introduce a generalized version of a q-Schur algebra (of parabolic type) for arbitrary Hecke algebras over extended Weyl groups. We describe how the decomposition matrix of a finite group with split BN-pair, with respect to a non-describing prime, can be partially described by the decomposition matrices of suitably chosen q-Schur algebras. We show that th

Joel David Hamkins

The automorphism tower of a group is obtained by computing its automorphism group, the automorphism group of THAT group and so on, iterating transfinitely. Each group maps into the next using inner automorphisms and one takes a direct limit at limit stages. The question is whether the process ever terminates in a fixed point, a group which is isomorphic to i

Joel David Hamkins, Andy Lewis

We extend in a natural way the operation of Turing machines to infinite ordinal time, and investigate the resulting supertask theory of computability and decidability on the reals. The resulting computability theory leads to a notion of computation on the reals and concepts of decidability and semi-decidability for sets of reals as well as individual reals.

Philip C. Argyres, Savas Dimopoulos, John March-Russell

Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at a TeV and the observed weakness of gravity at long distances is due the existence of new sub-millimeter spatial dimensions. In this letter, we study how the properties of black holes are al

Chang Soo Park, Myung Geun Jeong, Sahng-Kyoon Yoo, D. K. Park

We derive a general WKB energy splitting formula in a double-well potential by incorporating both phase loss and anharmonicity effect in the usual WKB approximation. A bare application of the phase loss approach to the usual WKB method gives better results only for large separation between two potential minima. In the range of substantial tunneling, however,

Marco Cavaglia

I briefly summarize recent results on classical and quantum dilaton gravity in 1+1 dimensions.

Marco Cavaglia

We briefly present two-dimensional dilaton gravity from the point of view of integrable systems.

A. Gorsky

We discuss the brane interpretation of the integrable dynamics behind the exact solution to the N=2 SUSY YM theory. Degrees of freedom in the first integrable system responsible for the spectral Riemann surfaces comes from the hidden Higgs branch of the moduli space. The second integrable system of the Whitham type yields the dynamics on the Coulomb branch a

Joachim Lindig

Adiabatic vacua are known to be Hadamard states. We show, however that the energy-momentum tensor of a linear Klein-Gordon field on Robertson-Walker spaces developes a generic singularity on the initial hypersurface if the adiabatic vacuum is of order less than four. Therefore, adiabatic vacua are physically reasonable only if their order is at least four. A

Gianluca Oderda

We discuss rapidity-gap events between two jets produced at high momentum transfer in $p$ $\bar{p}$ scattering, from the point of view of the soft energy flow into the interjet region. We define a gap cross section and, in perturbative QCD (pQCD), resum all the leading logarithms in the soft intermediate energy. We show that the numerical result from our cro

T. S. Evans

I compute the derivative expansion of an effective action at finite temperature using the imaginary time approach. I show that it is a well behaved expansion giving a unique seriers contrary to previous results. This disparity is shown to originate in the choice of thermal Green functions used in the calculations.

J. F. Bennett, J. A. Gracey

We describe the evaluation of the anomalous dimensions of twist-2 deep inelastic light cone operators to O(1/N_f) as a check on future perturbative calculations. In particular we present recent results for the singlet gluonic operator dimension in polarised and unpolarised scattering and give three loop predictions for the O(1/N_f) gluonic eigenoperator. The

J. Ambjorn, K. N. Anagnostopoulos, T. Ichihara, L. Jensen

We study the diffusion equation in two-dimensional quantum gravity, and show that the spectral dimension is two despite the fact that the intrinsic Hausdorff dimension of the ensemble of two-dimensional geometries is very different from two. We determine the scaling properties of the quantum gravity averaged diffusion kernel.

T. Reisz

Two flavour massless QCD has a second order chiral transition which has been argued to belong to the universality class of the $3d$ O(4) spin model. The arguments have been questioned recently, and the transition was claimed to be mean field behaved. We discuss this issue at the example of the $3d$ Gross-Neveu model. A solution is obtained by applying variou

V. V. Frolov et al

We studied the electroproduction of the Delta(1232) resonance via the reaction p(e,e'p)\pi0 at four-momentum transfers Qsq = 2.8 and 4.0 GeV^2. This is the highest Qsq for which exclusive resonance electroproduction has ever been observed. Decay angular distributions for Delta to p-pi0$ were measured over a wide range of barycentric energies covering the

The OPAL Collaboration, G. Abbiendi et al

Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward asymmetries for the leptonic final states have also been measured. Cross-sections and asymmetries are also presented for data

A. T. Doyle

The latest results from the ZEUS experiment, as presented at the DIS98 workshop, are reviewed. A brief introduction to the status of the experiment is given. The review focuses on three areas: multi-scale problems in QCD including results on jets, charm, the dynamics of $F_2$ at low $Q^2$, forward jets and fragmentation functions; diffractive structure inclu

Makoto Narita

We show the rigid singularity theorem, that is, a globally hyperbolic spacetime satisfying the strong energy condition and containing past trapped sets, either is timelike geodesically incomplete or splits isometrically as space $\times$ time. This result is related to Yau's Lorentzian splitting conjecture.

M. Chaves

It is odd that chess grandmasters often disagree in their analysis of positions, sometimes even of simple ones, and that a grandmaster can hold his own against an powerful analytic machine such as Deep Blue. The fact that there must exist pure winning strategies for chess is used to construct a control strategy function. It is then shown that chess strategy

S. C. Benjamin, N. F. Johnson

We present a new cellular data processing scheme, a hybrid of existing cellular automata (CA) and gate array architectures, which is optimized for realization at the quantum scale. For conventional computing, the CA-like external clocking avoids the time-scale problems associated with ground-state relaxation schemes. For quantum computing, the architecture c

G. D. Lythe

Spatiotemporal evolution in the real Ginzburg-Landau equation is studied with space-time noise and a slowly increasing critical parameter. Analytical estimates for the characteristic size of the domains formed in a slow sweep through the critical point agree with the results of finite difference solution of the stochastic PDEs.

Igor Tsatskis

A method for calculating the short-range order part of the free energy of order-disorder systems is proposed. The method is based on the apllication of the cumulant expansion to the exact configurational entropy. Second-order correlation corrections to the mean-field approximation for the free energy are calculated for arbitrary thermodynamic phase and type

E. Harikumar, C. Nagaraja Kumar, M. Sivakumar

Recently non-topological chiral soliton solutions were obtained in a derivatively coupled non-linear Schrödinger model in 1+1 dimensions. We extend the analysis to include a more general self-coupling potential (which includes the previous cases) and find chiral soliton solutions. Interestingly even the magnitude of the velocity is found to be fixed. Energy

Joachim Hermisson

We study thermodynamic properties, specific heat and susceptibility, of XY quantum chains with coupling constants following arbitrary substitution rules. Generalizing an exact renormalization group transformation, originally formulated for Ising quantum chains, we obtain exact relevance criteria of Harris-Luck type for this class of models. For two-letter su

D. M. Schaller, D. E. Buergler, C. M. Schmidt, F. Meisinger

By means of magneto-optical Kerr effect we observe spin reorientations from in-plane to out-of-plane and vice versa upon annealing thin Fe films on Ag(001) at increasing temperatures. Scanning tunneling microscopy images of the different Fe films are used to quantify the surface roughness. The observed spin reorientations can be explained with the experiment

V. Cherepanov, I. Ya. Korenblit, Amnon Aharony, O. Entin-Wohlman

The effect of quenched random ferromagnetic bonds on the antiferromagnetic correlation length of a two--dimensional Heisneberg model is studied, applying the renormalization group method to the classical non--linear sigma model with quenched random dipole moments. It is found that the antiferromagnetic long range order is destroyed for any non--zero concentr

Jung Hoon Han, S. -R. Eric Yang

We present a set of explicit trial wavefunctions for the filling factors ν=n/(2n\pm 1) and ν=1/2 in the symmetric gauge. We show that the zeroes of the wavefunction, except those dictated by the Fermi statistics, are detached from the particles. The evolution of zeroes as the filling factor is varied is examined. We show that the wavefunction at half-filling

Sang-Hoon Kim, Hyun Sik Noh, Dae Kwan Kim, Chul Koo Kim

A dilute Bose gas system is studied using the functional Schrödinger picture theory. The ground state properties are obtained by solving the infinite dimensional Schrödinger equation variationally. It is shown that a shifted Gaussian trial wavefunctional enables us to calculate a higher order correction, which corresponds to the fluctuation contribution from

V. Pagel, K. Lenzo, A. Black

This paper presents trainable methods for generating letter to sound rules from a given lexicon for use in pronouncing out-of-vocabulary words and as a method for lexicon compression. As the relationship between a string of letters and a string of phonemes representing its pronunciation for many languages is not trivial, we discuss two alignment procedures,

Norbert Broeker

This paper presents a multidimensional Dependency Grammar (DG), which decouples the dependency tree from word order, such that surface ordering is not determined by traversing the dependency tree. We develop the notion of a \emph{word order domain structure}, which is linked but structurally dissimilar to the syntactic dependency tree. We then discuss the im

Sunghwan Rim, Soo-Young Lee, Eui-Soon Yim, C. H. Lee

Generic one-parameter billiards are studied both classically and quantally. The classical dynamics for the billiards makes a transition from regular to fully chaotic motion through intermediary soft chaotic system. The energy spectra of the billiards are computed using finite element method which has not been applied to the euclidean billiard. True generic q

Edward A. Baltz, Joakim Edsjo

Supersymmetric neutralinos are one of the most promising candidates for the dark matter in the Universe. If they exist, they should make up some fraction of the Milky Way halo. We investigate the fluxes of positrons expected at the Earth from neutralino annihilation in the halo. Positron propagation is treated in a diffusion model including energy loss. The

Jonathan E. Grindlay

The detection of x-ray afterglows of gamma-ray burst (GRB) sources has enabled the optical discovery that GRBs are at cosmological distances, which confirms that the enormous luminosities required must produce a relativistically expanding fireball. It is not yet clear if this expansion is quasi-spherical or beamed, or if the beaming differs between the promp

P. Bloser, J. Grindlay, T. Narita, F. Harrison

We report results of an experiment conducted in May 1997 to measure CdZnTe background and background reduction schemes in space flight conditions similar to those of proposed hard X-ray astrophysics missions. A 1 cm^2 CdZnTe detector was placed adjacent to a thick BGO anticoincidence shield and flown piggybacked onto the EXITE2 scientific balloon payload. Th

E. V. Gotthelf, W. Zhang, F. E. Marshall, J. Middleditch

The supernova remnant N157B (30 Dor B, SNR 0539-69.1, NGC 2060), located in the Tarantula Nebula of the Large Magellanic Cloud, has long been considered a possible Crab-like remnant. This hypothesis has been confirmed, quite spectacularly, with the discovery of PSR J0537-6910, the remarkable 16 ms X-ray pulsar in N157B. PSR J0537-6910 is the most rapidly spi

Pranab Ghosh

We investigate the viscous stability of thin, Keplerian accretion disks in regions where general relativistic (GR) effects are essential. For gas pressure dominated (GPD) disks, we show that the Newtonian conclusion that such disks are viscously stable is reversed by GR modifications in the behaviors of viscous stress and surface density over a significantly

Mario Livio

It is shown that, contrary to an existing claim, the near equality between the lifetime of the sun and the timescale of biological evolution on earth does not necessarily imply that extraterrestrial civilizations are exceedingly rare. Furthermore, on the basis of simple assumptions it is demonstrated that a near equality between these two timescales may be t

B. M. Peterson, A. J. Barth, P. Berlind, R. Bertram

We present the results of three years of ground-based observations of the Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield optical continuum and broad-line H-beta light curves for a total of eight years. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this eight-year

Roy Maartens

Recently a covariant approach to cold matter universes in the zero-shear hypersurfaces (or longitudinal) gauge has been developed. This approach reveals the existence of an integrability condition, which does not appear in standard non-covariant treatments. A simple derivation and generalization of the integrability condition is given, based on showing that

R. Ramachandran, A. A. Deshpande, C. Indrani

We report here our observations at 35 MHz and 327 MHz made in the direction of the Gamma Ray pulsar Geminga. Based on the observed absence of any significant pulsed emission from this source above our detection thresholds at the two frequencies, we obtain useful upper-limits for the average flux to be 75-100 mJy at 35 MHz, and 0.2-0.3 mJy at 327 MHz. We disc

M. Ostrowski

Theoretical concepts ofn cosmic ray particle acceleration at relativistic plasma flows -- shocks and shear layers -- are reviewed. We begin with a discussion of mildly relativistic shock waves. The role of oblique field configurations and field perturbations in forming the particle energy spectrum and changing the acceleration time scale is considered. Then,

R. F. Peletier, R. de Grijs

We have determined a dust-free colour-magnitude (CM) relation for spiral galaxies, by using I-K colours in edge-on galaxies above the plane. We find that the scatter in this relation is small and approximately as large as can be explained by observational uncertainties. The slope of the near-IR CM relation is steeper for spirals than for elliptical galaxies.

J. Siebert, W. Brinkmann, S. A. Laurent-Muehleisen, M. Matsuoka

We present recent X-ray observations of intermediate BL Lac objects (IBLs), i.e. BL Lacs which are located between high-energy and low-energy peaked BL Lac objects with respect to alpha_rx. We briefly discuss the statistical properties of IBLs from the RGB sample and then focus on a detailed broad band spectral analysis of two objects, namely 1424+2401 and 1

Kotaro Kohno, Ryohei Kawabe, Baltasar Vila-Vilaro

We present high resolution (3" - 5") observations of CO(1-0) and HCN(1-0) emission from the circumnuclear star forming ring in the barred spiral galaxy NGC 6951, a host of a type-2 Seyfert, using the Nobeyama Millimeter Array and 45 m telescope. We find that most of the HCN emission is associated with the circumnuclear ring, where vigorous star forma

Sharon M. Morsink, Luigi Stella

General relativity predicts that a rotating body produces a frame-dragging (or Lense-Thirring) effect: the orbital plane of a test particle in a non-equatorial orbit precesses about the body's symmetry axis. In this paper we compute the precession frequencies of circular orbits around rapidly rotating neutron stars for a variety of masses and equations o

James Theiler, Jeff Bloch

A method is presented for estimating the background at a given location on a sky map by interpolating the estimated background from a set of concentric annuli which surround this location. If the background is nonuniform but smoothly varying, this method provides a more accurate (though less precise) estimate than can be obtained with a single annulus. Sever

Sergey N. Solodukhin

The product space configuration $AdS_2\times S_2$ (with $l$ and $r$ being radiuses of the components) carrying the electric charge $Q$ is demonstrated to be an exact solution of the semiclassical Einstein equations in presence of the Maxwell field. If the logarithmic UV divergences are absent in the four-dimensional theory the solution we find is identical t

C. P. Bidinosti, W. N. Hardy, D. A. Bonn, Ruixing Liang

We present measurements of the magnetic field dependence of the penetration depth Lambda(H) for untwinned YBa_2Cu_3O_6.95 for temperatures from 1.2 to 70 K in dc fields up to 42 gauss and directions 0, 45 and 90 degrees with respect to the crystal b-axis. The experiment uses an ac susceptometer with fields applied parallel to the ab-plane of thin platelet sa

M. Franz

Theory of quasiparticle transport in the mixed state of a d-wave superconductor is developed under the assumption of disordered vortex array. A novel universal regime is identified at fields above H*= c*H_{c2}(T/T_c)^2, characterized by a field-independent longitudinal thermal conductivity. It is argued that this behavior is responsible for the high-field pl

B. Z. Kopeliovich, A. Schaefer, A. V. Tarasov

The density of gluons produced in the central rapidity region of a heavy ion collision is poorly known. We investigate the influence of the effects of quantum coherence on the transverse momentum distribution of photons and gluons radiated by a quark propagating through nuclear matter. We describe the case that the radiation time substantially exceeds the nu

A. Filippetti, W. E. Pickett, B. M. Klein

CrN is observed to undergo a paramagnetic to antiferromagnetic transition accompanied by a shear distortion from cubic NaCl-type to orthorhombic structure. Our first-principle plane wave and ultrasoft pseudopotential calculations confirm that the distorted antiferromagnetic phase with spin configuration arranged in double ferromagnetic sheets along [110] is

M. P. Lilly, K. B. Cooper, J. P. Eisenstein, L. N. Pfeiffer

Magneto-transport experiments on high mobility two-dimensional electron gases in GaAs/AlGaAs heterostructures have revealed striking anomalies near half-filling of several spin-resolved, yet highly excited, Landau levels. These anomalies include strong anisotropies and non-linearities of the longitudinal resistivity rho_xx which commence only below about 150

Christopher Smith

The treatment of elastic final state interactions (FSI) under a symmetry group is presented. The proposed model is based on Watson's theorem, i.e. on symmetry properties of the S-matrix and on its unitarity. This theorem provides an easy way to introduce rescattering effects by defining final state interactions mixing matrices. A symmetry group fixes the

S. Kretzer, I. Schienbein

We perform an analysis of semi-inclusive production of charm (D-mesons) in neutral current (NC) and charged current (CC) deep inelastic scattering (DIS) at full O(alpha_s^1). Our calculation is based on the heavy quark scheme developed by Aivazis, Collins, Olness and Tung (ACOT) where we include an O(alpha_s^1) calculation of quark scattering contributions f

Mikhail Plyushchay

The class of relativistic spin particle models reveals the `quantization' of parameters already at the classical level. The special parameter values emerge if one requires the maximality of classical global continuous symmetries. The same requirement applied to a non-relativistic particle with odd degrees of freedom gives rise to supersymmetric quantum m

Yungui Gong

The density perturbation during inflation seeds the large scale structure. We consider both new inflation-type and chaotic inflation-type potentials in the framework of Einstein-Brans-Dicke gravity. The density perturbation gives strong constraints on the parameters in these potentials. For both potentials, the constraints are not much different from those o

V. Karimipour

Using the matrix product formalism we formulate a natural p-species generalization of the asymmetric simple exclusion process. In this model particles hop with their own specific rate and fast particles can overtake slow ones with a rate equal to their relative speed. We obtain the algebraic structure and study the properties of the representations in detail

S. N. Gninenko, N. V. Krasnikov

It is shown that the non-zero transition magnetic moment ($μ_{tran}$) between the sterile neutrino ($ν_{s}$) and the muon neutrino ($ν_μ$) could be effectively searched for via the Primakoff effect, in the process of $ν_μ Z \to ν_{s}Z$ conversion in the external Coulomb field of a nucleus $Z$, with the subsequent $ν_{s}\to ν_μ + γ$ decay. From the recent res

S. Fajfer, S. Prelovsek, P. Singer

The short-distance contribution due to the $c\to uγ$ penguin as well as long-distance contributions are considered in an analysis of $D\to Vγ$ decays, the latter being dominant. The matrix elements for nine $D\to Vγ$ transitions are calculated using a hybrid model which combines heavy quark effective theory and the chiral Lagrangian. We present the expected

ZEUS Collaboration

Exclusive production of $ρ^0$ and $J/ψ$ mesons in e^+ p collisions has been studied with the ZEUS detector in the kinematic range $0.25 < Q^2 < 50 GeV^2, 20 < W < 167 GeV$ for the $ρ^0$ data and $2 < Q^2 < 40 GeV^2, 50 < W < 150 GeV$ for the $J/ψ$ data. Cross sections for exclusive $ρ^0$ and $J/ψ$ production have been measured as a function of $Q^2, W$ and $

E. Lopez, B. Ormsby

Using a six-orientifold, fourbranes and four fivebranes in type IIA string theory we construct $\mathcal{N}$=1 supersymmetric gauge theories in four dimensions with product group $SU(M)\times SO(N)$ or $SU(M)\times Sp(2N)$, a bifundamental flavor and quarks. We obtain the Seiberg dual for these theories and rederive it via branes. To obtain the complete dual

Christopher L. Taylor, Henry A. Kobulnicky, Evan D. Skillman

We present 12CO 1-0 observations of eleven low luminosity M_B > -18), HI--rich dwarf galaxies. Only the three most metal-rich galaxies, with 12+log(O/H) ~ 8.2, are detected. Very deep CO spectra of six extremely metal-poor systems (12+log(O/H) < 7.5) yield only low upper limits on the CO surface brightness, I_CO < 0.1 K km/s. Three of these six have never be

Kiwoon Choi, Hang Bae Kim, Hyungdo Kim

We examine the stabilization of the two typical moduli, the length $ρ$ of the eleventh segment and the volume $V$ of the internal six manifold, in compactified heterotic $M$-theory. It is shown that, under certain conditions, the phenomenologically favored vacuum expectation values of $ρ$ and $V$ can be obtained by the combined effects of multi-gaugino conde

Yishen Li, Wen-Xiu Ma

Binary nonlinearization of AKNS spectral problem is extended to the cases of higher-order symmetry constraints. The Hamiltonian structures, Lax representations, $r$-matrices and integrals of motion in involution are explicitly proposed for the resulting constrained systems in the cases of the first four orders. The obtained integrals of motion are proved to

S. S. Sannikov, A. A. Stanislavsky

The goal of this message is to calculate radiative corrections to the Sommerfeld fine structure constant in the framework of a new QED in which particles are described by bilocal fields. The bare constant is 1/136 where 136 is a dimension of the dynamical group of the bihamiltonian system underlying the suggested elementary particle theory. Our calculations

E. A. Kolganova, A. K. Motovilov

A mechanism of disappearance and formation of the Efimov levels of the helium ^4He trimer is studied when the force of the interatomic interaction is changed. It is shown that these levels arise from virtual levels which are in turn formed from (quasi)resonances settled on the real axis. The resonances including virtual levels are calculated by the method ba

Hiroaki Kouno, Manabu Nakai, Akira Hasegawa, Masahiro Nakano

The quantum hadrodynamics are studied by using non-perturbative renormalization group equations. Approximate discrete gamma_5-symmetry is studied. It is shown that the contributions of one-loop diagrams are important for effective potential. A relation between the local-potential approximation and the usual Hartree approximation is discussed. The local-poten

F. V. De Blasio, O. Elgaroy

The microscopic structure of an isolated vortex line in superfluid neutron star matter is studied by solving the Bogoliubov-de Gennes equations. Our calculation, which is the starting point for a microscopic calculation of pinning forces in neutron stars, shows that the size of the vortex core varies differently with density, and is in general smaller than a

Kei Iida, Katsuhiko Sato

The influence of the presence of hyperons in dense hadronic matter on the quantum nucleation of quark matter is examined at low temperatures relevant to neutron star cores. We calculate the equation of state and the composition of matter before and after deconfinement by using a relativistic mean-field theory and an MIT bag model, respectively; the case in w

Daniel M. Elton, Dmitri Vassiliev

In the first part of the paper we give a tensor version of the Dirac equation. In the second part we formulate and analyse a simple model equation which for weak external fields appears to have properties similar to those of the 2--dimensional Dirac equation.

M. X Shao, Z. Y Zhu

The Weil&#39;s integrality condition of prequantization line bundle is generalized to phase space with boundaries. The proofs of both necessity and sufficiency are given. It is pointed out via the method of topological current that Weil&#39;s integrality condition is closely connected with the summation of index of isolated singular points of sections of pre

C. Quesne, N. Vansteenkiste

The C_λ-extended oscillator algebra is generated by {1,a,a^{\dagger},N,T}, where T is the generator of the cyclic group C_λ of order λ. It can be realized as a generalized deformed oscillator algebra (GDOA). Its unirreps can thus be exhibited using the representation theory of GDOAs and their carrier space show a Z_λ grading structure. Within its infinite-di

M. Irac-Astaud, C. Quesne

Some time ago, Rideau and Winternitz introduced a realization of the quantum algebra su_q(2) on a real two-dimensional sphere, or a real plane, and constructed a basis for its representations in terms of q-special functions, which can be expressed in terms of q-Vilenkin functions, and are related to little q-Jacobi functions, q-spherical functions, and q-Leg

Marc Rieffel, Albert Schwarz

One can describe an $n$-dimensional noncommutative torus by means of an antisymmetric $n\times n$-matrix $θ$. We construct an action of the group $SO(n,n|\bf Z)$ on the space of antisymmetric matrices and show that, generically, matrices belonging to the same orbit of this group give Morita equivalent tori. Some applications to physics are sketched.

Marcos Marino, Gregory Moore

We explicitly evaluate the low energy coupling $F_g$ in a $d=4,\mathcal{N}=2$ compactification of the heterotic string. The holomorphic piece of this expression provides the information not encoded in the holomorphic anomaly equations, and we find that it is given by an elementary polylogarithm with index $3-2g$, thus generalizing in a natural way the known

Richard A. Battye, Paul M. Sutcliffe

It has been suggested recently that knots might exist as stable soliton solutions in a simple three-dimensional classical field theory, opening up a wide range of possible applications in physics and beyond. We have re-examined and extended this work in some detail using a combination of analytic approximations and sophisticated numerical algorithms. For cha

Christiaan Hofman, Erik Verlinde, Gysbert Zwart

We calculate the Hamiltonian of a compactified D4-brane, with general fluxes and moduli, and find the BPS-mass. The results are invariant under the complete U-duality SO(5,5,Z).