May 2000 arXiv papers — page 9

J. Gerssen, K. Kuijken, M. R. Merrifield

Various processes have been proposed to explain how galaxy discs acquire their thickness. A simple diagnostic for ascertaining this ``heating'' mechanism is provided by the ratio of the vertical to radial velocity dispersion components. In a previous paper we have developed a technique for measuring this ratio, and demonstrated its viability on the S

R. G. Kaptein, J. J. M. in 't Zand, E. Kuulkers, F. Verbunt

We report the first-time detection of a type-I X-ray burst from a position that is consistent with that of 1RXS J171824.2-402934. The detection was made on Sep 23, 1996, with the Wide Field Cameras on board the BeppoSAX satellite. The burst had a peak intensity of 1.3 Crab units in 2 to 28 keV and is relatively long (at least 3.5 min). Analysis of the burst

Hiroshi Tsunemi, Emi Miyata, Bernd Aschenbach, Junko Hiraga

Recently, COMPTEL has detected $γ$-rays of 1157 keV from $^{44}$Ti in the direction of the SNR RX J0852$-$4622 (Iyudin et al. 1998). Since $^{44}$Ti is a product of explosive nucleosynthesis and its half lifetime $τ\sb{1/2}$ is about 60 yrs, RX J0852$-$4622 must be a young supernova remnant and radiation is dominated by the ejecta rather than by interstellar

S. Borgani, M. Bernardi, L. N. da Costa, G. Wegner

We present an analysis of the ENEAR sample of peculiar velocities of elliptical galaxies, obtained with D_n-σdistances. We use the velocity correlation function to analyze the statistics of the field-object's velocities, while the analysis of the cluster data is based on the estimate of their rms peculiar velocity, Vrms. The statistics of the model veloc

Philippe Brax, Jerome Martin

It is shown that any realistic model of quintessence should be based on Supergravity (SUGRA) since the value of the quintessence field on the attractor is approximately the Planck mass. Under very general assumptions, the typical shape of a SUGRA tracking potential is derived. Cosmological implications are investigated. In particular, it is demonstrated that

Sara L. Ellison, Antoinette Songaila, Joop Schaye, Max Pettini

We have obtained an exceptionally high S/N, high resolution spectrum of the gravitationally lensed quasar Q1422+231 in order to investigate the metal enrichment of the IGM. A column density distribution function (CDDF) is determined for CIV, which is well fit by a power law with index 1.44 +/- 0.05. Once a correction for incompleteness is applied, we find th

A. Schroeder, R. C. Kraan-Korteweg, G. A. Mamon

We discuss the possibilities of extragalactic large-scale studies behind the Zone of Avoidance (ZOA) using complementary multi-wavelength data from optical, systematic blind HI, and near-infrared (NIR) surveys. Applying these data to the NIR Tully-Fisher relation permits the mapping of the peculiar velocity field across the ZOA. Here, we present results of a

Francesco Miniati, Dongsu Ryu, T. W. Jones, Hyesung Kang

We investigate the dynamical importance of a newly recognized possible source of significant feedback generated during structure formation; namely cosmic ray (CR) pressure. We present evidence for the existence of numerous shocks in the hot gas of galaxy clusters (GCs). We employ for the first time an explicit numerical treatment of CR acceleration and trans

Francesco Miniati, Dongsu Ryu, Hyesung Kang, T. W. Jones

We have examined the properties of shock waves in simulations of large scale structure formation for two cosmological scenarios (a SCDM and a LCDM with Omega =1). Large-scale shocks result from accretion onto sheets, filaments and Galaxy Clusters (GCs) on a scale of circa 5 Mpc/h in both cases. Energetic motions, both residual of past accretion history and d

Rosalba Perna, Anthony Aguirre

The amount and properties of high-redshift galactic and intergalactic (IG) dust are largely unknown, but could be investigated using multi-wavelength photometry of high-z objects that have a known intrinsic spectrum. Observations of gamma-ray burst (GRB) afterglows appear to support the theoretical model of an adiabatic blast wave expanding into an external

Craig J. Hogan

It is shown that the standard cosmological model predicts {\it ab initio} generation of large-scale but very small-amplitude cosmic magnetic fields at the epoch of recombination of the primeval plasma. Matter velocities dominated by coherent flows on a scale $L\approx 50h^{-1}(1+z)^{-1}$ Mpc lead to a dipole of radiation flux in the frame of the moving matte

F. Natali, L. Di Fino, G. Natali

Using the B-I color index in the radial photometry of M51, applied to defined azimuthal sectors, we reveals asymmetries in the shape of the density pattern of the galactic arms. The anomalous shape is present only in the side close to the companion and not in the far side. Two more non-interacting check-spirals do not show similar behaviour. The anomalous sa

G. Umana, P. F. L. Maxted, C. Trigilio, R. P. Fender

In this paper we present high spatial resolution radio images of the puzzling binary system beta Lyrae obtained with MERLIN at 5 GHz. We find a nebula surrounding the binary with a brightness temperature of 11000+-700K approximately 40AU across. This definitively confirms the thermal origin of the radio emission, which is consistent with emission from the wi

David J. Gross, Nikita A. Nekrasov

We study some non-perturbative aspects of noncommutative gauge theories. We find analytic solutions of the equations of motion, for noncommutative U(1) gauge theory, that describe magnetic monopoles with a finite tension string attached. These solutions are non-singular, finite and sourceless. We identify the string with the projection of a D-string ending o

Eunsang Kim, Hoil Kim, Chang-Yeong Lee

In this paper, we construct gauge bundles on a noncommutative toroidal orbifold $T^4_θ/Z_2$. First, we explicitly construct a bundle with constant curvature connections on a noncommutative $T^4_θ$ following Rieffel's method. Then, applying the appropriate quotient conditions for its $Z_2$ orbifold, we find a Connes-Douglas-Schwarz type solution of matrix

J. A. S. Lima, J. S. Alcaniz

New limits on the cosmic equation of state are derived from age measurements of three recently reported old high redshift galaxies (OHRG). The results are based on a flat FRW type cosmological model driven by nonrelativistic matter plus a smooth component parametrized by its equation of state $p_{x} = ωρ_{x}$ ($ω\geq -1$). The range of $ω$ is strongly depend

Charles D. Dermer

The hypothesis that ultra-high energy (>~ 10^19 eV) cosmic rays (UHECRs) are accelerated by gamma-ray burst (GRB) blast waves is assumed to be correct. Implications of this assumption are then derived for the external shock model of gamma-ray bursts. The evolving synchrotron radiation spectrum in GRB blast waves provides target photons for the photomeson pro

J. Schaffner-Bielich, A. Gal

The hyperon-hyperon potentials due to a recent SU(3) Nijmegen soft-core potential model are incorporated within a relativistic mean field calculation of strange hadronic matter. We find considerably higher binding energy in bulk matter compared to several recent calculations which constrain the composition of matter. For small strangeness fractions, matter i

D. L. Haycock, P. M. Alsing, I. H. Deutsch, J. Grondalski

We observe the quantum coherent dynamics of atomic spinor wavepackets in the double well potentials of a far-off-resonance optical lattice. With appropriate initial conditions the system Rabi oscillates between the left and right localized states of the ground doublet, and at certain times the wavepacket corresponds to a coherent superposition of these mesos

M. Rampp, H. -Th. Janka

We present a spherically symmetric, Newtonian core-collapse simulation of a 15 solar mass star with a 1.28 solar mass iron core. The time-, energy-, and angle-dependent transport of electron neutrinos and antineutrinos was treated with a new code which iteratively solves the Boltzmann equation and the equations for neutrino number, energy and momentum to ord

Yosef Ashkenazy, Plamen Ch. Ivanov, Shlomo Havlin, Chung-K. Peng

We propose an approach for analyzing signals with long-range correlations by decomposing the signal increment series into magnitude and sign series and analyzing their scaling properties. We show that signals with identical long-range correlations can exhibit different time organization for the magnitude and sign. We find that the magnitude series relates to

R. Mélin

I consider a theoretical description of recent experiments on doping the spin-Peierls compound CuGeO$_3$ and the Haldane gap compounds PbNi$_2$V$_2$O$_8$ and Y$_2$BaNiO$_5$. The effective theory is the one of randomly distributed spin-$1/2$ moments interacting with an exchange decaying exponentially with distance. The model has two phases in the (doping, int

E. J. Copeland, N. J. Nunes, F. Rosati

Scalar field models of quintessence typically require that the expectation value of the field today is of order the Planck mass, if we want them to explain the observed acceleration of the Universe. This suggests that we should be considering models in the context of supergravity. We discuss a particular class of supergravity models and analyze their behavio

James Amundson, Carl Schmidt, Wu-Ki Tung, Xiaoning Wang

Charm final states in deep inelastic scattering constitute $\sim 25%$ of the inclusive cross-section at small $x$ as measured at HERA. These data can reveal important information on the charm and gluon structure of the nucleon if they are interpreted in a consistent perturbative QCD framework which is valid over the entire energy range from threshold to the

Steve B. Howell, Lorne A. Nelson, Saul Rappaport

We critically examine the basic paradigm for the origin of the 2-3 hr period gap in cataclysmic variables (CVs). We carry out an extensive population synthesis study of CVs starting from ~ 3 x 10^6 primordial binaries, and evolving some ~ 2 x 10^4 surviving systems through their CV phase. In particular we study current-epoch distributions of CVs in the $\dot

Daniel C. Hong, Joseph A. Both

We present a thermo-statistical model of popcorn production and propose a way to control the final size of the popcorn by monitoring only the chamber pressure.

Robert H. Brandenberger, Jerome Martin

We calculate the spectrum of density fluctuations in models of inflation based on a weakly self-coupled scalar matter field minimally coupled to gravity, and specifically investigate the dependence of the predictions on modifications of the physics on length scales smaller than the Planck length. These modifications are encoded in terms of modified dispersio

Mark Bowick, Alex Travesset

We study the formulation of bond-orientational order in an arbitrary two dimensional geometry. We find that bond-orientational order is properly formulated within the framework of differential geometry with torsion. The torsion reflects the intrinsic frustration for two-dimensional crystals with arbitrary geometry. Within a Debye-Huckel approximation, torsio

P. Shukla, A. K. Mohanty, S. K. Gupta

The rate of dynamical growth of the hadron bubbles in a supercooled baryon free quark-gluon plasma, is evaluated by solving the equations of relativistic fluid dynamics in all regions. For a non-viscous plasma, this dynamical growth rate is found to depend only on the range of correlation $ξ$ of order parameter fluctuation, and the radius $R$ of the critical

Stepehn L. Adler

Lisi, Marrone, and Montanino have recently proposed a test for quantum gravity induced decoherence effects in neutrino oscillations observed at Super-Kamiokande. We comment here that their equations have the same qualitative form as the energy conserving objective state vector reduction equations discussed by a number of authors. However, using the Planckian

N. G. Stefanis, W. Schroers, H. -Ch. Kim

We develop and discuss in technical detail an infrared-finite factorization and optimized renormalization scheme for calculating exclusive processes, which enables the inclusion of transverse degrees of freedom without entailing suppression of calculated observables, like form factors. This is achieved by employing an analytic, i.e., infrared stable, running

Davide Controzzi, Fabian H. L. Essler, Alexei M. Tsvelik

We calculate the optical conductivity of one-dimensional Mott insulators at low energies using a field theory description. The square root singularity at the optical gap, characteristic of band insulators, is generally absent and appears only at the Luther-Emery point. We also show that only few particle processes contribute significantly to the optical cond

Masayuki Kawakita

We deal with a divisorial contraction in dimension 3 which contracts its exceptional divisor to a smooth point. We prove that any such contraction can be obtained by a suitable weighted blow-up.

X. Campi, H. Krivine, N. Sator

We predict that self-bound clusters of particles exist in the supercritical phase of simple fluids. These clusters, whose internal temperature is lower than the global temperature of the system, define a percolation line that starts at the critical point. This line should be physically observable. Possible experiments showing the validity of these prediction

Dietmar G. Fischer, Matthias Freyberger

We discuss single adaptive measurements for the estimation of mixed quantum states of qubits. The results are compared to the optimal estimation schemes using collective measurements. We also demonstrate that the advantage of collective measurements increases when the degree of mixing of the quantum states increases.

M. Rybczynski, Z. Wlodarczyk, G. Wilk

We argue that atmospheric cascades can be regarded as example of the self-organized criticality and studied by using Levy flights and nonextensive approach. It allows us to understand the scale-invariant energy fluctuations inside cascades in a natural way.

M. Rybczynski, Z. Wlodarczyk, G. Wilk

The hypothesis is discussed that muon bundles of extremaly high multiplicity observed recently by ALEPH detector (in the dedicated cosmic-ray run) can originate from the strangelets colliding with the atmosphere.

V. I. Alexeev, E. G. Bessonov

Generation of long wavelength edge radiation along directions nearly coincident with the axes of straight sections of storage rings and synchrotrons is discussed. The removal of destructive interference from the superimposed edge radiation patterns of a straight section on the synchrotron "Pakhra" has been observed experimentally.

Andrés Aguado

The melting-like transition in potasium clusters K_N, with N=20, 55, 92 and 142, is studied by using an orbital-free density-functional constant-energy molecular dynamics simulation method, and compared to previous theoretical results on the melting-like transition in sodium clusters of the same sizes. Melting in potasium and sodium clusters proceeds in a si

M. M. G. Krishna, Joseph Samuel, Supurna Sinha

We study the diffusion of Brownian particles on the surface of a sphere and compute the distribution of solid angles enclosed by the diffusing particles. This function describes the distribution of geometric phases in two state quantum systems (or polarised light) undergoing random evolution. Our results are also relevant to recent experiments which observe

Joseph Samuel

This letter is a critique of Barbero's constrained Hamiltonian formulation of General Relativity on which current work in Loop Quantum Gravity is based. While we do not dispute the correctness of Barbero's formulation of general relativity, we offer some criticisms of an aesthetic nature. We point out that unlike Ashtekar's complex SU(2) connecti

J. Maurice Rojas

We present some new and recent algorithmic results concerning polynomial system solving over various rings. In particular, we present some of the best recent bounds on: (a) the complexity of calculating the complex dimension of an algebraic set, (b) the height of the zero-dimensional part of an algebraic set over C, and (c) the number of connected components

Joseph Samuel

This paper discusses the implementation of diffeomorphism invariance in purely Hamiltonian formulations of General Relativity. We observe that, if a constrained Hamiltonian formulation derives from a manifestly covariant Lagrangian, the diffeomorphism invariance of the Lagrangian results in the following properties of the constrained Hamiltonian theory: the

Kazuyuki Furuuchi

Projections play crucial roles in the ADHM construction on noncommutative $\R^4$. In this article a framework for the description of equivalence relations between projections is proposed. We treat the equivalence of projections as ``gauge equivalence'' on noncommutative space. We find an interesting application of this framework to the study of U(2)

Gideon Alexander, Edward Sarkisyan

We report on a study aimed to explore the dependence of the genuine multiparticle correlations on the number of sources when the influence of other possible factors during multihadron production are avoided. The analysis utilised the normalised cumulants calculated in three-dimensional phase space of the reaction ee -> Z -> hadrons using a large Monte Carlo

Takashi Tamaki, Kei-ichi Maeda

We study about an approximation method of the Hawking radiation. We analyze an massless scalar field in exotic black hole backgrounds models which have peculiar properties in black hole thermodynamics (monopole black hole in SO(3) Einstein-Yang-Mills-Higgs system and dilatoic black hole in Einstein-Maxwell-dilaton system). A scalar field is assumed not to be

Shin'ichi Nojiri, Sergei D. Odintsov, Sachiko Ogushi

d3 and d5 maximally SUSY gauged supergravity is considered in the parametrization (flow) of full scalar coset where the kinetic term for scalars takes the standard field theory form and the bulk potential is an arbitrary one subject to consistent parametrization. From such SG duals we calculate d2 and d4 holographic conformal anomaly which depends on bulk sc

Kanehisa Takasaki

By replacing the ordinary product with the so called $\star$-product, one can construct an analogue of the anti-self-dual Yang-Mills (ASDYM) equations on the noncommutative $\bbR^4$. Many properties of the ordinary ASDYM equations turn out to be inherited by the $\star$-product ASDYM equation. In particular, the twistorial interpretation of the ordinary ASDY

K. Hirotani

We study the gamma-ray emissions from an outer-magnetospheric potential gap around a rotating neutron star. Migratory electrons and positrons are accelerated by the electric field in the gap to radiate copious gamma-rays via curvature process. Some of these gamma-rays materialize as pairs by colliding with the X-rays in the gap, leading to a pair production

Isaac Chuang

The clock synchronization problem is to determine the time difference $Δ$ between two spatially separated clocks. When message delivery times between the two clocks are uncertain, $O(2^{2n})$ classical messages must be exchanged between the clocks to determine $n$ digits of $Δ$. On the other hand, as we show, there exists a quantum algorithm to obtain $n$ di

Alexander K. Popov, Alexander S. Bayev

We show that atoms from wide velocity interval can be concurrently involved in Doppler-free two-photon resonant far from frequency degenerate four-wave mixing with the aid of auxiliary electromagnetic field. This gives rise to substantial enhancement of the output radiation generated in optically thick medium. Numerical illustrations addressed to typical exp

D. A. Trifonov

A scheme for construction of uncertainty relations (UR) for n observables and m states is presented. Several lowest order UR are displayed and briefly discussed. For two states |ψ> and |ϕ> and canonical observables the (entangled) extension of Heisenberg UR reads [Δp(ψ)]^2[Δq(ϕ)]^2 + [Δp(ϕ)]^2[Δq(ψ)]^2 \geq 1/2. Some possible applications of the new inequali

Krzysztof Dzierzega, Udo Volz, Gillian Nave, Ulf Griesmann

Branching fractions were measured for electric dipole transitions from the 5p upper levels to the 5s levels in neutral krypton atoms. The measurements were made with a wall-stabilized electric arc and a 2m monochromator for the spectral lines in the visible, and with a hollow cathode lamp and the NIST 2m-Fourier transform spectrometer for the lines in the ne

I. V. Bayak

It is presented the concept of controled nuclear synthesis in top of cone formed by rotational dynamic flow of low-temperature plasma.

Eyvind Aker, Alex Hansen, Knut Jorgen Maloy

This paper reviews recent research results in two-phase flow in porous media obtained by the authors.

Jonny Heiss

Assuming the existence of a Multidirectional Homogeneous and Constant Shower of Elementary Particles (MHCSEP) traveling at light speed in space, several basic laws of physics are derived mainly by geometrical considerations. When placing two bodies in space, obstruction of the MHCSEP creates an attractive force among them that coincides, for two bodies, with

O. Benhar, V. R. Pandharipande, I. Sick

We analyze data on deep inelastic scattering of electrons from the proton using ideas from standard many-body theory involving {\em bound} constituents subject to {\em interactions}. This leads us to expect, at large three-momentum transfer ${\bf{q}}$, scaling in terms of the variable $\tilde{y}=ν-{\bf |q|}$. The response at constant ${\bf |q|}$ scales well

D. Debruyne, J. Ryckebusch, W. Van Nespen, S. Janssen

A fully relativistic model for the description of exclusive (e,e'p) reactions off nuclear targets at high energies and momentum transfers is outlined. It is based on the eikonal approximation for the ejectile scattering wave function and a relativistic mean-field approximation to the Walecka model. Results for ^{12}C(e,e'p) and ^{16}O(e,e'p) diff

Ulrich Heinz, Pierre Scotto

We shortly review recent successes in applying Bose-Einstein interferometry in heavy ion collisions and the proceed to some model calculations for 3-dimensional Bose-Einstein correlation functions in electron-positron collisions at the Z0 pole.

Igor Pavlichenkov, Andrei Shchurenkov

A simple criterion for the ΔI = 4 bifurcation is applied to thirty superdeformed bands in the A~150 mass region. The analysis allows to differentiate between active and inactive for staggering single-particle states. The consideration is based on additivity of nonaxial hexadecapole moment, which plays a key role in the phenomenon.

M. S. Alber, Y. N. Fedorov

The algebraic-geometric approach is extended to study solutions of N-component systems associated with the energy dependent Schrodinger operators having potentials with poles in the spectral parameter, in connection with Hamiltonian flows on nonlinear subvariaties of Jacobi varieties. The systems under study include the shallow water equation and Dym type eq

H. W. Braden

Suppose we have a natural Hamiltonian $H$ of $n$ particles on the line, centre of mass momentum $P$ and a further independent quantity $Q$, cubic in the momenta. If these are each $S_{n}$ invariant and mutually Poisson commute we have the Calogero-Moser system with potential $V={1/6}\sum\limits_{i\neq j}\wp(q_{i}-q_{j}) +const$.

K. Weibert, J. Main, G. Wunner

Harmonic inversion has already been proven to be a powerful tool for the analysis of quantum spectra and the periodic orbit orbit quantization of chaotic systems. The harmonic inversion technique circumvents the convergence problems of the periodic orbit sum and the uncertainty principle of the usual Fourier analysis, thus yielding results of high resolution

Stephen F. Sawin

A version of Kirby calculus for spin and framed three-manifolds is given and is used to construct invariants of spin and framed three-manifolds in two situations. The first is ribbon *-categories which possess odd degenerate objects. This case includes the quantum group situations corresponding to the half-integer level Chern-Simons theories conjectured to g

I. V. Bayak

It is constructed the functor from category of product linear space to category of skew-symmetric tensor space. It is defined and described the bound bundle as analog of a symplex and as basis element of new constructive homology theory.

I. V. Bayak

It is shown that classical Clifford algebras are group algebras of cyclic subgroups of arrowy rermutations. It is established that Euclidean 3-space, Pauli and Dirac algebras and groups of global guage transformations are corollary from the geometry of 8-dimensional vacuum and 9-dimensional cosmos.

I. V. Bayak

It is shown that the groups of automorphisms of Euclidean spaces are isomorphic to the groups of topologic automorphisms of respectively factored arithmetic spaces. In particular, the geometry of Euclidean n-space with positive signature is associated with factorization of n-dimensional arithmetic space into n-dimensional sphere.

I. V. Bayak

It is described the group of arrowy permutations (that is extension of symmetric group) and the consequent process of generation of GL(n) and some its subgroups by this combinatoric group and its subgroups.

Sergey Arkhipov

We construct a geometric version of BRST cohomology complex of a chiral module over a Lie-* algebra using the language of differential graded Lie algebroids in the category of D-modules on a compact curve $X$.

Matthew Nicol, Nikita Sidorov, David Broomhead

Suppose $\{f_1,...,f_m\}$ is a set of Lipschitz maps of $\mathbb{R}^d$. We form the iterated function system (IFS) by independently choosing the maps so that the map $f_i$ is chosen with probability $p_i$ ($\sum_{i=1}^m p_i=1$). We assume that the IFS contracts on average. We give an upper bound for the Hausdorff dimension of the invariant measure induced on

Lee Mosher, Michah Sageev, Kevin Whyte

We develop a battery of tools for studying quasi-isometric rigidity and classification problems for splittings of groups. The techniques work best for finite graphs of groups where all edge and vertex groups are coarse PD groups. For example, if Gamma is a graph of coarse PD(n) groups for a fixed n, if the Bass-Serre tree of Gamma has infinitely many ends, a

Herbert H. H. Homeier

Sequence transformations are important tools for the convergence acceleration of slowly convergent scalar sequences or series and for the summation of divergent series. Transformations that depend not only on the sequence elements or partial sums $s_n$ but also on an auxiliary sequence of so-called remainder estimates $ω_n$ are of Levin-type if they are line

Amir Leshem

In this paper we prove the equiconsistency of ``Every omega_1 tree which is first order definable over H_{omega_1} has a cofinal branch'' with the existence of a Pi^1_1 reflecting cardinal. The proof uses a definable version of Ramsey theorem on aleph_1 which is again equiconsistent with a Pi^1_1 reflecting cardinal. We also prove that the addition o

A. Campillo, F. Delgado, S. M. Gusein-Zade

We discuss a notion of integration with respect to the Euler characteristic in the projectivization $¶{\cal O}_{\C^n,0}$ of the ring ${\cal O}_{\C^n,0}$ of germs of functions on $C^n$ and show that the Alexander polynomial and the zeta-function of a plane curve singularity can be expressed as certain integrals over $¶{\cal O}_{\C^2,0}$ with respect to the Eu

S. V. Ludkovsky

This work is devoted to the investigation of the problem about inverse mapping systems expansions of ultrauniform spaces $X$ using polyhedra over non-Archimedean locally compact fields $\bf L$. Theorems about expansions of complete ultrametric and ultrauniform spaces are proved. Absolute polyhedral expansions and inverse mapping systems of expansions for non

Y. Hara, M. Jimbo, H. Konno, S. Odake

We show that the deformed Virasoro algebra specializes in a certain limit to Lepowsky-Wilson's Z-algebra. This leads to a free field realization of the affine Lie algebra \hat{sl_2} which respects the principal gradation. We discuss some features of this bosonization including the screening current and vertex operators.

L. Chiantini, M. Coppens

For an irreducible projective variety X, we study the family of h-planes contained in the secant variety Sec_k(X), for 0<h<k. These families have an expected dimension and we study varieties for which the expected dimension is not attained; for these varieties, making general consecutive projections to lower dimensional spaces, we do not get the expected sin

Alexander Polishchuk

We present expressions for the Weierstrass zeta-function and related elliptic functions by rapidly converging series. These series arise as triple products in the A-infinity category of an elliptic curve.

Yogish I. Holla, Nitin Nitsure

The complex Lie group GO(2n,C) by definition consists of all complex matrices A of size 2n, such that A times transpose(A) is a non-zero scalar. In this paper we determine explicitly the singular cohomology ring of the classifying space BGO(2n,C) with mod 2 coefficients, in terms of generators and relations. The method consists of analysing a certain derivat

Patricio Gaete

We analyze the relation between the Lagrangian and Hamiltonian BRST symmetry generators for a recently proposed two-dimensional symmetry. In particular it is shown that this symmetry may be obtained from a canonical transformation in the ghost sector in a gauge independent way.

J. J. McKenzie-Smith, D. J. Toms

For the case of a relativistic scalar field at finite temperature with a chemical potential, we calculate an exact expression for the one-loop effective action using the full fourth order determinant and zeta-function regularisation. We find that it agrees with the exact expression for the factored operator and thus there appears to be no mulitplicative anom

Branko Dragovich

New approach to p-adic and adelic strings, which takes into account that not only world sheet but also Minkowski space-time and string momenta can be p-adic and adelic, is formulated. p-Adic and adelic string amplitudes are considered within Feynman&#39;s path integral formalism. The adelic Veneziano amplitude is calculated. Some discreteness of string momen

Shibusa Yuuichirou

We calculate a component of connection superfields and Lorentz superparameter at second order in anticommuting coordinates in terms of the component fields of 11-dimensional on-shell supergravity by using `Gauge completion&#39;. This configuration of superspace holds the $κ$-symmetry for supermembrane Lagrangian and represents 11-dimensional on-shell supergr

Paul S. Aspinwall, Sheldon Katz, David R. Morrison

The F-theory vacuum constructed from an elliptic Calabi-Yau threefold with section yields an effective six-dimensional theory. The Lie algebra of the gauge sector of this theory and its representation on the space of massless hypermultiplets are shown to be determined by the intersection theory of the homology of the Calabi-Yau threefold. (Similar statements

V. N. Baier, V. M. Katkov

The coherent scattering of photon in the Coulomb field (the Delbrück scattering) is considered for the momentum transfer $Δ\ll m$ in the frame of the quasiclassical operator method. In high-energy region this process occurs over rather long distance. The process amplitude is calculated taking into account the multiple scattering of particles of the intermedi

Fumihiro Takayama, Masahiro Yamaguchi

Cosmological issues are examined when gravitino is the lightest superparticle (LSP) and R-parity is broken. Decays of the next lightest superparticles occur rapidly via R-parity violating interaction, and thus they do not upset the big-bang nucleosynthesis, unlike the R-parity conserving case. The gravitino LSP becomes unstable, but its lifetime is typically

Harold W. Fearing, Thomas R. Hemmert, Randy Lewis, Christine Unkmeir

The differential cross sections for $π^- p \to γn$ and $π^+ n \to γp$ are computed up to $O(p^3)$ in heavy baryon chiral perturbation theory (HBChPT). The expressions at $O(p)$ and $O(p^2)$ have no free parameters. There are three unknown parameters at $O(p^3)$, low energy constants of the HBChPT Lagrangian, which are determined by fitting to experimental da

Yasunori Nomura, T. Yanagida

We propose a new U(1) gauge interaction in the bulk in higher dimensional spacetime, which transmits supersymmetry-breaking effects on the hidden brane to the observable our brane. We find that rather small gauge coupling constant of U(1)_{bulk}, $α_{bulk} \simeq 5 \times 10^{-4}$, is required for a successful phenomenology. This result implies the compactif

Bo-Qiang Ma, Ivan Schmidt, Jacques Soffer, Jian-Jun Yang

We present a general analysis of the spin transfer for $Λ$ and $\barΛ$ production in deep-inelastic scattering of polarized charged leptons on the nucleon, and find that the pattern of different behaviors of $Λ$ and $\barΛ$ production observed by the E665 Collaboration suggests the possibility of quark-antiquark asymmetries either in the quark to $Λ$ fragmen

Matthias Burkardt

We use two-dimensional QCD as a toy laboratory to study off-forward parton distributions (OFPDs) in a covariant field theory. Exact expressions (to leading order in $1/N_C$) are presented for OFPDs in this model and are evaluated for some specific numerical examples. Special emphasis is put on comparing the $x>ζ$ and $x<ζ$ regimes as well as on analyzing the

B. Bolder, T. Struckmann, G. S. Bali, N. Eicker

For lattice QCD with two sea quark flavours we compute the static quark antiquark potential V(R) in the regime where string breaking is expected. In order to increase statistics, we make full use of the lattice information by including all lattice vectors R to any possible lattice separation in the infrared regime. The corresponding paths between the lattice

M. Faber, J. Greensite, S. Olejnik

Starting from the strong-coupling SU(2) Wilson action in D=3 dimensions, we derive an effective, semi-local action on a lattice of spacing L times the spacing of the original lattice. It is shown that beyond the adjoint color-screening distance, i.e. for $L \ge 5$, thin center vortices are stable saddlepoints of the corresponding effective action. Since the

V. A. Kudryavtsev, N. J. C. Spooner, D. R. Tovey, J. W. Roberts

We report a study of CsI(Tl) scintillator to assess its applicability in experiments to search for dark matter particles. Measurements of the mean scintillation pulse shapes due to nuclear and electron recoils have been performed. We find that, as with NaI(Tl), pulse shape analysis can be used to discriminate between electron and nuclear recoils down to 4 ke

G. Brooijmans

The general strategy, as well as channel-specific details, applied to the measurement of the top quark mass at the Tevatron in Run I are reviewed, and the combination of the results obtained by the CDF and DO collaborations presented. The accelerator and detector upgrades for Run II are described, and expected improvements in the systematic uncertainties on

Y. Kulchitsky

The method of extraction of the e/h ratio for an electromagnetic compartment of a combined calorimeter is suggested and the non-compensation was determined. The results agree with the Monte Carlo prediction and results of the weighting method for electromagnetic compartment of combined calorimeter. The new easy method of a hadronic energy reconstruction for

Clarissa-Marie Claudel

It is a common assumption amongst astronomers that, in the determination of the distances of remote sources from their apparent brightness, the cumulative gravitational lensing due to the matter in all the galaxies is the same, on average, as if the matter were uniformly distributed throughout the cosmos. The validity of this assumption is considered here by

Joseph Samuel, Rajaram Nityananda

Fermi Transport is useful for describing the behaviour of spins or gyroscopes following non-geodesic, timelike world lines. However, Fermi Transport breaks down for null world lines. We introduce a transport law for polarisation vectors along non-geodesic null curves. We show how this law emerges naturally from the geometry of null directions by comparing po

E. Sergio Santini

In this thesis the Bohm-de Broglie interpretation of quantum mechanics is applied to canonical quantum gravity. It is shown that, irrespective of any regularization or choice of factor ordering of the Wheeler-DeWitt equation, the unique relevant quantum effect which does not break spacetime is the change of its signature from lorentzian to euclidean. The oth

V Guruprasad

I show that a cumulative contraction or expansion must result from repetitive tidal action in a curved stress field, depending on the direction of the curvature. The resulting expansion of solid materials onboard deep space probes and the corresponding contraction on earth would be of the right magnitude to account for all aspects of the Pioneer anomaly, lea

Markus Walther

Reduplication, a central instance of prosodic morphology, is particularly challenging for state-of-the-art computational morphology, since it involves copying of some part of a phonological string. In this paper I advocate a finite-state method that combines enriched lexical representations via intersection to implement the copying. The proposal includes a r