February 1999 arXiv papers — page 10

G. Quznetsov

The Dirac equation is deduced from the probability properties by the Poincare group transformations.

L. Zhou, J. Piekarewicz

We compute for the first time the decay width of lambda-hypernuclei in a relativistic mean-field approximation to the Walecka model. Due to the small mass difference between the lambda-hyperon and its decay products---a nucleon and a pion---the mesonic component of the decay is strongly Pauli blocked in the nuclear medium. Thus, the in-medium decay becomes d

H. Heiselberg, M. Hjorth-Jensen

Recent equations of state for dense nuclear matter are discussed with possible phase transitions arising in neutron stars such as pion, kaon and hyperon kondensation, superfluidity and quark matter. Specifically, we treat the nuclear to quark matter phase transition, the possible mixed phase and its structure. A number of numerical calculations of rotating n

V. V. Alekseev, S. N. Cherepnya, L. V. Fil'kov, V. L. Kashevarov

The possibility of observation of supernarrow dibaryons, decay of which into two nucleons forbidden by the Pauli principle, produced in processes of charged pion photoproduction by polarized photons from the deuteron is analyzed. It is shown that the expectable dibaryon yield may exceed the background by a factor of 10--100.

Wellington da Cruz

We prove that the Farey sequences can be express into equivalence classes labeled by a fractal parameter which looks like a Hausdorff dimension $h$ defined within the interval 1 < h < 2. The classes $h$ satisfy the same properties of the Farey series and for each value of $h$ there exists an algebraic equation.

R. Vershynin

Every frame in Hilbert space contains a subsequence equivalent to an orthogonal basis. If a frame is n-dimensional then this subsequence has length (1 - ε) n. On the other hand, there is a frame which does not contain bases with brackets.

R. M. Green

We introduce procellular algebras, so called because they are inverse limits of finite dimensional cellular algebras as defined by Graham and Lehrer. A procellular algebra is defined as a certain completion of an infinite dimensional cellular algebra whose cell datum is of ``profinite type&#39;&#39;. We show how these notions overcome some known obstructions

Stefan Haller, Tomasz Rybicki

It is proven that the identity component of the group preserving the leaves of a generalized foliation is perfect. This shows that a well-known simplicity theorem on the diffeomorphism group extends to the nontransitive case.

Viktor Ostrik

Let $U$ be the quantum group with divided powers in $l-$th root of unity and let $u\subset U$ be the Frobenius kernel. V.Ginzburg and S.Kumar proved that the cohomology algebra of $u$ with trivial coefficients is isomorphic to the functions algebra of the nilpotent cone of the corresponding Lie algebra. In this note we show that there exists tilting module $

Fedor Bogomolov, Yuri Tschinkel

Let $X$ be a K3 surface defined over a number field $K$. Assume that $X$ admits a structure of an elliptic fibration or an infinite group of automorphisms. Then there exists a finite extension $K&#39;/K$ such that the set of $K&#39;$-rational points is Zariski dense in $X$.

Michela Varagnolo, Eric Vasserot

We compute the convolution product on the equivariant K-groups of the cyclic quiver variety. We get a q-analogue of double-loop algebras, closely related to the toroidal quantum groups previously studied by the authors. We also give a geometric interpretation of the cyclic quiver variety in terms of equivariant torsion-free sheaves on the projective plane.

Valentin Vankov Iliev

Generalizations of Redfield&#39;s master theorem and superposition theorem are proved by using decomposition of the tensor product of several induced monomial representations of the symmetric group $S_d$ into transitive constituents. As direct consequences, one obtains several graphical corollaries. Given graphs $Γ_1,\hdots ,Γ_k$, with $d$ vertices, together

J. Du, H. Rui

Specht modules for an Ariki-Koike algebra have been investigated recently in the context of cellular algebras. Thus, these modules are defined as quotient modules of certain ``permutation&#39;&#39; modules, that is, defined as ``cell modules&#39;&#39; via cellular bases. We shall introduce in this paper Specht modules for an Ariki-Koike algebra as submodules

Jie Du, Hebing Rui

We investigated the representation thoery of an Ariki-Koike algebra whose Poincare polynomial associated with the &#34;bottom&#34;, i.e., the subgroup on which the symmetric group acts, is non-zero in the base field. We proved that the module category of such an Ariki-Koike algebra is Morita equivalent to the module category of a direct sum of tensor product

Marcin Daszkiewicz, Zbigniew Hasiewicz, Zbigniew Jaskolski

A free fermionic string quantum model is constructed directly in the light-cone variables in the range of dimensions $1<d<10$. It is shown that after the GSO projection this model is equivalent to the fermionic massive string and to the non-critical Rammond-Neveu-Schwarz string. The spin spectrum of the model is analysed. For $d=4$ the character generating f

Jean-Pierre Derendinger

A universal effective supergravity Lagrangian describing the thermal phases of heterotic strings on T^4 x S^1, IIA and IIB strings on K^3 x S^1 is constructed. The resulting non-perturbative phase structure is discussed.

I. Ya. Aref&#39;eva

The recent proposal by Polchinski and Susskind for the holographic flat space S-matrix is discussed. By using Feynman diagrams we argue that in principle all the information about the S-matrix in the interacting field theory in the bulk of the anti-de Sitter space is encoded into the data on the timelike boundary. The problem of locality of interpolating fie

B. Borasoy, B. R. Holstein

We examine the importance of resonances for the non-leptonic hyperon decays in the framework of chiral perturbation theory. Lower lying resonances are included into the effective theory. Integrating out the heavy degrees of freedom in the resonance saturation scheme generates higher order counterterms in the effective Lagrangian, providing an estimate of the

J. L Lucio, M. Napsuciale, M. D. Scadron, V. M. Villanueva

We evaluate the omega to rho pi transition and the omega to 3 pi decay using a Quark Level Linear Sigma Model ($QLσM$). We obtain $g^{QLσM}_{ωρπ}= (10.33 - 14.75) GeV^{-1}$ to be compared with other model dependent estimates averaging to $g_{ωρπ} = 16 GeV^{-1}$. We show that in the $QLσM$ a contact term is generated for the $ω\to 3 π$ decay. Although the con

L. Lavoura, Joao P. Silva

We analyze the prospects for observing CPT violation using neutral-meson P0-P0bar systems. Before one can claim a measurement of CPT violation, one must be able to rule out the possibility that its result is due to simpler new-physics effects. In particular, one must be able to separate the CPT-violating quantities from parameters violating the Delta P = ΔQ

Herbi Dreiner

This is the summary of a 90 minute introductory lecture on Supersymmetry presented at the Swiss Summer School on ``Hidden Symmetries and Higgs Phenomena&#39;&#39; at Zuoz, Engadin, in August 1998. I first review the hierarchy problem, and then discuss why we expect supersymmetry just around the corner, i.e. at or below $1\tev$. I focus on the specific exampl

M. Baldicchi, G. M. Prosperi

We briefly discuss the quark-antiquark Bethe-Salpeter equation and the quark Dyson-Schwinger equation derived in preceding papers. We also consider the q-qbar quadratic mass operator M^{2} = (w_{1} + w_{2})^{2} + U obtained by three-dimensional reduction of the BS equation and the related approximate center of mass Hamiltonian or linear mass operator H_{CM}

A. Gomez Nicola

We explore the extension of chiral perturbation theory out of thermal equilibrium. The pion decay constant becomes then a time-dependent function and we work within the Schwinger-Keldysh contour technique. A useful connection with curved space-time QFT allows to renormalise the model. We discuss the applicability of our approach within a relativistic heavy-i

A. P. Chapovsky, V. A. Khoze

We demonstrate that the results of the complete first order calculation of the non-factorizable QED corrections to the single-inclusive cross-sections for $e^+e^- \to W^+W^- \to 4$ fermions could be very well reproduced by a simple physically motivated ansatz. The latter allows to take into account effectively the screening role of the non-Coulomb radiative

D. Ferenc, U. Heinz, B. Tomasik, U. A. Wiedemann

Results on the pion phase-space density at freeze-out in sulphur-nucleus, Pb-Pb and pi-p collisions at the CERN SPS are presented. All heavy-ion reactions are consistent with the thermal Bose-Einstein distribution f=1/[exp(E/T)-1] at T ~ 120 MeV, modified for radial expansion. pi-p data are also consistent with f, but at T ~ 180 MeV and without radial flow.

G. P. Korchemsky, G. Sterman

We study power corrections to the differential thrust, heavy mass and related event shape distributions in $e^+e^-$-annihilation, whose values, $e$, are proportional to jet masses in the two-jet limit, $e\to 0$. The factorization properties of these differential distributions imply that they may be written as convolutions of nonperturbative &#34;shape&#34; f

R. J. Mountain, M. Artuso, R. Ayad, F. Azfar

The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented.

D. Asner

Based on a sample corresponding to 4.3 million produced tau-pair events, we have studied hadronic dynamics in the decay tau- --> nu_tau pi- pi0 pi0 in data recorded by the CLEO II detector operating at the CESR e+e- collider. The decay is dominated by the process tau --> nu_tau a_1(1260), with the a_1 meson decaying to three pions predominantly via the lowes

The OPAL Collaboration, G. Abbiendi et al

A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million events recorded with the OPAL detector at LEP. The fluctuations and correlations are analysed in terms of the normalized scaled factorial moments and cumulants up

Andris Ambainis

Inductive inference is a recursion-theoretic theory of learning, first developed by E. M. Gold (1967). This paper surveys developments in probabilistic inductive inference. We mainly focus on finite inference of recursive functions, since this simple paradigm has produced the most interesting (and most complex) results.

Nigel B. Wilding, Martin Schoen

Recent Monte Carlo simulation studies of a Lennard-Jones fluid confined to a mesoscopic slit-pore have reported evidence for ``critical depletion&#39;&#39; in the pore local number density near the liquid-vapour critical point. In this note we demonstrate that the observed depletion effect is in fact a simulation artifact arising from small systematic errors

S. Sorella, L. Capriotti

A recent technique, proposed to alleviate the ``sign problem disease&#39;&#39;, is discussed in details. As well known the ground state of a given Hamiltonian $H$ can be obtained by applying the imaginary time propagator $e^{-H τ}$ to a given trial state $ψ_T$ for large imaginary time $τ$ and sampling statistically the propagated state $ ψ_τ = e^{-H τ} ψ_T$.

A. V. Chechkin, V. Yu. Gonchar

We study simple approximations to fractional Gaussian noise and fractional Brownian motion. The approximations are based on spectral properties of the noise. They allow one to consider the noise as the result of fractional integration/differentiation of a white Gaussian noise. We study correlation properties of the approximation to fractional Gaussian noise

R. B. Stinchcombe, A. Misra, B K Chakrabarti

The divergences of both the length and time scales, at the magnetization- reversal transition in Ising model under a pulsed field, have been studied in the linearized limit of the mean field theory. Both length and time scales are shown to diverge at the transition point and it has been checked that the nature of the time scale divergence agrees well with th

J. M. Karimaki, E. V. Thuneberg

We discuss the general properties of periodic vortex arrangements in rotating superfluids. The different possible structures are classified according to the symmetry space-groups and the circulation number. We calculate numerically several types of vortex structures in superfluid 3He-A. The calculations are done in the Ginzburg-Landau region, but the method

Alexander N. Korotkov, Mikko A. Paalanen

A theoretical analysis of the charge sensitivity of the RF-SET is presented. We use the ``orthodox&#39;&#39; approach and consider the case when the carrier frequency is much less than $I/e$ where $I$ is the typical current through RF-SET. The optimized noise-limited sensitivity is determined by the temperature $T$, and at low $T$ it is only 1.4 times less t

Jun Kikuchi, Kiyoichiro Motoya, Touru Yamauchi, Yutaka Ueda

Nuclear magnetic resonance (NMR) of 31P and 51V nuclei has been measured in a spin-1/2 alternating-chain compound (VO)_2P_2O_7. By analyzing the temperature variation of the 31P NMR spectra, we have found that (VO)_2P_2O_7 has two independent spin components with different spin-gap energies. The spin gaps are determined from the temperature dependence of the

Y. Naveh, D. V. Averin

Current noise in superconductor-normal metal-superconductor (SNS) junctions is calculated within the scattering theory of multiple Andreev reflections (MAR). It is shown that the noise exhibits subharmonic gap singularities at $eV=2Δ/n$, $n=1,2,... $ both in single-mode junctions with arbitrary transparency $D$ and in multi-mode disordered junctions. The sub

B. Paredes, C. Tejedor, L. Brey, L. Martin-Moreno

We study the charged excitations of a double layer at filling factor 2 in the ferromagnetic regime. In a wide range of Zeeman and tunneling splittings we find that the low energy charged excitations are spin-isospin textures with the charge mostly located in one of the layers. As tunneling increases, the parent spin texture in one layer becomes larger and it

H. -M. Broeker, P. Grassberger

We study a plant population model introduced recently by J. Wallinga [OIKOS {\bf 74}, 377 (1995)]. It is similar to the contact process (`simple epidemic&#39;, `directed percolation&#39;), but instead of using an infection or recovery rate as control parameter, the population size is controlled directly and globally by removing excess plants. We show that th

Dipak Munshi, Peter Coles, Adrian L. Melott

We develop a diagrammatic technique to represent the multi-point cumulative probability density function (CPDF) of mass fluctuations in terms of the statistical properties of individual collapsed objects and relate this to other statistical descriptors such as cumulants, cumulant correlators and factorial moments. We use this approach to establish key scalin

S. W. Digel, E. Aprile, S. D. Hunter, R. Mukherjee

We present a study of the high-energy diffuse emission observed toward Orion by the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory. The total exposure by EGRET in this region has increased by more than a factor of two since a previous study. A simple model for the diffuse emission adequately fits the data; no significan

R. S. Roger, C. H. Costain, T. L. Landecker, C. M. Swerdlyk

We present maps of the 22MHz radio emission between declinations -28d and +80d, covering ~73% of the sky, derived from observations with the 22MHz radiotelescope at the Dominion Radio Astrophysical Observatory (DRAO). The resolution of the telescopt (EWxNS) is 1.1d x 1.7d secant(zenith angle). The maps show the large scale features of the emission from the G

P. Jablonka, T. J. Bridges, A. Sarajedini, G. Meylan

We present observations with the Hubble Space Telescope Wide Field Planetary Camera 2 of three fields centered on super-metal-rich globular clusters in the bulge of M31. Our (I,V-I) color-magnitude diagrams reach as faint as I ~ 26.5 mag and clearly reveal the magnitude of the first ascent red giant branch (RGB) tip. We find that the apparent I magnitude of

L. Tresse

Galaxy redshift surveys are outstanding tools for observational cosmology. Mapping the universe as outlined by galaxies leads to fundamental measurements which refine our knowledge of its structure and evolution. Redshift acquisition has undergone tremendous progress thanks to advances in technology, and redshift surveys appear nowadays as routine. Even thou

K. Wilke, C. Moellenhoff, M. Matthias

For the intermediate-type barred galaxy NGC2336 stationary models are constructed which reproduce in a consistent manner the observed distribution of the luminous matter and the observed gas kinematics in those regions affected by the bar. We present 2D fits to the observed NIR-band luminosity distribution that consist of three components: a bulge, a bar, an

F. Nasseri, A. Nayeri

A brief report on the first IPM School on Cosmology 1999 is given. The School on &#34;Large Scale Structure Formation&#34; was held for the first time in Kish University, Kish Island, Iran. The next IPM School on Cosmology will be held in 2002 on &#34;High z-Universe&#34; and &#34;CMBR&#34;.

Ian R. Stevens, Duncan A. Forbes, Ray P. Norris

We present a multiwavelength analysis of the prominent active galaxy NGC1365, in particular looking at the radio and X-ray properties of the central regions of the galaxy. We analyse ROSAT observations of NGC1365, and discuss recent ASCA results. In addition to a number of point sources in the vicinity of NGC1365, we find a region of X-ray emission extending

Roland Svensson

A summary is given of the high-lights during the Reykjavik Midsummer Symposium on Non-Linear Phenomena in Accretion Discs around Black Holes. Such high-lights include the recent advances on understanding: 1) the accretion disc solution branch dominated by advection (i.e., advection dominated accretion flows, ADAFs), 2) the importance of magnetic fields in ma

Roland Svensson

There is strong observational evidence that a quasi-thermal population of electrons (or pairs) exists in compact X-ray sources. It is, however, unclear what mechanism thermalizes the particles. Here, two processes, Coulomb scattering and synchrotron self-absorption, that may be responsible for the thermalization, are reviewed. The parameter spaces in which r

Boris Stern

Despite that gamma-ray bursts is a phenomenon quite different from accreting compact objects, it could be that their hard X-ray emission is associated with a very similar mechanism of energy dissipation. In both cases, we could deal with reconnection of a turbulent magnetic field with intensive e+e- pair production and quasi-thermal Comptonization.

D. S. Wiebe, B. M. Shustov, A. V. Tutukov

Elliptical galaxies are often assumed to be the primary source of heavy elements in the intracluster medium (ICM), with the contribution of other morphological types being negligible. In this paper we argue that a role of spiral galaxies in the chemical evolution of the ICM is also important. This statement rests upon our recent calculations of the heavy ele

P. O. Fedichev, G. V. Shlyapnikov

We discuss dissipative dynamics of a vortex state in a trapped Bose-condensed gas at finite temperature and draw a scenario of decay of this state in a static trap. The interaction of the vortex with the thermal cloud transfers energy from the vortex to the cloud and induces the motion of the vortex core to the border of the condensate. Once the vortex reach

W. Bietenholz, I. Hip

We construct a number of lattice fermions, which fulfill the Ginsparg-Wilson relation either exactly or approximately, and test them in the framework of the 2-flavor Schwinger model. We start from explicit approximations within a short range, and study this formulation, as well as its correction to an exact Ginsparg-Wilson fermion by the ``overlap formula&#3

K. Kaviani, A. M. Ghezelbash

By using the approach of non-commutative geometry, we study spinors and scalars on the two layers AdS$_{d+1}$ space. We have found that in the boundary of two layers AdS$_{d+1}$ space, by using the AdS/CFT correspondence, we have a logarithmic conformal field theory. This observation propose a way to get the quantum field theory in the context of non-commuta

R. Krasnopolsky, Z. -Y. Li, R. D. Blandford

The magneto-centrifugal model for jet formation is studied by time-dependent simulations reaching steady state in a cold gas with negligible fluid pressure, in an axisymmetric geometry, using a modification of the Zeus3D code adapted to parallel computers. The number of boundary conditions imposed at the coronal base takes into account the existence of the f

S. Wakimoto, R. J. Birgeneau, Y. Endoh, P. M. Gehring

Neutron-scattering experiments have been performed on lightly-doped La(2-x)Sr(x)CuO4 single crystals in both the insulating (x=0.03,0.04,0.05) and superconducting (x=0.06) regions. Elastic magnetic peaks are observed at low temperatures in all samples with the maximum peak linewidth occuring at the critical concentration x_c=0.05. New incommensurate peaks ar

Andris Ambainis

We show that any quantum algorithm searching an ordered list of n elements needs to examine at least 1/12 log n-O(1) of them. Classically, log n queries are both necessary and sufficient. This shows that quantum algorithms can achieve only a constant speedup for this problem. Our result improves lower bounds of Buhrman and de Wolf(quant-ph/9811046) and Farhi

E. Prodan

We extend the method discovered by A Y Alekseev et al to the case of fermions in external fields. A general formula for conductance G is proved. In the (1+1)-D case with symmetry at time reflection, it is shown that: G=e^2/h+o(a^), where a is the strength of the external field. In (3+1)-D free case, it is checked that G=n*e^2/h, where n is the number of the

Gunn Quznetsov

The Clifford pentads of the 4X4 complex matrices define the current vectors of the particles. The weak isospin transformation divides the particles on two components, which scatter in the 2-dimensional antidiagonal Clifford matrices space. A physics objects move in the 3-dimensional diagonal Clifford matrices space. This sectioning of the 5-dimensional space

Willi Jager, Yoshimi Saito

Let H = -(1/m(x))L be the reduced wave operator defined on the N-dimensional Euclidean space, where \f L is the Laplacian. Here m(x) is a positive step function with possible countably infinte surfaces of discontinuity (separating surfaces) under the compatibilty condition (1.12) on each separating surface. These compatibily condition allows us to treat the

Willi Jager, Yoshimi Saito

Consider the differential operator H = -(1/m(x))L, where L is the N-dimensional Laplacian, in the weighted Hilbert space of square integrable functions on N-dimensional Euclidean space with weight m(x)dx. Here m(x) is a positive step function with a surface S of discontinuity (the separation surface). So far the stratified media in which the separating surfa

Chris Pladdy, Yoshimi Saito, Tomio Umeda

We shall investigate the asymptotic behavior of the extended resolvent R(s) of the Dirac operator as |s| increases to infinity, where s is a real parameter. It will be shown that the norm of R(s), as a bounded operator between two weighted Hilbert spaces of square integrable functions on the 3-dimensional Euclidean space, stays bounded. Also we shall show th

Laurent Querella

This dissertation investigates three main topics, all of which dealing with alternative, higher-order gravity theories in four dimensions. Firstly, we study the variational and conformal structure of those theories. Next, we analyse their Hamiltonian formulation and in particular its relationship with the famous ADM canonical version of general relativity. F

Reza Mansouri, Forough Nasseri

Assuming the space dimension is not constant, but varies with the expansion of the Universe, a Lagrangian formulation for a toy model Universe is given. There is a free paremeter in the theory, $C$, with which we can fix the dimension of space at the Planck time. The standard FRW model corresponds to the limiting case $C \to +\infty$. We study the Wheeler-De

A. Alan Middleton

The low-temperature driven or thermally activated motion of several condensed matter systems is often modeled by the dynamics of interfaces (co-dimension-1 elastic manifolds) subject to a random potential. Two characteristic quantitative features of the energy landscape of such a many-degree-of-freedom system are the ground-state energy and the magnitude of

George F. Smoot

Synchrotron emission is an important process in Galactic dynamics and a potentially confusing foreground for cosmic microwave background (CMB) radiation observations. Though the mechanism of synchrotron emission is well understood, the details for the Galaxy and many external sources are not well characterized. Quality maps at multiple frequencies are lackin

M. E. Putman, B. K Gibson

With the onset of the HI Parkes All-Sky Survey, a new view of the high-velocity cloud (HVC) distribution in the southern sky is being revealed. The dense spatial sampling and unbiased coverage of HIPASS gives it multiple advantages over previous surveys of the southern sky. Detailed views of the clouds&#39; structure and large mosaics of the HI sky allow us

Michael R. Meyer, Fred C. Adams, Lynne A. Hillenbrand, John M. Carpenter

We summarize recent observational and theoretical progress aimed at understanding the origin of the stellar initial mass function (IMF) with specific focus on galactic star-forming regions. We synthesize data from various efforts to determine the IMF in very young, partially-embedded stellar clusters and find: i) no significant variations in the low-mass IMF

Michael W. Deem

This comment points out that simulation results of Mehrabi and Sahimi [Phys. Rev. Lett. 82, 735 (1999)] are iconsistent with exact bounds, renormalization group calculations, and previous numerical simulations.

Konstantin Kladko

Einstein-Podolsky-Rosen (EPR) paradox is considered in a relation to a measurement of an arbitrary quantum system . It is shown that the EPR paradox always appears in a gedanken experiment with two successively joined measuring devices.

Ruggero Maria Santilli

After reviewing the basic role of Lie&#39;s theory for the mathematics and physics of this century, we identify its limitations for the treatment of systems beyond the local-differential, Hamiltonian and canonical-unitary conditions of the original conception. We therefore outline three sequential generalized mathematics introduced by the author under the na

Philip Gibbs

A famous problem posed by Diophantus was to find sets of distinct positive rational numbers such that the product of any two is one less than a rational square. Some sets of six such numbers are presented and the computational algorithm used to find them is described. A classification of quadruples and quintuples with examples and statistics is also given.

Jean-Francois Burnol

I give a new derivation of the Explicit Formula for an arbitrary number field and abelian Dirichlet-Hecke character, which treats all primes in exactly the same way, whether they are discrete or archimedean, and also ramified or not. This is followed with a local study of a Hilbert space operator, the ``conductor operator&#39;&#39;, which is expressed as H =

Joel David Hamkins

The Wholeness Axioms, proposed by Paul Corazza, axiomatize the existence of an elementary embedding j:V-->V. Formalized by augmenting the usual language of set theory with an additional unary function symbol j to represent the embedding, they avoid the Kunen inconsistency by restricting the base theory ZFC to the usual language of set theory. Thus, under the

E. Torrente-Lujan

We present a short review of the present status of the problem of neutrino masses and mixing including a survey of theoretical motivations and models, experimental searches and implications of recently appeared solar and atmospheric neutrino data, which strongly indicate nonzero neutrino masses. Such data apparently requires the existence of light sterile ne

Li-Kun Hao, Feng Yuan, Kuang-Ta Chao

We present a calculation for the photoproduction of $η_c$ under the framework of NRQCD factorization formalism. We find a quite unique feature that the color-singlet contribution to this process vanishes at not only the leading order but also the next to leading order perturbative QCD calculations and that the dominant contribution comes from the color-octet

C. Spieles, R. Vogt, L. Gerland, S. A. Bass

Charmonium production and absorption in heavy ion collisions is studied with the Ultrarelativisitic Quantum Molecular Dynamics model. We compare the scenario of universal and time independent color-octet dissociation cross sections with one of distinct color-singlet J/psi, psi&#39; and chi_c states, evolving from small, color transparent configurations to th

C. Adloff

The elastic electroproduction of rho mesons is studied at HERA with the H1 detector for a photon virtuality in the range 1 < Q^2 < 60 GeV^2 and for a hadronic centre of mass energy in the range 30 < W < 140 GeV. The shape of the pipi mass distribution in the rho resonance region is measured as a function of Q^2. The full set of rho spin density matrix elemen

Ivan G. Avramidi, Giampiero Esposito

Boundary conditions play a crucial role in the path-integral approach to quantum gravity and quantum cosmology, as well as in the current attempts to understand the one-loop semiclassical properties of quantum field theories. Within this framework, one is led to consider boundary conditions completely invariant under infinitesimal diffeomorphisms on metric p

Hong-Gang Luo, Zu-Jian Ying, Shun-Jin Wang

Based on an equation of motion approach the single impurity Anderson model(SIAM) is reexamined. Using the cluster expansions the equations of motion of Green functions are transformed into the corresponding equations of motion of connected Green functions, which provides a natural and uniform truncation scheme. A factor of two missing in the Lacroix&#39;s ap

Eduardo Aponte, Ernesto Medina

We study sums of directed paths on a hierarchical lattice where each bond has either a positive or negative sign with a probability $p$. Such path sums $J$ have been used to model interference effects by hopping electrons in the strongly localized regime. The advantage of hierarchical lattices is that they include path crossings, ignored by mean field approa

Amit Kr. Chattopadhyay

The effects of spatially correlated noise on a phenomenological equation equivalent to a non-local version of the Kardar-Parisi-Zhang equation are studied via the dynamic renormalization group (DRG) techniques. The correlated noise coupled with the long ranged nature of interactions prove the existence of different phases in different regimes, giving rise to

Nilakshi, R. K. S. Yadav, V. Mohan, A. K. Pandey

The CCD magnitudes in Johnson $BV$ and Cousins $RI$ photometric passbands are determined for 18 stars in the field of GRB 990123. These measurements can be used in carrying out precise CCD photometry of the optical transient of GRB 990123 using differential photometric techniques during non--photometric sky conditions. A comparison with previous photometry i

Dongsu Bak, Soo-Jong Rey

We study dynamical aspects of holographic correspondence between d=5 anti-de Sitter supergravity and $d=4$ super Yang-Mills theory. We probe causality and locality of ambient spacetime from super Yang-Mills theory by studying transmission of low-energy brane waves via an open string stretched between two D3-branes in Coulomb branch. By analyzing two relevant

Marco Billo, Sergio Cacciatori, Frederik Denef, Pietro Fre

We begin by presenting the superparticle action in the background of N=2, D=4 supergravity coupled to n vector multiplets interacting via an arbitrary special Kahler geometry. Our construction is based on implementing kappa-supersymmetry. In particular, our result can be interpreted as the source term for N=2 BPS black holes with a finite horizon area. When

K. J. Juge, J. Kuti, C. J. Morningstar

Hybrid b-bar-gb molecules in which the heavy b-bar-b pair is bound together by the excited gluon field g are studied using the Born-Oppenheimer expansion and numerical simulations. The consistency of results from the two approaches reveals a simple and compelling physical picture for heavy hybrid states.

Nathan Berkovits

The superstring is quantized in a manner which manifestly preserves a U(5) subgroup of the (Wick-rotated) ten-dimensional super-Poincaré invariance. This description of the superstring contains critical N=2 worldsheet superconformal invariance and is a natural covariantization of the U(4)-invariant light-cone Green-Schwarz description.

A. A. Tseytlin, K. Zarembo

We study some aspects of short-distance interaction between parallel D3-branes in type 0 string theory as described by the corresponding world-volume gauge theory. We compute the one-loop effective potential in the non-supersymmetric SU(N) x SU(N) gauge theory (which is a Z_2 projection of the U(2N) n=4 SYM theory) representing dyonic branes composed of N el

N. Berkovits, C. Vafa, E. Witten

We review a formalism of superstring quantization with manifest six-dimensional spacetime supersymmetry, and apply it to AdS_3 x S^3 backgrounds with Ramond-Ramond flux. The resulting description is a conformal field theory based on a sigma model whose target space is a certain supergroup SU&#39;(2|2).

E. Scapparone

We present first results about the measurement of the charged hadrons production by atmopsheric muons in the rock above MACRO. A comparison between the measurerate with the Monte Carlo expectation is presented.

G. G. Williams, H. S. Park, E. Ables, D. L. Band

We report on the very early time search for an optical afterglow from GRB 971227 with the Livermore Optical Transient Imaging System (LOTIS). LOTIS began imaging the `Original&#39; BATSE error box of GRB 971227 approximately 14 s after the onset of gamma-ray emission. Continuous monitoring of the position throughout the evening yielded a total of 499 images

N. O. Agasian, B. O. Kerbikov, V. I. Shevchenko

We discuss the possibility of existence of colour superconducting state in real QCD vacuum with nonzero gluon condensate. We argue, that nonperturbative gluonic fields might play a crucial role in colour superconductivity scenario.

J. E. Han, O. Gunnarsson, V. Eyert

We present a calculation of the Hg phonon self-energy for a model of A3C60 (A= K, Rb). The orientational disorder of the C60 molecules is included, and the lowest order self-energy diagram is considered. The calculations illustrate that due to the violation of momentum conservation by the orientational disorder, Raman scattering can measure the decay of a ph

B. Adeva, F. Gomez, A. Pazos, R. Pfau

We present the performance of a new proportional gas detector. Its geometry consists of a cathode plane with 70x70 micron apertures, crossed by 25 micron anode strips to which it is attached by 50 micron kapton spacers. In the region where the avalanche takes place, the anode strips are suspended in the gas mixture like in a standard wire chamber. This detec

S. Jhingan, G. Magli

Non-static, spherically symmetric clusters of counter-rotating particles, of the type first introduced by Einstein, are analysed here. The initial data space can be parameterized in terms of three arbitrary functions, namely; initial density, velocity and angular momentum profiles. The final state of collapse, black hole or naked singularity, turns out to de

E. Scapparone

We present first results about the measurement of the charged hadrons production by atmopsheric muons in the rock above MACRO. A comparison between the measure rate with the Monte Carlo expectation is presented

Karol Zyczkowski

The problem of of how many entangled or, respectively, separable states there are in the set of all quantum states is investigated. We study to what extent the choice of a measure in the space of density matrices describing N--dimensional quantum systems affects the results obtained. We demonstrate that the link between the purity of the mixed states and the

R. Caracciolo, F. Gliozzi, R. Tateo

We construct a topological invariant of the renormalization group trajectories of a large class of 2D quantum integrable models, described by the thermodynamic Bethe ansatz approach. A geometrical description of this invariant in terms of triangulations of three-dimensional manifolds is proposed and associated dilogarithm identities are proven.

A. Celani, A. Lanotte, A. Mazzino

A compressible generalization of the Kraichnan model (Phys. Rev. Lett. 72, 1016 (1994)) of passive scalar advection is considered. The dynamical role of compressibility on the intermittency of the scalar statistics is investigated for the direct cascade regime. Simple physical arguments suggest that an enhanced intermittency should appear for increasing comp