December 1998 arXiv papers — page 21

Joel Smoller, Blake Temple

We construct the simplest solution of the Einstein equations that incorporates a shock-wave into a standard Friedmann-Robertson-Walker metric whose equation of state accounts for the Hubble constant and the microwave background radiation temperature. This produces a new solution of the Einstein equations from which we are able to derive estimates for the sho

L. G. Althaus, O. G. Benvenuto

In this study we compute the structure and evolution of carbon-oxygen DA white dwarfs by means of a detailed and updated evolutionary code. We treat the energy transport by convection within the formalism of the full spectrum turbulence theory, as given by the Canuto, Goldman and Mazzitelli (CGM) model. We explore the effect of various hydrogen layer masses

James Liebert

Astrophysical objects below the stellar mass limit but well above the mass of Jupiter eluded discovery for nearly three decades after Kumar first proposed their existence, and for two decades after Tarter proposed the name "brown dwarfs." The first unambiguous discoveries of planetary (51 Peg B) and brown dwarf (Gliese 229B) companions occurred about

Reuven Ramaty, Richard Lingenfelter

Three different models have been proposed for LiBeB production by cosmic rays: the CRI model in which the cosmic rays are accelerated out of an ISM of solar composition scaled with metallicity; the CRS model in which cosmic rays with composition similar to that of the current epoch cosmic rays are accelerated out of fresh supernova ejecta; and the LECR model

C. L. Fryer, W. Benz, M. Herant, S. A. Colgate

The accretion induced collapse (AIC) of a white dwarf into a neutron star has been invoked to explain gamma-ray bursts, Type Ia supernovae, and a number of problematic neutron star populations and specific binary systems. The ejecta from this collapse has also been claimed as a source of r-process nucleosynthesis. So far, most AIC studies have focussed on de

Joseph Silk, Rychard J. Bouwens

Bulges, often identified with the spheroidal component of a galaxy, have a complex pedigree. Massive bulges are generally red and old, but lower mass bulges have broader dispersions in color that may be correlated with disk colors. This suggests different formation scenarios. I will review possible formation sequences for bulges, describe the various signatu

M. A. Perez-Torres, J. M. Marcaide, J. C. Guirado, E. Ros

We observed the pair of radio sources 1150+812 and 1803+784 in November 1993 with a VLBI array, simultaneously recording at 8.4 and 2.3 GHz. We determined the angular separation between the two sources with submilliarcsecond accuracy by using differential techniques. This result demonstrates the feasibility of high precision differential astrometry for radio

J. Greiner, G. H. Tovmassian, R. DiStefano, A. Prestwich

We have observed V751 Cyg with the ROSAT HRI during its recent optical low state and clearly detect it at a count rate of 0.015 cts/s. The X-ray intensity is a factor of ~20 higher than the upper limit obtained with the ROSAT PSPC during the optical high state. Spectral investigations suggest a very soft X-ray spectrum. We investigate archival IUE data of V7

K. Hurley

We discuss the utilization of INTEGRAL as a gamma-ray burst detector in the interplanetary network. IBIS will have an inherent GRB detection and localization capability. However, the SPI anticoincidence shield will also be a sensitive burst detector which, in conjunction with other spacecraft, will make it possible to localize three to four times more bursts

K. Hurley

To anyone who has read a scientific journal or even a newspaper in the last six months, it might appear that cosmic gamma-ray bursts hold no more mysteries: they are cosmological, and possibly the most powerful explosions in the Universe. In fact, however, bursts remain mysterious in many ways. There is no general agreement upon the nature of the event which

C. A. Haswell, R. I. Hynes

Results from an HST/multiwavelength campaign on the 1996 outburst of GRO J1655-40 are reported. We find evidence for an approximately isothermal outer disk in GRO J1655-40 during the decline from outburst, possibly indicating the outer disk being maintained in the hot state. HST observations of GRO J0422+32 made 2 years after outburst reveal a sharply peaked

T. P. Krichbaum, A. Witzel, J. A. Zensus

We summarize previous VLBI observations of Sgr A* at millimeter wavelengths and present new results from VLBI observations at 86 and at 215 GHz. At 86 GHz the measured closure phase is close to zero, consistent with a point-like or symmetric structure of 190 +/- 30 micro-arcsec size. At 215 GHz we have detected Sgr A* with a signal-to-noise ratio of 6. This

Amiel Sternberg, David A. Neufeld

We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states, and the H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV-pumping of fluorescent H2 emissi

B. Fuchs

Decompositions of the rotation curves of NGC2613, 3198, 6505, and 7184 are analysed. For these galaxies the radial velocity dispersions of the stars have been measured and their morphology is clearly discernible. If the parameters of the decompositions are chosen according to the `maximum' disk hypothesis, the Toomre Q stability parameter is systematical

A. Moneti, J. A. D. L. Blommaert, F. Najarro, D. F. Figer

We present initial results of a spectroscopic study of the Pistol and of the cocoon stars in the Quintuplet Cluster. From ISOCAM CVF 5--17 micron spectroscopy of the field of the Pistol Star, we have discovered a nearly spherical shell of hot dust surrounding this star, a probable LBV. This shell is most prominent at lambda > 12 micron, and its morphology cl

Olivier Perdereau

EROS-II is a second generation microlensing experiment. The experimental setup, in operation at the European Southern Observatory (ESO) at La Silla (Chile) since mid-1996 is briefly described together with its scientific objectives. The first results from our microlensing searches towards the Small Magellanic Cloud (SMC) and the Galactic Plane are presented.

S. Darbon, A. Zavagno, C. Savine, V. Ducci

We present visible and near IR images of the compact HII region Sh 152. Some of these images reveal the presence of Extended Red Emission (ERE) around 698 nm and emission from Unidentified Infra Red Bands (UIRBs) at 3.3 and 6.2 micron. Other images show the near infrared (7-12 micron) continuous emission of the nebula. The ERE emission is found to coincide w

Kirk Korista

I present a brief review about our ideas concerning the origin and nature of the broad line emitting gas. This is one of the outstanding problems in quasar research. I suggest the establishment of a central data base of high quality quasar spectra as a means to realize an understanding of quasars.

Bruno Leibundgut, Gertrud Contardo, Patrick Woudt, Jason Spyromilio

A new component of the Universe which leads to an accelerated cosmic expansion is found from the measurements of distances to high-redshift type Ia supernovae. We describe the method and the results obtained from the observations of distant supernovae. The dependence on the understanding of the local type Ia supernovae is stressed. The lack of a good underst

Kirk Korista

After a short review of the quasar problem and what we can hope to learn from their emission line spectra, I discuss the current body of knowledge concerning quasar emission lines and their relationships to the local and ionizing continua. I propose a hypothesis that the Baldwin effect is due to a characteristic relationship between the continuum spectral en

Raul Jimenez, David V. Bowen, Francesca Matteucci

We use a model of galaxy disk formation to explore the metallicities, dust content, and neutral-gas mass density of damped Lyman-$α$ (D\lya) absorbers. We find that the [Zn/H] abundance measurements of D\lya systems now available can be reproduced either by a population of low surface brightness (LSB) galaxies forming at redshifts $z > 3$, whose chemical con

J. L. Puget, G. Lagache, D. L Clements, W. T. Reach

FIRBACK is a deep survey conducted with the ISOPHOT instrument aboard the Infrared Space Observatory (ISO) at an effective wavelength of 175 $μ$m. We present here results we have obtained on the first field, the so-called Marano1 which covers around 0.25 square degree. We find that the source density for objects with a flux above 200 mJy exceeds the counts e

F. -J. Zickgraf

The class of B[e] supergiants is characterized by a two-component stellar wind consisting of a normal hot star wind in the polar zone and a slow and dense disk-like wind in the equatorial region. The properties of the disk wind are discussed using satellite UV spectra of stars seen edge-on, i.e. through the equatorial disk. These observations show that the d

V. F. Cardone, R. de Ritis, A. A. Marino

We present in this paper a simple method to obtain informations on galaxy models parameters using the measured value of the microlensing optical depth. Assuming a 100 percent MACHO's dark halo, we ask the predicted optical depth for a given model to be the same as the observed one, in a given direction. Writing the optical depth in terms of the given hal

Ilaria Cagnoni, Antonella Fruscione, Iossif E. Papadakis

We present spectral and timing analysis of all the data collected by the Extreme Ultraviolet Explorer for the BL Lac object Mrk 421 from 1994 to 1997. During these years Mrk 421 has been observed by EUVE 4 times with the DS/Spectrograph and 2 times with the imaging telescopes for a total of ~1.4 millions seconds. The total EUVE light curve seems to be smooth

Jay A. Frogel

Observations of the stellar content of the bulge of the Milky Way can provide critical guidelines for the interpretation of observations of distant galaxies, in particular for understanding their stellar content and evolution. In this brief overview I will first highlight some recent work directed towards measuring the history of star formation and the chemi

Michael D. Gregg, Michael J. West

Although the existence of a faint background of starlight in the core of the Coma cluster has been well established (1,2), its origin is uncertain. This vast sea of stars could have formed outside the galaxies, using gas left over from the time of the cluster's birth. Alternatively, it might be the accumulated debris generated by interactions between the

Una Hwang, Richard F. Mushotzky, Jack O. Burns, Yasushi Fukazawa

We present ASCA X-ray observations of a sample of five groups selected from a cross-correlation of the ROSAT All-Sky Survey with the White et al. optical catalog of groups. These X-ray bright groups significantly increase the number of known systems with temperatures between 2 and 3 keV. They have element abundances of roughly 0.3 times solar that are typica

Sandip K. Chakrabarti

Outflows are common in many astrophysical systems which contain black holes and neutron stars. Difference between stellar outflows and outflows from these systems is that the outflows in these systems have to form out of the inflowing material only. The inflowing material can form a hot and dense cloud surrounding the compact object either because of centrif

M. E. J. Newman, Gunther J. Eble

Recent Fourier analyses of fossil extinction data have indicated that the power spectrum of extinction during the Phanerozoic may take the form of 1/f noise, a result which, it has been suggested, could be indicative of the presence of "critical dynamics" in the processes giving rise to extinction. In this paper we examine extinction power spectra in

G. K. Fanourakis, D. Fassouliotis, A. Leisos, N. Mastroyiannopoulos

This paper describes two generalization schemes of the Optimal Variables technique in estimating simultaneously two Trilinear Gauge Couplings. The first is an iterative procedure to perform a 2-dimensional fit using the linear terms of the expansion of the probability density function with respect to the corresponding couplings, whilst the second is a cluste

Michael Gutperle, Vipul Periwal

Sen has shown that tachyon condensation in Dbrane-anti-Dbrane configurations can lead to remarkable connections between string theories. A consequence of his results is that there is a minimal value of the radial coordinate $r_{c} \propto \sqrt{α'} (gN)^{1/(9-p)}$ such that N units of D$p$brane charge cannot be localized to values smaller than $r_{c}.$ A

S. Carlip

Restricted to a black hole horizon, the ``gauge'' algebra of surface deformations in general relativity contains a Virasoro subalgebra with a calculable central charge. The fields in any quantum theory of gravity must transform accordingly, i.e., they must admit a conformal field theory description. Applying Cardy's formula for the asymptotic den

A. C. Doherty, K. Jacobs

We present a formulation of feedback in quantum systems in which the best estimates of the dynamical variables are obtained continuously from the measurement record, and fed back to control the system. We apply this method to the problem of cooling and confining a single quantum degree of freedom, and compare it to current schemes in which the measurement si

Edward Witten

In ${\cal N}=4$ super Yang-Mills theory on a four-manifold $M$, one can specify a discrete magnetic flux valued in $H^2(M,\Z_N)$. This flux is encoded in the AdS/CFT correspondence in terms of a five-dimensional topological field theory with Chern-Simons action. A similar topological field theory in seven dimensions governs the space of ``conformal blocks&#3

M. E. Mora-Ramos, F. J. Rodriguez, L. Quiroga

Polaron binding energy and effective mass are calculated for semiconductors with wurtzite crystalline structure from the first order electron-phonon corrections to the self-energy. A recently introduced Frohlich-like electron-phonon interaction Hamiltonian which accounts for the LO and TO polarizations mixing due to the anisotropy is used in the calculation.

Mladen Bestvina

Artin groups of finite type are not as well understood as braid groups. This is due to the additional geometric properties of braid groups coming from their close connection to mapping class groups. For each Artin group of finite type, we construct a space (simplicial complex) analogous to Teichmueller space that satisfies a weak nonpositive curvature condit

Biswajoy Brahmachari

If the smallness of the mass of the sterile neutrino is to be explained by the see-saw mechanism, the off-diagonal entries of the mass matrix needs to be protected by some symmetry not far above the electroweak scale. We implement see-saw mechanism in a gauge model based on $SU(2)^q_L \times SU(2)^l_L \times U(1)^q_Y \times U(1)^l_Y$ un-unified gauge group w

Martin Bucher, David N. Spergel

A smooth unclustered dark matter component with negative presure could reconcile a flat universe with the many observations that find a density in ordinary, clustered matter well below the critical density and also explain the recent high redshift supernova data suggesting that the expansion of the universe is now accelerating. For a perfect fluid negative p

N. Morozov, L. N. Bulaevskii, M. P. Maley, J. Y. Coulter

We measured the angular dependence of the c-axis magnetoresistance rho_c(B) of Bi-2212 irradiated with heavy ions. At temperatures near 68 K the scaling of rho_c(B) with the c-axis magnetic field component B_perp is broken and the in-plane field, B_parallel, affects rho_c. At this temperature, at a specific field B_cr \approx B_Phi/2, magnetoresistance becom

Anders Irbäck, Erik Sandelin

We study the phase behavior of single homopolymers in a simple hydrophobic/hydrophilic off-lattice model with sequence independent local interactions. The specific heat is, not unexpectedly, found to exhibit a pronounced peak well below the collapse temperature, signalling a possible low-temperature phase transition. The system size dependence at this maximu

Stephen H. Geer, Dallas C. Kennedy

Measurements of the cosmic ray pbar/p ratio are compared to predictions from an inhomogeneous disk-diffusion model of pbar production and propagation within the Galaxy, combined with a calculation of the modulation of the interstellar cosmic ray spectra as the particles propagate through the heliosphere to the Earth. The predictions agree with the observed p

Nima Arkani-Hamed, Martin Schmaltz

Dvali and Shifman have proposed a field-theoretic mechanism for localizing gauge fields to "branes" in higher dimensional spaces using confinement in a bulk gauge theory. The resulting objects have a number of qualitative features in common with string theory D-branes; they support a gauge field and flux strings can end on them. In this letter, we ex

A. De Martino, M. Moriconi

We study the scattering theory for the Gross-Neveu model on the half-line. We find the reflection matrices for the elementary fermions, and by fusion we compute the ones for the two-particle bound-states, showing that they satisfy non-trivial bootstrap consistency conditions. We also compute more general reflection matrices for the Gross-Neveu model and the

M. Arnsdorf, R. S. Garcia

We demonstrate the existence of spinorial states in a theory of canonical quantum gravity without matter. This should be regarded as evidence towards the conjecture that bound states with particle properties appear in association with spatial regions of non-trivial topology. In asymptotically trivial general relativity the momentum constraint generates only

Vasily Golyshev, Valery Lunts, Dmitri Orlov

We work out the notion of mirror symmetry for abelian varieties and study its properties. Our construction are based on the correspondence between two $Q$--algebraic groups. One is the Hodge (or special Mumford--Tate) group. The second group $\bar{Spin(A)}$ is defined as follows: the group of autoequivalences of the bounded derived category of coherent sheav

N. Hambli

The IKKT matrix model was proposed to be a non-perturbative formulation of type IIB superstring theory. One of its important consistency criteria is that the leading one-loop $1/r^8$ effective interaction between a cluster of type IIB D-objects should not receive any corrections from higher loop effects for it to describe accurately the type IIB supergravity

Ulf H. Danielsson, Esko Keski-Vakkuri, Martin Kruczenski

In this paper we investigate the relation between the bulk and boundary in AdS/CFT. We first discuss the relation between the Poincare and the global vacua, and then study various probes of the bulk from the boundary theory point of view. We derive expressions for retarded propagators and note that objects in free fall look like expanding bubbles in the boun

S. M. Ivashkovich, V. V. Shevchishin

We study the envelopes of meromorphy of neighborhoods of symplectically immersed two-spheres in complex Kähler surfaces using the Gromov's theory of pseudoholomorphic curves. The construction of a complete family of holomorphic deformations of a non-compact complex curve in a complex manifold, parametrized by a finite codimension analytic subset of a Ban

Antonaldo Diaferio, Guinevere Kauffmann, Joerg M. Colberg, Simon D. M. White

This is the third paper in a series which combines N-body simulations and semi-analytic modelling to provide a fully spatially resolved simulation of the galaxy formation and clustering processes. Here we extract mock redshift surveys from our simulations: a Cold Dark Matter model with either Omega_0=1 (tauCDM) or Omega_0=0.3 and Lambda=0.7 (LambdaCDM). We c

H. Feldmann, R. Oppermann

We analyse the competition between spin glass (SG) order and local pairing superconductivity (SC) in the fermionic Ising spin glass with frustrated fermionic spin interaction and nonrandom attractive interaction. The phase diagram is presented for all temperatures T and chemical potentials μ. SC-SG transitions are derived for the relevant ratios between attr

Juan Antonio Valiente Kroon

A discussion of how to calculate asymptotic expansions for polyhomogeneous spacetimes using the Newman-Penrose formalism is made. The existence of logarithmic Newman-Penrose constants for a general polyhomogeneous spacetime (i.e. a polyhomogeneous spacetime such that $Ψ_0=Ø(r^{-3}\ln ^{N_3})$) is addressed. It is found that these constants exist for the gene

S. M. Klishevich

We study the propagation of gauge fields with arbitrary integer spins in the symmetrical Einstein space of any dimensionality. We reduce the problem of obtaining a gauge-invariant Lagrangian of integer spin fields in such background to an purely algebraic problem of finding a set of operators with certain features using the representation of high-spin fields

J. Froehlich, P. A. Marchetti

We propose explicit recipes to construct the euclidean Green functions of gauge-invariant charged, monopole and dyon fields in four-dimensional gauge theories whose phase diagram contains phases with deconfined electric and/or magnetic charges. In theories with only either abelian electric or magnetic charges, our construction is an euclidean version of Dira

Gyorgy Szabo, Maria Augusta Santos

Using Monte Carlo simulations we have studied the transition from an "active" steady state to an absorbing "inactive" state for two versions of the branching annihilating random walks with parity conservation on a square lattice. In the first model the randomly walking particles annihilate when they meet and the branching process creates two

D. Lacoste, B. A. van Tiggelen

We derive an expression for the transport mean free path $\ell^*_\perp$ associated with magneto-transverse light diffusion for a random collection of Faraday-active Mie scatterers. This expression relates the magneto-transverse diffusion in multiple scattering directly to the magneto-transverse scattering of a single scatterer.

Cong-Feng Qiao, Shou-Hua Zhu

The one-loop supersymmetric QCD corrections to the top quark semileptonic decays $t\to b \bar{l} {ν_l}$ are considered. The corrections are found to reduce the decay width. In the still acceptable parameter space the corrections to the percentage change in top quark semileptonic decay width can reach the level of -0.7%.

J. Hwang, H. Noh

In this paper we address two points concerning the Sachs-Wolfe effect: (i) the gauge independence of the observable temperature anisotropy, and (ii) a gauge-invariant expression of the effect considering the most general situation of hydrodynamic perturbations. The first result follows because the gauge transformation of the temperature fluctuation at the ob

Yoshihiko Nonomura, Xiao Hu, Masashi Tachiki

The mechanism of the flux-line-lattice (FLL) melting in anisotropic high-T_c superconductors in ${\bf B}\parallel {\bf \hat{c}}$ is clarified by Monte Carlo simulations of the 3D frustrated XY model. The percentage of entangled flux lines abruptly changes at the melting temperature T_m, while no sharp change can be found in the number and size distribution o

Shahar Hod

During the last twenty-five years evidence has been mounting that a black-hole surface area has a {\it discrete} spectrum. Moreover, it is widely believed that area eigenvalues are {\it uniformally} spaced. There is, however, no general agreement on the {\it spacing} of the levels. In this letter we use Bohr's correspondence principle to provide this mis

M. Markevitch, C. L. Sarazin, A. Vikhlinin

We present ASCA gas temperature maps of the nearby merging galaxy clusters Cygnus A, A3667, and A2065. Cygnus A appears to have a particularly simple merger geometry that allows an estimate of the subcluster collision velocity from the observed temperature variations. We estimate it to be ~2000 km/s. Interestingly, this is similar to the free-fall velocity t

F. Dahia, C. Romero

We investigate how the gravitational field generated by line sources can be characterized in Brans-Dicke theory of gravity. Adapting an approach previously developed by Israel who solved the same problem in general relativity we show that in Brans-Dicke theory's case it is possible to work out the field equations which relate the energy-momentum tensor o

Chao-Shang Huang, Shou-Hua Zhu

We explore the discovery potential of the supersymmetric Higgs bosons through $bg$ channel at Tevatron and LHC. Compared with the process of $qq' \to WH$, this channel is more advantigeous to finding the supersymmetric Higgs bosons at Tevatron if $\tanβ$ is larger than ten.

Priyamvada Natarajan, Philip J. Armitage

Warped accretion discs in Active Galactic Nuclei (AGN) exert a torque on the black hole that tends to align the rotation axis with the angular momentum of the outer disc. We compute the magnitude of this torque by solving numerically for the steady state shape of the warped disc, and verify that the analytic solution of Scheuer and Feiler (1996) provides an

Saburo Higuchi

A Hamiltonian cycle of a graph is a closed path that visits every vertex once and only once. It serves as a model of a compact polymer on a lattice. I study the number of Hamiltonian cycles, or equivalently the entropy of a compact polymer, on various lattices that are not homogeneous but with a sublattice structure. Estimates for the number are obtained by

Tomomi Muto

We study D-branes on a three complex dimensional nonabelian orbifold ${\bf C}^3/\Gamma$ with $\Gamma$ a finite subgroup of SU(3). We present general formulae necessary to obtain quiver diagrams which represent the gauge group and the spectrum of the D-brane worldvolume theory for dihedral-like subgroups $\Delta(3n^2)$ and $\Delta(6n^2)$. It is found that the

Enrique Gaztanaga, Rupert A. C. Croft

We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$α$ Forest. We make use of the correlation between the Lyman-$α$ optical depth and the underlying matter density predicted by gravitational instability theory and seen in numerical hydrodynamic simulations. We have modelled t

V. M. Red'kov

Some attention in the literature has been given to the case of a particle of spin 1/2 on the background of the external monopole potential. Some aspects of this problem are reexamined here. The primary technical novelty is that the tetrad generally relativistic method of Tetrode-Weyl-Fock-Ivanenko for describing a spinor particle is exploited. The choice of

V. Buzek, G. Drobny, Min Gyu Kim, M. Havukainen

We present results of numerical investigation of a microscopic dynamics of a two-level atom embedded into a ``linear crystal'' of other two-level atoms. These additional atoms play a role of a material media. All atoms interact with a multimode cavity field. We study how the decay of the initially excited atom is affected by the presence of material

Taksu Cheon, T. Shigehara, K. Takayanagi

We prove that the separable and local approximations of the discontinuity-inducing zero-range interaction in one-dimensional quantum mechanics are equivalent. We further show that the interaction allows the perturbative treatment through the coupling renormalization. Keywords: one-dimensional system, generalized contact interaction, renormalization, perturba

A. S. Omelaenko, Yu. P. Peresunko, Yu. M. Ranyuk, I. M. Shapoval

Polarization characteristics of the gamma beam obtained by the Compton back scattering of laser photons on high energy electrons are evaluated by Monte-Carlo simulations. It is assumed that outgoing photons are tagged; the energy dispersion of the tagging photons and emittance of the initial electrons are taken into account. Dependence of the final photon po

Peter. C. Tandy

We discuss aspects of a covariant QCD modeling of meson physics by illustrating applications to several coupling constants and form factors. In particular, we cover the $ρππ$ and $π^0 γγ$ interactions, the $ρ$ contribution to the pion charge radius, and $πNN$ coupling.

Anders Gardestig, Goran Faldt, Colin Wilkin

A model for the d d -> alpha pi pi reaction, based on two parallel N N -> d pi reactions, is extended to incorporate a complete set of input amplitudes. While low-energy cross sections are underestimated, the rich structure observed in the alpha-particle momentum distributions for 0.8 < T_d < 1.9 GeV (the ABC effect) is extraordinarily well reproduced. In ad

C. L. Korpa, A. E. L. Dieperink

Using a self-consistent delta-hole model the pion propagation in isospin asymmetric nuclear matter is studied. In neutron-rich matter, corresponding to heavy nuclei, a significant difference in positive and negative pion light-cone distributions is obtained leading to a nuclear enhancement of up antiquark distribution compared to the down antiquark one. This

T. Gross-Boelting, C. Fuchs, Amand Faessler

We investigate nuclear matter properties in the relativistic Brueckner approach. The in-medium on-shell T-matrix is represented covariantly by five Lorentz invariant amplitudes from which we deduce directly the nucleon self-energy. To enforce correct Hartree-Fock results we develop a subtraction scheme which treats the bare nucleon-nucleon potential exactly

C. Fuchs, Amand Faessler, Z. S. Wang, T. Gross-Boelting

The influence of the chiral mean field on the collective motion of kaons in relativistic heavy ion reactions at SIS energies is investigated. We consider three types of collective motion, i.e. the transverse flow, the out-of-plane flow (squeeze-out) and the radial flow. The kaon dynamics is thereby described with a relativistic mean field as it originates fo

Stanislav Spichak, Renat Zhdanov

We construct six multi-parameter families of Hermitian quasi-exactly solvable matrix Schroedinger operators in one variable. The method for finding these operators relies heavily upon a special representation of the Lie algebra o(2,2) whose representation space contains an invariant finite-dimensional subspace. Besides that we give several examples of quasi-

Jean-Francois Burnol

The spectral analysis of the (local) conductor operator H = log(|q|) + log(|p|) was shown in a previous paper to be given by the Explicit Formula. I give here the spectral analysis of the commutator operator K = i[log(|p|),log(|q|)] (which shares with H the property of complete dilation invariance). Its spectral function is found to be the derivative of the

M. Rudelson

Let $K, D$ be $n$-dimensional convex bodes. Define the distance between $K$ and $D$ as $$ d(K,D) = \inf \{λ| T K \subset D+x \subset λ\cdot TK \}, $$ where the infimum is taken over all $x \in R^n$ and all invertible linear operators $T$. Assume that 0 is an interior point of $K$ and define $$ M(K) =\int_{S^{n-1}} \| ω\|_K d μ(ω), $$ where $μ$ is the uniform

M. Rudelson

Let $K$ be an $n$-dimensional convex body. Define the difference body by $$ K-K= \{x-y \mid x,y \in K \}. $$ We estimate the volume of the section of $K-K$ by a linear subspace $F$ via the maximal volume of sections of $K$ parallel to $F$. We prove that for any $m$-dimensional subspace $F$ there exists $x \in R^n$, such that $$ vol ((K-K) \cap F) \le C^m (\m

Eric M. Opdam

These are the lecture notes of a series of lectures on Dunkl operators. We discuss the underlying algebraic structure of the degenerate double affine Hecke algebra, intertwiners and shift operators. We apply this to Macdonald theory. We also discuss the ``compact&#39;&#39; and ``noncompact&#39;&#39; spectral decomposition of these operators. In the attractiv

Konrad Schmuedgen

The paper deals with three topics on coquasitriangular bialgebras. A characterization of universal r-forms in terms of Yetter-Drinfeld modules is given. All universal r-forms for the coordinate Hopf algebras of the quantum groups GL_q(N), SL_q(N), O_q(N) and Sp_q(N) are described. It is well-known that the square of the antipode of a coquasitriangular Hopf a

Michael Thaddeus

The moduli space of flat SU(2) connections on a punctured surface, having prescribed holonomy around the punctures, is a compact smooth manifold if the prescription is generic. This paper gives a direct, elementary proof that the trace of the holonomy around a certain loop determines a Bott-Morse function on the moduli space which is perfect, meaning that th

L. Lapointe, J. Morse

The Macdonald polynomials expanded in terms of a modified Schur function basis have coefficients called the $q,t$-Kostka polynomials. We define operators to build standard tableaux and show that they are equivalent to creation operators that recursively build the Macdonald polynomials indexed by two part partitions. We uncover a new basis for these particula

M. A. Aguilar, M. Socolovsky

We study the topological structure of the symmetry group of the standard model, $G_{SM}=U(1)\times SU(2)\times SU(3)$. Locally, $G_{SM}\cong S^1\times (S^3)^2\times S^5$. For SU(3), which is an $S^3$ bundle over $S^5$ (and therefore a local product of these spheres) we give a canonical gauge i.e. a canonical set of local trivializations. These formulae give

Kazuo Fujikawa

An attempt is made at a systematic approach to anomaly matching problem in non-Abelian electric-magnetic duality in N=1 supersymmetric QCD. A strategy we employ is somewhat analogous to anomaly analyses in grand unified models where the anomaly cancellation becomes more transparent if one embeds SU(5) multiplets into a multiplet of (anomaly-free) SO(10). A c

Yong-Wan Kim, Seung-Kook Kim, Young-Jai Park

We show how to systematically derive the exact form of local symmetries for the abelian Proca and CS models, which are converted into first class constrained systems by the BFT formalism, in the Lagrangian formalism. As results, without resorting to a Hamiltonian formulation we obtain the well-known U(1) symmetry for the gauge invariant Proca model, while sh

Eric D&#39;Hoker, Daniel Z. Freedman

The scalar field exchange diagram for the correlation function of four scalar operators is evaluated in anti-de Sitter space, $AdS_{d+1}$. The conformal dimensions $Δ_i$, $i=1,...,4$ of the scalar operators and the dimension $Δ$ of the exchanged field are arbitrary, constrained only to obey the unitarity bound. Techniques similar to those developed earlier f

Adam F. Falk

An overview of the theory of B physics is given, with an emphasis on issues in the strong interactions and hadronic physics. This article is taken from an introductory chapter of The BaBar Physics Book - Physics at an Asymmetric B Factory, SLAC Report SLAC-R-504. It is written at the level of a basic survey aimed at the experimental community.

Michael Chanowitz

The nature of electroweak symmetry breaking can only be established definitively by the direct discovery and detailed study of the symmetry breaking quanta at high energy colliders. At the LHC the ability to observe TeV scale strong WW scattering confers a no-lose capability to establish the mass scale and interaction strength of the symmetry breaking quanta

D. Kharzeev

This summary is an attempt to overview the wealth of new results and ideas in quarkonium physics presented at the Seattle Workshop.

T. M. Aliev, M. Savci, ; F. Yasuk

The strong coupling constant g_(Ko* K pi) of the scalar Ko* meson decay to (K pi) is calculated in light cone QCD sum rule. The predicted value of the coupling constant g_(Ko* K pi) is in a good agreement with the experimental result.

N. N. Nikolaev, A. V. Pronyaev, B. G. Zakharov

We propose a new method of the determination of $R^{D}=\sigma_{L}^{D}/\sigma_{T}^{D}$ from the dependence of the diffractive cross section on the azimuthal angle between the electron scattering and proton scattering planes. The method is based on our finding of the model independence of the ratio of the $LT$ interference and transverse diffractive structure

Peter Lichard

We derive a set of new formulas for various distributions in dilepton production via virtual photon bremsstrahlung from pseudoscalar mesons and unpolarized spin-one-half fermions. These formulas correspond to the leading and sub-leading terms in the Low-Burnett-Kroll expansion for real photon bremsstrahlung. The relation of our leading-term formulas to previ

Nicolao Fornengo

Recently the DAMA/NaI Collaboration reported further indication of a possible modulation effect in WIMP direct detection. In this note we discuss the relevance of this result for supersymmetric theories where the neutralino is the dark matter candidate. We specifically consider the Minimal Supersymmetric extension of the Standard Model (MSSM) and Supergravit

Debajyoti Choudhury, B. Dutta, Anirban Kundu

We examine the large branching ratio for the process $B\to η^{\prime} K$ from the standpoint of R parity violating supersymmetry. We have given all possible $R_p$ violating contributions to $B\to η^{\prime} K$ amplitudes. We find that only two pairs of $λ^{\prime}$-type $R_p$ violating couplings can solve this problem after satisfying all other experimental

Edward Witten

Synthesizing older ideas about the 1/N expansion in gauge theory, the quantum mechanics of black holes, and quantum field theory in Anti de Sitter space, a new correspondence between gauge theory and quantum gravity has illuminated both subjects.

D. L. Khokhlov

The theory of gravity without free gravitational fields is considered. It is assumed that gravitational radiation is some hypothetical matter fields. Gravitational emission is a process of the decay of proton into hypothetical matter fields at the Planck scale.

Peter Lichard

The glob model of Lichard and Van Hove and the modified soft annihilation model (MSAM) of Lichard and Thompson are used as a phenomenological tool for relating results from various experiments on soft photon production in high energy collisions. The total phenomenological expectation is composed of contributions from classical bremsstrahlung, the soft annihi

York Schroder

We evaluate the static QCD potential to two--loop order. Compared to a previous calculation a sizable reduction of the two--loop coefficient $a_2$ is found.