February 1998 arXiv papers — page 6

Peter J. Wheatley

I present pointed ROSAT PSPC observations of the pre-cataclysmic binary V471 Tauri. The hard X-ray emission (>0.4keV) is not eclipsed by the K star, demonstrating conclusively that this component cannot be emitted by the white dwarf. Instead I show that its spectrum and luminosity are consistent with coronal emission from the tidally spun-up K star. The star

K. D. Gordon, G. C. Clayton, T. L. Smith, J. P. Aufdenberg

We have used spectra taken between 1992 and 1997 to derive the spectroscopic orbit of the eclipsing double-lined spectroscopic binary HD 197770. This binary has a period of 99.69 +/- 0.02 days and K amplitudes of 31.2 +/- 0.8 and 47.1 +/- 0.4 km s^{-1} for components A & B, respectively. The msin^{3}i values for A & B are 2.9 and 1.9, respectively, and are c

P. Jablonka, E. Bica, C. Bonatto, T. J. Bridges

This paper presents 3600-5400 Angstroms integrated spectra of 19 globular clusters (or candidates) projected on the central regions of M31, r <=5.3 arcmin (approx 1.2 kpc). We check the cluster nature of these objects, and derive their ages, metallicities and reddenings. From the initial sample, 16 objects turn out to be true star clusters, two are Galactic

Andrew A. de Laix, Glenn D. Starkman

We analyze the window functions for the spherical harmonic mode estimators of all--sky, volume limited surveys considering evolutionary effects along the past light--cone which include the deviation of the distance scale from a linear relationship with redshift, linear peculiar velocity corrections, and linear evolution of the density perturbations. The sphe

Daniele Fargion, Arnon Dar

Recent observations suggest that many planetary-mass objects may be present in the outer solar system between the Kuiper belt and the Oort cloud. Gravitational perturbations may occasionally bring them into the inner solar system. Their passage near Earth could have generated gigantic tidal waves, large volcanic eruptions, sea regressions, large meteoritic i

J. R. Herrnstein, L. J. Greenhill, J. M. Moran, P. J. Diamond

We report a 3 sigma upper limit of 220 microJanskys on any 22-GHz continuum emission coincident with the central engine in NGC 4258. If NGC 4258 is powered by an advection-dominated accretion flow, this radio upper limit implies that the inner advection-dominated flow cannot extend significantly beyond about 100 Schwarzschild radii.

James R. Graham, Lynne A. Hillenbrand, Anthony A. Misch

We describe a system in use at the Lick Observatory 1-m Nickel telescope for near-simultaneous imaging at optical and near-infrared wavelengths. The combined availability of a CCD and a NICMOS-3 camera makes the system well-suited for photometric monitoring from 0.5-2.2 microns of a variety of astrophysical objects. Our science program thus far has concentra

Giovanni Moriondo, Carlo Giovanardi, Leslie K. Hunt

We present mass distributions obtained from near-infrared (NIR) surface brightness decompositions and rotation curve fitting of a sample of early-type spiral galaxies. Bulge and disk mass-to-light (M/L) ratios, dark halo parameters, and the modified Newtonian dynamics (MOND) acceleration parameter are derived. We find that the mean disk NIR M/L is higher tha

Kunihiko Kaneko

Basic problems for the construction of a scenario for the Life are discussed. To study the problems in terms of dynamical systems theory, a scheme of intra-inter dynamics is presented. It consists of internal dynamics of a unit, interaction among the units, and the dynamics to change the dynamics itself, for example by replication (and death) of units accord

M. Haskins, J. M. Speight

Existence of breather (spatially localized, time periodic, oscillatory) solutions of the topological discrete sine-Gordon (TDSG) system, in the regime of weak coupling, is proved. The novelty of this result is that, unlike the systems previously considered in studies of discrete breathers, the TDSG system does not decouple into independent oscillator units i

V. P. Gusynin, V. A. Miransky, A. V. Shpagin

The effective action for local composite operators in $QED_3$ is considered. The effective potential is calculated in leading order in $1/N_f$ ($N_f$ is the number of fermion flavors) and used to describe the features of the phase transition at $N_f=N_{\rm cr}$, $3<N_{\rm cr}<5$. It is shown that this continuous phase transition satisfies the criteria of the

E. Marinari, G. Parisi, J. J. Ruiz-Lorenzo

We characterize numerically the properties of the phase transition of the three dimensional Ising spin glass with Gaussian couplings and of the low temperature phase. We compute critical exponents on large lattices. We study in detail the overlap probability distribution and the equilibrium overlap-overlap correlation functions. We find a clear agreement wit

A. A. Tseytlin

We find the general expression for the open superstring partition function on the annulus in a constant abelian gauge field background and at finite temperature. We use the approach based on Green-Schwarz string path integral in the light-cone gauge and compare it with NSR approach. We discuss the super Yang-Mills theory limit and mention some D-brane applic

I. F. Ginzburg, I. P. Ivanov, A. Schiller

If next generations of heavy quarks and leptons exist within the standard model (SM), they can manifest themselves in Higgs boson production at the Tevatron and the LHC, before being actually observed. This generation leads to an increase of the Higgs boson production cross section via gluon fusion at hadron colliders by a factor 6-9. So, the study of this p

A. D. Martin, M. G. Ryskin

We perform an exploratory study of higher twist contributions to deep inelastic scattering. We estimate the size of two major sources of higher twist, namely absorptive corrections and the vector meson dominance (VMD) contribution. We find that they give a sizeable higher twist component of F_2. For example at x = 0.01 it is about 8% (17%) at Q^2 = 10 GeV^2

Michael J. W. Hall

Consider the question: what statistical ensemble corresponds to minimal prior knowledge about a quantum system ? For the case where the system is in fact known to be in a pure state there is an obvious answer, corresponding to the unique unitarily-invariant measure on the Hilbert sphere. However, the problem is open for the general case where states are desc

Jan B. Rehm, Karsten Jedamzik

We investigate Big Bang nucleosynthesis (hereafter, BBN) in a cosmic environment characterized by a distribution of small-scale matter/antimatter domains. Production of antimatter domains in a baryo-asymmetric universe is predicted in some electroweak baryogenesis scenarios. We find that cosmic antimatter domains of size exceeding the neutron-diffusion lengt

P. Haegler, A. Schaefer

Based on a sumrule for the nucleon spin we expand quark and gluon orbital angular momentum operators and derive an evolution matrix for higher moments of the corresponding distributions. In combination with the spin-dependent DGLAP-matrix we find a complete set of spin and orbital angular momentum evolution equations.

Idit Zehavi, Adam G. Riess, Robert P. Kirshner, Avishai Dekel

We analyze the monopole in the peculiar velocities of 44 Type Ia supernovae (SNe Ia) to test for a local void. The sample extends from 20 to 300 Mpc/h, with distances, deduced from light-curve shapes, accurate to ~6%. Assuming Omega_m=1 and Omega_lambda=0, the most significant deviation we find from the Hubble law is an outwards flow of (6.6+/-2.2)% inside a

Pedro Bicudo

We introduce coupled channels of Bethe-Salpeter mesons both in the boundstate equation for mesons and in the mass gap equation for chiral symmetry. Consistency is insured by the Ward Identities for axial currents, which preserve the Goldstone boson nature of the pion and prevents a systematic shift of the hadron spectrum. We study the decay of a scalar meson

Tooru Tsuchida, Go Kawamura, Kazuya Watanabe

We derive a modified Buchdahl inequality for scalar-tensor theories of gravity. In general relativity, Buchdahl has shown that the maximum value of the mass-to-size ratio, $2M/R$, is 8/9 for static and spherically symmetric stars under some physically reasonable assumptions. We formally apply Buchdahl&#39;s method to scalar-tensor theories and obtain theory-

Ping He, Yuan-Zhong Zhang

The explanation for the existence of an excess population of faint blue galaxies (FBGs) has been a mystery for nearly two decades, and remains one of the grand astronomical issues to date. Existing models cannot explain all of the observational data such as galaxy number counts in the optical and infrared passbands and the redshift distributions of galaxies.

R. W. Spekkens, J. E. Sipe

We show how fragmentation of a Bose-Einstein condensate can occur given repulsive inter-particle interactions and a non-uniform external potential.

Avinash Khare, Uday P. Sukhatme

We present an exact solution of the three-body scattering problem for a one parameter family of one dimensional potentials containing the Calogero and Wolfes potentials as special limiting cases. The result is an interesting nontrivial relationship between the final momenta $p&#39;_i$ and the initial momenta $p_i$ of the three particles. We also discuss anot

L. Vaidman

Counterfactuals in quantum theory are briefly reviewed and it is argued that they are very different from counterfactuals considered in the general philosophical literature. The issue of time symmetry of quantum counterfactuals is considered and a novel time-symmetric definition of quantum counterfactuals is proposed. This definition is applied for analyzing

C. P Sun, H. Zhan, X. F, Liu

The possible effect of environment on the efficiency of a quantum algorithm is considered explicitely. It is illustrated through the example of Shor&#39;s prime factorization algorithm that this effect may be disastrous. The influence of environment on quantum computation is probed on the basis of its analogy to the problem of wave function collapse in quant

Valeri V. Dvoeglazov

Quantum electrodynamics is the well-accepted theory. However, we feel it is useful to look at formalisms that provide alternative ways to describe light, because in the recent years the development of quantum field theories based primarily on the gauge principle has encountered considerable difficulties. There is a wide variety of generalized theories and th

G. A. Kotel&#39;nikov

It is shown that the universal Newton time may be introduced in the classical electrodynamics. The statement results from an existence of the generalized symmetry of Maxwell equations with respect to Galilei transformations (physics/9701006). In the case of the extended Galilei transformations the postulate of invariance of the speed of light may be made com

Takahiro Hatano, Shin-ichi Sasa

We present a computational model for Szilard&#39;s engine and the information discarding process. Taking advantage of a fact that the one is essentially the reversed cycle of the other, we can discuss the both by employing the same model. Through numerical simulations we calculate the work extracted by the engine and the heat generation in the information di

Nimai C. Mukhopadhyay, H. C. Chiang, S. K. Singh, E. Oset

We study total muon capture rates in light nuclei, taking into account renormalizations of the nuclear vector and axial vector strengths. We estimate the influence in the results of uncertainties of the spin-isospin interaction parameter and nuclear densities. A few of these reactions are theoretical benchmarks for physics involving searches for neutrino osc

S. K. Singh, Nimai C. Mukhopadhyay, E. Oset

We study inclusive nu_e and nu_mu cross sections in C-12 in a theory that takes into account significant nuclear renormalization of strengths. Our calculation is in excellent agreement with the measured inclusive muon capture rate and the flux-averaged nu_e cross section, but overestimates the flux-averaged nu_mu inclusive cross section. These reactions are

P. F. Bedaque, H. -W. Hammer, U. van Kolck

We report on results of the effective theory method applied to neutron-deuteron scattering. We extend previous results in the $J=3/2$ channel to non-zero energies and find very good agreement with experiment without any parameter fitting.

Maxim Vybornov

We obtain a linear algebra data presentation of the category of constructible with respect to perverse triangulation sheaves on a finite simplicial complex. We also establish Koszul duality between the above mentioned category and the category of perverse sheaves constructible with respect to the triangulation

Jose Burillo

The goal of this paper is to construct quasi-isometrically embedded subgroups of Thompson&#39;s group $F$ which are isomorphic to $\fz^n$ for all $n$. A result estimating the norm of an element of Thompson&#39;s group is found. As a corollary, Thompson&#39;s group is seen to be an example of a finitely presented group which has an infinite-dimensional asympt

Vladimir Shpilrain

It is a well-known fact that every group $G$ has a presentation of the form $G = F/R$, where $F$ is a free group and $R$ the kernel of the natural epimorphism from $F$ onto $G$. Driven by the desire to obtain a similar presentation of the group of automorphisms $Aut(G)$, we can consider the subgroup $Stab(R) \subseteq Aut(F)$ of those automorphisms of $F$ th

B. Shapiro, M. Shapiro, A. Vainshtein

We prove that the number of connected components in the intersection of two open opposite Schubert cells in the variety of complete real n-dimensional flags equals 3*2^{n-1} for n>5.

Ivan Fesenko

The wild group is the group of wild automorphisms of a local field of characteristic p. In this paper we apply Fontaine-Wintenberger&#39;s theory of fields of norms to study the structure of the wild group. In particular we provide a new short proof of R. Camina&#39;s theorem which says that every pro-p-group with countably many open sugroups is isomorphic t

Wellington da Cruz

We obtain for any spin, $s$, the Hausdorff dimension, $h_{i}$, for fractional spin particles and we discuss the connection between this number, $h_{i}$, and the Chern-Simons potential. We also define the topological invariants, $W_s$, in terms of the statistics of these particles.

Feodor A. Smirnov

We construct the quasi-classical approximation of the form factors in finite volume using the separation of variables. The latter is closely related to the Baxter equation.

Theodora Ioannidou, Wojtek Zakrzewski

A one parameter generalization of Ward&#39;s chiral model in 2+1 dimensions is given. Like the original model the present one is integrable and possesses a positive-definite and conserved energy and $y$-momentum. The details of the scattering depend on the value of the parameter of the generalisation.

B. B. Deo

An open string in four dimensions is supplemented by forty four Majorana fermions. The fermions are grouped in such a way that the resulting action is supersymmetric. The super-Virasoro algebra is constructed and closed by the use of Jacobi identity. The tachyonic ground state decouples from the physical states. After a GSO projection, the resulting physical

Haru-Tada Sato, Michael G. Schmidt

Counting the contribution rate of a world-line formula to Feynman diagrams in $ϕ^3$ theory, we explain the idea how to determine precise combinatorics of Bern-Kosower-like amplitudes derived from a bosonic string theory for $N$-point two-loop Feynman amplitudes. In this connection we also present a method to derive simple and compact world-line forms for the

Estia Eichten, Kenneth Lane, John Womersley

In modern technicolor models, there exist very narrow spin-zero and spin-one neutral technihadrons---$pi^0_T$, $rho^0_T$ and $omega_T$---with masses of a few 100 GeV. The large coupling of $π^0_T$ to $μ^+μ^-$, the direct coupling of $rho^0_T$ and $omega_T$ to the photon and $Z^0$, and the superb energy resolution of the First Muon Collider may make it possib

A. Ghinculov, T. Binoth, J. J. van der Bij

In view of recent perturbative and nonperturbative evidence that the peak of the Higgs resonance saturates as the coupling increases, we examine the potential of the future Large Hadron Collider to discover a heavy Higgs resonance by gluon fusion.

A. Pineda, J. Soto

The matching coefficients for the four-quark operators in NRQCD (NRQED) are calculated at one loop using dimensional regularization for ultraviolet and infrared divergences. The matching for the electromagnetic current follows easily from our results. Both the unequal and equal mass cases are considered. The role played by the Coulomb infrared singularities

Joan Sola

We compare the standard top quark decay and the charged Higgs decay of the top quark, t --> W+ b and t --> H+ b, at the quantum level in the MSSM. While the SUSY loop corrections to the standard top quark decay are only of a few percent, it turns out that t --> H+ b is a most promising candidate for carrying large quantum SUSY signatures. As a result, the (t

D. Delepine, J. -M. Gerard, J. Pestieau, J. Weyers

A simple Regge pole model for $Kπ$ scattering explains the large $e^{i δ}$ between isospin amplitudes which is observed at the D meson mass ($δ\approx π/2$). It predicts $δ\approx 14^{\circ}- 20^{\circ}$ at the B mass. Implications for ($B \to K π$) decays and extensions of the model to other two-body decay channels are briefly discussed.

J. Y. Cui, H. Y. Jin, J. M. Wu

We construct the B.S. equation for the hybrid mesons under instantaneous approximation. The kernel is chosen as the sum of an one-gluon exchange potential and a linear confining potential. The equations are solved by numerical method, and the spectrum of hybrid mesons $b\bar{b}g$ and $c\bar{c}g$ are obtained.

Arcadi Santamaria, German Rodrigo, Mikhail Bilenky

The importance of measuring the b-quark mass at different scales is emphasized. The recent next-to-leading order calculation of three jet heavy quark production at LEP and its use to measure $m_b(m_Z)$ is discussed.

Christopher Kolda, John March-Russell

The phenomenology of supersymmetric models of inflation, where the inflationary vacuum energy is dominated by D-terms of a U(1), is investigated. Particular attention is paid to the questions of how to arrange for sufficient e-folds of inflation to occur, what kind of thermal history is expected after the end of inflation, and how to implement successful bar

T. Onogi

I report the current status of the heavy-light decay constants, the bag parameters and the semileptonic form factors. I compare the heavy-light decay constants with Wilson-Wilson and clover-clover fermions. Systematic errors such as scale setting and renormalization factors are also discussed. 1/M dependences for the heavy-light semileptonic form factors nea

Dominic Clancy, James E. Lidsey, Reza Tavakol

The concept of scale factor duality is considered within the context of the spatially homogeneous, vacuum Brans-Dicke cosmologies. In the Bianchi class A, it is found that duality symmetries exist for the types I, II, VI_0, VII_0, but not for types VIII and IX. The Kantowski-Sachs and locally rotationally symmetric Bianchi type III models also exhibit a scal

D. Clancy, J. E. Lidsey, R. Tavakol

A class of exact, anisotropic cosmological solutions to the vacuum Brans-Dicke theory of gravity is considered within the context of the pre-big bang scenario. Included in this class are the Bianchi type III, V and VI_h models and the spatially isotropic, negatively curved Friedmann-Robertson-Walker universe. The effects of large anisotropy and spatial curva

Gerhard Lessner

A scenario of galaxy formation is put forward which is a process of sudden condensation just after recombination. It is essentially based on the fact that the cosmic matter gas after recombination is a general relativistic Boltzmann gas which runs within a few $10^6$ years into a state very close to collision--dominated equilibrium. The mass spectrum of axia

Miquel Dorca

In a recent work an approximation procedure was introduced to calculate the vacuum expectation value of the stress-energy tensor for a conformal massless scalar field in the classical background determined by a particular colliding plane wave space-time. This approximation procedure consists in appropriately modifying the space-time geometry throughout the c

Daniel ben-Avraham

We study diffusion-limited coalescence, A+A<-->A$, in one dimension, and derive an exact solution for the steady state in the presence of a trap. Without the trap, the system arrives at an equilibrium state which satisfies detailed balance, and can therefore be analyzed by classical equilibrium methods. The trap introduces an irreversible element, and the st

Jacek Dziarmaga

A quench in an overdamped one dimensional $ϕ^4$ model is studied by analytical and numerical methods. For an infinite system or a finite system with free boundary conditions, the density of kinks after the transition is proportional to the eighth root of the rate of the quench. For a system with periodic boundary conditions, it is proportional to the fourth

B. Doucot, P. Simon

We study in this paper the Heisenberg antiferromagnet with nearest neighbours interactions on the Husimi cactus, a system which has locally the same topology as the Kagomé lattice. This system has a huge classical degeneracy corresponding to an extensive number of degrees of freedom.We show that unlike thermal fluctuations, quantum fluctuations lift partiall

Nicola Marzari, David Vanderbilt

The electronic ground state of a periodic crystalline solid is usually described in terms of extended Bloch orbitals; localized Wannier functions can alternatively be used. These two representations are connected by families of unitary transformations, carrying a large degree of arbitrariness. We have developed a localization algorithm that allows one to ite

L. Bellaiche, J. Padilla, David Vanderbilt

First-principles calculations are performed to investigate alloying and ferroelectric effects in lead zirconate titanate (PZT) with high Ti composition. We find that the main effect of alloying in the paraelectric phase of PZT is the existence of two sets of B-O bonds, i.e., shorter Ti-O bonds vs. longer Zr-O bonds. On the other hand, ferroelectricity leads

Alberto Garcia, David Vanderbilt

Monte Carlo simulations with an effective Hamiltonian parametrized from first principles are performed to study the dielectric response of BaTiO3 as a function of temperature, with particular emphasis on the behavior of the dielectric constant near the transition from the ferroelectric tetragonal phase to the paraelectric cubic phase.

J. Padilla, David Vanderbilt

We present first-principles total-energy calculations of (001) surfaces of SrTiO3. Both SrO-terminated and TiO2-terminated surfaces are considered, and the results are compared with previous calculations for BaTiO3 surfaces. The major differences are in the details of the relaxed surface structures. Our calculations argue against the existence of a large fer

Wolfgang Koch, Volker Dohm

We present the first analytic study of finite-size effects on critical diffusion above and below T_c of three-dimensional Ising-like systems whose order parameter is coupled to a conserved density. We also calculate the finite-size relaxation time that governs the critical order-parameter relaxation towards a metastable equilibrium state below T_c. Two new u

Eugene V. Ivashkevich, Alexander M. Povolotsky, Alessandro Vespignani, Stefano Zapperi

The general framework for the renormalization group analysis of self-organized critical sandpile models is formulated. The usual real space renormalization scheme for lattice models when applied to nonequilibrium dynamical models must be supplemented by feedback relations coming from the stationarity conditions. On the basis of these ideas the Dynamically Dr

J. Ambjorn, A. Avakyan, T. Hakobyan, A. Sedrakyan

We have constructed a one dimensional exactly solvable model, which is based on the t-J model of strongly correlated electrons, but which has additional quantum group symmetry, ensuring the degeneration of states. We use Bethe Ansatz technique to investigate this model. The thermodynamic limit of the model is considered and equations for different density fu

M. Pleimling, B. Neubert, R. Siems

The low temperature behaviour of the four-state chiral clock ($CC_4$) model is reexamined using a systematic low temperature series expansion of the free energy. Previously obtained results for the low temperature phases are corrected and the low temperature phase diagram is derived. In addition, the phase transition from the modulated region to the high tem

M. Brian Maple

The current status of basic research on the high temperature cuprate superconductors and prospects for technological applications of these materials is discussed. Recent developments concerning other novel superconductors are also briefly described.

J. Bachteler, H. -R. Trebin

The elastic theory of quasicrystals considers, in addition to the normal displacement field, three phason degrees of freedom. We present an approximative solution for the elastic Green&#39;s function of icosahedral quasicrystals, assuming that the coupling between the phonons and phasons is small.

Mahn-Soo Choi, M. Y. Choi, Sung-Ik Lee

We consider two chains of ultrasmall Josephson junctions, coupled capacitively with each other, and investigate the transport of particle-hole pairs and the quantum phase transitions at zero temperature. For appropriate parameter ranges, the particle-hole pairs are found to play major roles in transport phenomena; condensation of such pairs leads to the supe

Ross H. McKenzie

This ``Perspective&#39;&#39; briefly reviews recent work showing that a class of organic superconductors have important similarities to the cuprate superconductors: (i) There is competition betweeen superconductivity and antiferromagnetism. (ii) Uncoventional metallic behavior is observed near the metal-insulator transition. A more detailed review and discus

Lan Yin, Matthias Troyer, Sudip Chakravarty

The spin-spin correlation length and the static structure factor for bilayer antiferromagnets, such as YBa$_2$Cu$_3$O$_{6}$, are calculated using field theoretical and numerical methods. It is shown that these quantities can be directly measured in neutron scattering experiments using energy integrated two-axis scan despite the strong intensity modulation pe

Tarun Souradeep, J. Richard Bond, Lloyd Knox, George Efstathiou

We present the status of our study into the feasibility of estimating the parameters of inflation from planned satellite observations of the anisotropy of the cosmic microwave background (CMB).We describe a perturbative procedure for studying inflation models with soft departures from scale free spectra and find that in this case the parameters of inflation

X. Hernandez, Gerard Gilmore

We present a simplified analytic approach to the problem of the spiraling of a massive body orbiting within the dark halo of a dwarf galaxy. This dark halo is treated as the core region of a King distribution of dark matter particles, in consistency with the observational result of dwarf galaxies having solid body rotation curves. Thus we derive a simple for

David H. Hughes, James S. Dunlop

New bolometer arrays operating on the world&#39;s largest sub-mm and mm telescopes offer a unique view of the high-redshift universe with unprecedented sensitivity. Recent sub-millimetre continuum studies show that the host galaxies of many luminous high-redshift AGN (radio galaxies and radio-quiet quasars) radiate strongly at rest-frame far-infrared wavelen

Yong-Zhong Qian

Here I review some nuclear physics aspects of core-collapse supernovae concerning neutrinos. Studies of neutrino emission and interactions in supernovae are crucial to our understanding of the explosion mechanism, the heavy element nucleosynthesis, and pulsar proper motions. I discuss the effects of reduced neutrino opacities in dense nuclear matter on super

Franz E. Schunck

We analyze the spherically symmetric Einstein field equation with a massless complex scalar field. We can use the Newtonian solutions to fit the rotation curve data of spiral and dwarf galaxies. From the general relativistic solutions, we can derive high gravitational redshift values.

A. Possenti, M. Colpi, N. D&#39;Amico, L. Burderi

Known millisecond pulsars have periods longer than 1.558 ms. Recycled in binary systems, neutron stars can attain very short spin periods. In this paper we investigate the expected properties of the millisecond pulsar distribution by simulating synthetic populations under different assumptions for the neutron star equation of state and decay of the magnetic

R. Rutledge

The Astronomer&#39;s Telegram (ATEL; http://fire.berkeley.edu:8080/) is a web based short-notice (<4000 characters) publication system for reporting and commenting on new astronomical observations, offering for the first time in astronomy effectively instantaneous distribution of time-critical information for the entire professional community. It is designed

D. de Martino, R. Barcaroli, G. Matt, M. Mouchet

We present BeppoSAX observations of the peculiar long period polar system V1309 Ori (RXJ0515.6+0105). The source was detected simultaneously at soft and, for the first time, at hard X-rays with the LECS and the MECS detectors. Both, the LECS and the MECS light curves are irregular with a bursting/flaring type behaviour indicating inhomogeneous accretion onto

D. Kunth, J. M. Mas-Hesse, E. Terlevich, R. Terlevich

We present high dispersion HST GHRS UV spectroscopic observations of 8 HII galaxies covering a wide range of metallicities and physical properties. We have found Lyalpha emission in 4 galaxies with blueshifted absorption features, leading to PCygni like profiles in 3 of them. In all these objects the OI and S II absorption lines are also blueshifted with res

D. N. Voskresensky, E. E. Kolomeitsev, B. Kaempfer

We consider massive photon decay reactions via intermediate states of electron-electron-holes and proton-proton-holes into neutrino-antineutrino pairs in the course of neutron star cooling. These reactions may become operative in hot neutron stars in the region of proton pairing where the photon due to the Higgs-Meissner effect acquires an effective mass $m_

Kohji Yoshikawa, Makoto Itoh, Yasushi Suto

We have performed a series of simulations of clusters of galaxies on the basis of the smoothed particle hydrodynamics technique in a spatially-flat cold dark matter universe with $Ω=0.3$, $λ=0.7$, and H_0=70 km/s/Mpc as one of the most successful representative cosmological scenarios. In particular, we focus on the Sunyaev--Zel&#39;dovich effect in submm and

Greg Ushomirsky, Lars Bildsten

Several classes of stars (most notably O and B main-sequence stars, as well as accreting white dwarfs and neutron stars) rotate quite rapidly, at spin frequencies greater than the typical g-mode frequencies. We discuss how rapid rotation modifies the $κ$-mechanism excitation and observability of g-mode oscillations. We find that, by affecting the timescale m

R. Brent Tully, M. J. Pierce, J. S. Huang, W. Saunders

Magnitude-limited samples of spiral galaxies drawn from the Ursa Major and Pisces clusters are used to determine their extinction properties as a function of inclination. Imaging photometry is available for 87 spirals in B,R,I and K&#39; bands. Extinction causes systematic scatter in color-magnitude plots. A strong luminosity dependence is found. Relative ed

S. Ferrara, C. Fronsdal

We investigate representations of the conformal group that describe &#34;massless&#34; particles in the interior and at the boundary of anti-de Sitter space. It turns out that massless gauge excitations in anti-de Sitter are gauge &#34;current&#34; operators at the boundary. Conversely, massless excitations at the boundary are topological singletons in the i

Alexander I. Olemskoi, Alexei D. Kiselev

The paper has been withdrawn

Andrija Rasin

I define a set of conditions that the most general hierarchical Yukawa mass matrices have to satisfy so that the leading rotations in the diagonalization matrix are a pair of (2,3) and (1,2) rotations. In addition to Fritzsch structures, examples of such hierarchical structures include also matrices with (1,3) elements of the same order or even much larger t

C. T. H. Davies, K. Hornbostel, G. P. Lepage, A. Lidsey

We present results for the spectrum of b-bbar bound states in the quenched approximation for three different values of the lattice spacing, in the range 0.05fm to 0.15fm. We find our results for spin-independent splittings in physical units to be independent of the lattice spacing, indicating the absence of systematic errors from discretisation effects. Spin

A. Bartl, E. Christova, T. Gajdosik, W. Majerotto

We obtain analytical formulae for the cross section and the angular distributions of the b(bbar) quarks in the process e+e- -> t tbar, with t -> W+ b (tbar -> W- bbar) assuming CP violation in the γt tbar and Z t tbar vertices. We present CP violating asymmetries, which measure separately the real and imaginary parts of the electroweak dipole moment form fac

Mario Vietri

Protons accelerated to high energies in the relativistic shocks that generate gamma ray bursts photoproduce pions, and then neutrinos in situ. I show that ultra high energy neutrinos (> 10^19 eV) are produced during the burst and the afterglow. A larger flux, also from bursts, is generated via photoproduction off CMBR photons in flight but is not correlated

R. H. Sanders, M. A. W. Verheijen

This is the third in a series of papers in which spiral galaxy rotation curves are considered in the context of Milgrom&#39;s modified dynamics (MOND). The present sample of 30 objects is drawn from a complete sample of galaxies in the Ursa Major cluster with photometric data by Tully et al. (1996) and 21 cm line data by Verheijen (1997). The galaxies are ro

U. Fuhrmann, K. Morawetz, R. Walke

The damping rate of hot giant dipole resonances (GDR) is investigated. Besides Landau damping we consider collisions and density fluctuations as contributions to the damping of GDR. Within the nonequilibrium Green&#39;s function method we derive a non-Markovian kinetic equation. The linearization of the latter one leads to complex dispersion relations. The c

V. A. Bednyakov, H. V. Klapdor-Kleingrothaus

Direct dark matter detection is considered in the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The effective neutralino-quark Lagrangian is obtained and event rates are calculated for the Ge-73 isotope. Accelerator and cosmological constraints on the NMSSM parameter space are included. By means of scanning the parameter space at the Fermi scale we

Haye Hinrichsen, Gudrun Schliecker

Voronoi tessellations of scale-invariant fractal sets are characterized by topological and metrical properties that are significantly different from those of natural cellular structures. As an example we analyze Voronoi diagrams of intermittent particle distributions generated by a directed percolation process in (2+1) dimensions. We observe that the average

David Hochberg, Matt Visser

We extend previous proofs that violations of the null energy condition (NEC) are a generic and universal feature of traversable wormholes to completely non-symmetric time-dependent wormholes. We show that the analysis can be phrased purely in terms of local geometry at and near the wormhole throat, and do not have to make any technical assumptions about asym

Steven C. van der Marck

In a recent article, Galam and Mauger proposed an invariant for site and bond percolation thresholds, based on known values for twenty lattices (Eur. Phys. J. B 1 (1998) 255-258). Here we give a larger list of values for more than forty lattices in two to six dimensions. In this list are new results for fcc, bcc, and diamond lattices in 4, 5, and 6 dimension

Goro Hatayama, Anatol N. Kirillov, Atsuo Kuniba, Masato Okado

Let B_{(l)} be the perfect crystal for the l-symmetric tensor representation of the quantum affine algebra U&#39;_q(\hat{sl(n)}). For a partition mu = (mu_1,...,mu_m), elements of the tensor product B_{(mu_1)} \otimes ... \otimes B_{(mu_m)} can be regarded as inhomogeneous paths. We establish a bijection between a certain large mu limit of this crystal and t

V. D. Ivashchuk, V. N. Melnikov

The block-orthogonal generalization of the Majumdar-Papapetrou type solutions for the sigma-model studied earlier are obtained and corresponding solutions with p-branes are considered. The existence of solutions and the number of independent harmonic functions is defined by the matrix of scalar products of vectors $U^s$, governing the sigma-model target spac

Xiang-Bin Wang, C. H. Oh, L. C. Kwek

In a recent paper [Nieto M M 1996 Quantum and Semiclassical Optics, 8 1061; quant-ph/9605032], the one dimensional squeezed and harmonic oscillator time-displacement operators were reordered in coordinate-momentum space. In this paper, we give a general approach for reordering multi-dimensional exponential quadratic operator(EQO) in coordinate-momentum space

J. A. White, C. C. Chow, J. Ritt, C. Soto-Trevino

We study some mechanisms responsible for synchronous oscillations and loss of synchrony at physiologically relevant frequencies (10-200 Hz) in a network of heterogeneous inhibitory neurons. We focus on the factors that determine the level of synchrony and frequency of the network response, as well as the effects of mild heterogeneity on network dynamics. Wit