November 2000 arXiv papers — page 3

S. F. King

In this talk we assume the conventional see-saw mechanism, and contruct a hierarchical pattern of three active neutrinos with bi-maximal mixing. In order to enforce the hierarchy we use the single right handed neutrino dominance mechanism which is a very nice way to ensure a neutrino mass hierarchy in the presence of large mixing angles. We show how this mec

M. Cacciari, V. Del Duca, S. Frixione, Z. Trocsanyi

We compute the order-$\as$ corrections to the total cross section and to jet rates for the process $\epem\to\epem +$ hadrons, where the hadrons are produced through crossed-channel quark exchange in the hard scattering of two off-shell photons originating from the incoming leptons. We use a next-to-leading order general-purpose partonic Monte Carlo event gen

Grahame A. Blair

High precision measurements at the linear collider will allow a model- independent reconstruction of nature at high energy scales. The method of bottom-up extrapolation from the electroweak scale to the GUT scale is explained and both a universal minimal supergravity and a gaugino-mediated model are presented as examples. Comparisons are made with the LHC-on

E. Boos, J. -C. Brient, D. W. Reid, H. J. Schreiber

We examine the prospects for measuring the \gaga branching fraction of a Standard Model-like Higgs boson with a mass of 120 GeV at the future TESLA linear \ee collider, assuming an integrated luminosity of 1 ab$^{-1}$ and center-of-mass energies of 350 GeV and 500 GeV. The Higgs boson is produced in association with a fermion pair via the Higgsstrahlung proc

D. T. Son, M. A. Stephanov

QCD at finite isospin chemical potential mu_I is studied. This theory has no fermion sign problem and can be simulated on the lattice using present-day techniques. We solve this theory analytically in two limits: low mu_I where chiral perturbation theory is applicable, and asymptotically high mu_I where perturbative QCD is at work. At low isospin density the

A. Djouadi, Y. Mambrini

We investigate the decays of third generation scalar quarks in the Minimal Supersymmetric extension of the Standard Model, focusing on the three-body modes. We calculate the partial widths of the decays of heavier top and bottom squarks into the lighter ones and a fermion pair [through virtual vector boson, Higgs boson or gaugino exchanges] and the partial w

M. Anselmino, D. Boer, U. D'Alesio, F. Murgia

We study the fragmentation of a transversely polarized quark into a non collinear (k_T not= 0) spinless hadron and the fragmentation of an unpolarized quark into a non collinear transversely polarized spin 1/2 baryon. These nonperturbative properties are described by spin and k_T dependent fragmentation functions and are revealed in the observation of single

Kaoru Hagiwara

In this report I surveyed physics potential of the gamma-gamma option of a Linear e+e- Collider with the following questions in mind: What new discovery can be expected at a gamma-gamma collider in addition to what will be learned at its `parent' e+e- Linear Collider? By taking account of the hard energy spectrum and polarization of colliding photons, pr

K. Terasaki

Two-body decays of B mesons are studied by decomposing their amplitude into a sum of factorizable and non-factorizable ones. The former is estimated by using the naive factorization while the latter is calculated by using a hard pion (or kaon) approximation in the infinite momentum frame. It is seen that the non-factorizable contribution is small but not neg

Lay Nam Chang, Oleg Lebedev, Will Loinaz, Tatsu Takeuchi

We consider extensions of the Standard Model with an extra U(1) gauge boson which couples to B-(alpha L_e + beta L_mu + gamma L_tau) with alpha + beta + gamma = 3. We show that the extra gauge boson necessarily mixes with the Z leading to potentially significant corrections to the Z-f-fbar vertex. The constraints on the size of this correction imposed by the

Johannes Blümlein

We investigate the potential to measure the electro-weak couplings of scalar leptoquarks $Φ_s$ at TESLA for energies in the range of $\sqrt{s} \simeq 1 \TeV$ using the pair production process $e^+e^- \to Φ_s \barΦ_s$.

Junegone Chay, Chul Kim

We consider the exclusive decay $B\to J/ψK$ using the QCD-improved factorization method in the heavy quark limit. It is shown that the decay amplitude is factorizable in this limit and nonfactorizable contributions are calculable from first principles in perturbation theory. Also the spectator contributions at order $α_s$ are finite and suppressed in the hea

Uma Mahanta

In this paper we derive a quasi unitarity bound on the radion mass ($\mphi$) from the process $hh\to ϕϕ$. We find that at sufficiently high energies (i.e. when $ s\gg m_h^2, \mphi^2 $) the J=0 partial wave amplitude for the above process violates unitarity if $\mphi^2 > m_h^2+16 π\vphi^2 $. Combining this result with the unitarity bound $m_h^2<{16πv\vphi\ove

Stephen Sharpe, Noam Shoresh

We describe how one can use chiral perturbation theory to obtain results for physical quantities, such as quark masses, using partially quenched simulations.

Laurent Lellouch

I review this year&#39;s developments in the study of weak matrix elements of light hadrons on the lattice, with emphasis on K^0-\bar K^0 mixing and K -> pi pi decays.

M. A. Halasz

We consider a lattice-inspired random matrix model for the QCD chiral phase transition at finite chemical potential. Useful features of the usual RMM for QCD at finite chemical potential are reobtained, some being brought closer to their lattice equivalent. The simple physical requirement of a vanishing quark number density in the broken phase is fulfilled i

Leo Bellantoni

Rare decay results from KTeV are reviewed, emphasizing modes that in principle provide information about the CKM matrix. Our recent results in lepton flavor violating modes are also presented.

G. Vuagnin

The e+e- annihilation data recorded with the BABAR detector has been used to study B^0 decays to Ds^(*)+ and D^*-$ mesons. The production fraction of inclusive Ds^(*)+ and the corresponding momentum spectra have been determined. Exclusive decays B^0 --> D^*- Ds^(*)+ have been identified with a partial reconstruction technique and their branching ratios have

NuTeV Collaboration, B. T. Fleming

A new structure function analysis of CCFR deep inelastic nu-N and nubar-N scattering data is presented for previously unexplored kinematic regions down to Bjorken x=0.0045 and Q^2=0.3 GeV^2. Comparisons to charged lepton scattering data from NMC and E665 experiments are made and the behavior of the structure function F2_nu is studied in the limit Q^2 -> 0

NuTeV Collaboration, B. T. Fleming

A new structure function analysis of CCFR deep inelastic nu-N and nubar-N scattering data is presented for previously unexplored kinematic regions down to Bjorken x=0.0045 and Q^2=0.3 GeV^2. Comparisons to charged lepton scattering data from NMC and E665 experiments are made and the behavior of the structure function F2_nu is studied in the limit Q^2 -> 0.

H. Goenner, M. Leclerc

A special-relativistic scalar-vector theory of gravitation is presented which mimics an important class of solutions of Einstein&#39;s gravitational field equations. The theory includes solutions equivalent to Schwarzschild, Kerr, Reissner-Nordstroem, and Friedman metrics as well as to gravitational waves. In fact, all the empirical tests until now due to ge

Joan M. Centrella

The development of both ground- and space-based gravitational wave detectors provides new opportunities to observe the radiation from binaries containing neutron stars and black holes. Numerical simulations in 3-D are essential for calculating the coalescence waveforms, and comprise some of the most challenging problems in astrophysics today. This article br

Simonetta Frittelli, Thomas P. Kling, Ezra T. Newman

In a previous article concerning image distortion in non-perturbative gravitational lensing theory we described how to introduce shape and distortion parameters for small sources. We also showed how they could be expressed in terms of the scalar products of the geodesic deviation vectors of the source&#39;s pencil of rays in the past lightcone of an observer

Simonetta Frittelli, Thomas P. Kling, Ezra T. Newman

We introduce the idea of {\it shape parameters} to describe the shape of the pencil of rays connecting an observer with a source lying on his past lightcone. On the basis of these shape parameters, we discuss a setting of image distortion in a generic (exact) spacetime, in the form of three {\it distortion parameters}. The fundamental tool in our discussion

Lars Andersson

I discuss recent work (gr-qc/0001047) on non-oscillatory singularities in four dimensional space-times with scalar field or stiff fluid matter, in the context of the BKL proposal.

Hendrik Blockeel, Luc De Raedt, Nico Jacobs, Bart Demoen

When comparing inductive logic programming (ILP) and attribute-value learning techniques, there is a trade-off between expressive power and efficiency. Inductive logic programming techniques are typically more expressive but also less efficient. Therefore, the data sets handled by current inductive logic programming systems are small according to general sta

Ch. Helm, J. Keller, Ch. Preis, A. Sergeev

A microscopic theory for the coupling of intrinsic Josephson oscillations due to charge fluctuations on the quasi two-dimensional superconducting layers is presented. Thereby in close analogy to the normal state the effect of the scalar potential on the transport current is taken into account consistently. The dispersion of collective modes is derived and an

Jordan M. Gerton, Dmitry Strekalov, Ionut Prodan, Randall G. Hulet

The dynamical behavior of Bose-Einstein condensation (BEC) in a gas with attractive interactions is striking. Quantum theory predicts that BEC of a spatially homogeneous gas with attractive interactions is precluded by a conventional phase transition into either a liquid or solid. When confined to a trap, however, such a condensate can form provided that its

V. W. Scarola, Kwon Park, J. K. Jain

The scarcity of the fractional quantum Hall effect in higher Landau levels is a most intriguing fact when contrasted with its great abundance in the lowest Landau level. This paper shows that a suppression of the hard core repulsion in going from the lowest Landau level to higher Landau levels leads to a collapse of the energy of the neutral excitation, dest

V. W. Scarola, J. K. Jain

We construct a class of composite fermion states for bilayer electron systems in a strong transverse magnetic field, and determine quantitatively the phase diagram as a function of the layer separation, layer thickness, and electron density. We find, in general, that there are several transitions, and that the incompressible phases are separated by compressi

M. Mercedes Calbi, Flavio Toigo, Milton W. Cole

A study is presented of the effects of gas (especially H2) absorption within the interstitial channels of a bundle of carbon nanotubes. The ground state of the system is determined by minimizing the total energy, which includes the molecules&#39; interaction with the tubes, the inter-tube interaction, and the molecules&#39; mutual interaction (which is scree

C. J. Olson, C. Reichhardt, M. McCloskey, R. J. Zieve

With simulation and experiment we examine the effect of grain anisotropy on the angle of repose in a two-dimensional geometry. We find that the structure of the granular packing can be directly controlled by changing the aspect ratio of the grains, and that the specific type of order strongly affects the angle of repose and the resulting dynamics. The angle

L. S. Schulman

Using symmetric boundary conditions at separated times, I show analytically that both the time ordering of (macroscopic) causality and the direction of entropy increase follow from these boundary conditions. In particular, when the endpoints have low entropy, these arrows of time point away from the ends and toward the middle. Causality in this context means

Lorenzo Cornalba, Jean-Philippe Bouchaud, Marc Potters

We consider the problem of option pricing and hedging when stock returns are correlated in time. Within a quadratic-risk minimisation scheme, we obtain a general formula, valid for weakly correlated non-Gaussian processes. We show that for Gaussian price increments, the correlations are irrelevant, and the Black-Scholes formula holds with the volatility of t

Shu-Chiuan Chang, Robert Shrock

We present exact calculations of the partition function of the q-state Potts model for general q and temperature on strips of the square lattice of width L_y=3 vertices and arbitrary length L_x with periodic longitudinal boundary conditions, of the following types: (i) (FBC_y,PBC_x)= cyclic, (ii) (FBC_y,TPBC_x)= Möbius, (iii) (PBC_y,PBC_x)= toroidal, and (iv

C. S. Nelson, M. v. Zimmermann, J. P. Hill, Doon Gibbs

We report x-ray scattering studies of broad peaks located at a (0.5 0 0)/(0 0.5 0)-type wavevector in the paramagnetic insulating phases of La_{0.7}Ca_{0.3}MnO_{3} and Pr_{0.7}Ca_{0.3}MnO_{3}. We interpret the scattering in terms of correlated polarons and measure isotropic correlation lengths of 1-2 lattice constants in both samples. Based on the wavevector

M. C. Cross, Ron Lifshitz

The transmission coefficient for vibrational waves crossing an abrupt junction between two thin elastic plates of different widths is calculated. These calculations are relevant to ballistic phonon thermal transport at low temperatures in mesoscopic systems and the Q for vibrations in mesoscopic oscillators. Complete results are calculated in a simple scalar

J. Karadamoglou, N. Papanicolaou, X. Wang, X. Zotos

We present an accurate transfer matrix renormalization group calculation of the thermodynamics in a quantum spin-1 planar ferromagnetic chain. We also calculate the field dependence of the magnon gap and confirm the accuracy of the magnon dispersion derived earlier through an 1/n expansion. We are thus able to examine the validity of a number of previous cal

S. Bogner, T. Emig, T. Nattermann

The structural correlation functions of a weakly disordered Abrikosov lattice are calculated in a functional RG-expansion in $d=4-ε$ dimensions. It is shown, that in the asymptotic limit the Abrikosov lattice exhibits still quasi-long-range translational order described by a {\it nonuniversal} exponent $η_{\bf G}$ which depends on the ratio of the renormaliz

Philippe Jund, Remi Jullien, Ian Campbell

Stretched exponential relaxation ($\exp{-(t/τ)}^{β_K}$) is observed in a large variety of systems but has not been explained so far. Studying random walks on percolation clusters in curved spaces whose dimensions range from 2 to 7, we show that the relaxation is accurately a stretched exponential and is directly connected to the fractal nature of these clust

Paolo Grigolini, Riccardo Mannella, Luigi Palatella

We study a spatial diffusion process generated by velocity fluctuations of intermittent nature. We note that intermittence reduces the entropy production rate while enhancing the diffusion strength. We study a case of space-dependent intermittence and prove it to result in a deviation from uniform distribution. This macroscopic effect can be used to measure

Alain Barrat, Jorge Kurchan, Vittorio Loreto, Mauro Sellitto

We present numerical support for the hypothesis that macroscopic observables of dense granular media can be evaluated from averages over typical blocked configurations: we construct the corresponding measure for a class of finite-dimensional systems and compare its predictions for various observables with the outcome of the out of equilibrium dynamics at lar

J. Balogh, L. F. Kiss, A. Halbritter, I. Kézsmárki

Ag/Fe/Ag and Cr/Fe/Cr trilayers with a single $25 nm$ thick ferromagnetic layer exhibit giant magnetoresistance (GMR) type behavior. The resistance decreases for parallel and transversal magnetic field alignements with a Langevin-type magnetic field dependence up to B=12 T. The phenomenon is explained by a granular interface structure. Results on Fe/Ag multi

Koh Wada, Shun-ichi Yoshida, Norihiro Ihara

The time dependent cluster approximation called the path probability method (PPM) is applied to a pseudo-spin Ising Hamiltonian of the Slater-Takagi model for KH2PO4-type hydrogen-bonded ferroelectrics in order to calculate the homogeneous dynamical susceptibility above and below the ferroelectric transition temperature. Above the transition temperature all

Rene Messina, Michele Soucail, Ladislas Kubin

Abnormal grain growth in the presence of second phase particles is investigated with the help of a two-dimensional Monte Carlo simulation. An aggregate of equiaxed grains is considered with constant grain boundary energy and mobility. The only driving force accounted for stems from the grain boundary curvature. The process of abnormal grain growth is investi

S. Drozdz, F. Gruemmer, F. Ruf, J. Speth

Effects connected with the world globalization affect also the financial markets. On a way towards quantifying the related characteristics we study the financial empirical correlation matrix of the 60 companies which both the Deutsche Aktienindex (DAX) and the Dow Jones (DJ) industrial average comprised during the years 1990-1999. The time-dependence of the

Rong Lu, Hui Pan, Jia-Lin Zhu, Bing-Lin Gu

The quantum interference effects induced by the topological phase are studied analytically in biaxial antiferromagnets with an external magnetic field at an arbitrarily angle. This study provides a nontrivial generalization of the Kramers degeneracy for equivalent double-well system to coherently spin tunneling at ground states as well as low-lying excited s

Z. Haba, H. Kleinert

We set up a forward--backward path integral for a point particle in a bath of photons to derive a master equation for the density matrix which describes electromagnetic dissipation and decoherence. As an application, we recalculate the Weisskopf-Wigner formula for the natural line width of an atomic state at zero temperature and find, in addition, the temper

R. Hlubina

We solve the Boltzmann equation for electrons moving in a two-dimensional plane of square symmetry in the presence of a transverse magnetic field. We assume that there are two sources of scattering: a large momentum-independent scattering on a collective mode of the electron system, and a smaller momentum-dependent forward scattering on impurities. We show t

Raffaele Cafiero, Stefan Luding

We propose a mean field (MF) theory for a homogeneously driven granular gas of inelastic particles with Coulomb friction. The model contains three parameters, a normal restitution coefficient $r_n$, a maximum tangential restitution coefficient $r_t^m$, and a Coulomb friction coefficient $μ$. The parameters can be tuned to explore a wide range of physical sit

S. Grollau, M. L. Rosinberg, G. Tarjus

We study the phase diagram of the ferromagnetic $q$-state Potts model on the various three-dimensional lattices for integer and non-integer values of $q>1$. Our approach is based on a thermodynamically self-consistent Ornstein-Zernike approximation for the two-point correlation functions. We calculate the transition temperatures and, when the transition is f

Tomasz Krzyszton

The influence of the antiferromagnetic order on the superconductor in the mixed state results in creation of spin-flop domains along the cores of the vortex lines. It is shown that this phenomenon makes possible crossover from quantum creep regime to thermal one, and vice versa, at constant temperature. To do this one needs to simply change the intensity or

Zhen Ye, Pi-Gang Luan

Radiation from acoustic sources located inside randomly-layered structures is studied using the transfer matrix method. It is shown that in contrast to the periodically layered cases where the radiation can be either enhanced or inhibited depending on the frequency, and the characteristics and the material composition of the structures, in the random structu

A. Saguia, B. Boechat, M. A. Continentino, O. F. de Alcantara Bonfim

We investigate the application of a perturbative renormalization group (RG) method to random antiferromagnetic Heisenberg chains with arbitrary spin size. At zero temperature we observe that initial arbitrary probability distributions develop a singularity at J=0, for all values of spin S. When the RG method is extended to finite temperatures, without any ad

N. Harrison, N. Biskup, J. S. Brooks, L. Balicas

We report the results of a detailed study of the field orientation-dependence of the de Haas-van Alphen waveform in $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$. By considering the field orientation-dependence of the sign and phase of the fundamental $α$ frequency, at fields both well above and below the kink transition field, it is found that a single value for the produ

Gary Hinshaw

We present an overview of the upcoming Microwave Anisotropy Probe (MAP) mission, with an emphasis on those aspects of the mission that simplify the data analysis. The method used to make sky maps from the differential temperature data is reviewed and we present some of the noise properties expected from these maps. An overview of the method we plan to use to

Sandro Mereghetti

We present a BeppoSAX observation of the X-ray source AX J0851.9-4617.4 that has been proposed as the neutron star associated to the shell like-supernova remnant RX J0852.0-4622. The image at E>5 keV shows the presence of a new source, SAX J0852.0-4615, not resolved from AX J0851.9-4617.4 in previous observations. The improved positional accuracy obtained fo

G. Bertone, G. Sigl, J. Silk

A massive black hole is present at the centre of our galaxy and inevitably accretes dark matter particles, creating a region of very high particle density. The annihilation rate is enhanced with a large number of e+e- pairs produced either directly or by successive decays of mesons. We evaluate the synchrotron emission (and self-absorption) associated with t

K. D. Kuntz, S. L. Snowden, R. F. Mushotzky

Three observational constraints can be placed on a warm-hot intergalactic medium (WHIM) using \rosat PSPC pointed and survey data, the emission strength, the energy spectrum, and the fluctuation spectrum. The upper limit to the emission strength of the WHIM is 7.5 +/- 1.0 keV s^-1 cm^-2 sr^-1 keV^-1 in the 3/4 keV band, an unknown portion of which value may

M. H. Montgomery, T. S. Metcalfe, D. E. Winget

We consider envelopes of DB white dwarfs which are not composed of pure 4-He, but rather a mixture of 3-He and 4-He. Given this assumption, the same diffusive processes which produce a relatively pure H layer overlying a He layer in the DA&#39;s should work to produce a 3-He layer overlying a 4-He layer in the DB&#39;s. We examine the relevant timescales for

Jean Eilek

We do not fully understand the dynamics and evolution of a radio galaxy. Models of classical double (Type II) sources are in a reasonable state, but these objects are rare. Non-type II sources (generically called Type I) are far more common, but much less well understood. In this paper I use the data to suggest possible new models for Type I sources, and dis

J. Eilek, P. Hardee, T. Markovic, M. Ledlow

The tailed radio galaxies that have been called ``Type I&#39;&#39; are not a uniform set. To study their dynamics, we have used the Ledlow-Owen data set, which provides a new sample of 250 radio galaxies in nearby Abell clusters. These sources divide into two clear categories based on their radio morphology. Type A sources (``straight&#39;&#39;) contain near

A. C. Fabian, J. S. Sanders, S. Ettori, G. B. Taylor

We report the discovery of a 40 arcsec long X-ray filament in the core of the cluster of galaxies A1795. The feature coincides with an Halpha+NII filament found by Cowie et al in the early 1980s and resolved into at least 2 U-band filaments by McNamara et al in the mid 1990s. The (emission-weighted) temperature of the X-ray emitting gas along the filament is

C. Bruens, J. Kerp, L. Staveley-Smith

The LMC, SMC, and the Milky Way are a spectacular set of interacting galaxies. The prominent tidal arms which protrude from the Magellanic Clouds extend for tens of kiloparsecs and cover a large part of the southern sky. These arms, and the Magellanic Clouds themselves, are therefore a highly suitable subject for the detailed investigation of an interacting

Hannu Kurki-Suonio, Elina Sihvola

The recent Boomerang and MAXIMA data on the cosmic microwave background suggest a large value for the baryonic matter density of the universe, omega_b = 0.03. This density is larger than allowed by standard big bang nucleosynthesis theory and observations on the abundances of the light elements. We explore here the possibility of accommodating this high dens

A. A. Zdziarski, P. Grandi

We study a broad-band X-ray observation by BeppoSAX of the broad-line radio galaxy 3C 120. The primary X-ray continuum is well described by a power law with the photon index of Gamma=1.85+-0.05 and a high-energy break or a cutoff. The obtained e-folding energy of about100-300 keV corresponds to kT of about 50 keV in thermal-Compton models. A soft X-ray exces

David A. Smith, Ioannis Georgantopoulos, Robert S. Warwick

We present RXTE monitoring observations of the Seyfert 2 galaxy Mrk 348 spanning a 6 month period. The time-averaged spectrum in the 3-20 keV band shows many features characteristic of a Compton-thin Seyfert 2 galaxy, namely a hard underlying power-law continuum (photon index = 1.8) with heavy soft X-ray absorption (N_h ~ 10^23 cm^-2) plus measureable iron l

S. V. Bogovalov

Violation of the axial synnetry of a magnetic field essentially modifies the physics of the plasma outflow in the magnetosphere of rotating objects. In comparison to the axisymmetric outflow, two new affects appear: more efficient magnetocentrifugal acceleration of the plasma along particular field lines and generation of MHD waves. Here, we use an ideal MHD

Jayaram N Chengalur, Nissim Kanekar

We present Giant Metrewave Radio Telescope HI 21cm absorption observations, of candidate and confirmed damped Lyman-$α$ systems (DLAS). The derived spin temperatures (T_s) are in all cases $\sim 1000$ K or higher. We have also collated from the literature a list of DLAS for which 21cm observations exist, and discuss their implications for the nature of the a

Kaiki Taro Inoue

We have investigated the cosmic microwave background (CMB) anisotropy in closed multiply connected universes (flat and hyperbolic) with low matter density. We show that the COBE constraints on these low matter density models with non-trivial topology are less stringent since a large amount of CMB anisotropy on large angular scales can be produced due to the

Hyesung Kang, T. W. Jones, R. J. LeVeque, K. M. Shyue

We have developed a novel computer code designed to follow the evolution of cosmic-ray modified shocks, including the full momentum dependence of the particles for a realistic diffusion coefficient model. In this form the problem is technically very difficult, because one needs to cover a wide range of diffusive scales, beginning with those slightly larger t

A. P. Jacob, T. R. Bedding, J. G. Robertson, J. R. Barton

We present visibility measurements of the nearby Mira-like star R Doradus taken over a wide range of wavelengths (650-990 nm). The observations were made using MAPPIT (Masked APerture-Plane Interference Telescope), an interferometer operating at the 3.9-m Anglo-Australian Telescope. We used a slit to mask the telescope aperture and prism to disperse the inte

Timothy R. Bedding

Interferometric techniques are at the forefront of modern astronomical instrumentation. A new generation of instruments are either operating or nearing completion, including arrays of small telescopes as well as the ``big guns&#39;&#39; (VLTI and Keck). A number of space interferometers for the detection of extra-solar planets are also being planned. I revie

Emi Miyata, Kouji Ohta, Kenichi Torii, Toshiaki Takeshima

AX J2049.6+2939 is a compact X-ray source in the vicinity of the southern blow-up region of the Cygnus Loop supernova remnant (Miyata et al. 1998a). This source was the brightest X-ray source inside the Cygnus Loop observed during the ASCA survey project. The X-ray spectrum was well fitted by a power-law function with a photon index of $-2.1 \pm 0.1$. Short-

L. C. Garcia de Andrade

A rotating universe represented by the Gödel metric in spacetimes with Cartan torsion is investigated where the Cosmic Microwave Background Radiation (CMBR) is computed from the Gödel rotation of the universe and the spin density of the spinning fluid in Einstein-Cartan gravity.The autoparallel equation in Riemann-Cartan spacetime is shown to lead to the evo

Qimiao Si, Silvio Rabello, Kevin Ingersent, Lleweilun Smith

When a metal undergoes a continuous quantum phase transition, non-Fermi liquid behaviour arises near the critical point. It is standard to assume that all low-energy degrees of freedom induced by quantum criticality are spatially extended, corresponding to long-wavelength fluctuations of the order parameter. However, this picture has been contradicted by rec

J. W. Moffat

A calculation of the one loop gravitational self-energy graph in non-anticommutative quantum gravity reveals that graviton loops are damped by internal momentum dependent factors in the modified propagator and the vertex functions. The non-anticommutative quantum gravity perturbation theory is finite for matter-free gravity and for matter interactions.

Kurusch Ebrahimi-Fard

In this note we comment on part of a recent article by B. Schroer and H.-W. Wiesbrock. Therein they calculate some new modular structure for the U(1)-current-algebra (Weyl-algebra). We point out that their findings are true in a more general setting. The split-property allows an extension to doubly-localized algebras.

Christian W. Bauer, Sean Fleming, Dan Pirjol, Iain W. Stewart

We construct the Lagrangian for an effective theory of highly energetic quarks with energy Q, interacting with collinear and soft gluons. This theory has two low energy scales, the transverse momentum of the collinear particles, p_perp, and the scale p_perp^2/Q. The heavy to light currents are matched onto operators in the effective theory at one-loop and th

Akakii Melikidze

I consider the problem of vortex tunneling in a two-dimensional superconductor. The vortex dynamics is governed by the Magnus force and the Ohmic friction force. Under-barrier motion in the vicinity of the saddle point of the pinning potential leads to a model with quadratic Hamiltonian which can be analytically diagonalized. I find the dependence of the tun

Jonathan L. Rosner

The role of B decays in the study of CP violation is reviewed. We treat the interactions and spectroscopy of the $b$ quark and then introduce CP violation in $B$ meson decays, including time-dependences, decays to CP eigenstates and non-eigenstates, and flavor tagging. Additional topics include studies of strange $B$&#39;s, decays to pairs of light pseudosca

Xuelei Chen, Robert J. Scherrer, Gary Steigman

In extended quintessence models, a scalar field which couples to the curvature scalar R provides most of the energy density of the universe. We point out that such models can also lead naturally to a decrease in the primordial abundance of helium-4, relieving the tension which currently exists between the primordial helium-4 abundance inferred from observati

Daniel Boyanovsky, H. J. de Vega

In normal degenerate quark matter, the exchange of dynamically screened transverse gluons introduces infrared divergences in the quark self-energies that lead to the breakdown of the Fermi liquid description. If the core of neutron stars are composed of quark matter with a normal component, cooling by direct quark Urca processes may be modified by non-Fermi

M. Atiyah, J. Maldacena, C. Vafa

We show how a recently proposed large $N$ duality in the context of type IIA strings with ${\cal N}=1$ supersymmetry in 4 dimensions can be derived from purely geometric considerations by embedding type IIA strings in M-theory. The phase structure of M-theory on $G_2$ holonomy manifolds and an $S^3$ flop are the key ingredients in this derivation.

D. H. Santamore, M. C. Cross

We explain the reduction of the thermal conductance below the predicted universal value observed by Schwab et al. in terms of the scattering of thermal phonons off surface roughness using a scalar model for the elastic waves. Our analysis shows that the thermal conductance depends on two roughness parameters: the roughness amplitude $δ$ and the correlation l

Andrey Neronov, Ivo Sachs

In this note we reconsider linearised metric perturbations in the one-brane Randall-Sundrum Model. We present a simple formalism to describe metric perturbations caused by matter perturbations on the brane and remedy some misconceptions concerning the constraints imposed on the metric and matter perturbations by the presence of the brane.

N. Armesto, C. A. Salgado

We propose a new criterium for saturation of the density of partons both in nucleons and nuclei. It is applicable to any multiple scattering model which would be used to compute the number of strings exchanged in $ep$ and $eA$ collisions. The criterium is based on percolation of strings, and the onset of percolation is estimated from expectations coming from

G. A. Ummarino, R. S. Gonnelli, D. Daghero

We theoretically investigate the effect of various symmetries of the superconducting order parameter Delta(omega) on the normalized tunneling conductance of SIN junctions by directly solving the real-axis Eliashberg equations (EEs) for a half-filled infinite band, with the simplifying assumption mu*=0. We analyze six different symmetries of the order paramet

Jose M. Isidro

Expanded version of the author's contribution to the Concise Encyclopaedia of Supersymmetry, eds. J. Bagger, S. Duplij and W. Siegel

A. A Bytsenko, A. E. Goncalves, S. Zerbini

The effective potentials for massless scalar and vector quantum field theories on D dimensional manifolds with p compact noncommutative extra dimensions are evaluated by means of dimensional regularization implemented by zeta function techniques. It is found that the zeta function associated with the one-loop operator may not be regular at the origin. Thus,

Ion V. Vancea

In this note we analyse the dynamical potential of a system of four $Dp$-branes at arbitrary angles. The equilibrium configurations for various values of the relative angles and distances among branes are discussed. The known configurations of parallel branes and brane-antibranes are obtained at extrema of the dynamical potential.

NA36 Collaboration, E. Andersen

A high statistics study of the negative multiplicity distribution from S-Pb collisions at 200 GeV/c per nucleon is presented. The NA36 TPC was used to detect charged particles; corrections are based upon the maximum entropy method.

B. L. Ioffe, A. G. Oganesian

The method for calculation of valence quark distributions at intermediate $x$ is presented. The imaginary part of the virtual photon forward scattering amplitude on the quark current with meson quantum number is considered. Initial and final virtualities $p^2_1$ and $p^2_2$ of the currents are assumed to be large, negative and different, $p^2_1 \not= p^2_2$.

Frank Verstraete, Koenraad Audenaert, Tijl De Bie, Bart De Moor

We consider mixed states of two qubits and show under which global unitary operations their entanglement is maximized. This leads to a class of states that is a generalization of the Bell states. Three measures of entanglement are considered: entanglement of formation, negativity and relative entropy of entanglement. Surprisingly all states that maximize one

R. N. Faustov, A. P. Martynenko

We have formulated the quasipotential method for the calculation of the relativistic and radiative corrections to the magnetic moment of the two-particle bound state in the case of particles with arbitrary spin. It is shown that the g-factors of bound particles contain $O(α^2)$ terms depending on the particle spin. Numerical values for the g-factors of the e

Falk Bruckmann

We investigate the relation between instantons and monopoles in the Laplacian Abelian Gauge using analytical methods in the continuum. Our starting point is the fact that the &#39;t Hooft instanton with its high symmetry leads to a pointlike defect with Hopf invariant one. In order to generalise this result we partly break the symmetry by a local perturbatio

F. Ritz, H. Arenhoevel

Coherent $η$-meson photoproduction on the deuteron has been studied, where the emphasis is on the relative importance of two-body contributions from hadronic rescattering and electromagnetic meson exchange currents besides the impulse approximation. For the elementary photoproduction amplitude a coupled resonance model developed by Bennhold and Tanabe has be

Nick Dorey, Timothy J. Hollowood, Valentin V. Khoze

The D-instanton partition function is a fascinating quantity because in the presence of N D3-branes, and in a certain decoupling limit, it reduces to the functional integral of N=4 U(N) supersymmetric gauge theory for multi-instanton solutions. We study this quantity as a function of non-commutativity in the D3-brane theory, VEVs corresponding to separating

K. Abe

We report a determination of the B0d - B0d-bar mixing parameter Delta-m_d based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 /fb data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expr

Yu. P. Krasny, N. P. Kovalenko, U. Krey, L. Jacak

In the usual Fock-and Darwin-formalism with parabolic potential characterized by the confining energy $\eps_o := \hbarω_o= 3.37$ meV, but including explicitly also the Zeeman coupling between spin and magnetic field, we study the combined orbital and spin magnetic properties of quantum dots in a two-dimensional electron gas with parameters for GaAs, for N =1