January 1997 arXiv papers — page 5

Yuichiro Kiyo, Jiro Kodaira, Hiroshi Tochimura

We numerically analyse the evolution of the flavor non-singlet $g_{1}$ structure function taking into account the all-order resummation of $α_{s} ln^{2}x$ terms which is expected to have much stronger effects than the DGLAP evolution in the small x region. We include a part of the next-to-leading logarithmic corrections coming from the resummed ``coefficient

S. Loh, C. Greiner, U. Mosel, M. H. Thoma

We present two novel dynamical features of flux tubes in the Friedberg-Lee model. First the fusion of two (anti-)parallel flux tubes, where we extract a string-string interaction potential which has a qualitative similarity to the nucleon-nucleon potential in the Friedberg-Lee model obtained by Koepf et al. Furthermore we show the dynamical breakup of flux t

Hisakazu Minakata, Yoriaki Shimada

We define the ratio R = (No. of observed electron events)/ (No. of expected muon events - No. of observed muon events) as a measure for relative importance of $ν_μ\to ν_e$ and $ν_μ\to ν_τ$ oscillations which will be measurable in coming long-baseline neutrino experiments. We then argue that if neutrino oscillation is observed with 0.02 < R < 0.87 it implies

Jeffrey D. Richman

I review new results on particles containing a charm or bottom quark, focusing on measurements that give insight into the dynamics of the decay process. Leptonic and semileptonic decays are the simplest modes, and they provide detailed tests of theoretical predictions based on methods such as lattice QCD, heavy quark effective theory, and QCD sum rules. Alth

Frank Gronwald, Friedrich W. Hehl

The notions of stress and hyperstress are anchored in 3-dimensional continuum mechanics. Within the framework of the 4-dimensional spacetime continuum, stress and hyperstress translate into the energy-momentum and the hypermomentum current, respectively. These currents describe the inertial properties of classical matter fields in relativistic field theory.

S. Brian Edgar, Garry Ludwig

Held has proposed an integration procedure within the GHP formalism built around four real, functionally independent, zero-weighted scalars. He suggests that such a procedure would be particularly simple for the `optimal situation&#39;, when the formalism directly supplies the full quota of four scalars of this type; a spacetime without any Killing vectors w

Erik Christensen, Allan M. Sinclair

For a von Neumann algebra M on a Hilbert space, A. Connes has constructed a module S and a derivation of M into S, such that M is approximately finite dimensional if and only if that derivation is inner. The paper contains a generalization of this result to the situation with a 2-cocycle instead. The cocycle is the obvious generalization, and the module is c

Siye Wu, Weiping Zhang

We prove the equivariant holomorphic Morse inequalities for a holomorphic torus action on a holomorphic vector bundle over a compact Kahler manifold when the fixed-point set is not necessarily discrete. Such inequalities bound the twisted Dolbeault cohomologies of the Kahler manifold in terms of those of the fixed-point set. We apply the inequalities to obta

A. D. Mirlin, P. Woelfle

We consider the conductivity tensor for composite fermions in a close to half-filled Landau band in the temperature regime where the scattering off the potential and the trapped gauge field of random impurities dominates. The Boltzmann equation approach is employed to calculate the quasiclassical transport properties at finite effective magnetic field, wavev

M. Stebelski, M. Szopa, E. Zipper

The persistent currents driven by the pure Aharonov-Bohm type magnetic field in mesoscopic normal metal or semiconducting cylinders are studied. A two-dimensional (2D) Fermi surfaces are characterized by four parameters. Several conditions for the coherence and enhancement of currents are discussed. These results are then generalized to a three-dimensional (

Jacques Boutet de Monvel, Olivier C. Martin

Consider the length $L_{MM}^E$ of the minimum matching of N points in d-dimensional Euclidean space. Using numerical simulations and the finite size scaling law $< L_{MM}^E > = β_{MM}^E(d) N^{1-1/d}(1+A/N+... )$, we obtain precise estimates of $β_{MM}^E(d)$ for $2 \le d \le 10$. We then consider the approximation where distance correlations are neglected. Th

Bhargavi Srinivasan, S. Ramasesha

We have studied polyacene within the Hubbard model to explore the effect of electron correlations on the Peierls&#39; instability in a system marginally away from one-dimension. We employ the projector quantum Monte Carlo method to obtain ground state estimates of the energy and various correlation functions. We find strong similarities between polyacene and

I. N. Reid, J. E. Gizis, J. G. Cohen, M. A. Pahre

We use broadband photometry and low-resolution spectra of a complete sample of late-K and M dwarfs brighter than I=22 in three fields at high galactic latitude to study issues relating to galactic structure and large scale abundance gradients in the Galaxy. The observed starcounts in each field are a good match to the predictions of models based on deep star

Marek J. Kukula, James S. Dunlop, David H. Hughes, Geoff Taylor

We present the results of two complementary ground-based programmes to determine the host galaxy properties of radio-quiet and radio-loud quasars and to compare them with those of radio galaxies. Both infrared images and optical off-nuclear spectra were obtained and we discuss the various strategies used to separate the quasar-related emission from that of t

K. M. Gorski

The COBE satellite has provided the only comprehensive multi-frequency full-sky observations of the microwave sky available today. Assessment of the observations requires a detailed likelihood analysis to extract the maximum amount of information present in the noisy data. I present a specific method for estimating the CMB anisotropy power spectrum independe

R. P. Fender, R. E. Spencer, S. J. Newell, A. K. Tzioumis

We present radio observations of the black hole candidate X-ray binary GX 339-4 with the Australia Telescope compact array. Mapping of the highest resolution 3.5 cm data reveals a jet-like extension, which if confirmed would be the first detection of a radio jet from a persistent black-hole candidate system. No evidence is found for associated structures suc

Shin Mineshige, Masayuki Umemura

A self-similar solution for time evolution of isothermal, self-gravitating viscous disks is found under the condition that $α&#39; \equiv α(H/r)$ is constant in space (where $α$ is the viscosity parameter and $H/r$ is the ratio of a half-thickness to radius of the disk). This solution describes a homologous collapse of a disk via self-gravity and viscosity.

A. A. Tseytlin

We show that the part of the tree-level open string effective action for the non-abelian vector field which depends on the field strength but not on its covariant derivatives, is given by the symmetrised trace of the direct non-abelian generalisation of the Born-Infeld invariant. We discuss applications to D-brane dynamics.

Uwe Müller

A basis of Lorentz and gauge-invariant monomials in non--Abelian gauge theories with matter is described, applicable for the inverse mass expansion of effective actions. An algorithm to convert an arbitrarily given invariant expression into a linear combination of the basis elements is presented. The linear independence of the basis invariants is proven.

Gabor Takacs

An exact S-matrix is conjectured for the imaginary coupled d_4(3) affine Toda field theory, using the U_q(g_2(1)) symmetry. It is shown that this S-matrix is consistent with the results for the case of real coupling using the breather-particle correspondence. For q a root of unity it is argued that the theory can be restricted to yield Phi(11|14) perturbatio

A. A. Pankov, N. Paver, C. Verzegnassi

We show that the availability of longitudinally polarized electron beams at a 500 GeV Linear Collider would allow, from an analysis of the reaction e^+e^-\to W^+W^-, to set stringent bounds on the couplings of a Z&#39; of the most general type. In addition, to some extent, it would be possible to disentangle observable effects of the Z&#39; from analogous on

Dorje C. Brody, Lane P. Hughston

A statistical model M is a family of probability distributions, characterised by a set of continuous parameters known as the parameter space. This possesses natural geometrical properties induced by the embedding of the family of probability distributions into the Hilbert space H. By consideration of the square-root density function we can regard M as a subm

Mikhail Braun, Gian Paolo Vacca

An analysis of minijet production from the hard pomeron with a running coupling constant is performed. Two supercritical pomerons found in the numerical study are taken into account. The calculated inclusive jet production rate is finite at small $k_{\bot}$ and behaves like $1/k^{-4}_{\bot}$ at high $k_{\bot}$ modulo factors coming from logarithmic terms. Th

M. H. Thoma, C. T. Traxler

The resummation technique of Braaten and Pisarski is used for a complete calculation of the $α^2 α_s$-contribution to the production rate of dileptons with energy E >> T and invariant mass M <~ T from a quark-gluon plasma. In particular the cancellation of the infrared singularity by medium effects is discussed in detail.

Supriya Kar

We study the D-brane solutions to type IIB superstring in ten dimensions and find interpretation in terms of compactification of a twelve dimensional three-brane of (a specific) F-theory on a torus $T^2$. In this frame-work, there also exist a two-brane which may be argued to be equivalent to the three-brane by utilizing the electric-magnetic duality in elev

H. Ebeling, A. C. Edge, A. C. Fabian, S. W. Allen

We present and discuss the X-ray luminosity function (XLF) of the ROSAT Brightest Cluster sample (BCS), an X-ray flux limited sample of clusters of galaxies in the northern hemisphere compiled from ROSAT All-Sky Survey data. The BCS allows the local cluster XLF to be determined with unprecedented accuracy over almost three decades in X-ray luminosity and pro

Martin Gremm, Anton Kapustin

We analyze the relativistic corrections to annihilation rates of S-wave quarkonia within the framework of NRQCD. We show that order v^2 corrections can be expressed in terms of the heavy quark pole mass and the quarkonium mass. The ratio of hadronic to radiative annihilation rates for eta_b and eta_c can therefore be predicted accurately. The contributions o

Jin Young Kim, H. W. Lee, Y. S. Myung

We study the Giddings-Strominger wormholes in string theories. We found negative modes among O(4)-symmetric fluctuations about the non-singular wormhole background. Hence the stringy wormhole contribution to the euclidean functional integral is purely imaginary. This means that the stringy wormhole is a bounce (not an instanton) and describes the nucleation

L. Schulman, D. Mozyrsky

The extent to which a given wave function, $ψ$, is entangled is measured by minimizing the norm of $ψ$ minus all possible unentangled functions. This measure is given by the largest eigenvalue of $ψ^\dagger ψ$, considered as an operator. The definition is basis independent.

R. Derka, V. Buzek, G. Adam, P. L. Knight

We derive an expression for a density operator estimated via Bayesian quantum inference in the limit of an infinite number of measurements. This expression is derived under the assumption that the reconstructed system is in a pure state. In this case the estimation corresponds to an averaging over a generalized microcanonical ensemble of pure states satisfyi

V. Buzek, V. Vedral, M. B. Plenio, P. L. Knight

We show that inseparability of quantum states can be partially broadcasted (copied, cloned) with the help of local operations, i.e. distant parties sharing an entangled pair of spin 1/2 states can generate two pairs of partially nonlocally entangled states using only local operations. This procedure can be viewed as an inversion of quantum purification proce

Millard H. Alexander, Andrew Walton, Moonbong Yang, Xin Yang

We report the investigation of the 3s <- 2p transition in the BAr2 cluster. In a supersonic expansion of B atoms entrained in Ar, at high beam source backing pressures we observe several features in the fluorescence excitation spectrum which cannot be assigned to the BAr diatom. Using BAr(X, B) potential energy curves which reproduce our experimental observa

Todd Kapitula

The stability of the bright solitary wave solution to the perturbed cubic-quintic Schroedinger equation is considered. It is shown that in a certain region of parameter space these solutions are unstable, with the instability being manifested as a small positive eigenvalue. Furthermore, it is shown that in the complimentary region of parameter space there ar

Aric Hagberg, Ehud Meron, I. Rubinstein, B. Zaltzman

Near a parity breaking front bifurcation, small perturbations may reverse the propagation direction of fronts. Often this results in nonsteady asymptotic motion such as breathing and domain breakup. Exploiting the time scale differences of an activator-inhibitor model and the proximity to the front bifurcation, we derive equations of motion for planar and ci

S. M. H. Wong

We consider the evolution of a parton plasma created in Au+Au collisions at LHC and at RHIC energies. Using Boltzmann equation, relaxation time approximation and perturbative QCD, we show the physics of both thermal and chemical equilibration in a transparent manner. In particular, we show inelastic processes are, contrary to common assumption, more importan

Robin Pemantle

Lower and upper estimates are given for the probability that the epsilon-enlargement of planar Brownian motion to time 1 (the epsilon sausage) contains a unit line segment. The estimates imply that Brownian motion to time 1 itself contains no line segment.

Itai Benjamini, Robin Pemantle, Yuval Peres

We show that oriented percolation occurs whenever a condition is satisfied called &#34;exponential intersection tails&#34;. This condition says that a measure on paths exists for which the probability of two independent paths intersecting in more than k sites is exponentially small in k.

Olle Haggstrom, Robin Pemantle

We generalize Richardson&#39;s model by starting with two sites of different colors and giving each new site the color of the site that spawned it. We show that co-existence is possible.

O. Adelman, Krzysztof Burdzy, Robin Pemantle

Any fixed cylinder is hit almost surely by a 3-dimensional Brownian motion, but is there a random cylinder that is in the complement? We answer this for cylinders, and then replacing a cylinder with a more general set.

Robin Pemantle, Stanislav Volkov

Vertex-reinforced random walk is defined in Pemantle&#39;s (1988) thesis; it is a random walk that is biased to visit sites it has already visited a lot. We show that this reinforcement scheme, in contrast to the scheme of edge-reinforcement, causes random walk on a line to get trapped in a finite set.

Robin Pemantle, Stanislav Volkov

A general criterion is given for when a Markov chain trapped with probability p(x) in state x will be almost surely trapped. The quenched (state x is a trap forever with probability p(x)) and annealed (state x traps with probability p(x) on each visit) problems are shown to be equivalent.

Lincoln Chayes, Robin Pemantle, Yuval Peres

We show that fractal (or &#34;Mandelbrot&#34;) percolation in two dimensions produces a set containing no directed paths, when the set produced has zero area. This improves a similar result by the first author in the case of constant retention probabilities to the case of retention probabilities approaching 1.

Niels Jakob Laustsen

It is proved that, for each pair (m,n) of non-negative integers, there is a Banach space X for which the group K_0(B(X)) is isomorphic to m copies of the integers and the group K_1(B(X)) is isomorphic to n copies of the integers. Along the way we compute the K-groups of all closed ideals of operators contained in the ideal of strictly singular operators, and

Fermin Aldabe, Arne L. Larsen

Explicit open single and multi-membrane solutions of the low energy limit of M-theory on the orbifold $R^{10}\times S^1/Z_2$ are presented. This low energy action is described by an 11-dimensional supergravity action coupled to two $E_8$ super Yang-Mills fields, which propagate only on the 10-dimensional boundaries of the target space. The membrane solutions

A. Marshakov, A. Mironov, A. Morozov

We consider 4d and 5d N=2 supersymmetric theories and demonstrate that in general their Seiberg-Witten prepotentials satisfy the Witten-Dijkgraaf-Verlinde-Verlinde (WDVV) equations. General proof for the Yang-Mills models (with matter in the first fundamental representation) makes use of the hyperelliptic curves and underlying integrable systems. A wide clas

Marco Laucelli Meana, M. A. R. Osorio, Jesús Puente Peñalba

We study the microcanonical density of states and the thermal properties of a bosonic string gas starting from a calculation of the Helmholtz free energy in the S-representation. By adding more and more strings to the single string system, we induce that, for infinite volume, there is no negative specific heat region but a transition at a finite value of the

Jose&#39; P. S. Lemos

Black holes in several dimensions and in several theories are studied and discussed. The theories are, general relativity, Kaluza-Klein, Brans-Dicke, Lovelock gravity and string theory.

H. M. Chan, S. T. Tsou

Possible physical consequences of a recently discovered nonabelian dual symmetry are explored in the standard model. It is found that both Higgs fields and fermion generations can be assigned a natural place in the dual framework, with Higgs fields appearing as frames (or `N-beins&#39;) in internal symmetry space, and generations appearing as spontaneously b

J. Froehlich, J. Hoppe

We recall a formulation of super-membrane theory in terms of certain matrix models. These models are known to have a mass spectrum given by the positive half-axis. We show that, for the simplest such matrix model, a normalizable zero-mass ground state does not exist.

Jnanadeva Maharana, Sudipta Mukherji, Sudhakar Panda

We study the classical equations of motion and the corresponding Wheeler-De Witt equation for tree level string effective action with the dilaton and axion. The graceful exit problem in certain cases is then analysed.

D. Boyanovsky, H. J. de Vega, R. Holman, S. Prem Kumar

We study photoproduction during the non-equilibrium stages of the formation of chiral condensates within the ``quench&#39;&#39; scenario of the chiral phase transition. The dynamics is modeled with a gauged linear sigma model. A novel quantum kinetic approach to the description of photoproduction far off equilibrium is developed. We find that non-equilibrium

Marek Jezabek, Leszek Motyka

Analytic formulae are given for order alpha_s perturbative QCD corrections to the double differential distribution of the tau lepton energy and the invariant mass of the tau + antineutrino system in semileptonic decays of the bottom quark. The corresponding distribution for B meson decays are obtained by combining these results and the nonperturbative QCD co

Werner Bernreuther

A brief overview is given on the status and prospects of searches for CP nonconservation effects in weak decays of strange, charmed, and beauty hadrons, on the search for permanent electric dipole moments of particles, and on present and future high energy CP tests at colliders.

S. P. Klevansky, P. Rehberg, A. Ogura, J. H&#34;ufner

Transport theory for the Nambu--Jona-Lasinio (NJL) model is examined. The collision term is investigated in a first approach in a coupling strength expansion. It can be demonstrated that this leads to a form easily recognized from the Boltzmann equation if the quasiparticle approximation is used. It is seen that enforcing a quasiparticle approximation suppre

Tom D. Imbo

I consider the quantity delta(m_1m_2m_3) = M_{q_1q_2q_3} - [M_{q_1q_2bar} + M_{q_2q_3bar} + M_{q_1q_3bar}]/2, where the M&#39;s represent the ground state spin-averaged hadron masses with the indicated quark content and the m&#39;s the corresponding constituent quark masses. I assume a logarithmic interquark potential, the validity of a nonrelativistic appro

Wolfhard Janke, Stefan Kappler

We performed Monte Carlo simulations of the two-dimensional q-state Potts model with q=10, 15, and 20 to study the energy and magnetization cumulants in the ordered and disordered phase at the first-order transition point $β_t$. By using very large systems of size 300 x 300, 120 x 120, and 80 x 80 for q=10, 15, and 20, respectively, our numerical estimates p

Vikram Vyas

A representation of the continuum fermionic propagator as a sum of directed random walks on a lattice is presented. Also a random walk representation for the lattice fermionic propagators is developed for the case of the naive, the Wilson, and the Kogut-Susskind fermions. For the naive fermions the phenomenon of fermion doubling appears as having $2^{D}$ dis

Giorgio Immirzi

This is an informal review of the formulation of canonical general relativity and of its implications for quantum gravity; the various versions are compared, both in the continuum and in a discretized approximation suggested by Regge calculus. I also show that the weakness of the link with the geometric content of the theory gives rise to what I think is a s

T. Tanaka, H. Tagoshi, M. Sasaki

Using the post-Newtonian (PN) expansion technique of the gravitational wave perturbation around a Schwarzschild black hole, we calculate analytically the energy flux of gravitational waves induced by a particle in circular orbits up to the 5.5PN order, i.e. $O(v^{11})$ beyond Newtonian. By comparing the formula with numerical data, we find that the error of

Denis V. Juriev

The article is devoted to the $q_R$-conformal modular functors, which being ``deformations&#39;&#39; of the conformal modular functor (the projective representation of the category $Train(Diff_+(S^1))$, the train of the group $Diff_+(S^1)$ of all orientation preserving diffeomorphisms of a circle) in the class of all projective modular functors (the projecti

Kahren Tevosyan, A. H. MacDonald

We report on a study of virial expansions for interacting electrons in the lowest Landau level of a two-dimensional electron gas. For hard-core-model interactions, we derive analytic results valid at low temperatures and filling factors smaller than 1/3 and comment on their relationship with virial expansions for exclusion statistics models. In the high temp

Sharad Ramanathan, Daniel S. Fisher

The dynamics of tensile crack fronts restricted to advance in a plane are studied. In an ideal linear elastic medium, a propagating mode along the crack front with a velocity slightly less than the Rayleigh wave velocity, is found to exist. But the dependence of the effective fracture toughness $Γ(v)$ on the crack velocity is shown to destabilize the crack f

G. Bouzerar, A. P. Kampf, F. Schönfeld

We have calculated the magnetic excitation spectrum in frustrated and dimerized spin 1/2 Heisenberg chains for model parameters which describe the thermodynamics and low frequency spin dynamics in the spin--Peierls system $CuGeO_{3}$. As a test the chosen model is found to reproduce the lowest Raman excitation energy near $30 cm^{-1}$ in the dimerized phase.

Lorenzo Bergomi, James J. Chen

We report results on the temperature dependence of the susceptibilities of a set of MBE-grown short-period EuTe/PbTe antiferromagnetic superlattices having different EuTe layer thicknesses. In-plane and orthogonal susceptibilities have been measured and display a strong anisotropy at low temperature, confirming the occurrence of a magnetic phase transition i

Pascal Lederer

The Quantum Hall Effect of Field Induced Spin Density Wave Phases is accounted for within a weak coupling theory which assumes that in the relevant low temperature part of the phase diagram the quasi one dimensional conductor is well described by Fermi liquid theory. Recent experimental results show that sign inversion of the Hall Plateaux takes place all th

K. Hewitt, T. Devereaux, X. K. Chen, X. -Z. Wang

In a recent paper Kendziora et al concluded that the superconducting gap in overdoped Bi-2212 is isotropic. From data obtained from electronic Raman scattering measurements, their conclusion was based on the observation that pair breaking peaks occured at approximately the same frequency in different scattering geometries and that the normalized scattering i

Giulio Casati, Italo Guarneri, Giulio Maspero

We numerically analyze the transmission through a thin disordered wire of finite length attached to perfect leads, by making use of banded random Hamiltonian matrices. We compare the Landauer and the Thouless conductances, and find that they are proportional to each other in the diffusive regime, while in the localized regime the Landauer conductance is appr

Arisato Kawabata

We investigate the effect of electron-electron interactions on the conductance of quasi one-dimensional systems without potential scattering. For a finite temperature or system length, the short-range interaction is not renormalized to 0, and it gives rise to a finite correction to the conductance if we calculate it using Kubo formula. We show that this corr

R. Montagne, E. Hernandez-Garcia, A. Amengual, M. San Miguel

We consider phase turbulent regimes with nonzero winding number in the one-dimensional Complex Ginzburg-Landau equation. We find that phase turbulent states with winding number larger than a critical one are only transients and decay to states within a range of allowed winding numbers. The analogy with the Eckhaus instability for non-turbulent waves is stres

The Supernova Cosmology Project, :, A. G. Kim, S. Gabi

The Supernova Cosmology Project has discovered over twenty-eight supernovae (SNe) at 0.35 <z < 0.65 in an ongoing program that uses Type Ia SNe as high-redshift distance indicators. Here we present measurements of the ratio between the locally observed and global Hubble constants, H_0^L/H_0^G, based on the first 7 SNe of this high-redshift data set compared

T. Contini, H. Wozniak, S. Considere, E. Davoust

We have searched for dense molecular gas in three barred spiral galaxies with young starbursts, NGC 3049, 5430 and 6764, which are known Wolf-Rayet galaxies. We detected HCN in the latter two, and CS was marginally detected in NGC 6764. The dense molecular gas contents of the three galaxies are compared to those of other galaxies and to other indicators of s

Ricardo P. Schiavon, B. Barbuy, Patan D. Singh

We study the FeH Wing-Ford band at 9850 - 10200 Angstrons by means of the fit of synthetic spectra to the observations of M stars, employing recent model atmospheres. On the basis of the spectrum synthesis, we analyze the dependence of the band upon atmospheric parameters. FeH lines are a very sensitive surface gravity indicator, being stronger in dwarfs. Th

K. K. McLeod

We have obtained deep, near-IR images of nearly 100 host galaxies of nearby quasars and Seyferts. We find the near-IR light to be a good tracer of luminous mass in these galaxies. For the most luminous quasars there is a correlation between the maximum allowed B-band nuclear luminosity and the host galaxy mass, a ``luminosity/host-mass limit&#39;&#39;. Compa

S. Rauzy

A new technique for calibrating Tully-Fisher like relations by using field galaxies is proposed. Based on a null-correlation approach (NCA), the technique is insensitive to the presence of selection effects on apparent magnitude $m$ and on log line-width distance indicator $p$. This interesting property is used for discarding near by galaxies of the observed

Belinda J. Wilkes

The Infrared Space Observatory (ISO), launched in November 1995, allows us to measure the far-infrared (far-IR) emission of quasars in greater detail and over a wider energy range than previously possible. In this paper, preliminary results in a study of the 5--200 $μm$ continuum of quasars and active galaxies are presented. Comparison of the spectral energy

F. H. Briggs, E. Sorar, R. C. Kraan-Korteweg, W. van Driel

Driftscan methods are highly efficient, stable techniques for conducting extragalactic surveys in the 21cm line of neutral hydrogen. Holding the telescope still while the beam scans the sky at the sidereal rate produces exceptionally stable spectral baselines, increased stability for RFI signals, and excellent diagnostic information about system performance.

Jordi Jose, Margarita Hernanz, Alain Coc

The production of 26Al by explosions of classical novae has been computed by means of a hydrodynamic code that follows both the accretion and the explosion stages. A special emphasis has been put on the analysis of the influence of the initial abundances of the accreted envelope, as well as on the nuclear reaction rates involved. With the most recent values

Gavin Dalton, Steve Maddox, Will Sutherland, George Efstathiou

We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range, and radius from the cluster centre used to estimate the cluster richnesses. We quantif

W. M. Oxbury, C. Pauly, E. Previato

We explore some of the interplay between Brill-Noether subvarieties of the moduli space SU_C(2,K) of rank 2 bundles with canonical determinant on a smooth projective curve and 2θdivisors, via the inclusion of the moduli space into |2θ|, singular along the Kummer variety. In particular we show that the moduli space contains all the trisecants of the Kummer an

Alexander Yu. Vlasov

In the e-print is discussed a few steps to introducing of &#34;vocabulary&#34; of relativistic physics in quantum theory of information and computation (QTI&C). The behavior of a few simple quantum systems those are used as models in QTI&C is tested by usual relativistic tools (transformation properties of wave vectors, etc.). Massless and charged massive pa

H. C. Rosu, J. R. Guzmán

The simple supersymmetric approach recently used by Dutt, Gangopadhyaya, and Sukhatme [Am. J. Phys. 65 400 (1997)] for spherical harmonics is generalized to Jacobi equation, including also the intermediate Gegenbauer case

Andrew Sornborger, Sean M. Carroll, Ted Pyne

The ordering of scalar fields after a phase transition in which a group $G$ of global symmetries is spontaneously broken to a subgroup $H$ provides a possible explanation for the origin of structure in the universe, as well as leading to observable effects in condensed matter systems. The field dynamics can depend in principle on the geometry and topology of

P. Bressler, J. -L. Brylinski

We study the intersection cohomology of the theta divisors on Jacobians of nonhyperelliptic curves.

Chong Sheng Li, Robert J. Oakes, Jin Min Yang, C. -P. Yuan

We evaluate the supersymmetric (SUSY) electroweak corrections to the effect of parity nonconservation in $q {\bar q} \to t {\bar t}$ production at the Fermilab Tevatron predicted by the Minimal Supersymmetric Model (MSSM). We find that the parity nonconserving asymmetry from the SUSY electroweak and SUSY Yukawa loop corrections predicted by the minimal super

Andrea Romanino

An unified flavour model based on U(2) as flavour group is described. Besides to explain the main characteristics of the fermion spectrum, the model is predictive and agrees quantitatively with experimental data in flavour physics.

Q. H. Zhang, X. Q. Li

The probability distribution of a neutral pion fraction from independent domains of disoriented chiral condensate is characterized. The signal for the condensate is still clear for a large number of independent domains if one of them is predominant.

Michael Trunk

The pseudo--rigid body represents an example of a constrained system with a nonunimodular gauge group. This system is treated along the guidelines of an algebraic constraint quantization scheme which focusses on observable quantities, translating the vanishing of the constraints into representation conditions on the algebra of observables. The constraint whi

Hassan Chamati, Ekaterina S. Pisanova, Nocholay S. Tonchev

The quantum rotors model can be regarded as an effective model for the low-temperature behavior of the quantum Heisenberg antiferromagnets. Here, we consider a $d$-dimensional model in the spherical approximation confined to a general geometry of the form $L^{d-d&#39;}\times\infty^{d&#39;}\times L_τ^{z}$ ( $L$-linear space size and $L_τ$-temporal size) and s

A. G. Abanov, P. B. Wiegmann

We compute the angular dependence of the order parameter and tunneling amplitude in a model exhibiting topological superconductivity and sketch its derivation as a model of a doped Mott insulator. We show that ground states differing by an odd number of particles are orthogonal and the order parameter is in the d-representation, although the gap in the elect

M. Kawasaki, T. Yanagida

We derive a constraint on the cosmic density of string moduli fields in gauge-mediated supersymmetry-breaking theories by requiring that photons emitted from the unstable moduli fields should not exceed the observed X-ray backgrounds. Since mass of the moduli field lies in the range between $O(0.1)$keV and $O(1)$MeV and the decay occurs through a gravitation

Yoshio Koide

It is pointed out that the phase convention of the CKM matrix V affects texture analysis of the quark mass matrices (M_u, M_d) when we try to describe (M_u, M_d) by the observable quantities (quark masses and CKM matrix parameters) only. This is demonstrated for a case of the non-Hermitian Fritzsch-type mass matrix (tilde{M}_u, tilde{M}_d), which is a genera

Martin J. Rees

The case for collapsed objects in some X-ray binary systems continues to strengthen. But there is now even firmer evidence for supermassive black holes in galactic centres. Gravitational collapse seems to have occurred in the centres of most newly-forming galaxies, manifesting itself in a phase of quasar-like activity (which may be reactivated later). These

Kouichi Takemura

By using the non-symmetric Hermite polynomials and a technique based on the Yangian Gelfand-Zetlin bases, we decompose the space of states of the Calogero model with spin into irreducible Yangian modules, construct an orthogonal basis of eigenvectors and derive product-type formulas for norms of these eigenvectors.

Tony Gherghetta, Thomas A. Kaeding, Gordon L. Kane

We analyse in detail the supersymmetric contributions to the decay of an extra Z boson in effective rank 5 models, including the important effect of D-terms on sfermion masses. The inclusion of supersymmetric decay channels will reduce the Z&#39; branching ratio to standard model particles resulting in lower Z&#39; mass limits than those often quoted. In par

I. G. Korepanov

Here we present some eigenstates for a 2+1-dimensional model associated with a solution of the tetrahedron equation. The eigenstates include those &#34;particle-like&#34; (namely one-particle and two-particle ones), constructed in analogy with the usual 1+1-dimensional Bethe ansatz, and some simple &#34;string-like&#34; ones.

J. Twamley

For quantum systems with two dimensional configuration space we construct a physical radial momentum observable. Rescaling the radius we find the dilatonic degrees of freedom form a Weyl algebra. With this we construct the radial Wigner quasi-probability distribution function.

J. Brachmann, A. Dumitru, C. Spieles, J. Maruhn

We study the time scale for pressure equilibration in heavy ion collisions at AGS energies within the three-fluid hydrodynamical model and a microscopic cascade model (UrQMD). We find that kinetic equilibrium is reached in both models after a time of 5 fm/c (center-of-mass time). Thus, observables which are sensitive to the early stage of the reaction differ

M. Matsuo, T. Døssing, E. Vigezzi, R. A. Broglia

In order to provide a microscopic description of levels and E2 transitions in rapidly rotating nuclei with internal excitation energy up to a few MeV, use is made of a shell model which combines the cranked Nilsson mean-field and the residual surface delta two-body force. The damping of collective rotational motion is investigated in the case of a typical ra

S. Hirenzaki, H. Toki

Recently, deeply bound pionic states were found experimentally in (d,$^3$He) reactions on $^{208}$Pb. The observed spectrum showed an excellent agreement with the DWIA calculation and the dominant peak was attributed to the pionic 2p state contribution. We studied theoretically $^{206}$Pb(d,$^3$He) reactions within the same model, and found that it is very l

Stanislaw J. Szarek, Elisabeth Werner

Let $μ$ be a Gaussian measure (say, on ${\bf R}^n$) and let $K, L \subset {\bf R}^n$ be such that K is convex, $L$ is a &#34;layer&#34; (i.e. $L = \{x : a \leq < x,u > \leq b \}$ for some $a$, $b \in {\bf R}$ and $u \in {\bf R}^n$) and the centers of mass (with respect to $μ$) of $K$ and $L$ coincide. Then $μ(K \cap L) \geq μ(K) \cdot μ(L)$. This is motivate