January 2002 arXiv papers — page 18

M. Dutour

Every polyhedral cone can be described either by its facets or by its extreme rays. Computation of one description from the other is a problem that can be very complex, i.e. one encounter the combinatorial explosion. We present here several methods which allow us to use symmetries for the computation of extreme rays and facets of cones. I give an algorithm f

Yongbin Ruan

Motivated by physics, we propose two conjectures regarding the cohomology ring of the crepant resolutions of orbifolds and cohomological invariants of K-equivalent manifolds.

A. Boveia, S. James Gates, Bjorg A. Larson, W. D. Linch

We continue the development of the actions, S_{AFF}, by examining the cases where there are N fermionic degrees of freedom associated with a 0-brane. These actions correspond to the interaction of the N-extended super Virasoro algebra with the supergraviton and the associated SO(N) gauge field that accompanies the supermultiplet. The superfield formalism is

Stephen Blaha

We show the Standard Model and SuperString Theories can be naturally based on a Quantum Computer foundation. The Standard Model of elementary particles can be viewed as defining a Quantum Computer Grammar and language. A Quantum Computer in a certain limit naturally forms a Superspace upon which Supersymmetry rotations can be defined - a Continuum Quantum Co

Michael Chesterman

I extend upon the paper by Batalin and Marnelius, in which they show how to construct and quantize a gauge theory from a Hamiltonian system with second class constraints. Among the avenues explored, their technique is analyzed in relation to other well-known methods of quantization and a bracket is defined, such that the operator formalism can be fully devel

J. Llosa

We show by some counterexamples that Lagrangian sysytems with nonlocality of finite extent are not necessarily unstable.

Koh-ichi Nittoh

The Chern-Simons coupling shift is calculated within the framework of the hybrid regularization based on a local higher covariant derivative regulator. When the Yang-Mills term is present in the theory the well-know integer-shift is obtained, but is absent, the shift value is non-integer. These results show a possibility that a non-integer-shift can be deriv

Arnold Neumaier

The projection formalism for calculating effective Hamiltonians and resonances is generalized to the nonlocal and/or nonhermitian case, so that it is applicable to the reduction of relativistic systems (Bethe-Salpeter equations), and to dissipative systems modeled by an optical potential. It is also shown how to recover all solutions of the time-independent

J. W. van Holten

In general relativity, only relative acceleration has an observer-independend meaning: curvature and non-gravitational forces determine the rate at which world lines of test bodies diverge or converge. We derive the equations governing both in the conventional geometric formalism as well as using the background field method. This allows us to generalize the

L. C. Garcia de Andrade

Gravitational stability of torsion and inflaton potential in a four-dimensional spacetime de Sitter solution in scalar-tensor cosmology where Cartan torsion propagates is investigated in detail. Inflaton and torsion evolution equations are derived by making use of a Lagrangean method. Stable and unstable modes for torsion and inflatons are found. Present ast

K. S. Babu, S. M. Barr

A general analysis is made of the question whether the d=5 proton decay operators coming from exchange of colored Higgsinos can be completely eliminated in a natural way in supersymmetric grand unified models. It is shown that they can indeed be in SO(10) while at the same time naturally solving the doublet-triplet splitting problem, having only two light Hi

Claudio Coriano, Alon E. Faraggi

A general prediction of string unification is the existence of exotic states with fractional charges under the free unbroken Abelian generators of the underlying GUT symmetry. Such states may be long-lived due to the existence of weakly broken gauge, or local discrete, symmetries, and may serve as experimental probes of string theory in forthcoming cosmic ra

A. D. Martin, R. G. Roberts, W. J. Stirling, R. S. Thorne

We perform a NNLO (and a LO) global parton analysis in which we include the new precise data for deep inelastic scattering from HERA and for inclusive jet production at the Tevatron, together with the improved knowledge of the three-loop splitting functions. The results are compared with our recent NLO analyses. The LO fit produces significantly worse result

M. Chertok, K. Dienes, S. Godfrey, P. Kalyniak

We summarize some of the work done by the P3 subgroup on Alternative Models and New Ideas. The working group covered a broad range of topics including a constrained Standard Model from an extra dimension, a discussion of recent ideas addressing the strong CP problem, searches for doubly charged higgs bosons in e gamma collisions, and an update on discovery l

K. Sveshnikov, Il. Malakhov, M. Khalili, S. Fedorov

The 3-phase version of the hybrid chiral bag model, containing the phase of asymptotic freedom, the hadronization phase as well as the intermediate phase of constituent quarks, is proposed. For this model the self-consistent solutions, which take into account the fermion vacuum polarization effects, are found in 1+1 D. The renormalized total energy of the ba

Marcus Bleicher, Jörg Aichelin

The production and the observability of $Λ(1520)$, $K^0(892)$ $Φ$ and $Δ(1232)$ hadron resonances in central Pb+Pb collisions at 160 AGeV is addressed. The rescattering probabilities of the resonance decay products in the systems evolution are studied. Strong changes in the reconstructable particle yields and spectra between chemical and thermal freeze-out a

I. A. Sokalski, E. V. Bugaev, S. I. Klimushin

Chain of calculations which have to be performed to predict any kind of signal in a deep underwater/ice neutrino detector necessarily includes the lepton propagation through thick layers of matter, as neutrino can be observed only by means of leptons (muons, first of all, due to their large ranges) that are generated in $νN \to l N$ interactions. Thus, the m

A. Ali

We discuss precision tests of the standard model in radiative and semileptonic rare B-decays and CP-violating asymmetries, and possible signatures of supersymmetry in these processes. Motivated by current data, and with an eye on the forthcoming measurements, we restrict ourselves to the processes in which the bench marks set by the standard model have eithe

M. Diehl

I discuss how generalized parton distribution probe various aspects of QCD bound states. Topics include the interplay between transverse and longitudinal structure, quantum mechanical interference, orbital angular momentum, helicity flip, and higher-spin targets.

Mikhail A. Ivanov

We present the results of a study of the semileptonic decays of the $B_c$-meson and the lowest lying doubly heavy baryons using the relativistic quark model. We do not employ a heavy quark mass expansion but keep the masses of the heavy quarks and hadronss finite. We calculate all relevant form factors and decay rates.

M. Slusarczyk, A. Wereszczynski

We show that in the dual version of the generalized Dick model monopole-anti-monopole pairs have finite energy. It is possible to use the potential between monopole and anti-monopole to find the mass spectrum of the glueballs. The results are discussed in connection with the Faddeev-Niemi model and toroidal soliton solutions. Some others finite energy config

Elena Gubankova

We consider the eigenstate problem for a Hamiltonian operator of the field theory. Methods of construction the effective field theoretical Hamiltonians for which the eigenstate problem may be solved are discussed. In particular, we discuss the method of flow equations from a general perspective as well as in application to the gauge field theories. Flow equa

R. Silva, J. A. S. Lima, M. O. Calvão

The first-order general relativistic theory of a generic dissipative (heat-conducting, viscous, particle-creating) fluid is rediscussed from a unified covariant frame-independent point of view. By generalizing some previous works in the literature, we derive a formula for the temperature variation rate, which is valid both in Eckart's (particle) and in t

P. Bizoń, A. Wasserman

We present a detailed analytical study of spherically symmetric self-similar solutions in the SU(2) sigma model coupled to gravity. Using a shooting argument we prove that there is a countable family of solutions which are analytic inside the past self-similarity horizon. In addition, we show that for sufficiently small values of the coupling constant these

Marc Mars, Jose M. M. Senovilla

Axisymmetric spacetimes with a conformal symmetry are studied and it is shown that, if there is no further conformal symmetry, the axial Killing vector and the conformal Killing vector must commute. As a direct consequence, in conformally stationary and axisymmetric spacetimes, no restriction is made by assuming that the axial symmetry and the conformal time

Leonard S. Abrams

Schwarzschild's actual exterior solution (Gs) is resurrected and together with the manifold M is shown to constitute a space-time possessing all the properties historically thought to be required of a point mass. On the other hand, the metric that today is ascribed to Schwarzschild, but which was in fact first obtained by Droste and Weyl, is shown to giv

R. S. Ward

In flat space-time, sigma-model strings and textures are both unstable to collapse and subsequent decay. With sufficient cosmological expansion, however, they are stable in a generalized sense: a small perturbation will cause them to change their shape, but they do not decay. The current rate of expansion is sufficient to stabilize strings, but not textures.

Ron Holzman, Noa Kfir-Dahav, Dov Monderer, Moshe Tennenholtz

This paper analyzes individually-rational ex post equilibrium in the VC (Vickrey-Clarke) combinatorial auctions. If $Σ$ is a family of bundles of goods, the organizer may restrict the participants by requiring them to submit their bids only for bundles in $Σ$. The $Σ$-VC combinatorial auctions (multi-good auctions) obtained in this way are known to be indivi

Igor Rivin

We analyze completely the convergence speed of the \emph{batch learning algorithm}, and compare its speed to that of the memoryless learning algorithm and of learning with memory. We show that the batch learning algorithm is never worse than the memoryless learning algorithm (at least asymptotically). Its performance \emph{vis-a-vis} learning with full memor

A. Kaminski, S. Das Sarma

We theoretically study the development of spontaneous magnetization in diluted magnetic semiconductors as arising from a percolation of bound magnetic polarons. Within the framework of a generalized percolation theory we derive analytic expressions for the Curie temperature and the magnetization, obtaining excellent quantitative agreement with Monte Carlo si

Sudip Chakravarty, Chetan Nayak, Sumanta Tewari, Xiao Yang

We study the behavior of the Hall coefficient, $R_H$, in a system exhibiting $d_{{x^2}-{y^2}}$ density-wave (DDW) order in a regime in which the carrier concentration, $x$, is tuned to approach a quantum critical point at which the order is destroyed. At the mean-field level, we find that $n_{\rm Hall}=1/R_H$ evinces a sharp signature of the transition. Ther

Nikolai V. Brilliantov, Vitali V. Malinin, Roland R. Netz

An accurate and systematic equation of state for the hard-core one-component plasma (HCOCP) is obtained. The result is based on the Hubbard-Schofield transformation which yields the field-theoretical Hamiltonian, with coefficients expressed in terms of equilibrium correlation functions of the reference hard-core fluid. Explicit calculations were performed us

V. S. Zotev, R. Orbach

The scaling of the magnetic field dependence of the remanent magnetization for different temperatures and different spin-glass samples is studied. Particular attention is paid to the effect of the de Almeida-Thouless (AT) critical line on spin-glass dynamics. It is shown that results of the mean-field theory of aging phenomena, with two additional experiment

Subinoy Das, Pallab Goswami, J. K. Bhattacharjee

A variational treatment for a two-electron quantum dot (the artificial helium atom) is proposed which leads to exact answer for the ground state energy. Depending on the magnetic field value the singlet-triplet and triplet-triplet transitions of the ground state take place, which are captured in our solution. Using the same variational technique we find corr

Ludovic Bellon, Sergio Ciliberto

The validity of fluctuation dissipation relations in an aging system is studied in a colloidal glass during the transition from a fluid-like to a solid-like state. The evolution of the rheological and electrical properties is analyzed in the range $1Hz - 40Hz$. It is found that at the beginning of the transition the fluctuation dissipation relation is strong

Shu-Chiuan Chang, Robert Shrock

We present a set of general results on structural features of the $q$-state Potts model partition function $Z(G,q,v)$ for arbitrary $q$ and temperature Boltzmann variable $v$ for various lattice strips of arbitrarily great width $L_y$ vertices and length $L_x$ vertices, including (i) cyclic and Möbius strips of the square and triangular lattice, and (ii) sel

M. A. Anisimov, A. F. Kostko, J. V. Sengers

We show that the approach to asymptotic fluctuation-induced critical behavior in polymer solutions is governed by a competition between a correlation length diverging at the critical point and an additional mesoscopic length-scale, the radius of gyration. Accurate light-scattering experiments on polystyrene solutions in cyclohexane with polymer molecular wei

Hari M. Gupta, Jose R. Campanha

We study the growth dynamics of the size of manufacturing firms considering competition and normal distribution of competency. We start with the fact that all components of the system struggle with each other for growth as happened in real competitive bussiness world. The detailed quantitative agreement of the theory with empirical results of firms growth ba

Douglas B. Abraham, Rodolfo Cuerno, Esteban Moro

A microscopic, driven lattice gas model is proposed for the dynamics and spatio-temporal fluctuations of the precursor film observed in spreading experiments. Matter is transported both by holes and particles, and the distribution of each can be described by driven diffusion with a moving boundary. This picture leads to a stochastic partial differential equa

Kent R. Thurber, Lee E. Harrell, Raul Fainchtein, Doran D. Smith

We applied the recently developed technique of force-detected nuclear magnetic resonance (NMR) to observe 71Ga, 69Ga, and 75As in GaAs. The nuclear spin-lattice relaxation time is 21$\pm$5 min for 69Ga at $\sim 5$ K and 4.6 Tesla. We have exploited this long relaxation time to first create and then observe spatially varying nuclear spin polarization within t

O. Vyaselev, K. Arai, K. Kobayashi, J. Yamazaki

We report Cd NMR and Re NQR studies on Cd2Re2O7, the first superconductor among pyrochlore oxides Tc=1 K. Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below Tc exhibits a pronounced coherence peak and behaves within the weak-coupling BCS theory with nearly isotropic energy gap. Cd

Andreas Schadschneider, Michael Schreckenberg

Recently, Huang and Lin suggested a combination of two successfull mean-field theories, the 2-cluster approximation and paradisical mean-field, for the Nagel-Schreckenberg cellular automaton model of traffic flow. We argue that this new approximation is inconsistent since it violates the Kolmogorov conditions.

J. Bouttier, P. Di Francesco, E. Guitter

We address the general problem of hard objects on random lattices, and emphasize the crucial role played by the colorability of the lattices to ensure the existence of a crystallization transition. We first solve explicitly the naive (colorless) random-lattice version of the hard-square model and find that the only matter critical point is the non-unitary Le

B. Jancovici

When described in a grand canonical ensemble, a finite Coulomb system exhibits charge fluctuations. These fluctuations are studied in the case of a classical (i.e. non-quantum) system with no macroscopic average charge. Assuming the validity of macroscopic electrostatics gives, on a three-dimensional finite large conductor of volume $V$, a mean square charge

V. I. Yukalov

The problem of describing optical turbulent structures, arising in resonant media with high Fresnel numbers, is reviewed. The consideration is based on the probabilistic approach to pattern selection, ascribing a probability distribution of patterns to systems with multiple possible structures. The most probable structure corresponds to the minimal expansion

Huijie Yang, Fangcui Zhao, Yizhong Zhuo, Xizhen Wu

By means of the concepts of factorial moment, return map and NM estimator, we analyze some responses of a HH neuron to various types of spike-train inputs. The corresponding fractal dimensions and values of NM estimators can describe the correlation characteristics quantitatively. It is found that all the intervals of successive output spikes may obey a powe

Masaaki Nakamura, Synge Todo

We propose an order parameter to characterize valence-bond-solid (VBS) states in quantum spin chains, given by the ground-state expectation value of a unitary operator appearing in the Lieb-Schultz-Mattis argument. We show that the order parameter changes the sign according to the configuration of the valence bonds. This allows us to determine the phase tran

Yu. G. Gurevich, I. N. Volovichev

It is shown that in general electron gas heating inevitably results in the change of the carrier concentration in the conduction band. It is proved, that this change, as a rule, leads to the kinetic coefficient nonlinearity of the same order, as the change of mobility does. The conditions are determined, when this change can be neglected.

Gianni Settanni, Trinh Xuan Hoang, Cristian Micheletti, Amos Maritan

The relevance of various residue positions for the stability and the folding characteristics of the prion protein are investigated by using molecular dynamics simulations of models exploiting the topology of the native state. Highly significant correlations are found between the most relevant sites in our analysis and the single point mutations known to be a

E. Ardonne, F. J. M. van Lankvelt, A. W. W. Ludwig, K. Schoutens

We propose a series of paired spin-singlet quantum Hall states, which exhibit a separation of spin and charge degrees of freedom. The fundamental excitations over these states, which have filling fraction ν=2/(2m+1) with m an odd integer, are spinons (spin-1/2 and charge zero) or fractional holons (charge +/- 1/(2m+1) and spin zero). The braid statistics of

Weidong Li, Alexei V. Filippenko, Schuyler D. Van Dyk, Jingyao Hu

We present photometry of 12 recent supernovae (SNe) recovered in a {\it Hubble Space Telescope} Snapshot program, and tie the measurements to earlier ground-based observations, in order to study the late-time evolution of the SNe. Many of the ground-based measurements are previously unpublished, and were made primarily with a robotic telescope, the Katzman A

Colleen A. Wilson, Mark H. Finger, M. J. Coe, Silas Laycock

Using BATSE and RXTE observations from 1991 April to 2001 August we have detected 71 outbursts from 82 periastron passages of EXO 2030+375, a 42-second transient X-ray pulsar with a Be star companion, including several outbursts from 1993 August to 1996 April when the source was previously believed to be quiescent. Combining BATSE, RXTE, and EXOSAT data we h

O. G. Benvenuto, A. H. Corsico, L. G. Althaus, A. M. Serenelli

We study the structural characteristic of the variable DA white dwarf G117B-15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical description as well as several processes responsible for the occurrence of element diffusion. We have considered several th

A. H. Corsico, O. G. Benvenuto, L. G. Althaus, A. M. Serenelli

We explore the effects of element diffusion due to gravitational settling and thermal and chemical diffusion on the pulsational properties of DA white dwarfs. To this end, we employ an updated evolutionary code coupled with a pulsational, finite difference code for computing the linear, non-radial g-modes in the adiabatic approximation. We follow the evoluti

S. M. Molnar, M. Birkinshaw, R. F. Mushotzky

We discuss how the space of possible cosmological parameters is constrained by the angular diameter distance function, D_A(z), as measured using the SZ/X-ray method which combines Sunyaev-Zel'dovich (SZ) effect and X-ray brightness data for clusters of galaxies. New X-ray satellites, and ground-based interferometers dedicated to SZ observations, should s

Avishai Dekel, Jonathan Devor, Itai Arad

We show how the buildup of halos by merging satellites forces an inner cusp, with a density profile ρ\propto r^{-α} where α\to α_a \gsim 1$. Our analysis is based on a new prescription for tidal stripping as a function of α(r), using a simple toy model which matches N-body simulations. In a core of α< 1 there is tidal compression rather than stripping and th

Casey Papovich, Mark Dickinson, Harry Ferguson

We present constraints on the stellar-mass distribution of distant galaxies. These stellar-mass estimates derive from fitting population-synthesis models to the galaxies&#39; observed multi-band spectrophotometry. We discuss the complex uncertainties (both statistical and systematic) that are inherent to this method, and offer future prospects to improve the

Jarrod R. Hurley, Christopher A. Tout, Onno R. Pols

We present a rapid binary evolution algorithm that enables modelling of even the most complex binary systems. In addition to all aspects of single star evolution, features such as mass transfer, mass accretion, common-envelope evolution, collisions, supernova kicks and angular momentum loss mechanisms are included. In particular, circularization and synchron

Patrick R. Durrell, Robin Ciardullo, John J. Feldmeier, George H. Jacoby

We have used the WFPC2 camera of the Hubble Space Telescope to obtain deep F814W images of a blank field in the Virgo Cluster located 41 arcmin northwest of M87. We perform star counts in that field, and in another Virgo field observed by Ferguson, Tanvir & von Hippel (1998), and show that, when compared to the Hubble Deep Field North and South, the Virgo Cl

J. P. Aufdenberg, P. H. Hauschildt, E. Baron, T. E. Nordgren

A stellar wind module has been developed for the PHOENIX stellar atmosphere code for the purpose of computing non-LTE, line-blanketed, expanding atmospheric structures and detailed synthetic spectra of hot luminous stars with winds. We apply the code to observations of Deneb, for which we report the first positive detections of mm and cm emission (obtained u

Jarrod R. Hurley, Michael M. Shara

The recent availability of special purpose computers designed for calculating gravitational interactions of N-bodies at extremely high speed has provided the means to model globular clusters on a star-by-star basis for the first time. By endeavouring to make the N-body codes that operate on these machines as realistic as possible, the addition of stellar evo

Steve Warren, Paul Hewett

We estimate the number of z~7 quasars that will be discovered in the Large Area Survey (LAS) element of the UKIRT Infrared Deep Sky Survey (UKIDSS). The LAS will cover 4000 sq degs of the northern sky to K=18.4, which is 3 mag. deeper than 2MASS. The Sloan Digital Sky Survey has extended the quasar redshift limit to z=6.3. We demonstrate that to reach higher

M. Hoeft, J. P. Muecket, P. Heide

We investigate the energy release due to the large-scale structure formation and the subsequent transfer of energy from larger to smaller scales. We calculate the power spectra for the large-scale velocity field and show that the coupling of modes results in a transfer of power predominately from larger to smaller scales. We use the concept of cumulative ene

L. L. Kiss, N. Gogh, J. Vinko, G. Furesz

We present an analysis of low- and medium resolution spectra of the very fast nova, Nova Cygni 2001/2 (V2275 Cyg) obtained at nine epochs in August, September and October, 2001. The expansion velocity from hydrogen Balmer lines is found to be 2100 km/s, although early H-alpha profile showed a weak feature at -3500 km/s, too. The overall appearance of the opt

A. De Rujula

The Cannonball Model is based on the hypothesis that GRBs and their afterglows are made in supernova explosions by relativistic ejecta similar to the ones observed in quasars and microquasars. Its predictions are simple, and analytical in fair approximations. The model describes well the properties of the $γ$-rays of GRBs. It gives a very simple and extremel

Shardha Jogee, Andrew J. Baker, Kazushi Sakamoto, Nick Z. Scoville

With the recent advent of large interferometric surveys, we can now probe the physical conditions, dynamics, and star-forming properties of molecular gas in the central kpc of starbursts and active galactic nuclei. We present results from the high-resolution (~ 100 pc) interferometric survey of molecular gas in the inner kpc of nearby starbursts (Jogee, Kenn

N. Drory, R. Bender, J. Snigula, G. Feulner

We derive the number density evolution of massive field galaxies in the redshift range 0.4 < z < 1.2 using the K-band selected field galaxy sample from the Munich Near-IR Cluster Survey (MUNICS). We rely on spectroscopically calibrated photometric redshifts to determine distances and absolute magnitudes in the rest-frame K-band. To assign mass-to-light ratio

L. Nicastro, G. Calderone

SDAMS is the ensemble of database + software packages aimed to the archiving, quick-look analysis, off-line analysis, network accessibility and plotting of the SPOrt produced data. Many of the aspects related to data archiving, analysis and distribution are common to almost all the astronomical experiments. SDAMS ambition is to face and solve problems like a

Tae-Sun Kim, Stefano Cristiani, Sandro D&#39;Odorico

Using a new, increased dataset of 7 QSOs from VLT/UVES observations combined with one QSO from the literature, the minimum Doppler parameters as a function of neutral hydrogen column density N(HI), b_c(N), of the Lyman-alpha forest has been derived at three redshifts z = 2.1, 3.3 and 3.8. When incompleteness of the number of the observed lines towards lower

Sivakumar G. Manickam, Sandip K. Chakrabarti

The dynamics of accretion onto a schwarzschild black hole is studied using Paczynski-Wiita pseudo newtonian potential. Steady state solution of the flow equations is obtained using thin disc approximation, including the effect of bremsstrahlung cooling in the energy equation. The topology of transonic solutions are got and the conditions for shock formation

S. Jogee

I present a study of the molecular gas and star formation (SF) properties in the inner few kpc of the brightest nearby M82-class starbursts and control non-starbursts, based on high resolution CO (J=1--0) observations, optical and NIR images, along with published radio continuum and Br-gamma data. I outline the marked differences between molecular gas in the

Jozef Klacka

Discussion of different types of osculating orbital elements for motion of real dust particle under the action of electromagnetic radiation in the central gravitational field is presented. It is shown that physically correct access is based on gravitational acceleration as the only radial acceleration -- ``radiation pressure&#39;&#39; is not included in the

E. Poretti, C. Koen, M. Bossi, E. Rodriguez

We discuss new photometric data collected on the gamma Dor variables HD 224945 and HD 224638. Multiperiodicity was detected in both stars, thanks to the clear spectral window of a multisite campaign that involved five observatories. HD 224945 shows the shortest period among the gamma Dor stars, i.e., 0.3330 d. The pulsation behaviour is very different: HD 22

Asif ud-Doula, Stanley P. Owocki

We present numerical magnetohydrodynamic (MHD) simulations of the effect of stellar dipole magnetic fields on line-driven wind outflows from hot, luminous stars. Unlike previous fixed-field analyses, the simulations here take full account of the dynamical competition between field and flow, and thus apply to a full range of magnetic field strength, and withi

Steve Dawson, Hyron Spinrad, Arjun Dey, Wil van Breugel

We report the serendipitous detection in high-resolution optical spectroscopy of a strong, asymmetric Ly-alpha emission line at z = 5.190. The detection was made in a 2.25 hour exposure with the Echelle Spectrograph and Imager on the Keck II telescope through a spectroscopic slit of dimensions 1&#34; x 20&#34;. The progenitor of the emission line, J123649.2+

M. Hashimoto

We discuss the production of the composite Higgs boson in topcolor models via the gluon fusion process. We consider the contribution of color-octet massive gauge bosons (colorons) strongly interacting with the top quark, in addition to nonstandard contributions of the top-Yukawa coupling and heavy colored fermions other than the top quark. In order to estima

A. D. Dolgov

A review of Big Bang Nucleosynthesis (BBN) is presented. Observations of deuterium and helium-4 are discussed. Some BBN restrictions on non-standard physics, especially on neutrino properties and time-variation of fundamental constants are given.

V. Gusynin, M. Hashimoto, M. Tanabashi, K. Yamawaki

We investigate dynamical chiral symmetry breaking in vector-like gauge theories in $D$ dimensions with ($D-4$) compactified extra dimensions, based on the gap equation (Schwinger-Dyson equation) and the effective potential for the bulk gauge theories within the improved ladder approximation. The non-local gauge fixing method is adopted so as to keep the ladd

V. K. Dobrev

We give a constructive classification of the positive energy (lowest weight) unitary irreducible representations of the D=6 superconformal algebras osp(8*/2N). Our results confirm all but one of the conjectures of Minwalla (for N=1,2) on this classification. Our main tool is the explicit construction of the norms of the states that has to be checked for posi

I. Sh. Averbukh, R. Arvieu, M. Leibscher

Semiclassical catastrophes in the dynamics of a quantum rotor (molecule) driven by a strong time-varying field are considered. We show that for strong enough fields, a sharp peak in the rotor angular distribution can be achieved via time-domain focusing phenomenon, followed by the formation of angular rainbows and glory-like angular structures. Several scena

Thomas Gilbert, Victor S. L&#39;vov, Anna Pomyalov, Itamar Procaccia

We consider shell models that display an inverse energy cascade similar to 2-dimensional turbulence (together with a direct cascade of an enstrophy-like invariant). Previous attempts to construct such models ended negatively, stating that shell models give rise to a &#34;quasi-equilibrium&#34; situation with equipartition of the energy among the shells. We s

Igor Rivin

Motivated by a probabilistic analysis of a simple game (itself inspired by a problem in computational learning theory) we introduce the \emph{moment zeta function} of a probability distribution, and study in depth some asymptotic properties of the moment zeta function of those distributions supported in the interval [0, 1]. One example of such zeta functions

F. Cannata, M. V. Ioffe, D. N. Nishnianidze

Two new methods for investigation of two-dimensional quantum systems, whose Hamiltonians are not amenable to separation of variables, are proposed. 1)The first one - $SUSY-$ separation of variables - is based on the intertwining relations of Higher order SUSY Quantum Mechanics (HSUSY QM) with supercharges allowing for separation of variables. 2)The second on

Joshua Feinberg

We study the spectrum of stable static fermion bags in the 1+1 dimensional Gross-Neveu model with $N$ flavors of Dirac fermions, in the large $N$ limit. In the process, we discover a new kink, heavier than the Callan-Coleman-Gross-Zee (CCGZ) kink, which is marginally stable (at least in the large $N$ limit). The connection of this new kink and the conjecture

Guang-jiong Ni

Based on experimental discovery that the mass-square of neutrino is negative, a quantum equation for superluminal neutrino is proposed in comparison with Dirac equation and Dirac equation with imaginary mass. A virtual particle may also be viewed as superluminal one. Both the basic symmetry of space-time inversion and the maximum violation of space-inversion

Sabine Jeschonnek, J. W. Van Orden

Quark-hadron duality is an interesting and potentially very useful phenomenon, as it relates the properly averaged hadronic data to a perturbative QCD result in some kinematic regions. While duality is well established experimentally, our current theoretical understanding is still incomplete. We employ a simple model to qualitatively reproduce all the featur

R. D. Field

The leading-log order QCD hard scattering Monte-Carlo models of HERWIG, ISAJET, and PYTHIA are used to study the sources of b-quarks at the Tevatron. The reactions responsible for producing b and bbar quarks are separated into three categories; flavor creation, flavor excitation, and parton-shower/fragmentation. Flavor creation corresponds to the production

J. P. Lansberg

Different theoretical models which attempt to describe hadronic production of heavy quarkonia are reviewed. Firstly, we consider the Color Singlet Model and point out the large discrepancies between the theoretical predictions and the results from the Tevatron detectors. Then some other models are introduced, quickly discussed and confronted with experimenta

O. D. Chernavskaya, I. I. Royzen

The up-dated three-phase concept of nuclear matter evolution in course of cooling down - from the phase of quark-qluon plasma (QGP) through the intermediate phase allowing for massive constituent quarks (valons), pions and kaons (QPK) to the phase of hadronic matter (H) - is exploited for the treatment of relative hadronic yields in the central region of hea

Sachiko Takeuchi, Kiyotaka Shimizu

In this paper, we investigate the short-range repulsion given by the quark cluster model employing an inverse scattering problem. We find that the local potential which reproduces the same phase shifts to those given by the quark cluster model has a strong repulsion at short distances in the NN1s0 channel. There, however, appears an attractive pocket at very

P. Klepac

Cylindrically symmetric stationary spacetimes are examined in the framework of string-inpired generalized theory of gravity. In four dimensions this theory contains a dilatonic scalar field in addition to gravity. A charged perfect fluid representing fermionic matter is also considered. Explicit solution is given and a discussion of the geometrical propertie

J. Davidsen, N. Luethje

Contrary to the recently published results by Daerden and Vanderzande [Phys. Rev. E 53, 4723 (1996)], we show that the time correlation function in the random-neighbor version of the Bak-Sneppen model can be well approximated by an exponential giving rise to a 1/f2 power spectrum.

A. I. D&#39;yachenko, V. Yu. Tarenkov, A. V. Abal&#39;oshev, S. J. Lewandowski

We report tunneling measurements of the electron-phonon (e-ph) interaction in superconducting MgB$_2$ using the MgB$_2$-I-Nb junctions, where I stands for insulator. The phonon structure in tunneling density of states in MgB$_2$ clearly indicates strong e-ph coupling for the E$_{2g}$ in-plane boron phonons in a narrow range around 60 meV. The Eliashberg spec

M. Ozana, A. Shelankov, J. Tobiska

The applicability of the quasiclassical theory of superconductivity in Josephson multi-layer structures is analyzed. The quasiclassical approach is compared with the exact theory based on the Bogoliubov - de Gennes equation. The angle and energy resolved (coarse-grain) currents are calculated using both techniques. It is shown that the two approaches agree i

J. Davidsen, H. G. Schuster

We present a simple stochastic mechanism which generates pulse trains exhibiting a power law distribution of the pulse intervals and a $1/f^α$ power spectrum over several decades at low frequencies with $α$ close to one. The essential ingredient of our model is a fluctuating threshold which performs a Brownian motion. Whenever an increasing potential $V(t)$

Matthew J. W. Dodgson

In very anisotropic layered superconductors (e.g. Bi$_2$Sr$_2$CaCu$_2$O$_x$) a tilted magnetic field can penetrate as two co-existing lattices of vortices parallel and perpendicular to the layers. At low out-of-plane fields the perpendicular vortices form a set of isolated vortex chains, which have recently been observed in detail with scanning Hall-probe me

G. -q. Zheng, H. Ozaki, Y. Kitaoka, P. Kuhns

We report the spin Knight shift (K_s) and the nuclear spin-lattice relaxation rate (1/T_1) in the vortex state as a function of magnetic field (H) up to 28 T in the high-T_c superconductor TlSr_{2}CaCu_2O_{6.8} (T_c=68 K). At low temperatures well below T_{c}, both K_s and 1/T_1 measured around the middle point between two nearest vortices (saddle point) inc

Stephane Goriely, Jordi Jose, Margarita Hernanz, Marc Rayet

He-accreting white dwarfs with sub-Chandrasekhar mass are revisited. The impact of the use of an extended reaction network on the predicted energy production and characteristics of the detonating layers is studied. It is shown that the considered scenario can be the site of an $α$p-process combined with a p-process and with a variant of the rp-process we ref

Y. Farzan, A. Yu. Smirnov

The area of the unitarity triangle is a measure of CP-violation. We introduce the leptonic unitarity triangles and study their properties. We consider the possibility of reconstructing the unitarity triangle in future oscillation and non-oscillation experiments. A set of measurements is suggested which will, in principle, allow us to measure all sides of the

Seiichiro Onari, Kazuhiko Kuroki, Ryotaro Arita, Hideo Aoki

In order to study whether the inter-band nesting can favor superconductivity arising from electron-electron repulsion in a three-dimensional system, we have looked at the repulsive Hubbard model on a stack of honeycomb (i.e., non-Bravais) lattices with the FLEX method, partly motivated by the superconductivity observed in MgB2. By systematically changing the