December 1997 arXiv papers — page 9

V. D. Dzhunushaliev

It is supposed that in our Universe with compactified extra dimensions (ED) the domains exist with noncompactified ED. Such domain can be a wormhole-like solution in multidimensional gravity (MD), located between two null surfaces. With the availability of compactification mechanism this MD domain can be joined on null surfaces with two black holes filled by

Fotini Markopoulou, Lee Smolin

The space of states and operators for a large class of background independent theories of quantum spacetime dynamics is defined. The SU(2) spin networks of quantum general relativity are replaced by labelled compact two-dimensional surfaces. The space of states of the theory is the direct sum of the spaces of invariant tensors of a quantum group G_q over all

O. Bertolami, P. V. Moniz

We introduce the set of constraints the wave function of the Universe has to satisfy in order to describe an Universe undergoing through the process of spontaneous breaking of supersymmetry and discuss the way this may lead to the emergence of classical spacetime.

L. I. Plimak, M. Fleischhauer, M. J. Collett, D. F. Walls

A diagram approach to classical nonlinear stochastic field theory is introduced. This approach is intended to serve as a link between quantum and classical field theories, resulting in an independent constructive characterisation of the measure in Feynman path integrals in terms of stochastic differential equations for the paths.

L. Vasiliu-Doloc, J. W. Lynn, Y. M. Mukovskii, A. A. Arsenov

Cold neutron triple-axis measurements have been used to investigate the nature of the long-wavelength spin dynamics in strongly-doped La$_{1-x}$Sr$_{x}$MnO$_3$ single crystals with $x$=0.2 and 0.3. Both systems behave like isotropic ferromagnets at low T, with a gapless ($E_0 < 0.02$ meV) quadratic dispersion relation $E = E_0 + Dq^2$. The values of the spin

A. A. Aligia, E. R. Gagliano

We consider a half-filled generalized Hubbard chain with electron-hole symmetric correlated hopping and on-site and nearest-neighbor repulsions U and V respectively. In addition to the insulating charge- and spin-density wave phases for large V and U respectively, we identify a phase with dominant superconducting correlations at large distances for small U a

C. Panagopoulos, J. R. Cooper, T. Xiang

We report the temperature T and oxygen concentration dependences of the penetration depth of grain-aligned YBa_2Cu_3O_{7-δ} with δ= 0.0, 0.3 and 0.43. The values of the in-plane λ_{ab}(0) and out-of-plane λ_{c}(0) penetration depths, the low temperature linear term in λ_{ab}(T), and the ratio λ_{c}(0) /λ_{ab}(T) were found to increase with increasing $δ$. Th

J. Schnack

The model quantum system of fermions in a one dimensional harmonic oscillator potential is investigated by a molecular dynamics method at constant temperature. Although in quantum mechanics the equipartition theorem cannot be used like in the Nose-Hoover-thermostat it is possible to couple an additional degree of freedom to the system which acts as a thermom

N. B. Kopnin, G. E. Volovik

The condition for the appearance of event horizon is considered in such pair-correlated systems (superfluids and superconductors) where the fermionic quasiparticles obey the &#34;relativistic&#34; equations. In these systems, the Landau critical velocity of superflow corresponds to the speed of light. In conventional systems, such as s-wave superconductors,

Raffaele Cafiero, Andrea Gabrielli, Miguel A. Muñoz

New theoretical and numerical analysis of the one-dimensional contact process with quenched disorder are presented. We derive new scaling relations, different from their counterparts in the pure model, which are valid not only at the critical point but also away from it due to the presence of generic scale invariance. All the proposed scaling laws are verifi

W. Knospe, L. Santen, A. Schadschneider, M. Schreckenberg

We investigate the effect of quenched disorder in the Nagel-Schreckenberg model of traffic flow. Spatial inhomogenities, i.e. lattice sites where the braking probability is enlarged, are considered as well as particle disorder, i.e. cars of a different maximum velocity. Both types of disorder lead to segregated states.

Michel Caffarel, Rémy Mosseri

The Hubbard model is exactly solved for two particles with opposite spins on d-dimensional hypercubes. It is shown that the spectrum can be separated into two parts: a trivial (U-independent) part resulting from symmetries of hypercubes and a non-trivial part expressed as a single-impurity problem on a set of finite chains of size $d^\prime+1$ ($d^\prime \le

F. Daerden, C. Vanderzande

We perform extensive simulations of the sandpile model on a Sierpinski gasket. Critical exponents for waves and avalanches are determined. We extend the existing theory of waves to the present case. This leads to an exact value for the exponent $τ_w$ which describes the distribution of wave sizes: $τ_w = \ln{(9/5)}/\ln{3}$. Numerically, it is found that the

M. onoda, I. Ichinose, T. Matsui

Being motivated by recent experimental data on YBaCuO, we calculate dc resistivity in the spin-gap state of charge- spin-separated t-J model by using a massive gauge theory of holons and spinons.The result shows it deviates downward from the T-linear behavior below the spin-gap onset temperature.

Sharad Ramanathan, Daniel S. Fisher

The dynamics of planar crack fronts in hetergeneous media near the critical load for onset of crack motion are investigated both analytically and by numerical simulations. Elasticity of the solid leads to long range stress transfer along the crack front which is non-monotonic in time due to the elastic waves in the medium. In the quasistatic limit with insta

Alexander Bratkovsky

Direct tunneling in ferromagnetic junctions is compared with impurity-assisted, surface state assisted, and inelastic contributions to a tunneling magnetoresistance (TMR). Theoretically calculated direct tunneling in iron group systems leads to about a 30% change in resistance, which is close to experimentally observed values. It is shown that the larger obs

Luca Salasnich

We review the paper &#39;Integrability of the S-Matrix vs Integrability of the Hamiltonian&#39; by C. Jung and T.H. Seligman (Phys. Rep. 285, 77-141 (1997)). This paper deals with the connection between the integrability of the scattering matrix $S$ and the integrability of the Hamiltonian $H$ for classical and quantum Hamiltonian systems.

Fausto Borgonovi, Italo Guarneri, Felix Izrailev

The Hamiltonian conservative system of two interacting particles has been considered both in classical and quantum description. The quantum model has been realized using a symmetrized two-particle basis reordered in the unperturbed energy. Main attention is paid to the structure of chaotic eigenfunctions (EF) and to the local spectral density of states (LDOS

Robert C. Kennicutt,

Measurements of H-alpha, HI, and CO distributions in 61 normal spiral galaxies are combined with published far-infrared and CO observations of 36 infrared-selected starburst galaxies, in order to study the form of the global star formation law, over the full range of gas densities and star formation rates (SFRs) observed in galaxies. The disk-averaged SFRs a

S. Perlmutter, G. Aldering, M. Della Valle, S. Deustua

The ultimate fate of the universe, infinite expansion or a big crunch, can be determined by measuring the redshifts, apparent brightnesses, and intrinsic luminosities of very distant supernovae. Recent developments have provided tools that make such a program practicable: (1) Studies of relatively nearby Type Ia supernovae (SNe Ia) have shown that their intr

M. Hanasz, H. Lesch

We present a new fast dynamo model for galactic magnetic fields, which is based on the Parker-shearing instability and magnetic reconnection, in the spirit of the model proposed by Parker (1992). We introduce a new scenario of flux tube interactions and estimate the dynamo transport coefficient basing on simple geometrical arguments. The obtained expressions

John K. Cannizzo

We present computations for the accretion disk limit cycle model in an attempt to explain the empirical relation for dwarf nova outbursts between the peak visual absolute magnitude and orbital period found by Warner. For longer period systems one sees intrinsically brighter outbursts. This is accounted for in the limit cycle model by the scaling with radius

C. Motch, P. Guillout, F. Haberl, J. Krautter

We report on optical searches in the error circles of 93 ROSAT survey sources located at low galactic latitudes (|b| < 20 deg). These sources were extracted from the ROSAT Galactic Plane Survey using various selection criteria on hardness ratio, X-ray and optical brightness and integrated galactic absorption in the direction of the source. We find optical id

Corinne Charbonnel, Jeffery A. Brown, George Wallerstein

We have assembled accurate abundance data for Li, C, and N as well as the 12C/13C ratio for five field giants with [Fe/H]=-0.6 including Arcturus and two stars in the globular cluster 47 Tuc. Using their very precise Mbol values obtained from HIPPARCOSparallaxes, we can place them into an evolutionary sequence. The sequence shows that the 12C/13C ratios rati

Stephen E. Zepf, Keith M. Ashman

We review the observed properties of globular cluster systems and their implications for models of galaxy formation. Observations show that globular clusters form in gas-rich mergers, and that bimodal metallicity distributions are common in the globular cluster systems of ellipticals, with the metal-poor population more extended than the metal-rich one. Thes

Jean-Pierre Lasota, Jean-Marie Hameury

We review various aspects of disk instability models. We discuss problems and difficulties and present ways that have been suggested to solve them.

Lex Kaper

The International Ultraviolet Explorer satellite has made a tremendous contribution to the study of hot-star winds. Its long lifetime has resulted in the collection of ultraviolet spectra for a large sample of OB stars. Its unique monitoring capability has enabled detailed time-series analyses to investigate the stellar-wind variability for individual object

Daniel J. Eisenstein, Piet Hut

We describe a new method (HOP) for identifying groups of particles in N-body simulations. Having assigned to every particle an estimate of its local density, we associate each particle with the densest of the N_hop particles nearest to it. Repeating this process allows us to trace a path, within the particle set itself, from each particle in the direction of

Spencer Bloch, Andrei Okounkov

We study the character of the infinite wedge projective representation of the algebra of differential operators on the circle. We prove quasi-modularity of this character and also compute certain generating functions for traces of differential operators which we call correlation functions. These correlation functions are sums of determinants built from genus

Martin White, John E. Carlstrom, Mark Dragovan, William L. Holzapfel

We present a formalism for analyzing interferometric observations of Cosmic Microwave Background (CMB) anisotropy and polarization data. The formalism is based upon the ell-space expansion of the angular power spectrum favoured in recent years. Explicit discussions of maximum likelihood analysis, power spectrum reconstruction, parameter estimation, imaging a

Jean Alexandre, Vincenzo Branchina, Janos Polonyi

The motivation and the challenge in applying the renormalization group for systems with several scaling regimes is briefly outlined. The four dimensional $ϕ^4$ model serves as an example where a nontrivial low energy scaling regime is identified in the vicinity of the spinodal instability region. It is pointed out that the effective theory defined in the vic

I Dornic, C Godreche

We investigate the statistics of the mean magnetisation, of its large deviations and persistent large deviations in simple coarsening systems. We consider more specifically the case of the diffusion equation, of the Ising chain at zero temperature and of the two dimensional voter model. For the diffusion equation, at large times, the mean magnetisation has a

Michael B. Green, David Kutasov

A compactification of the heterotic string is considered which describes a particle propagating in the symmetric space M = SO(9,1;Z)\SO(9,1;R)/SO(9;R) in interaction with excited states whose dynamics is (1+1)-dimensional. The model appears to describe D-particle dynamics in type IIA string theory on M.

Colin J. Morningstar, J. Shigemitsu

The temporal component of the heavy-light axial vector current is constructed to one-loop order in perturbation theory and to order 1/M, where M is the heavy quark mass, in terms of operators suitable for use in lattice simulations of B and D mesons. The O(a)-improved clover action is used for the massless light quark, where a is the lattice spacing, and pro

Jayashree Balakrishna, Hisa-aki Shinkai

We study the dynamics of a self-gravitating scalar field solitonic object (boson star) in the Jordan-Brans-Dicke (BD) theory of gravity. We show dynamical processes of this system such as (i) black hole formation of perturbed equilibrium configuration on an unstable branch; (ii) migration of perturbed equilibrium configuration from the unstable branch to sta

Jay A. Frogel, Patricia A. Whitelock

We derive the frequency of occurrence of luminous long period variables (LLPVs) in globular clusters and in the Baade's Window field of the Galactic bulge. LLPVs occur only in clusters with [Fe/H]>/= -1.0. In these clusters their frequency of occurrence relative to the number of giant stars appears to be independent of metallicity. Integrated over all metall

Amihay Hanany, Alberto Zaffaroni

We consider configurations of six-branes, five-branes and eight-branes in various superstring backgrounds. These configurations give rise to $(0,1)$ supersymmetric theories in six dimensions. The condition for RR charge conservation of a brane configuration translates to the condition that the corresponding field theory is anomaly-free. Sets of infinitely ma

Prabhakar Pradhan, N. Kumar

Geometric phase shift associated with an electron propagating through a dimerized-disordered continuum is shown to be 0, or $\pm π$ (modulo 2$π$), according as the associated circuit traversed in the two-dimensional parameter space excludes, or encircles a certain singularity. This phase-shift is a topological invariant. Its discontinuous dependence on the e

Ashok Das, Gerald Dunne

We examine finite temperature perturbation theory for Chern-Simons theories, in the context of an analogue 0+1-dimensional model. In particular, we show how nonextensive terms arise in the perturbative finite temperature effective action, using both the real-time and imaginary-time formalisms. We illustrate how large gauge invariance is restored at all order

Jay A. Frogel

Extinction coefficients and sensitivity values in the JHKL band-passes measured on nearly 200 nights of observing between 1978 and 1992 on the 1.5-meter and the Blanco 4- meter telescopes at Cerro Tololo Inter-American Observatory are presented and discussed. Analysis of these data shows the following: There are seasonal variations in both the extinction coe

Ilka Brunner, Andreas Karch

We reconstruct non-trivial 6d theories obtained by Blum and Intriligator by considering IIB or SO(32) 5 branes at ALE spaces in the language of Hanany Witten setups. Using ST duality we make the equivalence of the two approaches manifest, thereby uncovering several new T-duality relations between the group theoretic data describing the embedding of the insta

Lauro Moscardini, Peter Coles, Francesco Lucchin, Sabino Matarrese

We discuss the theoretical interpretation of observational data concerning the clustering of galaxies at high redshifts. Building on the theoretical machinery developed by Matarrese et al. (1997), we make detailed quantitative predictions of galaxy clustering statistics for a variety of cosmological models, taking into account differences in spatial geometry

P. Castoldi, R. Escribano, J. M. Frere

Central pseudoscalar production in $pp$ scattering is suppressed at small values of $Q_\perp$, where $Q$ is defined as the difference between the momenta transferred from the two protons. Such a behaviour is expected if the production occurs through the fusion of two vectors. Photon exchange could provide the dominant contribution at low transferred momenta,

Joao Pulido

The data from solar neutrino experiments together with standard solar model predictions are used in order to derive the possible profile of the magnetic field inside the Sun, assuming the existence of a sizeable neutrino magnetic moment and the resonant spin flavour mechanism. The procedure is based on the relationship between resonance location and the ener

E. Gedalin, A. Moalem, L. Razdolskaja

A relativistic covariant one boson exchange model, previously applied to describe elastic nucleon-nucleon scattering, is extended to study $η$ production in NN collisions. The transition amplitude for the elementary BN->$η$N process with B being the meson exchanged (B=$π$, $|sigma$,$η$, $ρ$, $ω$ and $δ$) are taken to be the sum of four terms corresponding to

P. Stachura

The construction of Lie bialgebra from double Lie algebra is presented. It is used to relate some types of cobracket on inhomogenous so(p,q) algebras with double Lie algebra structures on so(p+1,q) or so(p,q+1). Also it is shown that the cobracket corresponding to kappa-deformation gives rise to complete Poisson-Lie Euclidean groups and non-complete Poincare

Ziv Hermon, Shay Caspi, Eshel Ben-Jacob

We present a novel electromagnetic model of DNA molecules, in which the P-bonds act as tunnel junctions and the H-bonds as capacitors. Excess charge in the model gives rise to two coupled modified sine-Gordon equations, which admit topological solitonic excitations. We study the dynamics of the solitons, their effect on the DNA transport properties, and comm

Alexander L. Frenkel, Keshavamurthy Indireshkumar

Wavy film flow of incompressible Newtonian fluid down an inclined plane is considered. The question is posed as to the parametric conditions under which the description of evolution can be approximately reduced for all time to a single evolution equation for the film thickness. An unconventional perturbation approach yields the most general evolution equatio

F. Grassi

In order to actually see the hadron-quark transition happening in a neutron star, we point out and study two static conditions (the transition hadronic density must be lower than the neutron star maximum hadronic density; the neutron star mass at the transition hadronic density must be in the observed range, of order 1.4 solar mass) and one dynamical conditi

F. Grassi, O. Socolowski

We show that a hadron gas model with continuous particle emission instead of freeze out may solve some of the problems (high values of the freeze out density and specific net charge) that one encounters in the latter case when studying strange particle ratios such as those by WA85. This underlines the necessity to understand better particle emission in hydro

Y. B. He, J. Hüfner, S. P. Klevansky, P. Rehberg

We study $ππ$ scattering in the I=1, $J^P=1^-$ channel at finite temperature in the framework of the extended Nambu-Jona-Lasinio model that explicitly includes vector and axial-vector degrees of freedom in addition to the usual scalar and pseudoscalar sector. The S-matrix in the coupled channels $q\bar q$ and $ππ$ is constructed via $ρ$-exchange in the $s$-c

Menachem Kojman, Saharon Shelah

We show that the assumption lambda > kappa^+ in the Trichotomy Theorem cannot be relaxed to lambda > kappa .

Saharon Shelah, Juris Steprāns

The Mycielski ideal M_k is defined to consist of all sets A subseteq k^omega such that {f restriction X: f in A} not= k^X for all X in [omega]^{aleph_0}. It will be shown that the covering numbers for these ideals are all equal. However, the covering numbers of the closely associated Roslanowski ideals will be shown to be consistently different.

Oren Kolman, Saharon Shelah

We show that the set of injective functions from any uncountable cardinal less than the continuum into the real numbers is of second category in the box product topology.

Aleksander Błaszczyk, Saharon Shelah

It is shown that there exists a complete, atomless, sigma-centered Boolean algebra, which does not contain any regular countable subalgebra if and only if there exist a nowhere dense ultrafilter. Therefore the existence of such algebras is undecidable in ZFC.

Saharon Shelah

We prove in ZFC that for mu >= aleph_2 there is a sigma --ideal I on mu and a Boolean sigma --subalgebra B of the family of subsets of mu which includes I such that the natural homomorphism from B onto B/I cannot be lifted.

Saharon Shelah

We present reasons for developing a theory of forcing notions which satisfy the properness demand for countable models which are not necessarily elementary submodels of some (H(chi), in). This leads to forcing notions which are ``reasonably&#39;&#39; definable. We present two specific properties materializing this intuition: nep (non-elementary properness) a

Saharon Shelah

We prove for any mu = mu^{< mu}< theta < lambda, lambda large enough (just strongly inaccessible Mahlo) the consistency of 2^mu = lambda-> [theta]^2_3 and even 2^mu = lambda-> [theta]^2_{sigma,2} for sigma < mu . The new point is that possibly theta > mu^+ .

Richard Beals, D. H. Sattinger

Using the scattering transform for $n^{th}$ order linear scalar operators, the Poisson bracket found by Gel&#39;fand and Dikii, which generalizes the Gardner Poisson bracket for the KdV hierarchy, is computed on the scattering side. Action-angle variables are then constructed. Using this, complete integrability is demonstrated in the strong sense. Real actio

R. Beals, D. H. Sattinger

The question of complete integrability of evolution equations associated to $n\times n$ first order isospectral operators is investigated using the inverse scattering method. It is shown that for $n>2$, e.g. for the three-wave interaction, additional (nonlinear) pointwise flows are necessary for the assertion of complete integrability. Their existence is dem

Nicolau C. Saldanha, Carlos Tomei

We compute the spectra of the adjacency matrices of the semi-regular polytopes. A few different techniques are employed: the most sophisticated, which relates the 1-skeleton of the polytope to a Cayley graph, is based on methods akin to those of Lovász and Babai ([L], [B]). It turns out that the algebraic degree of the eigenvalues is at most 5, achieved at t

Klaus Behrndt, Ilka Brunner

Like the M-theory itself also the worldvolume theory of the M5-brane contains brane excitations, which can be extracted from the supersymmetry algebra. Bound states (intersecting branes) of the worldvolume can be translated into bound states of {11-d} SUGRA. In this paper, we discuss the matrix description for these bound states and their entropy (=degenerac

Carlo Angelantonj

We review the construction of open descendants of the type IIB superstring on the Z-orbifold. It results in a chiral four-dimensional model with gauge group $SO(8) \otimes U(12)$ and three generations of matter in the $(8,12^*)\oplus (1,66)$ representations. As a test of type I - heterotic duality, that reduces to a weak/weak duality in D=4, a heterotic mode

P. M. Ferreira, J. A. Gracey

We solve the Schwinger Dyson equations of the O(N) symmetric Wess-Zumino model at O(1/N^3) at the non-trivial fixed point of the d-dimensional beta-function and deduce a critical exponent for the wave function renormalization at this order. By developing the epsilon-expansion of the result, which agrees with known perturbation theory, we examine the distribu

J. M. F. Labastida, Esther Perez

We construct gauge invariant operators for singular knots in the context of Chern-Simons gauge theory. These new operators provide polynomial invariants and Vassiliev invariants for singular knots. As an application we present the form of the Kontsevich integral for the case of singular knots.

P. M. Ferreira, J. A. Gracey

We extend the critical point self-consistency method used to solve field theories at their d-dimensional fixed point in the large N expansion to include superfields. As an application we compute the beta-function of the Wess-Zumino model with an O(N) symmetry to O(1/N^2). This result is then used to study the effect the higher order corrections have on the r

Silvia Penati, Daniela Zanon

We consider the coupling of nonminimal scalar multiplets to supersymmetric Yang-Mills in four dimensions and compute the one-loop contribution to the low-energy effective action in the abelian sector. We show that the resulting theory realizes the dual version of the corresponding one from N=2 supersymmetric Yang-Mills.

E. Alvarez, P. Meessen

A Newtonian matrix cosmology, correspoding to the BFSS model of eleven-dimensional M-theory in the IMF as a (0+1) M(atrix) model is constructed. Interesting new results are obtained, such as the existence of (much sought for in the past) static solutions. The possible interpretation of the off-diagonal entries as a background geometry is also briefly discuss

J. L. F. Barbon, A. Pasquinucci

We discuss the role of D0-branes as instantons in the construction of SU(N) Super Yang-Mills and Super QCD theories in four space-time dimensions with D4-, D6- and NS-branes. [To appear in the proceedings of the conference &#34;Quantum Aspects of Gauge Theories, Supersymmetry and Unification&#34;, held at Neuchatel University, Neuchatel, Switzerland, 18--23

D. K. Park, Sahng-Kyoon Yoo

Energy-dependent Green&#39;s functions for the two and three dimensional $δ$-function plus harmonic oscillator potential systems are derived by incorporating the renormalization and the self-adjoint extension into the Green&#39;s function formalism, respectively. It is shown that both methods yield an identical Green&#39;s function if a certain relation betw

M. B. Halpern, C. Schwartz

We introduce a complete set of gauge-invariant variables and a generalized Born-Oppenheimer formulation to search for normalizable zero-energy asymptotic solutions of the Schrodinger equation of SU(2) matrix theory. The asymptotic method gives only ground state candidates, which must be further tested for global stability. Our results include a set of such g

Bert Schroer

The recently proposed constructive approach to nonperturbative QFT, based on modular localization, is reviewed and extended. It allows to unify black holes physics and H-temperatures (H standing for Hawking or Horizon) with the bootstrap-formfactor program for nonperturbative construction of low dimensional QFT. In case of on-shell particle number conservati

A. B. Balantekin, J. F. Beacom, J. M. Fetter

We introduce simple analytic expressions for the neutrino survival probability in media valid in the quasi-adiabatic limit. These expressions provide a quick but accurate alternative to numerical solution of the neutrino propagation equations for the Mikheyev-Smirnov-Wolfenstein effect. They can also be used to extract information about the density scale hei

Andrei Afanasev, Philip R. Page

We estimate the kinematic dependence of the exclusive photo-- and electroproduction of $J^{PC}=1^{-+}$ exotic mesons due to $π$ exchange. We show that the kinematic dependence is largely independent of the exotic meson form factor, which is explicitly derived for a $1^{-+}$ isovector hybrid meson in the flux-tube model of Isgur and Paton. The relevance to ex

Stephan Narison

I study (for the first time) the dependence of M_D and of the leptonic decay constant f_D on the variation of the running charm quark mass m_c(ν). I conclude that the present data on f_{D_s} from D_s into μνdecay give a weaker constraint than M_D, where the latter leads to the result, m_c(M_c)=(1.08\pm 0.11) GeV, to two-loop accuracy in the {MS}-bar scheme,

Zoltan Nagy, Zoltan Trocsanyi

We present the next-to-leading order perturbative QCD prediction to the four-jet angular distributions used by experimental collaborations at LEP for measuring the QCD color charge factors. We compare our results to ALEPH data corrected to parton level. We perform a leading order ``measurement&#39;&#39; of the QCD color factor ratios by fitting the leading o

Maria-Teresa Dova, John Swain, Lucas Taylor

The leptonic branching fractions of the tau lepton are sensitive to anomalous charged current interactions. We use recent experimental measurements to determine the weak charged current magnetic and electric dipole moments and the Michel parameter $η$ with unprecedented precision. These results are then used to constrain the tau compositeness scale and the a

John Swain, Lucas Taylor

We present new constraints on the mass $m_{ν_τ}$ of the tau neutrino and its mixing with a fourth generation neutrino. From an analysis of the partial widths of tau lepton decays we obtain the following bounds at the 90% confidence level: $m_{ν_τ} < 32$ MeV and $\sin^2θ< 0.007$, where $θ$ describes the Cabibbo-like mixing of the third and fourth generation n

I. Akushevich, A. B. Arbuzov, E. A. Kuraev

The matrix element squared for Compton scattering of a heavy photon on a longitudinally polarized electron is calculated. The gauge-invariant tensor structure of the heavy photon polarization is considered, assuming that all kinematical invariants and the invariant mass of the heavy photon are large compared with the electron mass. The expressions for the Bo

H. Päs

Neutrinoless double beta decay ($0νββ$) is one of the most sensitive approaches to test particle physics beyond the standard model. During the last years, besides the most restrictive limit on the effective Majorana neutrino mass, the analysis of new contributions by the Heidelberg group led to bounds on left-right-symmetric models, leptoquarks and R-parity

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

The CP violating electric and weak dipole moment form factors of the top quark, $\dgs$ and $\dzs$, appear in the process \mbox{$e^{+}e^{-} \to t \bar{t}$}. We present a complete analysis of these dipole moment formfactors within the Minimal Supersymmetric Standard Model with complex parameters. We include gluino, chargino, and neutralino exchange in the loop

Michihiro Hori, Yuichiro Kiyo, Takashi Nasuno

We analyze the spin correlations of the top quark pairs produced at Photon Linear Colliders. We employ the circular polarized photon beams and general spin basis for the top quark pair. We consider general spin bases to find a strong spin correlation between produced top quark and anti-top quark. We show the cross-section in these bases and discuss the chara

K. Zuber

The current status of neutrino oscillation searches with reactors and accelerators is reviewed. An outlook, especially on future long baseline neutrino oscillation projects, is given.

S. A. Smolyansky, G. Roepke, S. Schmidt, D. Blaschke

A quantum kinetic equation has been derived for the description of pair production in a time-dependent homogeneous electric field $E(t)$. As a source term, the Schwinger mechanism for particle creation is incorporated. Possible particle production due to collisions and collisional damping are neglected. The main result is a closed kinetic equation of the non

Yue-Liang Wu

Symmetries concerning the ordinary coordinate spacetime and internal spacetime are discussed. A possible unification model of electroweak, strong and gravitational interactions is briefly described.

Uma Mahanta

In this article we study the effect of Hg contact interaction on H production by gluon fusion at at a hadron collider. Two such d=6 operators have been considered. The present precision for measuring α_s implies a lower bound of around 2 Tev on the scale for the CP even operator O_1. On the other hand the precision for measuring d_n implies a lower bound of

ZEUS Collaboration

Photon diffractive dissociation, $γp \to Xp$, has been studied at HERA with the ZEUS detector using $ep$ interactions where the virtuality $Q^2$ of the exchanged photon is smaller than 0.02 GeV$^2$. The squared four-momentum $t$ exchanged at the proton vertex was determined in the range $0.073<|t|<0.40$ GeV$^2$ by measuring the scattered proton in the ZEUS L

Wu Zhong Chao

In the No-Boundary Universe a primordial black hole is created from a constrained gravitational instanton. The black hole created is immersed in the de Sitter background with a positive cosmological constant. The constrained instanton is characterized not only by the external parameters, the mass parameter, charge and angular momentum, but also by one more i

Jayashree Balakrishna, Edward Seidel, Wai-Mo Suen

The dynamical evolution of self-gravitating scalar field configurations in numerical relativity is studied. The previous analysis on ground state boson stars of non-interacting fields is extended to excited states and to fields with self couplings. Self couplings can significantly change the physical dimensions of boson stars, making them much more astrophys

Frank Gronwald, Uwe Muench, Alfredo Macías, Friedrich W. Hehl

Starting with a `bare&#39; 4-dimensional differential manifold as a model of spacetime, we discuss the options one has for defining a volume element which can be used for physical theories. We show that one has to prescribe a scalar density σ. Whereas conventionally \sqrt{|\det g_{ij}|} is used for that purpose, with g_{ij} as the components of the metric, w

Franca Manghi, Massimo Rontani

We present the results of a recently developed approach where the interplay between the itinerant and localized character of electrons in narrow band materials is described by adding on-site correlation effects to a first principle band calculation: the single particle band states are treated as mean field solutions of a multi-orbital Hubbard Hamiltonian and

Joachim Jacobsen, James P. Sethna

The homoepitaxial growth of initially flat surfaces has so far always led to surfaces which become rougher and rougher as the number of layers increases: even in systems exhibiting ``layer by layer&#39;&#39; growth the registry of the layers is gradually lost. We propose that pulsed glancing-angle sputtering, once per monolayer, can in principle lead to laye

Silvia Kuva, Osame Kinouchi, Nestor Caticha

We study the problem of determining the Hamiltonian of a fully connected Ising Spin Glass of $N$ units from a set of measurements, whose sizes needs to be ${\cal O}(N^2)$ bits. The student-teacher scenario, used to study learning in feed-forward neural networks, is here extended to spin systems with arbitrary couplings. The set of measurements consists of da

L. De Santis, R. Resta

In practical implementations of density-functional theory, the only term where an orbital description is needed is the kinetic one. Even this term in principle depends on the density only, but its explicit form is unknown. We provide a novel solution of the N-representability problem for an extended system, which implies an explicit form for the Kohn-Sham ki

S. V. Shulga, S. -L. Drechsler, G. Fuchs, K. -H. Mueller

We present new upper critical field Hc2(T) data in a broad temperature region from 0.3K to Tc for LuNi2B2C and YNi2B2C single crystals with well characterized low impurity scattering rates. The absolute values for all T, in particular Hc2(0), and the sizeable positive curvature (PC) of Hc2(T) at high and intermediate T are explained quantitatively within an

Michael R. Geller, Carlos Wexler, David J. Thouless

The total transverse force acting on a quantized vortex in a type-II superconductor determines the Hall response in the mixed state, yet a consensus as to its correct form is still lacking. In this paper we present an essentially exact expression for this force, valid in the superclean limit, which was obtained by generalizing the recent work by Thouless, Ao

C. Monthus, O. Golinelli, Th. Jolicoeur

We formulate a real-space renormalization scheme that allows the study of the effects of bond randomness in the Heisenberg antiferromagnetic spin-1 chain. There are four types of bonds that appear during the renormalization flow. We implement numerically the decimation procedure. We give a detailed study of the probability distributions of all these bonds in

D. E. Steinhauer, C. P. Vlahacos, S. K. Dutta, B. J. Feenstra

We describe quantitative imaging of the sheet resistance of metallic thin films by monitoring frequency shift and quality factor in a resonant scanning near-field microwave microscope. This technique allows fast acquisition of images at approximately 10 ms per pixel over a frequency range from 0.1 to 50 GHz. In its current configuration, the system can resol

V. Pasquier, F. D. M. Haldane

We consider the problem of Bosonic particles interacting repulsively in a strong magnetic field at the filling factor $ν=1$. We project the system in the Lowest Landau Level and set up a formalism to map the dynamics into an interacting Fermion system. Within a mean field approximation we find that the composite Fermions behave as a gas of neutral dipoles an

O. Heinonen, J. M. Kinaret, M. D. Johnson

We extend our ensemble density functional approach to quantum Hall systems to include non-collinear spins to study charge-spin textures in inhomogeneous quantum Hall systems. We have studied the edge reconstruction in quantum dots at unit bulk filling factor and at 1/3 bulk filling factor as a function of the stiffness of an external confining potential. For