November 1995 arXiv papers — page 10

Bob Mann, Will Saunders, Andy Taylor

We use a series of statistical techniques to compare the clustering of samples of IRAS galaxies selected on the basis of their far-infrared emission temperature, to see whether a temperature-dependent effect, such as might be produced by interaction-induced star formation, could be responsible for the increase in clustering strength with redshift in the QDOT

I. A. Taimanov

Global deformations of surfaces, immersed into the Euclidean 3-space, by using the modified Novikov--Veselov equation are investigated. relation to the theory of the Willmore functional is discussed

Kingman Cheung

We study the effects of the anomalous chromoelectric and chromomagnetic dipole moments of the top quark on the top-pair production, on the top-pair plus 1jet production, and on their ratios, as well as their dependence on the transverse momenta of the top quark and the jet. We also construct CP-odd and $\hat T$-odd observables to probe the dispersive part of

S. Ambrosanio, M. Carena, B. Mele, C. E. M. Wagner

Within the minimal supersymmetric extension of the Standard Model, the best fit to the most recent precision-measurement data requires charginos and neutralinos, with dominant Higgsino components and with masses within the reach of LEP1.5 ($\sqrt{s}=140$ GeV). In this work, we present a detailed analysis of the neutralino and chargino production processes fo

R. J. Furnstahl, Xuemin Jin, Derek B. Leinweber

Two new QCD sum rules for nucleons in nuclear matter are obtained from a mixed correlator of spin-1/2 and spin-3/2 interpolating fields. These new sum rules, which are insensitive to the poorly known four-quark condensates, provide additional information on the nucleon scalar self-energy. These new sum rules are analyzed along with previous spin-1/2 interpol

Ya. V. Bazaikin

An infinite family of pairwise nonhomeomorphic 13-dimensional positively curved manifolds is constructed

J. Fuster, S. Marti

Recent results on the total production and angular distribution of charged particles originated from the fragmentation of quark and gluon jets are presented. Experimental studies of the multiplicity as a function of the quark and gluon jet energy, the inter-jet particle flow and the individual fragmentation fucntions are reviewed and compared to expectations

Kiyoshi Ezawa

It is known that Ashtekar's formulation for pure Einstein gravity can be cast into the form of a topological field theory, namely the $SU(2)$ BF theory, with the B-fields subject to an algebraic constraint. We extend this relation between Ashtekar's formalism and BF theories to $N=1$ and $N=2$ supergravities. The relevant gauge groups in these cases

Kazuo Ueda, Hiroshi Kontani, Manfred Sigrist, Patrick A. Lee

A theoretical model is presented to explain the spin gap observed for CaV$_4$O$_9$. The underlying lattice of the 1/5-depleted square lattice favors a formation of plaquette resonating valence bond state. Inclusion of the frustrating second neighbor interaction enhances this tendency, leading to a quantum disordered state of a two dimensional spin-1/2 Heisen

V. Antonelli, S. Bertolini, J. O. Eeg, M. Fabbrichesi

We use the chiral quark model to estimate the coefficients of the weak chiral lagrangian as obtained from the bosonization of the ten relevant operators of the $ΔS = 1$ effective quark lagrangian. All contributions of order $N_c^2$ as well as $N_c$ and $α_s N_c$ are included. The chiral coefficients are given in terms of $f_π$, the quark and gluon condensate

C. Bachas

I calculate the semiclassical phase shift ($δ$), as function of impact parameter ($b$) and velocity ($v$), when one D-brane moves past another. From its low-velocity expansion I show that, for torroidal compactifications, the moduli space of two identical D-branes stays flat to all orders in $α^\prime$. For K3 compactifications, the calculation of the D-bran

Ariel O. Garcia, Roberto C. Trinchero

A derivation of the Lax pair for the (1+1)-dimensional non-linear sigma-model is described. Its main benefit is to have a clearer physical origin and to allow the study of a generalization to higher dimensions.

Atsushi Nagai, Junkichi Satsuma

Some of the well-known convergence acceleration algorithms, when viewed as two-variable difference equations, are equivalent to discrete soliton equations. It is shown that the $η-$algorithm is nothing but the discrete KdV equation. In addition, one generalized version of the $ρ-$algorithm is considered to be integrable discretization of the cylindrical KdV

Robert B. Griffiths, Chi-Sheng Niu

Shor's algorithms for factorization and discrete logarithms on a quantum computer employ Fourier transforms preceding a final measurement. It is shown that such a Fourier transform can be carried out in a semi-classical way in which a ``classical'' (macroscopic) signal resulting from the measurement of one bit (embodied in a two-state quantum sys

Ludger Hannibal

The acausal behavior of relativistic states exhibited by Hegerfeldt is shown not to be present in physical systems described by first order in time evolution equations.

B. Fernandez

We prove the existence and we study the stability of the kink-like fixed points in a simple Coupled Map Lattice for which the local dynamics has two stable fixed points. The condition for the existence allows us to define a critical value of the coupling parameter where a (multi) generalized saddle-node bifurcation occurs and destroys these solutions. An ext

Jun Hu, Charles Tresser

We show that in any family of stunted sawtooth maps, the set of maps whose set of periods is the set of all powers of 2 has no interior point, i.e., the combinatorial description of the boundary of chaos coincides with the topological description. We also show that, under mild assumptions, smooth multimodal maps whose set of periods is the set of all powers

R. Jackiw, So-Young Pi

We discuss the recently devised one-loop gap equation for the magnetic mass of hot QCD. An alternative, and one would hope equivalent, gap equation is presented, which however shows no mass generation at the one-loop level.

A. Sevrin

We review some aspects of gauged WZW models. By choosing a nilpotent subgroup as gauge group, one is lead to three main applications: the construction of field theories with an extended conformal symmetry, the construction of the effective action of (extended) 2D gravities and the systematic construction of string theories with some extended gauge symmetry.

E. Ragoucy, A. Sevrin, P. Sorba

We present an algebraic approach to string theory. An embedding of $sl(2|1)$ in a super Lie algebra together with a grading on the Lie algebra determines a nilpotent subalgebra of the super Lie algebra. Chirally gauging this subalgebra in the corresponding Wess-Zumino-Witten model, breaks the affine symmetry of the Wess-Zumino-Witten model to some extension

G. Lopes Cardoso, D. Lust, T. Mohaupt

In this paper we summarize our recent work about perturbative and non-perturbative effects in four-dimensional heterotic strings with $N=2$ space-time supersymmetry.

Sen-Ben Liao

We derive a manifestly gauge invariant low energy blocked action for Yang-Mills theory using operator cutoff regularization, a prescription which renders the theory finite with a regulating smearing function constructed for the proper-time integration. By embedding the momentum cutoff scales in the smearing function, operator cutoff formalism allows for a di

R. Brustein, B. A. Ovrut

We report on progress towards evaluation of stringy non-perturbative effects, using a two dimensional effective field theory for matrix models. We briefly discuss the relevance of such effects to models of dynamical supersymmetry breaking.

Masako Asano

We investigate the Chung-Fukuma-Shapere theory, or Kuperberg theory, of three-dimensional lattice topological field theory. We construct a functor which satisfies the Atiyah's axioms of topological quantum field theory by reformulating the theory as Turaev-Viro type state-sum theory on a triangulated manifold. The theory can also be extended to give a to

A. I. Davydychev, J. B. Tausk

Explicit general formulae for the tensor reduction of two-loop massive vacuum diagrams are presented. The problem of calculating the corresponding coefficients is shown to be equivalent to the problem of constructing differential operators (projectors) extracting the coefficients of the momentum expansion of massive scalar three-point functions (with any num

X. Y. Pham

Strictly within the standard electro-weak interaction, CP violation in the flavour conserving process $η\ra π+ π$ could originate from the mixing of the $η$ meson with the virtual scalar Higgs $ H^{0}$ via $ W^{+}+W^{-}$ and $Z^{0}+Z^{0}$ exchange. The parity-violation carried by these weak gauge bosons makes the mixing possible at two-loop level. Nowhere th

Werner Bernreuther, Peter Overmann

We consider, both for unpolarized and longitudinally polarized electron beams, the production of a top quark pair in e+e- collisions with subsequent semileptonic top and nonleptonic anti-top decay and vice versa and investigate optimized angular correlations which are sensitive to CP non-conservation in the top quark production vertex. We calculate these cor

Y. Hisamatsu, A. Niégawa

We calculate the energy and hydrostatic pressure densities of a hot quark-gluon plasma in thermal equilibrium through diagrammatic analyses of the statistical average, $\langle Θ_{μν} \rangle$, of the energy-momentum-tensor operator $Θ_{μν}$. To leading order at high temperature, the energy density of the long wave length modes is consistently extracted by a

Frank Cuypers

We review the pair-production and decay of selectrons in $e^-e^-$ collisions and show how the standard model backgrounds can be virtually eliminated with polarized beams. The exceedingly simple analysis involved and the large sample of background-free supersymmetric events make this linear collider operating mode ideal for discovering selectrons and measurin

Jean-Rene Cudell, Oscar F. Hernandez

Production of rare particles within rapidity gaps has been proposed as a background-free signal for the detection of new physics at hadron colliders. No complete formalism accounts for such processes yet. We study a simple lowest-order QCD model for their description. Concentrating on Higgs production, we show that the calculation of the cross section pp ->

Thomas Kalkreuter

Two numerical algorithms for the computation of eigenvalues of Dirac operators in lattice gauge theories are described: one is an accelerated conjugate gradient method, the other one a standard Lanczos method. Results obtained by Cullum's and Willoughby's variant of the Lanczos method (whose convergence behaviour is closely linked with the local spec

R. M. Woloshyn, F. X. Lee

Chiral symmetry breaking is calculated as a function of cooling in quenched lattice QCD. A non-zero signal is found for the chiral condensate beyond one hundred cooling steps, suggesting that there is chiral symmetry breaking associated with instantons. Quantitatively, the chiral condensate in cooled gauge field configurations is small compared to the value

Sören Holst

Barbero recently suggested a modification of Ashtekar's choice of canonical variables for general relativity. Although leading to a more complicated Hamiltonian constraint this modified version, in which the configuration variable still is a connection, has the advantage of being real. In this article we derive Barbero's Hamiltonian formulation from

E. N. Glass

When the Penrose-Goldberg (PG) superpotential is used to compute the angular momentum of an axial symmetry, the Killing potential $Q_{(φ)}^{μν}$ for that symmetry is needed. Killing potentials used in the PG superpotential must satisfy Penrose's equation. It is proved for the Schwarzschild and Kerr solutions that the Penrose equation does not admit a $%Q

Ye-lin Ou

We introduce the complete lifts of maps between (real and complex) Euclidean spaces and study their properties concerning holomorphicity, harmonicity and horizontal weakly conformality. As applications, we are able to use this concept to characterize holomorphic maps $ϕ:{\Bbb C}^{m}\supset U\longrightarrow {\Bbb C}^{n}$ (Proposition 2.3) and to construct man

Felix von Oppen, Tilo Wettig

It has recently been established that a short-range interaction can strongly delocalize a pair of particles moving in a disordered potential. We investigate whether an analogous effect exists also for pairs of quasiparticles in the Anderson insulator by employing an approximate numerical evaluation of the two-particle Green function of the many-body system.

Andreas Schadschneider, Michael Schreckenberg

We use analytical methods to investigate cellular automata for traffic flow. Two different mean-field approaches are presented, which we call site-oriented and car-oriented, respectively. The car-oriented mean-field theory yields the exact fundamental diagram for the model with maximum velocity $\vm =1$ whereas in the site-oriented approach one has to take i

E. P. Raposo, M. D. Coutinho-Filho, F. C. Montenegro

The influence of a frustrated bond on the magnetic properties of a d=3 uniaxial (Ising) b.c.c. diluted antiferromagnet, with emphasis in the compound $Fe_{x}Zn_{1-x}F_{2}$, is investigated by a local mean-field numerical simulation. In particular we find that the initial drop of the saturation staggered magnetization ($M_{S}$) with concentration follows a pe

Yoshihiro Nishiyama, Masuo Suzuki

The ground state and excitation spectra of the $S=1$ Heisenberg spin chain with hole hopping are investigated by means of the numerical-diagonalization method and by the help of the Zhang-Arovas picture. As for the charge sector, two phases are found. It is shown that in the weak-hopping region, a phase separation occurs, while in the strong-hopping region,

Andreas Giesekus, Uwe Brandt

We study a class of exactly solvable models for strongly correlated electrons, defined on a set of N cells, and with infinite on-site repulsion on part of the sites of each cell. For 2N or more electrons the exact ground state is known. We construct a tractable (2N-1)-particle state which becomes asymptotically degenerate to the ground state in the thermodyn

Tom Theuns

The energy diffusion coefficients D_n(E) (n=1,2) for a system of equal mass particles moving self-consistently in an N-body realisation of a King model are computed from the probability per unit time, P(E, Delta E), that a star with initial energy E will undergo an energy change Delta E. In turn, P is computed from the number of times during the simulation t

M. Catelan, J. A. de Freitas Pacheco

Morphological aspects of the $V, \bv$ diagram of metal-rich globular clusters are analyzed, on the basis of stellar evolution models for horizontal-branch (HB) and red giant branch stars. These have been incorporated into detailed synthetic HB models, the influence of differential reddening upon which is also discussed. The synthetic HB models are found to b

Rosa A. Gonzalez, James R. Graham

We present optical and IR surface photometry of M99 (NGC 4254) at g, r_S i, J and K'. We also present a K' image of M51 (NGC 5194) for comparison. Fourier decomposition of the disk light reveals that the radial distribution of power depends on wavelength, which in turn implies that the spiral structure traced in the visual (i.e. young population I and dust)

Gerard Laumon

Drinfeld a associe a tout systeme local irreductible de rang 2 sur une surface de Riemann compacte un "faisceau automorphe". Ce faisceau automorphe vit sur l'espace de modules des fibres vectoriels de rang 2 sur cette meme surface de Riemann. En fait, Drinfeld a donne deux constructions de ce faisceau automorphe. La premiere est basee sur l'e

Jorma Louko, Rafael D. Sorkin

We investigate topology change in (1+1) dimensions by analyzing the scalar-curvature action $1/2 \int R dV$ at the points of metric-degeneration that (with minor exceptions) any nontrivial Lorentzian cobordism necessarily possesses. In two dimensions any cobordism can be built up as a combination of only two elementary types, the ``yarmulke'' and the

Dan-di Wu

Assuming the small entries in the mass matrices are produced by fermion-scalar loops, we calculate the anomalous dipole moments of the leptons and quarks. The top quark appears in all the loops as the mass seed. When comparing the results with experimental data, including electric and magnetic dipole moments, and radiative transition rates, we obtain the mas

Erik Sorensen, Ian Affleck

A scaling form for the local susceptibility, derived from renormalization group arguments, is proposed. The scale over which the uniform part of this scaling form varies can be viewed as a definition of the Kondo ``screening cloud" $\sim ξ_K$. The proposed scaling form interpolates between Ruderman-Kittel-Kasuya-Yosida (RKKY) results in the high temperat

Rufus S. Hamade, James H. Horne, John M. Stewart

We study the spherically symmetric collapse of the axion/dilaton system coupled to gravity. We show numerically that the critical solution at the threshold of black hole formation is continuously self-similar. Numerical and analytical arguments both demonstrate that the mass scaling away from criticality has a critical exponent of $γ= 0.264$.

Janusz Rosiek

This erratum contains the full corrected version of the paper {\em Complete set of Feynman rules for the Minimal Supersymmetric Standard Model}, published in Phys. Rev. D41 (3464) 1990. The complete set of Feynman rules for the R-parity conserving MSSM is listed, including the most general form of flavour mixing. Propagators and vertices are computed in t&#3

Mustapha Azreg-Ainou

Kaluza-Klein theory is a 5-dimensional Einstein general relativity; it has the interest of describing on an equal footing the laws of gravitation and electromagnetism in a geometrically unified way. We present it in Chapter 1, and we generalize it by adding to the equations of the theory the Lanczos tensor (endowed with the same physical properties as the Ei

Marc Albrecht, Frederic Mila

We study the stability of the 4-site plaquette order in a model recently introduced by Katoh and Imada to explain the spin gap in CaV4O9. We show that all relevant types of order can be described within the framework of Schwinger boson mean fiel theory, and we make predictions regarding their relative stability. The results are compared to exact diagonalisat

Matej Pavsic

We consider a theory in which spacetime is an n-dimensional surface $V_n$ embedded in an $N$-dimensional space $V_N$. In order to enable also the Kaluza-Klein approach we admit $n > 4$. The dynamics is given by the minimal surface action in a curved embedding space. The latter is taken, in our specific model, as being a conformally flat space. In the quantiz

S. A. Gurvitz, Ya. S. Prager

It is shown that under certain conditions the resonant transport in mesoscopic systems can be described by modified (quantum) rate equations, which resemble the optical Bloch equations with some additional terms. Detailed microscopic derivation from the many-body Schrödinger equation is presented. Special attention is paid to the Coulomb blockade and quantum

Yakir Aharonov, Lev Vaidman

``Weak'', ``protective'', and ``delayed observation'' measurements are analyzed in the framework of the Bohm interpretation of quantum theory. It is argued that the above varieties of measurements manifest some difficulties of the Bohm interpretation since they show that Bohmian trajectories behave not as we would expect from a classi

Edward Frenkel

We define hierarchies of differential--q-difference equations, which are q-deformations of the equations of the generalized KdV hierarchies. We show that these hierarchies are bihamiltonian, one of the hamiltonian structures being that of the q-deformed classical W-algebra of sl(N), defined by Reshetikhin and the author. We also find q-deformations of the mK

A. N. Antonov, S. S. Dimitrova, M. K. Gaidarov, M. V. Stoitsov

A phenomenological method based on the natural orbital representation is applied to construct the ground state one-body density matrix which describes correctly both density and momentum distributions in $^{4}He$, $^{16}O$ and $^{40}Ca$ nuclei. The parameters of the matrix are fixed by a best fit to the experimental density distribution and to the correlated

M. Temple-Raston

A generalisation to electrodynamics and Yang-Mills theory is presented that permits computation of the speed of light. The model presented herewithin indicates that the speed of light in vacuo is not a universal constant. This may be relevant to the current debate in astronomy over large values of the Hubble constant obtained through the use of the latest ge

Paul Mansfield, Jiannis Pachos

For fields that vary slowly on the scale of the lightest mass the logarithm of the vacuum functional of a massive quantum field theory can be expanded in terms of local functionals satisfying a form of the Schrödinger equation, the principal ingredient of which is a regulated functional Laplacian. We construct to leading order a Laplacian for the O(N) sigma-

Terry Gannon

In this paper we explicitly classify all modular invariant partition functions for su(n) at level 2 and 3. Previously, these were known only for level 1. The level 2 exceptionals exist at n=10, 16, and 28; the level 3 exceptionals exist at n=5, 9, and 21. One of these is new, but the others were all anticipated by the "rank-level duality" relating su

I. Kanatchikov

We review the recent generalization of the basic structures of classical analytical mechanics to field theory within the framework of the De Donder-Weyl (DW) covariant canonical theory. We start from the Poincaré-Cartan form and construct the analogue of the symplectic form -- the polysymplectic form of degree n+1, where n is the dimension of the space-time.

George Thompson

These are the lecture notes of a set of lectures delivered at the 1995 Trieste summer school in June. I review some recent work on duality in four dimensional Maxwell theory on arbitrary four manifolds, as well as a new set of topological invariants known as the Seiberg-Witten invariants. Much of the necessary background material is given, including a crash

J. M. F. Labastida

A brief introduction to Topological Quantum Field Theory as well as a description of recent progress made in the field is presented. I concentrate mainly on the connection between Chern-Simons gauge theory and Vassiliev invariants, and Donaldson theory and its generalizations and Seiberg-Witten invariants. Emphasis is made on the usefulness of these relation

Jean-Pierre Derendinger

An effective lagrangian analysis of gaugino condensation is performed in a supersymmetric gauge theory with field-dependent gauge couplings described with a linear multiplet. An original aspect of this effective lagrangian is the use of a real vector superfield to describe composite gauge invariant degrees of freedom. The duality equivalence of this approach

Y. Sumino

We present a new method for calculating the Green functions for a lattice scalar field theory in $D$ dimensions with arbitrary potential $V(ϕ)$. The method for non-perturbative evaluation of Green functions for $D \! = \! 1$ is generalized to higher dimensions. We define ``hole functions'' $A^{(i)}~(i=0,1,2,\cdots,N \! -\! 1)$ from which one can cons

Rolf Tarrach

We critically analyze the introduction of an independent zero momentum mode field renormalization for Phi4. It leads to an infrared divergent effective action. It does not achieve its purpose: triviality still gives massless particles in the broken phase in the continuum limit. It leads to an effective potential which is not the low energy limit of the effec

Taichiro Kugo

The ratio Z_1/Z_3 of vertex and wave-function renormalization factors, which is universal (i.e., matter-independent), is shown to equal 1+u which gives the residue of the scalar pole $\propto p_μp_ν/p^2$ of 2-point function < D_μc D_ν\bar c >. This relation is interesting since 1+u=0 has been known to give a sufficient condition for color confinement. We als

A. Astashkevich

In the paper we present a different proof of the theorem of B. L. Feigin and D. B. Fuchs about the structure of Verma modules over Virasoro algebra. We state some new results about the structure of Verma modules over Neveu-Schwarz. The proof has thwo advantages: first, it is simplier in the most interesting cases (for example in the so called minimal models)

Gottfried Holzwarth

This lecture comprises some recent developments concerning the description of baryons as topological solitons in effective chiral meson theories. In the first part one-loop corrections to the classical tree approximation are discussed. This involves renormalization of low-energy coupling constants and evaluation of the finite next-to-leading-order terms in t

Laura Reina

In the contest of a Two Higgs Doublet Model without flavor conservation, the presence of Flavor Changing Neutral Scalar Currents may affect in particular the couplings of the top quark. Some ideas on how to look for new signals from Flavor Changing Interactions at the next generation of lepton colliders are presented.

David Persson

Using the general form of the static energy solutions to the Dirac equation with a magnetic field, we calculate a general self-energy matrix in the Furry-picture. In the limit of high temperatures, but even higher magnetic fields, a self-consistent dispersion relation is solved. In contrast to the high temperature limit, this merely results in a small mass s

N. I. Kochelev

It is shown, that specific properties of the instanton induced interaction between quarks leads to the anomalous violation of the OZI-rule in the $N\bar N\to ΦΦ$, $N\bar N\to Φγ$ reactions. In the framework of instanton model of the QCD vacuum, the energy dependence of the cross sections of these reactions is calculated.

V. M. Aquino, J. Bellandi, M. M. Guzzo

We find exact analytical expressions for mixing angles in matter in the context of three generation neutrino oscillations in matter to discuss the role of resonances in this phenomenon. We show that some knowledge from conventional two neutrino MSW effect, which has been extended to approximated solutions to three neutrino oscillations, has to be abandoned i

A. Dobado, J. Morales

In this work we present the results of a complete calculation of the $γ γ\rightarrow π^0π^0$ amplitude to leading order in the large $N$ approximation ($N$ being the number of Goldstone bosons) up to order $m^2_π/F^2$. The amplitude turns to be proportional to that of $π^+π^-\rightarrow π^0π^0$. In spite of the fact that this factorization property cannot ho

J. Polonyi

The haaron gas description is reviewed for the QCD vacuum. The role of non-renormalizable operators is emphasised in the mechanism which generates the string tension. Additional examples are mentioned where certain non-renormalizable operators of the bare lagrangian turn out to be important at finite energy scale.

P. H. Damgaard, J. Greensite, M. Hasenbusch

The behavior of static sources transforming according to different irreducible representations of the gauge group is studied in the context of finite temperature lattice gauge theory. We combine analytical and numerical approaches to extract information about confinement and screening both at low temperatures, and around the deconfinement phase transition. T

Dieter R. Brill

Generalizations of the Black Hole geometry of Ba\~nados, Teitelboim and Zanelli (BTZ) are presented. The theory is three-dimensional vacuum Einstein theory with a negative cosmological constant. The $n$-black-hole solution has $n$ asymptotically anti-de Sitter ``exterior" regions that join in one ``interior" region. The geometry of each exterior region is id

J. Bros, U. Moschella

We present a theory of general two-point functions and of generalized free fields in d-dimensional de Sitter space-time which closely parallels the corresponding minkowskian theory. The usual spectral condition is now replaced by a certain geodesic spectral condition, equivalent to a precise thermal characterization of the corresponding ``vacuum&#39;&#39;sta

P. L. Krapivsky, E. Ben-Naim

We study kinetic and jamming properties of a space covering process in one dimension. The stochastic process is defined as follows: Seeds are nucleated randomly in space and produce rays which grow with a constant velocity. The growth stops upon collision with another ray. For arbitrary distributions of the growth velocity, the exact coverage, velocity and s

K. J. E. Vos, R. J. Gooding

Recent photoemission experiments have measured E vs. k for a single hole propa- gating in antiferromagnetically aligned Sr_2CuO_2Cl_2. Comparisons with (i) the t - t&#39; - J model, for which the carrier is a spinless vacancy, and (ii) a strong-coupling version of the three-band Emery model, for which the carrier is a S = 1/2 hole moving on the Oxygen sublat

L. J. Buchholtz, Mario Palumbo, D. Rainer, J. A. Sauls

We present calculations of the tunneling density of states in an anisotropically paired superconductor for two different sample geometries: a semi-infinite system with a single specular wall, and a slab of finite thickness and infinite lateral extent. In both cases we are interested in the effects of surface pair breaking on the tunneling spectrum. We take t

L. J. Buchholtz, Mario Palumbo, D. Rainer, J. A. Sauls

We study the properties of an anisotropically paired superconductor in the presence of a specularly reflecting surface. The bulk stable phase of the superconducting order parameter is taken to have $d_{x^2-y^2}$ symmetry. Contributions by order parameter components of different symmetries vanish in the bulk, but may enter in the vicinity of a wall. We calcul

David Wolf

The problem of hypothesis testing is examined from both the historical and Bayesian points of view in the case that sampling is from an underlying joint probability distribution and the hypotheses tested for are those of independence and dependence of the underlying distribution. Exact results for the Bayesian method are provided. Asymptotic Bayesian results

J. J. Kamphuis, D. Sijbring, T. S. van Albada

In this paper we present short HI synthesis observations of 57 galaxies without HI information in the RC3. These are a by-product of a large survey with the WSRT of the neutral hydrogen gas in spiral and irregular galaxies. Global profiles and related quantities are given for the 42 detected galaxies and upper limits for the remaining 15. A number of galaxie

L. Brambila Paz, I. Grzegorczyk, P. E. Newstead

Let $X$ be a non-singular projective curve of genus $g\ge2$ over an algebraically closed field of characteristic zero. Let $\mo$ denote the moduli space of stable bundles of rank $n$ and degree $d$ on $X$ and $\wn $ the Brill-Noether loci in $\mo .$ We prove that, if $0\leq d \leq n $ and $\wn $ is non-empty, then it is irreducible of the expected dimension

Cenalo Vaz, Louis Witten

A naked singularity is formed by the collapse of a Sine-Gordon soliton in 1+1 dimensional dilaton gravity with a negative cosmological constant. We examine the quantum stress tensor resulting from the formation of the singularity. Consistent boundary conditions require that the incoming soliton is accompanied by a flux of incoming radiation across past null

Norbert Wex

The Strong Equivalence Principle (SEP) demands, besides the validity of the Einstein Equivalence Principle, that all self-gravitating bodies feel the same acceleration in an external gravitational field. It has been found that metric theories of gravity other that than general relativity typically predict a violation of the SEP. In case of the Earth-Moon sys

Minos Axenides, Andrei Johansen, Holger Bech Nielsen, Ola Tornkvist

The space of static finite-energy configurations in the electroweak theory admits a $Z_2$ topological structure. More precisely, we show that this space contains two disconnected sectors of unstable gauge-Higgs fields odd under a properly defined generalized parity. This classification extends the description of baryon and lepton number violating electroweak

E. Elizalde, S. D. Odintsov

Using the renormalization-group formalism, a sigma model of a special type- in which the metric and the dilaton depend explicitly on one of the string coordinates only-is investigated near two dimensions. It is seen that dilatonic gravity coupled to N scalar fields can be expressed in this form, using a string parametrization, and that it possesses the usual

G. Valencia

I review the estimate of the CP violating asymmetry $A(Λ^0_-)$ within the standard model. I then review the estimate of the upper bound on this asymmetry that arises from measurements of CP violation in kaon decays.

John K. Elwood

The production of the excited charmed baryon doublet $Λ_c^*$ via fragmentation is studied. An analysis of the subsequent hadronic decays of the doublet within the framework of heavy hadron chiral perturbation theory produces expressions for both the angular distribution of the decay products and the polarization of the final state heavy baryon in terms of va

A. Yu. Smirnov

Neutrino data lead via the see-saw mechanism to masses of the right handed neutrinos at the intermediate mass scale. Simple formalism is suggested which incorporates the quark - lepton symmetry and allows one to find properties of the intermediate scale (masses and mixing) from neutrino data. Averaged mass scale and the mass hierarchy parameter are introduce

Peter D. Olmsted, Eugene M. Terentjev

Liquid crystal elastomers present a rich combination of effects associated with orientational symmetry breaking and the underlying rubber elasticity. In this work we focus on the effect of the network on the nematic--smectic-{\sl A} transition, exploring the additional translational symmetry breaking in these elastomers. We incorporate the crosslinks as a ra

Vadim Ponomarenko

Dynamics of the 1D electron transport between two reservoirs are studied based on the inhomogeneous Tomonaga- Luttinger Liquid (ITLL) model in the case when the effect of the electron backscattering on the impurities is negligible. The inhomogeneities of the interaction lead to a charge wave reflection. This effect supposes a special behavior of the transpor

Vadim Ponomarenko

The effect of Coulomb screening on the magnetic impurity behavior is analysed. Two types of the behavior corresponding to either integer or fractional occupation numbers of the low lying magnetic level are described. The features in the dependence of the resistivity on the magnetic field specific for these regimes are predicted.

N. Wex, J. Gil, M. Sendyk

We investigate the possibility of identifying massive objects (lenses) in the Galactic Center region (GC) by means of pulsar timing. The well known intensity change due to microlensing is found to be less important. For typical stellar masses, the flux magnification can be significant only if the lens passes very close to the pulsar--Earth axis. We show that

Neil Turok

A mechanism is presented through which very light scalar degrees of freedom obeying the nonlinear sigma model equation can emerge in spontaneously broken gauge theories. The mechanism operates in extra dimensional theories in which a) there are massless gauge fields present in the theory prior to compactification, and b) the extra dimensions are inhomogeneou

Dung-Hai Lee, Ziqiang Wang

We study the effects of electron-electron interaction on the critical properties of the plateau transitions in the {\it integer} quantum Hall effect. We find the renormalization group dimension associated with short-range interactions to be $-0.66\pm0.04$. Thus the non-interacting fixed point (characterized $z=2$ and $ν\approx 2.3$) is stable. For the Coulom

Orlando Alvarez

This is the written version of lectures presented at Cargese 95. A new formulation for a ``restricted&#39;&#39; type of target space duality in classical two dimensional nonlinear sigma models is presented. The main idea is summarized by the analogy: euclidean geometry is to riemannian geometry as toroidal target space duality is to ``restricted&#39;&#39; ta

D. E. Lanskoy, Yu. A. Lurie, A. M. Shirokov

The $A$-dependence of the bond energy $ΔB_{ΛΛ}$ of the ${ΛΛ}$ hypernuclear ground states is calculated in a three-body ${Λ+ Λ+ {^{A}Z}}$ model and in the Skyrme-Hartree-Fock approach. Various ${ΛΛ}$ and $Λ$-nucleus or ${ΛN}$ potentials are used and the sensitivity of $ΔB_{ΛΛ}$ to the interactions is discussed. It is shown that in medium and heavy ${ΛΛ}$ hype

Marek Jarnicki, Peter Pflug

We present various characterizations of $n$-circled domains of holomorphy $G\subset\CC^n$ with respect to some subspaces of $\Cal H^\infty(G)$.