January 1995 arXiv papers — page 6

Nick Evans

Talks presented at Beyond The Standard Model IV Conference, Lake Tahoe, Dec 94: NEW FERMION FAMILIES AND PRECISION ELECTROWEAK DATA: We highlight a trend in the precision electroweak data towards light new physics and argue that some spectra of strongly interacting technifamilies are plausibly compatible with the data. FERMION MASSES IN EXTENDED TECHNICOLOUR

R. K. Ellis, F. Hautmann, B. R. Webber

We investigate the evolution of parton densities at small values of the momentum fraction, x, by including resummed anomalous dimensions in the renormalization group equations. The resummation takes into account the leading-logarithmic contributions (α_S \ln x)^k given by the BFKL equation and the next-to-leading-logarithmic corrections from quark evolution.

A. Masiero

The available data on large scale structures seem to favour models with mixed dark matter (MDM), i.e. with a hot and cold component in a rather well--defined amount, or with some form of ``warm" dark matter. I discuss some prospects for these new scenarios for DM in the context of supersymmetric extensions of the electroweak standard model. In particular

F. M. Renard

The status of the Standard Model (SM) is reviewed. We emphazize the fact that in spite of the success of the SM for the descrition of the fermionic sector, the status of the bosonic sector (gauge and scalar) suffers from many theoretical deficiencies and from the lack of empirical support. This situation, which leaves room for several types of extensions or

Lesley L. Smith, Pankaj Jain, Douglas W. McKay

The Schwinger-Dyson equation for the quark self-energy is solved for the case of the third and fourth quark generations. The exchanges of standard model gluons and Higgs bosons are taken into account. It is found that Higgs boson exchange dominates quark self-energy in the ultraviolet region for sufficiently large input quark masses, causing the running quar

M. Grüninger, J. Münzel, A. Gaymann, A. Zibold

The mid-infrared spin-wave spectrum of antiferromagnetic YBa$_2$Cu$_3$O$_{6.0}$\ was determined by infrared transmission and reflection measurements ($\bbox{k} \!\! \parallel $c) at $T\!=\!10\!$~K.\@ Excitation of single magnons of the optical branch was observed at $E_{\text{op}}\!=\!178.0\!$~meV.\@ Two further peaks at $346\!$~meV ($\approx\!1.94\,E_{\text

Q. F. Zhong, S. Sorella

We review in details a recently proposed technique to extract information about dynamical correlation functions of many-body hamiltonians with a few Lanczos iterations and without the limitation of finite size. We apply this technique to understand the low energy properties and the dynamical spectral weight of a simple model describing the motion of a single

G. Falci, Rosario Fazio, A. Tagliacozzo, G. Giaquinta

In this letter we consider Andreev tunneling between a normal metal and a one dimensional Josephson junction array with finite-range Coulomb energy. The $I-V$ characteristics strongly deviate from the classical linear Andreev current. We show that the non linear conductance possesses interesting scaling behavior when the chain undergoes a T=0 superconductor-

J. A. Melsen, C. W. J. Beenakker

We consider the effect of disorder on coherent tunneling through two barriers in series, in the regime of overlapping transmission resonances. We present analytical calculations (using random-matrix theory) and numerical simulations (on a lattice) to show that strong mode-mixing in the inter-barrier region induces mesoscopic fluctuations in the conductance $

Geza Odor

The stochastic cellular automaton of Rule 18 defined by Wolfram [Rev. Mod. Phys. 55 601 (1983)] has been investigated by the enhanced coherent anomaly method. Reliable estimate was found for the $β$ critical exponent, based on moderate sized ($n \le 7$) clusters.

Hyesung Kang, T. W. Jones

Direct comparisons of diffusive particle acceleration numerical simulations have been made against Monte Carlo and hybrid plasma simulations by Ellison {\it et. al.} (1993) and against observations at the earth's bow shock presented by Ellison {\it et. al.} (1990). Toward this end we have introduced a new numerical scheme for injection of cosmic-ray part

D. L. Band, L. A. Ford, J. L. Matteson, M. S. Briggs

We evaluate the ability of the BATSE spectroscopy detectors to detect the absorption lines observed by Ginga in gamma ray burst spectra. We find that BATSE can detect the 20.6 keV line in the S1 segment of GB870303 with a detection probability of ~1/4 in nearly normally incident bursts, with the probability dropping off to nearly 0 at a burst angle of 50 deg

P. Barge, J. Sommeria

We explore here the idea, reminiscent in some respect of Von Weizsacker's (1944) and Alfven's (1976) outmoded cosmogonies, that long-lived vortices in a turbulent protoplanetary nebula can capture large amount of solid particles and initiate the formation of planets. Some puzzling features of the solar system appear as natural consequences of our sim

Rashid Faizullin

It's well known that there are structure of the distribution of the nearest light stars (Herschel(1847) and Guld(1879)). Some visual phenomena which connected with numbering by brightness give possible evidence of the existence more thin structure.

Torsten Ekedahl

Actions of finite groups on stable curves are studied. They appear naturally at the boundary of a moduli space of smooth curves with group actions. Those actions which can equivariantly smoothed are characterised. A description of topological types of those actions in terms of the quotient curve and mappings from a kind of fundamental group to the given fini

Michele Cook

This is an addendum to the paper of Braun and Fløystad ([BF]) on the bound for the degree of a smooth surface in $\pfour$ not of general type. Using their construction and the regularity of curves in $\pthree$, one may lower the bound a little more. We will prove the following: Theorem. Let $S$ be a smooth surface of degree $d$ in $\pfour$ not of general typ

Nicola Maggiore

We study the algebraic renormalization of $N=2$ Supersymmetric Yang--Mills theories coupled to matter. A regularization procedure preserving both the BRS invariance and the supersymmetry is not known yet, therefore it is necessary to adopt the algebraic method of renormalization, which does not rely on any regularization scheme. The whole analysis is reduced

N. Ano

A Lagrangian of the topological field theory is found in the twisted osp(2|2)\oplus osp(2|2)conformal super algebra. The reduction on a moduli space is then elaborated through the vanishing Noether current.

Paul C. Eklof, Matthew Foreman, Saharon Shelah

We study the classification of omega_1-separable groups using Ehrenfeucht-Fraisse games and prove a strong classification result assuming PFA, and a strong non-structure theorem assuming diamond.

Martin Goldstern, Saharon Shelah

The bounded proper forcing axiom BPFA is the statement that for any family of aleph_1 many maximal antichains of a proper forcing notion, each of size aleph_1, there is a directed set meeting all these antichains. A regular cardinal kappa is called {Sigma}_1-reflecting, if for any regular cardinal chi, for all formulas phi, ``H(chi) models `phi ' '&#

Tomasz Łuczak, Saharon Shelah

For a sequence p=(p(1),p(2), ...) let G(n,p) denote the random graph with vertex set {1,2, ...,n} in which two vertices i, j are adjacent with probability p(|i-j|), independently for each pair. We study how the convergence of probabilities of first order properties of G(n,p), can be affected by the behaviour of p and the strength of the language we use.

Menachem Magidor, Saharon Shelah

Assuming some large cardinals, a model of ZFC is obtained in which aleph_{omega+1} carries no Aronszajn trees. It is also shown that if lambda is a singular limit of strongly compact cardinals, then lambda^+ carries no Aronszajn trees.

Saharon Shelah

We tried to show in this paper that CH implies: there is a homogeneous family of subset of omega which is maximal with respect to inclusion. The paper is currently "withdrawn", since a mistake has been discovered.

J. L. F. Barbón, K. Demeterfi, I. ~R. Klebanov, C. Schmidhuber

We calculate correlation functions in matrix models modified by trace-squared terms. First we study scaling operators in modified one-matrix models and find that their correlation functions satisfy modified Virasoro constraints. Then we turn to dressed order parameters in minimal models and show that their correlators satisfy Goulian-Li formulae continued to

Michael I. Eides, Valery A. Shelyuto

Corrections to hyperfine splitting and Lamb shift of order $α^2(Zα)^5$ induced by the diagrams with radiative photon insertions in the electron line are calculated in the Fried-Yennie gauge. These contributions are as large as $-7.725(3)α^2(Zα)^5/(πn^3)(m_r/m)^3m$ and $-0.6711(7)α^2(Zα)/(πn^3)E_F$ for the Lamb shift and hyperfine splitting, respectively. Phe

G. Kaelbermann, J. M. Eisenberg

Earlier work reported on the existence of a term within a generalized skyrmion approach that yields appreciable spin content for the proton. Unfortunately there is no accessible experiment that can fix the coefficient of this term directly; plausible but highly uncertain values for it gave a result for the spin content loosely consistent with the currently m

M. H. Friedman

An electric monopole solution to the equations of Maxwell and Einstein's general relativity is displayed. It differs from the usual one in that all components of the metric vanish at large spatial distances from the charge rather than approaching the Minkowski metric. This enables us to find an approximate solution to that for many charges.

Tanmoy Bhattacharya, Rajan Gupta

We present a status report on simulations being done on $32^3 \times 64$ lattices at $β= 6.0$ using quenched Wilson fermions. Phenomenologically relevant results for the spectrum, decay constants, the kaon B-parameter $B_K$, $B_7$, $B_8$, semi-leptonic and $B\to K^* γ$ form factors are given based on a statistical sample of 100 configurations.

Joseph Katz, Shogo Inagaki, Asher Yahalom

The following principle of minimum energy may be a powerful substitute to the dynamical perturbation method, when the latter is hard to apply. Fluid elements of self-gravitating barotropic flows, whose vortex lines extend to the boundary of the fluid, are labelled in such a way that any change of trial configurations automatically preserves mass and circulat

B. Jain, H. J. Mo, S. D. M. White

Hamilton et al. (1991) proposed a simple formula relating the nonlinear autocorrelation function of the mass distribution to the primordial spectrum of density fluctuations for gravitational clustering in an $Ω=1$ universe. High resolution N-body simulations show this formula to work well for scale-free spectra $P(k) \propto k^n$ when the spectral index $n\s

Toshiaki Aida, Yoshihisa Kitazawa, Jun Nishimura, Asato Tsuchiya

We study two--loop renormalization in $(2+ε)$--dimensional quantum gravity. As a first step towards the full calculation, we concentrate on the divergences which are proportional to the number of matter fields. We calculate the $β$ functions and show how the nonlocal divergences as well as the infrared divergences cancel among the diagrams. Although the form

B. Berche, P. E. Berche, M. Henkel, F. Igloi

The influence of a layered aperiodic modulation of the couplings on the critical behaviour of the two-dimensional Ising model is studied in the case of marginal perturbations. The aperiodicity is found to induce anisotropic scaling. The anisotropy exponent z, given by the sum of the surface magnetization scaling dimensions, depends continuously on the modula

T. Hakobyan, A. Sedrakyan

We show that the action of universal $R$-matrix of affine $U_qsl_2$ quantum algebra, when $q$ is a root of unity, can be renormalized by some scalar factor to give a well defined nonsingular expression, satisfying Yang-Baxter equation. It reduced to intertwining operators of all representations, corresponding to Chiral Potts, if the parameters of these repre

Stefano Moretti

The complete matrix element for $e^+e^-\ar b\bar bZ^0Z^0$ has been computed at tree--level and applied to $Z^0H^0$--production followed by $Z^0\ar b\bar b$ and $H^0\ar Z^0Z^0$, including all the irreducible background, at Next Linear Colliders. We find that, assuming flavour identification of the $Z^0$--decay products, this channel, together with $e^+e^-\ar

H. Fusaoka, Y. Koide

A quark mass matrix model $M_q=M_e^{1/2} O_q M_e^{1/2} $ is proposed where $M_e^{1/2}={\rm diag}(\sqrt{m_e},\sqrt{m_μ},\sqrt{m_τ})$ and $O_q$ is a unit matrix plus a rank one matrix. Up- and down-quark mass matrices $M_u$ and $M_d$ are described in terms of charged lepton masses and additional three parameters (one in $M_u$ and two in $M_d$). The model can p

L. J. Hall, S. Raby

A complete supersymmetric SO(10) model is constructed, which is the most general consistent with certain $R$, discrete, and $U(1)$ flavor symmetries. The desired vacuum of the theory has vevs which lie in particular directions of group space. This leads to both doublet triplet splitting and to the generation of just four operators for charged fermion masses.

Joseph D. Romano

A canonical formalism for spherical symmetry, originally developed by Kuchař to describe vacuum Schwarzschild black holes, is extended to include a spherically symmetric, massless, scalar field source. By introducing the ADM mass as a canonical coordinate on phase space, one finds that the super-Hamiltonian and supermomentum constraints for the coupled syste

George Kirczenow

The remarkably large persistent currents that are observed in disordered micron-scale gold rings at low temperatures have recently been explained in a theory of non-interacting electrons scattered by crystal grain boundaries. The present article examines the possibility that the basic physics underlying this explanation may also have observable consequences

J. Betouras, R. Joynt

In a recent experiment, Ma et al. measured the temperature dependence of the gap anisotropy of oxygen-annealed Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$. Their measurements were taken along the two directions $Γ- M$ and $Γ- X$. They found that the gap along both directions is nonzero at low temperatures and that the ratio is strongly temperature dependent. We show

T. Chou, S. K. Lucas, H. A. Stone

The study of capillary wave scattering by a circular region with different interfacial properties from the rest of an otherwise homogeneous interface is motivated by experiments on wave attenuation at a monolayer covered air-water interface where domains of one surface phase are dispersed in a second surface phase. Here the scattering function is calculated

F. Wang, E. G. D. Cohen

We study numerically the nature of the diffusion process on a honeycomb and a quasi-lattice, where a point particle, moving along the bonds of the lattice, scatters from randomly placed scatterers on the lattice sites according to strictly deterministic rules. For the honeycomb lattice fully occupied by fixed rotators two (symmetric) isolated critical points

Eric Braaten, Sean Fleming

The QCD radiative corrections to the leptonic decay rate of the $B_c$ meson are calculated using the formalism of nonrelativistic QCD (NRQCD) to separate short-distance and long-distance effects. The $B_c$ decay constant is factored into a sum of NRQCD matrix elements each multiplied by a short-distance coefficient. The short-distance coefficient for the lea

K. Abe

We have searched for signatures of polarization in hadronic jets from $Z^0 \to q \bar{q}$ decays using the ``jet handedness'' method. The polar angle asymmetry induced by the high SLC electron-beam polarization was used to separate quark jets from antiquark jets, expected to be left- and right-polarized, respectively. We find no evidence for jet hand

Arthur Kosowsky

Polarization of the cosmic microwave background, though not yet detected, provides a source of information about cosmological parameters complementary to temperature fluctuations. This paper provides a complete theoretical treatment of polarization fluctuations. After a discussion of the physics of polarization, the Boltzmann equation governing the evolution

Chetan Nayak, Frank Wilczek

We identify some hidden symmetries of Chern-Simons theories, such as appear in the effective theory for quantized Hall states. This allows us to determine which filling fractions admit spin-singlet quantum Hall states. Our results shed some light on states already observed at $ν=2/3$, and transitions between them. We identify SU(2), or higher, symmetries of

R. Podgornik

A microscopic model of a surface polymer network - membrane system is introduced, with contact polymer surface interactions that can be either repulsive or attractive and sliplinks of functionality four randomly distributed over the supporting membrane surface anchoring the polymers to it. For the supporting surface perturbed from a planar configuration and

Richard Levien, Chetan Nayak, Frank Wilczek

Highly correlated states of electrons are thought to produce quasiparticles with very unusual properties. Here we consider how these properties are manifested in space-time propagation. Specifically, we discuss how spin-charge separation is realized in a simple double-layer geometry, how mass renormalization affects time-of-flight in compressible Hall states

Vladimir O. Soloviev

It is shown that the new Poisson brackets proposed in Part I of this work (J. Math. Phys. 34, 5747(hep-th/9305133)) arise naturally in an extension of the formal variational calculus incorporating divergences. The linear spaces of local functionals, evolutionary vector fields, functional forms, multi-vectors and differential operators become graded with resp

M. Fukugita, Y. Kuramashi, M. Okawa, A. Ukawa

A lattice QCD calculation of the proton matrix element of the flavor singlet axial-vector current is reported. Both the connected and disconnected contributions are calculated, for the latter employing the variant method of wall source without gauge fixing. From simulations in quenched QCD with the Wilson quark action on a $16^3\times 20$ lattice at $β=5.7$

Jonathan L. Rosner

The spectra of states containing charmed and beauty quarks, and their regularities, are reviewed.

B. Reznik, Y. Aharonov

We explore further the suggestion to describe a pre- and post-selected system by a two-state, which is determined by two conditions. Starting with a formal definition of a two-state Hilbert space and basic operations, we systematically recast the basics of quantum mechanics - dynamics, observables, and measurement theory - in terms of two-states as the eleme

K. Abe

We present a comparison of the strong couplings of light ($u$,~$d$,~and~$s$), $c$, and $b$ quarks determined from multijet rates in flavor-tagged samples of hadronic $Z^0$ decays recorded with the SLC Large Detector at the SLAC Linear Collider. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, $c$,

Murray Peshkin, H. J. Lipkin

Recent neutron interferometry experiments have been interpreted as demonstrating a new topological phenomenon similar in principle to the usual Aharonov-Bohm (AB) effect, but with the neutron's magnetic moment replacing the electron's charge. We show that the new phenomenon, called Scalar AB (SAB) effect, follows from an ordinary local interaction, c

A. Borowiec, V. K. Kharchenko

A new notion of an optimal algebra for a first order coordinate differential was introduced in \cite{BKO}. Some relevant examples are indicated. Quadratic identities in the optimal algebras and calculi on quadratic algebras are studied. Canonical construction of a quantum de Rham complex for the coordinate differential is proposed. The relations between calc

Bong H. Lian, Gregg J. Zuckerman

We construct a new cohomology functor from the a certain category of {\it quantum operator algebras} to the category of {\it Batalin-Vilkovisky algebras}. This {\it Moonshine cohomology} has, as a group of natural automorphisms, the Fischer-Griess Monster finite group. We prove a general vanishing theorem for this cohomology. For a certain commutative QOA at

Bong H. Lian, Gregg J. Zuckerman

A key notion bridging the gap between {\it quantum operator algebras} \cite{LZ10} and {\it vertex operator algebras} \cite{Bor}\cite{FLM} is the definition of the commutativity of a pair of quantum operators (see section 2 below). This is not commutativity in any ordinary sense, but it is clearly the correct generalization to the quantum context. The main pu

S. Kharchev, A. Mironov, A. Morozov

One possible way to fix partly a ``canonical definition'' of $τ$-functions beyond the conventional KP/Toda framework could be to postulate that evolution operators are {\it always} group elements. We discuss implications of this postulate for the first non-trivial case: fundamental representations of quantum groups $SL_q(N)$. It appears that the most

M. B. Barbaro, A. De Pace, T. W. Donnelly, A. Molinari

The quasielastic longitudinal electromagnetic response function R_L is studied within the context of a model that extends our previous investigations of pionic correlations and currents. Four mesons are now employed (pion, rho, sigma and omega, via the Bonn potential) and the many-body dynamics are extended to the full random-phase approximation built upon a

Andy Strominger

Contents: 1. Introduction 2. Causal Structure and Penrose Diagrams: Minkowski Space; 1+1 Dimensional Minkowski Space; Schwarzchild Black Holes; Gravitational Collapse and the Vaidya Spacetimes; Event Horizons, Apparent Horizons, and Trapped Surfaces 3. Black Holes in Two Dimensions: General Relativity in the $S$-Wave Sector; Classical Dilaton Gravity; Eterna

M. Gasperini, R. Ricci

We present exact solutions characterised by Bianchi-type I,II,III,V,VI four-dimensional metric, space-independent dilaton, and vanishing torsion background, for the low energy string effective action with zero central charge deficit. We show that, in such a context, curvature singularities cannot be avoided, except for the trivial case of flat spacetime and

B. L. Hu, K. Shiokawa

Decoherence in quantum systems which are classically chaotic is studied. It is well-known that a classically chaotic system when quantized loses many prominent chaotic traits. We show that interaction of the quantum system with an environment can under general circumstances quickly diminish quantum coherence and reenact some characteristic classical chaotic

T. Banks, M. Berkooz, P. J. Steinhardt

A survey of solutions to the cosmological moduli problem in string theory. The only extant proposal which may work is Intermediate Scale Inflation as proposed by Randall and Thomas. Supersymmetry preserving dynamics which could give large masses to the moduli is strongly constrained by cosmology and requires the existence of string vacuum states possessing p

Douglas Singleton

Drawing on the parallel between general relativity and Yang-Mills theory we obtain an exact Schwarzschild-like solution for SU(2) gauge fields coupled to a massless scalar field. Pushing the analogy further we speculate that this classical solution to the Yang-Mills equations shows confinement in the same way that particles become confined once they pass the

Igor Pesando

We consider the (massive) Gross-Neveu model using the light cone quantization where we solve the constraints explicitly. We show that the vacuum is trivial and that the quantization fails when $m=0$. We discuss how the running coupling constant emerges as a pure normal ordering effect in this context and the bound state equation.

J. Ambjorn, Y. Watabiki

The 2-point function is the natural object in quantum gravity for extracting critical behavior: The exponential fall off of the 2-point function with geodesic distance determines the fractal dimension $d_H$ of space-time. The integral of the 2-point function determines the entropy exponent $γ$, i.e. the fractal structure related to baby universes, while the

E. Elizalde, K. Kirsten, S. Zerbini

We apply the Mellin-Barnes integral representation to several situations of interest in mathematical-physics. At the purely mathematical level, we derive useful asymptotic expansions of different zeta-functions and partition functions. These results are then employed in different topics of quantum field theory, which include the high-temperature expansion of

I. L. Buchbinder, S. M. Kuzenko, A. Yu. Petrov, J. V. Yarevskaya

A superfield method of computing the effective potential in supersymmetric field theories is suggested. Analysis of the structure of the effective potential in the Wess-Zumino model is carried out. It is shown that the superfield effective potential is defined by three objects: kahlerian effective potential, chiral effective potential and auxiliary fields&#3

Hak-Soo Shin, Kwang-Sup Soh

The CGHS model of two-dimensional dilaton gravity coupled to a sine-Gordon matter field is considered. The theory is exactly solvable classically, and the solutions of a kink and two-kink type solitons are studied in connection with black hole formation.

Martin O'Loughlin

We introduce a new parametrisation for the Fermi sea of the $c = 1$ matrix model. This leads to a simple derivation of the scattering matrix, and a calculation of boundary corrections in the corresponding $1+1$--dimensional string theory. The new parametrisation involves relativistic chiral fields, rather than the non-relativistic fields of the usual formula

T. NAKATSU, K. TAKASAKI, S. TSUJIMARU

The quantum and classical aspects of a deformed $c=1$ matrix model proposed by Jevicki and Yoneya are studied. String equations are formulated in the framework of Toda lattice hierarchy. The Whittaker functions now play the role of generalized Airy functions in $c<1$ strings. This matrix model has two distinct parameters. Identification of the string couplin

Gary R. Goldstein, R. L. Jaffe, Xiangdong Ji

Various issues surrounding a recently proposed inequality among twist-two quark distributions in the nucleon are discussed. We provide a rigorous derivation of the inequality in QCD, including radiative corrections and scale dependence. We also give a more heuristic, but more physical derivation, from which we show that a similar inequality does not exist am

W. F. Palmer, Y. L. Wu

We present a general model-independent and rephase-invariant formalism that cleanly relates observables to the fundamental parameters and explicitly separates different types of CP violation in the $B^0$-, $D^0$- and $K^0$- systems. We emphasize its importance when interpreting experimental measurement of CP violation, the unitarity triangle, and probes of n

J. Lopez, D. Nanopoulos

We propose a new cosmological model with a time-dependent cosmological constant ($Λ\propto 1/t^2$), which starting at the Planck time as $Λ_{Pl}\sim M^2_{Pl}$, evolves to the present-day allowed value of $Λ_0\sim10^{-120}M^2_{Pl}$. This scenario is supported by non-critical string theory considerations. We compute the age of the Universe and the time-depende

W. Beenakker, R. Höpker, P. M. Zerwas

We present the distributions for gluon radiation off stop-antistop particles produced in $e^+e^-$ annihilation: $e^+e^- \to \tilde t \bar{\tilde t} g$. For high energies the splitting functions of the fragmentation processes $\tilde t \to \tilde t g$ and $g \to \tilde t \bar{\tilde t}$ are derived; they are universal and apply also to high-energy stop partic

Ph. Boucaud

We present results for the radiative decay $B\to K^* γ$, obtained by using the Clover action at $β= 6.0$ on APE. The compatibility between the scaling laws predicted by the Heavy Quark Effective Theory (HQET) and pole dominance is discussed. The final result depends crucially on the assumed $q^2$-dependence of the form factors.

Th. Lippert, A. Bode, V. Bornyakov, K. Schilling

Pure gauge compact QED on hypercubic lattices is considered with periodically closed monopole currents suppressed. We compute observables on sublattices which are nested around the centre of the lattice in order to locate regions where translation symmetry is approximately recovered. Our Monte Carlo simulations on $24^4$-lattices give indications for a first

S. Güsken, K. Schilling, G. Siegert

We present intermediate results on our ongoing investigation concerning semileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector mesons. The corresponding formfactors are evaluated at several momenta and appropriate combinations of four light and four heavy quarks, which are chosen to allow for an extrapolation into the B Meson region. I

E. Mendel, L. Polley

Susskind&#39;s continuous-time fermions, with two flavours, can be latticized using a one-sided time derivative. We are presently investigating the interacting case, where we hope to find the onset at finite $μ$ at the right place due to the reduced number of flavours. As for these fermions there is only a discrete chiral symmetry left over, the lightness of

Walter Wilcox, Simeon Trendafilov, Eduardo Mendel

Nonzero chemical potential studies with Wilson fermions should avoid the proliferation of flavor-equivalent nucleon states encountered with staggered formulation of fermions. However, conventional wisdom has been that finite baryon density calculations with Wilson fermions will be prohibitively expensive. We demonstrate that the volume method applied to Wils

S. W. Hawking, Gary. T. Horowitz

We give a general derivation of the gravitational hamiltonian starting from the Einstein-Hilbert action, keeping track of all surface terms. The surface term that arises in the hamiltonian can be taken as the definition of the `total energy&#39;, even for spacetimes that are not asymptotically flat. (In the asymptotically flat case, it agrees with the usual

Pietro Menotti, Domenico Seminara

It is shown that the Fermi-Walker gauge allows the general solution of determining the metric given the sources, in terms of simple quadratures. We treat the general stationary problem providing explicit solving formulas for the metric and explicit support conditions for the energy momentum tensor. The same type of solution is obtained for the time dependent

A. Burinskii, R. P. Kerr

The Kerr solution is defined by a null congruence which is geodesic and shear free and has a singular line contained in a bounded region of space. A generalization of the Kerr congruence for nonstationary case is obtained. We find a nonstationary shear free geodesic null congruence which is generated by a given analytical complex world line. Solutions of the

R. Ferrari

We introduce and study the Wannier functions for an electron moving in a plane under the influence of a perpendicular uniform and constant magnetic field. The relevance for the Fractional Quantum Hall Effect is discussed; in particular it shown that an interesting Hartree-Fock state can be constructed in terms of Wannier functions.

Daniel Koller, Michael C. Martin, Peter W. Stephens, Laszlo Mihaly

Infrared transmission, electron spin resonance, and X-ray diffraction measurements show unambiguously that RbC$_{60}$ and KC$_{60}$ are stable in air, in contrast to Rb$_{6}$C$_{60}$ which decomposes rapidly upon exposure. The specimens studied transform into pure C$_{60}$ and other byproducts when heated above $100\dd $C, approximately the temperature of th

Haranath Ghosh, M. Sardar

Interlayer single particle tunneling between the $Cu-O$ layers suppress the in-plane short range magnetic order (which is modeled as spin density wave (SDW) insulator). Doping over the SDW state kills perfect nesting of the Fermi surface (FS) in certain directions and hence SDW gap reduces to zero in those directions of the FS. Coupling between the planes th

Hyoungsoo Yoon, J. M. Deutsch

We study the diffusion of a linear polymer in the presence of permeable membranes without excluded volume interactions, using scaling theory and Monte Carlo simulations. We find that the average time it takes for a chain with polymerization index~$N$ to cross a single isolated membrane varies with~$N$ as~% $N^{5/2}$, giving its permeability proportional to~$

George Kirczenow

It is demonstrated using three-dimensional computer simulations that some simple non-interacting electron models that include electron scattering by grain boundaries, exhibit coexistence of large persistent currents and small conductances, similar to that observed experimentally in isolated micron-scale gold rings. Models with simple grain boundaries, and mo

Y. Chen, H. Ohashi, M. Akiyama

The lattice Bhatnagar-Gross-Krook modeled fluid has an unchangeable unit Prandtl number. A simple method is introduced in this letter to formulate a flexible Prandtl number for the modeled fluid. The effectiveness was demonstrated by numerical simulations of the Couette flow.

Qisu Zou, Shuling Hou, Gary D. Doolen

Analytical solutions of the two dimensional triangular and square lattice Boltzmann BGK models have been obtained for the plain Poiseuille flow and the plain Couette flow. The analytical solutions are written in terms of the characteristic velocity of the flow, the single relaxation time $τ$ and the lattice spacing. The analytic solutions are the exact repre

M. Carollo, T. de Zeeuw, R. van der Marel, J. Danziger

We present measurements of the shape of the stellar line-of-sight velocity distribution out to two effective radii along the major axes of the four elliptical galaxies NGC 2434, 2663, 3706, and 5018. The velocity dispersion profiles are flat or decline gently with radius. We compare the data to the predictions of f=f(E,L_z) axisymmetric models with and witho

David H Lyth, Andrzei Woszczyna

When considering perturbations in an open (Omega<1) universe, cosmologists retain only sub-curvature modes (defined as eigenfunctions of the Laplacian whose eigenvalue is less than -1 in units of the curvature scale, in contrast with the super-curvature modes whose eigenvalue is between -1 and 0). Mathematicians have known for almost half a century that all

L. Danese, L. Toffolatti, A. Franceschini, M. Bersanelli

Extensive, accurate imaging of the Cosmic Background Radiation temperature anisotropy at sub--degree angular resolution is widely recognized as one of the most crucial goals for cosmology and astroparticle physics in the next decade. We review the scientific case for such measurements in relation with sky coverage, attainable sensitivity, confusing foregroun

Peter Vorob&#39;ev, Igor&#39; Kolokolov

We propose experimental schemes for detection an axionic condensate supposed to be cosmic dark matter. Various procedures are considered in dependence on the value of the axion mass. There are well known indications that a large part of the Universe mass exists in a form of dark matter: The analysis of rotation curves of galaxies leads to the conclusion that

Haruhiko Ueda, Jun&#39;ichi Yokoyama

Evolution of the statistical distribution of density field is investigated by means of a counts-in-cells method in a low-density cold-dark-matter simulated universe. Four theoretical distributions, i.e. the negative binomial distribution, the lognormal distribution, the Edgeworth series and the skewed lognormal distribution, are tested to fit the calculated

Lorenzo Sadun

For $SU(2)$ (or $SO(3)$) Donaldson theory on a 4-manifold $X$, we construct a simple geometric representative for $μ$ of a point. Let $p$ be a generic point in $X$. Then the set $\{ [A] | F_A^-(p) $ is reducible $\}$, with coefficient -1/4 and appropriate orientation, is our desired geometric representative.

Alon Faraggi

All the realistic free fermionic models utilize a set of basis vectors, the NAHE set, that correspond to $Z_2\times Z_2$ orbifold compactification with nontrivial background fields. I argue that the realistic features of free fermionic models, like the number of generations and the fermion mass spectrum are due to the underlying $Z_2\times Z_2$ orbifold comp

Javier Mas, Eduardo Ramos

Recently much attention has been paid to the restriction of KP to the submanifold of operators which can be represented as a ratio of two purely differential operators L=AB^{-1}. Whereas most of the aspects concerning this reduced hierarchy, like the Lax flows and the Hamiltonians, are by now well understood, there still lacks a clear and conclusive statemen

Markus Finkemeier

We reexamine radiative corrections to $π_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, including vector and axial vector resonances as explicit degrees of freedom in the long distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by comparing with model independent estimates, we scrutinize the m

P. Kosinski, M. Majewski, P. Maslanka

The representations of the oscillator algebra introduced by Brzezinski et al. (Phys. Lett. B 311 (1993), 202) are classified.

S. Giller, C. Gonera, P. Kosinski, P. Maslanka

Fourdimensional bicovariant differential calculus on quantum E(2) group is constructed.