November 1995 arXiv papers — page 9

F. Bagehorn, J. Lorenc, Cz. Oleksy

We propose a lattice gas model to account for linear chain structures adsorbed on (112) faces of W and Mo. The model includes a dipole-dipole interaction as well as a long-ranged indirect interaction. We have explicitly demonstrated that the periodic ground states depend on a competition between dipole-dipole and indirect interaction. The effect of temperatu

Daniel Gordon, Greg Kuperberg, Oren Patashnik, Joel Spencer

A (v,k,t) covering design, or covering, is a family of k-subsets, called blocks, chosen from a v-set, such that each t-subset is contained in at least one of the blocks. The number of blocks is the covering's size}, and the minimum size of such a covering is denoted by C(v,k,t). It is easy to see that a covering must contain at least (v choose t)/(k choo

G. E. Arutyunov, P. B. Medvedev

By applying the Hamiltonian reduction scheme we recover the R-matrix of the trigonometric and elliptic Calogero-Moser system.

S. Monni, M. Cadoni

We find exact charged black hole solutions of a string effective action that is invariant under S-duality transformations. These black hole solutions have the same causal structure as the Reissner-Nordstrom (RN) solutions. They reduce to the RN solutions for self-dual configurations of the dilaton and to the Garfinkle-Horowitz-Strominger (GHS) solution in th

Fiorenzo Bastianelli

A proof for a non-perturbative C-theorem in four dimensions, capturing the irreversibility of the renormalization group flow in the space of unitary quantum field theories, has not been accomplished, yet. We test the conjectured C-theorems using the exact results recently obtained in N=1 supersymmetric gauge theories. We find that the flow towards the infrar

Chi-Keung Chow

In the large $N_c$ limit, one can describe normal heavy baryons $Qqq$ and heavy pentaquarks $\bar Qqqqq$ as bound states of heavy mesons to chiral (anti)solitons. In this picture, the strong and electromagnetic decay parameters of these hadrons can be calculated from those of the constituent heavy mesons and light baryons, while the weak decay form factors c

Y. N Srivastava, A. Widom, E. Sassaroli

The implication of the many time formalism for the process $Φ$ $\rightarrow$ $K^0 \ + {\bar K}^0$ was discussed in a recent letter of B. Kayser and L. Stodolsky who predicted a small correction ($\sim\ 5 \%$) to the usually predicted phase ocillations frequency for forthcoming $Φ$ factory experiments. Based on previous work (also using the many proper times

J. R. Morris

A supersymmetric extension of the $U(1)\times U(1)^{\prime }$-Higgs bosonic superconducting cosmic string model is considered,and the constraints imposed upon such a model due to renormalizability, supersymmetry, and gauge invariance are examined. For a simple model with a single $U(1)$ chiral superfield and a single $% U(1)^{\prime }$ chiral superfield, the

J. Manjavidze

For description of the quantum dynamics on a curved group manifold the path integrals in a space of the group parameters is offered. The formalism is illustrated by the $H$-atom problem.

M. V. Chizhov

The semileptonic kaon decays $K_{l2γ}$ and $K_{l3}$ are considered. We use the most general forms of the matrix elements for these decays. Additional terms could arise as a result of new tensor interactions between quarks and leptons. Such terms have been detected in a recent experiments. The high precision experiments at DA$Φ$NE may be ideal to confirm thes

E. Calabresu, G. Fiorentini, M. Lissia, B. Ricci

We extract information on the fluxes of Be and CNO neutrinos directly from solar neutrino experiments, with minimal assumptions about solar models. Next we compare these results with solar models, both standard and non standard ones. Finally we discuss the expectations for Borexino, both in the case of standard and non standard neutrinos.

A. Ali Khan

The phase diagram of non-compact lattice QED in four dimensions with staggered fermions of charges 1 and $-1/2$ is investigated. The renormalized charges are determined and found to be in agreement with perturbation theory. This is an indication that there is no continuum limit with non-vanishing renormalized gauge coupling, and that the theory has a validit

G. Giachetta, G. Sardanashvily

We show that the covariant derivative of Dirac fermion fields in the presence of a general linear connection on a world manifold is universal for Einstein's, gauge and affine-metric gravitation theories.

Hans-Juergen Matschull

A manifestly diffeomorphism invariant extension of Einstein gravity is constructed, which includes singular metrics, and whose ADM formulation is Ashtekar's gravity. The latter is shown to be locally equivalent to the covariant theory. It turns out that exactly those kinds of degenerate four dimensional metrics are allowed which do not destroy the causal

Benjamin J. Owen

It has long been known that the search for gravitational waves from inspiraling binaries must be aided by signal processing methods, and that the technique of matched filtering is the most likely to be used for the detection of inspiral ``chirps''. This means that the output of an interferometer must be cross- correlated with many waveform templates

H. -B. Schuttler, M. R. Norman

We compare the normal-state resistivities $ρ$ and the critical temperatures $T_c$ for superconducting $d_{x^2-y^2}$ pairing due to antiferromagnetic (AF) spin fluctuation exchange in the context of the two phenomenological dynamical spin susceptibility models, recently proposed by Millis, Monien, and Pines (MMP) and Monthoux and Pines (MP) and, respectively,

G. Paladin, M. Serva

The partition function of the 2d Ising model with random nearest neighbor coupling is expressed in the dual lattice made of square plaquettes. The dual model is solved in the the mean field and in different types of Bethe-Peierls approximations, using the replica method.

Z. Kaufmann, H. Lustfeld, J. Bene

The spectral properties of the Frobenius-Perron operator of one-dimensional maps are studied when approaching a weakly intermittent situation. Numerical investigation of a particular family of maps shows that the spectrum becomes extremely dense and the eigenfunctions become concentrated in the vicinity of the intermittent fixed point. Analytical considerati

E. M. de Gouveia Dal Pino, J. E. Horvath, J. A. de Freitas Pacheco

We analyze the primordial protogalactic gas to investigate the role of thermal instabilities in the formation of condensations that could contribute to the MACHO mass function. We find that the previrialized protogalaxy could have undergone a thermally unstable regime which defines a peak in mass condensations starting around $0.1 \, M_{\odot}$ after being r

Philip D. Mannheim

We explore the possibility that the entire departure of galactic rotational velocities from their luminous Newtonian expectation be cosmological in origin, and show that within the framework of conformal gravity (but not Einstein gravity apparently) every static observer sees the overall Hubble flow as a local universal linear potential which is able to acco

Andreas Reisenegger, Jordi Miralda-Escude, Eli Waxman

The X-ray emission by hot gas at the centers of clusters of galaxies is commonly modeled assuming the existence of steady-state, inhomogeneous cooling flows. We derive the metallicity profiles of the intracluster medium expected from such models. The inflowing gas is chemically enriched by type Ia supernovae and stellar mass loss in the outer parts of the ce

Eric J. Bakker, Henny J. G. L. M. Lamers, L. B. F. M. Waters, Christoffel Waelkens

We have searched for periodicity in the photometric and spectroscopic variations of the enigmatic star HD 101584 and found a long-term variability on a typical time scale of 1700 days (4.7 years) and a highly significant period of 218+-0.7 day. This period is most prominently present in the photometric indices which are a measure for the Balmer jump (Geneva

Georg G. Raffelt

The dynamics of the universe may be dominated by novel weakly interacting elementary particles, by baryons in an invisible form, by black holes, and globally by vacuum energy. The main arguments for and against such hypotheses are reviewed.

Paul Francis, Bruce Woodgate, Steve Warren, Palle Moller

We report the discovery of a group of galaxies at redshift 2.38. We imaged about 10% of a claimed supercluster of QSO absorption-lines at z=2.38 (Francis & Hewett 1993). In this small field (2 arcmin radius) we detect two Ly-alpha emitting galaxies. The discovery of two such galaxies in our tiny field supports Francis & Hewett's interpretation of the abs

Bing-Lin Young

In this talk I will use effective lagrangian and discuss possible new physics associated with top quark.

G. K. Leontaris, N. D. Tracas

We discuss the low energy implications of gauge coupling unification at the string scale, taking into account string threshold corrections in the $SU(4) {\times} O(4)$ model. We express $sin^2θ_W$ and $a_3$ as functions of the calculable string threshold differences and discuss simple examples of spectra which retain the successful predictions of the supersy

Mark Evans, Ioannis Giannakis

T-Duality is a poorly understood symmetry of the space-time fields of string theory that interchanges long and short distances. It is best understood in the context of toroidal compactification where, loosely speaking, radii of the torus are inverted. Even in this case, however, conventional techniques permit an understanding of the transformations only in t

Thomas D. Cohen

It is possible that isospin violating dynamical effects are amplified due to coherence if a disoriented chiral condensate (or other source of a coherent pion state) is formed in a heavy ion collison. It is shown explicitly that altering the isospin of the coherent state by order of one unit can change the number of $π^0$'s in the condensate by some finit

J. S. Dowker, J. S. Apps, K. Kirsten, M. Bordag

The mode properties for spectral and mixed boundary conditions for massless spin-half fields are derived for the $d$--ball. The corresponding functional determinants and heat-kernel coefficients are presented, the latter as polynomials in $d$.

K. Kobayakawa, Y. Sato, S. Tanaka

We point out the possibility to detect the low-energy signals of moduli in the superstring theory through the neutrino oscillation. The idea is based on the characteristics that the couplings of moduli are different from matter to matter. We estimate the oscillation probability both in the baseline and solar neutrino oscillations. In both cases, when there i

M. Daumer, D. Dürr, S. Goldstein, N. Zanghi

The quantum probability flux of a particle integrated over time and a distant surface gives the probability for the particle crossing that surface at some time. We prove the free Flux-Across-Surfaces Theorem, which was conjectured by Combes, Newton and Shtokhamer, and which relates the integrated quantum flux to the usual quantum mechanical formula for the c

Chang Won Lee

The Galactic Center regions $-6^\circ \le l \le 6^\circ$ and $-0.8^\circ \le b \le 0.87^\circ$ are surveyed with HCN J=1$-$0 line (88.6 GHz) on a 4$'$ grid with the 14 m telescope at the Taeduk Radio Astronomy Observatory. The data complement the previous $^{13}$CO, CS, and H$_2$CO measurements (Bally \etal 1988, Zylka \etal 1992) but cover a wider area

Azat M. Latypov

Approximate group analysis technique, that is, the technique combining the methodology of group analysis and theory of small perturbations, is applied to finite-difference equations approximating ordinary differential equations. Finite-difference equations are viewed as a system of algebraic equations with a small parameter, introduced through the definition

Alessandro Torcini, Helge Frauenkron, Peter Grassberger

A new integration scheme, combining the stability and the precision of usual pseudo-spectral codes with the locality of finite differences methods, is introduced. It turns out to be particularly suitable for the study of front and disturbance propagation in extended systems. An application to the complex Ginzburg-Landau equation shows the higher precision of

A. Sibirtsev, K. Tsushima, Amand Faessler

The $Δ$-excitation in $\overline{p}d$ annihilation at rest was studied. The annihilation amplitude from the statistical model and the $πN$ amplitude from the resonance model were adopted in our calculations. We analyze the invariant mass of the $π^+p$ and $π^-p$ systems selecting the protons with momenta above 400 MeV/c and with respect to the different fina

David Goldberg, Rebecca A. Herb

We examine the theory of induced representations for non-connected reductive $p$-adic groups for which $G/G^0$ is abelian. We first examine the structure of those representations of the form $\Ind_{P^0}^G(σ),$ where $P^0$ is a parabolic subgroup of $G^0$ and $\s$ is a discrete series representation of the Levi component of $P^0.$ Here we develop a theory of

Finn Larsen, Frank Wilczek

We present a number of qualitative arguments which strongly suggest that extremal dyonic black holes in the 4--dimensional low energy, classical field theory limit of toroidally compactified heterotic string theory represent largely degenerate classes of states in the quantum theory. We propose a simple expression for the full non--perturbative degeneracy, w

Mikhail Vasiliev

We formulate a new model which describes higher-spin gauge interactions for matter fields in two dimensions. This model is a higher-spin generalization of d2 gravity and turns out to be integrable. No vanishing higher-spin current conditions are imposed on the matter fields.

V. Ya. Fainberg, M. S. Shikakhwa

Starting from the generating functional of the theory of relativistic spinors in 2+1 dimensions interacting through the pure Chern-Simons gauge field, the S-matrix is constructed and seen to be formally the same as that of spinor quantum electrodynamics in 2+1 dimensions with Feynman diagrams having external photon lines excluded, and with the propagator of

Monika Lynker, Rolf Schimmrigk

Recent work initiated by Strominger has lead to a consistent physical interpretation of certain types of transitions between different string vacua. These transitions, discovered several years ago, involve singular conifold configurations which connect distinct Calabi-Yau manifolds. In this paper we discuss a number of aspects of conifold transitions pertine

Ya. I. Azimov

The model-independent formalism is constructed to describe decays of mixed particles without using the Weisskopf-Wigner approximation. Limitations due to various symmetries are traced for neutral $K-$mesons. As an application we show that effects of $CPT-$violation and going beyond WWA may be separated and studied independently.

Shaaban Khalil, Antonio Masiero, Francesco Vissani

We study the phenomenological implications of effective supergravities based on string vacua with spontaneously broken N=1 supersymmetry by dilaton and moduli $F$-terms. We further require Minimal String Unification, namely that large string threshold corrections ensure the correct unification of the gauge couplings at the grand unification scale. The whole

M. M. Islam

Analyses of high energy elastic pp and $\bar pp$ scattering data from CERN ISR and SPS Collider seem to provide strong evidence in favor of the gauged nonlinear sigma-model of the nucleon. This model describes the nucleon as a topological soliton and introduces the vector mesons omega, rho, a1 as gauge bosons. The model, however, needs to be extended to incl

S. Dittmaier, D. Schildknecht, G. Weiglein

The nature of the electroweak bosonic loop corrections to which current precision experiments are sensitive is explored. The set of effective parameters $\De x$, $\De y$, and $\eps$, which quantify SU(2) violation in an effective Lagrangian, is shown to be particularly useful for this purpose. The standard bosonic corrections are sizable only in the paramete

Bohdan Grzadkowski

The process of top quark pair production at Next Linear Collider (NLC) has been considered adopting an effective Lagrangian approach and including all operators of dim~6 which can be tree-level-generated within unknown underlying theory. All contributing helicity amplitudes are presented. It has been found that four-fermion operators can provide the leading

Marcelo Gleiser

A reply to a Comment by Harris and Jungman (Phys. Rev. Lett. 75 (1995), 588), concerning my work on phase mixing and its implications to the dynamics of ``weak'' first order phase transitions.

F. Franke, H. Fraas

Within the framework of the Next-To-Minimal Supersymmetric Standard Model (NMSSM) we study neutralino production $e^+e^- \longrightarrow \tildeχ^0_i \tildeχ^0_j$ ($i,j=1,\ldots ,5$) at center-of-mass energies between 100 and 600 GeV and the decays of the heavier neutralinos into the LSP plus a fermion pair, a photon or a Higgs boson. For representative gaugi

Thierry Gousset, Bernard Pire

We review the theory of hard exclusive scattering in Quantum Chromodynamics. After recalling the classical counting rules which describe the leading scale dependence of form factors and elastic reactions at fixed angle, the pedagogical example of the pion form factor is developped in some detail in order to show explicitely what factorization means in the QC

E. Marinari, M. L. Paciello, G. Parisi, B. Taglienti

We introduce a new numerical technique to compute mass spectra, based on difference method and on a new gauge fixing procedure. We show that the method is very effective by test runs on a $SU(2)$ lattice gauge theory.

S. Marti i Garcia

Three jet events arising from decays of the $Z^0$ boson, collected by the DELPHI detector at LEP, were used to measure differences in the properties of quark and gluon jet fragmentation. Gluon jets were anti-tagged in $b\bar{b}g$ events, by identifiying $b$ quark jets with high purities. Unbiased quark jets came from events $q\bar{q}γ$ with two jets plus one

R. Loll

The volume operator is an important kinematical quantity in the non-perturbative approach to four-dimensional quantum gravity in the connection formulation. We give a general algorithm for computing its spectrum when acting on four-valent spin network states, evaluate some of the eigenvalue formulae explicitly, and discuss the role played by the Mandelstam c

Mathias Trucks

It is a well known fact that quantum fields on Minkowski spacetime are correlated for each pair of spacetime regions. In Robertson-Walker spacetimes there are spacelike separated regions with disjoint past horizons but the absence of correlations in that case was never proved. We derive in this paper formulae for correlations of quantum fields on Robertson-W

R. J. Bursill, F. Gode

We adapt White's density matrix renormalisation group (DMRG) to the direct study of critical phenomena. We use the DMRG to generate transformations in the space of coupling constants. We postulate that a study of density matrix eigenvalues leads to a natural identification of renormalised blocks, operators and Hamiltonians. We apply the scheme to the pha

R. J. Bursill, G. A. Gehring, D. J. J. Farnell, J. B. Parkinson

We study the $T=0$ frustrated phase of the $1D$ quantum spin-$\frac 12$ system with nearest-neighbour and next-nearest-neighbour isotropic exchange known as the Majumdar-Ghosh Hamiltonian. We first apply the coupled-cluster method of quantum many-body theory based on a spiral model state to obtain the ground state energy and the pitch angle. These results ar

Ben Dorman

I review aspects of the evolution of horizontal branch (HB) stars. I start by discussing current topics in the study of HB stellar evolution, including a brief review of the main determinants of the structure of low-mass core helium burning stars and of HB morphology. I describe the `first' and `second' parameter effects on HB morphology, and attempt

Janusz Kaluzny, Wojciech Krzeminski, Beata Mazur

We report results of photometric monitoring of the NGC 2243 field in V and $I$ filters. Two W~UMa-type systems and three detached eclipsing binaries were discovered. Both contact systems are likely members of the cluster. One of detached binaries - variable V1 - has a period P=1.188 day. This variable is located at the cluster's turnoff in the color-magn

Ortwin Gerhard, Joseph Silk

The dark matter in the halos of galaxies may well be baryonic, and much of the mass within them could be in the form of clusters of substellar objects within which are embedded cold gas globules. Such halos might play an active role in galaxy formation and evolution.

D. S. Womble, W. L. W. Sargent, R. S. Lyons

For the purpose of studying the properties of heavy-elements associated with the Lyman-$α$\ forest, we observed the gravitational lens Q1422+2309. We used the HIRES instrument on the W.M. Keck telescope to obtain a high-resolution, very high signal-to-noise spectrum of this z=3.63 quasar; the spectrum covers wavelengths from below Lyman-$β$\ up to the C IV e

C. M. Newman, D. L. Stein

We present a coherent approach to the competition between thermodynamic states in spatially inhomogeneous systems, such as the Edwards-Anderson spin glass with a fixed coupling realization. This approach explains and relates chaotic size dependence, ``dispersal of the metastate'', and for replicas: non-independence, symmetry breaking, and overlap (no

Geng Xu

Let C be a smooth cubic curve in the complex projective plane. We show that for every positive integer k, there are only finite number of rational curves of degree k each intersects the cubic C at exactly one point. The number of such rational curves is known when k is 1, as a smooth cubic has 9 flexes points. This number seems to be closely related to the n

C. Alvarez, R. B. Mann

We investigate the possibility of testing of the Einstein Equivalence Principle (EEP) using measurements of anomalous magnetic moments of elementary particles. We compute the one loop correction for the $g-2$ anomaly within the class of non metric theories of gravity described by the \tmu formalism. We find several novel mechanisms for breaking the EEP whose

N. Provatas, T. Ala-Nissila, M. J. Alava

We study the properties of 2D fibre clusters and networks formed by deposition processes. We first examine the growth and scaling properties of single clusters. We then consider a network of such clusters, whose spatial distribution obeys some effective pair distribution function. In particular, we derive an expression for the two-point density autocorrelati

J. Röhler

Metal-oxygen complexes containing Cu,- Tl-, Hg-, Bi- and Pb-cations are electronically active in superconducting copper-oxides by stabilizing single phases with enhanced $T_c$, whereas other metal-oxygen complexes deteriorate copper-oxide superconductivity. Cu, Tl, Hg, Bi, Pb in their actual oxidation states are closed shell $d^{10}$ or inert $s^2$ pair ions

Guido Magnano

Current generalizations of the classical Einstein-Hilbert Lagrangian formulation of General Relativity are reviewed. Some alternative variational principles are known to reproduce Einstein's gravitational equations, and should therefore be regarded as equivalent descriptions of the same physical model, while other variational principles ("Scalar-tens

Gerard van der Geer, Marcel van der Vlugt

In this paper we give several methods to construct curves over finite fields with many points and illustrate this with examples of the results.

Florin Radulescu

Let $\G$ be any cocompact, discrete subgroup of $\pslr$. In this paper we find estimates for the predual and the uniform Banach space norms in the von Neumann algebras associated with the Berezin' s quantization of a compact Riemann surface $\Bbb D/\G$. As a corollary, for large values of the deformation parameter $1/h$, these von Neumann algebras are isomor

F. Vaca

An extensive analysis was performed on 8.0 pb-1 of dimuon data produced in pi- - A collisions at 515 GeV/c to search for Lambda_b events in the decay channel Lambda_b --> J/psi Lambda^0, with J/psi --> mu^+ mu^- and Lambda^0 --> p pi^- (and for the conjugate reactions). The data was collected by the Fermilab fixed target experiments E672 and E706. Several cu

H. Barnum, C. M. Caves, C. A. Fuchs, R. Jozsa

We show that, given a general mixed state for a quantum system, there are no physical means for {\it broadcasting\/} that state onto two separate quantum systems, even when the state need only be reproduced marginally on the separate systems. This result generalizes and extends the standard no-cloning theorem for pure states.

B. L. G. Bakker, M. I. Polikarpov, A. I. Veselov

The time evolution of a many-fermion system can be described by a Green's function corresponding to an effective potential, which takes anti-symmetrization of the wave function into account, called the Pauli-potential. We show that this idea can be combined with the Green's Function Monte Carlo method to accurately simulate a system of many non-relat

Q. A. Turchette, C. J. Hood, W. Lange, H. Mabuchi

Measurements of the birefringence of a single atom strongly coupled to a high-finesse optical resonator are reported, with nonlinear phase shifts observed for intracavity photon number much less than one. A proposal to utilize the measured conditional phase shifts for implementing quantum logic via a quantum-phase gate (QPG) is considered. Within the context

G. Harris, G. Jungman

We comment on an earlier paper of M. Gleiser, regarding mechanisms of first-order phase transitions.

S. F. Hassan

We study non-local realizations of extended worldsheet supersymmetries and the associated space-time supersymmetries which arise under a T-duality transformation. These non-local effects appear when the supersymmetries do not commute with the isometry with respect to which T-duality is performed.

V. G. Ksenzov

The vacuum energy density is calculated for the $O(N)$ nonlinear sigma models in two dimensions. To obtain $\varepsilon_{vac}$ we assume that each point of the space in which non-perturbative f\/ields are determined can be replaced by a sphere $S^2$ having a small radius $r$ which approaches zero at the very end of the calculation. This assumption allows to

Romain Attal

I build $N=1$ superstrings in $\Bbb R^4$ out of purely geometric bosonic data. The world-sheet is a bilayer of uniform thickness and the $2D$ supercharge vanishes in a natural way.

A. Dabholkar, J. P. Gauntlett, J. A. Harvey, D. Waldram

Supersymmetric closed string theories contain an infinite tower of BPS-saturated, oscillating, macroscopic strings in the perturbative spectrum. When these theories have dual formulations, this tower of states must exist nonperturbatively as solitons in the dual theories. We present a general class of exact solutions of low-energy supergravity that correspon

E. J. Martinec, N. P. Warner

The holomorphic prepotential of ultraviolet finite N=2 supersymmetric gauge theories is obtained by a partial twisting of N=1 gauge theory in six dimensions, compactified on $\IR^4\timesT^2$. We show that Ward identities for the conserved chiral $\R$-symmetry in these theories generate a set of constraints on the correlation functions of chiral ring operator

M. Benmerrouche, G. Orlandini, T. G. Steele

Making use of QCD sum rules a lower bound is found which relates the electromagnetic polarizability $α_{_E}$ and mean-square radius $\langle r_π^2\rangle$ of charged pions through the intrinsic polarizability $\tildeα_{_E}= α_{_E}-α\langle r_π^2\rangle/(3M_π)$. We find that if present constraints on the QCD continuum (duality) threshold are accepted, this lo

A. V. Radyushkin

It is demonstrated in several exclusive processes involving the pion that a local quark-hadron duality prescription is equivalent to using an effective $ \bar q q $ (two-body) light-cone wave function $Ψ^{(LD)}(x,k_{\perp})$ for the pion. This wave function models soft dynamics of all higher $\bar qG \ldots G q $ Fock components of the standard light-cone ap

S. Chernyshev, I. Zahed

We analyze the $γγ\to π^0π^0$ and $γγ\to π^+π^-$ reactions using the master formula approach to chiral symmetry breaking. The pertinent vacuum correlators are estimated at tree level, and the results are compared with one- and two-loop chiral perturbation theory. The Compton scattering amplitude and the pion polarizabilities are also discussed.

A. V. Radyushkin, R. T. Ruskov

We develop a QCD sum rule analysis of the form factor $F_{γ^*γ^*π^0}(q^2,Q^2)$ in the region where virtuality of one of the spacelike photons is small $q^2 \ll 1 GeV^2$ while another is large: $Q^2 \gapprox 1 GeV^2$. We construct the operator product expansion suitable for this kinematic situation and obtain a QCD sum rule for $F_{γ^*γ^*π^0}(0,Q^2)$. Our res

M. V. Ramana

Several proposals for dynamical electroweak symmetry breaking and fermion mass generation involve strong gauge interactions with a characteristic scale of a few hundred GeV. The detection of the glueballs which should occur in such models would be a indication of the non-Abelian nature of the gauge theories operating at this scale. We discuss signatures for

J. H. Kühn, E. Mirkes, M. Finkemeier

We review current issues in exclusive semileptonic tau decays. We present the formalism of structure functions, and then discuss predictions for final states with kaons, for decays into four pions and for radiative corrections to the decay into a single pion. Implications for testing the standard model at low energies are discussed.

Suraj N. Gupta, James M. Johnson

We have investigated $B_c$ spectroscopy with the use of a quantum-chromodynamic potential model which was recently used by us for the light-heavy quarkonia. We give our predictions for the energy levels and the $E$1 transition widths. We also find, rather surprisingly, that although $B_c$ is not a light-heavy system, the heavy quark effective theory with the

J. Lopez, D. Nanopoulos

In this Lecture we first review the basic properties that make flipped SU(5) a very economical and well motivated unified model, including some recent developments regarding the prediction for $α_s$ and new implications for proton decay. Then we sketch the derivation of flipped SU(5) from strings, stressing some new results concerning the cosmological consta

G. G. Blado, T. K. Kuo

A supersymmetric $Sp_{L}(6) \times U_{Y}(1)$ model (SUSY $Sp(6)$) is proposed as an extension of the standard electroweak model. The model is applied in a phenomenological study of $B^{0}_{d} \bar{B}^{0}_{d}$ mixing. It is found that the supersymmetric (SUSY) partner $\tilde{z}^{\prime}$ of the extra $Z^{\prime}$ can significantly cancel the other contributi

B. L. Ioffe

The uncertainties in the perturbative and higher twist corrections to the sum rules for $Γ_{p,n}$ are analyzed. The theoretical predictions for $Γ_{p,n}$ are compared with the whole set of experimental data and the restrictions on theoretical uncertainties was obtained. Suggestions for future experiments are given.

J. Kwiecinski, A. D. Martin, P. J. Sutton

We study the perturbative QCD description of the HERA measurements of $F_2 (x, Q^2)$ using a gluon distribution that is obtained from an evolution incorporating angular ordering of the gluon emissions, and which embodies both GLAP and BFKL dynamics. We compare the predictions with recent HERA data for $F_2$. We present estimates of the charm component $F_2^c

R. Engel, A. Schiller, V. G. Serbo

We consider coherent electromagnetic processes for colliders with short bunches, in particular the coherent bremsstrahlung (CBS). CBS is the radiation of one bunch particles in the collective field of the oncoming bunch. It can be a potential tool for optimizing collisions and for measuring beam parameters. A new simple and transparent method to calculate CB

Levan Surguladze, Davison E. Soper

We study the perturbative QCD series for the hadronic width of the Z boson. We sum a class of large ``pi^2 terms'' and reorganize the series so as to minimize ``renormalon'' effects. We also consider the renormalization scheme-scale ambiguity of the perturbative results. We find that, with three nontrivial known terms in the perturbative expa

D. Makovoz, G. A. Miller

Spectral density in the pseudoscalar and vector channels is extracted from the SU(2) lattice quenched data. It is shown to consist of three sharp poles within the energy range accessible on the lattice.

Seyong Kim

We discuss \(B_c\) mass (1S state) and decay constant \(f_{B_c}\) calculated by lattice non-relativistic quantum chromodynamcs(NRQCD) method. In leading order of \(v^2\), we found that \(M_{B_c} = 6.33(2)\) GeV and \(f_{B_c} = 395(2)\) MeV where the error bar is the statistical error only. Using these values, we estimate QCD effects to leptonic decay width o

Jean-Philippe Bouchaud, Leticia Cugliandolo, Jorge Kurchan, Marc Mézard

We discuss the general link between mode-coupling like equations (which serve as the basis of some recent theories of supercooled liquids) and the dynamical equations governing mean-field spin-glass models, or the dynamics of a particle in a random potential. The physical consequences of this interrelation are underlined. It suggests to extend the mode-coupl

E. Ben-Naim, L. Frachebourg, P. L. Krapivsky

We investigate coarsening and persistence in the voter model by introducing the quantity $P_n(t)$, defined as the fraction of voters who changed their opinion n times up to time t. We show that $P_n(t)$ exhibits scaling behavior that strongly depends on the dimension as well as on the initial opinion concentrations. Exact results are obtained for the average

Rodolfo Cuerno, Hernan A. Makse, Silvina Tomassone, Stephen T. Harrington

Surfaces eroded by ion-sputtering are sometimes observed to develop morphologies which are either ripple (periodic), or rough (non-periodic). We introduce a discrete stochastic model that allows us to interpret these experimental observations within a unified framework. We find that a periodic ripple morphology characterizes the initial stages of the evoluti

Ari Buchalter, Marc Kamionkowski, R. Michael Rich

If the objects responsible for gravitational microlensing (ML) of Galactic-bulge stars are faint dwarfs, then blended light from the lens will distort the shape of the ML light curve and shift the color of the observed star during the event. The resolution in current surveys is not accurate enough to observe this effect, but it should be detected with freque

J. B. Hutchings

Images of IRAS galaxies with a range of IR properties are examined for bright knots, both within and outside the galaxy. These are found almost exclusively in galaxies with steep IR spectra, but over a wide range of IR luminosity, and usually without strong nuclear activity. In most cases, the knots are likely to be star-formation induced by tidal interactio

Ralf Klessen, Andreas Burkert

This work considers the idea of massive black holes being the constituents of the Galactic dark matter halo. It constrains the maximum black hole mass to $\mbh \sil 5 \times 10^4 \msun$ by examining their influence on the population of globular clusters in our Milky Way. In the adopted halo model, globular clusters are exposed to constant bombardment of halo

James R. Murray

We numerically study the precessing disk model for superhump in the SU~UMa subclass of cataclysmic variables, using a two dimensional SPH code specifically designed for thin disk problems. Two disk simulations for a binary with mass ratio $q=\frac{3}{17}$ (similar to OY~Car) are performed, in order to investigate the Lubow (1991 a,b) tidal resonance instabil

Cathie Clarke, Dave Syer

We show that outside-in disc instabilities, which can produce rapid-\null rise FU Orionis outbursts in T~Tauri systems, are a natural consequence of the existence of protoplanetary protostellar companions. The \pcomp{} would be formed through gravitational instability on a dynamical timescale ($\sim 10^5\y$), and provided it was formed at less than a few \AU

Juan Garcia-Bellido, David Wands

We study the metric perturbations produced during inflation in models with two scalar fields evolving simultaneously. In particular, we emphasize how the large-scale curvature perturbation $ζ$ on fixed energy density hypersurfaces may not be conserved in general for multiple field inflation due to the presence of entropy as well as adiabatic fluctuations. We