February 1998 arXiv papers — page 5

Ichiro Oda

We show that the super D-string action is exactly equivalent to the IIB Green-Schwarz superstring action with some "theta term" in terms of the path integral. Since the "theta term" imposes the Gauss law constraint on the physical state but contributes to neither the mass operator nor the constraints associated with the kappa symmetry and the

Bo-yu Hou, Wen-li Yang

We demonstrate that in a certain gauge the elliptic Ruijsenaars-Shneider model with N=2 admits a nondynamical r-matrix structure and the corresponding classical r-matrix is the same as that of its non-relativistic counterpart (Calogero-Moser model) in the same gauge.The relation between our (classical)Lax operator and the Lax operator given by Ruijsenaars is

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

Acausal features of quantum electrodynamic processes are discussed. While these processes are not present for the classical electrodynamic theory, in the quantum electrodynamic theory, acausal processes are well known to exist. For example, any Feynman diagram with a ``loop'' in space-time describes a ``particle'' which may move forward in ti

Bit-Shun Tam, Hans Schneider

For an $n \times n$ nonnegative matrix $P$, an isomorphism is obtained between the lattice of initial subsets (of ${1,...,n}$) for $P$ and the lattice of $P$-invariant faces of the nonnegative orthant $\IR^{n}_{+}$. Motivated by this isomorphism, we generalize some of the known combinatorial spectral results on a nonnegative matrix that are given in terms of

Ludwig Elsner, Daniel Hershkowitz, Hans Schneider

An upper bound on operator norms of compound matrices is presented, and special cases that involve the $\ell_1$, $\ell_2$ and $\ell_\infty$ norms are investigated. The results are then used to obtain bounds on products of the largest or smallest eigenvalues of a matrix.

Youliang Tian, Weiping Zhang

We extend our earlier work in [TZ1], where an analytic approach to the Guillemin-Sternberg conjecture [GS] was developed, to cases where the Spin$^c$-complex under consideration is allowed to be further twisted by certain natural exterior power bundles. The main result is a weighted quantization formula in the presence of commuting Hamiltonian actions. The c

Dong-Sheng Du, Zheng-Tao Wei

The space-like penguin contributions to branching ratios and CP asymmetries in charmless decays of $B_{c}$ to two pseudoscalar mesons are studied using the next-to-leading order low energy effective Hamiltonian and factorization approximation. Both the gluonic penguin and the electroweak penguin diagrams are considered. In addition the annihilation diagram c

M. K. Suleimanov, O. B. Abdinov, A. I. Anoshin, J. Bogdanowicz

The ideas that extreme states of nuclear matter arise in events with total dis- integration of nuclei (TDN) and as these states arise, the properties of events qualitatively change with the number of protons emitted from the nucleus Q,star- ting from its certain boundary numbe Q*,are used in this paper for the experi- mentally search for extreme states of nu

Tapan K. Nayak

Disoriented Chiral Condensates (DCC) have been predicted to form in high energy heavy ion collisions where the approximate chiral symmetry of QCD has been restored. This leads to large imbalances in the production of charged to neutral pions. Sophisticated analysis methods are being developed to disentangle DCC events out of the large background of events wi

Bozhidar Z. Iliev

We discuss and investigate the problem of existence of metric-compatible linear connections for a given space-time metric which is, generally, assumed to be semi-pseudo-Riemannian. We prove that under sufficiently general conditions such connections exist iff the rank and signature of the metric are constant. On this base we analyze possible changes of the s

K. Nishikido, C. Thessieu, G-q. Zheng, Y. Kitaoka

We report the NQR study on the pressure-induced paramagnetic state in the antiferromagnetic (AF) intermetallic compound YMn$_2$ with the Néel temperature T_N=100 K at ambient pressure. From the $T$ variation of the nuclear spin-lattice relaxation rate, $^{55}(1/T_1)$ of $^{55}$Mn above the critical pressure of 4 kbar, the spin fluctuation feature is found to

M. Boettcher, E. P. Liang

We investigate the effect of inverse-Compton scattering of flares of soft radiation in different geometries of a hot, Comptonizing region and a colder accretion disk around a solar-mass black hole. The photon-energy dependent light curves, their Fourier transforms, power spectra and Fourier-period dependent time lags of hard photons with respect to softer ph

F. La Franca, S. Cristiani

An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3<z<2.2) have been selected over 555 deg^2 with 15<B<18.75. For B<16.4 the QSO surface density turns out to be a factor 2.2 higher than what measured by the PG survey, corresponding to a surface density of 0.013+/-.006 deg^{-2}. If the Edinburgh

F. La Franca, P. Andreani, S. Cristiani

The evolution of QSO clustering is investigated with a new sample of 388 QSOs with 0.3<z<2.2, B<20.5 and M_B<-23. Evidence is found for an increase of the clustering amplitude with increasing redshift. These measurements allow to further distinguish among the various physical scenarios proposed to interpret the QSO phenomenon. A single population model is in

M. Alishahiha

We study two dimensional $N=(4,4)$ supersymmetric gauge theories with various gauge groups and various hypermultiplets in the fundamental as well as bi-fundamental and adjoint representations. They have &#34; mirror theories &#34; which become equivalent to them at the strong coupling. The theory with one fundamental and one adjoint has a Higgs branch which

L. Stodolsky

We point out that many wavepacket discussions for the coherence properties of particle beams are unnecessary since they deal with stationary sources; and when the problem is stationary, essentially all information is in the energy spectrum. This recognition allows a simple answer to a number of long-debated points, usually framed in terms of &#34;the length

S. M. Sergeev

Quantum 3D R-matrix in the classical (i.e. functional) limit gives a symplectic map of dynamical variables. The corresponding 3D evolution model is considered. An auxiliary problem for it is a system of linear equations playing the role of the monodromy matrix in 2D models. A generating function for the integrals of motion is constructed as a determinant of

J. F. Carinena, G. Marmo, J. Nasarre

Group theoretical methods are used to study some properties of the Riccati equation, which is the only differential equation admitting a nonlinear superposition principle. The Wei-Norman method is applied to obtain the associated differential equation in the group $SL(2,R)$. The superposition principle for first order differential equation systems and Lie-Sc

Fritz Gesztesy, Nigel J. Kalton, Konstantin A. Makarov, Eduard Tsekanovskii

We consider operator-valued Herglotz functions and their applications to self-adjoint perturbations of self-adjoint operators and self-adjoint extensions of densely defined closed symmetric operators. Our applications include model operators for both situations, linear fractional transformations for Herglotz operators, results on Friedrichs and Krein extensi

Z. Chacko, R. N. Mohapatra

We show that in a large class of supersymmetric $SU(2)_L\times SU(2)_R\times SU(4)_c$ models with the see-saw mechanism for neutrino masses and an R-parity conserving vacuum, there are diquark Higgs bosons with masses ($M_{qq}$) near the weak scale even though the scale of $SU(2)_R\times SU(4)_c$ symmetry breaking is around $10^{10}$ GeV. This happens becaus

J. Kwiecinski, B. Ziaja

The proton spin dependent structure function $g_1^p$ is analysed using the unified scheme incorporating both Altarelli-Parisi evolution and the double $ln^2(1/x)$ effects at low $x$. The latter are found to be very important in the region of $x$ which can possibly be probed at HERA. Predictions for the polarized gluon distribution $ΔG(x)$ at low $x$ are also

Pyungwon Ko

Recent developments in heavy quarknoium physics are reviewed in brief, including (i) nonrelativistic QCD(NRQCD), (ii) the importance of color-octet $(Q\bar{Q})$ components in the decay and the production of a physical heavy quarkonium state, (iii) limitation of the NRQCD factorization and (iv) the double humps in the $ππ$ spectrum in the decay $Υ(3S) \to Υ(1

V. K. Petrov

Spatial string tension is computed in finite temperature gluodynamics on asymmetric lattices in a spherical model approximation. Conditions of scaling behavior are specified. Discrepancies with a standard renormalisation procedure are discussed.

V. R. Krym

We give a short historical review of early Kaluza-Klein theories. We study various causal structures on manifolds, especially those which cannot be described by a metric tensor with signature (+---). The smooth structure (atlas) on a manifold is found to be related with its causal structure.

E. G. Timoshenko, Yu. A. Kuznetsov, K. A. Dawson

In this paper we extend the Gaussian self-consistent method to permit study of the equilibrium and kinetics of conformational transitions for heteropolymers with any given primary sequence. The kinetic equations earlier derived by us are transformed to a form containing only the mean squared distances between pairs of monomers. These equations are further ex

E. Krotscheck, R. Zillich

We develop a first principles, microscopic theory of impurity atom scattering from inhomogeneous quantum liquids such as adsorbed films, slabs, or clusters of He-4. The theory is built upon a quantitative, microscopic description of the ground state of both the host liquid as well as the impurity atom. Dynamic effects are treated by allowing all ground-state

S. Alam, M. Nasir Khan, Jauhar Ali

The Hubbard Hamiltonian and its variants/generalizations continue to dominate the theoretical modelling of important problems such as high temperature superconductivity. In this note we identify the set of relevant operators for the Hubbard Hamiltonian with a magnetic field term.

S. V. Vyshenski, U. Zeitler, R. J. Haug

Considering a double-barrier structure formed by a silicon quantum dot covered by natural oxide, we derive simple conditions for the conductance of the dot to become a step-like function of the number of doping atoms inside the dot, with negligible dependence on the actual position of the dopants. The found conditions are feasible in experimentally available

Tatsuo Shibata, Kunihiko Kaneko

Collective behavior is studied in globally coupled maps. Several coherent motions exist, even in fully desynchronized state. To characterize the collective behavior, we introduce scaling transformation of parameter, and detect the tongue-like structure of collective motions in parameter space. Such collective motion is supported by the separation of time sca

V. Celebonovic

An analytical expression for Fermi-Dirac integrals of arbitrary order is presented,and its applicability in obtaining the EOS of a degenerate,non-relativistic,Fermi gas is discussed.

J. Isern, E. Garcia-Berro, M. Hernanz, R. Mochkovitch

Halo white dwarfs can provide important information about the properties and evolution of the galactic halo. In this paper we compute, assuming a standard IMF and updated models of white dwarf cooling, the expected luminosity function, both in luminosity and in visual magnitude, for different star formation rates. We show that a deep enough survey (limiting

Edward Witten

Recently, it has been proposed by Maldacena that large $N$ limits of certain conformal field theories in $d$ dimensions can be described in terms of supergravity (and string theory) on the product of $d+1$-dimensional $AdS$ space with a compact manifold. Here we elaborate on this idea and propose a precise correspondence between conformal field theory observ

Mark Wardle

I examine the role of dust grains in determining the structure of steady, cold, oblique C-type shocks in dense molecular gas. Gas pressure, the inertia of the charged components, and changes in ionisation are neglected. The grain charge and rate coefficients for electron-neutral and grain-neutral elastic scattering are assumed constant at values appropriate

Niclas Wyllard

We compactify M-theory in the Horava-Witten formulation on S^1/Z_2 \times K3 \times T^2. Focusing on the moduli-space of vector multiplets of the resulting four-dimensional N=2 theory, we determine the prepotential as an expansion in two dimensionless parameters which both scale as κ^{2/3}. We determine the prepotential completely to relative order κ^{4/3} a

José F. Carinena, Jesús Clemente-Gallardo, Eduardo Follana, José M. Gracia-Bondía

We address one of the open problems in quantization theory recently listed by Rieffel. By developping in detail Connes&#39; tangent groupoid principle and using previous work by Landsman, we show how to construct a strict, flabby quantization, which is moreover an asymptotic morphism and satisfies the reality and traciality constraints, on any oriented Riema

Miquel Dorca

We study the quantization of a scalar field on a classical background given by the Szekeres Class of solutions, which represent the collision of two gravitational plane waves with constant polarization. These solutions consist of two approaching gravitational plane waves moving in a flat background and an interaction region which always contains a curvature

S. L. Dubovsky, P. G. Tinyakov

We show that ``top-down&#39;&#39; mechanisms of Ultra-High Energy Cosmic Rays which involve heavy relic particle-like objects predict Galactic anisotropy of highest energy cosmic rays at the level of minimum $\sim 20%$. This anisotropy is large enough to be either observed or ruled out in the next generation of experiments.

Yu. L. Dokshitzer, A. Lucenti, G. Marchesini, G. P. Salam

We perform the two-loop analysis of the 1/Q power corrections to jet-shape variables. This step is necessary for producing reliable theoretical predictions for the relative magnitudes of genuine confinement effects. We show that the rescaling factor recently derived for the thrust case (the Milan factor) remains the same for the class of observables which in

Kirill Melnikov, Alexander Yelkhovsky

We calculate the next-to-next-to-leading order correction to the cross section for top quark pair production in e+e- annihilation in the threshold region, resumming all O [ (alpha_s/beta)^n (alpha_s^2, beta^2, alpha_s beta) ] terms of perturbation series. We find that the magnitude of the NNLO correction is comparable to the size of the NLO corrections.

Philippe Jacquod

The spectral properties of a disordered system with few interacting three-dimensional spinless fermions are investigated. We show the existence of a critical spacings distribution which is invariant upon increase of the system size, but strongly depends on the number of particles. At the critical point, we report a substantial decrease of the degree of level

E. Sh. Mamasakhlisov, V. F. Morozov, M. S. Shahinian

We study random heteropolymer chain with gaussian distribution of kinds of monomers. The long-range correlations between kinds of monomers were introduce. The mean-field analysis of such heteropolymer indicates the existence of infinite energetic barrier between heteropolymer random coil and frozen states. Thus, the frozen state is kinetically unavailable fo

L. Andrianopoli, R. D&#39;Auria, S. Ferrara, M. A. Lledo

We consider the problem of extremizing the tension for BPS strings in D=6 supergravities with different number of supersymmetries. General formulae for fixed scalars and a discussion of degenerate directions is given. Quantized moduli, according to recent analysis, are supposed to be related to conformal field theories which are the boundary of three dimensi

Cheuk-Yin Wong, Hui Wang

We calculate the photon production cross section arising from the hard scattering of partons in nucleon-nucleon collisions by taking into account the intrinsic parton transverse momentum distribution and the next-to-leading-order contributions. As first pointed out by Owens, the inclusion of the intrinsic transverse momentum distribution of partons leads to

M. Disertori, V. Rivasseau

We build the two dimensional Gross-Neveu model by a new method which requires neither cluster expansion nor discretization of phase-space. It simply reorganizes the perturbative series in terms of trees. With this method we can for the first time define non perturbatively the renormalization group differential equations of the model and at the same time cons

M. Boettcher, M. Pohl, R. Schlickeiser

Models of relativistic jets filled with ultrarelativistic pair plasma are very successful in explaining the broadband radiation of $γ$-ray blazars. Assuming that the initial injection and cooling of ultrarelativistic pair plasma in an AGN jet has occurred, producing the observed high-energy $γ$-ray radiation, we investigate the further evolution of the pair

M. Magliocchetti, S. J. Maddox, O. Lahav, J. V. Wall

We investigate the large-scale clustering of radio sources in the FIRST 1.4-GHz survey by analysing the distribution function (counts in cells). We select a reliable sample from the the FIRST catalogue, paying particular attention to the problem of how to define single radio sources from the multiple components listed. We also consider the incompleteness of

R. Horvat

We consider the unconventional way to interpret the current data on solar neutrino oscillations as derived recently by Halprin and Leung from a string model based on the existence of the string dilaton field which remains massless in the low-energy world. The equivalence principle violation entailed by the existence of a massless dilaton may then produce neu

Rachel S. Somerville, Joel R. Primack

Using semi-analytic models of galaxy formation, we investigate galaxy properties such as the Tully-Fisher relation, the B and K-band luminosity functions, cold gas contents, sizes, metallicities, and colours, and compare our results with observations of local galaxies. We investigate several different recipes for star formation and supernova feedback, includ

Karsten Flensberg

We study the transconductance for two coupled one-dimensional wires or edge states described by Luttinger liquid models. The wires are assumed to interact over a finite segment. We find for the interaction parameter $g=1/2$ that the drag rate is finite at zero temperature, which cannot occur in a Fermi-liquid system. The zero temperature drag is, however, cu

Gennady A. Koganov, Reuben Shuker

Dynamic properties of closed three level laser systems are investigated. Two schemes of pumping - $Λ$ and V - are considered. It is shown that the non-linear behavior of the photon number as a function of pump both near and far above threshold is crucially different for these two configurations. In particular, it is found that in the high pump regime laser c

P. G. Silvestrov

Eigenfunctions of 1d disordered Hamiltonian with constant imaginary vector potential are investigated. Even within the domain of complex eigenvalues the wave functions are shown to be strongly localized. However, this localization is of a very unusual kind. The logarithm of the wave function at different coordinates $x$ fluctuates strongly (just like the pos

S. Groote, J. G. Körner, K. Schilcher, N. F. Nasrallah

We present the results of a new evaluation of the running fine structure constant $α$ at the scale of the $Z$ mass in which the role of the $e^+e^-$ annihilation input data needed in this evaluation is minimized. This is achieved by reducing the weight function $M_Z^2/(s(M_Z^2-s))$ in the dispersion integral over the $e^+e^-$ annihilation data by subtracting

R. J. Bursill, R. H. McKenzie, C. J. Hamer

The one-dimensional Holstein model of spinless fermions interacting with dispersionless phonons is studied using a new variant of the density matrix renormalisation group. By examining various low-energy excitations of finite chains, the metal-insulator phase boundary is determined precisely and agrees with the predictions of strong coupling theory in the an

S. James Gates,, Tomoko Kadoyoshi, Shin&#39;ichi Nojiri, Sergei D. Odintsov

We consider N=1 two-dimensional (2d) dilatonic supergravity (SG), 2d dilatonic SG obtained by dimensional reduction from N=1 four-dimensional (4d) SG, N=2 2d dilatonic SG and string-inspired 4d dilatonic SG. For all the theories, the corresponding action on a bosonic background is constructed and the interaction with $N$ (dilatonic) Wess-Zumino (WZ) multiple

Yoshio Koide

Stimulated by a universal seesaw mass matrix model which can successfully give quark masses and CKM matrix elements in terms of charged lepton masses, the evolution of the seesaw mass matrices is investigated. Especially, an investigation is made as to whether the evolution can constrain the necessary intermediate scales in these types of models and its viab

Daniel Boyanovsky, Hector J. de Vega, Richard Holman, S. Prem Kumar

The real time evolution of field condensates with soft length scales k^{-1}>(eT)^{-1} is solved in hot scalar electrodynamics, with a view towards understanding relaxational phenomena in the QGP and the electroweak plasma. We find that transverse gauge invariant non-equilibrium expectation values of fields relax via {\em power laws} to asymptotic amplitudes

F. delduc, L. Gallot

The Drinfeld-Sokolov construction of integrable hierarchies, as well as its generalizations, may be extended to the case of loop superalgebras. A sufficient condition on the algebraic data for the resulting hierarchy to be invariant under supersymmetry transformation is given. The method used is a construction of the hierarchies in superspace, where supersym

Wojciech H. Zurek

The environment -- external or internal degrees of freedom coupled to the system -- can, in effect, monitor some of its observables. As a result, the eigenstates of these observables decohere and behave like classical states: Continuous destruction of superpositions leads to environment-induced superselection (einselection). Here I investigate it in the cont

Alice Sinatra, Yvan Castin

In the absence of losses the phase of a Bose-Einstein condensate undergoes collapses and revivals in time due to elastic atomic interactions. As experiments necessarily involve inelastic collisions, we develop a model to describe the phase dynamics of the condensates in presence of collisional losses. We find that a few inelastic processes are sufficient to

L. Tiator, G. Knoechlein, C. Bennhold

We present a combined analysis of the new eta photoproduction data for total and differential cross sections, target asymmetry and photon asymmetry. Using basic assumptions, this allows a model-independent extraction of the $E_{2-}$ and $M_{2-}$ multipoles as well as resonance parameters of the $D_{13}(1520)$ state. At higher energy, we show that the photon

J. Denschlag, L. Tiator, D. Drechsel

We have investigated the processes N($π$, $π$)N and N($π$, $η$)N close to eta threshold using a simple, nonrelativistic Lee model which has the advantage of being analytically solvable. It is then possible to study the Riemann sheets of the S-matrix and the behavior of its resonance poles especially close to threshold. A theoretical simulation of the experim

H. Arenhoevel

After a brief introduction into the basic ingredients of electroweak theory as a spontaneously broken local, non-Abelian gauge symmetry, the general properties of the electromagnetic current and two-photon operators are discussed. The specific forms of vector and axial one-nucleon currents are given, together with lowest order $π$ meson exchange and isobar c

B. C. Clark, R. J. Furnstahl, L. Kurth Kerr, John Rusnak

Recently developed chiral effective field theory models provide excellent descriptions of the bulk characteristics of finite nuclei, but have not been tested with other observables. In this work, densities from both relativistic point-coupling models and mean-field meson models are used in the analysis of meson-nucleus scattering at medium energies. Elastic

Martin Scharlemann, Jennifer Schultens

The Heegaard genus g of an irreducible closed orientable 3-manifold puts a limit on the number and complexity of the pieces that arise in the Jaco-Shalen-Johannson decomposition of the manifold by its canonical tori. For example, if p of the complementary components are not Seifert fibered, then p < g. This result generalizes work of Kobayashi. The Heegaard

Ulrich Bunke

Using the higher analytic torsion form of Bismut and Lott we construct a characteristic class for smooth sphere bundles. We calculate this class in the case where the sphere bundle comes from a complex vector bundle. Related to these characteristic classes we define nontrivial continuous group cohomology classes of the diffeomorphism group of odd dimensional

Adrian Langer

We prove that the bicanonical system on a surface of general type with K^2=4 has no base components and describe clusters contracted by 4K_X for a numerical Godeaux surface and 3K_X for a numerical Campedelli surface.

Adrian Langer

We prove Reider type criterions for k-jet spannedness and k-jet ampleness of adjoint bundles for surfaces with at most rational singularities. Moreover, we prove that on smooth surfaces [n(n+4)/4]-very ampleness implies n-jet ampleness.

Burt Totaro

We define the Chow ring of the classifying space of a linear algebraic group. In all the examples where we can compute it, such as the symmetric groups and the orthogonal groups, it is isomorphic to a natural quotient of the complex cobordism ring of the classifying space, a topological invariant. We apply this to get torsion information on the Chow groups o

Oded Kenneth, Shmuel Nussinov

A new version of the Casimir effect where the two plates conduct in specific, different, directions is considered. By direct functional integration the evaluation of the Casimir energy as a function of the angle between the conduction directions is reduced to quadratures. Other applications of the method and a magnetic Casimir variant are mentioned.

A. Campbell-Smith

The composite operator effective potential is compared with the conventional Dyson-Schwinger method as a calculational tool for (2+1)-dimensional quantum electrodynamics. It is found that when the fermion propagator ansatz is put directly into the effective potential, it reproduces exactly the usual gap equations derived in the Dyson-Schwinger approach.

Nathan Seiberg

An overview of supersymmetry and its different applications is presented. We motivate supersymmetry in particle physics. We then explain how supersymmetry helps us analyze field theories exactly, and what dynamical lessons these solutions teach us. Finally, we describe how supersymmetry is used to derive exact results in string theory. These results have led

Burkhard Kleihaus, Jutta Kunz, Abha Sood, Marion Wirschins

SU(4) Einstein-Yang-Mills theory possesses sequences of static spherically symmetric globally regular and black hole solutions. Considering solutions with a purely magnetic gauge field, based on the 4-dimensional embedding of $su(2)$ in $su(4)$, these solutions are labelled by the node numbers $(n_1,n_2,n_3)$ of the three gauge field functions $u_1$, $u_2$ a

M. Rausch de Traubenberg

After a short introduction on Clifford algebras of polynomials, we give a general method of constructing a matrix representation. This process of linearization leads naturally to two fundamental structures: the generalized Clifford algebra (GCA) and the generalized Grassmann algebra (GGA) which are studied. Then, it is proved that if we equip the GGA with a

Ingo Gaida

Exact black hole solutions of the five dimensional heterotic $S$-$T$-$U$ model including all perturbative quantum corrections and preserving $1/2$ of $N=2$ supersymmetry are studied. It is shown that the quantum corrections yield a bound on electric charges and harmonic functions of the solutions.

Y. Tanii

Supergravities in four and higher dimensions are reviewed. We discuss the action and its local symmetries of N=1 supergravity in four dimensions, possible types of spinors in various dimensions, field contents of supergravity multiplets, non-compact bosonic symmetries, non-linear sigma models, duality symmetries of antisymmetric tensor fields and super p-bra

Kim Baskerville, Robin Michaels

The normal mode spectra of multiskyrmions play a key role in their quantisation. We present a general method capable of predicting all the low-lying vibrational modes of known minimal energy multiskyrmions. In particular, we explain the origin of the higher multipole breathing modes, previously observed but not understood. We show how these modes may be clas

Ralph Engel, T. K. Gaisser, Paolo Lipari, Todor Stanev

There are both theoretical and experimental uncertainties in using data from cosmic-ray air showers to estimate hadronic cross sections above accelerator energies. We outline these problems and compare the physics used to extract σ_{pp}^{tot} from air shower data to the widely used parameterization of the proton-proton cross section of Donnachie and Landshof

P. Langacker, J. Wang

We consider transitions between neutrinos and anti-neutrinos in laboratory experiments in five scenarios, including both helicity flipping and preserving cases.

M. Feindt

A review over recent experimental progress in the physics of the fifth quark is given.

T. van Ritbergen, A. N. Schellekens, J. A. M. Vermaseren

We present algorithms for the group independent reduction of group theory factors of Feynman diagrams. We also give formulas and values for a large number of group invariants in which the group theory factors are expressed. This includes formulas for various contractions of symmetric invariant tensors, formulas and algorithms for the computation of character

S. N. Gninenko, N. V. Krasnikov

It is shown that a new light gauge boson $X$ which might be produced in the decays of pseudoscalar mesons $π^{0}(η)\toγ+ X$ could be effectively searched for in neutrino experiments via the Primakoff effect, in the process of $X + Z\to π^{0}(η) + Z$ conversion in the external Coulomb field of a nucleus. An estimate of the $X\to π^{0}$ conversion rate for the

M. Jezabek, J. H. Kuhn, M. Peter, Y. Sumino

We include the full second-order corrections to the static QCD potential in the analysis of the ttbar threshold cross section. There is an unexpectedly large difference between the QCD potential improved by the renormalization-group equation in momentum space and the potential improved by the renormalization-group equation in coordinate space. This differenc

Aleksey I. Alekseev

We discuss whether or not &#34;freezing&#34; of the QCD running coupling constant in the infrared region is consistent with the Schwinger -- Dyson (SD) equations. Since the consistency of the &#34;freezing&#34; was not found, the conclusion is made that the &#34;analytization&#34; method does not catch an essential part of nonperturbative contributions. Proc

W. W. Buck, Richard F. Lebed

We generalize a recent model-independent form factor parameterization derived from rigorous dispersion relations to include constraints from data in the timelike region. These constraints dictate the convergence properties of the parameterization and appear as sum rules on the parameters. We further develop a new parameterization that takes into account fini

E. Laermann

Recent developements in QCD at finite temperature are reviewed. Particular emphasis is laid on results stemming from simulations which involve quarks.

Martin Lüscher

The topics covered by the lectures include Symanzik&#39;s effective continuum theory, O(a) improvement, chiral symmetry on the lattice and non-perturbative renormalization.

G. Damm, W. Kerler, V. K. Mitrjushkin

We investigate propagators in Lorentz (or Landau) gauge by Monte Carlo simulations. In order to be able to compare with perturbative calculations we use large $β$ values. There the breaking of the Z(2) symmetry turns out to be important for all of the four lattice directions. Therefore we make sure that the analysis is performed in the correct state. We disc

M. Paulini

We review the status of heavy quark physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and DO. In particular, we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B0 B0= mixing results.

Jayashree Balakrishna, Franz E. Schunck

We investigate the gravitational evolution of dark matter halos made up of a massless bosonic field. The coupled Einstein-Klein-Gordon equations are solved numerically, showing that such a boson halo is stable and can be formed under a large class of initial conditions. We also present an analytical proof that such objects are stable in the Newtonian limit.

Enzo Marinari, Carla Naitza, Francesco Zuliani

We present numerical simulations of the 4D Edwards Anderson Ising spin glass with binary couplings. Our results, in the midst of strong finite size effects, suggest the existence of a spin glass phase transition. We present a preliminar determination of critical exponents. We discuss spin glass susceptibilities, cumulants of the overlap and energy overlap pr

Haye Hinrichsen, Geza Odor

We investigate the influence of correlated initial conditions on the temporal evolution of a (d+1)-dimensional critical directed percolation process. Generating initial states with correlations <s_i*s_{i+r}>~r^(sigma-d) we observe that the density of active sites in Monte-Carlo simulations evolves as rho(t)~t^kappa. The exponent kappa depends continuously on

R. de Picciotto

A simple equivalent circuit, which describes transport properties of a Two Dimensional Electron Gas in the Fractional Quantum Hall regime is presented. The physical justifications for this equivalent circuit are discussed in the frame work of the non-interacting Composite Fermions model. Quantum Shot Noise at an arbitrary filling factor and temperature is re

Deepak Dhar, Dietrich Stauffer

We reexamine the theory of transition from drift to no-drift in biased diffusion on percolation networks. We argue that for the bias field B equal to the critical value B_c, the average velocity at large times t decreases to zero as 1/log(t). For B < B_c, the time required to reach the steady-state velocity diverges as exp(const/|B_c-B|). We propose an extra

H. H. Lee, J. M. F. Gunn

For thin films of superfluid adsorbed on a disordered substrate, we derive the equation of motion for a vortex in the presence of a random potential within a mean field (Hartree) description of the condensate. The compressible nature of the condensate leads to an effective pinning potential experienced by the vortex which is nonlocal, with a long range tail

M. Boman, R. J. Bursill

This work addresses the question of whether low-lying excitations in conjugated polymers are comprised of free charge-carriers or excitons. States are characterised as bound or unbound according to the scaling of the average particle-hole separation with system size. We critically examine other criteria commonly used to characterise states. The polymer is de

Yuri G. Rubo, M. J. Lea

The a.c. response of an unpinned and finite 2D Wigner crystal to electric fields at an angular frequency $ω$ has been calculated in the dissipative limit, $ωτ\ll 1$, where $τ^{-1}$ is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode a

P. G. Akishin, M. V. Altaisky, A. D. Budnik, V. V. Ivanov

We propose an asymmetric modification of the sand-pile-like cellular automaton for earthquake modeling. The cumulative event distribution is shown to be dependent on the asymmetry parameter.

Kunihiko Kaneko

Strength of attractor is studied by the return rate to itself after perturbations, for a multi-attractor state of a globally coupled map. It is found that fragile (Milnor) attractors have a large basin volume at the partially ordered phase. Such dominance of fragile attractors is understood by robustness of global attraction in the phase space. Change of the

J. H. Krolik

Accretion disks around black holes in which the shear stress is proportional to the total pressure, the accretion rate is more than a small fraction of Eddington, and the matter is distributed smoothly are both thermally and viscously unstable in their inner portions. The nonlinear endstate of these instabilities is uncertain. Here a new inhomogeneous equili

Philip A. Hughes, Hugh D. Aller, Margo F. Aller

We use a continuous wavelet transform to analyze more than two decades of data for the BL~Lac object OJ~287 acquired as part of the UMRAO variability program. We find clear evidence for a persistent modulation of the total flux and polarization with period $\sim 1.66$ years, and for another signal that dominates activity in the 1980s with period $\sim 1.12$