July 1998 arXiv papers — page 8

M. Toller

We study the variances of the coordinates of an event considered as quantum observables in a Poincare' covariant theory. The starting point is their description in terms of a covariant positive-operator-valued measure on the Minkowski space-time. Besides the usual uncertainty relations, we find stronger inequalities involving the mass and the centre-of-m

Fabio Sattin

A classical model of the hydrogen atom in a static electric field is studied, basing upon the work [ Hooker A. et al, {\it Phys. Rev. A}, 55 (1997) 4609 ]. In that work the electrons are supposed to move along Kepler orbits around the nucleus, while interacting with the external field. That classical model reproduces very well the true energy shift of the li

Fabio Sattin, Luca Salasnich

We study numerically collisions between protons and $H_2^+$ molecular ions at intermediate impact energies by using the Classical Trajectory Monte Carlo method (CTMC). Total and differential cross sections are computed. The results are compared with: a) the standard one electron--two nucleon scattering, and b) the quantum mechanical treatment of the $ H^{+}

A. R. de Lima, C. Moukarzel, T. J. P. Penna

A computational study of sliding blocks on inclined surfaces is presented. Assuming that the friction coefficient $μ$ is a function of position, the probability $P(λ)$ for the block to slide down over a length $λ$ is numerically calculated. Our results are consistent with recent experimental data suggesting a power-law distribution of events over a wide rang

D. Chruscinski, J. Kijowski

New, gauge-independent, second-order Lagrangian for the motion of classical, charged test particles is used to derive the corresponding Hamiltonian formulation. For this purpose a Hamiltonian description of the theories derived from the second-order Lagrangian is presented. Unlike in the standard approach, the canonical momenta arising here are explicitely g

Nikolai Pogorelov, Takuya Matsuda

We present a review of the application of numerical methods to solve the problem of the stellar/solar wind with the local interstellar medium. Most of approaches described are developed by the authors. They include both purely gas dynamic and magnetohydrodynamic methods. Some attention is given to the influence of the neutral component of the interstellar me

Ron Workman

Even if a `complete set' of experimental observables were measured for the elastic scattering or photo/electroproduction of pseudoscalar mesons, ambiguities would remain in the extracted partial-wave and isospin decomposed amplitudes. As these problems are not widely understood, the present work outlines the way model-dependence enters into analyses of d

N. Kitanine, J. M. Maillet, V. Terras

Form factors for local spin operators of the XXZ Heisenberg spin-1/2 finite chain are computed. Representation theory of Drinfel'd twists for the sl2 quantum affine algebra in finite dimensional modules is used to calculate scalar products of Bethe states (leading to Gaudin formula) and to solve the quantum inverse problem for local spin operators in the

Arturo Magidin

A necessary and sufficient condition for an element of an algebra (in the sense of Universal Algebra) to be in the dominion of a subalgebra is given, in terms of transferable sets. This criterion is then used to formulate a more wieldy sufficient condition. Finally, some connections to a purely combinatorial setting are outlined.

Arturo Magidin

Let~$S$ be a finite nonabelian simple group, and let $H$ be a subgroup of $S$. In this work, the dominion (in the sense of Isbell) of $H$ in $S$ in rmVar(S)$ is determined, generalizing an example of B.H. Neumann. A necessary and sufficient condition for $H$ to be epimorphically embedded in $S$ is obtained. These results are then extended to a variety genera

Arturo Magidin

A full characterization of when a subgroup $H$ of a group $G$ in a varietal product ${\cal NQ}$ is epimorphically embedded in $G$ (in the variety ${\cal NQ}$) is given. From this, a result of S.~McKay is derived, which states that if ${\cal NQ}$ has instances of nonsurjective epimorphisms, then ${\cal N}$ also has instances of nonsurjective epimorphisms. Two

Arturo Magidin

An argument used to show that certain varieties of nilpotent groups have instances of nontrivial dominions is considered, and generalized. The same is done with the argument used to show that there are nontrivial dominions in the variety of metabelian groups, to suggest how this general technique may be used.

Christian Lomp

It is well-known that a ring R is semiperfect if and only if R as a left (or as a right) R-module is a supplemented module. Considering weak supplements instead of supplements we show that weakly supplemented modules M are semilocal (i.e., M/Rad(M) is semisimple) and that R is a semilocal ring if and only if R as a left (or as a right) R-module is weakly sup

Christian Lomp

The main aim of this paper is to show that an AB5*-module whose small submodules have Krull dimension has a radical having Krull dimension. The proof uses the notion of dual Goldie dimension.

Martin Karel, Haisheng Li

We study minimal generating subspaces of "weak PBW type" for vertex operator algebras that satisfy a certain condition on the grading, and we develop a procedure for finding such subspaces. As applications, we derive some results on generalized modules and produce a minimal generating space of weak PBW type for the vertex operator algebra $V_L$ assoc

Do Ngoc Diep

For Marsden-Weinstein reductions at the point 0 in the vector space dual to the Lie algebra, the well-known Jeffrey-Kirwan-Witten localization formula was proven and lastly modified by M. Vergne. We prove in this paper the same kind formula for the reductions at regular coadjoint orbits by using the universal orbital formula of characters.

Jintai Ding, Sergei Khoroshkin

We study the possibility to establish $L$-operator's formalism by Faddeev-Reshetikhin-Takhtajan-Semenov-Tian-Shansky (FRST) for quantized current algebras, that is, for quantum affine algebras in the ''new realization '' by V. Drinfeld with the corresponding Hopf algebra structure and for their Yangian counterpart. We establish this forma

M. Shifman

Supersymmetric domain walls are reviewed. The main emphasis is made on saturated walls in strongly coupled gauge theories. The central charge of the N=1 superalgebra appears in supersymmetric gluodynamics as a quantum anomaly. I also consider some rather unusual general features of supersymmetric domain walls.

Edgardo T. Garcia Alvarez, Fabian H. Gaioli

A new synthesis of the principles of relativity and quantum mechanics is developed by replacing the Poincaré group for the de Sitter one. The new relativistic quantum mechanics is an indefinite mass theory which is reduced to the standard theory on the mass shell. The charge conjugation acquires a geometrical meaning and the Stueckelberg interpretation for a

Paul Mansfield, Marcos Sampaio

For slowly varying fields the Yang-Mills Schroedinger functional can be expanded in terms of local functionals. We show how analyticity in a complex scale parameter enables the Schroedinger functional for arbitrarily varying fields to be reconstructed from this expansion. We also construct the form of the Schroedinger equation that determines the coefficient

F. C. Santos, A. Tenório, A. C. Tort

We compute the Casimir energy between an unusual pair of parallel plates at finite temperature, namely, a perfectely conducting plate ($ε\to\infty$) and an infinitely permeable one ($μ\to\infty$) by applying the generalized zeta function method. We also compute the Casimir pressure and discuss the high and the low temperature limits.

A. T. Suzuki, A. G. M. Schmidt, R. Bentín

Negative dimensional integration method (NDIM) seems to be a very promising technique for evaluating massless and/or massive Feynman diagrams. It is unique in the sense that the method gives solutions in different regions of external momenta simultaneously. Moreover, it is a technique whereby the difficulties associated with performing parametric integrals i

V. I. Shevchenko, Yu. A. Simonov

This paper is an extended version of hep-th/9802134. Dual QCD Lagrangian is derived by making use of the generalized coordinate gauge, where 1-form (vector potential) is expressed as an integral of the 2-form (field strength) along an (arbitrary) contour. As another application a simple proof of the nonabelian Stokes theorem is given.

Hugo Garcia-Compean

The space of solutions to the Hitchin equations on the dual torus with punctures determines the Higgs branch of certain impurity theories. An alternative description of this Higgs branch is provided, in terms of the proper deformation of Hitchin system with deformation parameter given by a $B$-field. For the dual torus minus the singular points we construct

B. Borasoy

The $σ$-terms are calculated at next-to-leading order in heavy baryon chiral perturbation theory by employing a cutoff regularization. The results do not depend on the cutoff value to the order we are working . The baryon masses and $σ_{πN}(0)$ are used to perform a least-squares fit to the three appearing low-energy constants and predictions for the two $KN

Michael S. Chanowitz

Two of the nine measurements of $sin^{2}θ^{lepton}_{eff}$, the effective weak interaction mixing angle, are found to be in significant conflict with the direct search limits for the Standard Model (SM) Higgs boson. Using a scale factor method, analogous to one used by the Particle Data Group, we assess the possible effect of these discrepancies on the SM fit

John Ellis, N. E. Mavromatos

We propose an identification of the conformal field theory underlying Lipatov's spin-chain model of high-energy scattering in perturbative QCD. It is a twisted N=2 supersymmetric topological field theory, which arises as the limiting case of the SL(2,R)/U(1) non-linear sigma model that also plays a role in describing the Quantum Hall effect and black hol

C. Pajares, C. A. Salgado, E. G. Ferreiro

It is shown that the multiplicity distribution associated to self-shadowing events satisfies an universal equation in terms of the minimum bias distribution. The number of elementary collisions, basic in the structure of any multiple scattering, is reduced if a collective effect like percolation of strings takes place. The main consequences of the percolatio

Michael Rueter

In the framework of the Model of the Stochastic Vacuum elastic hadron-hadron scattering, photo- and electroproduction of vectormesons and also F_2(Q^2) can be well described at center of mass energy approximately 20 GeV. The scattering amplitude is derived by smearing the color dipole-dipole scattering, which is calculated nonperturbatively in the Model of t

Michael Gronau, Jonathan L. Rosner Comments 8 pages, 1 figure, Latex

The implications of a negligible annihilation contribution in $B \to D K$ decays are reanalyzed and are shown to lead to no new constraints on the weak phase $γ$ from color-allowed $B^{\pm} \to D K^{\pm}$ decays. A test of negligible annihilation is proposed in $B^+ \to D^+ K^0$ (or $B^+ \to D^+ K^{*0}$), and an application is presented in which $γ$ can be d

Ansgar Denner, Stefano Pozzorini

The cross section for $e^-e^- \to e^-e^-$ with arbitrary electron polarizations is calculated within the Electroweak Standard Model for energies large compared to the electron mass, including the complete virtual and soft-photonic $O(α)$ radiative corrections. The relevant analytical results are listed, and a numerical evaluation is presented for the unpolar

Farida Tahir, M. Sadiq, M. Anwar Mughal, K. Ahmed

We consider tree-level corrections to hypercharge changing semileptonic decays of certain baryons induced by a minimal supersymmetric standard model with explicitly broken R-parity via $L$-violation. This study leads to a new set of constraints on the products of couplings arising from the LQd$^c$ operator of the superpotential.

S. S. Agaev

The pion and kaon electromagnetic form factors $F_{M}(Q^2)$ are calculated at the leading order of pQCD using the running coupling constant method. In computations dependence of the meson distribution amplitudes on the hard scale $Q^2$ is taken into account. The Borel transform and resummed expression for $F_{M}(Q^2)$ are found. The effect of the next-to-lea

B. Bajc, S. Fajfer, R. J. Oakes, T. N. Pham

We analyze the partial rate asymmetry in $B^{\pm} \to P {\bar P} π^{\pm}$ decays ($ P = π^+, K ^+, π^0, η$) which results from the interference of the nonresonant decay amplitude and the resonant amplitude for $B^{\pm} \to χ_{c0} π^{\pm} $ followed by the decay $χ_{c0} \to P {\bar P} $. The CP violating phase $γ$ can be extracted from the measured asymmetry.

I. M. Dremin, V. I. Man'ko

Confinement of a chromodynamical string can result in specific effects in scattering processes and multiparticle production. In particular, due to its rotation secondary fragments of the splitting apart string can move like stones thrown from a sling. That would be detected as the azimuthal asymmetry of particle distributions in individual events. Thus we pr

Ian Balitsky

I demonstrate that the amplitude of the high-energy scattering can be factorized in a product of two independent functional integrals over "fast" and "slow" fields which interact by means of Wilson-line operators -- gauge factors ordered along the straight lines.

The WA102 Collaboration, D. Barberis et al

A study of the reactions pp -> pfps(K+K-pi+pi-) and pp -> pfps(K+K-pi+pi-pi0) shows evidence for the K*K* and phi omega channels respectively. The K*K* mass spectrum shows a broad distribution with a maximum near threshold and an angular analysis shows that it is compatible with having JP = 2+. The behaviour of the cross-section as a function of centre of ma

Michael Bradley, Gyula Fodor, László Á. Gergely, Mattias Marklund

Locally rotationally symmetric perfect fluid solutions of Einstein's gravitational equations are matched along the hypersurface of vanishing pressure with the NUT metric. These rigidly rotating fluids are interpreted as sources for the vacuum exterior which consists only of a stationary region of the Taub-NUT space-time. The solution of the matching cond

Jiro Soda, Masa-aki Sakagami, Shinsuke Kawai

As a most promising candidate for quantum theory of the gravity, the superstring theory has attracted many researchers including cosmologists. It is expected that the cosmological initial singularity is avoided within the context of the superstring theory. Indeed, Antoniadis et. al. found an interesting example of the non-singular cosmological solutions by c

Eldon Emberly, George Kirczenow

We present a theoretical study of electron transport through a molecule connected to two metallic nanocontacts. The system investigated is 1,4 benzene-dithiolate (BDT) chemically bonded to two Au contacts. The surface chemistry is modeled by representing the tips of the Au contacts as two atomic clusters and treating the molecule-cluster complex as a single

Andreas Jaster

We report Monte Carlo results for the two-dimensional hard disk system. Simulations were performed in the NVT ensemble with up to 65536 disks, using a new updating scheme. We analyze the bond orientational order parameter and correlation length in the isotropic phase and the scaling behaviour of the bond orientational order parameter in the transition region

F. Maca, M. Kotrla, O. S. Trushin

We performed molecular statics calculations of energy barriers for adatom moves in the vicinity of steps on Pt(111) surface. We used the semi-empirical many-body Rosato--Guillope--Legrand potential and we systematically calculated barriers for descent of straight steps, steps with a kink and small islands as well as barriers for diffusion along the step edge

Alok Shukla, Michael Dolg, Hermann Stoll

In the present letter, we report the extension of our Wannier-function-based ab initio Hartree-Fock approach---meant originally for three-dimensional crystalline insulators---to deal with quasi-one-dimensional periodic systems such as polymers. The system studied is all-transoid polyethylene, and results on optimized lattice parameters, cohesive energy and t

Reinhard Baltin, Yuval Gefen, Gregor Hackenbroich, Hans A. Weidenmueller

We investigate the Coulomb blockade resonances and the phase of the transmission amplitude of a deformed ballistic quantum dot weakly coupled to leads. We show that preferred single--particle levels exist which stay close to the Fermi energy for a wide range of values of the gate voltage. These states give rise to sequences of Coulomb blockade resonances wit

D. Reguera, J. M. Rubi, A. Perez-Madrid

We introduce a new scheme to analyze the kinetics of homogeneous nucleation in terms of a global order parameter. Our approach is based on the application of the internal degrees of freedom formalism to derive a kinetic equation of the Kramers type formulated for a global reaction coordinate. We provide explicit expressions for the quantities and coefficient

J. M. Rubi, A. Perez-Madrid

We discuss inertial effects in systems outside equilibrium within the framework of non-equilibrium thermodynamics. By introducing a Gibbs equation in which the entropy depends on the probability density, we are able to describe a system of Brownian particles immersed in a heat bath in both inertial and diffusion regimes. In the former, a relaxation equation

W. Krauss, H. Gleiter

Nanostructured materials consist of crystalline and grain boundary components. In the simplest case, both components are chemically identical. Here, we present the results of a study of a system consisting of a crystalline component built by A atoms (tungsten) and a grain boundary component of B atoms (gallium). Within this system, component B is in a disord

J. Bricmont, K. Gawedzki, A. Kupiainen

We give a new proof of the KAM theorem for analytic Hamiltonians. The proof is inspired by a quantum field theory formulation of the problem and is based on a renormalization group argument treating the small denominators inductively scale by scale. The crucial cancellations of resonances are shown to follow from the Ward identities expressing the translatio

Claude Carignan, Sylvie Beaulieu, Stephanie Cote, Serge Demers

Neutral hydrogen (HI) has been detected in the Local Group dwarf spheroidal galaxy Sculptor with the 64 m Parkes single dish and mapped with the Australia Telescope synthesis array. Most of the detected HI is in two clouds \sim 15'-20' away from the optical center. The gas is observed at the same systemic velocity than the stars but at \ge 125 \kms a

S. K. Antiochos, C. R. DeVore, J. A. Klimchuk

We propose a new model for the initiation of a solar coronal mass ejection (CME). The model agrees with two properties of CMEs and eruptive flares that have proved to be very difficult to explain with previous models. a) Very low-lying magnetic field lines, down to the photospheric neutral line, can open toward infinity during an eruption. b) The eruption is

Kevin J. Hurley, Brian McBreen, Fergus Quilligan, Matt Delaney

A wavelet analysis has been performed on 80 intense gamma-ray bursts GRBs) from the BATSE 3B catalog with durations longer than 2 seconds. The wavelet analysis applied novel features developed for edge detection in image processing and this filtering process was used to extract a fit to the irregular GRB profile from the background. A straightforward algorit

Brian McBreen, Kevin J. Hurley

Monte Carlo simulations of long SGR event sequences based on lognormal distributions with a range of time intervals and intensity distribution parameters have been investigated. The main conclusions are that the majority of SGRs with properties similar to SGR 1806-20 have been detected but SGRs with mean waiting times much longer than SGR 1806-20 remain to b

L. Pulone, M. Salaris, A. Weiss, R. Buonanno

Theoretical relative ages of galactic globular clusters have recently been challenged by a semi-empirical relation. It was used to point out that tested sets of isochrones were unable to reproduce the relation and yield internally inconsistent relative ages. We find that differential cluster ages derived with the isochrones by Salaris & Weiss (1998) are reli

Jose A. Pons, Jose A. Font, Jose M. Ibanez, Jose M. Marti

We present a general and practical procedure to solve the general relativistic hydrodynamic equations by using any of the special relativistic Riemann solvers recently developed for describing the evolution of special relativistic flows. Our proposal relies on a local change of coordinates in terms of which the spacetime metric is locally Minkowskian and per

Ennio Poretti, Marco Scardia

We describe the problems met using the telescopes of Merate Observatory, the branch of Brera Astronomical Observatory. From the point of view of the data analysis, we discuss how to introduce a satisfactory correction of the variable extinction coefficient, giving also some examples. We also measured the sky brightness, obtaining $V$=18.2 mag/arcsec$^2$. The

Simon Hands, Susan E. Morrison

We present results of a Monte Carlo simulation of a three dimensional Gross-Neveu model with SU(2)xSU(2) chiral symmetry at non-zero baryon chemical potential mu, corresponding to non-zero baryon density. For mu sufficiently large there is a sharp transition between a phase where the chiral symmetry is broken by a condensate <qbar q> and one where the global

A. M. Ghez, B. L. Klein, M. Morris, E. E. Becklin

Over a two year period (1995-1997), we have conducted a diffraction-limited imaging study at 2.2 microns of the inner 6&#34;x6&#34; of the Galaxy&#39;s central stellar cluster using the Keck 10-m telescope. The K band images obtained reveal a large population of faint stars. We use an unbiased approach for identifying and selecting stars to be included in th

J. M. F. Labastida, Esther Perez

We analyse the perturbative series expansion of the vacuum expectation value of a Wilson loop in Chern-Simons gauge theory in the temporal gauge. From the analysis emerges the notion of the kernel of a Vassiliev invariant. The kernel of a Vassiliev invariant of order n is not a knot invariant, since it depends on the regular knot projection chosen, but it di

David Bowser-Chao, Tom D. Imbo, B. Alex King, Eric C. Martell

Observation of a sequence of resonances at an e-e- collider would suggest bound states of strongly coupled constituents carrying lepton number. Obvious candidates for these exotic constituents are leptoquarks and leptogluons. We show that under reasonable assumptions, the existence of one leptogluon flavor of appropriate mass can give rise to sizeable ``lept

M. C. Banuls, J. Bernabeu

A symmetry transformation is well defined in the case of an invariant theory, being the corresponding operator undetermined otherwise. However, we show that, even with CP violation, it is possible to determine the CP transformation by separating the Lagrangian of the Standard Model in a CP-conserving and a CP-violating part, in a unique way, making use of th

Greg Martin

A traditional &#34;Farmer Ted&#34; calculus problem is to minimize the perimeter of a rectangular chicken coop given the area N, so that as little as possible will be spent on the fencing. But what if N is an integer, and we are only allowed to consider rectangles with integer side lengths? Often it will be more cost-effective to build a coop with area small

C. Hagmann, S. Chang, P. Sikivie

We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion density. The relative importance of this source relative to misalignment production of axions depends on the spectrum. Radiation spectra for various string loop configurations are presented. T

R. J. Weymann, D. Stern, A. Bunker, H. Spinrad

We present Keck LRIS spectroscopy along with NICMOS F110W (~J) and F160W (~H) images of the galaxy HDF4-473.0 (hereafter 4-473) in the Hubble Deep Field, with a detection of an emission line consistent with Ly-alpha at a redshift of z=5.60. Attention to this object as a high redshift galaxy was first drawn by Lanzetta, Yahil and Fernandez-Soto and appeared i

Vigdor L. Teplitz, S. Alan Stern, John D. Anderson, Doris Rosenbaum

We compute the temperature and IR signal of particles of radius $a$ and albedo $α$ at heliocentric distance $R$, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of COBE DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance

C. De Conti, A. P. Galeao, F. Krmpotic

We perform a self-consistent relativistic RPA calculation for the isobaric analogue and Gamow-Teller resonances based on relativistic mean field theory results for the ground states of $^{48}$Ca, $^{90}$Zr and $^{208}$Pb. We use the parameter set NL1 for the $σ$, $ω$ and $ρ$ mesons, and experimental values for the pion and nucleon. An extra parameter, relate

W. Hollik, C. Schappacher

Radiative one-loop corrections to fermion pair production in $e^+e^-$ annihilation are calculated in the Minimal Supersymmetric Standard Model (MSSM). The size of the non-standard corrections is discussed for the process e^+e^- to mu^+mu^- and e^+e^- to hadrons at LEP2 energies and for e^+e^- to t tbar at a high energy e^+e^- collider. The relative differenc

P. Furlan, A. Ch. Ganchev, V. B. Petkova

We construct a commutative ring with identity which extends the ring of characters of finite dimensional representations of sl(3). It is generated by characters with values in the group ring $Z[\tilde{W}]$ of the extended affine Weyl group of $\hat{sl}(3)_k$ at $k\not \in Q$. The `quantised&#39; version at rational level $k+3=3/p$ realises the fusion rules o

E. Torrente-Lujan

We consider the effect of a strongly chaotic magnetic field at the narrow bottom of the convective zone of the Sun together with resonant matter oscillations on the production of electron Majorana antineutrinos. Even for moderate levels of noise, we show that it is possible to obtain a small but significant probability for $ν_e\to \barν_e$ conversions (1-3%)

Charles B. Thorn

We recall the special features of quantum dynamics on a light-front (in an infinite momentum frame) in string and field theory. The reason this approach is more effective for string than for fields is stressed: the light-front dynamics for string is that of a true Newtonian many particle system, since a string bit has a fixed Newtonian mass. In contrast, eac

F. Toschi, G. Amati, S. Succi, R. Benzi

We present a study of intermittency in a turbulent channel flow. Scaling exponents of longitudinal streamwise structure functions, $ζ_p /ζ_3$, are used as quantitative indicators of intermittency. We find that, near the center of the channel the values of $ζ_p /ζ_3$ up to $p=7$ are consistent with the assumption of homogeneous/isotropic turbulence. Moving to

S. Heinemeyer, W. Hollik, G. Weiglein

The leading diagrammatic two-loop corrections are incorporated into the prediction for the mass of the lightest Higgs boson, $\mh$, in the Minimal Supersymmetric Standard Model (MSSM). The results, containing the complete diagrammatic one-loop corrections, the new two-loop result and refinement terms incorporating leading electroweak two-loop and higher-orde

Tao Han, Ren-Jie Zhang

We study the observability for a Standard Model-like Higgs boson at an upgraded Tevatron via the modes $p \bar p \to gg \to h \to \ww \to \ljj$ and $\ll$. We find that with c. m. energy of 2 TeV and an integrated luminosity of 30 fb$^{-1}$ the signal may be observable for the mass range of $135 {\gev} \lsim \mh \lsim 180$ GeV at a $3-5σ$ statistical level. W

H. J. Boonstra, K. Skenderis, P. K. Townsend

We extend the correspondence between adS-supergravities and superconformal field theories on the adS boundary to a correspondence between gauged supergravities (typically with non-compact gauge groups) and quantum field theories on domain walls.

Thorsten Droese, Cristiane Morais-Smith

The thermal decay of linear chains from a metastable state is investigated. A crossover from rigid to elastic decay occurs when the number of particles, the single particle energy barrier or the coupling strength between the particles is varied. In the rigid regime, the single particle energy barrier is small compared to the coupling strength and the decay o

P. G. J. van Dongen, G. S. Uhrig, E. Mueller-Hartmann

In this paper we comment on the &#34;Local Fermi Liquid Theory&#34;, proposed by Engelbrecht and Bedell [1]. We emphasize several important properties of the limit of infinite dimensions, in particular the k-dependence of the irreducible vertex function, the anisotropy of the Fermi surface and the necessary conditions for phase separation. It appears that th

A. A. Penin, A. A. Pivovarov

We present a consistent analysis of $Υ$ sum rules and $B$-meson semileptonic width in the next-to-next-to-leading order in the strong coupling constant. The analysis is based on the analytical result for the heavy quark vector current correlator near threshold in the second order in perturbative and relativistic expansion around the nonrelativistic Coulomb a

Abhas Mitra

We emphasize a that since GRB970508 released an energy of Q_g~10^{51} Ωergs in soft gamma rays alone, the actual energy of the e^+e^- p FB driving the blast wave could be considerably higher than this value, Q_{FB} >Q_g. For reasonably large values of Ω, as is probably suggested by the radio observations, the value of Q_{FB} ~ 5.10^{51}~t_m^3~n_1 erg, for GR

Ron Rubin, Andrew Lesniewski

We present here a canonical description for quantizing classical maps on a torus. We prove theorems analagous to classical theorems on mixing and ergodicity in terms of a quantum Koopman space $ L^2 (A_\hbar},τ_\hbar) $ obtained as the completion of the algebra of observables $ A_\hbar $ in the norm induced by the following inner product $(A,B) =τ_{\hbar}(A^

N. David Mermin

In honor of Daniel Greenberger&#39;s 65th birthday I record for posterity two superb examples of his wit, offer a proof of an important theorem on quantum correlations that even those of us over 60 can understand, and suggest, by trying to make it look silly, that invoking ``quantum nonlocality&#39;&#39; as an explanation for such correlations may be too che

A. V. Fedotov, R. L. Gluckstern, S. S. Kurennoy, R. D. Ryne

A new class of self-consistent 6-D phase space stationary distributions is constructed both analytically and numerically. The beam is then mismatched longitudinally and/or transversely, and we explore the beam stability and halo formation for the case of 3-D axisymmetric beam bunches using particle-in-cell simulations. We concentrate on beams with bunch leng

Sergey S. Kurennoy

Cavity loss factors can be easily computed for ultrarelativistic beams using time-domain codes like MAFIA or ABCI. However, for non-ultrarelativistic beams the problem is more complicated because of difficulties with its numerical formulation in the time domain. We calculate the loss factors of a non-ultrarelativistic bunch and compare results with the relat

Sergey S. Kurennoy

The 1.7-GeV 100-mA CW proton linac is now under design for the Accelerator Production of Tritium (APT) Project. The APT linac comprises both the normal conducting (below 211 MeV) and superconducting (SC) sections. The high current leads to stringent restrictions on allowable beam losses (<1 nA/m), that requires analyzing carefully all possible loss sources.

G. M. Bruun, K. Burnett

In view of ongoing experiments to trap ultracold spin-polarized $^6$Li, we study various properties of an interacting Fermi gas in a harmonic trap taking the discrete nature of the unperturbed harmonic trap levels into account exactly. As $^6$Li has a rather large and negative scattering length, we focus on the effects of the attractive atom-atom interaction

S. Ulrych, H. Müther

The unpolarized response functions of the quasielastic $^{16}O(e,e^\prime p)^{15}N$ reaction are calculated for three different types of relativistic bound state wave functions. The wave functions are obtained from relativistic Hartree, relativistic Hartree-Fock and density dependent relativistic Hartree calculations that reproduce the experimental charge ra

Thomas R. Hemmert

I discuss recent work on nucleon form factors, magnetic strangeness in the nucleon and the isovector nucleon-delta transition based on the broken chiral symmetry of QCD, utilizing recent theoretical developments in ChPT.

J. C. Hardy, I. S. Towner

Superallowed $0^+ \to 0^+$ nuclear beta decay provides a direct measure of the weak vector coupling constant, $\GV$. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of $^{10}$C to that of $^{54}$Co, and demonstrate that the results confirm conservation of the weak vector current (CVC) but di

J. Van der Jeugt, R. Jagannathan

Positive discrete series representations of the Lie algebra $su(1,1)$ and the quantum algebra $U_q(su(1,1))$ are considered. The diagonalization of a self-adjoint operator (the Hamiltonian) in these representations and in tensor products of such representations is determined, and the generalized eigenvectors are constructed in terms of orthogonal polynomials

Igor Belegradek

We obtain some restrictions on the topology of infinite volume hyperbolic manifolds. In particular, for any n and any closed negatively curved manifold M of dimension greater than 2, only finitely many hyperbolic n-manifolds are total spaces of orientable vector bundles over M.

S. J. Dilworth, Ralph Howard, James W. Roberts

A real valued function $f$ defined on a convex $K$ is anemconvex function iff it satisfies $$ f((x+y)/2) \le (f(x)+f(y))/2 + 1. $$ A thorough study of approximately convex functions is made. The principal results are a sharp universal upper bound for lower semi-continuous approximately convex functions that vanish on the vertices of a simplex and an explicit

Greg Martin

We investigate, using the weighted linear sieve, the distribution of almost-primes among the residue classes (mod p) that generate the multiplicative group of reduced residue classes. We are concerned with finding an upper bound for the least prime or almost-prime primitive root (mod p) that holds uniformly for all p, analogous to Linnik&#39;s Theorem on a u

Greg Martin

We derive, for all prime moduli p except those in a very thin set, an upper bound for the least prime primitive root (mod p) of order of magnitude a constant power of log p. The improvement over previous results, where the upper bound was log p to an exponent tending to infinity with p, lies in the use of the linear sieve (a particular version called the shi

Martin A. Guest, Michal Kwiecinski, Boon-Wee Ong

We prove a topological result concerning the kernel of a morphism d : E --> F of holomorphic vector bundles over a complex analytic space. As a consequence, we show that the projectivization P(ker d) is a quasifibration up to some dimension. We give an application to the Abel-Jacobi map of a Riemann surface, and to the space of rational curves in the symmetr

Do Ngoc Diep, Aderemi O. Kuku, Nguyen Quoc Tho

In this paper we compute the K-theory (algebraic and topological) and entire periodic cyclic homology of compact Lie group C*-algebras, define Chern characters between them and show that the Chern characters in both topological and algebraic cases are isomorphisms.

B. Abdesselam, A. Chakrabarti, R. Chakrabarti, J. Segar

A general construction is given for a class of invertible maps between the classical $U(sl(2))$ and the Jordanian $U_{h}(sl(2))$ algebras. Different maps are directly useful in different contexts. Similarity trasformations connecting them, in so far as they can be explicitly constructed, enable us to translate results obtained in terms of one to the other ca

Jorgen Rasmussen

In this paper we develop a general method for constructing 3-point functions in conformal field theory with affine Lie group symmetry, continuing our recent work on 2-point functions. The results are provided in terms of triangular coordinates used in a wave function description of vectors in highest weight modules. In this framework, complicated couplings t

Ashok Das, Carlos Farina

We show how Schwinger&#39;s proper time method can be used to evaluate directly the determinant of first order operators associated with fermionic theories. Several examples are worked out in detail.

Raphael Bousso, Stephen Hawking

The wave function of the universe is usually taken to be a functional of the three-metric on a spacelike section, Sigma, which is measured. It is sometimes better, however, to work in the conjugate representation, where the wave function depends on a quantity related to the second fundamental form of Sigma. This makes it possible to ensure that Sigma is part

J. A. Nieto, J. Socorro

In this work we propose an action which unifies self-dual gravity and self-dual Yang-Mills in the context of the Macdowell-Mansouri formalism. We claim that such an action may be used to find the S-dual action for both self-dual gravity and self-dual Yang-Mills.

Michael Perkins, Peter Bowcock

The $O(β^2)$ quantum correction to the classical reflection factor is calculated for one of the integrable boundary conditions of $a_2^{(1)}$ affine Toda field theory. This is found to agree with the conjectured exact reflection factor of the quantum theory. We consider the existence of other exact reflection factors consistent with our perturbative answer a

Herbert Nachbagauer

We discuss differential-- versus integral--equation based methods describing out--of thermal equilibrium systems and emphasize the importance of a well defined reduction to statistical observables. Applying the projection operator approach, we investigate on the time evolution of expectation values of linear and quadratic polynomials in position and momentum