March 1996 arXiv papers — page 5

Edward Shuryak

In a style of popular article, we discuss models of hadronic structure and their relation with models of the QCD vacuum and lattice simulations. Borrowing two main characters from G.Gamow, Mr.Thompson and Professor, we make a travel in the QCD vacuum. Instanton-generated interaction between quarks appear to be major player, they create quark condensate, cons

E. Garrido, D. V. Fedorov, A. S. Jensen

Momentum distributions of particles from nuclear break-up of fast three-body halos are calculated consistently, and applied to $^{11}$Li. The same two-body interactions between the three particles are used to calculate the ground state structure and the final state of the reaction processes. We reproduce the available momentum distributions from $^{11}$Li fr

G. Kaniadakis, A. Lavagno, P. Quarati

The empirical-phenomenological quasi-deuteron photofission description is theoretically justified within the semiclassical, intermediate statistics model. The transmutational fermion (nucleon) - boson (quasi-deuteron) potential plays an essential role in the present context and is expressed in terms of thermodynamical and of microscopical quantities, analogo

J. I. Johansson, H. S. Sherif, G. M. Lotz

Relativistic calculations for the quasifree electron scattering process (e, e'p) and the direct knockout contribution to (gamma, p) reactions are presented. The spectroscopic factors determined from the former reaction are used to fix the magnitude of the knockout contribution to the (gamma, p) reaction at 60 MeV. The results obtained for several nuclei

Alexander Koldobsky

For $0<q\le 2,\ 1\le k < n,$ let $X=(X_1,...,X_n)$ and $Y=(Y_1,...,Y_n)$ be symmetric $q$-stable random vectors so that the joint distributions of $X_1,...,X_k$ and $X_{k+1},...,X_n$ are equal to the joint distributions of $Y_1,...,Y_k$ and $Y_{k+1},...,Y_n,$ respectively, but $Y_i$ and $Y_j$ are independent for every $1\le i \le k,\ k+1\le j \le n.$ We prov

A. Gorsky, A. Marshakov, A. Mironov, A. Morozov

The form of the spectral curve for $4d$ $N=2$ supersymmetric Yang-Mills theory with matter fields in the fundamental representation of the gauge group suggests that its $1d$ integrable counterpart should be looked for among (inhomogeneous) $sl(2)$ spin chains with the length of the chain being equal to the number of colours $N_c$. For $N_f < 2N_c$ the releva

Federico Finkel, Artemio Gonzalez-Lopez, Niky Kamran, Peter J. Olver

This paper surveys recent work on Lie algebras of differential operators and their application to the construction of quasi-exactly solvable Schroedinger operators.

G. Amelino-Camelia

The issues that arise when using the Cornwall-Jackiw-Tomboulis formalism in multi-field theories are investigated. Particular attention is devoted to the interplay between temperature effects, ultraviolet structure, and the interdependence of the gap equations. Results are presented explicitly in the case of the evaluation of the finite temperature effective

A. Djouadi, P. Janot, J. Kalinowski, P. M. Zerwas

Among the possible decay modes of Higgs particles into supersymmetric states, neutralino and chargino decays play a prominent rôle. The experimental opportunities of observing such decay modes at LEP2 and at future e+e- linear colliders are analyzed within the frame of the Minimal Supersymmetric extension of the Standard Model. For heavy Higgs particles, the

W. Vogelsang

We present a complete description of the calculation of the spin-dependent next-to-leading order splitting functions. The calculation is performed in the light-cone gauge. We give results for different prescriptions for the Dirac matrix $γ_5$ in $d=4-2 ε$ dimensions and provide the link to the results in dimensional reduction.

M. Gogberashvili, L. Midodashvili, P. Midodashvili

It is evaluated the first order temperature correction to the energy of massive neutrino in the case of weak magnetic field.

C. Boros, Liang Zuo-tang, Meng Ta-chung, R. Rittel

It is pointed out that the existing models for the left-right asymmetries observed in single-spin inclusive hadron production processes can be differentiated experimentally. Several such experiments are proposed with which the basic assumptions of these models can be tested individually.

Debajyoti Choudhury, Probir Roy

Strong upper bounds are derived on certain product combinations of lepton nonconserving couplings in the minimal supersymmetric standard model with explicit $R$-parity violation. The input is information from rare leptonic decays of the long-lived neutral kaon, the muon and the tau as well as from the mixings of neutral $K$- and $B$-mesons. One of these boun

E. N. Argyres, A. B. Lahanas, C. G. Papadopoulos, V. C. Spanos

We study the C and P even WWγand WWZ trilinear gauge boson vertices (TGV&#39;s), in the context of the MSSM assuming that the external W&#39;s are on their mass shell. We find that for energies less than 200 GeV squark and slepton contributions to the aforementioned couplings are two orders of magnitude smaller than those of the Standard Model (SM). In the s

J. Kwiecinski, S. C. Lang, A. D. Martin

We calculate the rate of producing deep inelastic events containing an energetic isolated forward photon at HERA. We quantify the enhancement arising from the leading $\log 1/x$ gluon emissions with a view to using such events to identify the underlying dynamics.

A. Barducci, R. Casalbuoni, M. Modugno, G. Pettini

We present a derivation of the bosonic contribution to the thermodynamical potential of four fermion models by means of a $1/N_c$-expansion of the functional integral defining the partition function. This expansion turns out to be particularly useful to correct the mean field approximation expecially at low temperatures, where the relevant degrees of freedom

A. Bramon, P. Gosdzinsky, S. Tortosa

The $η\to π^+ π^- π^0 γ$ decay is discussed in the general context of Chiral Perturbation Theory (ChPT), assuming that the low--energy constants (counter--terms) are saturated by vector-meson resonances. The $η\to π^+ π^- π^0 γ$ amplitude can be separated in two distinct pieces: the inner bremsstrahlung, $A^{(IB)}$, and the structure dependent (or direct emi

M. Yoshimura

In recent studies it has become increasingly clear that presence of infinitely many instability bands of the parametric resonance plays crucial roles in the phenomenon of particle production under periodic classical field oscillation. We extend previous works to a general class of models including both the Yukawa and the quartic type of couplings of the clas

Thomas DeGrand, Anna Hasenfratz, Decai Zhu

We describe the properties of instantons in lattice gauge theory when the action is a fixed point action of some renormalization group transformation. We present a theoretically consistent method for measuring topological charge using an inverse renormalization group transformation. We show that, using a fixed point action, the action of smooth configuration

Jose A. Zapata

Topological gravity is the reduction of general relativity to flat space-times. A lattice model describing topological gravity is developed starting from a Hamiltonian lattice version of $B\w F$ theory. The extra symmetries not present in gravity that kill the local degrees of freedom in $B\wedge F$ theory are removed. The remaining symmetries preserve the g

G. Di Cecio, A. Di Giacomo, G. Paffuti, M. Trigiante

A disorder parameter is constructed which signals the condensation of vortices. The construction is tested by numerical simulations.

Vl. V. Papoyan, R. R. Shcherbakov

An Abelian sandpile model is considered on the Husimi lattice of square plaquettes. Exact expressions for the distribution of height probabilities in the Self-Organized Critical state are derived. The two-point correlation function for the sites deep inside the Husimi lattice is calculated exactly.

Vl. V. Papoyan, R. R. Shcherbakov

An Abelian sandpile model is considered on the Husimi lattice of triangles with an arbitrary coordination number q. Exact expressions for the distribution of height probabilities in the Self-Organized Critical state are derived.

V. Gasparian, T. Christen, M. Buttiker

The response of an arbitrary scattering problem to quasi-static perturbations in the scattering potential is naturally expressed in terms of a set of local partial densities of states and a set of sensitivities each associated with one element of the scattering matrix. We define the local partial densities of states and the sensitivities in terms of function

V. I. Belitsky, A. Cantarero, S. T. Pavlov

A strongly asymmetric, Fano-like resonance profile has been found for magneto-absorption in the states of hot free electron-hole pairs scattered by defects in bulk semiconductors. The renormalization of the absorption profile, compared to that expected from the bare density of states in a high magnetic field, follows from a quasi-one-dimensional character of

A. P. Polychronakos

The one-quasihole wavefunctions and their norms are derived for the system of particles on the line with inverse-square interactions and harmonic confining potential.

Simon P. Driver, Steven Phillipps

Recent observations of the galaxy population within rich clusters have found a characteristic luminosity distribution described by a flat (alpha = -1.0) Schechter function which exhibits an upturn at faint absolute magnitudes (B Mag = -18). Here we discuss whether such a form for the field luminosity distribution is ruled out by local and/or faint magnitude

D. J. Crary, C. Kouveliotou, J. van Paradijs, F. van der Hooft

We have analyzed approximately 1100 days of Cygnus X-1 hard X-ray data obtained with BATSE to study its rapid variability. We find for the first time correlations between the slope of the spectrum and the hard X-ray intensity, and between the spectral slope and the amplitude of the rapid variations of the hard X-ray flux. We compare our results with expectat

U. Lisenfeld, P. Alexander, G. G. Pooley, T. Wilding

We present high-sensitivity multi-frequency radio continuum observations of the starburst galaxy NGC~2146. We have fitted these data with a three-dimensional diffusion model. The model can describe the radio emission from the inner disk of NGC~2146 well, indicating that diffusion is the dominant mode of propagation in this region. Our results are indicating

A. Possenti, S. Mereghetti, M. Colpi

We present the results of a spectral and timing analysis of PSR 0656+14 based on the complete set of ROSAT observations carried out with the PSPC instrument in 1991 and 1992. The present analysis confirms the thermal origin of the bulk of the emission in the soft X-ray band (Finley et al. 1992). In addition, we find strong evidence of a harder component, des

G. Kaniadakis, A. Lavagno, P. Quarati

The generalized Tsallis statistics produces a distribution function appropriate to describe the interior solar plasma, thought as a stellar polytrope, showing a tail depleted respect to the Maxwell-Boltzmann distribution and reduces to zero at energies greater than about $20 \, k_{_B} T$. The Tsallis statistics can theoretically support the distribution sugg

D. Koester, D. S. Finley, N. F. Allard, J. W. Kruk

We present new FUV/UV observations of the DA white dwarf Wolf 1346 obtained with the Hopkins Ultraviolet Telescope. The atmospheric parameters of this object are estimated from a fit of model atmospheres to several optical spectra to be Teff = 20000 K, log g = 7.90. From the optical spectrum this star is a normal DA without any indications for chemical eleme

P. K. Sahu, A. R. Prasanna

We study the radial pulsation frequencies of slowly rotating neutron stars in general relativistic formalism using realistic equations of state. It is found that the pulsation frequencies are always an increasing function of rotation rate. The increasing rate of frequency depends on the nature of equations of state.

Chris Flynn, Jesper Sommer-Larsen, Per Rex Christensen

We have tested whether the simple model for the kinematics of the Galactic stellar halo (in particular the outer halo) proposed by Sommer-Larsen, Flynn and Christensen (SLFC) is physically realizable, by directly integrating particles in a 3-D model of the Galactic potential. We are able to show that the SLFC solution can be realized in terms of a distributi

Joseph D. Lykken

Recent developments in string duality suggest that the string scale may not be irrevocably tied to the Planck scale. Two explicit but unrealistic examples are described where the ratio of the string scale to the Planck scale is arbitrarily small. Solutions which are more realistic may exist in the intermediate coupling or ``truly strong coupling'' region of

W. de Boer, G. Burkart, R. Ehret, J. Lautenbacher

Within the Constrained Minimal Supersymmetric Standard Model it is possible to predict the low energy gauge couplings and masses of the 3. generation particles from a few parameters at the GUT scale. In addition the MSSM predicts elektroweak symmetry breaking due to large radiative corrections from Yukawa couplings, thus relating the Z^0 boson mass to the to

Robin G. Stuart

The process $e^+e^-\rightarrow \bar ν_e e^-W^+ \rightarrow\barν_e e^-u\bar d$ is considered as an example of the problems associated with maintaining gauge invariance in matrix elements involving unstable particles. It is shown how to construct a matrix element that correctly treats width effects for the intermediate unstable $W$ boson and that is both $SU(2

Maciej A. Nowak, Gábor Papp, Ismail Zahed

We use the law of addition in random matrix theory to analyze the spectral distributions of a variety of chiral random matrix models as inspired from QCD whether through symmetries or models. In terms of the Blue&#39;s functions recently discussed by Zee, we show that most of the spectral distributions in the macroscopic limit and the quenched approximation,

F. del Aguila, M. Masip, M. Perez-Victoria

This is a short review of present and future limits on new neutral gauge bosons, in particular on hadrophilic or leptophobic $Z&#39;$s recently proposed to interpret the observed fluctuations of $Γ_{c,b}$ at LEP. Light gauge bosons coupled to lepton number differences or to baryon number are also examples of the model dependence of these bounds. The mixing b

A. V. Gladyshev, D. I. Kazakov, W. de Boer, G. Burkart

Within the framework of the Minimal Supersymmetric Standard Model (MSSM) the Higgs masses and LEP II production cross sections are calculated for a wide range of the parameter space. In addition, the parameter space restricted by unification, electroweak symmetry breaking and other low energy constraints is considered in detail, in which case the masses of a

Konrad Banaszek, Krzysztof Wodkiewicz

We propose a very simple experimental setup to measure, via photon counting, the overlap of the Wigner functions characterizing two single mode light beams. We show that this scheme can be applied to determine directly the phase space quasiprobability distribution of the single mode field and in a certain limit the Wigner function can be measured without use

Ansgar Denner, Stefan Dittmaier

In contrast to the conventional treatment of gauge theories, in the background-field method the Ward identities for connected Green functions are not violated by Dyson summation of self-energies in finite orders of perturbation theory. Thus, Dyson summation does not spoil gauge cancelations at high energies which are ruled by the Goldstone-boson equivalence

D. Melikhov

Quark model results for the $B\to π,ρ$ decays are analysed, making use of the dispersion formulation of the model: The form factors at $q^2>0$ are expressed as relativistic invariant double spectral representation over invariant masses of the initial and final mesons through their light--cone wave functions. The dependence of the results on the quark model p

Hiroyuki Kawamura, Tsuneo Uematsu, Yoshiaki Yasui, Jiro Kodaira

The QCD effects of twist-4 operators on the first moment of nucleon spin-dependent structure function $g_1(x, Q^2 )$ are studied in the framework of operator product expansion and renormalization group method. We investigate the operator mixing through renormalization of the twist-4 operators including those proportional to the equation of motion by evaluati

Kazuo Fujikawa

The notion of index is applied to analyze the phase operator problem associated with the photon. We clarify the absence of the hermitian phase operator on the basis of an index consideration. We point out an interesting analogy between the phase operator problem and the chiral anomaly in gauge theory, and an appearance of a new class of quantum anomaly is no

Daniel Kabat, Philippe Pouliot

We consider low energy, non-relativistic scattering of two Dirichlet zero-branes as an exercise in quantum mechanics. For weak string coupling and sufficiently small velocity, the dynamics is governed by an effective U(2) gauge theory in 0+1 dimensions. At low energies, D-brane scattering can reliably probe distances much shorter than the string scale. The o

S. Hosono, B. H. Lian, S. -T. Yau

Motivated by mirror symmetry, we study certain integral representations of solutions to the Gel&#39;fand-Kapranov-Zelevinsky(GKZ) hypergeometric system. Some of these solutions arise as period integrals for Calabi-Yau manifolds in mirror symmetry. We prove that for a suitable compactification of the parameter space, there exists certain special boundary poin

Samuel L. Braunstein

We show how to perform error correction of single qubit dephasing by encoding a single qubit into a minimum of three. This may be performed in a manner closely analogous to classical error correction schemes. Further, the resulting quantum error correction schemes are trivially generalized to the minimal encoding of arbitrarily many qubits so as to allow for

Wenbin Zhang, Jorge Vinals

Pattern formation in parametric surface waves is studied in the limit of weak viscous dissipation. A set of quasi-potential equations (QPEs) is introduced that admits a closed representation in terms of surface variables alone. A multiscale expansion of the QPEs reveals the importance of triad resonant interactions, and the saturating effect of the driving f

G. Kaniadakis, A. Lavagno, P. Quarati

We link, by means of a semiclassical approach, the fractional statistics of particles obeying the Haldane exclusion principle to the Tsallis statistics and derive a generalized quantum entropy and its associated statistics.

Jussi Kalkkinen, Antti J. Niemi

We introduce new variables in four dimensional SU(N) Yang-Mills theory. These variables emerge when we sum the path integral over classical solutions and represent the summation as an integral over appropriate degrees of freedom. In this way we get an effective field theory with SU(N)$\times$SU(N) gauge symmetry. In the instanton approximation our effective

T. Nakatsu, K. Takasaki

The exact solutions (Seiberg-Witten type) of $N=2$ supersymmetric Yang-Mills theory are discussed from the view of Whitham-Toda hierarchy.

Kyoungtae Kimm, Kimyeong Lee, Taejin Lee

We study the Chern-Simons $CP(N)$ models with a global $U(1)$ symmetry and found the self-dual models among them. The Bogomolnyi-type bound in these self-dual models is a nontrivial generalization of that in the pure $CP(N)$ models. Our models have quite a rich vacuum and soliton structure and approach the many known gauged self-dual models in some limit.

N. Armesto, M. A. Braun

The EMC effect is studied in the perturbative QCD hard pomeron approach. In the limit $x\rightarrow 0$ and for a nucleus with a constant density the effect is found to be a function of a single variable which combines its $x$-, $Q$- and $A$-dependence. At large $Q^{2}$ the effect dies out as $\ln Q/Q$. At small but finite $x$ a change in the anomalous dimens

E. Keith, Ernest Ma

The totality of neutrino-oscillation phenomena appears to require the existence of a light singlet neutrino. As pointed out recently, this can be naturally accommodated with a specific extra U(1) factor contained in the superstring-inspired E$_6$ model and its implied particle spectrum. We analyze this model for other possible consequences. We discuss specif

K. Melnikov, G. L. Kotkin, V. G. Serbo

We present qualitative but precise description of the linear beam-size effect predicted for the processes in which unstable but long--living particles collide with each other. We derive physically pronounced equation for the events rate which proves that the linear beam-size effect corresponds to the scattering of one beam of particles on the decay products

Ehab Malkawi, Tim Tait, C. --P. Yuan

We discuss a model in which the third generation fermions undergo a different $SU(2)$ weak interaction from the first two generation fermions. In general, a flavor changing neutral current interaction is expected. Constrained by the precision low energy data, the mass ($M_{Z&#39;}=M_{W&#39;}$) of the heavy gauge bosons is bounded from below to be about $1.1$

G. D&#39;Ambrosio, G. Ecker, G. Isidori, H. Neufeld

We present a general discussion of radiative four--meson processes to $O(p^4)$ in chiral perturbation theory. We propose a definition of ``generalized bremsstrahlung&#39;&#39; that takes full advantage of experimental information on the corresponding non--radiative process. We also derive general formulae for one--loop amplitudes which can be applied, for in

Michael M. Tung

We examine the O(alpha_s) forward-backward asymmetries for the production process e+ e- --> gamma,Z --> q qbar (g), tagging the outgoing heavy-quark jet at center-of-momentum energies off the Z-peak. The complicated analytic results are reduced to simple polynomial forms that provide excellent approximations. For charm and bottom quark, a full dynamical canc

S. M. Lietti, S. F. Novaes, R. Rosenfeld

We study the effect of anomalous $Hγγ$ and $HZγ$ couplings, described by a general effective Lagrangian, on the process $e^+ e^- \to b \bar{b} γ$ at LEP2 energies. We include the relevant irreducible standard model background to this process, and from the photon energy spectrum, we determine the reach of LEP2 to unravel the anomalous couplings by analyzing t

V. Berezinsky, A. Bottino, J. Ellis, N. Fornengo

Neutrino telescopes of large area offer the possibility of searching for indirect signals of relic neutralinos in the galactic halo, due to annihilations in the Sun or the Earth. Here we investigate the sensitivity, using a supergravity scheme where the soft scalar mass terms are not constrained by universality conditions at the grand unification scale. We f

T. S. Biro, M. H. Thoma

The damping rate of a Higgs field at zero momentum is calculated using the Braaten-Pisarski method and compared to the Lyapunov exponent of the classical SU(2) Yang-Mills Higgs system.

Hideyuki Tagoshi, Masaru Shibata, Takahiro Tanaka, Misao Sasaki

Extending a method developed by Sasaki in the Schwarzschild case and by Shibata, Sasaki, Tagoshi, and Tanaka in the Kerr case, we calculate the post-Newtonian expansion of the gravitational wave luminosities from a test particle in circular orbit around a rotating black hole up to $O(v^8)$ beyond the quadrupole formula. The orbit of a test particle is restri

David Borthwick, Alan McRae, Edward Taylor

Take two isomorphic convex co-compact co-infinite volume Kleinian groups, whose regular sets are diffeomorphic. The quotient of hyperbolic 3-space by these groups gives two hyperbolic 3-manifolds whose scattering operators may be compared. We prove that the operator norm of the difference between the scattering operators is small, then the groups are related

Theodore Voronov

We investigate forms on supermanifolds defined as Lagrangians of ``copaths&#39;&#39; (that is, systems of equations, which may or may not specify submanifolds). For this, we consider direct products $M^{n|m}\times\Bbb R^{r|s}$ and study isomorphisms corresponding to simultaneously advancing the number of additional parameters $r|s$ and the number of equation

Paul Biran

We prove that the space of symplectic packings of ${\Bbb C}P^2$ by $k$ equal balls is connected for $3\leq k\leq 6$. The proof is based on Gromov-Witten invariants and on the inflation technique due to Lalonde and McDuff.

R. Combescot, X. Leyronas

We have studied the effect of impurities on $T_{c}$ for a model of YBCO involving pairing both in the CuO$_{2}$ planes and in the CuO chains. In this model pairing in the planes is due to phonons, while Coulomb repulsion induces in the chains an order parameter with opposite sign. Due to the anticrossing produced by hybridization between planes and chains, t

Normand Mousseau

I study the Chate-Manneville cellular automata rules on randomly connected lattices. The periodic and quasi-periodic macroscopic behaviours associated with these rules on finite-dimensional lattices persist on an infinite-dimensional lattice with finite connectivity and symmetric bonds. The lower critical connectivity for these models is at C=4 and the mean-

S. Bornholdt, P. Buettner, N. Tetradis, C. Wetterich

The critical behaviour of a system of two coupled scalar fields in three dimensions is studied within the formalism of the effective average action. The fixed points of the system are identified and the crossover between them is described in detail. Besides the universal critical behaviour, the flow of the coarse grained free energy also describes the approa

E. A. Jagla, C. A. Balseiro

We use a three dimensional stacked triangular network of Josephson junctions as a model for the study of vortex structure in the mixed state of high Tc superconductors. We show that the addition of disorder destroys the first order melting transition occurring for clean samples. The melting transition splits in two different (continuous) transitions, ocurrin

J. Neuefeind, K. D. Liss

The distribution of Ge-O-Ge and Si-O-Si bond angles alpha in amorphous germania and silica is re-determined on the basis of diffraction experiments. The bond angle alpha joining adjacent tetrahedra is the central parameter of any continuous random network description (CRN) of these glasses. New high energy photon diffraction experiments on amorphous germania

Richard E. Griffiths, Roberto Della Ceca, Ioannis Georgantopoulos, Brian J. Boyle

X-ray luminous narrow emision-line galaxies (NELG) have been previously identified and proposed as an important class of extragalactic X-ray sources, with a potentially significant contribution to the total extragalactic X-ray flux at energies below $\sim$ 10 keV. In order to investigate and clarify this possibility, we have used a sample of NELG found in 5

K. J. Mighell, R. M. Rich, M. Shara, S. M. Fall

We present our analysis of Hubble Space Telescope Wide Field Planetary Camera 2 observations in F555W (broadband V) and F450W (broadband B) of the globular cluster Hodge 11 in the Large Magellanic Cloud galaxy. The resulting V vs. (B-V) color-magnitude diagram reaches 2.4 mag below the main-sequence turnoff (which is at V_TO = 22.65 +- 0.10 mag or M_V^TO = 4

D. Trevese, G. Cirimele, B. Appodia

A study of the luminosity function of 36 Abell clusters of galaxies has been carried out using photographic plates obtained with the Palomar 1.2 m Schmidt telescope. The relation between the magnitude M_1 of the brightest cluster member and the Schechter function parameter M* has been analyzed. A positive correlation between M* and M_1 is found. However clus

Matthias Bartelmann, Matthias Steinmetz

We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and they are examined at redshifts between 1 and 0. We compute the X-ray emission of the intracluster gas by thermal bremsstra

Paul B. Eskridge, Raymond E. White, David S. Davis

We have analysed archival {\it ROSAT} PSPC data for M32 in order to study the x-ray emission from this nearest elliptical galaxy. We fit spectra from three long exposures with Raymond-Smith, thermal bremsstrahlung, and power-law models. All models give excellent fits. The thermal fits have kT$\approx$4 keV, the Raymond-Smith iron abundance is $0.4^{+0.7}_{-0

R. Dijkgraaf, E. Verlinde, H. Verlinde

We propose a formulation of 11-dimensional M-theory in terms of five-branes with closed strings on their world-volume. We use this description to construct the complete spectrum of BPS states in compactifications to six and five dimensions. We compute the degeneracy for fixed charge and find it to be in accordance with U-duality (which in our formulation is

D. Boyanovsky, D. Brahm, R. Holman, D. -S. Lee

We propose a gauge invariant formulation of the effective potential in terms of a gauge invariant order parameter, for the Abelian Higgs model. The one-loop contribution at zero and finite temperature is computed explicitly, and the leading terms in the high temperature expansion are obtained. The result is contrasted to the effective potential obtained in s

S. P. Strong, Roland Koberle, Rob R. de Ruyter van Steveninck, William Bialek

The nervous system represents time-dependent signals in sequences of discrete action potentials or spikes, all spikes are identical so that information is carried only in the spike arrival times. We show how to quantify this information, in bits, free from any assumptions about which features of the spike train or input waveform are most important. We apply

Pijush K. Ghosh

We consider a $CP^N$ model with the subgroup $SU(r)$ completely gauged, where $1 < r < N+1$. The gauge field dynamics is solely governed by a nonabelian Chern-Simons term and the global $SU(N+1)$ symmetry is broken explicitly by introducing a $SU(r)$ invariant scalar potential. We obtain self-dual equations of this gauged $CP^N$ model and find that the energ

Tomasz Brzezinski

We introduce the notion of a crossed product of an algebra by a coalgebra $C$, which generalises the notion of a crossed product by a bialgebra well-studied in the theory of Hopf algebras. The result of such a crossed product is an algebra which is also a right $C$-comodule. We find the necessary and sufficient conditions for two coalgebra crossed products b

Jacek Dziarmaga

Removed to be revised. Diagonalization for a larger cut-off M shows that the definite size effects are M-dependent. Scaling with M shows that in the thermodynamic limit the skyrmion wave-function tends to the translationally invariant hard core wave function. Finite M breaks translational invariance and at the same time it exponentially suppresses the tail o

S. Aid, H1 Collaboration

Results on \jpsi production in $e p$ interactionsin the H1 experiment at HERA are presented. The \jpsi mesons are produced by almost real photons ($Q^2\approx 0$) and detected via their leptonic decays. The data have been taken in 1994 and correspond to an integrated luminosity of $2.7 {pb}^{-1}$. The $γp$ cross section for elastic \jpsi production is observ

Asher Peres

Pairs of spin-1/2 particles are prepared in a Werner state (namely, a mixture of singlet and random components). If the random component is large enough, the statistical results of spin measurements that may be performed on each pair separately can be reproduced by an algorithm involving local ``hidden&#39;&#39; variables. However, if several such pairs are

S. Aid, H1 Collaboration

A new measurement of the proton structure function $F_2(x,Q^2)$ is reported for momentum transfers squared $Q^2$ between 1.5 GeV$^2$ and 5000 GeV$^2$ and for Bjorken $x$ between $3\cdot 10^{-5}$ and 0.32 using data collected by the HERA experiment H1 in 1994. The data represent an increase in statistics by a factor of ten with respect to the analysis of the

A. Delfino, M. Malheiro, D. P. Menezes

The structure of infinite nuclear matter is studied with two of the Zimanyi - Moszkowski (ZM) models in the framework of a relativistic approximation which takes into account Hartree terms and beyond and is compared with the results which come out of the relativistic Hartree - Fock approach in the linear Walecka model. The simple treatment applied to these m

Mannque Rho

I discuss in this lecture how to make a connection between effective chiral Lagrangians -- low-energy effective theory of QCD -- and Landau Fermi liquid theory extended by Migdal to nuclear matter. The practical purpose of such a connection is to provide a link between certain observables in relativistic heavy-ion processes and those in low-energy spectrosco

Steffen Wilke, Matthias Scheffler

The modification of the potential-energy surface (PES) of H_2 dissociation over Pd(100) as induced by the presence of a (2x2) S adlayer is investigated by density-functional theory and the linear augmented plane wave method. It is shown that the poisoning effect of S originates from the formation of energy barriers hindering the dissociation of H_2. The barr

Yehoram Gordon, Shlomo Reisner, Carsten Schütt

There are two positive, absolute constants $c_{1}$ and $c_{2}$ so that the volume of the difference set of the $d$-dimensional Euclidean ball and an inscribed polytope with n vertices is larger than $$ c_{2}\ d\ {n}^{-\frac{2}{d-1}}vol_d(B^d_2) $$ for $n \geq (c_{1}\ d)^{\frac{d-1}{2}}$.

Jens Kuester, Gernot Muenster

In quantum field theory with three-point and four-point couplings the Feynman diagrams of perturbation theory contain momentum independent subdiagrams, the ``tadpoles&#39;&#39; and ``snails&#39;&#39;. With the help of Dyson-Schwinger equations we show how these can be summed up completely by a suitable modification of the mass and coupling parameters. This r

Sergio Albeverio, Shao-Ming Fei

The relations between integrable Poisson algebras with three generators and two-dimensional manifolds are investigated. Poisson algebraic maps are also discussed.

Martin Haft, Heinrich Saller

The discrete symmetries of the Lorentz group are on the one hand a `complex&#39; interplay between linear and anti-linear operations on spinor fields and on the other hand simple linear reflections of the Minkowski space. We define operations for T, CP and CPT leading to both kinds of actions. These operations extend the action of SL(2,C), representing the a

E. Bergshoeff, M. de Roo

We show how the $T$--duality between $D$--branes is realized (i) on $p$--brane solutions $(p=0,\cdots ,9)$ of IIA/IIB supergravity and (ii) on the $D$--brane actions ($p=0,\cdots ,3)$ that act as source terms for the $p$--brane solutions. We point out that the presence of a cosmological constant in the IIA theory leads, by the requirement of gauge invariance

Andrzej Sitarz

For a simplicial manifold we construct the differential geometry structure and use it to investigate linear connections, metric and gravity. We discuss and compare three main approaches and calculate the resulting gravity action functionals.

V. Ts. Gurovich, V. D. Dzhunushaliev

It is shown that the string equation can be obtain from field equations. Such work is performed to scalar field. The equation obtained in nonrelativistic limit describes the nonlinear string. Such string has the effective elasticity connencted with the local string curvature. Some examples of the movement such nonlinear elastic string are considered.

H. Yamada

We propose the use of Heaviside transform with respect to the quark mass to investigate dynamical aspects of QCD. We show that at large momentum transfer the transformed propagator of massive quarks behaves softly and thus the dominant effect of explicit chiral symmetry breaking disappears through Heaviside transform. This suggests that the massless approxim

Shijong Ryang

We realize the string/$(D-5)$-brane duality on the action level between the $T^{10-D}$-compactified heterotic string effective action and the $(D-5)$- brane effective action in $D$ dimensions by managing a Lagrange multiplier field. A dual dictionary is composed to be available for the translation between the elementary or solitonic solutions of the dual pai

G. L. Kane, James D. Wells

Motivated by the supersymmetric interpretation of the CDF eeγγplus missing energy event and the reported Z->bb excess at LEP, we analyze the Higgsino as a cold dark matter candidate. We examine the constraints as implied by the collider experiments, and then calculate its relic density. We find that this Higgsino-like lightest supersymmetric particle is a vi

J. R. Mureika, R. B. Mann

Some implications of the proposal that flavor nondiagonal couplings of neutrinos to gravity might resolve the solar neutrino problem are considered in the context of three neutrino flavors. The two--flavor model is discussed as a limiting case of the full three-generation mechanism, and the behavior of the $\nue$ survival probability for various values of th

D. Gomez Dumm

We study the evolution of fermion mass matrices considering the hypothesis of approximate flavor symmetries (AFS) in the Standard Model and a two-Higgs-doublet model. We find that the hierarchical structure is not significantly altered by the running, hence the assumption of AFS is entirely compatible with a grand unification scenario.