November 1997 arXiv papers — page 14

Peter Breitenlohner, George Lavrelashvili, Dieter Maison

The interior geometry of static, spherically symmetric black holes of the Einstein-Yang-Mills-Higgs theory is analyzed. It is found that in contrast to the Abelian case generically no inner (Cauchy) horizon is formed inside non-Abelian black holes. Instead the solutions come close to a Cauchy horizon but then undergo an enormous growth of the mass function,

Elena N. Selivanova

It has been proved that on 2-dimensional orientable compact manifolds of genus $g>1$ there is no integrable geodesic flow with an integral polynomial in momenta. There is a conjecture that all integrable geodesic flows on $T^2$ possess an integral quadratic in momenta. All geodesic flows on $S^2$ and $T^2$ possessing integrals linear and quadratic in momenta

A. W. Sandvik, S. Capponi, D. Poilblanc, E. Dagotto

The B1g Raman spectrum of the two-dimensional S=1/2 Heisenberg model is discussed within Loudon-Fleury theory at both zero and finite temperature. The exact T=0 spectrum for lattices with up to 6*6 sites is computed using Lanczos exact diagonalization. A quantum Monte Carlo (QMC) method is used to calculate the corresponding imaginary-time correlation functi

I. Safi, H. J. Schulz

We investigate transport through a finite interacting wire connected to noninteracting leads. The conductance of the pure wire is not renormalized by the interactions for any spatial variation of the interaction parameters $u,K$, and not even for Coulomb interactions restricted to the wire. We rigorously relate the conductance to the transmission, that turns

Darren J. T. Leonard, T. Portengen, V. Nikos Nicopoulos, Neil F. Johnson

We discuss the emergence of an orthogonality catastrophe in the response of a composite fermion liquid as the filling factor νapproaches 1/2m, where m=1,2,3.... A tunneling experiment is proposed in which dramatic changes in the I-V characteristic should be observable as νis varied. Explicit I-V characteristics calculated within the so-called Modified Random

M. Caselle, M. Hasenbusch

We study the stability of the O(N) fixed point in three dimensions under perturbations of the cubic type. We address this problem in the three cases $N=2,3,4$ by using finite size scaling techniques and high precision Monte Carlo simulations. It is well know that there is a critical value $2<N_c<4$ below which the O(N) fixed point is stable and above which t

E. Anisimovas, A. Matulis

We present the renormalized perturbation series for the energy spectrum of the parabolic quantum dot with 2 -- 5 electrons considering ground and the lowest excited states. The proper classification of asymptotic energy levels is performed and behaviour of energy levels from quantum to semiclassical regime is traced. Comparison between the present results an

Oliver Steffens, Ulrich Roessler, Michael Suhrke

We briefly report on calculated addition spectra for electrons in a circular quantum dot with perpendicular magnetic field. We compare our current density functional theory calculations with recent experiments by Tarucha et al. [PRL 77, 3613 (1996)]. We find a very good qualitative agreement of the structures and find an additional effect caused by Hund&#39;

G. E. Volovik

In our Comment (G.E. Volovik and V.M. Yakovenko, Phys. Rev. Lett. 79 (1997) 3792) to the Letter by W. Apel and Yu.A. Bychkov (Phys. Rev. Lett. 78 (1997) 2188) we questioned the derivation of the Hopf term in the hydrodynamic action for the Skyrmion dynamics in QHE. Our main argument was that the description in terms of Euler angles used by Apel and Bychkov w

Marko Robnik, Jure Dobnikar, Tomaz Prosen

Energy spectra of a particle with mass $m$ and charge $e$ in the cubic Aharonov-Bohm billiard containing around $10^4$ consecutive levels starting from the ground state have been analysed. The cubic Aharonov-Bohm billiard is a plane billiard defined by the cubic conformal mapping of the unit disc pervaded by a point magnetic flux through the origin perpendic

George B. Rybicki, Benjamin C. Bromley

The observed profile of spectral lines from a relativistic accretion disk can constrain parameters such as the disk geometry and the rotation of the central black hole. The formation of the spectral line in a disk generally has been modeled with simple assumptions such as local isotropy of emission. Here we consider line formation in the presence of velocity

William G. Mathews, Fabrizio Brighenti

We review recent progress in understanding the evolution of hot interstellar gas in the halos of elliptical galaxies. Non-homologous variations in the physical size of the hot gas account for the large variations of x-ray luminosity among ellipticals of similar L_B. By combining ROSAT and Einstein data we derive the distribution of total mass in NGC 4472. Fr

A. Crider, E. P. Liang, R. D. Preece

Recent studies have found that the spectral evolution of pulses within gamma-ray bursts (GRBs) is consistent with simple radiative cooling. Perhaps more interesting was a report that some bursts may have a single cooling rate for the multiple pulses that occur within it. We determine the probability that the observed &#34;cooling rate invariance&#34; is pure

A. Crider, E. P. Liang, R. D. Preece

The time-resolved spectra of gamma-ray bursts (GRBs) remain in conflict with many proposed models for these events. After proving that most of the bursts in our sample show evidence for spectral &#34;shape-shifting&#34;, we discuss what restrictions that BATSE time-resolved burst spectra place on current models. We find that the synchrotron shock model does

Greg Ushomirsky, Christopher D. Matzner, Edward F. Brown, Lars Bildsten

We present an analytic calculation of the thermonuclear depletion of the light elements lithium, beryllium, and boron in fully convective, low-mass stars. Under the presumption that the pre--main-sequence star is always fully mixed during contraction, we find that the burning of these rare light elements can be computed analytically, even when the star is de

Dong-Woo Kim, Giuseppina Fabbiano, Glen Mackie

We have observed NGC 1316 (Fornax A) with the ROSAT HRI. In this paper, we present the results of these observations and we complement them with the spectral analysis of the archival PSPC data. The spectral properties suggest the presence of a significant component of thermal X-ray emission (> 60%), amounting to ~10^{9}Mo of hot ISM. Within 3&#39; from the n

Carlo Baccigalupi

It is well known that processes of first order phase transitions may have occurred in the inflationary era. If one or more occurred well before the end of inflation, the nucleated bubbles are stretched to large scales and the primordial power spectrum contains a scale dependent non-Gaussian component provided by the remnants of the bubbles. We predict the an

R. Plaga

An extragalactic origin of the dominant part of all extrasolar hadronic cosmic rays above about 10 MeV/nucleon has long been considered unlikely due to energy considerations. In order to circumvent such arguments, the hypothesis that ``flux trapping&#39;&#39; of extragalactic cosmic rays occurs in the Galactic confinement volume is advanced in this paper. Th

Gaspar Galaz, Valerie de Lapparent

Using the ESO-Sculptor galaxy redshift survey data (ESS), we have extensively tested the Principal Components Analysis (PCA) method to perform the spectral classification of galaxies with $z \la$ 0.5. This method allows us to classify all galaxies in an ordered and continuous spectral sequence, which is strongly correlated with the morphological type. The PC

Chris Mihos

The onset of gaseous inflows and central activity in interacting galaxies is driven largely by induced bars in the host galaxies. The stability of galaxies against growing bar modes is a direct function of their structural properties --- galaxies with central bulges or low disk surface densities are more stable against central starbursts than are bulgeless o

A. Thorolfsson, O. E. Rognvaldsson, J. Yngvason, E. H. Gudmundsson

We present numerical calculations of the equation of state for dense matter in high magnetic fields, using a temperature dependent Thomas-Fermi theory with a magnetic field that takes all Landau levels into account. Free energies for atoms and matter are also calculated as well as profiles of the electron density as a function of distance from the atomic nuc

Uta Fritze - v. Alvensleben

Our unified chemical and spectrophotometric evolution code allows to simultaneously study the ISM abundances of a series of elements and the spectral properties of the stellar population in our model galaxies. We use stellar evolutionary tracks, yields, spectra, color and absorption index calibrations for 5 different metallicities and account for the increas

U. Fritze - v. Alvensleben, U. Lindner, K. J. Fricke

We use our unified chemical and spectrophotometric evolutionary synthesis code to describe galaxies of various Hubble types. With stellar evolutionary tracks and element yields for 5 different metallicities we follow the spectrophotometric evolution of composite stellar populations and the chemical evolution of ISM abundances in a chemically consistent way,

Uta Fritze - v. Alvensleben, Oliver Kurth

HST WFPC1 observations revealed 738 bright star clusters spread over the inner 12 kpc of the interacting galaxy pair NGC 4038/39. If the young star clusters (YSCs) formed in the global starburst are (proto-) globular or open clusters has far-reaching consequences for the formation of elliptical galaxies. Effective radii of the YSCs are difficult to measure o

S. Colombi, I. Szapudi, A. S. Szalay

The effects of sampling are investigated on measurements of counts-in-cells in three-dimensional magnitude limited galaxy surveys, with emphasis on moments of the underlying smooth galaxy density field convolved with a spherical window. A new estimator is proposed for measuring the k-th order moment < rho^k >: the weighted factorial moment F_k[w], corrected

K. C. Gendreau, X. Barcons, A. C. Fabian

An analysis of the spatial fluctuations in 15 deep ASCA SIS0 images has been conducted in order to probe the 2-10 keV X-ray source counts down to a flux limit 2E-14 erg/cm2/s. Special care has been taken in modelling the fluctuations in terms of the sensitivity maps of every one of the 16 regions (5.6 x 5.6 arcmin2 each) in which the SIS0 has been divided, b

P. Marigo, A. Bressan, C. Chiosi

In this paper we focus on the TP-AGB evolution of intermediate-mass stars experiencing envelope burning (M=4-5Mo). The approach we have adopted is a semi-analytical one as it combines analytical relationships derived from complete models of TP-AGB stars with sole envelope models in which the physical structure is calculated from the photosphere down to the c

Gerard van der Geer, Marcel van der Vlugt

In this note is we exhibit an elementary method to construct explicitly curves over finite fields with many points. Despite its elementary character the method is very efficient and can be regarded as a partial substitute for the use of class field theory.

R. P. Malik

We show the existence of a co(dual)-BRST symmetry for the usual BRST invariant Lagrangian density of an Abelian gauge theory in two dimensions of space-time where a U(1) gauge field is coupled to the Noether conserved current (constructed by the Dirac fields). Under this new symmetry, it is the gauge-fixing term that remains invariant and the symmetry transf

J. S. Bagla

We study the evolution of correlation function of dark matter halos in the CDM class of models. We show that the halo correlation function does not evolve in proportion with the correlation function of the underlying mass distribution. Earliest halos to collapse, which correspond to rare peaks in the density field, cluster very strongly. The amplitude of hal

Paul M. N. Feehan

The use of certain critical-exponent Sobolev norms is an important feature of methods employed by Taubes to solve the anti-self-dual and similar non-linear elliptic partial differential equations. Indeed, the estimates one can obtain using these critical-exponent norms appear to be the best possible when one needs to bound the norm of a Green&#39;s operator

Rob Clifton

John Bell once argued that one ought to select, out of the &#39;observables&#39; of quantum theory, some subset of &#39;beables&#39; that can be consistently ascribed determinate values. Moreover, this subset should be selected so as to guarantee (among other things) that we can dispense with the orthodox interpretation&#39;s loose talk about &#39;measuremen

I. N. Mishustin, L. M. Satarov, H. Stoecker, W. Greiner

Collective bremsstrahlung of vector meson fields in relativistic nuclear collisions is studied within the time-dependent Walecka model. Mutual deceleration of the colliding nuclei is described by introducing the effective stopping time and average rapidity loss of baryons. It is shown that electromagnetic decays of virtual omega-mesons produced by bremsstrah

Ferruccio Feruglio

I discuss the low-energy limit of several processes involving only ordinary particles and gravitinos. Astrophysical and laboratory applications are briefly addressed.

A. G. Grozin

HQET lagrangian up to $1/m^3$ terms is discussed. Consequences of reparameterization invariance are considered. Results for the chromomagnetic interaction coefficient at two loops, and in all orders in the large--$β_1$ approximation, are presented.

G. Blumberg, M. V. Klein, K. Kadowaki, C. Kendziora

For YBa_2Cu_3O_{6+δ} and Bi_2Sr_2CaCu_2O_8 superconductors, electronic Raman scattering from high- and low-energy excitations has been studied in relation to the hole doping level, temperature, and energy of the incident photons. For underdoped superconductors, it is concluded that short range antiferromagnetic (AF) correlations persist with hole doping and

Kiran M. Kolwankar, Anil D. Gangal

It has been recognized recently that fractional calculus is useful for handling scaling structures and processes. We begin this survey by pointing out the relevance of the subject to physical situations. Then the essential definitions and formulae from fractional calculus are summarized and their immediate use in the study of scaling in physical systems is g

Stephane Guilloteau, Alain Omont, Richard G. McMahon, Pierre Cox

We report the detection with the IRAM interferometer at 3mm of J=5-4 CO line in the radio quiet quasar BRI1335-0415 at redshift of z=4.41. After BR1202-0725 at z=4.69 (Ohta etal 1996, Omont etal 1996a), this is the second detection of CO at z>3. The integrated line intensity is 2.8+-0.3 Jy km s^{-1} with a linewidth of 420+-60 km s^{-1}. The dust continuum e

Xinwu Cao, D. R. Jiang, J. H. You, J. L. Zhao

A simplified frequency-integrated radiative transfer equation is solved to study Compton scatterings in the corona of the disk by using numerical iterating method. We find that the vertical thickness of the corona cannot be used as the typical length to measure the optical depth of the corona. A semi-analytical approach is proposed to calculate the energy di

Neta A. Bahcall

Clusters of galaxies, the most massive virialized systems known, provide a powerful tool for studying the structure, the mass density, and the cosmology of our universe. Clusters furnish one of the best estimates of the dynamical mass density parameter on 1 Mpc scale, $Ω_{dyn}$; the best measure of the baryon density fraction in the universe; an excellent tr

Boris Feigin, Michael Finkelberg, Alexander Kuznetsov, Ivan Mirković

For a simple algebraic group $G$ we study the space $Q$ of Quasimaps from the projective line $C$ to the flag variety of $G$. We prove that the global Intersection Cohomology of $Q$ carries a natural pure Tate Hodge structure, and compute its generating function. We define an action of the Langlands dual Lie algebra $g^L$ on this cohomology. We present a new

Nobuchika Okada

We present a simple model of gauge mediated supersymmetry breaking with composite messenger fields. Our model is based on the gauge group $Sp(8) \times SU(2)$. By the strong Sp(8) dynamics, supersymmetry is dynamically broken and the composite fields with charges under the standard model gauge group appear at low energy. The $U(1)_R$ symmetry breaking mass t

M. Hirata, K. Ochi, T. Takaki

We propose a resonance damping mechanism to explain the disappearance of the peaks around the position of the resonances higher than the $Δ$ resonance in the nuclear photoabsorption. This phenomenon is understood by taking into account the cooperative effect of the collision broadening of $Δ$ and $N^{*}$, the pion distortion and the interference in the two-p

Andre de Gouvea, Alexander Friedland, Hitoshi Murayama

We study the Next-to-Minimal Supersymmetric Standard Model (NMSSM) as the simplest candidate solution to the $μ$-problem in the context of the gauge mediation of supersymmetry breaking (GMSB). We first review various proposals to solve the $μ$-problem in models with the GMSB. We find none of them entirely satisfactory and point out that many of the scenarios

A. Patkos, P. Petreczky, Zs. Szep

Coupled 1-loop gap equations are studied numerically for non-Abelian electric and magnetic screening in various versions of the three-dimensional effective gauge models. Corrections due to higher dimensional and non-local operators are assessed quantitatively. Comparison with numerical Monte-Carlo investigations suggests that quantitative understanding beyon

Keiji matsumoto

In this paper, new methodology -- direct approach -- for the determination of the attainable CR type bound of the pure state model, is proposed and successfully applied to the wide variety of pure state models, for example, the 2-dimensional arbitrary model, the coherent model with arbitrary dimension. When the weight matrix is $SLD$ Fisher information, the

Maurice Kibler

This paper addresses the three following questions. (i) How the structures of group and of chain of groups enter nuclear, atomic and molecular spectroscopy? (ii) How these structures can be exploited, in a quantum- mechanical framework, in the problems of state labelling and (external) symmetry breaking? (iii) How it is possible to associate a Wigner-Racah a

Jerome Levine

A string link S can be closed in a canonical way to produce an ordinary closed link L. We also consider a twisted closing which produces a knot K. We give a formula for the Conway polynomial of L as a product of the Conway polynomial of K times a power series whose coefficients are given as explicit functions of the Milnor invariants of S. One consequence is

S. Das Gupta, A. Z. Mekjian

We use a simplified model which is based on the same physics as inherent in most statistical models for nuclear multifragmentation. The simplified model allows exact calculations for thermodynamic properties of systems of large number of particles. This enables us to study a phase transition in the model. A first order phase transition can be tracked down. T

P. -H. Heenen, J. Dobaczewski, W. Nazarewicz, P. Bonche

Recent experimental observation of the direct links between superdeformed and normal-deformed structures in the A~190 mass region offers a unique information on the absolute nuclear binding energy in the 2:1 minima, and hence on the magnitude of shell effects in the superdeformed well. In the present paper, the self-consistent mean-field theory with density-

Alexander Nabutovsky, Shmuel Weinberger

In this paper we introduce a new approach to variational problems on the space Riem(M^n) of Riemannian structures (i.e. isometry classes of Riemannan metrics) on any fixed compact manifold M^n of dimension n >= 5. This approach often enables one to replace the considered variational problem on Riem(M^n) (or on some subset of Riem(M^n)) by the same problem bu

C. Glenn Boyd, I. Z. Rothstein

By calculating the O(α_s) corrections to inclusive heavy-to-light sum rules we find model independent upper and lower bounds on form factors for B to pi and B to rho. We use the bounds to rule out model predictions. Some models violate the bounds only for certain ranges of sum rule input parameters \bar{lambda} \simeq m_B-m_b and lambda_1, or for certain cho

Konstantin Chetyrkin, Mikolaj Misiak, Manfred Muenz

We derive an algorithm for automatic calculation of perturbative $β$-functions and anomalous dimensions in any local quantum field theory with canonical kinetic terms. The infrared rearrangement is performed by introducing a common mass parameter in all the propagator denominators. We provide a set of explicit formulae for all the necessary scalar integrals

Mihir P. Worah

We explore the possibility of using CP violation in B decays to detect the presence of physics beyond the Standard Model. We first study the possibility of new physics in the $B-\bar B$ mixing amplitude. We discuss a construction to extract information about the phase and magnitude of the new physics contribution, as well as the CKM parameters in a model ind

MILC Collaboration, Claude Bernard, Tom DeGrand, Carleton DeTar

We report on a study of the light quark spectrum using an improved gauge action and both Kogut-Susskind and Naik quark actions. We have studied six different lattice spacings, corresponding to plaquette couplings ranging from 6.8 to 7.9, with five to six quark masses per coupling. We compare the two quark actions in terms of the spectrum and restoration of f

Yasuhiro Hieida

We apply the density matrix renormalization group (DMRG) method to a non-equilibrium problem: the asymmetric exclusion process in one dimension. We study the stationary state of the process to calculate the particle density profile (one-point function). We show that, even with a small number of retained bases, the DMRG calculation is in excellent agreement w

Hiroyuki Fukuda, Keiichi Wada, Asao Habe

When a supermassive black hole exists in the centre of a galaxy, an additional inner Lindblad resonance (ILR) exists inside the usual ILRs. We study gas dynamics in a weakly barred potential with a central supermassive black hole by using 2D numerical simulations, and we investigate the effect of the additional ILR on fuelling gas into nuclear starburst regi

George Smoot, Douglas Scott

We summarise the current status of cosmic microwave background spectrum and anisotropy measurements, and their theoretical interpretation. This is the update of the mini-review for the 1997 web-version of the Review of Particle Properties.

Michael Graesser, Bogdan Morariu

We show that the holomorphic Wilsonian beta-function of a renormalizable asymptotically free supersymmetric gauge theory with an arbitrary semi-simple gauge group, matter content, and renormalizable superpotential is exhausted at 1-loop with no higher loops and no non-perturbative contributions. This is a non-perturbative extension of the well known result o

Mehran Kardar, Ramin Golestanian

The static Casimir effect describes an attractive force between two conducting plates, due to quantum fluctuations of the electromagnetic (EM) field in the intervening space. {\it Thermal fluctuations} of correlated fluids (such as critical mixtures, super-fluids, liquid crystals, or electrolytes) are also modified by the boundaries, resulting in finite-size

C. - W. H. Lee, S. G. Rajeev

We obtain the symmetry algebra of multi-matrix models in the planar large N limit. We use this algebra to associate these matrix models with quantum spin chains. In particular, certain multi-matrix models are exactly solved by using known results of solvable spin chain systems.

John D. Barrow, Mariusz P. Dabrowski

Bianchi type IX, &#39;Mixmaster&#39; universes are investigated in low-energy-effective-action string cosmology. We show that, unlike in general relativity, there is no chaos in these string cosmologies for the case of the tree-level action. The characteristic Mixmaster evolution through a series of Kasner epochs is studied in detail. In the Einstein frame a

Andrzej J. Buras, Robert Fleischer, Thomas Mannel

In the recent literature, constraints on the CKM angle $\gamma$ arising from the branching ratios for $B^\pm\to\pi^\pm K$ and $B_d\to\pi^\mp K^\pm$ decays received a lot of attention. An important theoretical limitation of the accuracy of these bounds is due to rescattering effects, such as $B^+\to\{\pi^0K^+\}\to\pi^+K^0$. We point out that these processes a

Nathan Roche, Stephen Eales, Hans Hippelein

We investigate the angular correlation function, $ω(θ)$, of the galaxi es detected in the K-band on 17 fields (101.5 square arcmin in total), each containing a $z\sim 1.1$ radio galaxy. There is a significant detection of galaxy clustering at $K\sim 20$ limits, with an amplitude higher than expected from simple models which fit the faint galaxy clustering in

Boris Tomasik, Ulrich Heinz, Jan Pisut

We argue that strong final state rescattering among the secondary particles created in relativistic heavy ion collisions is essential to understand the measured Bose-Einstein correlations. The recently suggested ``random walk models&#39;&#39; which contain only initial state scattering are unable to reproduce the measured magnitude and K_\perp-dependence of

Han-Yong Choi

The suppressed NMR coherence peak in the fullerene superconductors is explained in terms of the dampings in the superconducting state induced by the Coulomb interaction between conduction electrons. The Coulomb interaction, modelled in terms of the onsite Hubbard repulsion, is incorporated into the Eliashberg theory of superconductivity with its frequency de

Masanao Ozawa

A rigorous theory of quantum state reduction, the state change of the measured system caused by a measurement conditional upon the outcome of measurement, is developed fully within quantum mechanics without leading to the vicious circle relative to the von Neumann chain. For the basis of the theory, the local measurement theorem provides the joint probabilit

Giulio Peruzzi, Alberto Rimini

We illustrate two simple spin examples which show that in the consistent histories approach to quantum mechanics one can retrodict with certainty incompatible or contradictory propositions corresponding to non-orthogonal or, respectively, orthogonal projections. V.2 vs. V1: The example previously quoted as &#34;d&#39;Espagnat&#39;s example&#34; is now proper

Chongying Dong, Robert L. Griess

Let L be a positive definite even lattice of rank one and V_L^+ be the fixed points of the lattice VOA V_L associated to L under an automorphism of V_L lifting the -1$ isometry of L. A set of generators and the full automorphism group of V_L^+ are determined.

C. A. Bertulani, M. S. Hussein, M. P. Pato, M. Ueda

We study the postacceleration of charged fragments in reactions with unstable nuclear beams. For elastic breakup processes we show that the postaceleration effect can be well understood in terms of closed analytical forms derived in a quantum mechanical formulation. This gives theoretical support to the effect experimentally observed in the breakup of Li-11

S. Jeschonnek, T. W. Donnelly

We employ a recent approach to the non-relativistic reduction of the electromagnetic current operator in calculations of electronuclear reactions. In contrast to the traditional scheme, where approximations are made for the transferred momentum, transferred energy and initial momentum of the struck nucleon in obtaining an on-shell inspired form for the curre

S. Takami, K. Yabana, M. Matsuo

We study static non-axial octupole deformations in proton-rich $Z=N$ nuclei, $^{64}$Ge, $^{68}$Se, $^{72}$Kr, $^{76}$Sr, $^{80}$Zr and $^{84}$Mo, by using the Skyrme Hartree-Fock plus BCS calculation with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in $^{68}$Se is extremely soft for the $Y_{33}$ triangular defo

R. Nouicer, C. Beck, S. J. Sanders, A. Szanto de Toledo

Fragment-fragment-$γ$ triple coincident measurements of the $^{28}$Si + $^{28}$Si reaction at E$_{lab.}$ = 111.6 MeV carefully chosen to populate J = 38$^{+}$ resonance have been performed at the VIVITRON tandem facility by using Eurogam Phase II $γ$-ray spectrometer. In the $^{28}$Si + $^{28}$Si exit-channel, the resonance behavior of the $^{28}$Si + $^{28}

NA49 Collaboration, H. Appelshaeuser et al

The directed and elliptic flow of protons and charged pions has been observed from the semi-central collisions of a 158 GeV/nucleon Pb beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons but both exhibit negative flow at low pt. The elliptic fl

Juan Maldacena, Andrew Strominger, Edward Witten

Extremal black holes in M-theory compactification on $M\times S^1$ are microscopically represented by fivebranes wrapping $P\times S^1$, where $M$ is a Calabi-Yau threefold and $P$ is a four-cycle in $M$. Additional spacetime charges arise from momentum around the $S^1$ and expectation values for the self-dual three-form field strength in the fivebrane. The

B. Geyer, D. M&#34;ulsch

Nonabelian gauge theories with a generic background field A_mu in nonlinear gauges due to Delbourgo and Jarvis are investigated. The A_mu-dependence is completely determined by the help of a linear differential equation which obtaines from the Kluberg-Stern-Zuber and the Lee identity. Its integration leads to a relation between the one-particle irreducible v

Riccardo D&#39;Auria, Sergio Ferrara, Costas Kounnas

Decomposition of the solvable Lie algebras of maximal supergravities in D=4, 5 and 6 indicates, at least at the geometrical level, the existence of an N=(4,2) chiral supergravity theory in D=6 dimensions. This theory, with 24 supercharges, reduces to the known N=6 supergravity after a toroidal compactification to D=5 and D=4. Evidence for this theory was giv

Poul H. Damgaard

Massive spectral sum rules are derived for Dirac operators of $SU(N_c)$ gauge theories with $N_f$ flavors. The universal microscopic massive spectral densities of random matrix theory, where known, are all consistent with these sum rules.

P. Paganini, F. Parodi, P. Roudeau, A. Stocchi

A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix ($V_{CKM}$) is presented and a special emphasis is put on the determination of the $ρ$ and $η$ parameters. From this study it follows that, in the Standard Model, the $B^0_s$-$\bar{B^0_s}$ oscillation frequency, $Δm_s$, has to lie, with 68% C.L., between 6.5 ps$^{-1}$ and 15 ps$^{-1}$, an

Yuichiro Kiyo, Jiro Kodaira, Hiroshi Tochimura

The small $x$ behavior of the flavor non-singlet $g_{1}$ structure function is analysed numerically by taking into account the all-order resummation of $α_{s} \ln^{2}x $ terms. We include a part of the next-to-leading logarithmic corrections coming from the resummed ``coefficient function&#39;&#39; which are not considered in the literatures to respect the f

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

A new study is reported of a lattice QCD calculation of the $K^+\toπ^+ π^0 $ decay amplitude with the Wilson quark action in the quenched approximation at $β=6.1$. The amplitude is extracted from the $K\toππ$ Green function, and a conversion to the continuum value is made employing a recent one-loop calculation of chiral perturbation theory. The result is co

R. Casadio, B. Harms, Y. Leblanc

The thermodynamical description of black holes is reviewed and critiqued. We present an alternative, microcanonical description of black holes and discuss the major differences. In particular the decay rates of black holes are compared in the two different pictures.

Carlo Rovelli

The space of the solutions of Dirac&#39;s quantum constraints cannot be constructed factoring the quantum state space by the ``simple&#39;&#39; gauge transformations generated by the constraints. However, we show here that it can be constructed by factoring the state space by suitably defined ``complete&#39;&#39; gauge transformations. These are generated by

Stephen Parrott

A recent paper of Singal [Gen. Rel. Grav. 27 (1995), 953-967] argues that a uniformly accelerated particle does not radiate, in contradiction to the consensus of the research literature over the past 30 years. This note points out some questionable aspects of Singal&#39;s argument and shows how similar calculations can lead to the opposite conclusion.

Michel Brion, Michèle Vergne

We present a simple proof of a precise version of the localization theorem in equivariant cohomology. As an application, we describe the cohomology algebra of any compact symplectic variety with a multiplicity-free action of a compact Lie group. This applies in particular to smooth, projective spherical varieties.

Dmitrii L. Maslov, Paul M. Goldbart

Reflection of charge excitations at the step in the interaction strength in a Luttinger liquid can be of the Andreev type, even if the interactions are purely repulsive. The region with stronger repulsion plays the role of a normal metal in a normal-metal /superconductor junction, whereas the region with weaker repulsion plays the role of a superconductor. I

S. A. Larin, M. Moennigmann, M. Stroesser, V. Dohm

We present an analytic five-loop calculation for the additive renormalization constant A(u,epsilon) and the associated renormalization-group function B(u) of the specific heat of the O(n) symmetric phi^4 theory within the minimal subtraction scheme. We show that this calculation does not require new five-loop integrations but can be performed on the basis of

V. Hizhnyakov, D. Nevedrov

We examine quantum decay of localized vibrations in anharmonic crystal lattice. The theory which describes two-phonon anharmonic relaxation can be applied both to local modes associated with substitutional impurity and to intrinsic local modes (ILM) in perfect lattices. It is found that for sufficiently high initial excitations relaxation of vibrations is no

V. Hizhnyakov, D. Nevedrov

The two-phonon decay of self-localized soliton in a one-dimensional monatomic anharmonic lattice caused by cubic anharmonicity is considered. It is shown that the decay takes place with emission of phonon bursts. The average rate of emission of phonons is of the order of vibrational quantum per vibrational period. Characteristic time of the relaxation is det

N. B. Wilding, M. Krech

A solid substrate, when exposed to a vapour, can interact with it in such a way that sufficiently close to liquid-vapour coexistence a macroscopically thick liquid wetting layer is formed on the substrate surface. If such a wetting transition occurs for a binary fluid mixture in the vicinity of the critical end point of demixing transitions, critical fluctua

S. Giorgini, L. P. Pitaevskii, S. Stringari

We find that the fluctuations of the condensate in a weakly interacting Bose gas confined in a box of volume $V$ follow the law $<δN_0^2>\sim V^{4/3}$. This anomalous behaviour arises from the occurrence of infrared divergencies due to phonon excitations and holds also for strongly correlated Bose superfluids. The analysis is extended to an interacting Bose

Johannes Voit

I discuss origin and possible experimental manifestations of charge-spin separation in 1D Luttinger and Luther-Emery liquids, the latter describing 1D Mott and Peierls insulators and superconductors. Emphasis is on photoemission where the spectral function generically shows two dispersing peaks associated with the collective charge and spin excitations, and

Tomasz Krzyszton

The intrinsic pinning in high-temperature superconductor with long range antiferromagnetic order of rare-earth ions confined to the isolating planes is described. The interaction of antiferromagnetic and superconducting subsystems in the mixed state may lead to the creation of spin-flop domain along the vortex core. It is shown that the behavior of several p

Takao Kotani

We present a new density-functional method of the self-consistent electronic-structure calculation which does not exploit any local density approximations (LDA). We use the exchange-correlation energy which consists of the exact exchange and the correlation energies in the random-phase approximation. The functional derivative of the correlation energy with r

A. Koga, S. Kumada, N. Kawakami, T. Fukui

We investigate low-energy properties of a generalized spin ladder model with both of the spin alternation and the bond alternation, which allows us to systematically study not only ladder systems but also alternating spin chains. By exploiting non-linear $σ$ model techniques we study the model with particular emphasis on the competition between gapful and ga

Awadhesh Prasad, Vishal Mehra, Ramakrishna Ramaswamy

Different mechanisms for the creation of strange non-chaotic dynamics in the quasiperiodically forced logistic map are studied. These routes to strange nonchaos are characterised through the behavior of the largest nontrivial Lyapunov exponent, as well as through the characteristic distributions of finite time Lyapunov exponents. Strange nonchaotic attractor

S. R. Heap, T. M. Brown, I. Hubeny, W. Landsman

An echelle spectrogram (R = 30,000) of the 2300-3100 A region in the ultraviolet spectrum of the F8V star 9 Comae is presented. The observation is used to calibrate features in the mid-ultraviolet spectra of similar stars according to age and metal content. In particular, the spectral break at 2640 A is interpreted using the spectral synthesis code SYNSPEC.

F. Sylos Labini, M. Montuori, L. Pietronero

Some years ago we proposed a new approach to the analysis of galaxy and cluster correlations based on the concepts and methods of modern statistical Physics. This led to the surprising result that galaxy correlations are fractal and not homogeneous up to the limits of the available catalogs. The usual statistical methods, which are based on the assumption of

Alberto Buzzoni

A theoretical approach relying on evolutionary population synthesis models could help refining the search criteria in deep galaxy surveys on the basis of a better knowledge of the expected apparent photometric properties of high-redshift objects. The following is a brief discussion reviewing some relevant aspects of the question in order to allow a more crit

M. Ehle, W. Pietsch, R. Beck, U. Klein

The nearly face-on SBc galaxy M83 (NGC 5236) was observed for 25 ksec with the ROSAT PSPC. We detected 13 point-like sources in this galaxy, 10 of which were previously unknown. We measured extended X-ray radiation from almost the whole optically visible galaxy. Comparing the diffuse soft and hard X-ray emission components, we observed a different asymmetric