January 1996 arXiv papers — page 2

Michael S. Vogeley, Alexander S. Szalay

We describe a method for estimating the power spectrum of density fluctuations from galaxy redshift surveys that yields improvement in both accuracy and resolution over direct Fourier analysis. The key feature of this analysis is expansion of the observed density field in the unique set of statistically orthogonal spatial functions which obtains for a given

James E. Rhoads, Sangeeta Malhotra, Tomislav Kundic

We report the detection of a very red source coincident with the gravitational lens 1938+66.6 (Patnaik et al. 1992) in K' (2.12 micron), H (1.6 micron), J (1.25 micron), and Thuan-Gunn r (0.65 micron) bands. 1938+66.6 has previously been detected as a partial radio ring indicating lensing. We find K'=17.1 +- 0.1 and r = 23.9 +- 0.2, making it a very

G. L. Hoffman, E. E. Salpeter, B. Farhat, T. Roos

Neutral hydrogen mapping of 70 dwarf irregular (Sm, Im and BCD) galaxies is reported, with position-velocity contour maps presented for those resolved by the Arecibo beam. The galaxies were selected either from the Virgo Cluster Catalog, from similarly identified field galaxies, or from a distance-limited sample within the Arecibo declination range. We do no

T. Passot, E. Vazquez-Semadeni, A. Pouquet

We present results from two-dimensional numerical simulations of a supersonic turbulent flow in the plane of the galactic disk, incorporating shear, thresholded and discrete star formation (SF), self-gravity, rotation and magnetic fields. A test of the model in the linear regime supports the results of the linear theory of Elmegreen (1991). In the fully nonl

J. Lehar, A. J. Cooke, C. R. Lawrence, A. D. Silber

We have measured a velocity dispersion for the foreground galaxy in this gravitationally lensed system. Our dispersion confirms the prediction from lens models, provided that the source is distant enough ($z_{_S}>0.2$). Current interpretations of lensing statistics depend sensitively on how the optical and mass dispersions are related. For $z_{_S}>0.5$, our

Greg P. Kochanski, J. Anthony Tyson, Philippe Fischer

Optical variability in galaxies at high redshift is a tracer of evolution in AGN activity, and should provide a useful constraint on models of galaxy evolution, AGN structure, and cosmology. We studied optical variability in multiple deep CCD and photographic surveys of blank fields for galaxies with $B_j = 20 - 25$ mag. Weakly variable objects are far more

A. Kogut, G. Hinshaw

Recent detections of cosmic microwave background (CMB) anisotropy at half-degree angular scales show considerable scatter in the reported amplitude even at similar angular resolution. We use Monte Carlo techniques to simulate the current set of medium-scale CMB observations, including all relevant aspects of sky coverage and measurement technique. The scatte

J. P. Norris, R. J. Nemiroff, J. T. Bonnell, J. D. Scargle

Two tests for cosmological time dilation in $γ$-ray bursts -- the peak alignment and auto-correlation statistics -- involve averaging information near the times of peak intensity. Both tests require width corrections, assuming cosmological origin for bursts, since narrower temporal structure from higher energy would be redshifted into the band of observation

J. P. Norris, J. T. Bonnell, R. J. Nemiroff, J. D. Scargle

If $γ$-ray bursts are at cosmological distances, then not only their constituent pulses but also the intervals between pulses should be time-dilated. Unlike time-dilation measures of pulse emission, intervals would appear to require negligible correction for redshift of narrower temporal structure from higher energy into the band of observation. However, str

A. Fernandez-Soto, K. M. Lanzetta, X. Barcons, R. F. Carswell

We use new observations of very weak CIV absorption lines associated with high-redshift Lyman-alpha absorption systems to measure the high-redshift Lyman-alpha line two-point correlation function (TPCF). These very weak CIV absorption lines trace small-scale velocity structure that cannot be resolved by Lyman-alpha absorption lines. We find that (1) high-red

Eric Tessier

From natural guide star adaptive optics data taken with the Come-On Plus and with the Starfire Optical Range Generation II instruments in the JHK bands and in the I band respectively, we describe and analyse the point spread function. The ultimate exploitation of adaptive optics images requires the deconvolution and therefore the calibration of the point spr

Takamitsu Miyaji, Guenther Hasinger, Roland Egger, Joachim Truemper

We have made cross-correlation analyses of (2 -- 15 keV) HEAO A2 and 1 keV ROSAT PSPC All-Sky Survey maps over a selected area ($\sim$ 4000 deg$^2$) with high galactic latitude (b>40 deg). We have calculated the correlations for the bright ROSAT sources and residual background separately with the \HEAO A2 TOT (2 -- 10 keV) and HRD (5 -- 15 keV) maps. The amp

Sabino Matarrese

The general relativistic non--linear dynamics of a self--gravitating collisionless fluid with vanishing vorticity is studied in synchronous and comoving -- i.e. {\em Lagrangian} -- coordinates. Writing the equations in terms of the metric tensor of the spatial sections orthogonal to the fluid flow allows an unambiguous expansion in inverse powers of the spee

J. P. Norris

Understanding the bimodal duration distribution (dynamic range $>$ 10$^{4}$) of $γ$-ray bursts is central to determining if the phenomenon is in fact a singular one. A unifying concept, beyond isotropy and inhomogeneity of the two groups separately, is that bursts consist of pulses, organized in time and energy: wider pulses are more asymmetric, their centro

Martin White, Douglas Scott

The COBE detection of microwave anisotropies provides the best way of fixing the amplitude of cosmological fluctuations on the largest scales. We discuss the impact of this new, precise normalization and give fitting formulae for the horizon-crossing amplitude as a function of Ω_0 and n for both open and flat cosmologies. We also discuss the relevant normali

Paul Goudfrooij

Results from IRAS and recent optical CCD surveys are examined to discuss the distribution and origin of dust and ionized gas in elliptical galaxies. In strong contrast with the situation among spiral galaxies, masses of dust in elliptical galaxies as derived from optical extinction are an order of magnitude LOWER than those derived from IRAS data. I find tha

The BAIKAL Collaboration

The deep underwater Cherenkov neutrino telescope NT-200 is currently under construction at Lake Baikal. The "subdetectors" NT-36 (1993-95) and NT-72 (1995-96) have been operating successfully over 3 years. Various techniques have been developed to search for magnetic monopoles with these arrays. Here we describe a method used to detect superheavy slo

P. Bialas, Z. Burda, A. Krzywicki, B. Petersson

Our earlier renormalization group analysis of simplicial gravity is extended. A high statistics study of the volume and coupling constant dependence of the cumulants of the node distribution is carried out. It appears that the phase transition of the theory is of first order, contrary to what is generally believed.

L. Dixon

We review techniques for more efficient computation of perturbative scattering amplitudes in gauge theory, in particular tree and one-loop multi-parton amplitudes in QCD. We emphasize the advantages of (1) using color and helicity information to decompose amplitudes into smaller gauge-invariant pieces, and (2) exploiting the analytic properties of these piec

Sergey Solodukhin

We discuss the connection between different entropies introduced for black hole. It is demonstrated on the two-dimensional example that the (quantum) thermodynamical entropy of a hole coincides (including UV-finite terms) with its statistical-mechanical entropy calculated according to 't Hooft and regularized by Pauli-Villars.

Stephen E. Zepf, Joseph Silk

We consider the hypothesis that the formation of elliptical galaxies includes a phase in which star formation is mostly restricted to massive stars, with the bias towards high mass stars increasing with elliptical galaxy mass. The mass fraction of stars in this top-heavy mode of star formation is constrained by requiring the resulting stellar remnants to acc

J. A. Casas, A. Lleyda, C. Muñoz

The general constraints on the parameter space of soft-breaking terms, in order to avoid dangerous charge and color breaking minima, are applied to the four-dimensional string scenario where the dilaton is the source of supersymmetry breaking (dilaton-dominated limit). The results indicate that the whole parameter space is excluded on these grounds after imp

Andrew Steane

The concept of multiple particle interference is discussed, using insights provided by the classical theory of error correcting codes. This leads to a discussion of error correction in a quantum communication channel or a quantum computer. Methods of error correction in the quantum regime are presented, and their limitations assessed. A quantum channel can r

E. Stein, M. Meyer-Hermann, L. Mankiewicz, A. Schäfer

The available data on $F_L$ suggest the existence of unexpected large higher twist contributions. We use the $1/N_f$ expansion to analyze the renormalon contribution to the coefficient function of the longitudinal structure function $F_L^{p-n}$. The renormalon ambiguity is calculated for all moments of the structure function thus allowing to estimate the con

Ivo Saviane, Enrico V. Held, Giampaolo Piotto

We present $V$ and $I$ CCD photometry for $\sim360$ stars in the recently discovered dwarf galaxy Tucana. The large field investigated and the accurate photometric calibration make our data complementary to the deeper HST photometry. From the $I$ magnitude of the tip of the red giant branch we estimate a distance modulus $(m-M)_0=24.69\pm0.16$, corresponding

Jonathan Wahl

For a smooth subvariety $X\subset\Bbb P^N$, consider (analogously to projective normality) the vanishing condition $H^1(\Bbb P^N,\Cal I^2_X(k))=0$, $k\ge3$. This condition is shown to be satisfied for all sufficiently large embeddings of a given $X$, and for a Veronese embedding of $\Bbb P^n$. For $C\subset\Bbb P^{g-1}$, the canonical embedding of a non-hype

The Baikal Collaboration

The deep underwater Cherenkov neutrino telescope NT-200 is currently under construction at lake Baikal. Its first stage NT-36 consisting of 36 optical modules has operated over 2 years since April 1993 till March 1995. Here we present a method to search for nearly vertical upward going muons from neutralino annihilation in the center of the Earth. We present

A. Vogt

We analyze the capability of charm production in deep-inelastic ep scattering at HERA to constrain the gluon distribution g(y,\mu^2) of the proton. The dependence of the theoretical predictions for the charm structure function F_2^c on the mass factorization scale \mu and the charm mass is investigated. F_2^c seems to be well suited for a rather clean and lo

T. Doerrer, H. Riffert, R. Staubert, H. Ruder

Radiation emitted from an accretion disk around a massive black hole is a widely discussed model for the UV/soft X-ray excess emission observed in the spectra of many AGN. A self-consistent calculation of the structure and the emerging spectrum of geometrically thin alpha-accretion disks in AGN is presented. The central object is assumed to be a Kerr black h

P. Prelovsek, J. Jaklic

The resonant part of the $B_{1g}$ electronic Raman scattering response is calculated within the $t-J$ model on a planar lattice as a function of temperature and hole doping, using a finite-temperature diagonalization method for small systems. Results, directly applicable to experiments on cuprates, reveal on doping a very pronounced increase of the width of

H. David Politzer

The computer code on which this paper relied contained an error. When corrected, the Monte Carlo evaluation of the ground state occupation is consistent with the conventional grand canonical calculation. Hence, the original version of this paper has been withdrawn.

H. David Politzer

The computer code on which this paper relied contained an error. When corrected, the Monte Carlo evaluation of the ground state occupation is consistent with the conventional grand canonical calculation. Hence, the original version of this paper has been withdrawn.

David Jasnow, Jorge Vinals

A mesoscopic or coarse-grained approach is presented to study thermo-capillary induced flows. An order parameter representation of a two-phase binary fluid is used in which the interfacial region separating the phases naturally occupies a transition zone of small width. The order parameter satisfies the Cahn-Hilliard equation with advective transport. A modi

M. J. Mehl, L. L. Boyer, H. T. Stokes

This is a brief description of how to derive the local ``atomic'' potentials from the Self-Consistent Atomic Deformation (SCAD) model density function. Particular attention is paid to the spherically averaged case.

V. A. Kazakov, M. Staudacher, T. Wynter

We review the recent exact solution of a matrix model which interpolates between flat and random lattices. The importance of the results is twofold: Firstly, we have developed a new large N technique capable of treating a class of matrix models previously thought to be unsolvable. Secondly, we are able to make a first precise statement about two-dimensional

J. D. Bjorken

A simple semiquantitative picture of diffractive electroproduction is described. Although the diffractive component of $F_2$ is approximately independent of $Q^2$ and $W^2$, this mechanism is "soft," i.e. it depends upon large-distance physics and is not readily describable within perturbative QCD.

Daniel R. Stump, Michael Wiest, C. -P. Yuan

If supersymmetry is dynamically broken at a low scale ($M_{susy}$), within a few orders of magnitude of the weak scale, then the lightest supersymmetric partner is the gravitino and the next to lightest supersymmetric partner is a neutralino $χ^0_1$ with mass $m_{χ^0_1}$, which can decay into a photon ($γ$) plus a gravitino ($\widetilde{G}$). We study the de

N. Evans, S. D. H. Hsu, M. Schwetz

We discuss the global symmetries of the high temperature phase of QCD with $N_f$ massless quarks. We show that the $U(N_f) \times U(N_f)$ symmetries are only violated by operators of dimension $\geq 3 N_f$. For $N_f > 2$ this implies that the thermal two-point correlation functions of the $η'$ and $π^a$'s are identical. We discuss the implications of

Peter Cho, Mikolaj Misiak, Daniel Wyler

The flavor changing neutral current processes $K_L \to π^0 e^+ e^-$, $B \to X_s e^+ e^-$ and $B \to X_s μ^+ μ^-$ are studied within the minimal supersymmetric extension of the Standard Model. We first examine the rates for these decay modes in the MSSM with a universal soft supersymmetry breaking sector at a Grand Unification scale. We later relax the univer

Gia Dvali, Stefan Pokorski

Within the supersymmetric SO(10) GUT we explore the possibility of the light Higgs doublet being a member of the 16-dimensional spinorial representation. This fact is ultimately related with the assumption that the light matter (at least partially) resides in some of the tensor representations as well. Several interesting features emerge. First, provided tha

A. Denner, S. Dittmaier, R. Schuster

We discuss the complete virtual and soft-photonic O(alpha) corrections to AA -> W+W- within the electroweak Standard Model for arbitrary polarized photons. In the on-shell renormalization scheme for fixed M_W no leading corrections associated with the running of alpha or heavy top-quark and Higgs-boson masses occur. The corrections turn out to be of the orde

E. Alfinito, M. Blasone, A. Iorio, G. Vitiello

We show that the generator of field mixing transformations in Quantum Field Theory induces a non trivial structure in the vacuum which turns out to be a coherent state, both for bosons and for fermions, although with a different condensate structure. The Fock space for mixed fields is unitarily inequivalent to the Fock space of the massive (free) fields in t

L. Ya. Glozman, Z. Papp, W. Plessas

It is shown from rigorous three-body Faddeev calculations that the masses of all 14 lowest states in the $N$ and $Δ$ spectra can be described within a constituent quark model with a Goldstone-boson-exchange interaction plus linear confinement between the constituent quarks.

T. Sjostrand, J. K. Storrow, A. Vogt

Recent progress on the parton distribution functions of the photon, both real and virtual, is briefly reviewed and experimental possibilities at HERA are discussed.

Craig Pryor

The phase diagram of an SU(2)_L x SU(2)_R lattice Higgs-Yukawa model with finite lambda is constructed using mean field theory. The phase diagram bears a superficial resemblance to that for infinite lambda, however as lambda is decreased the paramagnetic region shrinks in size. For small lambda the phase transitions remain second order, and no new first orde

UKQCD Collaboration

The results of an exploratory lattice study of heavy baryon spectroscopy are presented. We have computed the full spectrum of the eight baryons containing a single heavy quark, on a $24^3\times 48$ lattice at $β=6.2$, using an $O(a)$-improved fermion action. We discuss the lattice baryon operators and give a method for isolating the contributions of the spin

M. M. Tsypin

We compute the effective potential $V_{\rm eff}(ϕ)$ for one-component real scalar field $ϕ$ in three Euclidean dimensions (3D) in the case of spontaneously broken symmetry, from the Monte Carlo simulation of the 3D Ising model in external field at temperatures approaching the phase transition from below. We study probability distributions of the order parame

M. Billo', M. Caselle, A. D'Adda, S. Panzeri

We consider the SU(2) lattice gauge theory at finite temperature in (d+1) dimensions, with different couplings $β_t$ and $β_s$ for timelike and spacelike plaquettes. By using the character expansion of the Wilson action and performing the integrals over space-like link variables, we find an effective action for the Polyakov loops which is exact to all orders

John D. Stack, Steven D. Neiman

Confinement via 't Hooft-Mandelstam monopoles is studied for the positive plaquette model in SU(2) lattice gauge theory. Positive plaquette model configurations are projected into the maximum abelian gauge and the magnetic current extracted. The resulting magnetic current is used to compute monopole contributions to Wilson loops and extract a monopole co

F. Abe

The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | η| \leq $0.7. The results are based on 19.5 pb$^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton

James B. Hartle

Existing physical theories do not predict every feature of our experience but only certain regularities of that experience. That difference between what could be observed and what can be predicted is one kind of limit on scientific knowledge. Such limits are inevitable if the world is complex and the laws governing the regularities of that world are simple.

David Hochberg, Sergey V. Sushkov

An approximate form for the vacuum averaged stress-energy tensor of a conformal spin-2 quantum field on a black hole background is employed as a source term in the semiclassical Einstein equations. Analytic corrections to the Schwarzschild metric are obtained to first order in $ε= {\hbar}/M^2$, where $M$ denotes the mass of the black hole. The approximate te

T. Shirafuji, G. G. L. Nashed, K. Hayashi

We find the most general, spherically symmetric solution in a special class of tetrad theory of gravitation. The tetrad gives the Schwarzschild metric. The energy is calculated by the superpotential method and by the Euclidean continuation method. We find that unless the time-space components of the tetrad go to zero faster than ${1/\sqrt{r}}$ at infinity, t

Eugene Lerman

In this paper I construct, using off the shelf components, a compact symplectic manifold with a non-trivial Hamiltonian circle action that admits no Kaehler structure. The non-triviality of the action is guaranteed by the existence of an isolated fixed point. The motivation for this work comes from the program of classification of Hamiltonian group actions.

Haranath Ghosh, Manas Sardar

Experimentally, Raman continuum for $A_g$ and $B_g$ geometry exhibits peaks far apart from each other (about 80 to 150 $\rm cm^{-1}$) in frequency. The former is insensitive to doping over a small range where $T_c$ does not vary much whereas the latter shifts towards higher frequencies. We calculate the electronic Raman scattering intensities using the `modi

Macoto Kikuchi, Yutaka Okabe

The multi-spin coding of the Monte Carlo simulation of the three-state Potts model on the simple cubic lattice is presented. The ferromagnetic (F) model, the antiferromagnetic (AF) model, and the random mixture of the F and AF couplings are treated. The multi-spin coding technique is also applied to the block-spin transformation. The block-spin transformatio

S. S. Manna, B. Subramanian

We consider a model for the formation of a river network in which erosion process plays a role only at the initial stage. Once a global connectivity is achieved, no further evolution takes place. In spite of this, the network reproduces approximately most of the empirical statistical results of natural river network. It is observed that the resulting network

Peter Borrmann, Heinrich Stamerjohanns, Eberhard Hilf, Philippe Jund

We use Monte Carlo simulations to investigate the thermodynamical behaviour of aggregates consisting of few superparamagnetic particles in a colloidal suspension. The potential energy surface of this classical two-level system with a stable and a metastable `ring' and `chain' configuration is tunable by an external magnetic field and temperature. We

Leon Balents, Jean-Philippe Bouchaud, Marc Mezard

We discuss the large scale effective potential for elastic objects (manifolds) in the presence of a random pinning potential, from the point of view of the Functional Renormalisation Group (FRG) and of the replica method. Both approaches suggest that the energy landscape at large scales is a succession of parabolic wells of random depth, matching on singular

Michael S. Turner, Evalyn I. Gates, Geza Gyuk

We discuss the implications of the recent upward revision of the LMC microlensing rate by the MACHO Collaboration. We conclude: (i) A good case for the existence of baryonic dark matter in the halo has been made; (ii) The case for the existence of cold dark matter is unaffected and still compelling; and (iii) The Galactic halo is still an excellent place to

P. E. Freeman, D. Q. Lamb, R. B. Wilson, M. S. Briggs

The cyclotron line in the spectrum of the accretion-powered pulsar Her X-1 offers an opportunity to assess the ability of the BATSE Spectroscopy Detectors (SDs) to detect lines like those seen in some GRBs. Preliminary analysis of an initial SD pulsar mode observation of Her X-1 indicated a cyclotron line at an energy of approximately 44 keV, rather than at

Bernhard Geiger, Peter Schneider

We propose a new technique to measure the time delay of radio-loud gravitational lens systems, which does not rely on the excessive use of interferometric observations. Instead, the method is based on single-dish flux density monitoring of the (unresolved) lens system's total lightcurve, combined with additional interferometric measurements of the flux d

Sabino Matarrese, David Terranova

The non--linear dynamics of self--gravitating irrotational dust is analyzed in a general relativistic framework, using synchronous and comoving coordinates. Writing the equations in terms of the metric tensor of the spatial sections orthogonal to the fluid flow allows an unambiguous expansion in inverse powers of the speed of light. The Newtonian and post--N

J. Siebert, W. Brinkmann, R. Morganti, C. N. Tadhunter

We present the soft X-ray (0.1--2.4 keV) properties of a complete sample of 88 southern radio sources derived from the Wall \& Peacock 2-Jy sample. It comprises 68 radio galaxies, 18 quasars and 2 BL Lac objects. Whereas both BL Lac objects and all but one quasar are detected in the {\it ROSAT} All-Sky Survey, the fraction of detected radio galaxies is only

Sumit R. Das, Samir D. Mathur

We examine the BPS and low energy non-BPS excitations of the D-string, in terms of open strings that travel on the D-string. We use this to study the energy thresholds for exciting a long D-string, for arbitrary winding number. We also compute the leading correction to the entropy from non-BPS states for a long D-string, and observe the relation of all these

Sourendu Gupta, K. Sridhar

We investigate the integrated cross section for forward $\jpsi$ production in proton-proton and pion-proton collisions at centre of mass energies upto 60 GeV. We find that colour-octet contributions to the cross section are crucially important, and their inclusion produces a very good description of the data. Since the values of non-perturbative matrix eleme

V. E. Adler

The Bäcklund transformation and its nonlinear superposition principle are presented for the Krichever-Novikov equation $u_t= u_{xxx} - {3/(2u_x)} (u^2_{xx} - r(u)) + cu_x, r^{(5)}=0$.

Kyoung J. Lee, Edward C. Cox, Raymond E. Goldstein

Quantitative experiments are described on spatio-temporal patterns of coherent chemical signaling activity in populations of {\it Dictyostelium discoideum} amoebae. We observe competition between spontaneously firing centers and rotating spiral waves that depends strongly on the overall cell density. At low densities, no complete spirals appear and chemotact

Eyal Yahel, Dror Orgad, Alexander Palevski, Hadas Shtrikman

We investigated the Integer Quantum Hall Effect (IQHE) using an inductive method. The following conclusions can be derived from our study: (i) when the Fermi energy is located between Landau levels the only extended states at the Fermi energy are located at the physical edges of the sample. (ii) the extended states located at the bulk of the sample below the

Martin White

We present a re-analysis of the cosmic confusion hypothesis, elucidating the degree to which ``confusion'' can be expected to hold in a class of flat, adiabatic models. This allows us to devise a simple and accurate fitting function for the height of the first peak in the radiation power spectrum in a wide range of inflationary inspired models. The r

Claudio Coriano', Lionel E. Gordon

We calculate $O(α_s)$ corrections to inclusive and isolated double prompt photon production, both for the unpolarized case, and for longitudinal polarization of the incoming hadrons. The calculation is performed using purely analytical techniques for the inclusive case, and a combination of analytical and Monte Carlo techniques to perform the phase space int

John N. Bahcall, E. Lisi, D. E. Alburger, L. De Braeckeleer

We present a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of $^8$B. We place special emphasis on determining the range of uncertainties permitted by existing laboratory data and theoretical ingredients (such as forbidden and radiative corrections). We review and compare the available experimental data on the $^8$B

M. Jimbo, H. Sakai, A. Ramani, B. Grammaticos

We show that the recently derived ($q$-) discrete form of the Painlevé VI equation can be related to the discrete P$_{\rm III}$, in particular if one uses the full freedom in the implementation of the singularity confinement criterion. This observation is used here in order to derive the bilinear forms and the Schlesinger transformations of both $q$-P$_{\rm

C. Ciofi degli Atti, S. Scopetta, A. Yu. Umnikov, L. P. Kaptari

Nuclear effects in the spin-dependent structure function $g_1$ of the deuteron are studied in the kinematics of future experiments at CEBAF, ($ν\leq 3~GeV, ~Q^2 \leq 2~GeV^2$). The magnitude of nuclear effects is found to be significantly larger than the one occurring in deep inelastic scattering ($ν\to \infty, ~Q^2\to \infty$). A possibility to measure the

P. Moller, J. R. Nix, K. -L. Kratz

We tabulate the ground-state odd-proton and odd-neutron spins and parities, proton and neutron pairing gaps, binding energy, one- and two-neutron separation energies, quantities related to beta-delayed one- and two-neutron emission probabilities, beta-decay energy release and half-life with respect to Gamow-Teller decay, one- and two-proton separation energi

Jian Ping Lu

Degenerate Hubbard models are studied using the Generalized-Gutzwiller-Approximation. It is found that the metal-insulator transition occurs at a finite correlation $U_c$ when the average number of electrons per lattice site is an integer. The critical $U_c$ depends sensitively on both the band degeneracy $N$ and the filling $x$. A derivation is presented fo

Yusuke Kato, Yoshio Kuramoto

We construct thermodynamics of the one-dimensional supersymmetric {\it t-J} model with the $ 1/\sin^2$ interaction and hopping. The thermodynamics is described exactly in terms of free spinons and holons obeying Haldane's fractional exclusion statistics at all temperatures. Moreover, at low temperatures the semionic spinons and holons decouple resulting

János Kollár

These are the revised notes of my lectures at the 1995 Santa Cruz summer institute. Changes from the Jan.26,1996 version: Major: 7.1--2; Medium: 3.7, 3.11, 5.3.3, 7.9.2, 9.8.

E. Bergshoeff, M. de Roo, M. B. Green, G. Papadopoulos

We present a version of ten-dimensional IIA supergravity containing a 9-form potential for which the field equations are equivalent to those of the standard, massless, IIA theory for vanishing 10-form field strength, $F_{10}$, and to those of the `massive' IIA theory for non-vanishing $F_{10}$. We present a multi 8-brane solution of these equations that

M. J. Fullana, J. V. Arnau, D. Sáez

The Tolman-Bondi solution of the Einstein equations is used in order to model the time evolution of the void observed in Boötes. The present density contrast of the central region ($\sim -0.75$) and its radius ($\sim 30h^{-1} \ Mpc$) are fixed, while the density parameter of the Universe, the amplitude of the density contrast inside the void wall, the width

Wim Beenakker, Geert Jan van Oldenborgh, Jiri Hoogland, Ronald Kleiss

We consider the problem of a proper definition of the mass of a heavy unstable boson. It is shown how various definitions are related by the renormalization-scheme independence of the full resummed amplitude. This is made explicit for the $W$ boson in the large $N_f$ limit, where we find an upper bound on the peak position of the lineshape and on the mass, p

Meral Aydin, Yigit Gunduc, Tarik Celik

The two-dimensional Potts Model with 2 to 10 states is studied using a cluster algorithm to calculate fluctuations in cluster size as well as commonly used quantities like equilibrium averages and the histograms for energy and the order parameter. Results provide information about the variation of cluster sizes depending on the temperature and the number of

A. Mikovic, B. Sazdovic

We discuss a canonical formalism method for constructing actions describing propagation of W-strings on curved backgrounds. The method is based on the construction of a representation of the W-algebra in terms of currents made from the string coordinates and the canonically conjugate momenta. We construct such a representation for a W_3-string propagating in

N. Aizawa, H. -T. Sato

We discuss a spectrum generating algebra in the supersymmetric quantum mechanical system which is defined as a series of solutions to a specific differential equation. All Hamiltonians have equally spaced eigenvalues, and we realize both positive and negative mode generators of a subalgebra of $W_{1+\infty}$ without use of negative power of raising/lowering

Michiyasu Nagasawa

The amount of baryon asymmetry generated by the electroweak strings at a rough estimate is smaller than that generated by the bubble expansion since the collapsing strings cannot cover the whole volume of the universe. However, the interaction cross section of the strings with particles can be larger than the geometrical area of the order of the string thick

Matilde Marcolli

This paper presents the construction of the Seiberg-Witten-Floer homology of three-manifolds with non-trivial rational homology, and some properties of the invariant of three-manifolds obtained by computing the Euler characteristic. This new version corrects a mistake and some misprints that appear in the published version (Internat. J. Math., Vol.7, N.5 (19

C. H. Lineweaver, L. Tenorio, G. F. Smoot, P. Keegstra

The largest anisotropy in the cosmic microwave background (CMB) is the $\approx 3$ mK dipole assumed to be due to our velocity with respect to the CMB. Using the four year data set from all six channels of the COBE Differential Microwave Radiometers (DMR), we obtain a best-fit dipole amplitude $3.358 \pm 0.001 \pm 0.023$ mK in the direction $(l,b)=(264°.31 \

M. de Sousa Vieira, A. J. Lichtenberg

We generalize a method of control of chaos which uses delayed feedback at the period of an unstable orbit to stabilize that orbit. The generalization consists of substituting some portion of the nonlinear dynamical system with a delayed dynamics, rather than using a linear delay function for control. A further generalization, in which the control function re

Wen-Xiu Ma, Benno Fuchssteiner

The bi-Hamiltonian structure is established for the perturbation equations of KdV hierarchy and thus the perturbation equations themselves provide also examples among typical soliton equations. Besides, a more general bi-Hamiltonian integrable hierarchy is proposed and a remark is given for a generalization of the resulting perturbation equations to $1+2$ di

Xiao-Biao Lin

Assuming that a formal approximation of multiple waves has been obtained by matched asymptotic methods, we derive a {\em Spatial Shadowing lemma} to construct exact solutions near the formal approximation. In Part I, we consider a general singularly perturbed parabolic system. $$ εu_t + (-ε^2)^m D^{2m}_x u = f(u,εu_x,\cdots,(εD_x)^{2m-1} u,x,ε). $$ We show t

J. L. Friar, G. L. Payne

An assessment is made of the dominant features contributing to the triton potential energy, with the objective of understanding qualitatively their origins and sensitivities. Relativistic effects, short-range repulsion, and OPEP dominance are discussed. A determination of the importance of various regions of nucleon-nucleon separation is made numerically.

Bao-An Li, Che Ming Ko

Using the relativistic transport model (ART), we predict the energy dependence of the stopping power, maximum baryon and energy densities, the population of resonance matter as well as the strength of the transverse and radial flow for central Au+Au reactions at beam momentum from 2 to 12 GeV/c available at Brookhaven's AGS. The maximum baryon and energy

Manual Alfaro, Francisco Marcellán

Let the Sobolev-type inner product <f,g> = \int fg d mu_0+ int f&#39; g&#39; d mu_1 with mu_0 = w + M delta_c, mu_1= N delta_c where w is the Jacobi weight, c is either 1 or -1 and M, N >= 0. We obtain estimates and asymptotic properties on [-1,1] for the polynomials orthonormal with respect to <.,.> and their kernels. We also compare these polynomials with

Serguei Treil

The main result of the paper is that a system of invariant subspaces of a (completely non-unitary) Hilbert space contraction $T$ with finite defects (rank$(I-T^*T)<\infty$, rank$(I-TT^*)<\infty$) is an unconditional basis (Riesz basis) if and only if it is uniformly minimal. Results of such type are quite well known: for a system of eigenspaces of a contract

Valentin Ferenczi

A Banach space $X$ is said to be Q.H.I. if eve\-ry infinite dimensional quo\-tient spa\-ce of $X$ is H.I.: that is, a space is Q.H.I. if the H.I. property is not only stable passing to subspaces, but also passing to quotients and to the dual. We show that Gowers-Maurey&#39;s space is Q.H.I.; then we provide an example of a reflexive H.I. space ${\cal X}$ who

T. Banks

This is the written version of a talk given at the Santa Barbara Workshop on Supersymmetry in December of 1995. It summarizes a collection of results on superstring cosmology obtained by the author and various collaborators, and contains some speculations about the resolution of the cosmological constant and vacuum selection problems in string theory.

M. Arik, G. Unel

We propose an alternative to Dirac quantization for a quadratic constrained system. We show that this solves the Jacobi identity violation problem occuring in the Dirac quantization case and yields a well defined Fock space. By requiring the uniqueness of the ground state, we show that for non-constrained systems this approach gives the same results as Dirac

Conor Houghton, Paul Sutcliffe

By imposing certain combined inversion and rotation symmetries on the rational maps for SU(2) BPS monopoles we construct geodesics in the monopole moduli space. In the moduli space approximation these geodesics describe a novel kind of monopole scattering. During these scattering processes axial symmetry is instantaneously attained and, in some, monopoles wi

Conor Houghton, Paul Sutcliffe

It is shown that there exists a charge five monopole with octahedral symmetry and a charge seven monopole with icosahedral symmetry. A numerical implementation of the ADHMN construction is used to calculate the energy density of these monopoles and surfaces of constant energy density are displayed. The charge five and charge seven monopoles look like an octa

Conor Houghton, Paul Sutcliffe

Using a numerical implementation of the ADHMN construction, we compute the fields and energy densities of a charge three monopole with tetrahedral symmetry and a charge four monopole with octahedral symmetry. We then construct a one parameter family of spectral curves and Nahm data which represent charge four monopoles with tetrahedral symmetry, which includ