December 1995 arXiv papers — page 6

Alexander Vilenkin

In models where the constants of Nature can take more than one set of values, the cosmological wave function $ψ$ describes an ensemble of universes with different values of the constants. The probability distribution for the constants can be determined with the aid of the `principle of mediocrity' which asserts that we are a `typical' civilization in

M. J. W. Dodgson

We consider the problem of finding the ground state of a model type-II superconductor on the two-dimensional surface of a sphere, penetrated by $N$ vortices. Numerical work shows the ground states to consist of a triangular network of the vortices with twelve five-coordinated centres. Values of $N$ are found with particularly low energy ground states, due to

Orio Tomagnini, Furio Ercolessi, Simonetta Iarlori, Francesco D. Di Tolla

The contrasting melting behavior of different surface orientations in metals can be explained in terms of a repulsive or attractive effective interaction between the solid-liquid and the liquid-vapor interface. We show how a crucial part of this interaction originates from the layering effects near the liquid metal surface. Its sign depends on the relative t

T. Blum, M. A. Moore

We investigate the nonlocal conductivity calculated from the time-dependent Ginzburg-Landau equation. When the fluctuations of the vector potential are negligible, the high-temperature (Gaussian) and low-temperature (flux-flow) forms of the uniform conductivity withan an ab plane (sigma_yy) are essentially identical. We find to what extent the nonlocal condu

Tohru Koma, Bruno Nachtergaele

We prove that the spectral gap of the spin-1/2 ferromagnetic XXZ chain with Hamiltonian $H=-\sum_x S^{(1)}_xS^{(1)}_{x+1}+S^{(2)}_xS^{(2)}_{x+1} +ΔS^{(3)}_xS^{(3)}_{x+1}$, is given by $Δ-1$ for all $Δ\geq 1$. This is the gap in the spectrum of the infinite chain in any of its ground states, the translation invariant ones as well as the kink ground states, wh

Marcus Rickert, Kai Nagel, Michael Schreckenberg, Andreas Latour

We examine a simple two lane cellular automaton based upon the single lane CA introduced by Nagel and Schreckenberg. We point out important parameters defining the shape of the fundamental diagram. Moreover we investigate the importance of stochastic elements with respect to real life traffic.

A. G. Rojo

A proof is presented for the absence of gap for spin $1/2$ ladders with an odd number of legs, in the infinite leg length limit. This result is relevant to the current discussion of coupled one--dimensional spin systems, a physical realization of which are vanadyl pyrophosphate, (VO)$_2$P$_2$O$_7$, and stoichiometric Sr$_{n-1}$ Cu$_{n+1}$ O$_{2n}$ (with $n=3

V. M. H. Ruutu, V. B. Eltsov, A. J. Gill, T. W. B. Kibble

We report the observation of vortex formation upon the absorption of a thermal neutron in a rotating container of superfluid $^3$He-B. The nuclear reaction n + $^3$He = p + $^3$H + 0.76MeV heats a cigar shaped region of the superfluid into the normal phase. The subsequent cooling of this region back through the superfluid transition results in the nucleation

G. M. Williger, C. Hazard, J. A. Baldwin, R. G. McMahon

We have made a statistically complete, unbiased survey of C IV systems toward a region of high QSO density near the South Galactic Pole using 25 lines of sight spanning $1.5<z<2.8$. Such a survey makes an excellent probe of large-scale structure at early epochs. We find evidence for structure on the $15-35h^{-1}$ proper Mpc scale ($H_0 \equiv 100$ km $s^{-1}

A. G. Weiss, S. Gottloeber, T. Buchert

We report on the performance of Lagrangian perturbation theory up to the second order for the standard cold dark matter (SCDM) and broken scale invariance (BSI) scenarios. We normalize both models to the COBE data, the BSI model serves as an example of models which fit the small-scale power of galaxy surveys. We optimize Lagrangian perturbation solutions by

M. Kerscher, J. Schmalzing, T. Buchert

We discuss the application of Minkowski functionals to galaxy catalogues with emphasis on the boundary corrections and point out the relevance for other statistical methods. The analysis of a cubic subsample of the CfA--1 data serves as an example.

H. Ebeling, S. W. Allen, C. S. Crawford, A. C. Edge

We present the X-ray luminosity function (XLF) of the ROSAT Brightest Cluster Sample (BCS), an X-ray selected, flux limited sample of 172 clusters of galaxies at $z\leq 0.3$ compiled from ROSAT All-Sky Survey data. While the bulk of the BCS consists of Abell clusters, the sample also contains Zwicky clusters and purely X-ray selected systems. The BCS-XLF rep

R. Oestensen, S. Refsdal, R. Stabell, J. Teuber

We report results from five years of monitoring of the Einstein Cross (Q 2237+0305) with the Nordic Optical Telescope. The photometry, mainly in the R and I bands, has been performed by a PSF fitting and `cleaning&#39; procedure, in which the four image components as well as the lens galaxy and its nucleus are iteratively removed. The resulting lightcurves e

Hyung Mok Lee, Hyesung Kang, Dongsu Ryu

A star around a massive black hole can be disrupted tidally by the gravity of the black hole. Then, its debris may form a precessing stream which may even collide with itself. In order to understand the dynamical effects of the stream-stream collision on the eventual accretion of the stellar debris onto the black hole, we have studied how gas flow behaves wh

P. L. Natti, A. F. R. de T. Piza

A time-dependent projection technique is used to treat the initial-value problem for self-interacting fermionic fields. On the basis of the general dynamics of the fields, we derive formal equations of kinetic type for the set of one-body dynamical variables. A nonperturbative mean-field expansion can be written for these equations. We treat this expansion i

Yuri Smirnov, Alexander Turbiner

The connection between polynomial solutions of finite-difference equations and finite-dimensional representations of the $sl_2$-algebra is established (the talk given at the Wigner Symposium, Guadalajara, Mexico, August 1995, to be published in the Proceedings)

Valeri V. Dolotin

Here we develop a technique of computing the invariants of $n-$ary forms and systems of forms using the discriminants of corresponding multilinear forms built of their partial derivatives, which should be cosidered as analogues of classical discriminants and resultants for binary forms.

Thomas G. Philbin

The diagonal metric tensor whose components are functions of one spatial coordinate is considered. Einstein&#39;s field equations for a perfect-fluid source are reduced to quadratures once a generating function, equal to the product of two of the metric components, is chosen. The solutions are either static fluid cylinders or walls depending on whether or no

Luis A. Cabral, Victor O. Rivelles

This paper has been withdraw by the authors. An enlarged and complete analysis of the constraints is presented in hep-th/9910163. It includes also relativistic particles and strings. The non-relativistic particle quantization has been reanalyzed.

E. H. Lieb, L. E. Thomas

The polaron has been of interest in condensed matter theory and field theory for about half a century, especially the limit of large coupling constant. It was not until 1983, however, that a proof of the asymptotic formula for the ground state energy was finally given by using difficult arguments involving the large deviation theory of path integrals. Here w

G. Feverati, E. Quattrini, F. Ravanini

It is known that any minimal model M_p receives along its phi_31 irrelevant direction *two* massless integrable flows: one from M_{p+1} perturbed by phi_{13}, the other from Z_{p-1} parafermionic model perturbed by its generating parafermion field. By comparing Thermodynamic Bethe Ansatz data and ``predictions&#39;&#39; of infrared Conformal Perturbation The

Dirk Schlingemann

There are several two dimensional quantum field theory models which are equipped with different vacuum states. For example the Sine-Gordon- and the $ϕ^4_2$-model. It is known that in these models there are also states, called soliton- or kink-states, which interpolate different vacua. We consider the following question: Which are the properties a pair of vac

Subhashis Nag

We first give an exposition of how the Polyakov path integral for the bosonic string produces a natural mapping class group invariant measure, $d(Poly)$, on the Teichmüller space of Riemann surfaces of each fixed genus. The description of $d(Poly)$ via the Mumford isomorphisms for determinant bundles over Teichmüller space is also explained. We then report o

R. S. Bhalla, A. K. Kapoor, P. K. Panigrahi

It is well known in classical mechanics that, the frequencies of a periodic system can be obtained rather easily through the action variable, without completely solving the equation of motion. The equivalent quantum action variable appearing in the quantum Hamilton-Jacobi formalism, can, analogously provide the energy eigenvalues of a bound state problem, wi

J. Kamoshita, Y. Okada, M. Tanaka

We examine whether the parameters in the Higgs sector of the minimal supersymmetric standard model can be determined by detailed study of production cross section and decay branching ratios of the Higgs particle. Assuming that the lightest CP-even Higgs boson ($h$) is observed at a future $e^+ e^-$ linear collider with $\sqrt{s}=300\sim500$GeV, we show that

Emilio N. M. Cirillo, Sebastiano Stramaglia

We propose a spin model with a new kind of ferromagnetic interaction, which may be called {\it ferromagnetic coupling with threshold}. In this model the contribute of a given spin to the total energy has only two possible values and depends on the number of parallel spins among its nearest and next to the nearest neighbors. By mapping the model onto the Isin

R. Akhoury, I. Z. Rothstein

In this paper we discuss the theoretical difficulties in extracting $V_{ub}$ using the data from inclusive B decays. Specifically, we address the issue of the end point singularities. We perform the resummation of both the leading and next to leading end point logs and include the leading corrections to the hard scattering amplitude. We find that the resumma

Hao Li, Chao Tang, Ned Wingreen

In a statistical approach to protein structure analysis, Miyazawa and Jernigan (MJ) derived a $20\times 20$ matrix of inter-residue contact energies between different types of amino acids. Using the method of eigenvalue decomposition, we find that the MJ matrix can be accurately reconstructed from its first two principal component vectors as $M_{ij}=C_0+C_1(

E. A. Jagla, C. A. Balseiro

The nature of the resistive transition for a current applied parallel to the magnetic field in high-Tc materials is investigated by numerical simulation on the three dimensional Josephson junction array model. It is shown by using finite size scaling that for samples with disorder the critical temperature Tp for the c axis resistivity corresponds to a percol

R. S. Bhalla, A. K. Kapoor, P. K. Panigrahi

Exactness of the lowest order supersymmetric WKB (SWKB) quantization condition $\int^{x_2}_{x_1} \sqrt{E-ω^2(x)} dx = n \hbar π$, for certain potentials, is examined, using complex integration technique. Comparison of the above scheme with a similar, but {\it exact} quantization condition, $\oint_c p(x,E) dx = 2πn \hbar$, originating from the quantum Hamilto

Satoshi Chiba, Mark B. Chadwick, Koji Niita, Toshiki Maruyama

The preequilibrium (nucleon-in, nucleon-out) angular distributions of $^{27}$Al, $^{58}$Ni and $^{90}$Zr have been analyzed in the energy region from 90 to 200 MeV in terms of the Quantum Moleculear Dynamics (QMD) theory. First, we show that the present approach can reproduce the measured (p,xp&#39;) and (p,xn) angular distributions leading to continuous fin

T. C. Ferree, D. S. Koltun

We estimate the contribution of inelastic nucleon excitations to the $(e,e^\prime)$ inclusive cross section in the CEBAF kinematic range. Calculations are based upon parameterizations of the nucleon structure functions measured at SLAC. Nuclear binding effects are included in a vector-scalar field theory, and are assumed have a minimal effect on the nucleon

Carroll Guillory, Kin Y. Li

Let $Ω$ and $Ω_{\fin}$ be the sets of all interpolating Blaschke products of type $G$ and of finite type $G$, respectively. Let $E$ and $E_{\fin}$ be the Douglas algebras generated by $H^\infty$ together with the complex conjugates of elements of $Ω$ and $Ω_{\fin}$, respectively. We show that the set of all invertible inner functions in $E$ is the set of all

Gilles Pisier

Let $u_1,\ldots,u_n$ be unitary operators on a Hilbert space $H$. We study the norm $$\left\|\sum^{i=n}_{i=1} u_i \otimes \bar u_i\right\|\leqno (1)$$ of the operator $\sum u_i \otimes \bar u_i$ acting on the Hilbertian tensor product $H\otimes_2 \overline H$. The main result of this note is Theorem 1. For any $n$-tuple $u_1,\ldots, u_n$ of unitary operators

Vipul Periwal

Halpern and Huang recently showed that there are relevant directions in the space of interactions at the Gaussian fixed point. I show that their result can be derived from Polchinski&#39;s form of the Wilson renormalization group. The derivation shows that the existence of these directions is independent of the cutoff function used.

Oren Bergman, Charles B. Thorn

We construct a 1+1 dimensional superstring-bit model for D=3 Type IIB superstring. This low dimension model escapes the problems encountered in higher dimension models: (1) It possesses full Galilean supersymmetry; (2) For noninteracting polymers of bits, the exactly soluble linear superpotential describing bit interactions is in a large universality class o

F. Antonuccio, S. Dalley

We propose an extension of &#39;t Hooft&#39;s large-$N_c$ light-front QCD in two dimensions to include helicity and physical gluon degrees of freedom, modelled on a classical dimensional reduction of four dimensional QCD. A non-perturbative renormalisation of the infinite set of coupled integral equations describing boundstates is performed. These equations

L. A. Ferreira, J-L. Gervais, J. Sanchez Guillen, M. V. Saveliev

We investigate higher grading integrable generalizations of the affine Toda systems. The extra fields, associated to non zero grade generators, obey field equations of the Dirac type and are regarded as matter fields. The models possess soliton configurations, which can be interpreted as particles of the theory, on the same footing as those associated to fun

Dmitrij V. Volkov

Two approaches concerning the connection of the fermionic kappa -- symmetry with the superstring world -- sheet superdiffeomorphism transformations are discussed. The first approach is based on the twistor -- like formulation of the superstring action and the second one on a reformulation of the superstring and super~-~p~-~brane actions according to the Gene

Aleksey Yu. Nurmagambetov

In this review I discuss some recent results concerning D=4 doubly supersymmetric membranes within the framework of geometrical approach obtained in the collaboration with Igor Bandos, Dmitrij Sorokin and Dmitrij Volkov.

A. A. Slavnov

Representation of a $D$-dimensional fermion determinant as a path integral of exponent of a $(D+1)$-dimensional Hermitean bosonic action is constructed.

M. Awada, F. Mansouri

We obtain an explicit expression for the supersymmetric Wilson loop in terms of chiral superfields and supercurrents in superspace. The result turns out to be different from what one would expect from the simple replacement of Lie algebra valued connection in the exponent with the corresponding super-Lie algebraic one. Genralizing the super particle coupling

E. Gotsman, E. M. Levin, U. Maor

In this letter we show that the behaviour of $F_{2}$, at very small $x_B$, agrees with the behaviour expected from the BFKL evolution equation, when screening corrections are included. We obtain a description which is consistent with the data, however, we require the screening corrections to be relatively large (about a quarter of the total DIS cross section

Robert J. Oakes

The cross sections for the production of $B_s$ and $B_s^*$ mesons through the fragmentation process in $\bar{p}p$ collisions were calculated. The input parameters were determined from the measured $B_s$ and $B_s^*$ production rates in $e^+e^-$ annihilation. The transverse momentum distributions $dσ/dp_{T}$ are given for $\sqrt{s}=1.8$ TeV, the Fermilab Tevat

P. Q. Hung, Marc Sher

If the Higgs boson has a mass below 130 GeV, then the standard model vacuum is unstable; if it has a mass below 90 GeV (i.e. within reach of LEP within the next two years), then the instability will occur at a scale between 800 GeV and 10 TeV. We show that precise determinations of the Higgs and top quark masses as well as more detailed effective potentialca

A. Djouadi, W. Kilian, P. Ohmann

We summarize the work done by the European working group on Higgs Particles for the Workshop ``Physics with e$^+$e$^-$ Linear Colliders&#34;, Annecy--Gran Sasso--Hamburg, Feb.--Sept. 1995. The main focus will be on the physics possibilities at a second phase e$^+$e$^-$ linear collider with a center of mass energy of $\sim 1.5$ TeV.

A. Djouadi

We summarize the potential of high--energy $\ee$ linear colliders for discovering, and in case of discovery, for studying the signals of extended gauge models. We will mainly focus on the virtual signals of new neutral gauge bosons and on the production of new heavy leptons. [Invited talk given at the Workshop on Physics and Experiments with Linear Colliders

R. Engel, A. Schiller, V. G. Serbo

We consider the radiation of particles of one bunch in the collective field of the oncoming bunch, called coherent bremsstrahlung (CBS). The main characteristics of CBS for LHC (in the Pb-Pb mode) and for RHIC are calculated. At LHC about $3.9 10^8 dE_γ/E_γ$ photons per second are expected for photon energies $E_γ\stackrel{<} {\sim} E_c= 93 $ eV. It seems th

G. Camici, M. Ciafaloni

We investigate small$-x$ resummation effects in QCD coefficient functions for $Z_0g$ and $Wg$ fusion processes, and we compare them with the known ones of $γg$ type. We find a strong process dependence, that we argue to be due to the possible presence of collinear singularities for either small or large $\k$ of the exchanged gluon. For top quark production,

Paul Singer

A review is presented of the weak radiative decays of baryons.It includes an anlysis of the possible contributions of electromagnetic penguins to these decays,a survey of the difficulties still encountered in the sector of hyperon decays and a short account on some new developments on this topic. The theoretical treatments on charm and beauty baryon decays a

Takayuki Shigetani, Katsuhiko Suzuki, Hiroshi Toki

We study off-shell effects of the pion cloud on the sea quark distribution in the nucleon. The structure function of the off-mass-shell pion is obtained within the Nambu and Jona-Lasinio model, where the shape of the distribution function depends on the pion momentum. By using the momentum dependent pion structure function, the SU(2) flavor asymmetry in the

Tetsuya Shiromizu

In a weakly first order phase transition the typical scale of a subcritical bubble calculated in our previous papers turned out to be too small. At this scale quantum fluctuations may dominate and our previous classical result may be altered. So we examine the critical size of a subcritical bubble where quantum-to-classical transition occurs through quantum

Dietrich Lehner

A total and differential cross-section calculation for the Electroweak Standard Model reaction $e^+ e^- \rightarrow (Z^0 Z^0) \rightarrow f_1\bar{f_1}f_2\bar{f_2}(γ)$\ including the effects of the finite $Z^0$\ width and, for the first time, all QED initial state radiative corrections (ISR) is presented. A semi-analytical technique is used: All angular phase

M. Guertler, E. -M. Ilgenfritz, J. Kripfganz, H. Perlt

We study the electroweak phase transition by lattice simulations of an effective 3-dimensional theory, for a Higgs mass of about $70$ GeV. Exploiting a variant of the equal weight criterion of phase equilibrium, we obtain transition temperature, latent heat and surface tension and compare with $M_H \approx 35$ GeV. For the symmetric phase, bound state masses

E. M. Monte, M. D. Maia

The fundamental theorem of submanifolds is adapted to space-times. It is shown that the integrability conditions for the existence of submanifolds of a pseudo-Euclidean space contain the Einstein and Yang-Mills equations.

V. Ovsienko

We consider formal deformations of the Poisson algebra of functions (with singularities) on $T^*M$ which are Laurent polynomials of fibers. Tn the case: $\dim M=1$ ($M=S^1, {\bf R}$), there exists a non-trivial $\star$-product on this algebra non-equivalent to the standard Moyal product.

Mark Srednicki

We show that the results of Prigodin et al can be reproduced and simplified by making use of Berry&#39;s conjecture that the energy eigenfunctions in a quantized chaotic system are gaussian random variables.

M. W. Wu, N. J. M. Horing, H. L. Cui

We carry out a calculation of the phonon-drag contribution $S_g$ to the thermoelectric power of bulk semiconductors and quantum well structures for the first time using the balance equation transport theory extended to the weakly nonuniform systems. Introducing wavevector and phonon-mode dependent relaxation times due to phonon-phonon interactions, the formu

Jeong-Man Park, T. C. Lubensky

A disclination in a hexatic membrane favors the development of Gaussian curvature localized near its core. The resulting global structure of the membrane has mean curvature, which is disfavored by curvature energy. Thus a membrane with an isolated disclination undergoes a buckling transition from a flat to a buckled state as the ratio $κ/K_{A}$ of the bendin

Howard L. Richards, Mark A. Novotny, Per Arne Rikvold

An important aspect of real ferromagnetic particles is the demagnetizing field resulting from magnetostatic dipole-dipole interaction, which causes large particles to break up into domains. Sufficiently small particles, however, remain single-domain in equilibrium. This makes such small particles of particular interest as materials for high-density magnetic

Joachim Ankerhold, Hermann Grabert

The dynamics near the top of a potential barrier is studied in the temperature region where quantum effects become important. The time evolution of the density matrix of a system that deviates initially from equilibrium in the vicinity of the barrier top but is in local equilibrium away from the barrier top is determined. Explicit results are given for a ran

J. F. Bell, F. Camilo, T. Damour

Gravity being a long-range force, one might {\it a priori} expect the Universe&#39;s global matter distribution to select a preferred rest frame for local gravitational physics. The phenomenology of preferred-frame effects, in the strong-gravitational field context of binary pulsars, is described by two parameters $\hatα_1$ and $\hatα_2$. These parameters va

Chris Mihos, Lars Hernquist

Using numerical simulation, we study the development of gaseous inflows and triggering of starburst activity in mergers of comparable-mass disk galaxies. In all encounters studied, the galaxies experience strong gaseous inflows and moderate to intense starburst activity. We find that galaxy structure plays a dominant role in regulating activity. The gaseous

I. Semeniuk, A. Olech, M. Nalezyty

We report on CCD photometry of Nova V1500 Cygni obtained in July 1995 to show that twenty years after outburst, being of about 18~mag, the star can still be observed with small telescopes. The 0.1396 day period continues to be stable.

W. Steffen, A. J. Holloway, A. Pedlar, D. J. Axon

The emission lines in the active galaxy IRAS 0421+0400 show a dramatic (~ 900 km/s) increase in the velocity spread at the position of radio hotspots which are located at the beginning of extended radio lobes. We study a model which explains this phenomenon as the result of a jet emerging through the boundary between the interstellar and intergalactic media.

Monica Tosi

The {\it best} chemical evolution models for the galactic disk computed by different groups with different assumptions are compared with each other and with the observational constraints. Differences and similarities between the models are discussed, emphasizing the importance of testing not only the solar neighbourhood but the whole disk. The history of the

Xue-Bing Wu, Qi-Bin Li

The local stability of accretion disks with advection is studied together with the considerations of radial viscous force and thermal diffusion. For a geometrically thin, radiative cooling dominated disk, the thermal diffusion has nearly no effects on the thermal and viscous modes. The including of thermal diffusion, however, tends to stabilize the acoustic

Gordon Squires, Nick Kaiser

Weak lensing observations measure the shear field and hence the gradient of the dimensionless surface density $κ$. We present several new algorithms to recover $κ$ {}from shear estimates on a finite region and compare how they perform with realistically noisy data. The reconstruction methods studied here are divided into 2 classes: direct reconstruction and

Heino Falcke

In this paper I review the results of our ongoing project to investigate the coupling between accretion disk and radio jet in galactic nuclei and stellar mass black holes. We find a good correlation between the UV bump luminosity and the radio luminosities of AGN, which improves upon the usual [OIII]/radio correlations. Taking mass and energy conservation in

Heino Falcke, Peter L. Biermann

We present a simple argument that the missing x-ray flux from the Galactic Center source Sgr~A* ist not evidence {\it against} -- as claimed by Goldwurm et al. 1994 -- but rather indirect evidence {\it for} the presence of a supermassive black hole. The radio spectrum provides a strict {\it lower} limit for the size of Sgr~A* ($R>3\cdot 10^{11}$cm). A more c

Takesi Kawasaki

The notion of Macaulayfication, which is analogous of the desingularization, was introduced by Faltings in 1978 and he construct a Macaulayfication of quasi-projective scheme whose non-Cohen-Macaulay locus is of dimension 0 or 1 by a characteristic free method. In this paper, we gave a Macaulayfication of a quasi-projective scheme whose non-Cohen-Macaulay lo

N. Arkani-Hamed, H-C Cheng, L. J Hall

Supersymmetric theories involving a spontaneously broken flavor symmetry can solve the flavor-changing problem while having quark and lepton masses derived from both $F$ and $D$ terms. As an example, a theory of leptons is constructed in which holomorphy constrains the electron to be massless at tree level. The electron flavor symmetries are broken by D term

J. A. Teschner

The chiral vertex operators for the minimal models are constructed and used to define a fusion product of representations. The existence of commutativity and associativity operations is proved. The matrix elements of the associativity operations are shown to be given in terms of the 6-j symbols of the weak quasitriangular quasi-Hopf algebra obtained by trunc

Tanmoy Bhattacharya, Rajan Gupta, Gregory Kilcup, Stephen Sharpe

We present results of a high statistics study of the quenched spectrum using Wilson fermions at $β=6.0$ on $32^3 \times 64$ lattices. We calculate the masses of mesons and baryons composed of both degenerate and non-degenerate quarks. Using non-degenerate quark combinations allows us to study baryon mass splittings in detail. We find significant deviations f

Mark Dickinson, Arjun Dey, Hyron Spinrad

We report ground based and HST observations of the z=1.206 radio galaxy 3C 324, a prototypical example of the radio-optical ``alignment effect.&#39;&#39; While infrared images shows a simple, round object reminiscent of a giant elliptical galaxy, the HST images reveal a spectacular, linear chain of UV-bright subcomponents closely aligned with the radio axis.

Jonathan L. Rosner

It has now become possible to observe appreciable numbers of hadronically produced lepton pairs in mass ranges where the contributions of the photon and $Z^0$ are comparable. Consequently, in the reaction $p \bar p \to \ell^- \ell^+ + \ldots$, substantial forward-backward asymmetries can be seen. These asymmetries provide a test of the electroweak theory in

B. Holdom

Four-fermion operators may have large anomalous scaling and become relevant operators in some strongly interacting gauge theories. We present a detailed model which illustrates some of the implications of such operators for the generation of quark and lepton masses. Such operators would originate at high scales where quarks and leptons experience a new stron

P. Talavera, Ll. Ametller, J. Bijnens, A. Bramon

The $γγ\to π^0 π^0 π^0$ and $γγ\to π^+ π^- π^0$ amplitudes are discussed in the general context of Chiral Perturbation Theory (ChPT) to $O(p^6)$. Chiral loops are found to play a major role. This makes these processes a good test of ChPT, mainly in its anomalous sector. We correct earlier numerical results at tree level and determine the one-loop results as

Srinandan Dasmahapatra

We establish a weight-preserving bijection between the index sets of the spectral data of row-to-row and corner transfer matrices for $U_q\widehat{sl(n)}$ restricted interaction round a face (IRF) models. The evaluation of momenta by adding Takahashi integers in the spin chain language is shown to directly correspond to the computation of the energy of a pat

Roland Fehrenbacher

We consider the effect of non-magnetic impurities in a $d_{x^2 - y^2}$ superconductor with $\ef$ close to a van Hove singularity. It is shown that the non-trivial density of states (DOS) allows for resonant scattering already at intermediate potential strengths $|u| \approx 1-2$eV. The residual DOS at $\ef$, and the \tc suppression rate are found to strongly

R. G. Carlberg, H. K. C. Yee, E. Ellingson

The systematic errors in the virial mass-to-light ratio, M_v/L, of galaxy clusters as an estimator of the field M/L value are assessed. We overlay 14 clusters in redshift space to create an ensemble cluster which averages over substructure and asymmetries. The combined sample, including background, contains about 1150 galaxies, extending to a projected radiu

L. Langer, V. Bayot, E. Grivei, J. -P. Issi

We report on electrical resistance measurements of an individual carbon nanotube down to a temperature T=20 mK. The conductance exhibits a ln T dependence and saturates at low temperature. A magnetic field applied perpendicular to the tube axis, increases the conductance and produces aperiodic fluctuations. The data find a global and coherent interpretation

B. M. Pimentel, R. G. Teixeira

Recently the Hamilton-Jacobi formulation for first order constrained systems has been developed. In such formalism the equations of motion are written as total differential equations in many variables. We generalize the Hamilton-Jacobi formulation for singular systems with second order Lagrangians and apply this new formulation to Podolsky electrodynamics, c

A. L. Barabanov

We consider a simplified model for resonant neutron-nucleus interaction with coupled channels. An analytical solution is given for two coupled channels and arbitrary neutron orbital momentum. A case of a week channel coupling, corresponding to narrow Breit-Wigner resonance, is analyzed in details. As far as the total width of a resonance coincides with the n

M. G. Ryskin, Yu. M. Shabelski, A. G. Shuvaev

We consider the light quark electroproduction cross section and show that the contribution coming from the infrared ($q_T<300\, MeV$) region is not negligible. It changes the $F_2(x,Q^2)/xG(x,Q^2)$ ratio by 20-30\% (or even more) for small $x$ and $Q^2\sim 4\, GeV^2$.

L. Gamberg, H. Weigel, U. Zückert, H. Reinhardt

The Nambu--Jona-Lasinio model (NJL) is extended to incorporate heavy quark spin-symmetry. In this model baryons containing one heavy quark are analyzed as bound-states of light baryons, represented as chiral solitons, and mesons containing one heavy quark. From related studies in Skyrme type models, the ground-state heavy baryon is known to arise for the hea

J. Kierfeld, T. Nattermann, T. Hwa

The stability of a vortex glass phase with quasi-long-range positional order is examined for a disordered layered superconductor. The role of topological defects is investigated using a detailed scaling argument, supplemented by a variational calculation. The results indicate that topological order is preserved for a {\em wide range} of parameters in the vor

Yigal Shamir

Several years ago it was conjectured in the so-called Roma Approach, that gauge fixing is an essential ingredient in the lattice formulation of chiral gauge theories. In this paper we discuss in detail how the gauge-fixing approach may be realized. As in the usual (gauge invariant) lattice formulation, the continuum limit corresponds to a gaussian fixed poin

T. Stelzer, S. Willenbrock

We propose techniques to observe the correlation of the spins of top quarks and antiquarks at the Tevatron and the LHC. Observation of the spin correlation would confirm that the top quark decays before its spin flips, and would place a lower bound on the top-quark width and V_tb. The spin correlation may also be a useful tool to study the weak decay amplitu

Fabian H. L. Essler, Holger Frahm, Alexander R. Its, Vladimir E. Korepin

We consider a completely integrable lattice regularization of the sine-Gordon model with discrete space and continuous time. We derive a determinant representation for a correlation function which in the continuum limit turns into the correlation function of local fields. The determinant is then embedded into a system of integrable integro-differential equat

J. Rahmfeld

We consider a simple static extremal multi-black hole solution with constituents charged under different $U(1)$ fields. Each of the constituents by itself is an extremal dilatonic black hole of coupling $a=\srt$. For a special case with two electrically and two magnetically charged black holes the multi-black hole solution interpolates between the familiar $

K. Goulianos

A phenomenological renormalization scheme for hadronic diffraction is proposed, which achieves unitarization without the need for &#34;screening corrections&#34;. Predictions for diffractive photoproduction cross sections at HERA are presented and compared with experimental results. A new interpretation of hard and deep inelastic diffractive data emerges, in

Ganesh Devaraj, Martin B. Einhorn

We calculate the leading contribution to the left-right asymmetry in polarized Møller scattering from the superpartners in the Minimal Supersymmetric Standard Model (MSSM), using an effective lagrangian approach. We determine the maximum asymmetry that can result from the superpartners in the MSSM under different scenarios, and discuss the feasibility of a h

A. V. Shtoff, Yu. Yu. Dmitriev, S. I. Gusarov

A new method is proposed to calculate the polarization vector of a molecule in a monochromatic external field in the anomalous-despersion domain. The method takes into account the instantaneous switching of the field. A simple modification of the method allows one to consider a more general switching procedure. As an illustration of the method Fourier compon

P. Finocchiaro, M. Belkacem, T. Kubo, V. Latora

We investigate the Equation of State (EOS) of classical systems having 300 and 512 particles confined in a box with periodic boundary conditions. We show that such a system, independently on the number of particles investigated, has a critical density of about 1/3 the ground state density and a critical temperature of about $2.5~ MeV$. The mass distribution

Norberto Salinas, Maria Victoria Velasco

We examine a purely geometric property of a point in the boundary of the numerical range of a (Hilbert space) operator that implies that such a point is a reducing essential eigenvalue of the given operator. Roughly speaking, such a property means that the boundary curve of the numerical range has infinite curvature at that point (we must exclude however lin

S. P. Novikov

We present a brief survey of the results of the Theory of Solitons from the viewpoint of the periodic theory including some new results in the theory of 2-dimensional periodic Schrodinger Operators. The main subjects are: Periodic Solitons and Algebraic Geometry, The Theory of Solitons and the String equation, Topologically trivial and nontrivial periodic tw

Srinandan Dasmahapatra, Paul Martin

We consider Diagram algebras, $\Dg(G)$ (generalized Temperley-Lieb algebras) defined for a large class of graphs $G$, including those of relevance for cubic lattice Potts models, and study their structure for generic $Q$. We find that these algebras are too large to play the precisely analogous role in three dimensions to that played by the Temperley-Lieb al

A M Semikhatov, I Yu Tipunin

We consider the sl(2) current algebra at level k=-4 when the sl(2) BRST operator is nilpotent. We formulate a spectral sequence converging to the cohomology of this BRST operator. At the second term of the spectral sequence, we observe an N=4 algebra. This algebra is generated in a c=-2 bosonic string whose BRST operator Q_{string} represents the next term i

G. Veneziano

After recalling a few basic concepts from cosmology and string theory, I will discuss the main ideas/assumptions underlying string cosmology and show how these lead to a two-parameter family of ``minimal&#34; models. I will then explain how to compute, in terms of those parameters, the spectrum of scalar, tensor and electromagnetic perturbations, point at th