June 1994 arXiv papers — page 2

G. Juettner, M. Karowski

The $sl_q(2)$-quantum group invariant spin 1/2 XXZ-Heisenberg model with open boundary conditions is investigated by means of the Bethe ansatz. As is well known, quantum groups for $q$ equal to a root of unity possess a finite number of ``good'' representations with non-zero q-dimension and ``bad'' ones with vanishing q-dimension. Correspondi

R. Brustein

Supersymmetry breaking in string theory is expected to occur when moduli fields acquire non-trivial expectation values. In the early universe these fields start out displaced from their final destinations. I present some recent ideas about the cosmological evolution of the dilaton modulus field on the way to its vacuum expectation value.

Subhendra Mohanty

We consider the low energy effective chiral theory of QCD mesons and the electroweak Goldstone bosons. In this effective theory the pion sector contributes to the gauge boson masses and the Yukawa couplings of the fermions. Consequently the Yukawa sector of quarks and leptons can have a $SU(2)_L\times U(1)_Y\times U(1)_A$ global symmetry even with nonvanishi

Manuel Drees

I discuss the minijet contribution to total photoproduction and photon--photon cross sections. While minijets with $p_T$ around 2 GeV have recently been observed directly in \gamgam\ experiments, the total \gamp\ cross section measured at HERA is in excellent agreement with predictions based on purely soft physics. Due to the large number of free parameters,

David London

I review the many ways of obtaining information about the CKM matrix through CP violation in the $B$ system. I include direct and indirect CP violation, the role of penguins and isospin analysis, tagging, and $B\to DK$ decays. I also discuss recent developments showing how to use $SU(3)$ flavor symmetry, along with some dynamical approximations, to extract f

M. Jeżabek

Top quark studies at future $e^+e^-$ colliders are considered. Two issues are discussed: {a --}Some results are presented on the decays of top quarks. Energy distributions of charged leptons and neutrinos in $t\to bW\to be^+ν$ and jets in $t\to bW\to b\bar du$ decays are sensitive to the structure of $tbW$ vertex. Distributions of charged leptons from top de

Dimitri Kalafatis

In this review we report on advances in topological soliton models of the nucleon. In chapter I we construct an effective lagrangian of QCD with the low mass mesons ($π,ρ,A_1$ and the scalar meson $ε$) generalising the Skyrme model. The vector meson fields are introduced as massive gauge fields in the linear sigma model and we look for topological soliton so

A. Dobado, A. Lopez

Whichever could be the real theory of gravitation, the corresponding low-energy effective lagrangian will probably contain higher derivative terms. In this work we study the general conditions on those terms in order to produce enough inflation to solve some of the problems of the standard Friedmann-Robertson-Walker cosmology in absence of any inflaton field

S. Hegyi

It is shown that there is a second properly normalized KNO scaling function, $nP_n(n/\bar n)=φ(z)$, which has certain advantages in the analysis of KNO scaling. First, the $nP_n$ are not influenced by the statistical and systematic uncertainties of $\bar n$ hence $φ(z)$ provides more selective power than the original KNO scaling function $\bar nP_n(n/\bar n)

Davison E. Soper, Levan R. Surguladze

We evaluate the effect of a virtual top quark on the coefficient of $α_{s}^{2}$ in the decay rates $Γ(Z \rightarrow {\rm hadrons})$ and $Γ(Z \rightarrow b\overline{b} )$. We treat the dependence on the top quark mass exactly instead of using a large mass expansion. The present work completes the evaluation of the $α_{s}^{2}$ contributions to these quantities

J. S. F. Chan, K. C. K. Chan, R. B. Mann

The phenomenon of mass inflation is shown to occur for a rotating black hole. We demonstrate this feature in $(2+1)$ dimensions by extending the charged spinning BTZ black hole to Vaidya form. We find that the mass function diverges in a manner quantitatively similar to its static counterparts in $(3+1)$, $(2+1)$ and $(1+1)$ dimensions.

Daniel S. Freed

This is an extended write-up of a talk given in April, 1993 in honor of Raoul Bott's 70th birthday. We first illustrate how some traditional topological and geometric invariants obey ``gluing laws'' inspired by those in classical and quantum field theory. Here we discuss characteristic numbers, particularly the Euler number of a complex line bund

Ana Lopez, Eduardo Fradkin

We generalize the fermion Chern-Simons theory for the Fractional Hall Effect (FQHE) which we developed before, to the case of bilayer systems. We study the complete dynamic response of these systems and predict the experimentally accessible optical properties. In general, for the so called $(m, m, n)$ states, we find that the spectrum of collective excitatio

G. Gompper, J. Goos

A simple Ginzburg-Landau theory with a single, scalar order parameter is used to study the microscopic structure of microemulsions and sponge phases. The scattering intensity in both film and bulk contrast, as well as averages of the internal area $S$, the Euler characteristic $χ_E$, and the mean curvature squared $<H^2>$, are calculated by Monte Carlo metho

Miles Osborne, Derek Bridge

This paper describes a grammar learning system that combines model-based and data-driven learning within a single framework. Our results from learning grammars using the Spoken English Corpus (SEC) suggest that combined model-based and data-driven learning can produce a more plausible grammar than is the case when using either learning style isolation.

Wayne Hu

With the rapidly growing number of cosmic microwave background measurements on various scales, there is real hope that the number of acceptable models for structure formation will be limited to a very few in the near future. Yet any given model can always be saved by introducing and tuning extraneous free parameters. To better understand this question of ``n

Stephen F King

We review the status of and recent developments in dynamical electroweak symmetry breaking, concentrating on the ideas of technicolour and top quark condensates. The emphasis is on the essential physical ideas and experimental implications rather than on detailed mathematical formalism.

Victor Pidstrigatch

We deduce some formulas for the spin invariants of the connected sum of an arbitrary 4-manifold X, b^+ _2(X) > 0 $ with $\overline {CP^2}$ in terms of the spin invariants of $X$ and apply this to prove the Van de Ven conjecture.

A. Dotsenko, O. Sushkov

Using the J_1-J_2 model, we present a description of quantum phase transition from Neel ordered to the spin-liquid state based on the modified spin wave theory. The general expression for the gap in the spectrum in the spin-liquid phase is presented.

B. D. Keister

Various methods of constructing solvable few-body models are reviewed, with an emphasis on direct interactions with few degrees of freedom, as an alternative to the use of local quantum field theories. Several applications are discussed.

R. Cenni, P. Saracco

In this paper we address the (charge) longitudinal electromagnetic response for a homogeneous system of nucleons interacting via meson exchanges in the functional framework. This approach warrants consistency if the calculation is carried on order-by-order in the mesonic loop expansion with RPA-dressed mesonic propagators. At the 1-loop order and considering

Abbas Ali

Worldsheet supersymmetric string action is written in duality invariant form for flat as well as curved backgrounds. First the action in flat backgrounds is written by introducing auxiliary fields. We also give the superfield form of this action and obtain the offshell supersymmetry algebra. The action has a modified Lorentz invariance and supersymmetry and

R. Brustein, M. Faux, B. Ovrut

We perform an explicit calculation of the lowest order effects of single eigenvalue instantons on the continuous sector of the collective field theory derived from a $d=1$ bosonic matrix model. These effects consist of certain induced operators whose exact form we exhibit.

Amit Giveon, Martin Rocek

We describe the duality between different geometries which arises by considering the classical and quantum harmonic map problem. To appear in ``Essays on Mirror Manifolds II&#39;&#39;.

G. Ferretti

We present some recently discovered infinite dimensional Lie algebras that can be understood as extensions of the algebra Map(M,g) of maps from a compact p-dimensional manifold to some finite dimensional Lie algebra g. In the first part of the paper, we describe the physical motivations for the study of these algebras. In the second part, we discuss their re

G. Papadopoulos

It is shown that non-trivial topological sectors can prevent the quantum mechanical implementation of the symmetries of the classical field equations of sigma models with torsion. The associated anomaly is computed, and it is shown that it depends on the homotopy class of the topological sector of the theory and the group action on the sigma model manifold t

R. W. Gebert, H. Nicolai

An attempt is made to understand the root spaces of Kac Moody algebras of hyperbolic type, and in particular $E_{10}$, in terms of a DDF construction appropriate to a subcritical compactified bosonic string. While the level-one root spaces can be completely characterized in terms of transversal DDF states (the level-zero elements just span the affine subalge

Marek Czachor

A new version of NLQM is formulated in terms of the generalized Nambu dynamics. The generalization is free from the difficulties of earlier approaches. The paper is a second part of &#34;Elements of NLQM (I): NL Schrodinger equation and two-level atoms&#34;.

Danny Birmingham, Mark Rakowski

It is shown that the standard mod-$p$ valued intersection form can be used to define Boltzmann weights of subdivision invariant lattice models with gauge group $Z_{p}$. In particular, we discuss a four dimensional model which is based upon the assignment of field variables to the $2$-simplices of the simplicial complex. The action is taken to be the intersec

N. Dorey, J. Hughes, M. Mattis

We establish the following fundamentals about Lagrangian models of meson-baryon interactions in the large-$N_{c}$ limit: 1. Calculating the leading-order contribution to $1$-meson/$2$-baryon Green&#39;s functions in the $1/N_c$ expansion involves summing an infinite class of divergent Feynman diagrams. So long as the bare Lagrangian properly obeys all large-

J. F. Gunion

The ability of LEP-200, the Tevatron, the Di-Tevatron, the LHC, and a next linear $\epem$ collider (NLC) to probe the Higgs sectors of the minimal Standard Model (SM) and the Minimal Supersymmetric Model (MSSM) is reviewed. Emphasis is placed on newly developed detection modes and on predictions for supersymmetric particle Higgs decay channels when the MSSM

S. Bauberger, F. A. Berends, M. Böhm, M. Buza

Motivated by the results of the electroweak precision experiments, studies of two-loop self-energy Feynman diagrams are performed. An algebraic method for the reduction of all two-loop self-energies to a set of standard scalar integrals is presented. The gauge dependence of the self-energies is discussed and an extension of the pinch technique to the two-loo

Pran Nath, R. Arnowitt

Analysis of the SUSY spectrum in supergravity unified models is given under the naturalness criterion that the universal scalar mass $(m_0)$ and the gluino mass $(m_{\tilde g})$ satisfy the constraint $m_0, m_{\tilde g}$ less than or equal to 1 TeV. The SUSY spectrum is analysed in four different scenarios: (1) minimal supergravity models ignoring proton dec

Masayasu Harada, Yuhsuke Yoshida

We calculate the low-energy parameter S in QCD, which is also known as L_{10}, and the pion decay constant f_πusing inhomogeneous Bethe-Salpeter equation in improved ladder approximation. To extract these quantities we calculate the ``V-A&#39;&#39; two-point function, Π_{VV}(q^2) - Π_{AA}(q^2), in space-like region. We obtain S = 0.43 \sim 0.48, which is abo

A. Denner, S. Dittmaier, G. Weiglein

Application of the background-field method to the electroweak Standard-Model yields a gauge-invariant effective action giving rise to simple Ward identities. We find that in the background-field `t Hooft-Feynman gauge the resulting vertex functions are exactly those that are obtained using the pinch technique. Thus, the background-field method provides a gen

Koichi Yamawaki, V. I. Zakharov

We argue that the extended Nambu-Jona-Lasinio model which introduces four-quark interactions to describe hadron physics at low energies can be confronted with fundamental quantum chromodynamics by means of spectral sum rules. While there arise rather restrictive bounds on the strength of the effective four-quark interaction in the vector channel, introductio

A. Yu. Ignatiev, G. C. Joshi, M. Matsuda

We suggest that Bose statistics for photons can be tested by looking for decays of spin-1 bosons into two photons. The experimental upper limit on the decay $Z \rightarrow γγ$ is used to establish for the first time the quantitative measure of the validity of Bose symmetry for photons.

C. Holm, W. Janke

We performed a high statistics simulation of Ising spins coupled to 2D quantum gravity on toroidal geometries. The tori were triangulated using the Regge calculus approach and contained up to $512^2$ vertices. We used a constant area ensemble with an added $R^2$ interaction term, employing the $dl/l$ measure. We find clear evidence that the critical exponent

M. Hasenbusch, K. Pinn, C. Wieczerkowski

We describe a new method to compute renormalized coupling constants in a Monte Carlo renormalization group calculation. The method can be used for a general class of models, e.g., lattice spin or gauge models. The basic idea is to simulate a joint system of block spins and canonical demons. In contrast to the Microcanonical Renormalization Group invented by

A. A. Kirillov

A new approach is suggested which allows to describe phenomenologically arbitrary topologies of the Universe. It consists in a generalizaton of third quantization. This quantization is carried out for the case of asymptotic closeness to a cosmological singularity. It is also pointed out that suggested approach leads to a modification of the ordinary quantum

Vladimir D. Ivashchuk, Vitaly N. Melnikov

The $n$-time generalization of Schwarzschild solution is considered. The equations of geodesics for the metric are integrated. The multitemporal analogues of Newton laws for the extended objects described by the solution are suggested. The scalar-vacuum generalization of the solution is also presented.

Stephen P. Braham

Recent work on an approach to the geometrodynamics of cylindrical gravity waves in the presence of interacting scalar matter fields, based on the Kuchař hypertime formalism, is extended to the analogous spherically symmetric system. This produces a geometrodynamical formalism for spherical black holes and wormholes in which the metric variables are divided i

P. L. Krapivsky, E. Ben-Naim, S. Redner

We investigate the kinetics of diffusion-controlled heterogeneous single-species annihilation, where the diffusivity of each particle may be different. The concentration of the species with the smallest diffusion coefficient has the same time dependence as in homogeneous single-species annihilation, A+A-->0. However, the concentrations of more mobile species

Lei Xing, Yia-Chung Chang

Thermal motion of the flux lines (FL) gives rise to fluctuating magnetic fields. These dynamic fields couple to the nuclei in the sample and relax the nuclear spins. Based on a model of harmonic fluctuations, we provide a theoretical description of the nuclear spin-lattice relaxation (NSLR) process due to the fluctuating FLs in clean type-II superconductors.

Johannes Kellendonk

For a large class of tilings, including those which are obtained by the generalized dual method from regular grids, it is shown that their algebra is stably isomorphic to a crossed product with $\Z^d$. Penrose tilings belong to this class. This enlarges the class of tilings of which can be shown that a set of possible gap labels is completely determined by a

M. Yu. Kuchiev, O. P. Sushkov

We consider two-dimensional t-J-V model. The wave function of the ground state is constructed. We demonstrate that the doping by holes results in condensation of the spin-waves, destruction of the long-range antiferromagnetic order and formation of the gap in the spin-wave spectrum.

A. C. C Coolen, D. Sherrington

We present a theory to describe the dynamics of the Sherrington- Kirkpatrick spin-glass with (sequential) Glauber dynamics in terms of deterministic flow equations for macroscopic parameters. Two transparent assumptions allow us to close the macroscopic laws. Replica theory enters as a tool in the calculation of the time- dependent local field distribution.

O. V. Dolgov, A. E. Karakozov, A. A. Mikhailovsky, B. J. Feenstra

We use the experimental technique of thermal modulation reflectometry to study the relatively small temperature dependence of the optical conductivity of superconductors. Due to a large cancellation of systematic errors, this technique is shown to a be very sensitive probe of small changes in reflectivity. We analyze thermal modulation reflection spectra of

Y. Berk, A. Kamenev, A. Palevski, L. N. Pfeiffer

The in-plane magnetic field suppresses the quantum coupling between electrons in a double quantum well structure. The microscopical theory of this effect is developed and confirmed experimentally. We have shown that the decrease of the &#34;resistance resonance&#34; peak is sensitive to the mutual orientation of the current and the in-plane magnetic field. T

Atro Voutilainen

The dissertation addresses the design of parsing grammars for automatic surface-syntactic analysis of unconstrained English text. It consists of a summary and three articles. {\it Morphological disambiguation} documents a grammar for morphological (or part-of-speech) disambiguation of English, done within the Constraint Grammar framework proposed by Fred Kar

David G. Novick, Stephen Sutton

We refine and extend prior views of the description, purposes, and contexts-of-use of acknowledgment acts through empirical examination of the use of acknowledgments in task-based conversation. We distinguish three broad classes of acknowledgments (other-->ackn, self-->other-->ackn, and self+ackn) and present a catalogue of 13 patterns within these classes t

Frank P. Pijpers, Ignaz Wanders

In this paper a new method is presented to find the transfer function of the broad-line region in active galactic nuclei. The subtractive optimally localized averages (SOLA) method is a modified version of the Backus-Gilbert method and is presented as an alternative to the more often used maximum-entropy method. The SOLA method has been developed for use in

Marc Kamionkowski, Bharat Ratra, David N. Spergel, Naoshi Sugiyama

We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At $Ω_0 \sim$ 0.3 -- 0.4, the COBE normalized open model appears to be consistent with most observations.

M. Bruni, S. Matarrese, O. Pantano

We investigate the local non--linear dynamics of irrotational dust with vanishing magnetic part of the Weyl tensor, $H_{ab}$. Once coded in the initial conditions, this dynamical restriction is respected by the relativistic evolution equations. Thus, the outcome of the latter are {\it exact solutions} for special initial conditions with $H_{ab}=0$, but with

Albert Stebbins, Shoba Veeraraghavan

In this paper we give a general expression for the energy shift of massless particles travelling through the gravitational field of an arbitrary matter distribution as calculated in the weak field limit in an asymptotically flat space-time. It is {\it not} assumed that matter is non-relativistic. We demonstrate the surprising result that if the matter is ill

Salman Habib, Henry E. Kandrup, M. Elaine Mahon

Results are reported from a numerical investigation of orbits in a truncated Toda potential which is perturbed by weak friction and noise. Two significant conclusions are shown to emerge: (1) Despite other nontrivial behaviour, configuration, velocity, and energy space moments associated with these perturbations exhibit a simple scaling in the amplitude of t

Ulrich Meyer

We show how to construct central and grouplike quantum determinants for FRT algebras A(R). As an application of the general construction we give a quantum determinant for the q-Lorentz group.

Andrea Brignole, Hitoshi Murayama, Riccardo Rattazzi

We study low-energy consequences of supersymmetric $SO(10)$ models with Yukawa unification $h_t = h_N$ and $h_b = h_τ$. We find that it is difficult to reproduce the observed $m_b/m_τ$ ratio when the third-generation right-handed neutrino is at an intermediate scale, especially for small $\tan β$. We obtain a conservative lower bound on the mass of the right

Evalyn Gates, Lawrence M. Krauss, Martin White

We describe how to consistently incorporate solar model uncertainties, along with experimental errors and correlations, when analyzing solar neutrino data to derive confidence limits on parameter space for proposed solutions of the solar neutrino problem. Our work resolves ambiguities and inconsistencies in the previous literature. As an application of our m

George Jikia

We study the signals for a heavy Higgs boson in the processes $γγ\to WWWW$, $γγ\to WWZZ$ at the photon linear collider. The results are based on the first complete tree level calculation for these reactions. Using a forward ``spectator&#34; $W$ tag, central ``spectator&#34; $W$ veto to suppress backgrounds from transverse $W$, $Z$ production we show that the

Salman Habib, Robert D. Ryne

The Lyapunov exponents of a chaotic system quantify the exponential divergence of initially nearby trajectories. For Hamiltonian systems the exponents are related to the eigenvalues of a symplectic matrix. We make use of this fact to develop a new method for the calculation of Lyapunov exponents of such systems. Our approach avoids the renormalization and re

Volker Koch

The scattering of antikaons with nucleons is studied in the nuclear environment. Describing the $\lam$ as a $K^-$ proton bound state, we find, that due to the Pauli blocking of intermediate states, the mass of the $Λ(1405)$ is shifted upwards in energy, above the $K^-$ proton threshold and and its width is somewhat broadened. As a consequence the s-wave $K^-

Shinji Hirano, Hiroshi Ishikawa

$\chat=1$ fermionic string theory, which is considered as a fermionic string theory in two dimension, is shown to decompose into two mutually independent parts, one of which can be viewed as a topological model and the other is irrelevant for the theory. The physical contents of the theory is largely governed by this topological structure, and the discrete p

Pankaj Jain, John P. Ralston

We study the energy and nuclear A dependence of the hadronic production of heavy quarkonia. We review theoretical ideas which have been put forward, seeking a consistent global picture reconciling the large effects in quarkonia with the small nuclear effects observed in continuum Drell Yan production. The data indicates that shadowing or leading twist modifi

Wolfgang Bock, Jeroen C. Vink

Regge&#39;s method for regularizing euclidean quantum gravity is applied to two dimensional gravity. We use two different strategies to simulate the Regge path integral at a fixed value of the total area: A standard Metropolis simulation combined with a histogramming method and a direct simulation using a Hybrid Monte Carlo algorithm. Using topologies with g

C. T. H. Davies, K. Hornbostel, A. Langnau, G. P. Lepage

The spectrum of the Upsilon system is investigated using the Nonrelativistic Lattice QCD approach to heavy quarks and ignoring light quark vacuum polarization. We find good agreement with experiment for the Upsilon(1S), Upsilon(2S), Upsilon(3S) and for the center of mass and fine structure of the chi_b states. The lattice calculations predict b-bbar D-states

N. G. Deshpande, Josip Trampetic

We calculate the semi-inclusive processes B $\rightarrow X_{s} η_c$ and relate it to B $\rightarrow X_{s} ψ$ in next to leading order QCD, and show how it can be used to determine an accurate value of $f_{η_{c}}$. The exclusive modes B $\rightarrow$ K$η_c$ and B $\rightarrow$ K$ψ$ also yield similar results, whereas B $\rightarrow$ K$^*η_c$ and B $\rightarro

J. Schwenk

We solve the problem of Fourier transformation for the one-dimensional $q$-deformed Heisenberg algebra. Starting from a matrix representation of this algebra we observe that momentum and position are unbounded operators in the Hilbert space. Therefore, in order to diagonalise the position operator in a momentum eigenbasis we have to study self-adjoint extens

L. Moriconi

We compute, neglecting possible effects of subleading irrelevant couplings, the localization length exponent in the integer quantum Hall effect, for the case of white noise random potentials. The result obtained is $ν=2$ for all Landau levels. Our approach consists in a renormalization group transformation of Landau orbitals, which iterates the generating fu

Francesca M. Borzumati, Manuel Drees, Mihoko M. Nojiri

We point out that combinations of parameters that predict large counting rates in experiments searching for supersymmetric dark matter often tend to predict a very large branching ratio for the inclusive decay \bsg. The recent measurement of this branching ratio, therefore, indicates that searches for supersymmetric dark matter might be even more difficult t

R. D. Ball, S. Forte

We show that recent data from HERA on the proton structure function $F_2$ at small $x$ and large $Q^2$ provide a direct confirmation of the double asymptotic scaling prediction of perturbative QCD. A linear rise of $\ln F_2$ with the scaling variable $σ$ is observed throughout the kinematic region probed at HERA, and the measured slope is in excellent agreem

Michael C. Birse

Partial restoration in nuclear matter of the chiral symmetry of QCD is discussed together with some of its possible signals. Estimates of corrections to the leading, linear dependence of the quark condensate are found to be small, implying a significant reduction of that condensate in matter. The importance of the pion cloud for the scalar quark density of a

Jose M. Gracia-Bondia, Joseph C. Varilly

We show how the Moyal product of phase-space functions, and the Weyl correspondence between symbols and operator kernels, may be obtained directly using the procedures of geometric quantization, applied to the symplectic groupoid constructed by ``doubling&#39;&#39; the phase space.

Denne Wesolowski, Yutaka Hosotani, Sumantra Chakravarty

A two-dimensional nonrelativistic fermion system coupled to both electromagnetic gauge fields and Chern-Simons gauge fields is analysed. Polarization tensors relevant in the quantum Hall effect and anyon superconductivity are obtained as simple closed integrals and are evaluated numerically for all momenta and frequencies. The correction to the energy densit

Mark S. Swanson

This paper is a generalization of previous work on the use of classical canonical transformations to evaluate Hamiltonian path integrals for quantum mechanical systems. Relevant aspects of the Hamiltonian path integral and its measure are discussed and used to show that the quantum mechanical version of the classical transformation does not leave the measure

Michel Dubois-Violette, Peter W. Michor

We characterize the derivation $d:A\to Ω^1_{\der}(A)$ by a universal property introducing a new class of bimodules.

H. B. Gao, H. Römer

In terms of the gauged nonlinear $σ$-models, we describe some results and implications of solving the following problem: Given a smooth symplectic manifold as target space with a quasi-free Hamiltonian group action, perform the symplectic blowing up of the point singularity and identify the blow-up modes in the corresponding (gauged) $σ$-model. Both classica

Dmitrij Sorokin

Considered are superparticle and superstring models invariant under supersymmetry in a target superspace and local extended worldsheet supersymmetry the latter replacing the fermionic $κ$--symmetry of the conventional Green--Schwarz formulations. (Talk given at the Conference on Geometry of Constrained Dynamical Systems, Cambridge, June 15-18, 1994).

Herbert W. Hamber, Ruth M. Williams

We show how the Newtonian potential between two heavy masses can be computed in simplicial quantum gravity. On the lattice we compute correlations between Wilson lines associated with the heavy particles and which are closed by the lattice periodicity. We check that the continuum analog of this quantity reproduces the Newtonian potential in the weak field ex

J. A. Gracey

We compute the $O(1/N^2)$ correction to the critical exponent $2λ$ $=$ $-$ $β^\prime(g_c)$ for the chiral Gross Neveu model in arbitrary dimensions by substituting the corrections to the asymptotic scaling forms of the propagators into the Schwinger Dyson equations and solving the resulting consistency equations.

M. Henneaux, S. Slavnov

It is shown that the phase space path integral for a system with arbitrary second class constraints (primary, secondary ...) can be rewritten as a configuration space path integral of the exponent of the Lagrangian action with some local measure.

Aneesh V. Manohar, Mark B. Wise

For high energy processes ($M\gg Λ_{QCD}$) there are infrared safe hadronic shape variables that have a calculable perturbative expansion in $α_s(M^2)$. However, nonperturbative power suppressed corrections to these variables are not well understood. We use the behavior of large orders of the perturbation expansion to gain insight into the nonperturbative co

D. Atwood, A. Soni

We consider CP violating effects in decays of the type $B^\pm\to γa^\pm_{1,2}$ where $a_{1,2}$ are the $J^P=1^+$ and $2^+$ resonances each decaying to the common final state via $a^\pm_{1,2} \toπ^\pmρ^0$. The resonances enhance the CP asymmetries and also knowledge of their masses and widths facilitates calculations of the effects. Several types of CP asymme

Pran Nath, R. Arnowitt

An analysis of the $b \rightarrow sγ$ is given in supergravity grand unification using the framework of the radiative breaking of the electro-weak symmetry under three separate sets of constraints:1) neutralino relic density does not overclose the universe,2)p-stability constraint, and 3) the combined constraints of p-stability and COBE data .For case 1 it i

C. S. Lam

A low energy string theory should reduce to an ordinary quantum field theory, but in reality the structures of the two are so different as to make the equivalence obscure. The string formalism is more symmetrical between the spacetime and the internal degrees of freedom, thus resulting in considerable simplification in practical calculations and novel insigh

G. R. Farrar, M. E. Shaposhnikov

Recent papers by Gavela et al. and Huet et al. claim to have shown that incluion of higher order interactions between quasiparticles dramatically decreases the baryon asymmetry of the universe which can arise in the Minimal Standard Model. These papers employ an inconsistent calculational scheme which, for instance, violates unitarity. We argue that their me

D. P. Roy, K. Sridhar

We compute the contributions due to gluon and heavy-quark fragmentation to quarkonium production at large transverse momentum in $\bar p p$ and $p p$ collisions. For inclusive $J/ψ$ production, there is a large contribution from the $g \rightarrow χ_c$ fragmentation. At large $p_T$, this is comparable to the conventional charmonium model prediction via gluon

Chr. V. Christov, A. Z. Górski, K. Goeke, P. V. Pobylitsa

In this paper we present the derivation as well as the numerical results for all electromagnetic form factors of the nucleon within the chiral quark soliton model in the semiclassical quantization scheme. The model is based on a semibosonized Nambu -- Jona-Lasinio lagrangean where the boson fields are treated as classical ones. Other observables, namely the

Arjan Hulsebos

We study the properties of vortex loops in the 3-d XY model. We find that the phase transition in this model is driven by the condensation of short loops into percolating loops. Paper comes as a uuencoded compressed tar-file, containing the complete PostScript file. Total file approx. 220 Kb.

M. Pentia, G. Iorgovan, A. Mihul

Particle track reconstruction capabilities of the silicon tracking detector system have been studied. As the multiple Coulomb scattering (MCS) induces unavoidable uncertainties on the coordinate measurement, the corresponding error estimates and the associated correlations have been used to find the best track fit parameters and their errors. Finally it perm

The CLEO Collaboration

We study the exclusive semileptonic B meson decays B- -> D*0 l- nu and B0 -> D*+ l- nu using data collected with the CLEO II detector at CESR. We present measurements of the branching fractions B(B0 -> D*+ l-nu) = 0.5/f00* [4.49+/-0.32+/-0.39]% and B(B- -> D*0 l-nu) = 0.5/f+-*[5.13+/-0.54+/-0.64]%, where f00 and f+- are the neutral and charged B meson produc

A. Carlini, J. Greensite

We point out that for a large class of parametrized theories, there is a constant in the constrained Hamiltonian which drops out of the classical equations of motion in configuration space. Examples include the mass of a relativistic particle in free fall, the tension of the Nambu string, and Newton&#39;s constant for the case of pure gravity uncoupled to ma

D. I. Golosov, A. E. Ruckenstein

We present a finite temperature calculation of the transverse spin-diffusion coefficient, $D_\bot$, in a dilute degenerate Fermi gas in the presence of a small external magnetic field, $H$. While the longitudinal diffusion coefficient displays the conventional low-temperature Fermi-liquid behavior, $D_\parallel \propto T^{-2}$, the corresponding results for

Chui-Lin Wang, Wen-Zheng Wang, Yu-Liang Liu, Zhao-Bin Su

The dynamic Jahn-Teller splitting of the six equivalent $D_{5d}$ polarons due to quantum fluctuations is studied in the framework of the Bogoliubov-de Gennes formalism. The tunneling induced level splittings are determined to be $^2 T_{1u} \bigoplus ^2 T_{2u}$ and $^1 A_g \bigoplus ^1 H_g$ for $C_{60}^{1-}$ and $C_{60}^{2-}$, respectively, which should give

R. Eder, Y. Ohta

We present a nonperturbative method for deriving a quasiparticle description of the low-energy excitations in the t-J model for strongly correlated electrons. Using the exact diagonalization technique we evaluated exactly the spectral functions of composite operators which describe an electron or hole dressed by antiferromagnetic spin fluctuations as expecte

D. van der Marel

The equations of motion of pair-like excitations in the superconducting state are studied for various types of pairing using the random phase approximation. The collective modes are computed of a layered electron gas described by a $t-t&#39;$ tight-binding band, where the electrons experience besides the long-range Coulomb repulsion an on-site Hubbard U repu

F. V. Kusmartsev, Minoru Takahashi

We find a fine structure in the Aharonov-Bohm effect, characterized by the appearence of a new type of periodic oscillations having smaller fractional period and an amplitude, which may compare with the amplitude of the conventional Aharonov-Bohm effect. Specifically, at low density or strong coupling on a Hubbard ring can coexist along with the conventional

J. M. Molera, F. C. Martinez, J. A. Cuesta, R. Brito

In this paper we present a theoretical analysis of a recently proposed two-dimensional Cellular Automata model for traffic flow in cities with the novel ingredient of turning capability. Numerical simulations of this model show that there is a transition between a freely moving phase with high velocity to a jammed state with low velocity. We study the dynami

Andrei Mushinski, M. P. Nightingale

Clusters of sizes ranging from two to five are studied by variational quantum Monte Carlo techniques. The clusters consist of Ar, Ne and hypothetical lighter (``$1 \over 2$-Ne&#34;) atoms. A general form of trial function is developed for which the variational bias is considerably smaller than the statistical error of currently available diffusion Monte Carl

Guillermo González-Casado, Gary A. Mamon, Eduard Salvador-Solé

We consider the dynamical evolution of small-scale substructure in clusters within two extreme alternate scenarios for their possible origin: 1) the accretion of groups (or small clusters) on quasi-radial orbits, and 2) the merger of clusters of similar masses, followed by the decoupling of their dense cores. Using simple analytical arguments and checking wi