October 1993 arXiv papers — page 6

David Seibert

I calculate the dispersion relation for quarks of mass $m$ and momentum $k$ in a quark gluon plasma at temperature $T$, in the limit $m^2+k^2 \gg (gT)^2$, where $g$ is the strong coupling constant. I find three contributions to the dispersion relation: one that depends on $T$ but not $m$ or $k$, one that depends on $m$ and $T$ but not $k$, and third contribu

Bille C. Carlson, John L. Gustafson

Symmetric elliptic integrals, which have been used as replacements for Legendre's integrals in recent integral tables and computer codes, are homogeneous functions of three or four variables. When some of the variables are much larger than the others, asymptotic approximations with error bounds are presented. In most cases they are derived from a uniform

T. Gisiger, M. B. Paranjape

We study the scattering of Skyrmions at low energy and large separation using the method proposed by Manton of truncation to a finite number of degree freedom. We calculate the induced metric on the manifold of the union of gradient flow curves, which for large separation, to first non-trivial order is parametrised by the variables of the product ansatz.

Jacobus Verbaarschot

We investigate the spectral properties of a random matrix model, which in the large $N$ limit, embodies the essentials of the QCD partition function at low energy. The exact spectral density and its pair correlation function are derived for an arbitrary number of flavors and zero topological charge. Their microscopic limit provide the master formulae for sum

C. Aragone, A. Khoudeir

We introduce the massive gauge invariant, second order pure spin-3 theory in three dimensions. It consists of the addition of the second order gauge invariant massless pure spin-3 action with the first order topological(generalized) Chern-Simons spin-3 term corrected with lower spin auxiliary actions which avoid lower spin ghosts propagation. This second ord

Youngjai Kiem

A class of 2-dimensional models including 2-d dilaton gravity, spherically symmetric reduction of d-dimensional Einstein gravity and other related theories are classically analyzed. The general analytic solutions in the absence of matter fields other than a U(1) gauge field are obtained under a new gauge choice and recast in the conventional conformal gauge.

K. Becker, M. Becker

We calculate two- and three-point tachyon amplitudes of the SL(2,R)/U(1) two-dimensional Euclidean black hole for spherical topologies in the continuum approach proposed by Bershadsky and Kutasov. We find an interesting relation to the tachyon scattering amplitudes of standard non-critical string theory.

Osmo Pekonen

Lipman Bers' universal Teichmüller space, classically denoted by $T(1)$, plays a significant role in Teichmüller theory, because all the Teichmüller spaces $T(G)$ of Fuchsian groups $G$ can be embedded into it as complex submanifolds. Recently, $T(1)$ has also become an object of intensive study in physics, because it is a promising geometric environment

N. Banerjee, Subir Ghosh, R. Banerjee

We quantise the $O(N)$ nonlinear sigma model using the Batalin Tyutin (BT) approach of converting a second class system into first class. It is a {\it nontrivial} application of the BT method since the quantisation of this model by the conventional Dirac procedure suffers from operator ordering ambiguities. The first class constraints, the BRST Hamiltonian a

N. Banerjee, Subir Ghosh, R. Banerjee

The $CP^{N-1}$ model is quantised in the generalised canonical formalism of Batalin and Tyutin by converting the original second class system into first class. Operator ordering ambiguities present in the conventional quantisation scheme of Dirac are thereby avoided. The first class constraints, the involutive Hamiltonian and the BRST charge are explicitly c

D. V. Boulatov

We give the formula for a simple Wilson loop on a sphere which is valid for an arbitrary QCD$_2$ saddle-point $ρ(x)$: \mbox{$W(A_1,A_2)=\oint \frac{dx}{2πi} \exp(\int dy \frac{ρ(y)}{y-x}+A_2x)$}. The strong-coupling-phase solution is investigated.

R. Fiore, D. Galeazzi, L. Masperi, A. Megevand

We have numerically calculated topological andnon-topological solitons in two spatial dimensions with Chern-Simons term. Their quantum stability, as well as that of the Maxwell vortex, is analyzed by means of bounce instantons which involve three-dimensional strings and non-topological solitons.

Min-Ho Lee, Hyeong-Chan Kim, Jae Kwan Kim

The effective action is derived for a self-interacting theory with a finite fixed $O(2)$ charge at finite temperature in curved spacetime. We obtain the high temperature expansion of the effective action in the weak coupling limit. In the relativistic temperature, we discuss about the phase transition in a homogeneous spacetime.

Ian I. Kogan

We consider the quantum state describing the Disoriented Chiral Condensate (DCC) which may be produced in high energy collisions. Using the approach suggested by Rajagopal and Wilczek to describe the amplification of the long wavelength classical pion modes, we consider the quantum-mechanical evolution of the initial vacuum state into the final squeezed stat

D. A. Morris, T. N. Truong, D. Zappala

We study interference effects between resonant and nonresonant amplitudes for the $γγ\rightarrow W^+ W^-$ process at a backscattered photon-photon collider. We show that a Higgs boson with $M_H$ > 200 GeV is manifest as a resonant dip in the $W^+W^-$ invariant mass spectrum and we investigate its statistical significance.

Xiao-Gang He, J. P. Ma, B. McKellar

We study CP violation in fermion pair decays of neutral boson particles with spin 0 or 1. We study a new asymmetry to measure CP violation in $η, K_L \rightarrow μ^+μ^-$ decays and discuss the possibility of measuring it experimentally. For the spin-1 particles case, we study CP violation in the decays of $J/ψ$ to $SU(3)$ octet baryon pairs. We show that the

Torbjörn Sjöstrand, Valery Khoze

We discuss the possibility of colour rearrangement in $\ee \to \W^+ \W^- \to \q_1 \qbar_2 \q_3 \qbar_4$ events, i.e.\ that the original colour singlets $\q_1 \qbar_2$ and $\q_3 \qbar_4$ may be transmuted, for instance, into new singlets $\q_1 \qbar_4$ and $\q_3 \qbar_2$. The effects on event properties could be quite large if such a rearrangement would occur

P. Zenczykowski

An explanation of the difference in the values of the apparent $f/d$ ratios for the S- and P- wave amplitudes of nonleptonic hyperon decays is proposed. The argument is formulated in the framework of the standard pole model with $(56,0^{+})$ ground-state and $(70,1^{-})$ excited baryons as intermediate states for the P- and S- waves respectively. Under the a

F. Butler, H. Chen, J. Sexton, A. Vaccarino

We evaluate $f_π/ m_ρ$, $f_K/ m_ρ$, $1/f_ρ$, and $ m_ϕ/(f_ϕ m_ρ)$, extrapolated to physical quark mass, zero lattice spacing and infinite volume, for lattice QCD with Wilson quarks in the valence (quenched) approximation. The predicted ratios differ from experiment by amounts ranging from 12\% to 17\% equivalent to between 0.9 and 2.8 times the corresponding

K. M. Bitar, P. M. Vranas

In an effort to investigate some of the low energy properties of QCD, in particular those related to chiral symmetry breaking, as well as to obtain insights on the behavior of an interacting theory of fermions on the lattice, the two flavor Nambu--Jona-Lasinio model with $SU(2) \times SU(2)$ chiral symmetry is studied on the four--dimensional hypercubic latt

Rajan Gupta, Tanmoy Bhattacharya, David Daniel

The form factors for the semileptonic decays of heavy-light pseudoscalar mesons of the type $D \to Keν$ are studied in quenched lattice QCD at $β=6.0$ using Wilson fermions. We explore new numerical techniques for improving the signal and study $O(a)$ corrections using three different lattice transcriptions of the vector current. We present a detailed discus

J. E. Nelson

To appear in proceedings of II Workshop on ``Constraints Theory and Quantisation Methods''Montepulciano (Siena) 1993} General discussion of the constraints of 2+1 gravity, with emphasis on two approaches, namely the second order and first order formalisms, and comparison with the four dimensional theory wherever possible. Introduction to an operator

T. Thiemann

The method of solution of the initial value constraints for pure canonical gravity in terms of Ashtekar's new canonical variables due to CDJ is further developed in the present paper. There are 2 new main results : 1) We extend the method of CDJ to arbitrary matter-coupling again for non-degenerate metrics : the new feature is that the 'CDJ-matrix&#3

T. Thiemann, H. A. Kastrup

We show that the quantization of spherically symmetric pure gravity can be carried out completely in the framework of Ashtekar's self-dual representation. Consistent operator orderings can be given for the constraint functionals yielding two kinds of solutions for the constraint equations, corresponding classically to globally nondegenerate or degenerate

E. Brezin, A. Zee

{Recently, we found that the correlation between the eigenvalues of random hermitean matrices exhibits universal behavior. Here we study this universal behavior and develop a diagrammatic approach which enables us to extend our previous work to the case in which the random matrix evolves in time or varies as some external parameters vary. We compute the curr

T. Padmanabhan, K. Subramanian

The recent detection of microlensing of stars of LMC by compact objects in the halo of our galaxy suggests that our galaxy is surrounded by a non-luminous halo made of compact objects with mass of about $(0.03-0.5) \msun$. The rate of detection could be consistent with the assumption that these halo objects are distributed with a softened isothermal profile

Rick Miranda, Peter F. Stiller

Given a torsion section of a semistable elliptic surface, we prove equidistribution results for the components of singular fibers which are hit by the section, and for the root of unity (identifying the zero component with ${\Bbb C}$) which is hit by the section in case the section hits the zero component.

Stefano Forte

Recent data on the Gottfried sum and less recent ones on the pion-nucleon sigma term seem to disagree with naive parton-based expectations on the light (i.e., up, down and strange) quark content of the nucleon. We show that these discrepancies are resolved if nonperturbative contributions are included in the analysis of the data. These appear both in the com

C. Alvarez, R. B. Mann

We discuss tests of the Einstein Equivalence Principle due to energies which are purely quantum mechanical in origin. In particular, we consider using Lamb Shift energies to test for possible quantum violations of Local Position Invariance. (to appear in the Proceedings of the 5th Canadian Conference on General Relativity and Relativistic Astrophysics, Unive

Julie Blum, Jeffrey A. Harvey

Topological defects constructed out of scalar fields and possessing chiral fermion zero modes are known to exhibit an anomaly inflow mechanism which cancels the anomaly in the effective theory of the zero modes through an inflow of current from the space in which the defect is embedded. We investigate the analog of this mechanism for defects constructed out

H. Saleur

We study some generic aspects of the winding angle distribution around a point in two dimensions for Brownian and self avoiding walks (SAW) using corner transfer matrix and conformal field theory.

R. Brustein, M. Faux, B. Ovrut

We discuss $d=1, {\cal N}=2$ supersymmetric matrix models and exhibit the associated $d=2$ collective field theory in the limit of dense eigenvalues. From this theory we construct, by the addition of several new fields, a $d=2$ supersymmetric effective field theory, which reduces to the collective field theory when the new fields are replaced with their vacu

Peter E. Haagensen, Yuri Kubyshin, Jose I. Latorre, Enrique Moreno

Through appropriate projections of an exact renormalization group equation, we study fixed points, critical exponents and nontrivial renormalization group flows in scalar field theories in $2<d<4$. The standard upper critical dimensions $d_k={2k\over k-1}$, $k=2,3,4,\ldots$ appear naturally encoded in our formalism, and for dimensions smaller but very close

C. M. Bender, A. Duncan, H. F. Jones

Recent proofs of the convergence of the linear delta expansion in zero and in one dimensions have been limited to the analogue of the vacuum generating functional in field theory. In zero dimensions it was shown that with an appropriate, $N$-dependent, choice of an optimizing parameter $ł$, which is an important feature of the method, the sequence of approxi

Daniel Arnaudon, Michel Bauer

When the parameter of deformation q is a m-th root of unity, the centre of U_q(sl(N))$ contains, besides the usual q-deformed Casimirs, a set of new generators, which are basically the m-th powers of all the Cartan generators of U_q(sl(N)). All these central elements are however not independent. In this letter, generalising the well-known case of U_q(sl(2)),

I. Jack, D. R. T. Jones

We derive an exact expression for the tachyon $β$-function for the Wess-Zumino-Witten model. We check our result up to three loops by calculating the three-loop tachyon $β$-function for a general non-linear $σ$-model with torsion, and then specialising to the case of the WZW model.

A. Leonidov

The two ways of resumming the efffective action for the massless test particles in inhomogeneous external field at zero and finite temperature providing the infrared finite answer are discussed. The case of the massive test particles having a mass which is parametrically small with respect to a scale set by the inhomogeneous external field is briefly conside

P. Maslanka

The induced \6s of the $κ$-\1 for the massive case are described. It is shown that it extends many of the features of the classical case.

M. Drees

After a brief review of recent data that confirm qualitative and quantitative predictions for resolved photon processes, a possible problem with the implementation of initial state showering in existing Monte Carlo event generators is pointed out. It is argued that this is responsible for the rather poor description of the jet rapidity distribution measured

Pankaj Jain, John P. Ralston

We review the theoretical formalism for hard exclusive processes in a nuclear medium. Theory suggests that these processes will show the very interesting phenomena of color transparency and nuclear filtering. The survival probability in nuclear media has also been predicted to show a scaling behavior at large momentum and large nuclear number. We show that a

S. Titard, F. F. Yndurain

We present an evaluation of heavy quarkonium states (bottomium and charmonium) from first principles. We use tree-level QCD (including relativistic corrections) and the full one-loop potential; nonperturbative effects are taken into account at the leading order through the contribution of the gluon condensate <alpha_strong G^2>. We use the values Lambda_QCD=

Kerson Huang

The Phi4 theory in 4-epsilon dimensions has two fixed points, which coincide in the limit epsilon->0. One is a Gaussian UV fixed point, and the other a non-trivial IR fixed point. They lead to two different continuum field theories. The commonly adopted IR theory is ``trivial,&#39;&#39; behaves like perturbation theory, and suggests an upper bound on the Hig

A. Anselm, M. Anselmino, F. Murgia, M. G. Ryskin

We calculate the spin density matrix of the hadron $h$ created via quark fragmentation in the process $e^-e^+ \to q\bar q \to h + X$. In the case of $h=Λ$ the experimental data could possibly elucidate the problem of $s$-quark contribution to the spin of the $Λ$-hyperon, to be compared with the case of the proton (``spin crisis&#39;&#39;). Generally we find

E. Laenen, J. Smith, W. L. van Neerven

The production rate for top quarks at the Fermilab Tevatron is presented using the exact order $α_s^3$ corrected cross section and the resummation of the leading soft gluon corrections in all orders of perturbation theory.

B. de Carlos, J. A. Casas

We calculate the region of the MSSM parameter space (i.e. $M_{1/2}$, $m_{0}$, $μ$, \ldots) compatible with a correct electroweak breaking and a realistic top-quark mass. To do so we have included {\em all} the one-loop corrections to the effective potential $V_{1}$ and checked their importance in order to obtain consistent results. We also consider the fine-

Claudio Coriano&#39;, Hsiang-nan Li

We perform a stability analysis of a recently proposed sum rule for pion Compton scattering at fixed angle and moderate Mandelstam invariants. The sum rule is found to be sensitive to the parameter $λ^2$, the contour radius of a generalized Borel transform. A modified phenomenological model for the continuum contribution is proposed to remove this dependence

Yigal Shamir

Chiral defect fermions in the background of an external, $2n$ dimensional gauge field are considered. Assuming first a finite extra dimension, we calculate the axial anomaly in a vector-like, gauge invariant model for arbitrary $n$, and the consistent anomaly in a gauge {\it variant} model with a chiral spectrum. For technical reasons, the latter calculation

L. P. Grishchuk

It is shown that rotational cosmological perturbations can be generated in the early Universe, similarly to gravitational waves. The generating mechanism is quantum-mechanical in its nature, and the created perturbations should now be placed in squeezed vacuum quantum states. The physical conditions under which the phenomenon can occur are formulated. The ge

Frank Gaitan

Results are presented of a numerical calculation of the tunneling gap for a domain wall moving in the double well potential of a pair of voids in a magnetic insulator. Both symmetric and asymmetric double well potentials are considered. It is found that, even in the absence of dissipation, the prospects for observing quantum coherence on a meso- or macro-sco

C. W. J. Beenakker

The smoothed correlation function for the eigenvalues of large hermitian matrices, derived recently by Brezin and Zee [Nucl. Phys. B402 (1993) 613], is generalized to all random-matrix ensembles of Wigner-Dyson type. Submitted to Nuclear Physics B[FS].

Michael Aizenman, Bruno Nachtergaele

A number of interesting features of the ground states of quantum spin chains are analized with the help of a functional integral representation of the system&#39;s equilibrium states. Methods of general applicability are introduced in the context of the SU($2S+1$)-invariant quantum spin-$S$ chains with the interaction $-P^{(0)}$, where $P^{(0)}$ is the proje

A. Serna, J. M. Alimi, H. Scholl

We have performed a series of N-body experiments on Connection Machine-5 in order to simulate the formation of galaxy clusters gravitationally dominated by a massive dark background. In accordance with previous authors we find an extremely inhomogeneous evolution where subcondensations are continually formed and merged. The final distribution of galaxies is

Fred C. Adams, Marco Fatuzzo, Richard Watkins

We study nonlinear wave phenomena in self-gravitating fluid systems, with a particular emphasis on applications to molecular clouds. This paper presents analytical results for one spatial dimension. We show that a large class of physical systems can be described by theories with a ``charge density&#39;&#39; $q(ρ)$; this quantity replaces the density on the r

Katherine Freese

A pseudo-Nambu-Goldstone boson, with a potential of the form $ V(ϕ) = Λ^4 [1 + \cos(ϕ/f)]$, can naturally give rise to an epoch of inflation in the early universe (Freese, Frieman, and Olinto 1990). The potential is naturally flat (as required by microwave background limits on the amplitude of density fluctuations), without any fine-tuning. Successful inflat

Victor V. Batyrev

We compute the quantum cohomology ring $H^*_φ({\bf P}, {\bf C})$ of an arbitrary $d$-dimensional smooth projective toric manifold ${\bf P}_Σ$ associated with a fan $Σ$. The multiplicative structure of $H^*_φ({\bf P}_Σ, {\bf C})$ depends on the choice of an element $avarphi$ in the ordinary cohomology group $H^2({\bf P}_Σ, {\bf C})$. There are many properties

F. Pisano, V. Pleitez, M. D. Tonasse

We consider, in the context of a 331 model with a single neutral right-handed singlet, the generation of lepton masses. At zeroth order two neutrinos and one charged lepton are massless, while the other leptons, two neutrinos and two charged leptons, are massive. However the charged ones are still mass degenerate. The massless fields get a mass through radia

Pierre van Baal, Bas van den Heuvel

For SU(2) gauge theories on the three-sphere we analyse the Gribov horizon and the boundary of the fundamental domain in the 18 dimensional subspace that contains the tunnelling path and the sphaleron and on which the energy functional is degenerate to second order in the fields. We prove that parts of this boundary coincide with the Gribov horizon with the

W. Melnitchouk, A. W. Thomas

Shadowing corrections to structure functions of heavy nuclei are calculated at very low values of Bjorken-$x$ and at values of the momentum transfer relevant to recent experiments. Good agreement is obtained with data from the E665 Collaboration for Xe/D and Pb/D, and with the NMC data on Ca/D and C/D structure function ratios. Corrections to the deuteron st

Nils A. Törnqvist

The systematics of deuteronlike two-meson bound states, {\it deusons}, is discussed. Previous arguments that many of the present non-$q\bar q$ states are such states are elaborated including, in particular, the tensor potential. For pseudoscalar states the important observation is made that the centrifugal barrier from the P-wave can be overcome by the $1/r^

A. Holt, T. Engeland, M. Hjorth-Jensen, E. Osnes

We calculate the spectra for the neutron deficient Sn isotopes with mass numbers from A=102 to A=108, using standard many-body techniques. The G-matrix used in the perturbative expansion was calculated using the Bonn potentials. A good agreement with the available data is obtained.

Klaus Morawetz, Dietrich Kremp

Within the $σ-ω$ model of coupled nucleon-meson systems, a generalized relativistic Lenard--Balescu--equation is presented resulting from a relativistic random phase approximation (RRPA). This provides a systematic derivation of relativistic transport equations in the frame of nonequilibrium Green&#39;s function technique including medium effects as well as

Edward Neuman, Patrick J. Van Fleet

Dirichlet averages of multivariate functions are employed for a derivation of basic recurrence formulas for the moments of multivariate Dirichlet splines. An algorithm for computing the moments of multivariate simplex splines is presented. Applications to hypergeometric functions of several variables are discussed.

Mourad E. H. Ismail, Mizan Rahman, Ruiming Zhang

We establish an integral representations of a right inverses of the Askey-Wilson finite difference operator in an $L^2$ space weighted by the weight function of the continuous $q$-Jacobi polynomials. We characterize the eigenvalues of this integral operator and prove a $q$-analog of the expansion of $e^{ixy}$ in Jacobi polynomials of argument $x$. We also ou

Antonio J. Durán, Walter Van Assche

It is well-known that orthogonal polynomials on the real line satisfy a three-term recurrence relation and conversely every system of polynomials satisfying a three-term recurrence relation is orthogonal with respect to some positive Borel measure on the real line. In this paper we extend this result and show that every system of polynomials satisfying some

B. Malcolm Brown, Mourad E. H. Ismail

We establish an integral representation of a right inverse of the Askey-Wilson finite difference operator on $L^2$ with weight $(1-x^2)^{-1/2}$. The kernel of this integral operator is $\vartheta&#39;_4/\vartheta_4$ and is the Riemann mapping function that maps the open unit disc conformally onto the interior of an ellipse.

Andreas Blass

We discuss the extent to which game semantics is implicit in the formalism of linear logic and in the intuitions underlying linear logic.

Andreas Blass

Techniques of combinatorial set theory are applied to the following algebraic problem. Suppose G is an abelian group such that, for all countable subgroups C, the divisible part of the quotient G/C is countable. What can one conclude about the size of the divisible part of G/K when the cardinality of the subgroup K is a given uncountable cardinal?

Dongsu Bak, D. Cangemi, R. Jackiw

We discuss general properties of the conservation law associated with a local symmetry. Using Noether&#39;s theorem and a generalized Belinfante symmetrization procedure in 3+1 dimensions, a symmetric energy-momentum (pseudo) tensor for the gravitational Einstein-Hilbert action is derived and discussed in detail. In 2+1 dimensions, expressions are obtained f

F. Ferrari

In this paper general abelian gauge field theories interacting with matter fields are quantized on a closed and orientable Riemann surface $Σ$. The approach used is that of small perturbations around topologically nontrivial classical solutions $A^I_μ$ of the Maxwell equations. The propagator of the gauge fields and the form of the fields $A^I_μ$ are explici

T. Kobayashi

We study the minimal supersymmetric standard model derived from the $Z_8$ orbifold models and its hidden sectors. We use a target-space duality anomaly cancellation so as to investigate hidden sectors consistent with the MSSM unification. For the allowed hidden sectors, we estimate the running gauge coupling constants making use of threshold corrections due

K. G. Chetyrkin, A. Kwiatkowski

We analytically compute the flavour singlet ${\cal O}(α_s^2 m_b^2/m_t^2)$ radiative corrections to the partial decay rate $Γ(Z\rightarrow b\bar{b})$. These corrections arise from anomalous ``double traingle&#39;&#39; diagrams containing a single $γ_5$ matrix inside each of two closed fermion loops. They represent the next-to-leading term of the asymptotic ex

Sean Gavin, Andreas Gocksch, Robert D. Pisarski

Rajagopal and Wilczek have proposed that relativistic nuclear collisions can generate domains in which the chiral condensate is disoriented. If sufficiently large ({\it i.e.} nucleus sized), such domains can yield measurable fluctuations in the number of neutral and charged pions. However, by numerical simulation of the zero-temperature two-flavor linear sig

R. Jakob, P. Kroll, M. Schuermann, W. Schweiger

We present an alternative parameterization of the quark-diquark model of baryons which particularly takes care of the most recent proton electric form-factor data from the E136 experiment at SLAC. In addition to electromagnetic form factors of the nucleon, for which good agreement with data is achieved, we discuss the weak axial vector form factor of the nuc

Kari Enqvist

Primordial nucleosynthesis constrains the properties of light, stable neutrinos. Apart from the well--known limit on the number of neutrino species, there are also bounds on neutrino masses and magnetic moments. I discuss also sterile neutrinos and neutrino propagation in a primordial magnetic field, such as could be the origin of the observed galactic magne

Yoshiki Kizukuri, Noriyuki Oshimo

$T$--violating asymmetry in chargino pair production processes is studied in the Minimal Supersymmetric Standard Model. The asymmetry emerges at the tree level in the production of two different charginos,and could be as large as of order $10^{-2}$ in unpolarized electron beam experiments and $10^{-1}$ in polarized electron beam experiments. In the pair prod

G. Bhattacharya, P. A. Kalyniak, K. A. Peterson

The pair production of charged heavy leptons via two photon fusion is considered for hadron collisions at SSC and LHC energies. Rates for the inelastic process $pp \rightarrow γγX \rightarrow L^+L^-X$ and the elastic process $pp \rightarrow γγpp \rightarrow L^+L^- pp$ are given in a Weizsäcker-Williams approximation and compared with production via the gluon

Stephen Sharpe, Apoorva Patel

We present results for one-loop matching coefficients between continuum four-fermion operators, defined in the Naive Dimensional Regularization scheme, and staggered fermion operators of various types. We calculate diagrams involving gluon exchange between quark lines, and ``penguin&#39;&#39; diagrams containing quark loops. For the former we use Landau gaug

Lin-Yuan Chen, Nigel Goldenfeld, Y. Oono, Glenn Paquette

We illustrate how to extend the concept of structural stability through applying it to the front propagation speed selection problem. This consideration leads us to a renormalization group study of the problem. The study illustrates two very general conclusions: (1) singular perturbations in applied mathematics are best understood as renormalized perturbatio

G. Bouzerar, D. Poilblanc, G. Montambaux

We calculate the persistent current of 1D rings of spinless fermions with short-range interactions on a lattice with up to 20 sites, and in the presence of disorder, for various band fillings. We find that {\it both} disorder and interactions always decrease the persistent current by localizing the electrons. Away from half-filling, the interaction has a muc

Kareljan Schoutens

We show that the recently constructed exact solution of the $SU(2|2)$ extended Hubbard model on a one-dimensional lattice provides a complete set of $4^L$ eigenstates of the hamiltonian, where $L$ is the length of the lattice.

Yu Chen, Hirotada Ohashi, Mamoru Akiyama

Abstracet: We present a new thermal lattice BGK model in D-dimensional space for the numerical calculation of fluid dynamics. This model uses a higher order expansion of equilibrium distribution in Maxwellian type. In the mean time the lattice symmetry is upgraded to ensure the isotropy of 6th order tensor. These manipulations lead to macroscopic equations f

Konrad Kuijken, John Dubinski

We describe an analytic distribution function of a finite, oblate stellar system that is useful for the practical modelling of dark halos. The function is determined by lowering Evans&#39;s (1993) distribution function of a flattened, cored isothermal system in analogy to the lowering of the singular, isothermal sphere in the definition of the King (1966) mo

John Dubinski, Dimitris Christodoulou

We construct models of highly-inclined (``polar&#39;&#39;) rings in an external potential including both self--gravity and dissipation due to a drag force. We adopt the oblate spheroidal scale--free logarithmic potential with axis ratio $q=0.85$ and an initial inclination of 80$^\circ$ for the self--gravitating rings. Stellar (dissipationless) rings suffer f

Victor V. Batyrev

We consider families ${\cal F}(Δ)$ consisting of complex $(n-1)$-dimensional projective algebraic compactifications of $Δ$-regular affine hypersurfaces $Z_f$ defined by Laurent polynomials $f$ with a fixed $n$-dimensional Newton polyhedron $Δ$ in $n$-dimensional algebraic torus ${\bf T} =({\bf C}^*)^n$. If the family ${\cal F}(Δ)$ defined by a Newton polyhed

Yujiro Kawamata

We give a simple proof of a theorem of Katz and Morrison.

Zheng Huang

We study a recent proposal to observe the disoriented chiral condensate in high energy collisions. In order to produce a large fluctuation in pion probability distribution, a large size of the correlated region is essential. We study the role of the intrinsic symmetry breaking and suggest that a negative (mass)^2 of mesons arising from a misaligned vacuum ma

Boris Feigin, Edward Frenkel

A homological construction of integrals of motion of the classical and quantum Toda field theories is given. Using this construction, we identify the integrals of motion with cohomology classes of certain complexes, which are modeled on the BGG resolutions of the associated Lie algebras and their quantum deformations. This way we prove that all classical int

Andreas S. Kronfeld

The role lattice QCD can play in $B$ physics is surveyed. We include results for the decay constant, and discuss upcoming calculations of semileptonic form factors and neutral-meson mixing. Together with experimental measurements, these calculations can determine the unitarity triangle. Plenary talk presented at the Workshop on $B$ Physics at Hadron Accelera

G. Lifschytz, M. Ortiz

The quantization of a massless conformally coupled scalar field on the 2+1 dimensional Anti de Sitter black hole background is presented. The Green&#39;s function is calculated, using the fact that the black hole is Anti de Sitter space with points identified, and taking into account the fact that the black hole spacetime is not globally hyperbolic. It is sh

Oleg A. Soloviev

The WZNW model at the Witten conformal point is perturbed by the sigma model term. It is shown that in the large level k limit the perturbed WZNW system with negative k arrives at the WZNW model with positive k.

J. M. Udias, P. Sarriguren, E. Moya de Guerra, E. Garrido

We present results for spectroscopic factors of the outermost shells in $^{40}$Ca and $^{208}$Pb, which have been derived from the comparison between the available quasielastic ($e,e&#39;p$) data from NIKHEF-K and the corresponding calculated cross-sections obtained within a fully relativistic formalism. We include exactly the effect of Coulomb distortion on

Pawel HAENSEL, Bernard PICHON CNRS

We study the consequences of recent progress in the experimental determination of masses of neutron rich nuclei for our knowledge of the ground state of cold dense matter. The most recent experimental data determine the ground state of cold dense matter up to $ ρ\simeq 10^{11}~{\rm g~cm^{-3}} $. The composition and the equation of state of the ground state o

Ravit Efraty

The leading, planar diagrams of the $1/N_c$ expansion and the usual string description suggest that quarks propagate on the boundary of a two-dimensional world surface. We restrict the quarks to the boundary of the world surface by giving them infinitely large mass on the interior of the surface and zero mass on its boundary and show that in this picture the

C. F. Kristjansen

We describe the idea of studying quantum gravity by means of dynamical triangulations and give examples of its implementation in 2, 3 and 4 space time dimensions. For $d=2$ we consider the generic hermitian 1-matrix model. We introduce the so-called moment description which allows us to find the complete perturbative solution of the generic model both away f

Marco Billo&#39;, Pietro Fre&#39;

We consider N=2 and N=4 supersymmetric gauge theories in two-dimensions, coupled to matter multiplets. In analogy with the N=2 case also in the N=4 case one can introduce Fayet-Iliopoulos terms.The associated three-parameters have the meaning of momentum-map levels in a HyperKähler quotient construction. Differently from the N=2 case, however, the N=4 has a

Lars Brink, Mikhail A. Vasiliev

We discuss lowest-weight representations of the $S_N$-Extended Heisenberg Algebras underlying the $N$-body quantum-mechanical Calogero model. Our construction leads to flat derivatives interpolating between Knizhnik-Zamolodchikov and Dunkl derivatives. It is argued that based on these results one can establish new links between solutions of the Knizhnik-Zamo

R. Brustein, M. Faux, B. Ovrut

We discuss $d=1, {\cal N}=2$ supersymmetric matrix models and exhibit the associated $d=2$ collective field theory in the limit of dense eigenvalues. From this field theory we construct, by the addition of several new fields, a $d=2$ supersymmetric effective field theory, which reduces to the collective field theory when the new fields are replaced with thei

Amit Giveon

Duality groups as (spontaneously broken) gauge symmetries for toroidal backgrounds, and their role in ($\infty$-dimensional) underlying string gauge algebras are reviewed. For curved backgrounds, it is shown that there is a duality in the moduli space of WZNW sigma-models, that can be interpreted as a broken gauge symmetry. In particular, this duality relate

A. P. Balachandran, G. Bimonte, E. Ercolessi, P. Teotonio-Sobrinho

There exists a physically well motivated method for approximating manifolds by certain topological spaces with a finite or a countable set of points. These spaces, which are partially ordered sets (posets) have the power to effectively reproduce important topological features of continuum physics like winding numbers and fractional statistics, and that too o

A. Nersessian

It is shown, that the geometrical objects of Batalin-Vilkovisky formalism-- odd symplectic structure and nilpotent operator $Δ$ can be naturally uncorporated in Duistermaat--Heckman localization procedure. The presence of the supersymmetric bi-Hamiltonian dynamics with even and odd symplectic structure in this procedure is established. These constructions ca