July 1994 arXiv papers — page 4

C. G. Torre

We define a natural generalized symmetry of the Yang-Mills equations as an infinitesimal transformation of the Yang-Mills field, built in a local, gauge invariant, and Poincaré invariant fashion from the Yang-Mills field strength and its derivatives to any order, which maps solutions of the field equations to other solutions. On the jet bundle of Yang-Mills

Susumu Okubo

We have new solutions to the Yang-Baxter equation, from which we have constructed new link invariants containing more than two arbitrary parameters. This may be regarded as a generalization of the Jones' polynomial. We have also found another simpler invariant which discriminates only the linking structure of knots with each other, but not details of ind

M. Eliashvili

FQHE is presented in the form of non-unitary singular similarity transformation, which relates the Laughlin wave function (and its particle-hole conjugate) to the composite quasi- particle incompressible ground state. (ENSLAPP-A-478/94)

James Steele, Jacobus Verbaarschot, Ismail Zahed

We construct the gauge invariant fermion correlator in the Schwinger model on the torus. At zero temperature, this correlator falls off with a rate given by the Coulomb energy of an infinitely heavy charge. At high temperature, the screening mass approaches $πT/2$, and this in the presence of a mass gap. The fractional Matsubara frequency arises from the act

Israel Gelfand, D. Krob, Alain Lascoux, B. Leclerc

This paper presents a noncommutative theory of symmetric functions, based on the notion of quasi-determinant. We begin with a formal theory, corresponding to the case of symmetric functions in an infinite number of independent variables. This allows us to endow the resulting algebra with a Hopf structure, which leads to a new method for computing in descent

A. Ferrando, A. Jaramillo

We define pure gauge $QCD$ on an infinite strip of width $L$. Techniques similar to those used in finite $TQCD$ allow us to relate $3D$-observables to pure $QCD_2$ behaviors. The non triviality of the $L \arrow 0$ limit is proven and the generalization to four dimensions described. The glueball spectrum of the theory in the small width limit is calculated an

E. Elizalde, S. D. Odintsov, Yu. I. Shil'nov

We formulate the Schwinger-Dyson equations in the ladder approximation for 2D induced quantum gravity with fermions using covariant gauges of harmonic type. It is shown that these equations can be formulated consistently in a gauge of Landau type (for negative cosmological constant). A numerical analysis of the equations hints towards the possibility of chir

Piotr A. Raczka

Renormalization scheme uncertainties in the next-next-to-leading order QCD predictions are discussed. To obtain an estimate of these uncertainties it is proposed to compare predictions in all schemes that do not have unnaturally large expansion coefficients. A concrete prescription for eliminating the unnatural schemes is given, based on the requirement that

G. Buchalla, A. J. Buras

We generalize the existing analyses of the parity violating muon polarization asymmetry $Δ_{LR}$ in $K^+\toπ^+μ^+μ^-$ beyond the leading logarithmic approximation. The inclusion of next--to--leading QCD corrections reduces the residual dependence on the renormalization scales, which is quite pronounced in the leading order. This leads to a considerably impro

Tzu Chiang Yuan

In the fragmentation of a heavy quark into a heavy meson whose light degrees of freedom have angular momentum $3/2$, all the helicity probabilities are completely determined in the heavy quark limit up to a single probability $w_{3/2}$. We point out that this probability depends on the longitudinal momentum fraction $z$ of the meson and on its transverse mom

Martin J. Savage

We discuss the recent developments in inclusive decays of hadrons containing a heavy quark. The subject is approached in a model independent way using an operator product expansion for the time-ordered product of weak currents. We discuss the extraction of the weak mixing angle $|V_{cb}|$ from inclusive semileptonic $B$ decays and the application of these te

A. H. Hoang, M. Jeżabek, J. H. Kühn, T. Teubner

The rate for the production of massive fermions radiated off a pair of massless fermions is calculated analytically. Combined with the analytic calculation of the corresponding virtual contribution one obtains the order $α^2$ correction to the cross section which is induced by the real and virtual radiation of a pair of massive fermions by massless fermions.

A. J. Askew, D. Graudenz, J. Kwiecinski, A. D. Martin

We calculate the rate for the deep-inelastic electroproduction of dijets at HERA. We study the weakening of the azimuthal (back-to-back) correlation between the jets, as $x$ decreases, to see whether it can be used to identify BFKL dynamics from conventional fixed-order QCD effects. We show how this may give information on the transverse momentum ($k_T)$ dep

R. D. Bowler, M. C. Birse

We solve a nonlocal generalisation of the NJL model in the Hartree approximation. This model has a separable interaction, as suggested by instanton models of the QCD vacuum. The choice of form factor in this interaction is motivated by the confining nature of the vacuum. A conserved axial current is constructed in the chiral limit of the model and the pion p

O. Bertolami, P. V. Moniz

Decoherence of Friedmann-Robertson-Walker (FRW) geometries due to massive vector fields with $SO(3)$ global symmetry is discussed in the context of Quantum Cosmology. (Talk presented at the 3rd National Meeting of Astronomy and Astrophysics, July 1993, IST, Lisboa, Portugal. -- A more complete version will be presented at MG7 conference and in the report CER

Jose' P. S. Lemos

The Einstein-Hilbert action with a cosmological term is used to derive a new action in 1+1 spacetime dimensions. It is shown that the two-dimensional theory is equivalent to planar symmetry in General Relativity. The two-dimensional theory admits black holes and free dilatons, and has a structure similar to two-dimensional string theories. Since by construct

F. Alcalde-Cuesta, G. Hector

A symplectic integration of a Poisson manifold $(M,Λ)$ is a symplectic groupoid $(Γ,η)$ which realizes the given Poisson manifold, i.e. such that the space of units $Γ_0$ with the induced Poisson structure $Λ_0$ is isomorphic to $(M,Λ)$. This notion was introduced by A. Weinstein in order to quantize Poisson manifolds by quantizing their symplectic integrati

Michael S. Farber, Jerome P. Levine

We study the eta-invariant, defined by Atiyah-Patodi-Singer a real valued invariant of an oriented odd-dimensional Riemannian manifold equipped with a unitary representation of its fundamental group. When the representation varies analytically, the corresponding eta-invariant may have an integral jump, known also as the spectral flow. The main result of the

P. L. Krapivsky, E. Ben-Naim

We introduce a simple geometric model which describes the kinetics of fragmentation of d-dimensional objects. In one dimension our model coincides with the random scission model and show a simple scaling behavior in the long-time limit. For d>1, the volume of the fragments is characterized by a single scale 1/t, while other geometric properties such as the l

Beryl Hoffman

Turkish has considerably freer word order than English. The interpretations of different word orders in Turkish rely on information that describes how a sentence relates to its discourse context. To capture the syntactic features of a free word order language, I present an adaptation of Combinatory Categorial Grammars called {}-CCGs (set-CCGs). In {}-CCGs, a

G. J. Chaitin

This is yet another version of the course notes in chao-dyn/9407003. Here we change the universal Turing machine that is used to measure program-size complexity so that the constants in our information-theoretic incompleteness theorems are further reduced. This is done by inventing a more complicated version of lisp in which the parentheses associating defin

Marc Kamionkowski

In this talk, I review some recent work on cosmic microwave background (CMB) anisotropies in an open universe. I emphasize that the observed CMB anisotropies are still consistent with a low value of $Ω$, and I address the question of whether future CMB measurements will be able to provide information on the geometry of the Universe.

J. G. Bartlett, A. Blanchard, J. Silk, M. S. Turner

Although cosmologists have been trying to determine the value of the Hubble constant for nearly 65 years, they have only succeeded in limiting the range of possibilities: most of the current observational determinations place the Hubble constant between 50 km/s/Mpc and 90 km/s/Mpc. The uncertainty is unfortunate because this fundamental parameter of cosmolog

David Wands

I give a general formulation of the constraints on models of inflation ended by a first order phase transition arising from the requirement that they do not produce too many large (observable) true vacuum voids -- the `big bubble problem'. It is shown that this constraint can be satisfied by a simple model in Einstein gravity -- a variant of `hybrid'

F. Caputo, S. Degl'Innocent

Isochrone computations and horizontal branch (HB) models for Y(MS)=0.23 and two values of Z (0.0001, 0.0004)are used to derive constraints on the age indicators and HB morphology of metal-poor clusters with age t (in Gyrs) in the range of 1< t < 20.It is found that for fixed metallicity the luminosity L(3.83) of the zero age horizontalbranch (ZAHB) at the RR

Edward L. Wright

Some of the technical details involved in taking and analyzing data from COBE are discussed, and recent results from the FIRAS and DMR experiments are summarized. Some of the cosmological implications of these recent data are presented.

C. Destri, H. J. de Vega

We present a unified approach to the Thermodynamic Bethe Ansatz (TBA) for magnetic chains and field theories that includes the finite size (and zero temperature) calculations for lattice BA models. In all cases, the free energy follows by quadratures from the solution of a {\bf single} non-linear integral equation (NLIE). [A system of NLIE appears for nested

V. D. Ivashchuk, V. N. Melnikov

The multidimensional cosmological model describing the evolution of $n$ Einstein spaces in the presence of multicomponent perfect fluid is considered. When certain restrictions on the parameters of the model are imposed, the dynamics of the model near the singularity is reduced to a billiard on the $(n-1)$-dimensional Lobachevsky space $H^{n-1}$. The geometr

O. Ganor, J. Sonnenschein, S. Yankielowicz

We calculate the partition function of the $SU(N)$ ( and $U(N)$) generalized $YM_2$ theory defined on an arbitrary Riemann surface. The result which is expressed as a sum over irreducible representations generalizes the Rusakov formula for ordinary YM_2 theory. A diagrammatic expansion of the formula enables us to derive a Gross-Taylor like stringy descripti

R. Foot

There has been some speculation about the possible existence of a second photon which only couples to ordinary matter through mixing of the gauge kinetic terms. If the exotic photon is massless, then the principle phenomenological effect of the kinetic mixing is to give the mirror particles small electric charges (mini-charged particles). We examine the poss

W. Peters, U. Mosel, A. Engel

We calculate the cross section for the production of $η$-mesons via \mbox{$ΔN \to N N η$} in a relativistic One-Boson-Exchange-Model. Using this cross section we then determine the probability for the production of an $η$-meson by a $Δ$-resonance moving in nuclear matter. The result is compared to prescriptions in BUU-calculations in which \et-production pro

K. C. Bowler

We calculate the leading-order matrix element for exclusive decays of $b \to s\gamma$ in the quenched approximation of lattice QCD on a $24^3\times48$ lattice at $\beta=6.2$, using an O(a)-improved fermion action. The matrix element is used to extract the on-shell form factor $T_1(q^2=0)$ for $B \to K^*\gamma$ and $B_s \to \phi\gamma$, using two different as

Jonathan M. Evans, Timothy J. Hollowood

A series of sigma models with torsion are analysed which generate their mass dynamically but whose ultra-violet fixed points are non-trivial conformal field theories -- in fact SU(2) WZW models at level $k$. In contrast to the more familiar situation of asymptotically free theories in which the fixed points are trivial, the sigma models considered here may b

Marilyn Walker, Owen Rambow

A discourse planner for (task-oriented) dialogue must be able to make choices about whether relevant, but optional information (for example, the &#34;satellites&#34; in an RST-based planner) should be communicated. We claim that effective text planners must explicitly model aspects of the Hearer&#39;s cognitive state, such as what the hearer is attending to

G. J. Gounaris, F. M. Renard, G. Tsirigoti

We study a picture of effective interactions among the $W$ and Higgs bosons which is consistent with the precision tests at present energies, and at the same time allows for large observable New Physics (NP) effects in the bosonic sector. Toy dynamical models containing new heavy particles are used to indicate how such a picture could be created by integrati

Raghavan Rangarajan

We calculate the dilution of the baryon-to-photon ratio by the decay of superstring axions. We find that the dilution is of the order of $10^7$. We review several models of baryogenesis and show that most of them can not tolerate such a large dilution. In particular, only one current model of electroweak baryogenesis possibly survives. The Affleck-Dine mecha

Raghavan Rangarajan

We consider the cosmological and astrophysical constraints on the decay of massive $E_8 \times E_8^\prime$ superstring axions associated with the hidden sector. We find that decay lifetimes greater than 1 s are ruled out by limits from nucleosynthesis, by limits on the distortion of the cosmic microwave and gamma ray backgrounds and by closure arguments. We

V. E. Adler

The new integrable mapping with a simple geometric interpretation is presented. This mapping arise from the nonlinear superposition principle for the Bäcklund transformations of some vector evolution equation.

Richard A. Arndt Igor I. Strakovsky, Ron Workman

An energy-dependent and a set of single-energy partial-wave analyses of $π$d elastic scattering data have been completed. Amplitudes are presented for pion laboratory kinetic energies up to 500~MeV. These results are compared with those found in other recent analyses. We comment on the present database and make suggestions for future work. ( Figures are avai

B. F. Gibson, H. Kohlhoff, H. V. von Geramb, G. L. Payne

We report 3H binding energy calculations using inversion potentials generated from phase shifts corresponding to contemporary nucleon-nucleon potentials as well as modern phase shift analyses. We place limits upon local potential triton binding energy calculations due to the underlying uncertainties in their fit to the nucleon-nucleon phase shifts: 7.7 +/- 0

Valery I. Abrosimov, Helmut Hofmann

The Landau-Vlasov equation is applied to a slab of width $L$. This geometry is introduced to simulate somehow the finiteness of real nuclei but to allow for analytical solutions, nevertheless. We focus on the damping of low frequency surface modes and discuss their friction coefficient. For this quantity we study the macroscopic limit as defined by $L\to \in

K. S. Virbhadra, J. C. Parikh

An exact solution of Einstein - Maxwell - conformal scalar field equations is given, which is a black hole solution and has three parameters: scalar charge, electric charge, and magnetic charge. Switching off the magnetic charge parameter yields the solution given by Bekenstein. In addition the energy of the conformal scalar dyon black hole is obtained.

Meifang Chu, Peter Goddard

The Hilbert space of a free massless particle moving on a group manifold is studied in details using canonical quantisation. While the simplest model is invariant under a global symmetry, $G \times G$, there is a very natural way to ``factorise&#34; the theory so that only one copy of the global symmetry is preserved. In the case of $G=SU(2)$, a simple defor

Jaap Kalkman

In this paper we obtain an expression for the residue as it occurs in the non-Abelian localization formula due to Jeffrey and Kirwan. This expression can be used in cohomology computations for symplectic quotients.

M. I. Eides, I. B. Khriplovich, A. I. Milstein

The physical origin of the $mα^5$ radiative corrections to $P$-levels in the two-body QED problem is elucidated. Then we demonstrate that the next order, $mα^6$, corrections to those levels are due to the anomalous magnetic moment only.

M. Consoli, P. M. Stevenson

The real meaning of `triviality&#39; of (lambda Phi^4)_4 theory is outlined. Assuming `triviality&#39; leads to an effective potential that is just the classical potential plus the zero-point energy of the free-field fluctuations. This V_{eff} gives spontaneous symmetry breaking. Its proper renormalization has the consequence that all scattering amplitudes v

M. M. Guzzo, O. L. G. Peres, V. Pleitez, R. Zukanovich Funchal

We investigate the solar neutrino problem in the scenario of three generation neutrino oscillation hypothesis, taking into account other phenomenological constraints to the neutrino mixing and mass parameters.

Jon Pumplin

I examine the phenomenology of particle multiplicity distributions, with special emphasis on the low multiplicities that are a background in the study of rapidity gaps. In particular, I analyze the multiplicity distribution in a rapidity interval between two jets, using the HERWIG QCD simulation with some necessary modifications. The distribution is not of t

F. Hussain, G. Thompson

We use the LSZ reduction theorem and interpolating fields, alongwith the heavy quark effective theory, to investigate the structure of the Bethe-Salpeter amplitude for heavy hadrons. We show how a simple form of this amplitude, used extensively in heavy hadron decay calculations, follows naturally upto $O(1/M)$ from these field theoretic considerations.

Minos Axenides, Andrei Johansen, Yuri Makeenko

We consider the problem of multiparticle production at threshold in a $ϕ^4$-theory with an $O(N_1$$+$$N_2)$ symmetry softly broken down to $O(N_1)\times O(N_2)$ by nonequal masses. We derive the set of recurrence relations between the multiparticle amplitudes which sums all relevant diagrams with arbitrary number of loops in the large-$N$ limit with fixed nu

F. De Campos, M. A. Garcia-JareÑO, Anjan S. Joshipura, J. Rosiek

Many extensions of the standard electroweak model Higgs sector suggest that the main Higgs decay channel is &#34;invisible&#34;, for example, $h \to J J$ where $J$ denotes the majoron, a weakly interacting pseudoscalar Goldstone boson associated to the spontaneous violation of lepton number. In many of these models the Higgs boson may also be produced in ass

B. Bajc, A. H. Blin, B. Hiller, M. C. Nemes

We calculate the momentum dependence of three particle vertices $σγγ$, $σργ$ and $σρρ$ in the context of a Nambu Jona Lasinio type model. We show how they influence the processes $γγ\rightarrow σ\rightarrow ππ$, $ρ\rightarrow γσ$ and $γγ\rightarrow ρρ$ and how chiral symmetry shadows the presence of the $σ$.

S. Lupia, A. Giovannini, R. Ugoccioni

Clan structure analysis in rapidity intervals is generalized from negative binomial multiplicity distribution to the wide class of compound Poisson distributions. The link of generalized clan structure analysis with correlation functions is also established. These theoretical results are then applied to minimum bias events and evidentiate new interesting fea

Ernest Baver, Miriam Leurer

Light first generation leptoquarks are being hunted for in HERA and at FNAL and there are various proposals for further searches in future machines. Such leptoquarks are however problematic from a theoretical point of view: Low energy precision measurements imply strong constraints on the couplings of the leptoquarks, and up till now the fulfilment of these

C. S. Kim, E. Mirkes

The polar and azimuthal angular distributions for the lepton pair arising from the decay of a J/psi meson produced at transverse momentum p_T balanced by a photon [or gluon] in hadronic collisions are calculated in the color singlet model (CSM). It is shown that the general structure of the decay lepton distribution is controlled by four invariant structure

M. Fukugita, Y. Kuramashi, H. Mino, M. Okawa

An exploratory study is made of the nucleon-nucleon $s$-wave scattering lengths in quenched lattice QCD with the Wilson quark action. The $π$-$N$ and $π$-$π$ scattering lengths are also calculated for comparison. The calculations are made with heavy quarks corresponding to $m_π/m_ρ\approx 0.73-0.95$. The results show that the $N$-$N$ system has an attractive

Bruce Allen, Paul Casper, Adrian Ottewill

We modify the recent analytic formula given by Allen and Casper for the rate at which piecewise linear cosmic string loops lose energy to gravitational radiation to yield the analogous analytic formula for the rate at which loops radiate momentum. The resulting formula (which is exact when the effects of gravitational back-reaction are neglected) is a sum of

Ted Jacobson

The purpose of this note is to establish the basic properties--- regularity at the horizon, time independence, and thermality--- of the generalized Hartle-Hawking vacua defined in static spacetimes with bifurcate Killing horizon admitting a regular Euclidean section. These states, for free or interacting fields, are defined by a path integral on half the Euc

Alexander Reznikov

We prove the Bloch conjecture : $ c_2(E) \in H^4_\cald (X,\bbz(2))$ is torsion for holomorphic rank two vector bundles $E$ with an integrable connection over a complex projective variety $X$. We prove also the rationality of the Chern-Simons invariant of compact arithmetic hyperbolic three-manifolds. We give a sharp higher-dimensional Milnor inequality for t

M. C. Chang, Q. Niu

In this paper we study the energy spectrum of a two dimensional electron gas (2DEG) in a two dimensional periodic magnetic field. Both a square magnetic lattice and a triangular one are considered. We consider the general case where the magnetic field in a cell can be of any shape. A general feature of the band structure is bandwidth oscillation as a functio

A. Alan Middleton, Chao Tang

The origin of self-organized criticality in a model without conservation law (Olami, Feder, and Christensen, Phys. Rev. Lett. {\bf 68}, 1244 (1992)) is studied. The homogeneous system with periodic boundary condition is found to be periodic and neutrally stable. A change to open boundaries results in the invasion of the interior by a ``self-organized&#39;&#3

P. Šmilauer, M. Kotrla

We present results of numerical simulations of kinetic roughening for a growth model with surface diffusion (the Wolf-Villain model) in 3+1 and 4+1~dimensions using lattices of a linear size up to $L=64$ in 3+1~D and $L=32$ in 4+1~D. The effective exponents calculated both from the surface width and from the height--height correlation function are much large

N. Manini, E. Tosatti, S. Doniach

We show that electron hopping in a lattice of molecules possessing a Berry phase naturally leads to pairing. Our building block is a simple molecular site model inspired by C$_{60}$, but realized in closer similarity with Na$_3$. In the resulting model electron hopping must be accompanied by orbital operators, whose function is to switch on and off the Berry

Clint McCrory, Adam Parusinski

We study the Euler characteristic of the real Milnor fibres of a real analytic map, using a relation between complex monodromy and complex conjugation. We deduce the result of Coste and Kurdyka that the Euler characteristic of the link of an irreducible algebraic subset of a real algebraic set is generically constant modulo 4. We generalize this result to it

A. Dobado, J. Morales

We compute the large $N$ effective action of the $O(N+1)/O(N)$ non-linear sigma model including the effect of the pion mass to order $m^2_{\pi}/f_{\pi}^2$. This action is more complex than the one corresponding to the chiral limit not only because of the pion propagators but also because chiral symmetry produce new interactions proportional to $m^2_{\pi}/f_{

M. A. Moinester, D. Ashery, L. G. Landsberg, H. J. Lipkin

The strange-anticharmed Pentaquark is a uud(cbar)s or udd(cbar)s five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong decay. We describe this hyperon here; its structure, binding energy and lifetime, resonance width, production mechanisms and decay modes. We estimate production cross sections, techniques

A. Sudbery

This is (hopefully) a Latexable version of a talk given at the XXX Winter School in Theoretical Physics at Karpacz in February 1994. It discusses the use of non-commutative differential calculus to construct a Lie algebra of a quantum group. Usually the result has a different dimension from the classical Lie algebra. This is illustrated by menas of the ortho

Edsel A. Ammons

A program to utilize the Tamm-Dancoff approximation, on the light-front, to solve relativistic quantum field theories, is presented. We present a well defined renormalization program for the Tamm-Dancoff approximation. This renormalization program utilizes a Minkowski space version of Wilson&#39;s renormalization group. We studied light-front $ϕ^{4}$ field t

Elbio Dagotto, Alexander Nazarenko, Adriana Moreo

A theory for the high temperature superconductors is proposed. Holes are spin-1/2, charge e, quasiparticles strongly dressed by spin fluctuations. Based on their dispersion, it is claimed that the experimentally observed van Hove singularities of the cuprates are likely originated by antiferromagnetic (AF) correlations. From the two carriers problem in the 2

M. A. Moore, T. Blum J. P. Doherty, M. Marsili, J-P. Bouchaud

It is shown that the mode-coupling equations for the strong-coupling limit of the KPZ equation have a solution for d>4 such that the dynamic exponent z is 2 (with possible logarithmic corrections) and that there is a delta function term in the height correlation function <h(k,w)h^*(k,w)> = (A/k^{d+4-z}) \delta(w/k^z) where the amplitude A vanishes as d -> 4.

H. Aratyn, E. Nissimov, S. Pacheva, A. H. Zimerman

Toda lattice hierarchy and the associated matrix formulation of the $2M$-boson KP hierarchies provide a framework for the Drinfeld-Sokolov reduction scheme realized through Hamiltonian action within the second KP Poisson bracket. By working with free currents, which abelianize the second KP Hamiltonian structure, we are able to obtain an unified formalism fo

Jens Hoppe

$M$-dimensional extended objects $Σ$ can be described by projecting a Diff $Σ$ invariant Hamiltonian of time-independent Hamiltonian density {\cal H} onto the Diff $Σ$- singlet sector, which after Hamiltonian reduction, using {\cal H} itself for one of the gauge-fixing conditions, results in a non-local description that may enable one to extend the non-local

C. J. Benesh, J. L. Friar

We calculate the lowest-order contribution to the cross section for simultaneous excitation of projectile and target nuclei in relativistic heavy ion collisions. This process is, to leading order, non-classical and adds incoherently to the well-studied semi-classical Weizsäcker-Williams cross section. While the leading contribution to the cross section is do

M. Baldo, G. F. Burgio, A. Rapisarda

The Vlasov-Nordheim equation is solved numerically on a lattice for nuclear matter in two dimensions. We discuss the reliability of the model at normal density and then study the response of the system to small perturbations. We find deterministic chaos inside the spinodal zone where fragment formation occurs. We discuss in detail the dynamical features of t

Mihai Visinescu

The generalized Killing equations and the symmetries of Taub-NUT spinning space are investigated. For spinless particles the Runge-Lenz vector defines a constant of motion directly, whereas for spinning particles it now requires a non-trivial contribution from spin. The generalized Runge-Lenz vector for spinning Taub-NUT space is completely evaluated.

J. P. Gauntlett, J. A. Harvey

We discuss the predictions of S-duality for the monopole spectrum of four-dimensional heterotic string theory resulting from toroidal compactification. We discuss in detail the spectrum of &#34;H-monopoles&#34;, states that are magnetically charged with respect to the U(1) groups arising from the dimensional reduction of the ten dimensional antisymmetric ten

Andrei Johansen

We study a supersymmetric theory twisted on a Kähler four manifold $M=Σ_1 \times Σ_2 ,$ where $Σ_{1,2}$ are 2D Riemann surfaces. We demonstrate that it possesses a &#34;left-moving&#34; conformal stress tensor on $Σ_1$ ($Σ_2$) in a BRST cohomology, which generates the Virasoro algebra with the conventional commutation relations. The central charge of the Vir

M. Chu, P. Goddard

The quantisation of the Wess-Zumino-Witten model on a circle is discussed in the case of $SU(N)$ at level $k$. The quantum commutation of the chiral vertex operators is described by an exchange relation with a braiding matrix, $Q$. Using quantum consistency conditions, the braiding matrix is found explicitly in the fundamental representation. This matrix is

Cyril FURTLEHNER, Stéphane OUVRY

Motivated by topological bidimensional quantum models for distinguishable particles, and by Haldane&#39;s definition of mutual statistics for different species of particles, we propose a new class of one-dimensional $1/r_{ij}^2$ Calogero model with coupling constants $g_{ij}$ depending on the labels of the particles. We solve the groundstate problem, and sho

Ken Intriligator

We discuss integrating out matter fields and integrating in matter fields in four dimensional supersymmetric gauge theories. Highly nontrivial exact superpotentials can be easily obtained by starting from a known theory and integrating in matter.

A. Brandhuber, O. Moritsch, M. W. de Oliveira, O. Piguet

We reconsider the algebraic BRS renormalization of Witten&#39;s topological Yang-Mills field theory by making use of a vector supersymmetry Ward identity which improves the finiteness properties of the model. The vector supersymmetric structure is a common feature of several topological theories. The most general local counterterm is determined and is shown

A. Mikovic

We investigate the semiclassical limit and quantum corrections to the metric in a unitary quantum gravity formulation of the CGHS 2d dilaton gravity model. A new method for calculating the back-reaction effects has been introduced, as an expansion of the effective metric in powers of the matter energy-momentum tensor. In the semiclassical limit the quantum c

N. S. Manton, M. K. Murray

We discuss the spectral curves and rational maps associated with $SU(2)$ Bogomolny monopoles of arbitrary charge $k$. We describe the effect on the rational maps of inverting monopoles in the plane with respect to which the rational maps are defined, and discuss the monopoles invariant under such inversion. We define the strongly centred monopoles, and show

Andreas Vogt

The QCD treatment of the photon structure beyond the leading order is discussed with emphasis on a proper choice of the factorization scheme and/or the boundary conditions. Recent parametrizations of the photon&#39;s parton content are examined and compared. The sensitivity of the photon structure function on the QCD scale parameter is reconsidered.

M. A. Doncheski, S. Godfrey

We study leptoquark production using polarized $eγ$ colliders for the center of mass energies $\sqrt s=500$~GeV and 1~TeV. We show that using polarization asymmetries the ten different types of leptoquarks listed by Buchmüller, Rückl and Wyler can be distinquished from one another for leptoquark masses essentially up to the kinematic limit of the respective

Peter Arnold

Talk presented at the NATO Advanced Workshop on Electroweak Physics and the Early Universe: Sintra, Portugal, 1994. I summarize work done with Larry Yaffe on applying $ε$ expansion techniques to the electroweak phase transition.

J. Keppler, H. M. Hofmann

We start from an MIT-bag model calculation which provides information about the constituent quark distributions in the nucleon. The constituent quarks, however, are themselves considered as complex objects whose partonic substructure is resolved in deep inelastic scattering. This gives rise to structure functions of the constituent quarks which, in the unpol

Jes Madsen

An ansatz for the curvature contribution to the density of states for massive quarks in a bag is given and shown to reproduce exact mode-filling calculations. A mass-formula for spherical lumps of 3-flavor quark matter is derived self-consistently from an asymptotic expansion within the MIT bag model, taking into account bulk, surface, and curvature contribu

Scott Chapman

New terms are derived for the three-dimensional effective action of the static modes of pure gauge SU(N) at high temperature. In previous works, effective vertices have been obtained by evaluating diagrams involving 2, 3 or 4 external static gluons with one internal nonstatic loop. I take a somewhat different approach by making a covariant derivative expansi

Wei-Shu Hou, Ern-Bin Tsai, Chao-Qiang Geng, Paul Turcotte

Allowing for realistic uncertainties in input parameters, we demonstrate that the present CLEO limit of $5.4\times 10^{-4}$ for inclusive $b\to sγ$ decay does not yet fully exclude the $t\to bH^+$ decay possibility in supersymmetric type of two Higgs doublet models. Combined with direct search for $t\to bH^+$ via $H^+\to τ^+ν$ at the Tevatron, we conclude th

Alexander Reznikov

I prove the Bloch conjecture:all secondary characteristic classes of flat bundles over complex projective varietes are torsion, except the first.

Jian Ping Lu

An external magnetic field is found to have strong effects on the electronic structure of carbon nanotubes. A field-induced metal-insulator transition is predicted for all pure nanotubes. In a weak field, nanotubes exhibit both large diamagnetic and paramagnetic responses which depend on the field direction, the position of the Fermi energy, the helicity, an

M. C. Marchetti, V. M. Vinokur

We discuss the low-temperature dynamics of magnetic flux lines in high-temperature superconductors in the presence of a family of parallel twin planes that contain the $c$ axis. A current applied along the twin planes drives flux motion in the direction transverse to the planes and acts like an electric field applied to {\it one-dimensional} carriers in diso

S. L. A. de Queiroz, R. B. Stinchcombe

A transfer matrix scaling technique is developed for randomly diluted systems, and applied to the site-diluted Ising model on a square lattice in two dimensions. For each allowed disorder configuration between two adjacent columns, the contribution of the respective transfer matrix to the decay of correlations is considered only as far as the ratio of its tw

Scott Prevost, Mark Steedman

This paper presents a theory and a computational implementation for generating prosodically appropriate synthetic speech in response to database queries. Proper distinctions of contrast and emphasis are expressed in an intonation contour that is synthesized by rule under the control of a grammar, a discourse model, and a knowledge base. The theory is based o

M. Bruni, S. Matarrese, O. Pantano

We present results on the non-linear dynamics of inhomogeneous cosmological models with irrotational dust and a positive cosmological constant, considering, in particular, a wide class with vanishing magnetic Weyl tensor. For those patches of the universe that do not recollapse to a singularity we find a unique attractor, representing a de Sitter vacuum phas

Richard Hain, Jun Yang

In this paper we define real grassmann polylogarithms, which are real single valued analogues of the grassmann polylogarithms (or higher logarithms) defined by Hain and MacPherson. We prove the existence of all such real grassmann polylogs, at least generically. We also prove that the canonical choice of such an m-polylogarithm represents the Beilinson Chern

B. Holdom

A massive gauge boson coupling to the third family but not lighter families mixes with the $Z$. The $Z$ partial width to $b\overline{b}$ increases, the $τ$ asymmetry parameter increases, the invisible width of the $Z$ decreases, and $α_s(m_Z)$ decreases, all in a manner consistent with present data.

A. A. Tseytlin

We review known exact classical solutions in (bosonic) string theory. The main classes of solutions are `cosets&#39; (gauged WZW models), `plane wave&#39;-type backgrounds (admitting a covariantly constant null Killing vector) and `$F$-models&#39; (backgrounds with two null Killing vectors generalising the `fundamental string&#39; solution). The recently con

Jörg Brendle

We show that if the real line is the disjoint union of kappa meager sets such that every meager set is contained in a countable union of them, then kappa = omega_1. This answers a question addressed by J. Cichon. We also prove two theorems saying roughly that any attempt to produce the isomorphism type of the meager ideal in the Cohen real and the random rea