June 1992 arXiv papers — page 2

Ron Donagi

In this work we use the bigonal, trigonal and tetragonal constructions to describe the fibers of the Prym map P : R_{g} ---->A_{g-1} inthe cases when it is dominant, i.e. for g < 7. The most interesting cases are g = 5, where the fiber is a double cover of the Fano surface of lines on a cubic threefold, and g=6, where the map is generically finite (of degree

M. Garcia Perez, A. Gonzalez-Arroyo

We use the lattice cooling method to investigate the structure of some gauge fixed SU(2) Yang-Mills classical solutions of the euclidean equations of motion which are defined in the 3-torus with symmetric twisted boundary conditions.

T. Altherr, T. Grandou

We construct a quantum thermal field theory for scalar particles in the case of infinite statistics. The extension is provided by working out the Fock space realization of a &#34;quantum algebra&#34;, and by identifying the hamiltonian as the energy operator. We examine the perturbative behavior of this theory and in particular the possible extension of the

J. Russo, L. Susskind, L. Thorlacius

The formation and semi-classical evaporation of two-dimensional black holes is studied in an exactly solvable model. Above a certain threshold energy flux, collapsing matter forms a singularity inside an apparent horizon. As the black hole evaporates the apparent horizon recedes and meets the singularity in a finite proper time. The singularity emerges naked

Edward Witten

This lecture surveys a few loosely related topics, ranging from the scarcity of quantum field theories -- and the role that this has played, and still plays, in physics -- to paradoxes involving black holes in soluble two dimensional string theory and the question of whether naked singularities might be of even greater interest to string theorists than black

Rue-Ron Hsu, Green Huang, Wei-Fu Lin

Under the axisymmetry and under the invarance of simultaneous inversion of time and azimuthal angle, we show that the axionic Kerr black hole is the ${\it unique}$ stationary solution of the minimal coupling theory of gravity and the Kalb-Ramond field, which has a regular event horizon, is asymptotically flat and has a finite axion field strength at event ho

A. A. Tseytlin

We discuss some aspects of string cosmology with an emphasis on the role played by the dilaton. A cosmological scenario based on the assumption that all spatial dimensions are periodic so that winding modes play an important role is reviewed. A possibility of a transition from a `string phase&#39; to the `standard&#39; cosmology via a radiation dominated era

Clifford V. Johnson, Tim R. Morris, Peter L. White

We study further the rôle of the boundary operator $Ø_B$ for macroscopic loop length in the stable definition of 2D quantum gravity provided by the $[{\tilde P},Q]=Q$ formulation. The KdV flows are supplemented by an additional flow with respect to the boundary cosmological constant $σ$. We numerically study these flows for the $m=1$, $2$ and $3$ models, sol

Ernest Ma

The universality of $e-μ-τ$ interactions may only be an accidental approximate symmetry analogous to that of flavor SU(2) and SU(3). This was specifically realized by an extension of the standard model proposed in 1981. Two key predictions are that the $τ$ lifetime should be longer and that the $ρ$ parameter measured at the Z peak should have an additional n

J. L. Goity

The SU(3) breaking effects due to light quark masses on heavy meson masses, decay constants ($F_{D}, F_{D_{s}}$) and the form factor for semileptonic $\overline{B}\rightarrow D^{(\ast)} l\barν_{l}$ transitions are formulated in chiral perturbation theory, using a heavy meson effective Lagrangian and expanding in inverse powers of the heavy meson mass. To lea

Mark Hindmarsh

Semilocal defects are those formed in field theories with spontaneously broken symmetries, where the vacuum manifold $M$ is fibred by the action of the gauge group in a non-trivial way. Studied in this paper is the simplest such class of theories, in which $M\simeq S^{2N-1}$, fibred by the action of a local $U(1)$ symmetry. Despite $M$ having trivial homotop

J. M. Gelb, Waikwok Kwong, S. P. Rosen

We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron sc

J. R. Espinosa, M. Quirós, F. Zwirner

The basic tool for the study of the electroweak phase transition is $V_{eff} (ϕ,T)$, the one-loop finite-temperature effective potential, improved by all-loop resummations of the most important infrared contributions. In this paper we perform, as a first step towards a full analysis of the Standard Model case, a detailed study of the effective potential of t

Raman Sundrum, Stephen D. H. Hsu

We examine the effect of walking technicolor dynamics on the electroweak $S$ parameter and contrast it with the effect of QCD-like technicolor dynamics. Our main tools are the operator product expansion for the high-momentum behavior of the electroweak gauge boson vacuum polarizations and the analyticity of these polarizations which relate their low and high

Jacek Graczyk, Grzegorz Swiatek

Critical circle homeomorphisms have an invariant measure totally singular with respect to the Lebesgue measure. We prove that singularities of the invariant measure are of Holder type. The Hausdorff dimension of the invariant measure is less than 1 but greater than 0.

Rene Lafrance, Robert Myers

We report results of two investigations of the double-scaling equations for the unitary matrix models. First, the fixed area partition functions have all positive coefficients only for the first four critical points. This implies that the critical points at $k\ge5$ describe non-unitary continuum theories. Secondly, we examine a conjectured connection to bran

O. Aharony, J. Sonnenschein, S. Yankielowicz

We derive the BRST cohomology of the G/G topological model for the case of A^{(1)}_{N-1} . It is shown that at level k={p/q}-N the latter describes the (p,q) W_N minimal model coupled to $W_N$ gravity (plus some extra ``topological sectors&#34;).

M. Natsuume

It is shown that a renormalizable nonlinear sigma model gives rise to the effective string theory proposed by Polchinski and Strominger. In the presence of long string background, the model contains massive world-sheet degrees of freedom owing to the spontaneous breaking of conformal invariance.

Hitoshi Ikemori

We present a concise method to construct a BRST invariant action for the topological quantum field theories in the Batalin-Vilkovisky antifield formalism. The BV action that is a solution for the master equation is directly obtained by means of the extended forms that involve all the required ghosts and antifields. The BV actions for the non-abelian $BF$ the

Ernest Ma

If the quadratic divergence of the standard electroweak model and its local variation with mass scale are both assumed to be zero, then a modified one-loop calculation yields m_t = 117 GeV and m_H = 183 GeV. Such a scenario may be the result of an underlying theory to be revealed at a much higher mass scale.

H. Goldberg, M. T. Vaughn

We present a quantum mechanical model with an infinite number of (discrete) degrees of freedom, which can serve as a laboratory for multiparticle production in a collision. There is a cubic coupling between modes without, however, any problems associated with unstable ground states. The model is amenable to precise numerical calculations of nonperturbative 1

Robert H. Brandenberger, Anne-Christine Davis

If stable electroweak strings are copiously produced during the electroweak phase transition, they may contribute significantly to the presently observed baryon to entropy ratio of the Universe. This analysis establishes the feasibility of implementing an electroweak baryogenesis scenario without a first order phase transition.

Jean-Francois Mestre

We prove that there exist infinitely many elliptic curves over \Q with given modular invariant, and rank >=2. Furthermore, there exist infinitely many elliptic curves over $\Q$ with invariant equal at 0 (resp. 1728) and rank >=6 (resp. >=4).

Jean-Francois Mestre

We prove the existence of infinitely many real and imaginary fields whose 5-rank of the class group is >=3.

R. G. Leigh

We discuss aspects of poor infrared behaviour of the perturbation expansion for the effective potential of the Higgs mode near the electroweak phase transition, and enlarge on the discovery that higher order effects weaken the transition. In addition, we outline our recent attempts at understanding the dynamics involved in the propagation of bubbles formed i

R. Sekhar Chivukula, M. Dugan, M. Golden

The chiral Lagrangian for Goldstone boson scattering is a power series expansion in numbers of derivatives. Each successive term is suppressed by powers of a scale, $Λ_χ$, which must be less than of order $4πf/\sqrt{N}$ where $f$ is the Goldstone boson decay constant and $N$ is the number of flavors. The chiral expansion therefore breaks down at or below $4

J. L. Hewett, T. G. Rizzo

We examine the possibility of using rare, 3-body decays of a new neutral gauge boson, \ztwo, to probe its gauge couplings at hadron colliders. Specifically, we study the decays $\ztwo\to W\ellν$ and $\ztwo\to Zν\barν$ and find that much knowledge of the \ztwo\ properties can be obtained from these processes. In particular, these decay modes can yield valuabl

S. Dalley, C. V. Johnson, T. R. Morris, A. Watterstam

The KdV and modified KdV integrable hierarchies are shown to be different descriptions of the same 2D gravitational system -- open-closed string theory. Non-perturbative solutions of the multi-critical unitary matrix models map to non-singular solutions of the `renormalisation group&#39; equation for the string susceptibility, $[\tilde{P},Q]=Q$. We also demo

Viqar Husain

The self-duality equations for the Riemann tensor are studied using the Ashtekar Hamiltonian formulation for general relativity. These equations may be written as dynamical equations for three divergence free vector fields on a three dimensional surface in the spacetime. A simplified form of these equations, describing metrics with a one Killing field symmet

W. A. Sabra

We examine the relation between Polyakov&#39;s formulation of two dimensional supergravity and gauged Wess-Zumino-Novikov-Witten models.

Tetsuo Deguchi, Yasuhiro Akutsu

We present formulas for the Clebsch-Gordan coefficients and the Racah coefficients for the root of unity representations ($N$-dimensional representations with $q^{2N}=1$) of $U_q(sl(2))$. We discuss colored vertex models and colored IRF (Interaction Round a Face) models from the color representations of $U_q(sl(2))$. We construct invariants of trivalent colo

Martin-D. Lacasse, Jorge Vinals, Martin Grant

The dynamical critical exponent of the two-dimensional spin-flip Ising model is evaluated by a Monte Carlo renormalization group method involving a transformation in time. The results agree very well with a finite-size scaling analysis performed on the same data. The value of $z = 2.13 \pm 0.01$ is obtained, which is consistent with most recent estimates.

Mark Srednicki

Phenomenological and formal restrictions on the evolution of pure into mixed states are discussed. In particular, it is argued that, if energy is conserved, loss of purity is incompatible with the weakest possible form of Lorentz covariance.

Michael Dine

It now seems plausible that the observed baryon asymmetry may have been produced at the electroweak phase transition. We review the considerations which lead to this conclusion, focusing on the obstacles to making reliable estimates. These arise from incomplete knowledge of baryon-violating rates near the phase transition, our limited understanding of the ph

T. Banks, M. O&#39;Loughlin

We argue that the paradoxes associated with infinitely degenerate states, which plague relic particle scenarios for the endpoint of black hole evaporation, may be absent when the relics are horned particles. Most of our arguments are based on simple observations about the classical geometry of extremal dilaton black holes, but at a crucial point we are force

E. Abdalla, M. C. B. Abdalla, D. Dalmazi

We compute correlation functions in $N=2$ non critical superstrings on the sphere. Our calculations are restrained to the ($s=0$) bulk amplitudes. We show that the four point function factorizes as a consequence of the non-critical kinematics, but differently from the $N=0,1$ cases no extra discrete state appears in the $\hat c\to 1^-$ limit.

H. Dorn, H. -J. Otto

We construct a Goulian-Li-type continuation in the number of insertions of the cosmological constant operator which is no longer restricted to one dimensional target space. The method is applied to the calculation of the three-point and a special four-point correlation function. Various aspects of the emerging analytical structure are discussed.

F. del Aguila, B. Alles, Ll. Ametller, A. Grau

If a new $Z&#39;$ is discovered with a mass $\sim 1 \ TeV$ at LHC/SSC, its (rare) decays into two charged leptons plus missing transverse energy will probe the $Z&#39;$ coupling to the lepton doublet $(ν,e)_L$ and to $W^+W^-$, allowing further discrimination among extended electroweak models.

Valery Alexeev

Varieties with log terminal and log canonical singularities are considered in the Minimal Model Program, see \cite{...} for introduction. In \cite{shokurov:hyp} it was conjectured that many of the interesting sets, associated with these varieties have something in common: they satisfy the ascending chain condition, which means that every increasing chain of

Yun-Gang Ye

This is a revised version of the paper submitted before.

Patrick Dorey, Francesco Ravanini

We propose a class of purely elastic scattering theories generalising the staircase model of Al. B. Zamolodchikov, based on the affine Toda field theories for simply-laced Lie algebras g=A,D,E at suitable complex values of their coupling constants. Considering their Thermodynamic Bethe Ansatz equations, we give analytic arguments in support of a conjectured

Alok Kumar

An O($\tilde{d}$, $\tilde{d}$) transformation is given which relates ungauged string actions to the gauged ones for a large class of models discussed recently by Giveon and Rocek. Interestingly, the transformation is background independent and has a unique matrix representation in a given space-time dimension.

Ramon Munoz-Tapia

We apply the method of differential renormalization to two and three dimensional abelian gauge theories. The method is especially well suited for these theories as the problems of defining the antisymmetric tensor are avoided and the calculus involved is impressively simple. The topological and dynamical photon masses are obtained.

L. Brink, T. H. Hansson, M. A. Vasiliev

We solve the N-body Calogero problem, \ie N particles in 1 dimension subject to a two-body interaction of the form $\half \sum_{i,j}[ (x_i - x_j)^2 + g/ {(x_i - x_j)^2}]$, by constructing annihilation and creation operators of the form $ a_i^\mp =\frac 1 {\sqrt 2} (x _i \pm i\hat{p}_i )$, where $\hat{p}_i$ is a modified momentum operator obeying %!!!!!!! Hei

S. Kelley, J. Lopez, D. Nanopoulos, H. Pois

We discuss several aspects of state-of-the-art calculations of radiative electroweak symmetry breaking in supergravity models. These models have a five-dimensional parameter space in contrast with the 21-dimensional one of the MSSM. We examine the Higgs one-loop effective potential $V_1=V_0+ΔV$, in particular how its renormalization-scale ($Q$) independence

Frank Close, Zhenping Li

We show how heavy quark effective theory, including 1/M corrections, may be matched onto dynamical quark models by making a specific choice of K,m and v in the p=mv+K expansion. We note that Wigner rotations of heavy quark spins arise at $O(p^2/m^2)$ in non-relativistic models but at $O(Λ_{QCD}/M_Q)$ or O(velocity-transfer) in HQET and so are necessary for a

John Preskill

I analyze the interplay of gauge and global symmetries in the theory of topological defects. In a two-dimensional model in which both gauge symmetries and {\it exact} global symmetries are spontaneously broken, stable vortices may fail to exist even though magnetic flux is topologically conserved. Following Vachaspati and Achúcarro, I formulate the condition

Yasuji Ono, Daijiro Suematsu

We examine the time variation problem of solar neutrinos in the spin-flavour precession mechanism taking into account the $ν_e$-$ν_μ$ mixing. The models with the small and large mixing angle are studied. It shows that the models which realize $m_{ν_eν_e} \sim m_{ν_μν_μ} \ll m_{ν_eν_μ}$ and $m_{ν_eν_e} \sim m_{ν_μν_μ} {^>_\sim} m_{ν_eν_μ}$ seem to have prefer

C. F. Baillie, D. A. Johnston

We perform Monte Carlo simulations using the Wolff cluster algorithm of the XY model on both fixed and dynamical phi-cubed graphs (i.e. without and with coupling to two-dimensional quantum gravity). We compare the numerical results with the theoretical expectation that the phase transition remains of KT type when the XY model is coupled to gravity. We also e

D. B. Kaplan

A method for simulating chiral gauge theories on the lattice is proposed, involving zeromodes on a topological defect. Lattice doublers may be decoupled in a gauge invariant manner, and flavor anomalies can be directly observed on a finite lattice. (Requires harvmac)

Elihu Abrahams, Alexander Balatsky, J. R. Schrieffer, Philip B. Allen

A class of singlet superconductors with a gap function $\Delta({\bf k}, \omega_n)$ which is {\it odd} in both momentum and Matsubara frequency was proposed recently \cite{ba}. To show an instability in the {\it odd} gap channel, a model phonon propagator was used with the $p$-wave interaction strength larger than the $s$-wave. We argue that the positive scat

Konstadinos Sfetsos

Using the conformal invariance of the $SL(2,R)\otimes SO(1,1)^{d-2}/SO(1,1)$ coset models we calculate the conformally exact metric and dilaton, to all orders in the $1/k$ expansion. We consider both vector and axial gauging. We find that these cosets represent two different space--time geometries: ($2d$ black hole)$\otimes \IR^{d-2}$ for the vector gauging

Luca Mezincescu, Rafael I. Nepomechie

We show that the quantum-algebra-invariant open spin chains associated with the affine Lie algebras $A^{(1)}_n$ for $n>1$ are integrable. The argument, which applies to a large class of other quantum-algebra-invariant chains, does not require that the corresponding $R$ matrix have crossing symmetry.

Joseph A. Minahan, Alexios P. Polychronakos

We show that a class of models for particles with internal degrees of freedom are integrable. These systems are basically generalizations of the models of Calogero and Sutherland. The proofs of integrability are based on a recently developed exchange operator formalism. We calculate the wave-functions for the Calogero-like models and find the ground-state wa

Howard J. Schnitzer

The 1/N expansion for the O(N) vector model in four dimensions is reconsidered. It is emphasized that the effective potential for this model becomes everywhere complex just at the critical point, which signals an unstable vacuum. Thus a critical O(N) vector model cannot be consistently defined in the 1/N expansion for four-dimensions, which makes the existen

R. B. Mann

A very general class of Lagrangians which couple scalar fields to gravitation and matter in two spacetime dimensions is investigated. It is shown that a vector field exists along whose flow lines the stress-energy tensor is conserved, regardless of whether or not the equations of motion are satisfied or if any Killing vectors exist. Conditions necessary for

E. Elizalde, S. D. Odintsov

Two-dimensional Maxwell-dilaton quantum gravity, which covers a large family of the actions for two-dimensional gravity (in particular, string-inspired models) is investigated. Charged black holes which appear in the theory are briefly discussed. The one-loop divergences in the linear covariant gauges are calculated. It is shown that for some choices of the

Y. Imamura, M. Sakamoto, T. Sasada, M. Tabuse

We study symmetries between untwisted and twisted strings on asymmetric orbifolds. We present a list of asymmetric orbifold models to possess intertwining currents which convert untwisted string states to twisted ones, and vice versa. We also present a list of heterotic strings on asymmetric orbifolds with supersymmetry between untwisted and twisted string s

A. LeClair, D. Nemeschansky, N. P. Warner

S-matrices for integrable perturbations of $N=2$ superconformal field theories are studied. The models we consider correspond to perturbations of the coset theory $G_k \times H_{g-h} /H_{k+g-h} $. The perturbed models are closely related to $\hat G$-affine Toda theories with a background charge tuned to $H$. Using the quantum group restriction of the affine

A. G. Cohen, D. B. Kaplan, A. E. Nelson

We examine a recent claim that Debye screening will affect the charge transport mechanism of anomalous electroweak baryogenesis. We show that the effects of gauge charge screening do not affect the baryon number produced during a first order electroweak phase transition. (Requires harvmac.tex)

Karl Jansen

A recent proposal by Kaplan for a chiral gauge theory on the lattice is tested with background gauge fields. The spectrum of the finite lattice Hamiltonian is calculated and the existence of a chiral fermion is demonstrated. Lattice doublers are found to decouple. The flavor anomalies, which are in agreement with the continuum anomaly relation, are obeserved

Fernando Martinez-Moras, Eduardo Ramos

Classical $W$-algebras in higher dimensions are constructed. This is achieved by generalizing the classical Gel&#39;fand-Dickey brackets to the commutative limit of the ring of classical pseudodifferential operators in arbitrary dimension. These $W$-algebras are the Poisson structures associated with a higher dimensional version of the Khokhlov-Zabolotskaya

M. Leblanc, G. Lozano, H. Min

We study the nonrelativistic limit of the $N=2$ supersymmetric Chern-Simons matter system. We show that in addition to Galilean invariance the model admits a set of symmetries generated by fermionic charges, which can be interpreted as an {\it extended Galilean supersymmetry }. The system also possesses a hidden conformal invariance and then the full group o

Gerald Dunne, Nuria Rius

We show that there is a very simple relationship between differential and dimensional renormalization of low-order Feynman graphs in renormalizable massless quantum field theories. The beauty of the differential approach is that it achieves the same finite results as dimensional renormalization without the need to modify the space time dimension.

Boris Dubrovin

Integrability of equations of topological-antitopological fusion (being proposed by Cecotti and Vafa) describing ground state metric on given 2D topological field theory (TFT) model, is proved. For massive TFT models these equations are reduced to a universal form (being independent on the given TFT model) by gauge transformations. For massive perturbations

J. S. Dowker, Peter Chang

Quantum field theory is discussed in Möbius corner kaleidoscopes using the method of images. The vacuum average of the stress-energy tensor of a free field is derived and is shown to be a simple sum of straight cosmic string expressions, the strings running along the edges of the corners. It does not seem possible to set up a spin-half theory easily.

Edouard Brézin, Jean Zinn-Justin

Matrix models of 2D quantum gravity are either exactly solvable for matter of central charge $ c\leq 1, $ or not understood. It would be useful to devise an approximate scheme which would be reasonable for the known cases and could be carried to the unsolved cases in order to achieve at least a qualitative understanding of the properties of the models. The d

Atsuo Kuniba, Tomoki Nakanishi

We propose a system of functional relations having a universal form connected to the $U_q(X^{(1)}_r)$ Bethe ansatz equation. Based on the analysis of it, we conjecture a new sum formula for the Rogers dilogarithm function in terms of the scaling dimensions of the $X^{(1)}_r$ parafermion conformal field theory.

Antti J. Niemi, O. Tirkkonen

We argue, that for a general class of nontrivial bosonic theories the path integral can be related to an equivariant generalization of conventional characteristic classes.

L. Begin, P. Mathieu, M. A. Walton

A closed and explicit formula for all $\su{(3)}_k$ fusion coefficients is presented which, in the limit $k \rightarrow \infty$, turns into a simple and compact expression for the $su(3)$ tensor product coefficients. The derivation is based on a new diagrammatic method which gives directly both tensor product and fusion coefficients.

C. M. Hull, L. Palacios

Many $W$-algebras (e.g. the $W_N$ algebras) are consistent for all values of the central charge except for a discrete set of exceptional values. We show that such algebras can be contracted to new consistent degenerate algebras at these exceptional values of the central charge.

Haim Goldberg

I present an extension to arbitrary N of a previously proposed field theoretic model, in which unitary amplitudes for $1->8$ processes were obtained. The Born amplitude in this extension has the behavior $A(1->N)^{tree}\ =\ g^{N-1}\ N!$ expected in a bosonic field theory. Unitarity is violated when $|A(1->N)|>1$, or when $N>\N_crit\simeq e/g.$ Numerical solu

C. F. Baillie, D. A. Johnston

We investigate the crumpling transition for a dynamically triangulated random surface embedded in two dimensions using an effective model in which the disordering effect of the $X$ variables on the correlations of the normals is replaced by a long-range ``antiferromagnetic&#39;&#39; term. We compare the results from a Monte Carlo simulation with those obtain

Kanehisa Takasaki

Small errors are corrected

Peter Schupp, Paul Watts, Bruno Zumino

An exterior derivative, inner derivation, and Lie derivative are introduced on the quantum group $GL_{q}(N)$. $SL_{q}(N)$ is then found by constructing matrices with determinant unity, and the induced calculus is found.

D. Z. Freedman, K. Johnson, R. Munoz-Tapia, X. Vilasis-Cardona

Explicit divergences and counterterms do not appear in the differential renormalization method, but they are concealed in the neglected surface terms in the formal partial integration procedure used. A systematic real space cutoff procedure for massless $ϕ^4$ theory is therefore studied in order to test the method and its compatibility with unitarity. Throug

Nigel J. Kalton, P. Wojtaszczyk

We are interested in the question when a Banach space $X$ with an unconditional basis is isomorphic (as a Banach space) to an order-continuous nonatomic Banach lattice. We show that this is the case if and only if $X$ is isomorphic as a Banach space with $X(\ell_2)$. This and results of J. Bourgain are used to show that spaces $H_1(\bold T^n)$ are not isomor

A. Cappelli, C. A. Trugenberger, G. R. Zemba

Free planar electrons in a uniform magnetic field are shown to possess the symmetry of area-preserving diffeomorphisms ($W$-infinity algebra). Intuitively, this is a consequence of gauge invariance, which forces dynamics to depend only on the flux. The infinity of generators of this symmetry act within each Landau level, which is infinite-dimensional in the

E. Bergshoeff, L. A. J London, P. K. Townsend

We generalize to p-dimensional extended objects and type II superstrings a recently proposed Green-Schwarz type I superstring action in which the tension $T$ emerges as an integration constant of the equations of motion. The action is spacetime scale-invariant but its equations of motion are equivalent to those of the standard super p-brane for $T\ne 0$ and

J. S. Dowker, A. Wolski

A finite-dimensional su($N$) Lie algebra equation is discussed that in the infinite $N$ limit (giving the area preserving diffeomorphism group) tends to the two-dimensional, inviscid vorticity equation on the torus. The equation is numerically integrated, for various values of $N$, and the time evolution of an (interpolated) stream function is compared with

Antonio Masiero, Antonio Riotto

We propose a new mechanism for late cosmological baryon asymmetry in models with first order electroweak phase transition. Lepton asymmetry arises through the decay of particles produced out of equilbrium in bubble collisions and is converted into baryon asymmetry by sphalerons. Supersymmetric models with explicitly broken R-parity may provide a suiatble fra

S. P. de Alwis

In a previous paper it was shown that the quantum consistency conditions for the dilaton-gravity theory of Callan et al., imply that the cosmological constant term undergoes a dilaton dependent renormalization, in such a manner that the theory can be written as a Liouville-like theory. In this paper we discuss the physical interpretation of the solutions of

Peter Schupp, Paul Watts, Bruno Zumino

The algebra dual to Woronowicz&#39;s deformation of the 2-\-di\-men\-sion\-al Euclidean group is constructed. The same algebra is obtained from $SU_{q}(2)$ via contraction on both the group and algebra levels.

Amit Giveon

A truncation of string field theory is compared with the duality invariant effective action of $D=4, N=4$ heterotic strings to cubic order. The three string vertex must satisfy a set of compatibility conditions. Any cyclic three string vertex is compatible with the $D=4, N=4$ effective field theory. The effective actions may be useful in understanding the no

R. B. Mann, S. F. Ross

The properties of a string-inspired two-dimensional theory of gravity are studied. The post-Newtonian and weak-field approximations, `stellar&#39; structure and cosmological solutions of this theory are developed. Some qualitative similarities to general relativity are found, but there are important differences.

Daniel S. Freed

There is a large mathematical literature on classical mechanics and field theory, especially on the relationship to symplectic geometry. One might think that the classical Chern-Simons theory, which is topological and so has vanishing hamiltonian, is completely trivial. However, this theory exhibits interesting geometry that is usually absent from ordinary f

Laurent Baulieu

We consider the BRST and superconformal properties of the ghost action of 2-D supergravity. Using the background spin structure on the worldsheet, we show that this action can be transformed by canonical field transformations to reach other conformal models such as the 2-D topological gravity or the chiral models for which the gauge variation of the action r

S. Mignemi, N. R. Stewart

Campbell et al. demonstrated the existence of axion ``hair&#39;&#39; for Kerr black holes due to the non-trivial Lorentz Chern-Simons term and calculated it explicitly for the case of slow rotation. Here we consider the dilaton coupling to the axion field strength, consistent with low energy string theory and calculate the dilaton ``hair&#39;&#39; arising fr

Myron Bander, Hector Rubinstein

Composite hadronic states exhibit interesting properties in the presence of very intense magnetic fields, such as those conjectured to exist in the vicinity of certain astrophysical objects. We discuss three scenarios. (i) The presence of vector particles with anomalous magnetic moment couplings to scalar particles, induces an instability of the vacuum. (ii)

Debajyoti Choudhury

The problem of generating large transition magnetic moments for nearly massless neutrinos in a truly three--generation case is discussed. A model to achieve the same by exploiting an octahedral symmetry is presented. The scheme also accomodates a radiatively generated mass of $17\:keV$ for a pseudo--Dirac neutrino that decays rapidly through the Majoron chan

Paul Langacker, Jiang Liu

With the standard electroweak interactions, the lowest-order coherent forward scattering amplitudes of neutrinos in a CP symmetric medium (such as the early universe) are zero, and the index of refraction of a propagating neutrino can only arise from the expansion of gauge boson propagators, from radiative corrections, and from new physics interactions. Moti

Miriam Leurer

Virtual leptoquarks could be detected at HERA through some nonstandard effects. Here we explore the possibility that virtual leptoquarks could be discovered via $e u --> e c$ scattering, assuming integrated luminosity of 200 pb$^{-1}$ and charm identification efficiency of 1%. We study the implications of low energy data for the leptoquarks couplings and fin

T. A. DeGrand, M. W. Hecht

This is a second paper describing the calculation of spectroscopy for orbitally excited states from lattice simulations of Quantum Chromodynamics. New features include higher statistics for P-wave systems and first results for the spectroscopy of D-wave mesons and baryons, for relatively heavy quark masses. We parameterize the Coulomb gauge wave functions fo

Maarten Golterman, Don Petcher, Elena Rivas

The model proposed by Eichten and Preskill for obtaining theories with chiral fermions from the lattice is shown to undergo spontaneous symmetry breaking. In addition, the fermions appear to be Dirac-like everywhere in the phase diagram with no room for undoubled Weyl fermions. The phase diagram of a closely related Higgs-Yukawa model is similar to that of t

D. S. Henty, R. D. Kenway

We present a technique which permits the calculation of two-point functions of operators containing one heavy quark and an arbitrary number of light quarks as analytic functions of the heavy-quark mass. It is based on the standard Jacobi linear solver used for the calculation of quark propagators. Results for the heavy-light pseudoscalar and vector meson mas

R. Brower, P. Tamayo

The Fortuin-Kasteleyn mapping between the Ising model and the site-bond correlated percolation model is shown to be only one of an infinite class of exact mappings. These new cluster representations are a result of &#34;renormalized&#34; percolation rules correlated to entire blocks of spins. For example these rules allow for percolation on &#34;virtual&#34;

N. Mohan Kumar

We classify smooth surfaces whose higher cohomologies of i-forms for all i vanish. We show that if such a surface is not affine, then it has essentially two possibilities.

Andreas Ruffing, Thomas Deck, Martin Schlichenmaier

The propagation differential for bosonic strings on a complex torus with three symmetric punctures is investigated. We study deformation aspects between two point and three point differentials as well as the behaviour of the corresponding Krichever-Novikov algebras. The structure constants are calculated and from this we derive a central extension of the Kri

Nobuyoshi Ohta

Minor misprints corrected.

Mary K. Gaillard

Strong rescattering corrections to one-loop contributions to the parameters of the standard electroweak model are considered.