October 1993 arXiv papers — page 5

Frank Cuypers, Geert Jan van Oldenborgh, Reinhold Rückl

Linear collider designs are optimized for \ep\ collisions. However, from the physics point of view, \lc s may also be advantageously operated in an \ee, \eg\ or \pp\ mode. These options, which have not been available up to now, will provide unique tests of the \sm\ and of physics beyond it. As an example, we review the prospects for discovering and studying

Torbjörn Sjöstrand, Valery A. Khoze

In the hadronic decay mode of a pair of W bosons, $\text{e}~+\text{e}~- \to \text{W}~+ \text{W}~- \to \text{q}_1 \overline{\text{q}}_2 \text{q}_3 \overline{\text{q}}_4$, QCD interference effects can mix up the two colour singlets $\text{q}_1 \overline{\text{q}}_2$ and $\text{q}_3 \overline{\text{q}}_4$, i.e. produce hadrons that cannot be uniquely assigned t

P. Olesen

We give plausibility arguments for the existence of a $W$--dressed electroweak string for the \ws ~model with $þ_W = 0$. This string is a $Z$--string which in the core has a finite energy contribution from $W$--condensation induced by the anomalous magnetic moment in the \ym field. The solution which has minimum energy at $r=0$ interpolates between the unbro

Makoto Oka

A lecture given at the International School Seminar on {\sl Hadrons and Nuclei from QCD}, Tsuruga-Vladivostok-Sapporo, August-September, 1993. A realistic hyperon ($Y$)-nucleon ($N$) interaction based on the quark model and the one-boson-exchange potential is constructed. The Nijmegen potential model D with the SU(3) flavor symmetry is modified with a quark

Ping Ao, David J. Thouless

We have performed a theoretical study of the effects of pinning potential and dissipation on vortex tunneling in superconductors. Analytical results are obtained in various limits relevant to experiment. In general we have found that pinning and dissipation tend to suppress the effect of the vortex velocity dependent part of the Magnus force on vortex tunnel

E. Choi, H. -T. S. Lihn, H. D. Drew, T. C. Hsu

The magneto-optical activity of superconducting ${\rm YBa}_{2}{\rm Cu}_{3}{\rm O}_{7}$ observed by Karrai {\it et al.} is not present in many commonly employed models of vortex dynamics. Here we propose a simple, unifying picture for the frequency dependent magneto-optic response of type-II superconductors at low temperatures. We bring together Kohn's th

F. F. Assaad, W. Hanke, D. J. Scalapino

Based on extensions of the grand-canonical Quantum Monte-Carlo algorithm to incorporate magnetic fields, we provide numerical data confirming the existence of a Kosterlitz-Thouless transition in the attractive Hubbard model. Here, we calculate the temperature derivative of the superfluid density, to pin down the transition. Away from half-band filling, the a

Thomas Blum, Yonathan Shapir

Sums of walks for charged particles (e.g. Hofstadter electrons) on a square lattice in the presence of a magnetic field are evaluated. Returning loops are systematically added to directed paths to obtain the unrestricted propagators. Expressions are obtained for special values of the magnetic flux-per-plaquette commensurate with the flux quantum. For commens

R. K. Schaefer, Q. Shafi

We explore constraints on inflationary models employing data on large scale structure mainly from COBE temperature anisotropies and IRAS selected galaxy surveys, taking care not to apply linear perturbation theory to data in the non-linear regime. In models where the tensor contribution to the COBE signal is negligible, we find the spectral index of density

T. J. Martin, F. R. Pearce, P. A. Thomas

We present a practical guide to Smoothed Particle Hydrodynamics (\SPH) and its application to astrophysical problems. Although remarkably robust, \SPH\ must be used with care if the results are to be meaningful since the accuracy of \SPH\ is sensitive to the arrangement of the particles and the form of the smoothing kernel. In particular, the initial conditi

F. R. Pearce, P. A. Thomas, H. M. P. Couchman

Several simple mergers between model galaxy clusters containing a mixture of gas and dark matter are examined, testing the coupling of the gas to the underlying collisionless material. The gas is shocked, irreversibly dissipating the energy fed into it by the collisionless component and forms a resolved constant-density core. For the dark matter, however, ad

T. Buchert, A. G. Weiss

The Lagrangian theory of gravitational instability of homogeneous-isotropic Friedman-Lemaitre cosmogonies investigated and solved in the series of papers by Buchert (1989), (1992), Buchert & Ehlers (1993), Buchert (1993a,b), Ehlers & Buchert (1993), is illustrated. The third-order solution of this theory for generic initial conditions is presented and realiz

Marco Matone

An Ansatz for the Poincaré metric on compact Riemann surfaces is proposed. This implies that the Liouville equation reduces to an equation resembling a non chiral analogous of the higher genus relationships (KP equation) arising in the framework of Schottky's problem solution. This approach connects uniformization (Fuchsian groups) and moduli space theor

John Ellis, Marek Karliner

We review the theory and phenomenology of deep inelastic polarized lepton-nucleon scattering in the light of recent data with a deuteron target from the SMC at CERN and a Helium 3 target from the E142 experiment at SLAC. After including higher-order perturbative QCD corrections, mass corrections and updated estimates of higher-twist effects, we find good agr

T. Inui, T. Ichihara, Y. Mimura, N. Sakai

Cosmological baryon asymmetry B is studied in supersymmetric standard models, assuming the electroweak reprocessing of B and L. Only when the soft supersymmetry breaking is taken into account, B is proportional to the primordial B-L in the supersymmetric standard models. The ratio $B/(B-L)$ is found to be about one percent less than the nonsupersymmetric cas

B. R. Iyer, C. V. Vishveshwara

The phenomenon of gyroscopic precession is studied within the framework of Frenet-Serret formalism adapted to quasi-Killing trajectories. Its relation to the congruence vorticity is highlighted with particular reference to the irrotational congruence admitted by the stationary, axisymmetric spacetime. General precession formulae are obtained for circular orb

Roberto Zucchini

It is shown how the theory of classical $W$--algebras can be formulated on a higher genus Riemann surface in the spirit of Krichever and Novikov. An intriguing relation between the theory of $A_1$ embeddings into simple Lie algebras and the holomorphic geometry of Riemann surfaces is exihibited.

Hugues Chate'

I review recent work on the ``phase diagram'' of the one-dimensional complex Ginzburg-Landau equation for system sizes at which chaos is extensive. Particular attention is paid to a detailed description of the spatiotemporally disordered regimes encountered. The nature of the transition lines separating these phases is discussed, and preliminary resu

William A. Bogley

A combinatorial group-theoretic hypothesis is presented that serves as a necessary and sufficient condition for a union of connected Cockcroft two-complexes to be Cockcroft. This hypothesis has a component that can be expressed in terms of the second homology of groups. The hypothesis is applied to the study of the third homology of groups given by generator

John Meier, Leonard Vanwyk

Given a finite simplicial graph ${\cal G}$, the graph group $G{\cal G}$" is the group with generators in one-to-one correspondence with the vertices of ${\cal G}$ and with relations stating two generators commute if their associated vertices are adjacent in ${\cal G}$. The Bieri-Neumann-Strebel invariant can be explicitly described in terms of the origin

Aurelian Isar

Time evolution of the expectation values of various dynamical operators of the harmonic oscillator with dissipation is analitically obtained within the framework of the Lindblad's theory for open quantum systems. We deduce the density matrix of the damped harmonic oscillator from the solution of the Fokker-Planck equation for the coherent state represent

J. J. van der Bij

The spontaneous symmetry breaking theory of gravity is examined, assuming that the vacuum expectation value of the standard model Higgs is also responsible for the generation of the Planck mass. In this model the physical Higgs couples only with gravitational strength to matter. At presently accessible energies the theory is indistinguishable from the standa

J. A. Gracey

By considering the scaling behaviour of various Feynman graphs at leading order in large $\Nf$ at the non-trivial fixed point of the $d$-dimensional $β$-function of QCD we deduce the critical exponents corresponding to the quark, gluon and ghost anomalous dimensions as well as the anomalous dimensions of the quark-quark-gluon and ghost-ghost-gluon vertices i

E. Ivanov, F. Toppan

We show how to formulate $2$-dimensional supersymmetric $N=1,2$ theories, both massive and conformal, within a manifestly supersymmetric hamiltonian framework, via the introduction of a (super)-Poisson brackets structure defined on superfields. In this approach, as distinct from the previously known superfield hamiltonian formulations, the dynamics is not se

Atsuo Kuniba, Tomoki Nakanishi, Junji Suzuki

Reported are two applications of the functional relations ($T$-system) among a commuting family of row-to-row transfer matrices proposed in the previous paper Part I. For a general simple Lie algebra $X_r$, we determine the correlation lengths of the associated massive vertex models in the anti-ferroelectric regime and central charges of the RSOS models in t

Izawa K. -I

We consider a two-dimensional model of gravity with the cosmological constant as a dynamical variable. The effective cosmological constant is derived when the universe has no initial boundary. It turns out to be extremely small if the universe is sufficiently large.

Yue-Liang Wu

The two principles of spontaneous CP violation and natural flavor conservation can be realized in the $SU(2)_{L}\times U(1)_{Y}$ model with two Higgs doublets. In particular, this model provides a consistent application to the CP violating parameters $ε$ and $ε'/ε$ in kaon decay and the neutron electric dipole moment. The masses of the exotic scalars are

R. N. Mohapatra, S. Nussinov, X. Zhang

We revisit the constraints implied by SN 1987 A observations on the decay rate of a multi-MeV $ν_τ$ decaying into the visible channel $ν_τ\rightarrow e^+ e^- ν_e$, if its lifetime is more than 10 {\it sec.}. We discuss its implication for the minimal left-right symmetric model with see-saw mechanism for neutrino masses. We also speculate on the possible form

Roger Decker, Markus Finkemeier, Erwin Mirkes

We study the effects of non-vanishing pseudoscalar masses in $τ$ decays into three mesons. The hadronic matrix elements are obtained by using the generalized structure of the chiral currents with nonvanishing pseudoscalar masses and implementing the low-lying resonances in the different channels. We demonstrate that suitable angular distributions are sensiti

L. Lavoura, João P. Silva

In the extension of the Dimopoulos--Hall--Raby model of the fermion mass matrices to the neutrino sector, there is an entry in the up-quark and neutrino Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a {\bf 120}, instead of a {\bf 10} or a {\bf 126}, of SO(10). Although this assumption leads to an extra undetermined complex par

K. Funakubo, A. Kakuto, K. Takenaga

The effective potential of electroweak theory with two massless Higgs doublets at finite temperature is studied. We investigate phase structure and critical temperature in this model by numerical analysis without high-temperature expansion. The phase transition is found to be of first order. The critical temperature is shown to be relatively low for typical

K. Suzuki, T. Shigetani, H. Toki

The nucleon structure functions are studied with a special emphasis on diquark correlations inside the nucleon. Assuming a phenomenological diquark-quark model of the nucleon at the low energy hadronic scale, we calculate the leading twist contributions to the nucleon structure functions. We take the Nambu and Jona-Lasinio model for the calculation of the qu

L. Karkkainen, P. Lacock, D. E. Miller, B. Petersson

We investigate the relationship between the high temperature deconfined phase of the SU(2) gauge theory to the phases of the corresponding three dimensional adjoint Higgs model. For various temperatures we simulate the effective theory in a neighbourhood of the physical states, that is of those values of the coupling constants that describe the infrared beha

J. Parry D. S. Salopek, J. M. Stewart

We demonstrate a systematic method for solving the Hamilton-Jacobi equation for general relativity with the inclusion of matter fields. The generating functional is expanded in a series of spatial gradients. Each term is manifestly invariant under reparameterizations of the spatial coordinates (``gauge-invariant''). At each order we solve the Hamilto

Yong Baek Kim, Xiao-Gang Wen

(Short Description) We use a large N renormalization group method to study a model of interacting boson system with a quenched random potential.

Elisabeth Vangioni-Flam, Keith A. Olive, Nikos Prantzos

The determined abundances of primordial $^4He$ and $^7Li$ provide a basis with which to test the standard model of big bang nucleosynthesis in conjunction with the other two light element isotopes $D$ and $^3He$, also produced in the big bang. Overall, consistency in the standard big bang nucleosynthesis model is best achieved for a baryon-to-photon ratio of

G. Giuricin, L. Tamburini, F. Mardirossian, M. Mezzetti

We examine the 10\m\ emission of the central regions of 281 spiral galaxies, after having compiled all ground-based, small-aperture ($\sim$5") broad-band photometric observations at ł$\sim$10\m\ (N magnitudes) published in the literature. We evaluate the compactness of the $\sim$10\m\ emission of galaxy nuclei by comparing these small-beam measures with

Michael S. Turner

Most of the mass density in the Universe---and in the halo of our own galaxy---exists in the form of dark matter. Overall, the contribution of luminous matter (in stars) to the mass density of the Universe is less than 1\%; primordial nucleosynthesis indicates that baryons contribute between 1\% and 10\% of the critical density ($0.01h^{-2}\la Ω_B\la 0.02h^{

B. Schroer

The application of the Tomita-Takesaki modular theory to the Haag-Kastler net approach in QFT yields external (space-time) symmetries as well as internal ones (internal ``gauge para-groups") and their dual counterparts (the ``super selection para-group"). An attempt is made to develop a (speculative) picture on ``quantum symmetry" which links spa

H. Cateau, Y. Matsuo, M. Umeki

A generalized theory of two-dimensional isotropic turbulence is developed based on conformal symmetry. A number of minimal models of conformal turbulence are solved under an extended constraint including both the enstrophy cascade by Kraichnan and the discontinuity of vorticity by Saffman. There are an infinite number of solutions which fall into two differe

Sadhan K. Adhikari, Lauro Tomio, J. P. B. C. DE Melo, T. Frederico

A low-energy shape-independent expansion is suggested for the function $[tan(2ε_{BB})/(2k^2)]$, where $ε_{BB}$ is the Blatt-Biedenharn mixing parameter for the $^3S_1 -$ $^3D_1$ channel. This expansion allows an evaluation of the mixing parameter $ε_{BB}$ from a knowledge of the deuteron asymptotic $D$ to $S$ ratio, pion mass and other low-energy observables

M. M. Sharma, G. A. Lalazissis, P. Ring

The anomalous behaviour of the charge radii of the isotopic chain of Pb nuclei has been studied in the relativistic mean field theory. It has been shown that the relativistic mean field provides an excellent description of the anomalous kink in the isotopic shifts about $^{208}$Pb. This contrasts strongly from the Skyrme mean field, where almost all the know

Nigel J. Kalton, Dirk Werner

We study $M$-ideals of compact operators by means of the property~$(M)$ introduced in \cite{Kal-M}. Our main result states for a separable Banach space $X$ that the space of compact operators on $X$ is an $M$-ideal in the space of bounded operators if (and only if) $X$ does not contain a copy of $\ell_{1}$, has the metric compact approximation property, and

Beata Randrianantoanina

We prove that there is no 1-complemented subspace of finite codimension in separable rearrangament-invariant function spaces.

P. Fendley, H. Saleur

These lecture notes provide an elementary introduction to the study of massless integrable quantum field theory in 1+1 dimensions using ``massless scattering''. Some previously unpublished results are also presented, including a non-perturbative study of Virasoro conserved quantities.

R. N. Mohapatra

Prospects for SO(10) as a minimal grand unification group have recently been heightened by several considerations such as the MSW resolution of the solar neutrino puzzle, baryogenesis, possibility for understanding fermion masses etc. I review the present status of the minimal SO(10) models with special emphasis on the predictions for proton lifetime and pre

Leandros Perivolaropoulos

We investigate analytically and numerically the asymptotic behavior of the Nielsen-Olesen vortex solutions and show that they approach their asymptotic values exponentially but with exponents that differ from the ones quoted in the literature. In particular, it is shown that for values of the Higgs self-coupling that are larger than a critical value, both th

B. Konig, J. G. Korner, M. Kramer

We consider possibilities to determine the handedness of $b \ra c$ current transitions using semileptonic baryonic $Λ_{b} \rightarrow Λ_{c}$ transitions. We propose to analyze the longitudinal polarization of the daughter baryon $Λ_c$ by using momentum-spin correlation measurements in the form of forward-backward (FB) asymmetry measures involving its nonlept

M. Bucher, A. S. Goldhaber

Certain cosmic strings that occur in GUT models such as $SO(10)$ can carry a magnetic flux which acts nontrivially on objects carrying $SU(3)_{color}$ quantum numbers. We show that such strings are non-Abelian Alice strings carrying nonlocalizable colored ``Cheshire" charge. We examine claims made in the literature that $SO(10)$ strings can have a long-r

A. J. Askew, J. Kwiecinski, A. D. Martin, P. J. Sutton

The general properties of the Lipatov or BFKL equation are reviewed. Modifications to the infrared region are proposed. Numerical predictions for the deep-inelastic electron-proton structure functions at small $x$ are presented and confronted with recent HERA measurements.

E. A. Dudas

The effects of possible explicit violation of the Peccei-Quinn symmetry responsible for the solution of the strong CP problem are studied in supersymmetric models. It is shown that automatic models with an abelian $U(1)$ gauge symmetry are easy to construct both in the context of fundamental and composite models of axions. It is argued that it is preferable

S. Y. Choi, J. S. Shim, H. S. Song

The study of factorization in the linearized gravity is extended to the graviton scattering processes with a massive scalar particle, with a massless vector boson and also with a graviton. Every transition amplitude is shown to be completely factorized and the physical implications of their common factors are discussed.

R. Ugoccioni, A. Giovannini, S. Lupia

After a brief review of the theoretical basis of void scaling function properties of hierarchical structure, we analyze the phenomenological consequences at single jet level in Monte Carlo e+e- annihilation events. We find an interesting alternative approach for characterizing quark and gluon jets.

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

We show that eikonal corrections imposed on diffraction dissociation processes calculated in the triple Regge limit, produce a radical change in the energy dependence of the predicted cross section. The induced correction is shown to be in general agreement with the new experimental data measured at the Tevatron.

M. Hasenbusch, K. Pinn

We compare Monte Carlo results for the interface tension and interface energy of the 3-dimensional Ising model with Padé and inhomogeneous differential approximants of the low temperature series that was recently extended by Arisue to $17^{\rm th}$ order in $u=\exp(-4β)$. The series is expected to suffer from the roughening singularity at $u\approx 0.196$. T

J. Mourad

A relation expressing the covariant transformation properties of a relativistic position operator is derived. This relation differs from the one existing in the literature expressing manifest covariance by some factor ordering. The relation is derived in order for the localization of a particle to represent a space-time event. It is shown that there exists a

Lotfi Belkhir, Mohit Randeria

The evolution of the ground state and the excitation spectrum of the two and three dimensional attractive Hubbard model is studied as the system evolves from a Cooper pair regime for weak attraction to a composite boson regime for a strong attraction.

L. Belkhir, X. G. Wu, J. K. Jain

We provide numerical evidence that the ground state of a short range interaction model at $ν=1/2$ is incompressible and spin-singlet for a wide range of repulsive interactions. Furthermore it is accurately described by a trial wave function studied earlier. For the Coulomb interaction we find that this wave function provides a good description of the lowest

Petr Kurka

Dynamical systems at the edge of chaos, which have been considered as models of self-organization phenomena, are marked by their ability to perform nontrivial computations. To distinguish them from systems with limited computing power, we formulate two simplicity criteria for general dynamical systems, and apply them to unimodal systems on real interval. We

S. Matarrese, P. Catelan, F. Lucchin, L. Moscardini

Some recently proposed approximations to follow the non--linear evolution of collisionless matter perturbations in the universe are reviewed. The first one, called frozen--flow approximation, is an Eulerian method within Newtonian theory, and is based on neglecting the role of particle inertia compared to the damping implied by the Hubble drag. The second ap

R. A. C. Croft, G. Efstathiou

We use ensembles of high-resolution CDM simulations to investigate the shape and amplitude of the two point correlation function of rich clusters. The standard scale-invariant CDM model with $Ω=1$ provides a poor description of the clustering measured from the APM rich cluster redshift survey, which is better fitted by models with more power at large scales.

R. A. C. Croft, G. Efstathiou

We use high resolution dissipationless N-body simulations to examine the spatial distribution of galaxy clusters on large scales. The Standard CDM model and two of its main competitors, Low density CDM and Mixed Dark Matter are compared.The two-point correlation function of simulated clusters is compared with an extended survey of APM clusters , and it is fo

David Eisenbud, Alyson Reeves, Burt Totaro

We show that high Veronese subrings of any commutative graded ring have a Grobner basis with all relations of degree 2. (The d-th Veronese subring of a ring A_0 + A_1 + A_2 + ... is the ring A_0 + A_d + A_{2d} + ...; ``high'' means we take d sufficiently large, say at least half the regularity of the ideal defining the original ring.) This gives anot

K. Nagel

A set of very simple rules for driving behavior used to simulate roadway traffic gives realistic results. Because of its simplicity, it is easy to implement the model on supercomputers (vectorizing and parallel), where we have achieved real time limits of more than 4~million~kilometers (or more than 53~million vehicle sec/sec). The model can be used for appl

K. Nagel

We study a model for freeway traffic which includes strong noise taking into account the fluctuations of individual driving behavior. The model shows emergent traffic jams with a self-similar appearance near the throughput maximum of the traffic. The lifetime distribution of these jams shows a short scaling regime, which gets considerably longer if one reduc

Hiroshi Shiba, Tsuneo Suzuki

Monopole and photon contributions to Wilson loops are calculated using Monte-Carlo simulations of SU(2) QCD in the maximally abelian gauge. The string tensions of SU(2) QCD are well reproduced by extended monopole contributions alone.

Alessandro Andretta, John R. Steel

We introduce two new iteration games: the game G, which is a strengthening of the weak iteration game, and the game G+, which is somewhat stronger than G but weaker than the full iteration game of length omega_1. For a countable M elementarily embeddable in some V_{eta}, we can show that II wins G(M,omega_1) and that I does not win the G+(M).

Franco Ferrari

In this paper, the massless Schwinger model or two dimensional quantum electrodynamics is exactly solved on a Riemann surface. The partition function and the generating functional of the correlation functions involving the fermionic currents are explicitly derived using a method of quantization valid for any abelian gauge field theory and explained in the re

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

We investigate the sensitivity of some weak processes to a Cabibbo--Kobayashi--Maskawa mixing in the leptonic sector. Values for mixing angles and masses compatible with several experimental accelerator data were found. We discuss in this context neutrino oscillations, cosmological and astrophysical consequences as well.

C. S. Kim

I summarize our work of electroweak discussion section held at the 14th International Workshop on Weak Interactions and Neutrinos. We discussed about a few physics topics related to electroweak interactions, including $B$ and $K$ physics and weak flavor physics.

H. Kröger, S. Lantagne, K. J. M. Moriarty

We have studied the scalar $ϕ^4$-model in the symmetric phase and the non--compact $U(1)$ gauge theory on a momentum lattice using the Langevin equation for generating configurations. In the $ϕ^4$-model we have analyzed the renormalized mass and in the $U(1)$-model we have analyzed the Wilson loop operator. We used a second order algorithm for solving the La

Hiroshi Shiba, Tsuneo Suzuki

An effective monopole action is derived from vacuum configurations after abelian projection in the maximally abelian gauge in $SU(2)$ QCD. Entropy dominance over energy of monopole loops is seen on the renormalized lattice with the spacing $b>b_c\simeq 5.2\times10^{-3} Λ_L^{-1}$ when the physical volume of the system is large enough. QCD confinement may be i

J. Mund, R. Schrader

Using the theory of fibre bundles, we provide several equivalent intrinsic descriptions for the Hilbert spaces of $n$ ``free'' nonrelativistic and relativistic plektons in two space dimensions. These spaces carry a ray representation of the Galilei group and a unitary representation of the Poincaré group respectively. In the relativistic case we also

V. I. Man'ko, G. Marmo, P. Vitale, F. Zaccaria

For all three--dimensional Lie algebras the construction of generators in terms of functions on 4-dimensional real phase space is given with a realization of the Lie product in terms of Poisson brackets. This is the classical Jordan--Schwinger map which is also given for the deformed algebras ${\cal {SL}}_{q}(2,\R)$, ${\cal E}_{q} (2)$ and ${\cal H}_q(1)$. T

John Cardy

The mean area of two-dimensional unpressurised vesicles, or self-avoiding loops of fixed length $N$, behaves for large $N$ as $A_0 N^{3/2}$, while their mean square radius of gyration behaves as $R^2_0 N^{3/2}$. The amplitude ratio $A_0/R_0^2$ is computed exactly and found to equal $4π/5$. The physics of the pressurised case, both in the inflated and collaps

M. Cassandro, P. K. Mitter

We study the scaling limit of a model of a tethered crumpled D-dimensional random surface interacting through an exclusion condition with a fixed impurity in d-dimensional Euclidean space by the methods of Wilson's renormalization group. In this paper we consider a hierarchical version of the model and we prove rigorously the existence of the scaling lim

Subhashis Nag

There is a completely natural and intimate relationship between the diffeomorphism group of the circle and the Teichmüller spaces of Riemann surfaces discovered by us in 1988. Such a relationship had been sought-after by physicists from conjectures connecting the loop-space approach to string theory with the path-integral approach. Precisely, the remarkable

Alex Pomarol, Carl Schmidt

We analyze the energy distribution of the leptons coming from the top decay $t\ra b\hc,\ bW^+\ra bl^+ν$. The correlation between the lepton energy distribution and the top spin may be useful for distinguishing the $\hc$ signature from the $W$ background. Such a correlation can also be useful for disentangling the two different $\hc \bar tb$ couplings and det

Edward Shuryak

We review the current status of the problem of chiral symmetry restoration, discussing an open question of whether at the $SU(N_f)_A$ restoration point $T=T_c$ the $U(1)_A$ chiral symmetry is or is not (approximately) restored. New lattice and instanton-based studies are considered, and some new calculations are suggested to clarify the issue. We also specul

V. S. Fadin, R. Fiore, A. Quartarolo

One loop corrections to the coupling of the reggeized gluon to quarks are calculated in QCD. Combining this result with the known corrections to the gluon-gluon-reggeon vertex, we check the self-consistency of the representation of the amplitudes with gluon quantum numbers and negative signature in the $t$-channel in terms of Regge pole contribution.

P. Colangelo

I review the QCD sum rules calculations of the form factors governing the semileptonic decays of charmed and beauty mesons. In particular, I discuss the predicted dependence of the various form factors on $q^2$ and how it can be obtained for the form factors of vector and axial currents. In some cases the $q^2$ dependence, computed by QCD sum rules, is diffe

C. Gobbi, F. Iachello, D. Kusnezov

We present a detailed study of the two-body strong decays of light mesons. Both the space part and the spin-flavor-color part of the wave functions are generated algebraically and closed forms are obtained for all decays. Experimental deviations from our systematics are seen to be suggestive of both missing mesons and exotic QCD configurations.

Tanguy Altherr

Upon using the same theoretical framework, I describe two interesting decay processes: the electromagnetic plasmon decay into neutrinos, which can be the dominant cooling mechanism for red giants and white dwarfs, and the gluonic plasmon decay into quarks, which can be measured in ultra-relativistic heavy-ion collisions.

Jiang Liu, Gino Segrè

We discuss unstable particle mixing in CP-violating weak decays. It is shown that for a completely degenerate system unstable particle mixing does not introduce a CP-violating partial rate difference, and that when the mixings are small only the off-diagonal mixings are relevant. Also, in the absence of mixing, unstable particle wave function renormalization

Nils A. Törnqvist

A systematic study of possible deuteronlike two-meson bound states, {\it deusons}, is presented. Previous arguments that many such bound states may exist are elaborated with detailed arguments and numerical calculations including, in particular, the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron

JR Forshaw, RG Roberts

Two-jet production from the direct photon contribution at HERA is a sensitive measure of the small-$x$ gluon in the proton. We propose measurements of ratios of the jet cross-sections which will clearly distinguish between gluons with or without singular behaviour at small $x$. Furthermore, we show that analogous ratio measurements for the resolved photon co

D. Nunez, H. Quevedo

Einstein's equations for stationary axisymmetric fields are reformulated as the equations for affine geodesics in a two--dimensional space. The affine collineations of this space are investigated and used to relate explicit solutions of Einstein's equations with different physical properties. Particularly, the solutions describing the exterior fields

J. W. Barrett, T. J. Foxon

We consider the simplicial state-sum model of Ponzano and Regge as a path integral for quantum gravity in three dimensions. We examine the Lorentzian geometry of a single 3-simplex and of a simplicial manifold, and interpret an asymptotic formula for $6j$-symbols in terms of this geometry. This extends Ponzano and Regge's similar interpretation for Eucli

K. Maeda, T. Tachizawa, T. Torii, T. Maki

Two types of self-gravitating particle solutions found in several theories with non-Abelian fields are smoothly connected by a family of non-trivial black holes. There exists a maximum point of the black hole entropy, where the stability of solutions changes. This criterion is universal, and the changes in stability follow from a catastrophe-theoretic analys

G. George Batrouni, Alex Hansen, Gerald H. Ristow

We show that depending on the disorder, a small noise added to the threshold distribution of the fuse network may or may not completely change the subsequent breakdown process. When the threshold distribution has a lower cutoff at a finite value and a power law dependence towards large thresholds with an exponent which is less than $0.16\pm0.03$, the network

C. de C. Chamon, X. G. Wen

We study the transition between sharp and smooth density distributions at the edges of Quantum Hall Liquids in the presence of interactions. We find that, for strong confining potentials, the edge of a $ν=1$ liquid is described by the $Z_F=1$ Fermi Liquid theory, even in the presence of interactions, a consequence of the chiral nature of the system. When the

R. Bulla, J. Keller, T. Pruschke

Recently, a functional integral representation was proposed by Weller (Weller, W.: phys.~stat.~sol.~(b) {\bf 162}, 251 (1990)), in which the fermionic fields strictly satisfy the constraint of no double occupancy at each lattice site. This is achieved by introducing spin dependent Bose fields. The functional integral method is applied to the single impurity

Washington Taylor

This thesis describes a new approach to conformal field theory. This approach combines the method of coadjoint orbits with resolutions and chiral vertex operators to give a construction of the correlation functions of conformal field theories in terms of geometrically defined objects. Explicit formulae are given for representations of Virasoro and affine alg

Subhashis Nag, Dennis Sullivan

The Universal Teichmüller Space, $T(1)$, is a universal parameter space for all Riemann surfaces. In earlier work of the first author it was shown that one can canonically associate infinite- dimensional period matrices to the coadjoint orbit manifold $Diff(S^1)/Mobius(S^1)$ -- which resides within $T(1)$ as the (Kirillov-Kostant) submanifold of ``smooth poi

Stephen J. Montgomery-Smith

Let S_k be the k-th partial sum of Banach space valued independent identically distributed random variables. In this paper, we compare the tail distribution of ||S_k|| with that of ||S_j||, and deduce some tail distribution maximal inequalities. Theorem: There is universal constant c such that for j < k Pr(||S_j|| > t) <= c Pr(||S_k|| > t/c).

R. D. Ball, R. S. Thorne

We present a comprehensive discussion of the consistency of the effective quantum field theory of a single $Z_2$ symmetric scalar field. The theory is constructed from a bare Euclidean action which at a scale much greater than the particle&#39;s mass is constrained only by the most basic requirements; stability, finiteness, analyticity, naturalness, and glob

P. B Wiegmann, A. V. Zabrodin

We present a new approach to the problem of Bloch electrons in magnetic field,\\ by making explicit a natural relation between magnetic translations and the\\quantum group $U_{q}(sl_2)$. The approach allows to express the spectrum and\\\ the Bloch function as solutions of the Bethe-Ansatz equations typical for com\\pletely integrable quantum systems

Charles Nash, Denjoe O&#39; Connor

We give a quantum field theoretic derivation of the formula obeyed by the Ray-Singer torsion on product manifolds. Such a derivation has proved elusive up to now. We use a BRST formalism which introduces the idea of an infinite dimensional Universal Gauge Fermion, and is of independent interest being applicable to situations other than the ones considered he

H. B. Gao, H. Römer

In this paper a two dimensional non-linear sigma model with a general symplectic manifold with isometry as target space is used to study symplectic blowing up of a point singularity on the zero level set of the moment map associated with a quasi-free Hamiltonian action. We discuss in general the relation between symplectic reduction and gauging of the symple

Gregory Moore

The bracket operation on mutually local BRST classes may be combined with Lorentz invariance and analyticity to write an infinite set of finite difference relations on string scattering amplitudes. When combined with some simple physical criteria these relations uniquely determine the genus zero string $S$-matrix for $N\leq 26$-particle scattering in $\IR^{2