July 1992 arXiv papers — page 3

Hao-wen Xi, Jorge Vinals, J. D. Gunton

We present a numerical study of a model of pattern formation following a convective instability in a non-Boussinesq fluid. It is shown that many of the features observed in convection experiments conducted on $CO_{2}$ gas can be reproduced by using a generalized two-dimensional Swift-Hohenberg equation. The formation of hexagonal patterns, rolls and spirals

T. A. Larsson

Conformal fields are a recently discovered class of representations of the algebra of vector fields in $N$ dimensions. Invariant first-order differential operators (exterior derivatives) for conformal fields are constructed.

T. A. Larsson

$Vect(N)$, the algebra of vector fields in $N$ dimensions, is studied. Some aspects of local differential geometry are formulated as $Vect(N)$ representation theory. There is a new class of modules, {\it conformal fields}, whose restrictions to the subalgebra $sl(N+1) \subset Vect(N)$ are finite-dimensional $sl(N+1)$ representations. In this regard they are

J. Greensite

It is shown that the probability distribution $P(λ)$ for the effective cosmological constant is sharply peaked at $λ=0$ in stochastic (or "fifth-time") stabilized quantum gravity. The effect is similar to the Baum-Hawking mechanism, except that it comes about due to quantum fluctuations, rather than as a zeroth-order (in $\hbar$) semiclassical effect

François Delduc, Jean-Loup Gervais, Mikhail Saveliev

On the example of nonabelian Toda type theory associated with the Lie superalgebra $osp(2|4)$ we show that this integrable dynamical system is relevant to a black hole background metric in the corresponding target space. In the even sector the model under consideration reduces to the exactly solvable conformal theory (nonabelian $B_2$ Toda system) in the pre

M. Karowski, R. Schrader, FU-Berlin

For the special case of the quantum group $SL_q (2,{\bf C})\ (q= \exp πi/r,\ r\ge 3)$ we present an alternative approach to quantum gauge theories in two dimensions. We exhibit the similarities to Witten's combinatorial approach which is based on ideas of Migdal. The main ingredient is the Turaev-Viro combinatorial construction of topological invariants

H. W. Braden, H. S. Cho, J. D. Kim, I. G. Koh

The leading and the subleading Landau singularities in affine Toda field theories are examined in some detail. Formulae describing the subleading simple pole structure of box diagrams are given explicitly. This leads to a new and nontrivial test of the conjectured exact S-matrices for these theories. We show that to the one-loop level the conjectured S-matri

Neil Marcus

We show that the N=2 open string describes a theory of self-dual Yang Mills (SDYM) in (2,2) dimensions. The coupling to the closed sector is described by SDYM in a Kahler background, with the Yang-Mills fields providing a source term to the self-duality equation in the gravity sector. The four-point S-matrix elements of the theory vanish, so the tree-level u

Alexander Kusenko

We introduce two new sets of invariant functions of quark mass matrices, which express the constraints on these mass matrices due to knowledge of the quark mixing matrix. These invariants provide a very simple method to test candidate forms for mass matrices.

J. L. Hewett, T. G. Rizzo

We examine how the abilities of an SDC-like detector to discover and identify the origin of a new neutral gauge boson are affected by $Z_1-Z_2 $ mixing and by variations in detector parameters such as lepton pair mass resolution, particle identification efficiency, and rapidity coverage. Also examined is the sensitivity of these results to variations in stru

A. C. Mattingly, P. M. Stevenson

We apply the optimization procedure based on the Principle of Minimal Sensitivity to the third-order calculation of $\R$. The effective couplant remains finite, freezing to a value $α_s/π= 0.26$ at low energies. Using Poggio-Quinn-Weinberg smearing we find good agreement between theory and experiment right down to zero energy.

M. Pietroni

We study the electroweak phase transition in a supersymmetric version of the Standard Model, in which a gauge singlet superfield is added to the Higgs sector. We show that the order of the transition is determined by the trilinear soft supersymmetry breaking terms rather than by the $O ( m^{3} T )$ term in the 1-loop, $T\neq0$ corrections. This fact removes

Thomas Appelquist, George Triantaphyllou

It is shown that a technicolor theory containing a color-octet technipion, usually denoted by $P^{0'}_{8}$, will give rise to an enhancement of $t \bar t$ production at the Tevatron, LHC and SSC, via the process $gg \rightarrow P^{0'}_{8} \rightarrow t \bar t$. The relevant cross-sections are computed taking into account the large lower bound on the

Yosef Nir, Uri Sarid

The values of $\sin (2 α)$ and $\sin (2 β)$, where $α$ and $β$ are angles of the unitarity triangle, will be readily measured in a B factory (and maybe also in hadron colliders). We study the standard model constraints in the $\sin (2 α) - \sin (2 β)$ plane. We use the results from recent analyses of $f_B$ and $τ_b|V_{cb}|^2$ which take into account heavy qu

Miriam Leurer

Recently, it was suggested that the 17 keV neutrino does not mix with the electron neutrino in the weak interactions. Instead, the $β$ decay mode involving the 17 keV neutrino is induced by a completely new interaction, presumably mediated by leptoquarks. A previous model for the ``unmixed 17 keV neutrino" suffers from difficulties with experimental data

Pawel Pliszka, Enzo Marinari

We investigate the time evolution of the heteropolymer model introduced by Iori, Marinari and Parisi to describe some of the features of protein folding mechanisms. We study how the (folded) shape of the chain evolves in time. We find that for short times the mean square distance (squared) between chain configurations evolves according to a power law, $D \si

Martin Lüscher, Peter Weisz, Rainer Sommer, Ulli Wolff

A finite-size scaling technique is applied to the SU(2) gauge theory (without matter fields) to compute a non-perturbatively defined running coupling alpha(q) for a range of momenta q given in units of the string tension K. We find that already at rather low q, the evolution of alpha(q) is well described by the 2-loop approximation to the Callan-Symanzik bet

Martin Lüscher, Rajamani Narayanan, Peter Weisz, Ulli Wolff

Following Symanzik we argue that the Schrödinger functional in lattice gauge theories without matter fields has a well-defined continuum limit. Due to gauge invariance no extra counter terms are required. The Schrödinger functional is, moreover, accessible to numerical simulations. It may hence be used to study the scaling properties of the theory and in par

Ofer Biham, Mark Kvale

A systematic numerical technique for the calculation of unstable periodic orbits in the stadium billiard is presented. All the periodic orbits up to order $p=11$ are calculated and then used to calculate the average Lyapunov exponent and the topological entropy. Applications to semiclassical quantization and to experiments in mesoscopic systems and microwave

Murat Gunaydin

We study the chiral rings in N=2 and N=4 superconformal algebras. The chiral primary states of N=2 superconformal algebras realized over hermitian triple systems are given. Their coset spaces G/H are hermitian symmetric which can be compact or non-compact. In the non-compact case, under the requirement of unitarity of the representations of G we find an infi

G. von Gehlen

We calculate the low-lying part of the spectrum of the $Z_3$-symmetrical chiral Potts quantum chain in its self-dual and integrable versions, using numerical diagonalisation of the hamiltonian for $N \leq 12$ sites and extrapolation $N \ra \infty$. From the sequences of levels crossing we show that the massive phases have oscillatory correlation functions. W

Igor Pesando

Within the Quantum Action Principle framework we show the perturbative renormalizability of previously proposed topological lagrangian à la Witten-Fujikawa describing polymers, then we perform a 2 loop computation. The theory turns out to have the same predictive power of De Gennes theory, even though its running coupling constants exhibit a very peculiar be

J. Ambjorn, C. F. Kristjansen, Y. M. Makeenko

We describe an iterative scheme which allows us to calculate any multi-loop correlator for the complex matrix model to any genus using only the first in the chain of loop equations. The method works for a completely general potential and the results contain no explicit reference to the couplings. The genus $g$ contribution to the $m$--loop correlator depends

Michael Flohr

Two series of W-algebras with two generators are constructed from chiral vertex operators of a free field representation. If $c = 1 - 24k$, there exists a W(2,3k) algebra for k in $Z_{+}/2$ and a W(2,8k) algebra for k in $Z_{+}/4$. All possible lowest-weight representations, their characters and fusion rules are calculated proving that these theories are rat

J M Flynn, N Isgur

This report is a combined version of two talks presented by the authors at the Edinburgh $b$-physics Workshop, December 1991. It presents the ideas of heavy quark symmetry and gives an introduction to some applications. The references indicate where to go for more information: they are not intended to be complete, nor do they necessarily refer to the origina

Ming Lu, Mark B. Wise, Martin J. Savage

Short distance physics involving virtual top and charm quarks contributes to $μ^+$ (and $μ^-$) polarization in the decay $K^+ \rightarrow π^+ μ^+ μ^-$. Measurement of the parity violating asymmetry $(Γ_R - Γ_L)/(Γ_R + Γ_L)$, where $Γ_R$ and $Γ_L$ are the rates to produce right and left-handed $μ^+$, may provide valuable information on the unitarity triangle.

Herbert Dreiner, Graham G. Ross

If the present baryon-asymmetry is due to a Planck or GUT-scale matter asymmetry then baryon- or lepton-number violating processes are constrained by the condition that they do not subsequently erase this asymmetry. We present a revision of the analysis of sphaleron baryon-number violating processes in the standard model including lepton-mass effects. We fin

J. Ambjorn, A, Irback, J. Jurkiewicz

We analyze numerically the critical properties of a two-dimensional discretized random surface with extrinsic curvature embedded in a three-dimensional space. The use of the toroidal topology enables us to enforce the non-zero external extension without the necessity of defining a boundary and allows us to measure directly the string tension. We show that a

U. Hansmann, B. A. Berg, T. Neuhaus

To investigate order-order interfaces, we perform multimagnetical Monte Carlo simulations of the $2D$ and $3D$ Ising model. Stringent tests of the numerical methods are performed by reproducing with high precision exact $2D$ results. In the physically more interesting $3D$ case we estimate the amplitude $F^s_0$ of the critical interfacial tension.

M. Cristina Marchetti

The pair interaction between magnetic flux lines in a semi-infinite slab of an anisotropic type-II superconductor in an external field is derived in the London limit. The case where the applied field is normal to the superconductor/vacuum interface is considered. The presence of stray fields near the surface leads to an additional contribution to the repulsi

Alessandro Gualzetti, Silvia Penati, Daniela Zanon

We consider $N=1$ supersymmetric Toda theories which admit a fermionic untwisted affine extension, i.e. the systems based on the $A(n,n)$, $D(n+1,n)$ and $B(n,n)$ superalgebras. We construct the superspace Miura trasformations which allow to determine the W-supercurrents of the conformal theories and we compute their renormalized expressions. The analysis of

Stephen P. Martin

We catalog some simple conditions which are sufficient to guarantee that R-parity survives as an unbroken gauged discrete subgroup of the continuous gauge symmetry in certain supersymmetric extensions of the standard model.

Y. Frishman, J. Sonnenschein

This review is devoted to the application of bosonization techniques to two dimensional QCD. We start with a description of the ``abelian bosonization". The methods of the abelian bosonization are applied to several examples like the Thirring model, the Schwinger model and QCD$_2$. The failure of this scheme to handle flavored fermions is explained. Witt

Thorsten Ohl

This manual describes version 1.0 of the Monte Carlo event generator KROWIG for deep inelastic lepton hadron scattering at HERA. KROWIG combines the implementation of QED radiative corrections in KRONOS with the QCD parton showers and cluster fragmentation of HERWIG.

J. Lopez, D. Nanopoulos, A. Zichichi

We show that within the framework of the minimal $SU(5)$ supergravity model, radiatively-induced electroweak symmetry breaking and presently available experimental lower bounds on nucleon decay, impose severe constraints on the available parameter space of the model which correspond to fine-tuning of the model parameters of over two orders of magnitude. Furt

B. Blok, M. Shifman

We discuss the Isgur-Wise function $ξ(y)$ in the small velocity (SV) limit within the QCD sum rule method. The behavior of $ξ(y)$ in the SV limit is sensitive to the particular form of the duality relations used to decontaminate the sum rule predictions from the continuum contribution. Peculiarities of the duality relations in the problem at hand are reveale

Ying-Hong Li, S. Teitel

We carry out Monte Carlo simulations of the uniformly frustrated 3d XY model as a model for vortex line fluctuations in a high Tc superconductor. A density of vortex lines of f=1/25 is considered. We find two sharp phase transitions. The low T phase is an ordered vortex line lattice. The high T normal phase is a vortex line liquid with much entangling, cutti

N. J. MacKay

We use the method of the tensor product graph to construct rational (Yangian invariant) solutions of the Yang-Baxter equation in fundamental representations of $c_n$ and thence the full set of $c_n$-invariant factorized $S$-matrices. Brief comments are made on their bootstrap structure and on Belavin's scalar Yangian conserved charges.

Grzegorz Swiatek

It is shown that for non-hyperbolic real quadratic polynomials topological and quasisymmetric conjugacy classes are the same. By quasiconformal rigidity, each class has only one representative in the quadratic family, which proves that hyperbolic maps are dense.

Spiros A. Argyros, Irene Deliyanni

To any pair ( M , theta ) where M is a family of finite subsets of N compact in the pointwise topology, and 0<theta < 1 , we associate a Tsirelson-type Banach space T_M^theta . It is shown that if the Cantor-Bendixson index of M is greater than n and theta >{1/n} then T_M^theta is reflexive. Moreover, if the Cantor-Bendixson index of M is greater than omega

Jnan Maharana, John H. Schwarz

Noncompact groups, similar to those that appeared in various supergravity theories in the 1970&#39;s, have been turning up in recent studies of string theory. First it was discovered that moduli spaces of toroidal compactification are given by noncompact groups modded out by their maximal compact subgroups and discrete duality groups. Then it was found that

A. Hasenfratz, K. Jansen, Y. Shen

In this paper we investigate how the phase diagram of a U(1) symmetric Higgs-Yukawa system depends on the scalar self coupling $λ$. The phase diagram of similar models with continuous symmetry were extensively studied in the infinite scalar self coupling $λ=\infty$ limit. Recent analytical and numerical calculations at zero self coupling showed qualitatively

F. Guinea, M. Ueda

A discrete charge transfer in a small tunnel junction where Coulomb interactions are important can excite electron-hole pairs near the Fermi level. We use a simple model to study the associated nonequilibrium properties and found two novel effects: (i) for junctions with electrodes of the same electronic properties, a leakage current exists within the Coulom

Per Arne Slotte

The phase diagram of a lattice microemulsion model proposed by Ciach, Høye and Stell is studied using mean-field theory and Monte Carlo simulations. Surfactant directional degrees of freedom are summed out exactly before mean-field theory is applied, and the resulting phase diagrams are much improved compared with previous mean-field results. The critical li

Zhu Yang

We show that, the lattice regularization of chiral gauge theories proposed by Kaplan, when applied to a (2+1)-dimensional domain wall, produces a (1+1)-dimensional theory at low energy even if gauge anomaly produced by chiral fermions does not cancel. But the corresponding statement is not true in higher dimensions.

Mirjam Cvetič, Paul Langacker

We point out that the production cross section of $pp\to V&#39;V$, with $V&#39;=W&#39;,Z&#39;$ and $V=W,Z$ is a useful diagnostic of $V&#39;$ gauge couplings at future hadron colliders. For $M_{Z&#39;}\simeq1$ TeV it would allow determination of combinations of $Z&#39;$ gauge couplings to the quarks to around 10 percent. An analysis of the extraction of gaug

R. E. Cutkosky

Baryon mass splittings are analyzed in terms of a simple model with general pairwise interactions. At present, the $Δ$ masses are poorly known from experiments. Improvement of these data would provide an opportunity to make a significant test of our understanding of electromagnetic and quark-mass contributions to hadronic masses. The problem of determining r

I. I. Bigi, N. G. Uraltsev, A. I. Vainshtein

We present a selfconsistent method for treating nonperturbative effects in inclusive nonleptonic and semileptonic decays of heavy flavour hadrons. These effects give rise to powerlike corrections $\propto 1/m_Q^n\,$, $n \ge 2$ with $m_Q$ denoting the heavy quark mass.The leading correction to the semileptonic branching ratio occurs for n=2. It is expressed i

M. F. L. Golterman, D. N. Petcher, E. Rivas

We have studied the Eichten--Preskill proposal for constructing lattice chiral gauge theories using both strong and weak coupling methods. The results indicate that this proposal is unlikely to work due to a dynamical behavior similar to that of the Smit--Swift proposal, which also does not give rise to chiral fermions.

M. F. L. Golterman, D. N. Petcher

Our work on models with Wilson--Yukawa couplings is reviewed. Conclusions include the failure of such models to produce continuum chiral gauge theories.

Kåre Olaussen

A convenient way to calculate $N$-particle quantum partition functions is by confining the particles in a weak harmonic potential instead of using a finite box or periodic boundary conditions. There is, however, a slightly different connection between partition functions and thermodynamic quantities with such volume regularization. This is made explicit, and

W. A. Sabra

The Polyakov&#39;s &#34;soldering procedure&#34; which shows how two-dimensional diffeomorphisms can be obtained from SL(2,R) gauge transformations is discussed using the free-field representation of SL(2,R) current algebra. Using this formalism, the relation of Polyakov&#39;s method to that of the Hamiltonian reduction becomes transparent. This discussion i

J. M. Figueroa-O&#39;Farrill, J. Mas, E. Ramos

A two-boson realization of the second hamiltonian structure for the KP hierarchy has recently appeared in the literature. Furthermore, it has been claimed that this is also a realization of the hierarchy itself. This is surprising because it would mean that the dynamics of the KP hierarchy---which in its usual formulation requires an infinite number of field

Avinash Dhar, Gautam Mandal, Spenta R. Wadia

We apply the method of coadjoint orbits of \winf-algebra to the problem of non-relativistic fermions in one dimension. This leads to a geometric formulation of the quantum theory in terms of the quantum phase space distribution of the fermi fluid. The action has an infinite series expansion in the string coupling, which to leading order reduces to the previo

Katsushi Ito, Jens Ole Madsen, Jens Lyng Petersen

We present explicit free field representations for the $N=4$ doubly extended superconformal algebra, $\tilde{\cal{A}}_γ$. This algebra generalizes and contains all previous $N=4$ superconformal algebras. We have found $\tilde{\cal{A}}_γ$ to be obtained by hamiltonian reduction of the Lie superalgebra $D(2|1;α)$. In addition, screening operators are explicitl

Katsushi Ito, Jens Ole Madsen, Jens Lyng Petersen

We study the classical and quantum $G$ extended superconformal algebras from the hamiltonian reduction of affine Lie superalgebras, with even subalgebras $G\oplus sl(2)$. At the classical level we obtain generic formulas for the Poisson bracket structure of the algebra. At the quantum level we get free field (Feigin-Fuchs) representations of the algebra by u

Alberto Blasi, Nicola Maggiore

The two--dimensional topological BF model is considered in the Landau gauge in the framework of perturbation theory. Due to the singular behaviour of the ghost propagator at long distances, a mass term to the ghost fields is introduced as infrared regulator. Relying on the supersymmetric algebraic structure of the resulting massive theory, we study the infra

Fabian H. L. Essler, Vladimir E. Korepin

We construct the enveloping fundamental spin model of the t-J hamiltonian using the Quantum Inverse Scattering Method (QISM), and present all three possible Algebraic Bethe Ansätze. Two of the solutions have been previously obtained in the framework of Coordinate Space Bethe Ansatz by Sutherland and by Schlottmann and Lai, whereas the third solution is new.

S. A. Bludman, N. Hata, D. C. Kennedy, P. G. Langacker

Constraints on the core temperature (T_c) of the Sun and on neutrino- oscillation parameters are obtained from the existing solar neutrino data, including the recent GALLEX and Kamiokande III results. (1) A purely astrophysical solution to the solar neutrino problem is strongly disfavored by the data: the best fit in a cooler Sun model requires an 8% reducti

V. Barger, Kingman Cheung, R. J. N. Phillips, A. L. Stange

The prospects for discovery of the five Higgs bosons of the minimal supersymmetric standard model are assessed for existing and planned future colliders, including LEP\,I, LEP\,II, LHC and SSC. As a benchmark for comparisons, we take a top-quark mass $m_t= 150\,$GeV and squark mass parameter $\tilde m= 1\,$TeV in evaluating one-loop radiative corrections; so

B. K. Jennings, G. A. Miller

Color transparency occurs if a small-sized wave packet, formed in a high momentum transfer process, escapes the nucleus before expanding. The time required for the expansion depends on the masses of the baryonic components of the wave packet. Measured proton diffractive dissociation and electron deep inelastic scattering cross sections are used to examine an

W. R. Greenberg, G. A. Miller

Color transparency CT depends on the formation of a wavepacket of small spatial extent. It is useful to interpret experimental searches for CT with a multiple scattering scattering series based on wavepacket-nucleon scattering instead of the standard one using nucleon-nucleon scattering. We develop several new techniques which are valid for differing ranges

Z Berezhiani, A Yu Smirnov, J W F Valle

We consider a class of simplest Majoron models where neutrino- majoron couplings can be in the range $g \sim 10^{-5}-10^{-3}$ leading to the observability of neutrinoless double beta decay with majoron emission. The majoron is a singlet of the electroweak gauge symmetry, thus avoiding conflict with the LEP data on Z decay, which rules out the triplet and dou

R. Holman, T. W. Kephart, Soo-Jong REY

We show that charged Eguchi-Hanson instantons provide a concrete and calculable new source of intrinsic Peccei-Quinn symmetry breaking by quantum gravity. The size of this breaking is shown to depend sensitively on the short distance details of a given theory, but is generically suppressed by fermion zero modes. Demanding that these gravitational effects not

M. Grabenstein, K. Pinn

We study the kinematics of multigrid Monte Carlo algorithms by means of acceptance rates for nonlocal Metropolis update proposals. An approximation formula for acceptance rates is derived. We present a comparison of different coarse-to-fine interpolation schemes in free field theory, where the formula is exact. The predictions of the approximation formula fo

Ken Yee

In conjunction with recent numerical \hbox{$λ~\partial_0 A_0 + \nabla\cdot\vec{A} =0$} ``$λ$-gauge&#39;&#39; results reported in a companion paper, we construct an $N\to\infty$ Wilson loop picture of $λ$-gaugefixing in which (I)the $λ$-gauge expectation value of a link chain $C$ is the weighted sum over Wilson loops made by joining to $C$ all selfavoiding ch

Vladimir Privman, Mustansir Barma

We develop a new fast-diffusion approximation for the kinetics of deposition of extended objects on a linear substrate, accompanied by diffusional relaxation. This new approximation plays the role of the mean-field theory for such processes and is valid over a significantly larger range than an earlier variant, which was based on a mapping to chemical reacti

C. P. Burgess, James M. Cline

Wrong preprint number changed on previous version.

B. Gato-Rivera, A. M. Semikhatov

The BRST invariance condition in a highest-weight representation of the topological ($\equiv$ twisted $N=2$) algebra captures the `invariant&#39; content of two-dimensional gravity coupled to matter. The standard DDK formulation is recovered by splitting the topological generators into $c=-26$ reparametrization ghosts+matter +`Liouville&#39;, while a similar

Kenichiro Aoki, Santiago Peris

The dependence of the $ρ$ parameter on the mass of the Higgs scalar and the top quark is computed non--perturbatively using the $1/N_F$ expansion in the standard model. We find an explicit expression for the $ρ$ parameter that requires the presence of a physical cutoff. This should come as no surprise since the theory is presumably trivial. By taking this cu

A. Mikovic

We study canonical quantization of a class of 2d dilaton gravity models, which contains the model proposed by Callan, Giddings, Harvey and Strominger. A set of non-canonical phase space variables is found, forming an $SL(2,{\bf R}) \times U(1)$ current algebra, such that the constraints become quadratic in these new variables. In the case when the spatial ma

J. Isberg, U. Lindström, B. Sundborg

The tensionless limit of the free bosonic string is space-time conformally symmetric classically. Requiring invariance of the quantum theory in the light cone gauge tests the reparametrization symmetry needed to fix this gauge. The full conformal symmetry gives stronger constraints than the Poincaré subalgebra. We find that the symmetry may be preserved in a

Waikwok Kwong, S. P. Rosen

The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is studied in the context of nonet symmetry. We have found that it is badly broken in the PP channels and in the P sector of the PV channels as expected from the non-ideal mixing of the ηand the η&#39;. In the VV channels, it is also found that nonet symmetry does not describe the data w

V. Barger, Kingman Cheung, R. J. N. Phillips, A. L. Stange

The lightest CP-even Higgs boson $h$ in the minimum supersymmetric standard model (MSSM) has a mass upper bound depending on the top quark and squark masses. An $e^+e^-$ collider with enough energy and luminosity to produce $h+Z$ at measurable rates up to the maximum $h$ mass would cover the entire MSSM parameter space, if $h+A$ production was also searched

Jean Cleymans, Helmut Satz

We provide a method to test if hadrons produced in high energy heavy ion collisions were emitted at freeze-out from an equilibrium hadron gas. Our considerations are based on an ideal gas at fixed temperature $T_f$, baryon number density $n_B$, and vanishing total strangeness. The constituents of this gas are all hadron resonances up to a mass of 2 GeV; they

Vladimir Privman

We present an introduction to modern theories of interfacial fluctuations and the associated interfacial parameters: surface tension and surface stiffness, as well as their interpretation within the capillary wave model. Transfer matrix spectrum properties due to fluctuation of an interface in a long-cylinder geometry are reviewed. The roughening transition

Vladimir Privman

We present exact results for a lattice model of cluster growth in 1D. The growth mechanism involves interface hopping and pairwise annihilation supplemented by spontaneous creation of the stable-phase, +1, regions by overturning the unstable-phase, -1, spins with probability p. For cluster coarsening at phase coexistence, p=0, the conventional structure-fact

Vladimir Privman

A system of particles hopping on a line, singly or as merged pairs, and annihilating in groups of three on encounters, is solved exactly for certain symmetrical initial conditions. The functional form of the density is nearly identical to that found in two-body annihilation, and both systems show non-mean-field, ~1/t**(1/2) instead of ~1/t, decrease of parti

HoSeong La

Eq.(19) is added and related issues are further clarified. Also some typos and signs a re corrected.

Thomas Strobl

The covariant form of the field equations for two--dimensional $R^2$--gravity with torsion as well as its Hamiltonian formulation are shown to suggest the choice of the light--cone gauge. Further a one--to--one correspondence between the Hamiltonian gauge symmetries and the diffeomorphisms and local Lorentz transformations is established, thus proving that t

Timothy R. Klassen, Ezer Melzer

By viewing the Sine-Gordon and massive Thirring models as perturbed conformal field theories one sees that they are different (the difference being observable, for instance, in finite-volume energy levels). The UV limit of the former (SGM) is a gaussian model, that of the latter (MTM) a so-called {\it fermionic} gaussian model, the compactification radius of

Donald E. Knuth

The polynomials that arise as coefficients when a power series is raised to the power $x$ include many important special cases, which have surprising properties that are not widely known. This paper explains how to recognize and use such properties, and it closes with a general result about approximating such polynomials asymptotically.

Herbert S. Wilf, Doron Zeilberger

The method of rational function certification for proving terminating hypergeometric identities is extended from single sums or integrals to multi-integral/sums and ``$q$&#39;&#39; integral/sums.

John Martino, Stewart Priddy

We give a classification of the $p$--local stable homotopy type of $BG$, where $G$ is a finite group, in purely algebraic terms. $BG$ is determined by conjugacy classes of homomorphisms from $p$--groups into $G$. This classification greatly simplifies if $G$ has a normal Sylow $p$--subgroup; the stable homotopy types then depends only on the Weyl group of th

Samuel L. Krushkal

We describe briefly a new approach to some problems related to Teichmüller spaces, invariant metrics, and extremal quasiconformal maps. This approach is based on the properties of plurisubharmonic functions, especially of the plurisubharmonic Green function. The main theorem gives an explicit representation of the Green function for Teichmüller spaces by the

Carolyn Gordon, David L. Webb, Scott Wolpert

We use an extension of Sunada&#39;s theorem to construct a nonisometric pair of isospectral simply connected domains in the Euclidean plane, thus answering negatively Kac&#39;s question, ``can one hear the shape of a drum?&#39;&#39; In order to construct simply connected examples, we exploit the observation that an orbifold whose underlying space is a simply

Alexandre Erëmenko

A ``self--similar&#39;&#39; example is constructed that shows that a conjecture of N. U. Arakelyan on the order of decrease of deficiencies of an entire function of finite order is not true.

Ewa Damek, Fulvio Ricci

Certain solvable extensions of $H$-type groups provide noncompact counterexamples to the so-called Lichnerowicz conjecture, which asserted that ``harmonic&#39;&#39; Riemannian spaces must be rank 1 symmetric spaces.

Michael G. Crandall, Hitoshi Ishii, Pierre-Louis Lions

The notion of viscosity solutions of scalar fully nonlinear partial differential equations of second order provides a framework in which startling comparison and uniqueness theorems, existence theorems, and theorems about continuous dependence may now be proved by very efficient and striking arguments. The range of important applications of these results is

Ara Basmajian

We discuss two generalizations of the collar lemma. The first is the stable neighborhood theorem which says that a (not necessarily simple) closed geodesic in a hyperbolic surface has a \lq\lq stable neighborhood\rq\rq whose width only depends on the length of the geodesic. As an application, we show that there is a lower bound for the length of a closed geo

Shreeram S. Abhyankar

The author surveys Galois theory of function fields with non-zero caracteristic and its relation to the structure of finite permutation groups and matrix groups.

Andreas Cap, Andreas Kriegl, Peter W. Michor, Jiři Vanžura

We carry over to a quite general noncommutative setting some of the basic tools of differential geometry, using from the very beginning the setting of convenient vector spaces developed by Froelicher and Kriegl, which allows to carry all of multilinear algebra into this kind of functional analysis with suitably completed tensor products. In the first section

Eduardo Fradkin, Enrique Moreno, Fidel A. Schaposnik

We use path-\-integral methods to derive the ground state wave functions of a number of two-\-dimensional fermion field theories and related systems in one-\-dimensional many body physics. We derive the exact wave function for the Thirring/Luttinger and Coset fermion models and apply our results to derive the universal behavior of the wave functions of the H

M. A. R. Osorio, M. A. Vazquez-Mozo

We study the implications of duality symmetry on the analyticity properties of the partition function as it depends upon the compactification length. In order to obtain non-trivial compactifications, we give a physical prescription to get the Helmholtz free energy for any heterotic string supersymmetric or not. After proving that the free energy is always in

I. Tsutsui, L. Feher

We develop a phase space path-integral approach for deriving the Lagrangian realization of the models defined by Hamiltonian reduction of the WZNW theory. We illustrate the uses of the approach by applying it to the models of non-Abelian chiral bosons, $W$-algebras and the GKO coset construction, and show that the well-known Sonnenschein&#39;s action, the ge

Paul Langacker

The XXVII$^{\rm th}$ Rencontres de Moriond featured approximately 84 talks on a wide range of topics. I will try to summarize the highlights under the hypothesis that $SU_3 \x SU_2 \x U_1$ is correct to first approximation, concentrating on probes for new physics at various scales.

M. Caselle, R. Fiore, F. Gliozzi, S. Vinti

We report on a high precision Montecarlo test of the three dimensional Ising gauge model at finite temperature. The string tension $σ$ is extracted from the expectation values of correlations of Polyakov lines. Agreement with the string tension extracted from Wilson loops is found only if the quantum fluctuations of the flux tube are properly taken into acco

Donald E. Knuth, Arvind Raghunathan

The purpose of this note is to attach a name to a natural class of combinatorial problems and to point out that this class includes many important special cases. We also show that a simple problem of placing nonoverlapping labels on a rectangular map is NP-complete.