December 1992 arXiv papers — page 2

Ruy Exel

The field of C*-algebras over the interval [0,2] for which the fibers are the Soft Tori is shown to be continuous. This result is applied to show that any pair of non-commuting unitary operators can be perturbed (in a weak sense) in such a way to decrease the commutator norm. Perturbations in norm are also considered and a characterization is given for pairs

H. Lu, C. N. Pope, S. Schrans, X. J. Wang

We present a procedure for computing gauge-invariant scattering amplitudes in the $W_3$ string, and use it to calculate three-point and four-point functions. We show that non-vanishing scattering amplitudes necessarily involve external physical states with excitations of ghosts as well as matter fields. The crossing properties of the four-point functions are

Bin Shao, Niels R. Walet, R. D. Amado

We examine the dynamics of a baryon number zero lump in the Skyrme picture, as a model for annihilation in the $\bar{N}N$ system. We find that radiation propagates at the causal limit as a localized pulse and that the linearized theory gives a good approximation. Both of these results are contrary to findings in the Sine-Gordon model.

Daniel S. Freed

We derive (quasi-)quantum groups in 2+1 dimensional topological field theory directly from the classical action and the path integral. Detailed computations are carried out for the Chern-Simons theory with finite gauge group. The principles behind our computations are presumably more general. We extend the classical action in a d+1 dimensional topological th

B Gato-Rivera, A M Semikhatov

We use the Kontsevich-Miwa transform to relate the different pictures describing matter coupled to topological gravity in two dimensions: topological theories, Virasoro constraints on integrable hierarchies, and a DDK-type formalism. With the help of the Kontsevich-Miwa transform, we solve the Virasoro constraints on the KP hierarchy in terms of minimal mode

Michael Martin Nieto

This article reports on a program to obtain and understand coherent states for general systems. Most recently this has included supersymmetric systems. A byproduct of this work has been studies of squeezed and supersqueezed states. To obtain a physical understanding of these systems has always been a primary goal. In particular, in the work on supersymmetry

Marek Karliner, Alexander Migdal, Boris Rusakov

We compute the exact spectral density of random matrices in the ground state of the quantum hamiltonian corresponding to the matrix model whose double scaling limit describes pure gravity in 2D. We show that the non-perturbative effects are very large and in certain cases dominate the semi-classical WKB contribution studied in the earlier literature. The phy

A. Brandhuber, M. Langer, M. Schweda, O. Piguet

The topological supersymmetry of the pure Chern-Simons model in three dimensions is established in the case where the theory is defined in the axial gauge.

Martin Cederwall

Massless particle dynamics in $D=10$ Minkowski space is given an $E_7$-covariant formulation, including both space-time and twistor variables. $E_7$ contains the conformal algebra as a subalgebra. Analogous constructions apply to $D=3,4$ and 6.

P. Rama Devi, T. R. Govindarajan, R. K. Kaul

Chern-Simons field theory based on a compact non-abelian gauge group is studied as a theory of knots and links in three dimensions. A method to obtain the invariants for links made from braids of upto four strands is developed. This generalizes our earlier work on $SU(2)$ Chern-Simons theory.

Sergio Fanchiotti, Bernd Kniehl, Alberto Sirlin

We study the incorporation of QCD effects in the basic electroweak corrections \drcar, \drcarw, and \dr. They include perturbative \Ord{αα_s} contributions and $t\bar{t}$ threshold effects. The latter are studied in the resonance and Green-function approaches, in the framework of dispersion relations that automatically satisfy relevant Ward identities. Refin

Daniel Ng

An electroweak model of SU(3) $\times$ U(1) gauge group is studied. {}From the group theoretical constraint, the symmetry breaking of this model to the standard model occurs at 1.7~TeV or lower. Hence the mass of the new neutral gauge boson is less than 1.7 TeV. The $Y^\pm$ and $Y^{\pm\pm}$ masses are found to be less than half of the $Z_2$ mass. Thus, the d

Michael Martin Nieto

In an historical context, present limits on the photon rest mass are reviewed. More stringent, yet speculative, limits which have been proposed are mentioned. Finally, new theoretical ideas and possible experimental improvements on the present limits are discussed, along with possible relationships between these two areas.

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

We study the constraints on masses and mixing angles imposed by the measured $Z^0$ invisible width, in a model in which a singlet right-handed neutrino mixes with all the Standard Model neutrinos.

Jose W. F. Valle

INVITED TALK AT SECOND WORKSHOP ON TAU LEPTON PHYSICS, COLOMBUS, OHIO, SEPTEMBER 1992

E. N. Argyres, C. G. Papadopoulos, R. Kleiss

The occurrence of zeros of 2 to n amplitudes at threshold in scalar theories is studied. We find a differential equation for the scalar potential, which incorporates all known cases where the 2 to n amplitudes at threshold vanish for all sufficiently large $n$, in all space-time dimensions, $d\ge 1$. This equation is related to the reflectionless potentials

Serge Rudaz, Ajit M. Srivastava

We examine the basic assumptions underlying a scenario due to Kibble that is widely used to estimate the production of topological defects. We argue that one of the crucial assumptions, namely the geodesic rule, although completely valid for global defects, becomes ill defined for the case of gauged defects. We address the issues involved in formulating a su

Wolfgang Bock, Christoph Frick, Jan Smit, Jeroen C. Vink

We present results for the renormalized quartic self-coupling $λ_R$ and the Yukawa coupling $y_R$ in a lattice fermion-Higgs model with two SU(2)$_L$ doublets, mostly for large values of the bare couplings. One-component (`reduced') staggered fermions are used in a numerical simulation with the Hybrid Monte Carlo algorithm. The fermion and Higgs masses a

C. H. Llewellyn Smith, N. J. Watson

It is shown how to adapt the non-perturbative coupled cluster method of many-body theory so that it may be successfully applied to Hamiltonian lattice $SU(N)$ gauge theories. The procedure involves first writing the wavefunctions for the vacuum and excited states in terms of linked clusters of gauge invariant excitations of the strong coupling vacuum. The fu

A. K. De, E. Focht, W. Franzki, J. Jersak

We present numerical evidence that the 2d Yukawa models with strong quartic selfcoupling of the scalar field have the same phase structure and are asymptotically free in the Yukawa coupling like the Gross-Neveu models.

A. K. Bukenov, A. V. Pochinsky, M. I. Polikarpov, L. Polley

We develop a formalism for the quantization of topologically stable excitations in the 4-dimensional abelian lattice gauge theory. The excitations are global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The operators of creation and annihilation of string states are constructed; the string Green functions are represented as a path integral ove

P. Hasenfratz, F. Niedermayer

The low temperature and large volume effects in the d=2+1 antiferromagnetic quantum Heisenberg model are dominated by magnon excitations. The leading and next-to-leading corrections are fully controlled by three physical constants, the spin stiffness, the spin wave velocity and the staggered magnetization. Among others, the free energy, the ground state ener

C. Klimčík, P. Kolník

A large class of solutions of the Einstein-conformal scalar equations in D=2+1 and D=3+1 is identified. They describe the collisions of asymptotic conformal scalar waves and are generated from Einstein-minimally coupled scalar spacetimes via a (generalized) Bekenstein transformation. Particular emphasis is given to the study of the global properties and the

Alan Hopenwasser, Cecelia Laurie

This paper studies direct limits of full upper triangular matrix algebras with embeddings which are not *-extendible. A representation of the limit algebra is found so that the generated C*-algebra is the C*-envelope. Some examples are described.

Bill Sutherland, B. Sriram Shastry

In this paper, we investigate a family of one-dimensional multi-component quantum many-body systems. The interaction is an exchange interaction based on the familiar family of integrable systems which includes the inverse square potential. We show these systems to be integrable, and exploit this integrability to completely determine the spectrum including de

Jinwu Ye, Subir Sachdev, N. Read

We examine a model of $M$-component quantum rotors coupled by Gaussian-distributed random, infinite-range exchange interactions. A complete solution is obtained at $M=\infty$ in the spin-glass and quantum-disordered phases. The quantum phase transition separating them is found to possess logarithmic violations of scaling, with no further modifications to the

B. Holdom, M. Sutherland

Effects associated with hyperfine mass splitting between pseudo\-scalar and vector mesons may induce surprisingly large $1/{m}_{Q}^{2}$ corrections in the heavy quark expansion. We demonstrate this in a relativistic quark model by calculating to all orders in $1/{m}_{Q}$, with and without hyperfine effects, and comparing to the first order results. Total cor

C. M. Chen, D. J. Ernst, M. B. Johnson

Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order potential includes:\ \ (1)~full Fermi--averaging integration including both the delta propagation and the intrinsic nonloc

C. M. Chen, D. J. Ernst, M. B. Johnson

We investigate theoretical approaches to pion--nucleus elastic scattering at high energies (300 $\le T_π\le$ 1 GeV). A ``model--exact'' calculation of the lowest--order microscopic optical model, carried out in momentum space and including the full Fermi averaging integration, a realistic off--shell pion--nucleon scattering amplitude and fully covari

A. Bianconi, S. Boffi, D. E. Kharzeev

The dynamics of nuclear transparency in hard nuclear reactions is studied by an expansion of the correlator of the hard scattering operator on a hadronic basis. Colour transparency appears as an effect of interference between the amplitudes corresponding to the final state interaction of different intermediate baryonic states. We find that colour transparenc

L. R. Dodd, D. E. Driscoll

Pionic contributions to static nucleon properties are calculated in a chiral extension of the colour-dielectric model. The pion field and residual gluon field are treated perturbatively. It is shown that with a simple choice for the energy of the scalar confining field and in the chiral limit, the system of equations describing the bare soliton and the pertu

Jean-Loup Gervais

These lecture notes review current progress on the class of conformal theories which may be studied by quantizing the conformal Toda dynamics. After summarizing recent developments in undertanding the quantum group structure of the Liouville theory, one recalls how classically, two-dimensional black holes come out from the non-abelian Toda systems, and revie

P. Di Francesco, C. Itzykson

We study a generating function for the sum over fatgraphs with specified valences of vertices and faces, inversely weighted by the order of their symmetry group. A compact expression is found for general (i.e. non necessarily connected) fatgraphs. This expression admits a matrix integral representation which enables to perform semi--classical computations, l

A. Fring

We present a systematic derivation for a general formula for the n-point coupling constant valid for affine Toda theories related to any simple Lie algebra {\bf g}. All n-point couplings with $n \geq 4$ are completely determined in terms of the masses and the three-point couplings. A general fusing rule, formulated in the root space of the Lie algebra, is de

F. David

The most general large N eigenvalues distribution for the one matrix model is shown to consist of tree-like structures in the complex plane. For the m=2 critical point, such a split solution describes the strong coupling phase of 2d quantum gravity (c=0 non-critical string). It is obtained by taking combinations of complex contours in the matrix integral, an

G. Falqui, C. -M. Viallet

We investigate global properties of the mappings entering the description of symmetries of integrable spin and vertex models, by exploiting their nature of birational transformations of projective spaces. We give an algorithmic analysis of the structure of invariants of such mappings. We discuss some characteristic conditions for their (quasi)--integrability

K. Hornfeck

We show that that the Jacobi-identities for a W-algebra with primary fields of dimensions 3, 4 and 5 allow two different solutions. The first solution can be identified with WA_4. The second is special in the sense that, even though associative for general value of the central charge, null-fields appear that violate some of the Jacobi-identities, a fact that

Kanehisa Takasaki

Recently Strachan introduced a Moyal algebraic deformation of selfdual gravity, replacing a Poisson bracket of the Plebanski equation by a Moyal bracket. The dressing operator method in soliton theory can be extended to this Moyal algebraic deformation of selfdual gravity. Dressing operators are defined as Laurent series with coefficients in the Moyal (or st

Miriam Leurer, Yosef Nir, Nathan Seiberg

It is possible that the hierarchy in the masses and mixing of quarks is a result of a horizontal symmetry. The smallness of various parameters is related to their suppression by high powers of a scale of new physics. We analyze in detail the structure of such symmetries in view of new experimental data and present explicit models consistent with all phenomen

A. Barducci, R. Casalbuoni, G. Pettini, R. Gatto

A first order phase transition leading to deconfinement and chiral restoration is a likely possibility for QCD, at least in some region of the temperature-density plane. A signal for a unique transition is that the order parameters for such transitions (which can be understood in terms of symmetries only in limiting situations of very massive or massless qua

S. Yu. Khlebnikov, R. D. Peccei

In preon models based on chiral gauge theories, we show that light composite fermions can ensue as a result of gauging a subset of preons in a vector-like manner. After demonstrating how this mechanism works in a toy example, we construct a one generation model of quarks which admits a hierarchy between the up and down quark masses as well as between these m

Peter Cho

The effects of the CP violating $θ$ term in the QCD Lagrangian upon low energy hadronic phenomenology are reconsidered. Strong CP violating interactions among Goldstone bosons and octet baryons are incorporated into an effective chiral Lagrangian framework. The $θ$ term's impact upon the decays $η\toππ$ and $π^0\toγγ$ is then investigated but found to be

Thomas Kalkreuter

NOTE: this is a shortened version of the abstract of the paper. Multigrid methods for propagators in gauge fields are investigated. Gauge fields are incorporated in algorithms in a covariant way. This avoids the necessity for gauge fixing in computations of propagators. The kernel $C$ of the restriction operator which averages from one grid to the next coars

V. Azcoiti, G. Di Carlo, A. F. Grillo

We study the $β, N$ critical behaviour of non compact QED with $N$ species of light fermions, using a method we have proposed for unquenched simulations. We find that there exist two phase transition lines: one, second order, and the other, first order, that approaches asymptotically the $β=0$ axis. These two lines have different physical origin, the second

Jan Hemmingsson, Hans J. Herrmann

We investigate cellular automata where some global quantity varies periodically or quasiperiodically with time. We find that these systems are highly predictable, and can be rather well described by a set of mean-field variables. We conclude that this is not a collective phenomenon - where different subsystems are supposed to synchronize - but rather like ma

Daijiro Yoshioka

A model system is considered where two dimensional electrons are confined by a harmonic potential in one direction, and are free in the other direction. Ground state in strong magnetic fields is investigated through numerical diagonalization of the Hamiltonian. It is shown that the fractional quantum Hall states are realized even in the presence of the exter

V. Pleitez

We comment a model based on the $SU(3)_c \otimes SU(3)_L \otimes U(1)_X$ gauge symmetry recently proposed by Frampton. We stressed that the analysis of flavor changing neutral currents impose strong constraints on th emasses of the new gauge bosons of the model.

A. Rapisarda

Cross section fluctuations in nuclear scattering are briefly reviewed in order to show the main important features. Then chaotic scattering is introduced by means of a very simple model. It is shown that chaoticity produces the same kind of irregular fluctuations observed in light heavy--ion collisions. The transition from order to chaos allows a new general

F. David, B. Duplantier, E. Guitter

We consider a model of D-dimensional tethered manifold interacting by excluded volume in R^d with a single point. By use of intrinsic distance geometry, we first provide a rigorous definition of the analytic continuation of its perturbative expansion for arbitrary D, 0 < D < 2. We then construct explicitly a renormalization operation, ensuring renormalizabil

Sebastian Sachse

Replacing the continuous space by a cubic lattice we find a deformation of the Poincaré algebra. A deformation of the relativistic mass operator is shown to be a Casimir of the algebra. The real structure is preserved.

Timothy J. Hollowood, J. Luis Miramontes

The problem of interpreting a set of ${\cal W}$-algebra constraints constructed in terms of an arbitrarily twisted scalar field as the recursion relations of a topological theory is addressed. In this picture, the conventional models of topological gravity coupled to $A$, $D$ or $E$ topological matter, correspond to taking the scalar field twisted by the Cox

K. Behrndt

We investigate the tachyon coupling in a static Robertson--Walker like metric background. For a tachyon and dilaton field which are only time dependent one can rewrite this model as a SU(2) Wess--Zumino--Witten model and a scalar Feigin--Fuchs theory. In this case the restriction to a real exponential tachyon field fixes the level $k$ of the Wess--Zumino--Wi

Jean-Pierre Ader, Hamid Kachkachi

A consistent method for obtaining a well-defined Polyakov action on the supertorus is presented. This method uses the covariantization of derivative operators and enables us to construct a Polyakov action which is globally defined.

A. A. Bytsenko, E. Elizalde, S. D. Odintsov, S. Zerbini

Using a Laurent series representation for the (super)string one-loop free energy, an explicit form for the analytic continuation of the Laurent series beyond the critical (Hagedorn) temperature is obtained. As an additional result, a periodic structure is found in (super)string thermodynamics. A brief physical discussion about the origin and meaning of such

E. Elizalde, S. Leseduarte, A. Romeo

We study the sum $\dsζ_H(s)=\sum_j E_j^{-s}$ over the eigenvalues $E_j$ of the Schrdinger equation in a spherical domain with Dirichlet walls, threaded by a line of magnetic flux. Rather than using Green&#39;s function techniques, we tackle the mathematically nontrivial problem of finding exact sum rules for the zeros of Bessel functions $J_ν$, which are ext

N. Mohammedi

We show that the gauged SL(2,R) WZWN model yields arbitrary spacetimes in two dimensions. The c = 1 matter field and the black hole singularity are just two particular cases in these spacetimes.

Edward Frenkel, Andras Szenes

We give a new proof of the dilogarithm identities, associated to the (2,2n+1) minimal models of the Virasoro algebra.

H. A. Riggs, H. J. Schnitzer

We argue that the large-$\Nc$ behaviour of the Yukawa couplings in the Skyrme model involves issues more subtle than the vanishing of linear fluctuations needed for classical stability of the skyrmion. The chiral fluctuations about the skyrmion must be quantized in order to reach a conclusion. An improved quantization procedure allows us to confront this que

Robert Garisto, John N. Ng

We consider the 4 $γγll$ ($l=μ,\ e$) events reported by the L3 collaboration, and go through the logical possibilities which could explain the events. If they are not coincidental bremsstrahlung events, we find that the physics which they could point to is extremely limited. One possibility would be to have a new 60 GeV scalar (or pseudoscalar) particle $X^0

J. C. Montero, F. Pisano, V. Pleitez

We study the Glashow-Iliopoulos-Maiani mechanism for flavor-changing-neutral-currents suppression in both, the gauge and Higgs sectors, for models with $SU(3)_L\otimes U(1)_N$ gauge symmetry. The models differ one from the other only with respect to the representation content. The main features of these models are that in order to cancel the triangle anomali

Vittorio Del Duca

Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons.

Carsten Grosse-Knetter, Reinhart Koegerler

Within the framework of the path-integral formalism we reinvestigate the different methods of removing the unphysical degrees of freedom from spontanously broken gauge theories. These are: construction of the unitary gauge by gauge fixing; \rx -limiting procedure; decoupling of the unphysical fields by point transformations. In the unitary gauge there exists

M. Neubert, Z. Ligeti, Y. Nir

We calculate the contributions arising at order $α_s$ in the QCD sum rule for the spin-symmetry violating universal function $χ_3(v\cdot v&#39;)$, which appears at order $1/m_Q$ in the heavy quark expansion of meson form factors. In particular, we derive the two-loop perturbative contribution to the sum rule. Over the kinematic range accessible in $B\to D^{(

Marcos Rosenbaum, Michael P. Ryan, Sukanya Sinha

We consider the quantum evolution of the space-independent mode of a $λϕ^4$ theory as a minisuperspace in the space of all $ϕ$. The motion of the wave packet in the minisuperspace is then compared to the motion of a wave packet in a larger minisuperspace consisting of the original minisuperspace plus one space-dependent mode. By comparing the motion of the t

Peter Ossadnik

We measure the multiscaling behavior of large off-lattice diffusion limited aggregates (DLA). In contrast to previous studies we now find a continuous dependence of the multiscaling dimensions $D(x)$ on the relative distance $x=r/R_g$ to the center of the cluster. This result agrees with measurements on smaller clusters. Furthermore we report the multiscalin

T. Ala-Nissila, T. Hjelt, J. M. Kosterlitz, O. Venäläinen

We discuss the results of extensive numerical simulations in order to estimate the scaling exponents associated with kinetic roughening in higher dimensions, up to d=7+1. To this end, we study the restricted solid - on - solid growth model, for which we employ a novel fitting {\it ansatz} for the spatially averaged height correlation function $\bar G(t) \sim

Paul J. Steinhardt

Extended inflation is a promising new approach to implementing the inflationary universe scenario. This paper reviews recent advances including a new, more robust mechanism for ending extended inflation, a new prediction for the density fluctuation spectrum generated by extended inflation, and the discovery that extended inflation can produce gravitational w

George F. Smoot, Paul J. Steinhardt

Could COBE DMR be detecting the imprint from a spectrum of gravitational waves generated during inflation? The conventional inflationary prediction had been that the cosmic microwave anisotropy is dominated by energy density fluctuations generated during inflation and that the gravitational waves contribute negligibly. In this paper, we report on recent work

U. Ellwanger, L. Vergara

The flow equations or exact RG equations for the Higgs Top System are solved to leading order in $1/N_c$. This allows to relate arbitrary bare actions with this field content continuously to effective low energy theories, and we find the flow converging towards general renormalizable models. The assumption of a bare action of the generalized Nambu-Jona-Lasin

B. Rusakov

The partition function of a two-dimensional quantum gauge theory in the large-$N$ limit is expressed as the functional integral over some scalar field. The large-$N$ saddle point equation is presented and solved. The free energy is calculated as the function of the area and of the Euler characteristic. There is no non-trivial saddle point at genus $g>0$. The

T. Barnes, E. S. Swanson

We derive closed form kaon-nucleon scattering amplitudes using the ``quark Born diagram&#34; formalism, which describes the scattering as a single interaction (here the OGE spin-spin term) followed by quark line rearrangement. The low energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with experiment given conventional quark model par

Bruno Zumino

A review of recent developments in the quantum differential calculus. The quantum group $GL_q(n)$ is treated by considering it as a particular quantum space. Functions on $SL_q(n)$ are defined as a subclass of functions on $GL_q(n)$. The case of $SO_q(n)$ is also briefly considered. These notes cover part of a lecture given at the XIX International Conferenc

E. Sezgin

Chiral/self-dual restrictions of various super Yang-Mills and supergravity theories in (2,2) dimensions are described. These include the N=1 supergravity with a cosmological term and the N=1 new minimal supergravity theory. In the latter case, a self-duality condition on a torsionful Riemann curvature is possible, and it implies the equations of motion that

C. R. Hagen

It is shown that a model recently proposed for numerical calculations of bound states in QED$_3$ is in fact an improper truncation of the Aharonov-Bohm potential.

L. Ibanez, D. Luest

We discuss the relationship between target space modular invariance and discrete gauge symmetries in four-dimensional orbifold-like strings. First we derive the modular transformation properties of various string vertex operators of the massless string fields. Then we find that for supersymmetric compactifications the action of the duality elements, leaving

G. K. Leontaris, N. D. Tracas

We reexamine a succesful fermion mass Ansatz proposed by Giudice for a wide range of the ratio $tanβ=\frac {<\bar h>}{<h>}$ (where ${\bar h},h$ are the two standard higgs fields), in the context of supersymmetric grand unified theories. We find that the 7 predictions of the ansatz, $V_{us}, V_{cb}, V_{ub}, m_u, m_d, m_s$ and $m_b$ are in good agreement with

T. Altherr, E. Petitgirard, T. del Rio Gaztelurrutia

Using thermal field theory, we derive simple analytic expressions for the spectral density of photons in degenerate QED plasmas, without assuming the usual non or ultra-relativistic limit. We recover the standard results in both cases. Although very similar in ultra-relativistic plasmas, transverse and longitudinal excitations behave very differently as the

E. R. Nakamura, K. Kudo, T. Hashimoto, I. Yoneda

On the basis of a lattice gas model and the convolution formula with cell construction scheme, we demonstrate that intermittency in the rapidity-space with respect to the scaled moments comes from a phase transition between ordered phase and disordered phase. It is pointed out that as concerns the power-law behavior of the moments the critical exponent depen

Rajamani Narayanan, Herbert Neuberger

We show that two recent independent proposals for regularizing a chiral gauge theory stem from one common trick. If the anomaly free complex representation carried by the right handed fermi--fields is $r$ one constructs a vector like theory with flavored right handed fermionic matter in $r+\bar r$ but with a mass matrix of the order of the cutoff and having

A. Casher, F. Englert

The tunneling approach for entropy generation in quantum gravity is applied to black holes. The area entropy is recovered and shown to count only a tiny fraction of the black hole degeneracy. The latter stems from the extension of the wave function outside the barrier. In fact the semi-classical analysis leads to infinite degeneracy. Evaporating black holes

F. Guinea, J. Gonzalez, M. A. H. Vozmediano

The electron-phonon and Coulomb interactions inC$_{60}$, and larger fullerene spheres are analyzed. The coupling between electrons and intramolecular vibrations give corrections $\sim 1 - 10$ meV to the electronic energies for C$_{60}$, and scales as $R^{-4}$ in larger molecules. The energies associated with electrostatic interactions are of order $\sim 1 -

Rudolf A. Römer, Bill Sutherland

We numerically study the momentum distribution of one-dimensional Bose and Fermi systems with long-range interaction $g/r^2$ for the ``special&#39;&#39; values $g= -\frac{1}{2}, 0, 4$, singled out by random matrix theory. The critical exponents are shown to be independent of density and in excellent agreement with estimates obtained from $c=1$ conformal fini

M. J. Bergvelt, A. P. E. ten Kroode

For every partition of a positive integer $n$ in $k$ parts and every point of an infinite Grassmannian we obtain a solution of the $k$ component differential-difference KP hierarchy and a corresponding Baker function. A partition of $n$ also determines a vertex operator construction of the fundamental representations of the infinite matrix algebra $gl_\infty

J. G. Congleton

It is shown that the 1S level hyperfine populations prior to muon capture will be statistical when either target or beam are unpolarised independent of the atomic level at which the hyperfine interaction becomes appreciable. This assertion holds in the absence of magnetic transitions during the cascade and is true because of minimal polarisation after atomic

M. Matsuo, T. Døssing, B. Herskind, S. Frauendorf

Fluctuations associated with stretched E2 transitions from high spin levels in nuclei around $^{168}$Yb are investigated by a cranked shell model extended to include residual two-body interactions. It is found that the gamma-ray energies behave like random variables and the energy spectra show the Poisson fluctuation, in the cranked mean field model without

M. Matsuo, T. Døssing, E. Vigezzi, R. A. Broglia

The rotational spectrum of $^{168}$Yb is calculated diagonalizing different effective interactions within the basis of unperturbed rotational bands provided by the cranked shell model. A transition between order and chaos taking place in the energy region between 1 and 2 MeV above the yrast line is observed, associated with the onset of rotational damping. I

E. V. Shuryak, J. J. M. Verbaarschot

We construct a random matrix model that, in the large $N$ limit, reduces to the low energy limit of the QCD partition function put forward by Leutwyler and Smilga. This equivalence holds for an arbitrary number of flavors and any value of the QCD vacuum angle. In this model, moments of the inverse squares of the eigenvalues of the Dirac operator obey sum rul

H. Aratyn, C. P. Constantinidis, L. A. Ferreira, J. F. Gomes

We use Hirota&#39;s method formulated as a recursive scheme to construct complete set of soliton solutions for the affine Toda field theory based on an arbitrary Lie algebra. Our solutions include a new class of solitons connected with two different type of degeneracies encountered in the Hirota&#39;s perturbation approach. We also derive an universal mass f

Michael B. Green

This paper considers interactions between closed strings and open strings satisfying either Neumann or constant (point-like) Dirichlet boundary conditions in a BRST formalism in the critical dimension. With Neumann conditions this reproduces the well-known stringy version of the Higgs mechanism. With Dirichlet conditions the open-string states correspond to

Anatol N. Kirillov

We show that the coefficients of decomposition into an irreducible components of the tensor powers of level $r$ symmetric algebra of adjoint representation coincide with the Verlinder numbers. Also we construct (for $sl(2)) the representations of a general linear group those dimensions are given by corresponding Verlinde&#39;s numbers.

John Bahcall

Contents: 1. The Conference 2. Solar Neutrinos -A. Operating Experiments -B. New Funded Experiments -C. Are Solar Neutrino Fluxes Time Dependent? -D. Have $pp$ Neutrinos Been Detected? -E. Is Directionality Required for Astronomical Observations? -F. Is There a Solar Neutrino Problem? -G. What Have We Learned? 3. Supernova Neutrinos 4. Atmospheric Neutrinos

M. A. Doncheski, J. L. Hewett

We study the effects of virtual leptoquark exchange on charged current and neutral current processes at HERA, on di-lepton production at the Tevatron, and on quark pair production at LEP II. We present the areas of parameter space that can be excluded at these colliders by searching for deviations from Standard Model expectations.

J. L. Hewett

We present the bounds that can be obtained on the charged Higgs sector in two-Higgs-Doublet Models from measurements at LEP of the decay $B\to Dτν$, and from searches by CLEO for the inclusive decay $b\to sγ$.

P. K. Mohapatra Pages 9 COLO-HEP-271

We propose a way to differentiate between various extra $U(1)$ models using flavor tagging in the decay modes $Z^{\prime}\rightarrow q{\bar{q}}$ once the extra $Z^{\prime}$ is observed at future colliders in the lepton channel. A generalization of the R parameter, namely, one for charge $\frac{1}{3}$ and one for charge $\frac{2}{3}$ quark gives a two paramet

P. K. Mohapatra

We investigate the effect of a possible large frozen-in magnetic field in the core of the sun and a neutrino magnetic moment of the order of $10^{-10}$ Bohr magneton on the MSW parameters. Such a possibility can completely depolarize the $ν_{eL}$ resulting in a factor of half of the emitted number. This in combination with MSW can explain the present experim

Véronique Bernard, Norbert Kaiser, Ulf-G. Meißner

We investigate the momentum dependence of the extended Drell-Hearn-Gerasimov sum rule. An economical formalism is developed which allows to express the extended DHG sum rule in terms of a single virtual Compton amplitude in forward direction. Rigorous results for the small momentum evolution are derived from chiral perturbation theory within the one-loop app

K. Sridhar

The process AB --> Quarkonium + photon + X, for a heavy quarkonium state such as J/psi or Upsilon, is considered. The ratio of the cross-sections for this process in pp and pp(bar) collisions is shown to be a vary sensitive probe of models of quarkonium formation.

Paul B. Mackenzie

Lattice calculations of heavy quark systems provide very good measures of the lattice spacing, a key element in recent determinations of the strong coupling constant using lattice methods. They also provide excellent testing grounds for lattice methods in general. I review recent phenomenological and technical developments in this field.

A. D. Kennedy

I present a summary of recent algorithmic developments for lattice field theories. In particular I give a pedagogical introduction to the new Multicanonical algorithm, and discuss the relation between the Hybrid Overrelaxation and Hybrid Monte Carlo algorithms. I also attempt to clarify the role of the dynamical critical exponent z and its connection with `c

Peter C. Aichelburg, Piotr Bizon

We study magnetically charged black holes in the Einstein-Yang-Mills-Higgs theory in the limit of infinitely strong coupling of the Higgs field. Using mixed analytical and numerical methods we give a complete description of static spherically symmetric black hole solutions, both abelian and nonabelian. In particular, we find a new class of extremal nonabelia