July 1993 arXiv papers — page 2

Peter Cho, Elizabeth Simmons

The impact of nonrenormalizable gluon operators upon inclusive jet cross sections is studied. Such operators could arise in an effective strong interaction Lagrangian from gluon substructure and would induce observable cross section deviations from pure QCD at high transverse jet energies. Comparison of the theoretical predictions with recent CDF data yields

R. Bönisch

The scalar interaction term of the top mode standard model can be generated by a gauge theory. It is emphasized that in this approach generalization to family space directly yields a heavy top quark while leaving all other quarks massless. By generating the new interaction from gauge extension to custodial $SU(2)$, the standard model bound $m_{top} \stackrel

Marc Sher

In the standard model, a lower bound to the Higgs mass (for a given top quark mass) exists if one requires that the standard model vacuum be stable. This bound is calculated as precisely as possible, including the most recent values of the gauge couplings, corrected two-loop beta functions and radiative corrections to the Higgs and top masses. In addition to

Gideon Lana

We calculate the two-body interaction of spherical hadronic bubbles immersed in a gluon plasma at temperatures above the phase transition. Modeling the bubbles with the MIT bag we find that the two body potential is repulsive for all bubble-bubble distances considered. This implies that a static configuration of spherical hadronic bubbles in a gluon backgrou

A. C. Bawa, K. Charchula, W. J. Stirling

The photoproduction of Drell-Yan lepton pairs at HERA is studied. We show that in the backward rapidity region the cross section is strongly sensitive to the small-$x$ behaviour of the quark distributions in the proton, and that with sufficient luminosity it should be possible to distinguish singular $xq \sim x^{-1/2}$ behaviour from standard Regge $xq \sim

O. Diego, J. Gonzalez, J. Salas

We study, using dimer and Monte Carlo approaches, the critical properties and finite size effects of the Ising model on honeycomb lattices folded on the tetrahedron. We show that the main critical exponents are not affected by the presence of conical singularities. The finite size scaling of the position of the maxima of the specific heat does not match, how

Ying-Hong Li, S. Teitel

Monte Carlo simulations of the uniformly frustrated 3d XY model are used to model vortex line fluctuations in high temperature superconductors in an applied magnetic field. We find two distinct phase transitions. At a lower T_{c\perp}, the vortex lattice melts and coherence is lost in planes perpendicular to the magnetic field. At a higher T_{cz}, a vortex t

D. M. Deaven, D. S. Rokhsar, A. Barbieri

We study Gutzwiller-projected variational wavefunctions for charged, spinless holon excitations in chiral spin liquids. We find that these states describe anyons, with a statistical phase $Φ_s$ that is continuously adjustable between $0$ and $π/2$, depending on a variational parameter. The statistical flux attached to each holon is localized to within a latt

A. Csordás, R. Graham, P. Szépfalusy, G. Vattay

One wall of Artin's billiard on the Poincaré half plane is replaced by a one-parameter ($c_p$) family of nongeodetic walls. A brief description of the classical phase space of this system is given. In the quantum domain, the continuousand gradual transition from the Poisson like to GOE level statistics due to the small perturbations breaking the symmetry

L. H. Orr, Yu. L. Dokshitzer, V. A. Khoze, W. J. Stirling

The large width of the top quark influences the way gluons are radiated in top events, giving rise to interesting interference effects in top production and decay. We discuss top width effects in soft guon radiation in $\ee \to \tt$ at high energies and near $\tt$ threshold.

C. P. Burgess, S. Godfrey, H. Konig, D. London

The STU formalism of Peskin and Takeuchi is an elegant method for encoding the measurable effects of new physics which couples to light fermions dominantly through its effects on electroweak boson propagation. However, this formalism cannot handle the case where the scale of new physics is not much larger than the weak scale. In this case three new parameter

C. Greiner, C. Gong, B. Müller

Recently it was pointed out that coherent or condensated states of pions may account for the explanation of the Centauro events observed in cosmic ray showers. We argue that an occurrence of condensed pions requires that the system evolves far out of thermal equilibrium. Besides an unusual charge ratio distribution we show that such a produced state also wou

Marco Bruni, David H. Lyth

This is a somewhat extended version of the original July 93 report. It is proved that the cosmological density perturbation is associated with a peculiar velocity field. This allows a simple formulation of cosmological perturbation theory, which works entirely with quasi-Newtonian fluid flow equations. As an illustration, the large scale cosmic microwave bac

A. Mikovic

We present a review of the canonical quantization approach to the problem of non-perturbative 2d dilaton gravity. In the case of chiral matter we describe a method for solving the constraints by constructing a Kac-Moody current algebra. For the models of interest, the relevant Kac-Moody algebras are based on SL(2,R) X U(1) group and on an extended 2d Poincar

J. P. Doherty, M. A. Moore, J. M. Kim, A. J. Bray

We generalize the KPZ equation to an O(3) $N=2j+1$ component model. In the limit $N \to \infty$ we show that the mode coupling equations become exact. Solving these approximately we find that the dynamic exponent $z$ increases from $3/2$ for $d=1$ to $2$ at the dimension $d\approx3.6$. For $d=1$ it can be shown analytically that $z=3/2$ for all $j$. The case

A. Billoire, T. Neuhaus, B. Berg

We determine the interface free energy $F_{o.d.}$ between disordered and ordered phases in the q=10 and q=20 2-d Potts models using the results of multicanonical Monte Carlo simulations on $L^2$ lattices, and suitable finite volume estimators. Our results, when extrapolated to the infinite volume limit, agree to high precision with recent analytical calculat

Saburo Higuchi, Chigak Itoi, Norisuke Sakai

The renormalization group approach is studied for large $N$ models. The approach of Brézin and Zinn-Justin is explained and examined for matrix models. The validity of the approach is clarified by using the vector model as a similar and simpler example. An exact difference equation is obtained which relates free energies for neighboring values of $N$. The re

K. J. Eskola, Jianwei Qiu, Xin-Nian Wang

We study how much gluon shadowing can be perturbatively generated through the modified QCD evolution in heavy nuclei. The evolution of small-$x$ gluons is investigated within the semiclassical approximation. The method of characteristics is used to evaluate the shadowed distributions in low-$Q$ and small-$x$ region. In solving the modified evolution equation

Daniel Cangemi, Martin Leblanc

We investigate two dimensional supergravity theories, which can be built from a topological and gauge invariant action defined on an ordinary surface. We concentrate on four models. The first model is the $N=1$ supersymmetric extension of Jackiw-Teiltelboim model presented by Chamseddine in a superspace formalism. We complement the proof of Montano, Aoaki, a

George Lavrelashvili, Dieter Maison

We discuss properties and interpretation of recently found globally regular and black hole solutions of a Einstein-Yang-Mills-dilaton theory. Talk given at the 15th annual MRST meeting on High Energy Physics, Syracuse University, NY, May 14-15, 1993.

I. Antoniadis, E. Gava, K. S. Narain, T. R. Taylor

We show that certain type II string amplitudes at genus $g$ are given by the topological partition function $F_g$ discussed recently by Bershadsky, Cecotti, Ooguri and Vafa. These amplitudes give rise to a term in the four-dimensional effective action of the form $\sum_g F_g W^{2g}$, where $W$ is the chiral superfield of $N=2$ supergravitational multiplet. T

J. A. Gracey

We present the formalism for computing the critical exponent corresponding to the $β$-function of the Nambu--Jona-Lasinio model with $SU(M)$ $\times$ $SU(M)$ continuous chiral symmetry at $O(1/N^2)$ in a large $N$ expansion, where $N$ is the number of fermions. We find that the equations can only be solved for the case $M$ $=$ $2$ and subsequently an analyti

G. Barnich, M. Henneaux, R. Tatar

Recent results on the cohomological reformulation of the problem of consistent interactions between gauge fields are illustrated in the case of the Yang-Mills models. By evaluating the local BRST cohomology through descent equation techniques, it is shown (i) that there is a unique local, Poincaré invariant cubic vertex for free gauge vector fields which pre

Fusun Akman

It is typical for a semi-infinite cohomology complex associated with a graded Lie algebra to occur as a vertex operator (or chiral) superalgebra where all the standard operators of cohomology theory, in particular the differential, are modes of vertex operators (fields). Although vertex operator superalgebras -with the inherent Virasoro action- are regarded

T. S. Evans

The zero four-momentum and equal mass limits are taken for the bubble diagram of scalar fields. It is seen that RTF and ITF are in complete agreement. However contributions from this diagram to both retarded and time-ordered functions do depend on the order of the limits and can be infinite in some cases. This shows explicitly that the relation between the f

J. Sirkka, I. Vilja

We compute a unitarity bound for higgs mass using one--loop corrected s--wave partial amplitude for $Z_L Z_L \rightarrow Z_L Z_L$ scattering. We use the equivalence theorem and show that the higgs mass has to be less than $\approx 600$ GeV in order to save the (perturbative) unitarity in the higgs' resonance region. We also discuss about the validity of

D. Zeppenfeld

Low energy (1-loop) constraints on anomalous triple gauge boson vertices (TGV's) are revisited and compared to the sensitivity achievable at LEP II and at future linear $e^+e^-$ colliders. The analysis is performed within the framework of an effective Lagrangian of gauge invariant dimension six operators with the gauge bosons and a single Higgs doublet f

Hai-Yang Cheng

The semileptonic decays $\bar{B}\to D(D^*)π\ell\barν$ are analyzed by heavy quark and chiral symmetries. The branching ratio is of order of a few percent for $\dpi$, but it is much smaller for $\dstar$, of order $10^{-4}-10^{-5}$. The decay mode $B^-\to D^+π^-e^-\barν_e$ provides a nice place for extracting the $D^*Dπ$ coupling constant from the semileptonic

A. A. Bel'kov, A. V. Lanyov, A. Schaale

We derive the effective action for pseudoscalar mesons by integrating out vector and axial--vector collective fields in the generating functional of the bosonized NJL--model. The corresponding modifications of the nonlinear effective Lagrangian and the bosonized currents, arising at $O(p^4)$, are discussed.

Andrew R Liddle

The Cosmic Background Explorer (COBE) detection of microwave background anisotropies may contain a component due to gravitational waves generated by inflation. It is shown that the gravitational waves from inflation might be seen using `beam-in-space' detectors, but not the Laser Interferometer Gravity Wave Observatory (LIGO). The central conclusion, dep

Jysoo Lee, Michael Leibig

It was recently observed that sand flowing down a vertical tube sometimes forms a traveling density pattern in which a number of regions with high density are separated from each other by regions of low density. In this work, we consider this behavior from the point of view of kinetic wave theory. Similar density patterns are found in molecular dynamic simul

Predrag Cvitanović, Per E. Rosenqvist, Gábor Vattay, Hans Henrik Rugh

We investigate a new type of approximation to quantum determinants, the ``\qFd", and test numerically the conjecture that for Axiom A hyperbolic flows such determinants have a larger domain of analyticity and better convergence than the \qS s derived from the \Gt. The conjecture is supported by numerical investigations of the 3-disk repeller, a normal-fo

Predrag Cvitanović, Gábor Vattay

Proofs that Fredholm determinants of transfer operators for hyperbolic flows are entire can be extended to a large new class of multiplicative evolution operators. We construct such operators both for the Gutzwiller semi-classical quantum mechanics and for classical thermodynamic formalism, and introduce a new functional determinant which is expected to be e

N. J. BALMFORTH, P. CVITANOVIC, G. R. IERLEY, E. A. SPIEGEL

We have introduced a new transfer operator for chaotic flows whose leading eigenvalue yields the dynamo rate of the fast kinematic dynamo and applied cycle expansion of the Fredholm determinant of the new operator to evaluation of its spectrum. The theory hs been tested on a normal form model of the vector advecting dynamical flow. If the model is a simple m

M. S. Turner

A procedure is developed for the recovery of the inflationary potential over the interval that affects astrophysical scales ($\approx 1\Mpc - 10^4\Mpc$). The amplitudes of the scalar and tensor metric perturbations and their power-spectrum indices, which can in principle be inferred from large-angle CBR anisotropy experiments and other cosmological data, det

M. Dine, R. G. Leigh, D. A. MacIntire

The original version of this paper contains an error; when this is corrected the basic conclusion changes. A revised manuscript will be submitted shortly.

A. Ceresole, R. D'Auria, T. Regge

We present an efficient method for computing the duality group $Γ$ of the moduli space \cM for strings compactified on a Calabi-Yau manifold described by a two-moduli deformation of the quintic polynomial immersed in $\CP(4)$, $\cW={1\over5}(\iy_1^5+\cdots+\iy_5^5)-a\,\iy_4^3 \iy_5^2 -b\, \iy_4^2 \iy_5^3$. We show that $Γ$ is given by a $3$--dimensional repr

A. Yu. Boldin

The integrability in quadratures of normality equation for spatially homogeneous dynamical systems in two-dimensional space is shown. The classical symmetries of this equation are calculated and the corresponding self-similar solutions are found.

Marvin Rosenblum

This paper studies a suitably normalized set of generalized Hermite polynomials and sets down a relevant Mehler formula, Rodrigues formula, and generalized translation operator. Weighted generalized Hermite polynomials are the eigenfunctions of a generalized Fourier transform which satisfies an F. and M. Riesz theorem on the absolute continuity of analytic m

Andrzej Sitarz

We introduce the analogue of the metric tensor in case of $q$-deformed differential calculus. We analyse the consequences of the existence of such metric, showing that this enforces severe restrictions on the parameters of the theory. We discuss in detail the examples of the Manin plane and the $q$-deformation of $SU(2)$. Finally we touch the topic of relati

B. M. Zupnik

We consider two different types of deformations for the linear group $ GL(n)$ which correspond to using of a general diagonal R-matrix. Relations between braided and quantum deformed algebras and their coactions on a quantum plane are discussed. We show that tensor-grading-preserving differential calculi can be constructed on braided groups , quantum groups

Jacob D. Bekenstein

We rederive the universal bound on entropy with the help of black holes while allowing for Unruh--Wald buoyancy. We consider a box full of entropy lowered towards and then dropped into a Reissner--Nordström black hole in equilibrium with thermal radiation. We avoid the approximation that the buoyant pressure varies slowly across the box, and compute the buoy

S. A. Gurvitz, H. J. Lipkin, Ya. S. Prager

A new method based on modified optical Bloch equations is proposed for studying resonant tunneling in semiconductor heterostructures. The method manifestly takes account of electrons' statistics, which enables to investigate the influence of the Pauli principle on resonant tunneling in presence of inelastic scattering. Being applied to evaluation of the

Giovanni Modanese

A Wilson loop is defined, in 4-D pure Einstein gravity, as the trace of the holonomy of the Christoffel connection or of the spin connection, and its invariance under the symmetry transformations of the action is showed (diffeomorphisms and local Lorentz transformations). We then compute the loop perturbatively, both on a flat background and in the presence

H. Aratyn, L. A. Ferreira, J. F. Gomes, A. H. Zimerman

The discrete models of the Toda and Volterra chains are being constructed out of the continuum two-boson KP hierarchies. The main tool is the discrete symmetry preserving the Hamiltonian structure of the continuum models. The two-boson currents of KP hierarchy are being associated with sites of the corresponding chain by successive actions of discrete symmet

Masahiro MAENO

We investigate the light-cone quantization of $ϕ^3$ theory in 1+1 dimensions with a regularization of discretized light-cone momentum $k^+$. Solving a second-class constraint associated with the $k^+=0$ mode, we show that the $k^+=0$ mode propagates along the internal lines of Feynman diagrams in any order of perturbation, hence our theory recovers the Loren

P. Colangelo, F. De Fazio, G. Nardulli

We evaluate the radiative and hadronic decay rates of the $D^*$ mesons using the Heavy Quark Effective Theory and the Vector Meson Dominance hypothesis. We also estimate the width of the $B^*$ electromagnetic transitions and the radiative decays of positive parity $J^P=0^+, 1^+$ charmed mesons.

S. Sil, S. N. Karmakar, R. K. Moitra, Arunava Chakrabarti

The question of the conditions under which 1D systems support extended electronic eigenstates is addressed in a very general context. Using real space renormalisation group arguments we discuss the precise criteria for determining the entire spertrum of extended eigenstates and the corresponding eigenfunctions in disordered as well as quasiperiodic systems.

Jyotsna Gokhale

We look at the decomposition of the compactified jacobian of a singular curve into components and discuss some examples.

Jyotsna Gokhale

In this work we explore the boundary of the jacobian of a singular curve in the compactified picard group. We formulate a functor that helps to determine this boundary and show that this functor is representable. We try to dertermine the points on the boundary.

M. Kreuzer, H. Skarke

We complete the classification of (2,2) string vacua that can be constructed by diagonal twists of tensor products of minimal models with ADE invariants. Using the \LG\ framework, we compute all spectra from inequivalent models of this type. The completeness of our results is only possible by systematically avoiding the huge redundancies coming from permutat

Maximo Banados, Claudio Teitelboim, Jorge Zanelli

Static, spherically symmetric solutions of the field equations for a particular dimensional continuation of general relativity with negative cosmological constant are studied. The action is, in odd dimensions, the Chern-Simons form for the anti-de Sitter group and, in even dimensions, the Euler density constructed with the Lorentz part of the anti-de Sitter

Tomoyuki Maruyama, Wolfgang Cassing, Ulrich Mosel, Stefan Teis

We introduce momentum-dependent scalar and vector fields into the Lorentz covariant relativistic BUU- (RBUU-) approach employing a polynomial ansatz for the relativistic nucleon-nucleon interaction. The momentum-dependent parametrizations are shown to be valid up to about 1 GeV/u for the empirical proton-nucleus optical potential. We perform numerical simula

Makoto Umeki

The probability distribution functions of the circulation of velocity in three-dimensional decaying isotropic turbulence are examined by the database of the numerical simulation based on the pseudospectral method. It is shown that the standard deviation increases nearly as $A^{2/3}$ where $A$ is the area of the loop. The PDFs change from exponential to gauss

Kai-Ming Lee

We consider the topological interactions of vortices on general surfaces. If the genus of the surface is greater than zero, the handles can carry magnetic flux. The classical state of the vortices and the handles can be described by a mapping from the fundamental group to the unbroken gauge group. The allowed configurations must satisfy a relation induced by

R. L. Jaffe, Xiangdong Ji

We define twist-two and twist-three quark fragmentation functions in Quantum Chromodynamics (QCD) and study their physical implications. Using this formalism we show how the nucleon's transversity distribution can be measured in single pion inclusive electroproduction.

R. Foot, H. Lew

Theoretically, the electric charge of the tau neutrino may be non-zero. The experimental bound on the electric charge of the tau neutrino is many orders of magnitude weaker than that for any other known neutrino. If the tau neutrino does have a small electric charge, and its mass is greater than 1 MeV, then it can annihilate sufficiently in the early Univers

N. I. Ussyukina, A. I. Davydychev

Evaluation of three- and four-point diagrams with massless internal particles and arbitrary external momenta is considered. Exact results for some two-loop diagrams (planar and non-planar three-point contributions and the "double box" diagram) are obtained in terms of polylogarithms.

V. P. Nair

The generating functional for hard thermal loops in QCD is rewritten in terms of a gauged WZNW action by introducing an auxiliary field. This shows in a simple way that the contribution of hard thermal loops to the energy of the quark-gluon plasma is positive.

David Wands

I discuss the relation between arbitrarily high-order theories of gravity and scalar-tensor gravity at the level of the field equations and the action. I show that $(2n+4)$-order gravity is dynamically equivalent to Brans-Dicke gravity with an interaction potential for the Brans-Dicke field and $n$ further scalar fields. This scalar-tensor action is then con

Marc B. Reider, James D. Sterling

Two discretizations of a 9-velocity Boltzmann equation with a BGK collision operator are studied. A Chapman-Enskog expansion of the PDE system predicts that the macroscopic behavior corresponds to the incompressible Navier-Stokes equations with additional terms of order Mach number squared. We introduce a fourth-order scheme and compare results with those of

Andrea Ferrara, Yuri Shchekinov

We investigate the evolution of interfaces among phases of the interstellar medium with different temperature. It is found that, for some initial conditions, the dynamical effects related to conductive fronts are very important even if radiation losses, which tend to decelerate the front propagation, are taken into account. We have also explored the conseque

Edmund Bertschinger, Bhuvnesh Jain

We solve the nonlinear evolution of pressureless, irrotational density fluctuations in a perturbed Robertson-Walker spacetime using a new Lagrangian method based on the velocity gradient and gravity gradient tensors. Borrowing results from general relativity, we obtain a set of Newtonian ordinary differential equations for these quantities following a given

G. Belanger, D. London, H. Nadeau

We consider single production of leptoquarks (LQ's) at $e^+e^-$ and $γγ$ colliders, for two values of the centre-of-mass energy, $\sqrt{s}=500$ GeV and 1 TeV. We find that LQ's which couple within the first generation are observable for LQ masses almost up to the kinematic limit, both at $e^+e^-$ and $γγ$ colliders, for the LQ coupling strength equal

David A. Egolf, Henry S. Greenside

We consider spatiotemporal chaotic systems for which spatial correlation functions decay substantially over a length scale xi (the spatial correlation length) that is small compared to the system size L. Numerical simulations suggest that such systems generally will be extensive, with the fractal dimension D growing in proportion to the system volume for suf

Jonathan Bagger, Erich Poppitz

Nonrenormalizable couplings in supergravity-coupled supersymmetric theories can give rise to power-law divergences that destabilize the weak-scale hierarchy. For the case of the standard-model gauge group, the problem can arise in theories with \321 gauge-singlet chiral superfields. The minimal supersymmetric standard model is free from such destabilizing di

R. Smolańczuk, J. Dobaczewski

We calculate positions of one- and two-particle, proton and neutron drip lines within the Hartree-Fock-Bogoliubov theory using Skyrme interaction. We also determine an approximate $r$-process path defined as a line where the neutron binding energy is equal to 2~MeV. A weakening of the nuclear shell structure at drip lines is found and interpreted as resultin

M. J. Musolf, T. W. Donnelly, J. Dubach, S. J. Pollock

The present and future prospects of intermediate-energy semileptonic neutral current studies are reviewed. Possibilities for using neutrino and parity-violating electron scattering from nucleons and nuclei to study hadron structure and nuclear dynamics are emphasized, with particular attention paid to probes of the nucleon's strangeness content. Connecti

J. G. Russo

A common belief is that further quantum corrections near the singularity of a large black hole should not substantially modify the semiclassical picture of black hole evaporation; in particular, the outgoing spectrum of radiation should be very close to the thermal spectrum predicted by Hawking. In this paper we explore a possible counterexample: in the cont

R. Loll, J. M. Mourão, J. N. Tavares

For the case of a first-class constrained system with an equivariant momentum map, we study the conditions under which the double process of reducing to the constraint surface and dividing out by the group of gauge transformations $G$ is equivalent to the single process of dividing out the initial phase space by the complexification $G_C$ of $G$. For the par

D. Nemeschansky, N. P. Warner

We obtain off-critical (elliptic) Boltzmann weights for lattice models whose continuum limits correspond to massive, $N=2$ supersymmetric, quantum integrable field theories. We also compute the free energies of these models and show that they are analytic in the region of parameter space where we believe that the supersymmetry is unbroken. While the supersym

S. P. de Alwis

In this paper an attempt is made to understand the passage from the exact quantum treatment of the CGHS theory to the semi-classical physics discussed by many authors. We find first that to the order of accuracy to which Hawking effects are calculated in the theory, it is inconsistent to ignore correlations in the dilaton gravity sector. Next the standard Di

Hiromichi Nakazato, Saverio Pascazio

By making use of Schwinger's oscillator model of angular momentum, we put forward an interesting connection among three solvable Hamiltonians, widely used for discussions on the quantum measurement problem. This connection implies that a particular macroscopic limit has to be taken for these models to be physically sensible.

A. L. Larsen

We consider the propagation of perturbations along an infinitely long stationary open string in the background of a Schwarzschild black hole. The equations of motion for the perturbations in the 2 transverse physical directions are solved to second order in a weak field expansion. We then set up a scattering formalism where an ingoing wave is partly transmit

Tamio Ikehashi

Using the hamiltonian formalism, we investigate the smooth bosonization method in which bosonization and fermionization are carried out through a specific gauge-fixing of an enlarged gauge invariant theory. The generator of the local gauge symmetry, which cannot be derived from the lagrangian of the enlarged theory, is obtained by making a canonical transfor

Daren Austin, E. J. Copeland, T. W. B. Kibble

We extend and develop our previous work on the evolution of a network of cosmic strings. The new treatment is based on an analysis of the probability distribution of the end-to-end distance of a randomly chosen segment of left-moving string of given length. The description involves three distinct length scales: $ξ$, related to the overall string density, $\b

A. I. Davydychev

By using the example of photon-photon scattering box diagrams, different representations for loop integrals are discussed. A connection between hypergeometric representation and dilogarithms is derived. An explicit analytic continuation formula to large values of Mandelstam variables is constructed.

Ulrich Ellwanger, Michel Rausch de Traubenberg, Carlos A. Savoy

We scan the complete parameter space of the supersymmetric standard model extended by a gauge singlet, which is compatible with the following constraints: universal soft supersymmetry breaking terms at the GUT scale, finite running Yukawa couplings up to the GUT scale and present experimental bounds on all sparticles, Higgs scalar and top quark. The full rad

Akizo Kobayashi, Shoji Sawada

A quantization of a breathing motion of a rotating chiral soliton on $S^3$ is performed in terms of a family of trial functions for a profile function of the hegdehog ansatz. We determine eigenenergies of the quantized $S^3$ skyrmion by solving the Schrödinger equation of the breathing mode for several lower spin and isospin states varying the Skyrme term co

M. Carena, L. Clavelli, D. Matalliotakis, H. P. Nilles

We analyze the implications of the light gluino scenario for the unification of gauge and Yukawa couplings within the minimal supersymmetric standard model. Within this scheme all fermionic supersymmetric particles are naturally light, while the scalar partners of quarks and leptons, together with the heavy Higgs doublet may be heavy. This implies both a bou

P. E. Haagensen

It is possible to find different sets of local coordinates in the field space of Yang-Mills theories which implement Gauss' law manifestly for physical states. The singular points of the transformations to these gauge-invariant coordinates induce energy barriers in the Hamiltonian much like angular momentum in quantum mechanics, and these formulations su

Andrzej J. Buras

We point out that the lower bound on $m_t$ from the CP violation parameter $ε_K$ has increased considerably. Using Wolfenstein parametrization of the CKM matrix we derive an analytic expression for this bound as a function of $\mid V_{cb}\mid, \mid V_{ub}/V_{cb}\mid$ and the non-perturbative parameter $B_K$. For $B_K\leq 0.80,\mid V_{cb} \mid\leq 0.040$ and

Poul H. Damgaard, Urs M. Heller

We describe various aspects of statistical mechanics defined in the complex temperature or coupling-constant plane. Using exactly solvable models, we analyse such aspects as renormalization group flows in the complex plane, the distribution of partition function zeros, and the question of new coupling-constant symmetries of complex-plane spin models. The dou

B. K. Berger, V. Moncrief

Although cosmological solutions to Einstein's equations are known to be generically singular, little is known about the nature of singularities in typical spacetimes. It is shown here how the operator splitting used in a particular symplectic numerical integration scheme fits naturally into the Einstein equations for a large class of cosmological models

Y. Bi, J. Gegenberg

We examine the relationship between covariant and canonical (Ashtekar/Rovelli/Smolin) loop variables in the context of BF type topological field theories in 2+1 and 3+1 dimensions, with respective gauge groups SO(2,1) and SO(3,1). The latter model can be considered as the simplest topological gravity theory in 3+1 dimensions. We carry out the canonical quant

J. Madore, J. Mourad

The commutative algebra of functions on a manifold is extended to a noncommutative algebra by considering its tensor product with the algebra of nxn complex matrices. Noncommutative geometry is used to formulate an extension of the Einstein-Hilbert action. The result is shown to be equivalent to the usual Kaluza-Klein theory with the manifold SUn as an inter

D. Lai, F. A. Rasio, S. L. Shapiro

We present a new analytic study of the equilibrium and stability properties of close binary systems containing polytropic components. Our method is based on the use of ellipsoidal trial functions in an energy variational principle. We consider both synchronized and nonsynchronized systems, constructing the compressible generalizations of the classical Darwin

A. A. Coley, T. Trappenberg

We review recent lattice QCD results for the surface tension at the finite temperature quark-hadron phase transition and discuss their implications on the possible scale of inhomogeneities. In the quenched approximation the average distance between nucleating centers is smaller than the diffusion length of a protron, so that inhomogeneities are washed out by

Tomoyuki Hanawa, Satoshi Yamamoto, Yasuhiro Hirahara

We discuss the fragmentation of a filamentary cloud on the basis of a 1-dimensional hydrodynamical simulation of a self-gravitating gas cloud. The simulation shows that dense cores are produced with a semi-regular interval in space and time from one edge to the other. At the initial stage the gas near one of the edges is attracted inwards by gravity and the

C. P. Burgess, J. M. Cline

Motivated by the excess events that have recently been found near the endpoints of the double beta decay spectra of several elements, we re-examine models in which double beta decay can proceed through the neutrinoless emission of massless Nambu-Goldstone bosons (majorons). Noting that models proposed to date for this process must fine-tune either a scalar m

W. G. Unruh, Peter Newbury

The reduction of the dreibein formalism of 2+1 General Relativity to the holonomies is explicitly performed. We also show explicitly how to relate these holonomies to a geometry classically, and how to generate these holonomies from any initial data for 2+1 gravity obeying the constraints.

B. Sriram Shastry, Elihu Abrahams

We present an analysis of the Korringa ratio in a dirty metal, emphasizing the case where a Stoner enhancement of the uniform susceptibilty is present. We find that the relaxation rates are significantly enhanced by disorder, and that the inverse problem of determining the bare density of states from a study of the change of the Knight shift and relaxation r

Alexander Sokol, Rodney L. Glenister, Rajiv R. P. Singh

Using high temperature expansions for the equal time correlator $S(q)$ and static susceptibility $χ(q)$ for the t-J model, we present evidence for quantum critical (QC), $z\!=\!1$, behavior at intermediate temperatures in a broad range of $t/J$ ratio, doping, and temperatures. We find that the dynamical susceptibility is very close to the universal scaling f

Stephen Lau

Recently Brown and York have devised a new method for defining quasilocal energy in general relativity. Their method yields expressions for the quasilocal energy and momentum surface densities associated with the two-boundary of a spacelike slice of a spatially bounded spacetime. These expressions are essentially Arnowitt-Deser-Misner variables, but with can

Shun'ya Mizoguchi, Hisashi Yamamoto

Preliminary investigations are made for the stability of the $1/N$ expansion in three-dimensional gravity coupled to various matter fields, which are power-counting renormalizable. For unitary matters, a tachyonic pole appears in the spin-2 part of the leading graviton propagator, which implies the unstable flat space-time, unless the higher-derivative terms

Avinash Khare, Fred Cooper

We study the generalized Korteweg-DeVries equations derivable from the Lagrangian: $ L(l,p) = \int \left( \frac{1}{2} φ_{x} φ_{t} - { {(φ_{x})^{l}} \over {l(l-1)}} + α(φ_{x})^{p} (φ_{xx})^{2} \right) dx, $ where the usual fields $u(x,t)$ of the generalized KdV equation are defined by $u(x,t) = φ_{x}(x,t)$. For $p$ an arbitrary continuous parameter $0< p \leq

Abraham Klein, Niels R. Walet

We study the algebra Sp(n,R) of the symplectic model, in particular for the cases n=1,2,3, in a new way. Starting from the Poisson-bracket realization we derive a set of partial differential equations for the generators as functions of classical canonical variables. We obtain a solution to these equations that represents the classical limit of a boson mappin

J. Mourad

The relativistic semi-classical approximation for a free massive particle is studied using the Wigner-Weyl formalism. A non-covariant Wigner function is proposed using the Newton-Wigner position operator. The perturbative solution for the time evolution is found. Causality is found to be perturbatively respected.

J. Mourad

We show that there is only one operator having some minimal properties enabling it to be a one photon position operator. These proerties are stated, and the solution is shown to be the photon position operator proposed by Pryce. This operator has non-commuting components. Nevertheless, it is shown that one can find states localized with an arbitrary precisio

M. Temple-Raston

We approximate analytically the semi-classical differential cross-section for low-energy solitonic BPS SU(2) magnetic monopoles using the geodesic approximation. The semi-classical scattering amplitude, f(θ), can be expressed as a conditionally convergent infinite series which is made absolutely convergent by analytic continuation of the generalised zeta fun