April 1993 arXiv papers — page 3

P. D. D'Eath

By solving the supersymmetry constraints for physical wave-functions, it is shown that the only two allowed bosonic states in $ N = 1 $ supergravity are of the form const.~exp~$(\pm I / \hbar) $, where $ I $ is an action functional of the three-metric. States containing a finite number of fermions are forbidden. In the case that the spatial topology is $ S^3

N. S. Han, A. Honecker

Using perturbative methods we derive new results for the spectrum and correlation functions of the general Z_3-chiral Potts quantum chain in the massive low-temperature phase. Explicit calculations of the ground state energy and the first excitations in the zero momentum sector give excellent approximations and confirm the general statement that the spectrum

J. Lopez, D. Nanopoulos, G. Park

We present a calculation of the branching ratio $\brbsg$ in two well motivated supersymmetric models: the minimal $SU(5)$ and the no-scale flipped $SU(5)$ supergravity models. We find that the improved CLEO upper bound ($\brbsg<5.4\times10^{-4}$ at 95\% CL) does not yet constrain the minimal $SU(5)$ supergravity model, where $\brbsg_{minimal}=(2.3-3.6)\times

M. B. Gay Ducati, F. Halzen, A. A. Natale

We recently proposed a QCD-Pomeron described by the exchange of two non-perturbative gluons characterized by a dynamically generated gluon mass. It is here shown that data on elastic scattering, exclusive $ρ$ production in deep inelastic scattering and the $J/Ψ$-nucleon total cross-section can be successfully described in terms of a single gluon mass $m_g\si

V. Bernard, N. Kaiser, Ulf-G. Meißner

We calculate the chiral corrections to Weinberg&#39;s prediction for the S--wave $πN$ scattering lengths up--to--and--including order ${\cal O}(M_π^3)$ making use of heavy baryon chiral perturbation theory. For the isospin--odd scattering length $a^-$ these corrections are small and bring the prediction closer to the empirical value. In the case of the isosp

Ugo Aglietti

The effective theory describing infinite mass particles with a given velocity, has a great interest in heavy flavor physics. It has the unpleasant characteristic that the energy spectrum is unbounded from below; this fact is the source of the problems in the formulation of the euclidean theory. In this paper we present an analysis of the euclidean effective

Kari Enqvist, Jukka Sirkka

We compute the thermally averaged $\qq$--annihilation rate into two and three gluons in the early universe. We show that at very high temperatures $\qq\to ggg$ represents only a 3\%\ correction to $\qq\to gg$. Comparing the annihilation rate to the Hubble rate, corrected for particle interactions in the Standard Model gas, we find that quarks and gluons are

Y. Liang, K. F. Liu, B. A. Li, S. J. Dong

Matrix elements of the form $ <0| Tr \; g^{2}GG |G> $ are calculated using the lattice QCD Monte Carlo method. Here, $|G>$ is a glueball state with quantum numbers $ 0^{++}$, $ 2^{++}$, $ 0^{-+}$ and $G$ is the gluon field strength operator. The matrix elements are obtained from the hybrid correlation functions of the fuzzy and plaquette operators performed

Juan Pablo Paz, Wojciech Hubert Zurek

We prove that for an open system, in the Markovian regime, it is always possible to construct an infinite number of non trivial sets of histories that exactly satisfy the probability sum rules. In spite of being perfectly consistent, these sets manifest a very non--classical behavior: they are quite unstable under the addition of an extra instant to the list

F. M. Paiva, C. Romero

We investigate the limit of Brans-Dicke spacetimes as the scalar field coupling constant omega tends to infinity applying a coordinate-free technique. We obtain the limits of some known exact solutions. It is shown that these limits may not correspond to similar solutions in the general relativity theory.

Gerhard Rein

The Vlasov-Einstein system describes the evolution of an ensemble of particles (such as stars in a galaxy, galaxies in a galaxy cluster etc.) interacting only by the gravitational field which they create collectively and which obeys Einstein&#39;s field equations. The matter distribution is described by the Vlasov or Liouville equation for a collisionless ga

H. Rosu, E. Canessa

Davydov&#39;s model of solitons in alpha-helix protein chains is shown to display features of self-organized criticality (SOC), i.e., power law behaviour of correlations in space and 1/f-noise, as a consequence of considering random peptide group displacements from their (periodic) equilibrium positions along a chain. This may shed light on a basic mechanism

Bill Sutherland, Rudolf A. R&#34;omer

In this paper, we present the exact solution to a one-dimensional, two-component, quantum many-body system in which like particles interact with a pair potential $s(s+1)/{\rm sinh}^{2}(r)$, while unlike particles interact with a pair potential $-s(s+1)/{\rm cosh}^{2}(r)$. We first give a proof of integrability, then derive the coupled equations determining t

R. Schaeffer, S. Maurogordato, A. Cappi, F. Bernardeau

Velocity dispersion $σ$, radius $R$ and luminosity $L$ of elliptical galaxies are known to be related, leaving only two degrees of freedom and defining the so-called ``fundamental plane&#34;. In this {\em Letter} we present observational evidence that rich galaxy clusters exhibit a similar behaviour. Assuming a relation $L \propto R^ασ^{2 β}$, the best-fit v

B. S. Balakrishna

A criterion to be satisfied by a string theory of QCD is formulated in the ultraviolet regime. It arises from the trace anomaly of the QCD stress tensor computed using instantons. It is sensitive to asymptotic freedom. It appears to be related to the trace anomaly of the QCD string. Our current understanding of noncritical strings in physical dimensions is l

K. Isler, M. B. Paranjape

We study the equations for the quasi-momenta which characterize the wave-functions in the Bethe ansatz for the XXX-Heisenberg model. We show in a simple analytical fashion, that the usual ``string hypothesis&#34; incorrectly predicts the number of real solutions and the number of complex solutions for $N>21$ in the sector with two spins flipped, confirming t

M. Stoilov, R. Zaikov

We consider a simple model of a scalar field with $U(1)$ current algebra gauge symmetry coupled to $2D$-gravity in order to clarify the origin of Stuckelberg symmetry in the $w_{\infty}$-gravity theory. An analogous symmetry takes place in our model too. The possible central extension of the complete symmetry algebra and the corresponding critical dimension

D. Comelli, M. Pietroni, A. Riotto

We investigate the effects of the spontaneous CP violation at finite temperature in the Minimal Supersymmetric Standard Model on the baryogenesis at the weak scale. After a brief discussion of the case in which the electroweak phase transition is of the second order, we study in details the baryogenesis scenario when the transition proceeds via bubble nuclea

C. J. Efthimiou

Using a hybrid approach, based on the recursion relations for shape invariant potentials developed by Das and Huang and a time-dependent tranformation of variables, we derive the propagator for a radial oscillator. Although this is not a new result, we explicitly show that time-dependent tranformations are very beneficial even within the context of time-inde

M. Asorey, S. Carlip, F. Falceto

In an abelian topologically massive gauge theory, any eigenstate of the Hamiltonian can be decomposed into a factor describing massive propagating gauge bosons and a Chern-Simons wave function describing a set of nonpropagating ``topological&#39;&#39; excitations. The energy depends only on the propagating modes, and energy eigenstates thus occur with a dege

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

In this talk we report some results about the construction of soliton solutions for the Affine and Conformal Affine Toda models using the Hirota&#39;s method. We obtain new classes of solitons connected to the degeneracies of the Cartan matrix eigenvalues as well as to some particular features of the recursive scheme developed here. We obtain an universal ma

T. Hakobyan, A. G. Sedrakyan

We obtain the formula for intertwining operator(R-matrix) of quantum universal enveloping superalgebra U_qOSP(1,2) for U_qOSP(1,2)-Verma modules. By its restriction we obtain the R-matrix for two semiperiodic(semicyclic), two spin-j and spin-j and semiperiodic representations

Raiko P. Zaikov

It is shown that the generalized (with nonpolynomial Lagrangian) Chern-Simons membranes and in general $p$-branes moving in $D$-dimensional target space admit an infinite set of secondary constraints. With respect to the Poisson bracket these constraints satisfy closed algebra containing $p$-dimensional classical $W$ algebra as a subalgebra. In the case when

Stjepan Meljanac, Marijan Milekovic

We show that the Clebsch - Gordan coefficients for the $SU(2)_{p,q}$ - algebra depend on a single parameter Q = $\sqrt{pq}$ ,contrary to the explicit calculation of Smirnov and Wehrhahn [J.Phys.A 25 (1992),5563].

Stjepan Meljanac, Marijan Milekovic

A covariant - tensor method for $SU(2)_{q}$ is described. This tensor method is used to calculate q - deformed Clebsch - Gordan coefficients. The connection with covariant oscillators and irreducible tensor operators is established. This approach can be extended to other quantum groups.

E. Elizalde, S. Leseduarte, S. D. Odintsov

Exact expressions for the partition functions of the rigid string and membrane at any temperature are obtained in terms of hypergeometric functions. By using zeta function regularization methods, the results are analytically continued and written as asymptotic sums of Riemann-Hurwitz zeta functions, which provide very good numerical approximations with just

Iwo Bialynicki-Birula

A discretized time evolution of the wave function for a Dirac particle on a cubic lattice is represented by a very simple quantum cellular automaton. In each evolution step the updated value of the wave function at a given site depends only on the values at the nearest sites, the evolution is unitary and preserves chiral symmetry. Moreover, it is shown that

Ivan K. Kostov

We review the basics of the dynamics of closed strings moving along the discretized line \Z. The string excitations are described by a field ϕ_x(τ) where x is the position of the string in the embedding space and τis a semi-infinite ``euclidean time&#39;&#39; parameter related to the longitudinal mode of the string. Interactions due to splitting and joining

Da-Shin Lee, Daniel Boyanovsky

We study the non-equilibrium dynamics of a symmetry restoring phase transition in a scalar field theory, the ``system&#39;&#39;, linearly coupled to another scalar field taken as a ``heat bath&#39;&#39;. The ``system&#39;&#39; is initially in an ordered low temperature phase, and the heat bath is at a temperature close to the critical temperature for the sys

Stephen Parke

There is renewed interest in performing a long baseline neutrino oscillation experiment using accelerator neutrinos because of a discrepancy between the measured and the predicted values of the ratio of electron to muon neutrinos produced in the upper atmosphere by cosmic rays.The approximate range in oscillation parameter space indicated by the Kamiokande a

Sean Fleming

The decay $Z^{0}\rightarrow Q+ \ell^{+}\ell^{-}$, where $Q$ is a $J^{PC}=1^{--}$ quarkonium state, has a very clean final state, which should make it easy to detect. The branching ratio of this mode is greater than $10^{-6}$ for $ρ$, $ϕ$, and $ψ$, indicating that these processes may be detectable at LEP.

A. Blumhofer, M. Lindner

Custodial $SU(2)$ breaking due to dynamical fermion masses is studied in a rather general context and it is shown how some well known limiting cases are correctly described. The type of ``gap equation&#39;&#39; which can systematically lead to extra negative contributions to the so--called $ρ$--parameter is emphasized. Furthermore general model independent f

Harry J. Lipkin

Recent data on the $D^*$ masses confirm the QCD prediction based on the \REF{\ICHJL}{Isaac Cohen and Harry J. Lipkin, \plb{84}{323}{1979}} very general assumption $\({\ICHJL}\)$ that the spin-dependence of the quark couplings to photons and gluons have the same structure and differ only in the value of the coupling constants, This prediction with no free par

Don N. Page

With CPT-invariant initial conditions that commute with CPT-invariant final conditions, the respective probabilities (when defined) of a set of histories and its CPT reverse are equal, giving a CPT-symmetric universe. This leads me to question whether the asymmetry of the Gell-Mann--Hartle decoherence functional for ordinary quantum mechanics should be inter

David Brown

Action functionals describing relativistic perfect fluids are presented. Two of these actions apply to fluids whose equations of state are specified by giving the fluid energy density as a function of particle number density and entropy per particle. Other actions apply to fluids whose equations of state are specified in terms of other choices of dependent a

Martin Schoen

Arguments are given that time must be defined in an operative manner,i.e., by constructing devices which can serve as clocks.The investigation of such devices leads to the conclusion that there is a principal uncertainity of time if one considers periods which are not large compared with the Planck time. Thus,according to the old (classical) concept,time can

Martin Holthaus, Michael E. Flatte&#39;

We show how the classical-quantum correspondence permits long-lived subharmonic motion in a quantum system driven by a periodic force. Exponentially small deviations from exact subharmonicity are due to coherent tunneling between quantized vortex tubes which surround classical elliptic periodic orbits.

Paul Fendley

We find the exact quasiparticle spectrum for the continuum Kondo problem of $k$ species of electrons coupled to an impurity of spin $S$. In this description, the impurity becomes an immobile quasiparticle sitting on the boundary. The particles are ``kinks&#39;&#39;, which can be thought of as field configurations interpolating between adjacent wells of a pot

Jysoo Lee, Stefan Schwarzer, Antonio Coniglio, H. Eugene Stanely

The growth of a diffusion limited aggregation (DLA) cluster with mass $M$ and radius of gyration $R$ is described by a set of growth probabilities $\{ p_i\}$, where $p_i$ is the probability that the perimeter site $i$ will be the next to grow. We introduce the joint distribution $N(α, x, M)$, where $N(α,x,M)dαdx$ is the number of perimeter sites with $α$-val

Enrico Nardi

Conventional superstring derived E$_6$ models can accommodate small neutrino masses if a discrete symmetry is imposed which forbids tree level Dirac neutrino masses but allows for radiative mass generation. Since the only possible symmetries of this kind are known to be generation dependent, we explore the possibility that the three sets of light states in e

Murray Gell-Mann, James B. Hartle

We investigate the origin of the arrow of time in quantum mechanics in the context of quantum cosmology. The ``Copenhagen&#39;&#39; quantum mechanics of measured subsystems incorporates a fundamental arrow of time. Extending discussions of Aharonov, Bergmann and Lebovitz, Griffiths, and others we investigate a generalized quantum mechanics for cosmology that

Arlen Anderson, Jonathan J. Halliwell

We study an information-theoretic measure of uncertainty for quantum systems. It is the Shannon information $I$ of the phase space probability distribution $\la z | ρ| z \ra $, where $|z \ra $ are coherent states, and $ρ$ is the density matrix. The uncertainty principle is expressed in this measure as $I \ge 1$. For a harmonic oscillator in a thermal state,

R. A. Sharipov

The problem of metrizability for the dynamical systems accepting the normal shift is formulated and solved. The explicit formula for the force field of metrizable Newtonian dynamical system $\ddot\bold r=\bold F(\bold r,\dot\bold r)$ is found.

Andrew R Liddle, David H Lyth

Recent large scale structure observations, including COBE, have prompted many authors to discuss modifications of the standard Cold Dark Matter model. Two of these, a tilted spectrum and a gravitational wave contribution to COBE, are at some level demanded by theory under the usual assumption that inflation generates the primeval perturbations. The third, wh

Avinash Dhar, Gautam Mandal, Spenta R. Wadia

We further study the nonperturbative formulation of two-dimensional black holes. We find a nonlinear differential equation satisfied by the tachyon in the black hole background. We show that singularities in the tachyon field configurations are always associated with divergent semiclassical expansions and are absent in the exact theory. We also discuss how t

John E. Pearson

Numerical simulations of a simple reaction--diffusion model reveal a surprising variety of irregular spatio--temporal patterns. These patterns arise in response to finite--amplitude perturbations. Some of them resemble the steady irregular patterns discussed by Lee et al. Others consist of spots which grow until they reach a critical size at which time they

N. K. Devine, S. J. Wallace

The quasipotential formalism for elastic scattering from relativistic bound states is formulated based on the instant constraint in the Breit frame. The quasipotential electromagnetic current is derived from Mandelstam&#39;s five-point kernel and obeys a two-body Ward identity. Breit-frame wave functions are obtained directly by solving integral equations wi

Feliks Przytycki, Anna Zdunik

We prove that if A is the basin of immediate attraction to a periodic attracting or parabolic point for a rational map f on the Riemann sphere, then periodic points in the boundary of A are dense in this boundary. To prove this in the non simply- connected or parabolic situations we prove a more abstract, geometric coding trees version.

A. P. Balachandran, P. Teotonio-Sobrinho

Let $B$ and $F=\frac 12F_{μν}dx^μ\wedge dx^ν$ be two forms, $F_{μν}$ being the field strength of an abelian connection $A$. The topological $BF$ system is given by the integral of $B\wedge F$. With &#34;kinetic energy&#39;&#39; terms added for $B$ and $A$, it generates a mass for $A$ thereby suggesting an alternative to the Higgs mechanism, and also gives th

J. S. Bagla, T. Padmanabhan

During the evolution of density inhomogeneties in an $\Omega=1$, matter dominated universe, the typical density contrast changes from $\delta\simeq 10^{-4}$ to $\delta\simeq 10^2$. However, during the same time, the typical value of the gravitational potential generated by the perturbations changes only by a factor of order unity. This significant fact can b

B. Holdom, Randy Lewis, Roberto R. Mendel

A simple model for the hadronic contribution to the photon vacuum polarization function $Π_{had}(q^2)$, for spacelike momenta, is presented. For small momenta, the two loop contribution from the pseudoscalar meson octet is computed from the chiral Lagrangian. The light quark contribution (which at low momentum gives the ${\cal O}(q^6)$ counterterm in the chi

Jin-Ho Cho, Seungjoon Hyun, Jae-Kwan Kim

The spin degrees of freedom for the relativistic particle are described by either Poincaré group variables (classically) or Grassmann variables (pseudo-classically). The relationship between those two descriptions are given. In doing that, appropriate constraints are constructed to put into the lagrangian. Especially a natural relation of Poincaré group vari

D. Bailin, A. Love, W. A. Sabra

A study is made for ${\bf Z}_M\times {\bf Z}_N$ orbifolds of the modification of the form of the twisted sector Yukawa couplings when some of the states involved are excited twisted sectors rather than twisted sector ground states.

Estelle L. Basor, Craig A. Tracy

In the Laguerre ensemble of N x N (positive) hermitian matrices, it is of interest both theoretically and for applications to quantum transport problems to compute the variance of a linear statistic, denoted var_N f, as N->infinity. Furthermore, this statistic often contains an additional parameter alpha for which the limit alpha->infinity is most interestin

Craig A. Tracy, Harold Widom

The level spacing distributions which arise when one rescales the Laguerre or Jacobi ensembles of hermitian matrices is studied. These distributions are expressible in terms of a Fredholm determinant of an integral operator whose kernel is expressible in terms of Bessel functions of order $α$. We derive a system of partial differential equations associated w

Jae-Suk Park

We study a topological Yang-Mills theory with $N=2$ fermionic symmetry. Our formalism is a field theoretical interpretation of the Donaldson polynomial invariants on compact Kähler surfaces. We also study an analogous theory on compact oriented Riemann surfaces and briefly discuss a possible application of the Witten&#39;s non-Abelian localization formula to

Kenji Kajiwara, Yasuhiro Ohta, Junkichi Satsuma

A q-discrete version of the two-dimensional Toda molecule equation is proposed through the direct method. Its solution, Bäcklund transformation and Lax pair are discussed. The reduction to the q-discrete cylindrical Toda molecule equation is also discussed.

Ana Achúcarro, Miguel Ortiz

The three dimensional black hole solutions of Bañados, Teitelboim and Zanelli (BTZ) are dimensionally reduced in various different ways. Solutions are obtained to the Jackiw-Teitelboim theory of two dimensional gravity for spinless BTZ black holes, and to a simple extension with a non-zero dilaton potential for black holes of fixed spin. Similar reductions a

E. Corrigan, P. E. Dorey, R. Sasaki

The S-matrices for non-simply-laced affine Toda field theories are considered in the context of a generalised bootstrap principle. The S-matrices, and in particular their poles, depend on a parameter whose range lies between the Coxeter numbers of dual pairs of the corresponding non-simply-laced algebras. It is proposed that only odd order poles in the physi

Mirjam Cvetic

We study dilatonic domain walls specific to superstring theory. Along with the matter fields and metric the dilaton also changes its value in the wall background. We found supersymmetric (extreme) solutions which in general interpolate between isolated superstring vacua with non-equal value of the matter potential; they correspond to the static, planar domai

William A. Bardeen, Christopher T. Hill

We study a solvable QCD--like toy theory, a generalization of the Nambu--Jona-Lasinio model, which implements chiral symmetries of light quarks and heavy quark symmetry. The chiral symmetric and chiral broken phases can be dynamically tuned. This implies a parity doubled heavy--light meson system, corresponding to a $(0^-,1^-)$ multiplet and a $(0^+,1^+)$ he

T. G. Rizzo

The recent results of the CLEO Collaboration on both inclusive and exclusive radiative $B$ decays are combined with those of the UA2 Collaboration on $Wγ$ production to highly constrain the anomalous trilinear gauge couplings of the $W$. The theoretical analysis of the $b \to sγ$ process employs, next-to-leading order operator coefficient evolution as well a

Santiago Peris, Eduardo de Rafael

It is shown that in the constituent quark model of Georgi-Manohar, the dispersion relation that leads to the Adler-Weisberger sum rule for the axial vector coupling $g_A$ requires a subtraction constant. This fact explains the discrepancy between the results of different recent estimates of the $1/N_c$ corrections to Weinberg&#39;s large $N_c$ result $g_A=1$

I. Balitsky, A. Schäfer

We compare the two most popular approaches to the problem of instanton-antiinstanton interaction at high energies - the valley method and the effective-Lagrangian approach - and use them to calculate the next-to-next-to-leading term in the expansion of ``holy grail&#39;&#39; function determining the cross section with baryon number violation in the Standard

Stamatis Vokos

We examine a recent suggestion by Milburn that slightly massive electron neutrinos, produced left-handed at the core of the sun, suffer geodetic precession adequate to render them right-handed (and therefore sterile) in sufficient numbers to solve the solar neutrino problem. In that light, we perform a complete, general-relativistic calculation of the geodet

Vittorio Del Duca

The Parke-Taylor multigluon amplitudes are examined in the multi-Regge kinematics, which assumes strong rapidity ordering of the produced gluons, and are used to compute the $n$-gluon production cross section and the gluon-gluon total cross section.

R. Nityananda, T. Padmanabhan

The growth of density perturbations in an expanding universe in the non-linear regime is investigated. The underlying equations of motion are cast in a suggestive form, and motivate a conjecture that the scaled pair velocity, $h(a,x)\equiv -[v/(\dot{a}x)]$ depends on the expansion factor $a$ and comoving coordinate $x$ only through the density contrast $σ(a,

F. Ladieu, D. Mailly, M. Sanquer

We have observed reproducible conductance fluctuations at low temperature in a small GaAs:Si wire driven across the Anderson transition by the application of a gate voltage. We analyse quantitatively the log-normal conductance statistics in terms of truncated quantum fluctuations. Quantum fluctuations due to small changes of the electron energy (controlled b

Yshai Avishai, Jean-Louis Pichard, Khandker A. Muttalib

We consider quantum interferences of classically allowed or forbidden electronic trajectories in disordered dielectrics. Without assuming a directed path approximation, we represent a strongly disordered elastic scatterer by its transmission matrix ${\bf t}$. We recall how the eigenvalue distribution of ${\bf t.t}^{\dagger}$ can be obtained from a certain an

François Ladieu, Jean-Philippe Bouchaud

We analyse in detail Mott&#39;s variable range hopping in one dimension, expanding on earlier work by Raikh and Ruzin. We show that the large conductance fluctuations in disordered insulators result from a subtle interplay between purely quantum phenomena and geometrical fluctuations arising from the energies and locations of the impurities. Our results comp

A. Crisanti, M falcioni, A. Vulpiani

We study the long time behaviour of the transient before the collapse on the periodic attractors of a discrete deterministic asymmetric neural networks model. The system has a finite number of possible states so it is not possible to use the term chaos in the usual sense of sensitive dependence on the initial condition. Nevertheless, at varying the asymmetry

A. Crisanti, G. Paladin, M. Serva, A. Vulpiani

We introduce a one dimensional disordered Ising model which at zero temperature is characterized by a non-trivial, non-self-averaging, overlap probability distribution when the impurity concentration vanishes in the thermodynamic limit. The form of the distribution can be calculated analytically for any realization of disorder. For non-zero impurity concentr

Petr Kurka

We argue that simple dynamical systems are factors of finite automata, regarded as dynamical systems on discontinuum. We show that any homeomorphism of the real interval is of this class. An orientation preserving homeomorphism of the circle is a factor of a finite automaton iff its rotation number is rational. Any $S$-unimodal system on the real interval, w

G. Cicogna, L. Fronzoni

We analyze, by means of Melnikov method, the possibility of modifying the threshold of homoclinic chaos in general 1-dimensional problems, by introducing small periodic resonant modulations. We indicate in particular a prescription in order to increase the threshold (i.e. to prevent chaos), and consider then its application to the bistable Duffing-Holmes pot

Shude Mao, Ramesh Narayan, Tsvi Piran

Kouveliotou et al. (1993) recently confirmed that gamma-ray bursts are bimodal in duration. In this paper we compute the statistical properties of the short ($\le 2$~s) and long ($>2$~s) bursts using a method of analysis that makes no assumption regarding the location of the bursts, whether in the Galaxy or at a cosmological distance. We find the 64 ms chann

Eyal Maoz

If a substantial fraction of the observed gamma-ray bursts originates within an extended Galactic halo then their spatial distribution should deviate slightly from spherical symmetry in a very particular way which involves features both in the bursts&#39; angular and radial distributions. This conclusion is based on various reasons which are all related to t

W. A. Beck, L. Wilets, M. A. Alberg

A semi-classical, many-body atomic model incorporating a momentum-dependent Heisenberg core to stabilize atomic electrons is used to study antiproton capture on Helium. Details of the antiproton collisions leading to eventual capture are presented, including the energy and angular momentum states of incident antiprotons which result in capture via single or

L. D. Skouras, H. Müther, M. A. Nagarajan

The structure of $^6$Li, $^7$Li and $^{11}$Li nuclei is investigated in a model space which includes all configurations with oscillator energy up to $3\hbarω$ above the ground state configuration. The energy spectra and electromagnetic properties of the low-lying states are determined with various two-body interactions, which are derived from the Bonn potent

Saharon Shelah

We show in section 1 that the Ax-Kochen isomorphism theorem requires the continuum hypothesis. Most of the applications of this theorem are insensitive to set theoretic considerations. (A probable exception is the work of Moloney.) In section 2 we give an unrelated result on cuts in models of Peano arithmetic which answers a question on the ideal structure o

Garvin Melles

This paper is a technical continuation of ``Natural Axiom Schemata Extending ZFC. Truth in the Universe?&#39;&#39; In that paper we argue that $CIFS$ is a natural axiom schema for the universe of sets. In particular it is a natural closure condition on $V$ and a natural generalization of $IFS(L).$ Here we shall prove the consistency of $ZFC\ +\ CIFS$ relativ

Jim Stasheff

This is an expanded and updated version of a talk given at the Conference on Topics in Geometry and Physics at the University of Southern California, November 6, 1992. It is a survey talk, aimed at mathematicians AND physicists, which attempts to bring together the topics in the title without assuming much background in any of them. Closed string field theor

Joshua Feinberg

The one dimensional Fermi gas of matrix eigenvalues of the Marinari-Parisi model at positive values of the cosmological constant is generalised.The number of matrix eigenvalues (i.e. gas particles) is varied while keeping the effective potential fixed. This model exhibits a transition from a phase whose continuum behaviour is that of $c=1$ conformal matter c

K. Ikegami

I consider a Langevin equation with field-dependent kernels and investigate supersymmetry of the stochastic generating functional constructed from the Langevin equation. Moreover I describe the stochastic generating functional in terms of a superfield. In the superfield formalism, it becomes clear that the stochastic quantization method with the field-depend

Markus A. Luty, Raman Sundrum

The $SU(3)$-violating decays $Φ^{2S} \goto Φ^{1S} X$, where $X = π^0$ or $η$ and $Φ= J/ψ$ or $Υ$ have been recently proposed as a means of probing the light quark masses beyond leading order in chiral perturbation theory. We argue that this analysis is incorrect, even in the heavy quark limit. We show that these decays are governed by an infinite number of m

M. Ciuchini, E. Franco, G. Martinelli, L. Reina

In this paper we present a calculation of the $ΔS=1$ effective weak Hamiltonian including next-to-leading order QCD and QED corrections. At a scale $μ$ of the order of few GeV, the Wilson coefficients of the operators are given in terms of the renormalization group evolution matrix and of the coefficients computed at a large scale $\sim M_W$. The expression

Yves Brihaye, Jutta Kunz

We consider non-perturbative solutions of the Weinberg-Salam model at finite temperature. We employ an effective temperature-dependent potential yielding a first order phase transition. In the region of the phase transition, there exist two kinds of static, spherically symmetric solutions: sphalerons and bubbles. We analyze these solutions as functions of te

A. Lopez-Fernandez, J. C. Romão, F. de Campos, J. W. F. Valle

We derive model-independent constraints on Higgs mass and couplings from associated signals for higher masses, accessible at LEP2. This work is motivated by the fact that, in many extensions of the standard model, the Higgs boson can have substantial &#34;invisible&#34; decay modes, for example, into light or massless weakly interacting Goldstone bosons asso

C. Glenn Boyd, David E. Brahm, Stephen D. H. Hsu

We examine several resummation methods for computing higher order corrections to the finite temperature effective potential, in the context of a scalar $ϕ^4$ theory. We show by explicit calculation to four loops that dressing the propagator, not the vertex, of the one-loop tadpole correctly counts ``daisy&#39;&#39; and ``super-daisy&#39;&#39; diagrams.

David F. Chernoff, Lee Samuel Finn

We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise e

Lars Andersson, Piotr T. Chrusciel

Various works have suggested that the Bondi--Sachs--Penrose decay conditions on the gravitational field at null infinity are not generally representative of asymptotically flat space--times. We have made a detailed analysis of the constraint equations for ``asymptotically hyperboloidal&#39;&#39; initial data and find that log terms arise generically in asymp

A Crisanti, G Paladin, M Serva, A Vulpiani

Products of random transfer matrices are applied to low dimensional disordered systems to evaluate numerically extensive quantities such as entropy and overlap probability distribution. The main advantage is the possibility to avoid numerical differentiation. The method works for arbitrary disorder distributions at any temperature.

D. P. Bennett

MAssive Compact Halo Objects such as brown dwarfs, Jupiters, and black holes are prime candidates to comprise the dark halo of our galaxy. Paczynski noted that objects (dubbed MACHOs) with masses in the range $10^{-6}M_\odot < M \simlt 100 M_\odot$. can be detected via gravitational microlensing of stars in the Magellanic Clouds with the caveat that only abo

Rinat Kedem, Barry M. McCoy, Ezer Melzer

We discuss the relation of the two types of sums in the Rogers-Schur-Ramanujan identities with the Bose-Fermi correspondence of massless quantum field theory in $1+1$ dimensions. One type, which generalizes to sums which appear in the Weyl-Kac character formula for representations of affine Lie algebras and in expressions for their branching functions, is re

G. Barnich, M. Henneaux

The antibracket in BRST theory is known to define a map $\rm{H^p \times H^q \longrightarrow H^{p+q+1}}$ associating with two equivalence classes of BRST invariant observables of respective ghost number p and q an equivalence class of BRST invariant observables of ghost number p+q+1. It is shown that this map is trivial in the space of all functionals, i.e.,

M. A. Shifman

Invited Talk at the Conference &#34;QCD -- 20 Years Later&#34;, June 9 - 13, 1992, Aachen, Germany

Neven Bilic, Branko Guberina

Rare kaon processes appear to be particularly suitable to study the extensions of the standard model, especially if the possibility for eventual direct evidence becomes unlikely. In this review, we discuss processes that are important as a test of either the standard model or supergravity. Moreover, some of these are important even for both the standard mode

K. V. L. Sarma

Absract (Invited talk at the X DAE High Energy Physics symposium in December 1992, held at Tata Institute of Fundamental Research, Bombay)

F. Karsch, E. Laermann

Numerical simulations have become an important tool to understand and predict non-perturbative phenomena in particle physics. In this article we attempt to present a general overview over the field. First, the basic concepts of lattice gauge theories are described, including a discussion of currently used algorithms and the reconstruction of continuum physic

L. P. Grishchuk

It is shown that only a narrow class of inflationary models can possibly agree with the available observational data on the anisotropy of the cosmic microwave background radiation (CMBR). These models may be governed by ``matter&#39;&#39; with the effective equation of state $-1.2 <p/ ε< -0.6$ which includes the De-Sitter case $p/ ε= -1$.

Piotr Koc

We continue the investigation of formation of trapped surfaces in strongly curved , conformally flat geometries. Initial data in quasi-polar gauges rather then maximal ones are considered. This implies that apparent horizons coincide with minimal surfaces. Necessary and sufficient conditions for the formation of trapped surfaces are given. These results can