February 1994 arXiv papers — page 6

Frank Steiner

A short historical overview is given on the development of our knowledge of complex dynamical systems with special emphasis on ergodicity and chaos, and on the semiclassical quantization of integrable and chaotic systems. The general trace formula is discussed as a sound mathematical basis for the semiclassical quantization of chaos. Two conjectures are pres

J. M. Paredes, P. Marziani, J. Marti, J. Fabregat

We present new optical and infrared photometric observations and high resolution H$α$ spectra of the periodic radio star \lsi. The optical photometric data set covers the time interval 1985-1993 and amounts to about a hundred nights. A period of $\sim$26 days is found in the V band. The infrared data also present evidence for a similar periodicity, but with

A. Borisov

The main purpose of this article is to prove that the family of all Fano threefolds with log-terminal singularities with bounded index is bounded.

J. K. Freericks

Conserving approximations are applied to the attractive Holstein and Hubbard models (on an infinite-dimensional hypercubic lattice). All effects of nonconstant density of states and vertex corrections are taken into account in the weak-coupling regime. Infinite summation of certain classes of diagrams turns out to be a quantitatively less accurate approximat

Konstadinos Sfetsos

We consider WZW models based on the non-semi-simple algebras that they were recently constructed as contractions of corresponding algebras for semi-simple groups. We give the explicit expression for the action of these models, as well as for a generalization of them, and discuss their general properties. Furthermore we consider gauged WZW models based on the

T. Inagaki

In composite Higgs models it was pointed out that there is a possibility to violate CP symmetry dynamically. We demonstrated a simple model of dynamical CP violation in composite Higgs models. We calculated the neutron electric dipole moment in our model and the constraint for our model is discussed. (Talk presented at the Third KEK Topical Conference on CP

I. V. Lerner

It is shown that the distribution functions of the diffusion coefficient are very similar in the standard model of quantum diffusion in a disordered metal and in a model of classical diffusion in a disordered medium: in both cases the distribution functions have lognormal tails, their part increasing with the increase of the disorder. The similarity is based

A. G. Aronov, V. E. Kravtsov, I. V. Lerner

For a disordered system near the Anderson transition we show that the nearest-level-spacing distribution has the asymptotics $P(s)\propto \exp(-A s^{2-γ})$ for $s\gg \av{s}\equiv 1$ which is universal and intermediate between the Gaussian asymptotics in a metal and the Poisson in an insulator. (Here the critical exponent $0<γ<1$ and the numerical coefficient

V. E. Kravtsov, I. V. Lerner, B. L. Altshuler, A. G. Aronov

We demonstrate the level statistics in the vicinity of the Anderson transition in $d>2$ dimensions to be universal and drastically different from both Wigner-Dyson in the metallic regime and Poisson in the insulator regime. The variance of the number of levels $N$ in a given energy interval with $\langle N\rangle\gg1$ is proved to behave as $\langle N\rangle

David O. Caldwell, Rabindra N. Mohapatra

Neutrino mass explanations of the solar and atmospheric neutrino deficits and a hot dark matter component require one of three patterns of those masses, as already pointed out by us. Recently there have been indications of a non-vanishing amplitude for neutrinoless double beta decay. If this additional hint of neutrino mass is true, it would make even less l

A. S. Cattaneo, A. Gamba, M. Martellini

We show that introducing a periodic time coordinate in the models of Penner-Kontsevich type generalizes the corresponding constructions to the case of the moduli space ${\cal S}_{gn}^k$ of curves $C$ with homology chains $γ\in H_1(C,\zet_k)$. We make a minimal extension of the resulting models by adding a kinetic term, and we get a new matrix model which rea

Klaus Krebs, Markus Pfannmueller, Birgit Wehefritz

The finite-size scaling function and the leading corrections for the single species 1D coagulation model $(A + A \rightarrow A)$ and the annihilation model $(A + A \rightarrow \emptyset)$ are calculated. The scaling functions are universal and independent of the initial conditions but do depend on the boundary conditions. A similarity transformation between

P. Bamert, C. P. Burgess

The solar neutrino problem, atmospheric neutrino problem, and the existence of hot dark matter can all be economically accounted for using only the three known neutrinos if these neutrinos all have nearly degenerate masses of a few eV. We show how to generate this pattern of neutrino masses in a natural way within a `see-saw&#39; framework.

S. M. Roy, Virendra Singh

Present quantum theory, which is statistical in nature, does not predict joint probability distribution of position and momentum because they are noncommuting. We propose a deterministic quantum theory which predicts a joint probability distribution such that the separate probability distributions for position and momentum agree with usual quantum theory. Un

I. Bigi, M. Shifman, N. Uraltsev, A. Vainshtein

We show that the phenomenological \ACM ansatz is consistent with QCD through order $1/m_b$ in the description of $B\ra l\bar ν_l+X_u$ and $B\ra γ+X_s$ transitions, including their energy spectra and differential distributions. This suggests a concrete realization for the QCD distribution function, which we call the ``Roman&#39;&#39; function. On the other ha

Andras Szenes

A residue formula is given for the Verlinde formula, which allows one to calculate its coefficients as a polynomial in the level and connects it to the Riemann-Roch formula on the moduli space of vector bundles on a curve.

A. Bayliss, B. J. Matkowsky, H. Riecke

We describe spatial and temporal patterns in cylindrical premixed flames in the cellular regime, $Le < 1$, where the Lewis number $Le$ is the ratio of thermal to mass diffusivity of a deficient component of the combustible mixture. A transition from stationary, axisymmetric flames to stationary cellular flames is predicted analytically if $Le$ is decreased b

Jorge G. Hirsch, Octavio Castaños, Peter O. Hess

The most important features of the pseudo SU(3) model are reviewed. This description of heavy deformed nuclei is based on pseudo spin symmetry, and is able to correctly predict the collective spectra and their transition amplitudes, using appropriate effective charges. It also gives a very good description of the exotic double beta decay, a hard test of any

R. Bijker, F. Iachello, A. Leviatan

We introduce an algebraic framework for the description of baryons. Within this framework we study a collective string-like model and show that this model gives a good overall description of the presently available data. We discuss in particular masses and electromagnetic couplings, including the transition form factors that can be measured at new electron f

B. Blankleider, A. N. Kvinikhidze

The unitary NN-piNN model contains a serious theoretical flaw: unitarity is obtained at the price of having to use an effective piNN coupling constant that is smaller than the experimental one. This is but one aspect of a more general renormalization problem whose origin lies in the truncation of Hilbert space used to derive the equations. Here we present a

A. N. Kvinikhidze, B. Blankleider

We derive four-dimensional relativistic three-body equations for the case of a field theory with a three-point interaction vertex. These equations describe the coupled 2->2, 2->3, and 3->3 processes, and provide the means of calculating the kernel of the 2->2 Bethe-Salpeter equation. Our equations differ from all previous formulations in two essential ways.

A. Bassetto, F. De Biasio, L. Griguolo

A light-like Wilson loop is computed in perturbation theory up to ${\cal O} (g^4)$ for pure Yang--Mills theory in 1+1 dimensions, using Feynman and light--cone gauges to check its gauge invariance. After dimensional regularization in intermediate steps, a finite gauge invariant result is obtained, which however does not exhibit abelian exponentiation. Our re

C. P. Korthals-Altes

The spontaneous breaking of Z(N) symmetry in hot QCD and the appearance of domain walls is reviewed.

T. Gannon, Q. Ho-Kim

In this paper, we develop several general techniques to investigate modular invariants of conformal field theories whose algebras of the holomorphic and anti-holomorphic sectors are different. As an application, we find all such ``heterotic&#39;&#39; WZNW physical invariants of (horizontal) rank four: there are exactly seven of these, two of which seem to be

Kazuhiro Hikami, Miki Wadati

Nonlinear integrable equations, such as the KdV equation, the Boussinesq equation and the KP equation, have the close relation with many-body problem. The solutions of such equations are the same as the restricted flows of the classical Calogero model, which is one-dimensional particle system with inverse square interactions. The KP hierarchy and the Caloger

A. P. Isaev, A. A. Vladimirov

We study a possibility to define the (braided) comultiplication for the GLq(N)-covariant differential complexes on some quantum spaces. We discover such `differential bialgebras&#39; (and Hopf algebras) on the bosonic and fermionic quantum hyperplanes (with additive coproduct) and on the braided matrix algebra BMq(N) with both multiplicative and additive cop

Kentaro Hori

This is a thesis for Rigaku-Hakushi($\simeq$ Ph. D.). It clarifies the geometric meaning and field theoretical consequences of the spectral flows acting on the space of states of the `$G/H$ coset model&#39;. As suggested by Moore and Seiberg, the spectral flow is realized as the response of states to certain change of background gauge field together with the

Jin Dai, James Hughes

We evaluate the next-to-leading order radiative corrections to a process in the massless Schwinger model that is the analogue of the $e^+e^-$ inclusive annihilation into hadrons process in QCD. We then carry out an asymptotic expansion of the calculable exact result and find that it agrees with the perturbative answer. However, we also find that higher order

Toby Falk, Richard Madden, Keith A. Olive, Mark Srednicki

We calculate the one-loop contribution to the bino annihilation rate due to the process $\widetilde B \widetilde B \to Z^*$, which vanishes at tree level.

Luis E. Ibanez

I discuss some new trends in particle theory beyond the standard model. Some topics briefly covered include elecroweak baryogenesis, gauge versus non-gauge discrete symmetries, the strong CP problem, dynamical symmetry breaking scenarios, supersymmetric grand unification, new aspects in low energy supersymmetry and superstring phenomenology.

A. C. Mattingly

We apply the optimization procedure based on the Principle of Minimal Sensitivity to the third-order calculation of $R_τ$. Since the effective couplant remains finite, freezing to a value $α_s/π= 0.26$ at low energies, we can actually evaluate the defining integral of $R_τ$ and compare the optimized perturbation theory result to that of the optimized result

Derek B. Leinweber

Strange quark contributions to the proton magnetic moment are estimated from a consideration of baryon magnetic moment sum rules. The environment sensitivity of quark contributions to baryon moments is emphasized. Pion cloud contributions to proton charge radii are examined in the framework of Chiral Perturbation Theory. The absence of scalar-diquark cluster

G. Kramer, W. F. Palmer, H. Simma

We calculate direct CP-violating observables in charged $B\to VV$ decays arising from the interference of amplitudes with different strong and CKM phases. The perturbative strong phases develop at order $α_s$ from absorptive parts of one-loop matrix elements of the next-to-leading logarithm corrected effective Hamiltonian. CPT constraints are maintained. Bas

J. Lopez, D. Nanopoulos, A. Zichichi

We show that the currently experimentally preferred values of the top-quark mass (\ie, $130\lsim m_t\lsim180\GeV$) are naturally understood in the context of string models, where the top-quark Yukawa coupling at the string scale is generically given by $λ_t={\cal O}(g)$, with $g$ the unified gauge coupling. A detailed study of the Yukawa sector of $SU(5)\tim

W. Beirl, E. Gerstenmayer, H. Markum, J. Riedler

We analyze simplicial quantum gravity in four dimensions using the Regge approach. The existence of an entropy dominated phase with small negative curvature is investigated in detail. It turns out that observables of the system possess finite expectation values although the Einstein-Hilbert action is unbounded. This well-defined phase is found to be stable f

Curt Cutler, Eanna Flanagan

The most promising source of gravitational waves for the planned detectors LIGO and VIRGO are merging compact binaries, i.e., neutron star/neutron star (NS/NS), neutron star/black hole (NS/BH), and black hole/black-hole (BH/BH) binaries. We investigate how accurately the distance to the source and the masses and spins of the two bodies will be measured from

Gérard Clément

We construct time-dependent multi-centre solutions to three-dimensional general relativity with zero or negative cosmological constant. These solutions correspond to dynamical systems of freely falling black holes and conical singularities, with a multiply connected spacetime topology. Stationary multi-black-hole solutions are possible only in the extreme bl

F. W. Hehl, J. D. McCrea, E. W. Mielke, Y. Ne&#39;eman

In Einstein&#39;s gravitational theory, the spacetime is Riemannian, that is, it has vanishing torsion and vanishing nonmetricity (covariant derivative of the metric). In the gauging of the general affine group ${A}(4,R)$ and of its subgroup ${GL}(4,R)$ in four dimensions, energy--momentum and hypermomentum currents of matter are canonically coupled to the o

X. G. Wen, A. Zee

The $(kkk)$ double layered quantum Hall state has been shown to exhibit many superfluid properties including the appearance of an alternating tunnelling current in response to an external voltage V. Here we propose the notion of &#34;sideways tunnelling&#34;, in which a current tunnels between two such $(kkk)$ states through an incompressible fractional quan

A. G. Abanov, O. A. Petrenko

It is shown that the observed anisotropy of magnetization at high magnetic fields in RbMnBr3 , a quasi-one-dimensional antiferromagnet on a distorted stacked triangular lattice, is due to quantum and thermal fluctuations. These fluctuations are taken into account in the framework of linear spin-wave theory in the region of strong magnetic fields. In this reg

Gene F. Mazenko, Joonhyun Yeo

Mode coupling theory (MCT) has been successful in explaining the observed sequence of time relaxations in dense fluids. Previous expositions of this theory showing this sequence have required the existence of an ideal glass transition temperature $T_0$. Recent experiments show no evidence of $T_0$. We show here how the theory can be reformulated, in a fundam

Gene F. Mazenko, Joonhyun Yeo

We study the role of the Jacobian arising from a constraint enforcing the nonlinear relation: ${\bf g}=ρ{\bf V}$, where $ρ,\: {\bf g}$ and ${\bf V}$ are the mass density, the momentum density and the local velocity field, respectively, in the field theoretic formulation of the nonlinear fluctuating hydrodynamics of simple fluids. By investigating the Jacobia

Min-Chul Cha, H. A. Fertig

We study the ground state of two-dimensional classical electron solids under the influence of modulation-doped impurities by using a simulated annealing molecular dynamics method. By changing the setback distance as a parameter, we find that in the strong disorder limit the ground state configuration contains both isolated dislocations and disclinations, whe

V. Rittenberg

The master equation describing non-equilibrium one-dimensional problems like diffusion limited reactions can be written as a euclideen Schrödinger equation in which the wave function is the probability distribution and the Hamiltonian is that of a quantum chain with nearest-neighbour interactions. Since many one-dimensional chains are integrable, this opens

Klaus Krebs, Markus Pfannmueller, Horatiu Simon, Birgit Wehefritz

The scaling exponent and scaling function for the 1D single species coagulation model $(A+A\rightarrow A)$ are shown to be universal, i.e. they are not influenced by the value of the coagulation rate. They are independent of the initial conditions as well. Two different numerical methods are used to compute the scaling properties: Monte Carlo simulations and

Haye Hinrichsen, Klaus Krebs, Markus Pfannmueller, Birgit Wehefritz

We consider the coagulation-decoagulation model on an one-dimensional lattice of length $L$ with open boundary conditions. Based on the empty interval approach the time evolution is described by a system of $\frac{L(L+1)}{2}$ differential equations which is solved analytically. An exact expression for the concentration is derived and its finite-size scaling

S. Dukan, Z. Tesanovic

The quasiparticle excitation spectrum of a type-II superconductor placed in high magnetic field is shown to be gapless. The gap turns to zero at the points in the MBZ which are in correspondence with the vortex lattice in real space. When the field decreases below certain critical value, branch crossing occur and gaps starts opening up at the Fermi surface.T

S. Giorgini, L. Pitaevskii, S. Stringari

We discuss the effects of a weak random external potential on the properties of the dilute Bose gas at zero temperature. The results recently obtained by Huang and Meng for the depletion of the condensate and of the superfluid density are recovered. Results for the shift of the velocity of sound as well as for its damping due to collisions with the external

Guinevere Kauffmann, Stéphane Charlot

There is accumulating observational evidence suggesting that damped Ly$α$ absorption systems systems are the progenitors of present-day spiral galaxies. We use the observed properties of these systems to place constraints on the history of star formation in galactic disks, and on cosmological theories of structure formation in the universe. We show that the

H. J. Mo, J. Miralda-Escude

We examine the constraints on theories of galaxy formation that are obtained from observations of damped $\lya$ (DL) systems, assuming they are gaseous protodisks in dark matter halos. Using the Press-Schechter formalism, we find that the mixed dark matter model, with $\ohdm = 0.3$, $\ocdm = 0.65$, $\obaryon = 0.05$, and $h=0.5$, is ruled out because the num

Wolfgang J. Duschl, Harald Lesch

We demonstrate that there is only one physical process required to explain the spectrum and the variability of the radio source at the dynamical center of our Galaxy, Sgr A*, in the frequency range from $\approx$1 to $\approx$1000 GHz, namely optically thin synchrotron radiation that is emitted from a population of relativistic electrons. We attribute the ob

Robert J. Nemiroff

More than 100 gamma-ray burst progenitor models have now been published in refereed journals. A list of the models published before the end of 1992 is presented and briefly discussed. The consensus of the present astronomical community remains that no specific model is particularly favored for cosmic bursts. Recent BATSE results make most of these models unt

Boris Feigin, Edward Frenkel, Nikolai Reshetikhin

We propose a new method of diagonalization of hamiltonians of the Gaudin model associated to an arbitrary simple Lie algebra, which is based on Wakimoto modules over affine algebras at the critical level. We construct eigenvectors of these hamiltonians by restricting certain invariant functionals on tensor products of Wakimoto modules. In conformal field the

J. L. Alonso, F. Lesmes, E. Rivas, Ph. Boucaud

We present the phase structure of the chiral SU(2)xSU(2) scalar-fermion model on the lattice using the Zaragoza proposal for chiral fermions. The numerical result agrees with an analytic study based on the use of weak and strong Yukawa coupling expansions combined with the mean field approach. The phase diagram consits of four phases: paramagnetic(PM), ferro

S. E. Koonin, K. Langanke

We show that the presently available data on the Gamow-Teller (GT) strength in mid-fp-shell nuclei are proportional to the product of the numbers of valence protons and neutron holes in the full fp-shell. This observation leads to important insights into the mechanism for GT quenching and to a simple parametrization of the Gamow-Teller strengths important fo

E. Nardi, E. Roulet, D. Tommasini

We study the effects induced by new neutral fermions below their mass threshold, due to their possible mixing with the standard neutrinos. We use as experimental constraints the recent results on lepton universality, together with the measurement of the $μ$ decay rate and the updated LEP data. In particular, the inclusion in our data set of the most recent d

K. Huitu, J. Maalampi, M. Raidal

The pair production of sleptons in electron-positron collisions is investigated in a supersymmetric left-right model. The cross section is found considerably larger than in the minimal supersymmetric version of the Standard Model (MSSM) because of more contributing graphs. A novel process is a doubly charged higgsino exchange in u-channel, which makes the an

Karl-Peter Marzlin

(Some Latex problems should be removed in this version) Fermi coordinates (FC) are supposed to be the natural extension of Cartesian coordinates for an arbitrary moving observer in curved space-time. Since their construction cannot be done on the whole space and even not in the whole past of the observer we examine which construction principles are responsib

D. Bonatsos, C. Daskaloyannis, D. Ellinas, A. Faessler

The ``position'' and ``momentum'' operators for the q-deformed oscillator with q being a root of unity are proved to have discrete eigenvalues which are roots of deformed Hermite polynomials. The Fourier transform connecting the ``position'' and ``momentum'' representations is also found The phase space of this oscillator has a lattice structure, which is a

Miroslav Doresic, Stjepan Meljanac, Marijan Milekovic

We define a class of deformed multimode oscillator algebras which possess number operators and can be mapped to multimode Bose algebra.We construct and discuss the states in the Fock space and the corresponding number operators.

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

Covariantly we reformulate the description of a spinning particle in terms of the Poincaré group. We also construct a Lagrangian which entails all possible constraints explicitly; all constraints can be obtained just from the Lagrangian. Furthermore, in this covariant reformulation, the Lorentz element is to be considered to evolve the momentum or spin compo

W. Koepf, L. Wilets, S. Pepin, Fl. Stancu

We study the N-N interaction in the framework of the chromo-dielectric soliton model. Here, the long-range parts of the nonabelian gluon self-interactions are assumed to give rise to a color-dielectric function which is parameterized in terms of an effective scalar background field. The six-quark system is confined in a deformed mean field through an effecti

R. Cenni, P. Saracco

A scaling variable for electron scattering off nuclei in the Delta-region is shown to exist. A scaling law for a large variety of scattering data with different kinematics is found. This property turns out to be very sensitive to the reaction mechanism. We will show that this outcome follows from drastic medium induced modifications on the momentum and energ

D. J. Dean, P. B. Radha, K. Langanke, Y. Alhassid

Gamow-Teller strengths for selected nuclei in the iron region (A~56) have been investigated via shell-model Monte Carlo calculations with realistic interactions in the complete fp basis. Results for all cases show significant quenching relative to single-particle estimates, in quantitative agreement with (n,p) data. The J=1,T=0 residual interaction and the f

Luca Lusanna

A canonical basis of global Dirac&#39;s observables for Yang-Mills theory with fermions are obtained in a functional space in which Gribov ambiguity is absent and Gauss&#39; laws can be solved exactly. In terms of these observables, one can express the Lagrangian, the Hamiltonian, non-Abelian and topological charges. The problem of the covariantization of th

Takahiro Shiota

The space of solutions of the rational Calogero-Moser hierarchy, and the space of solutions of the KP hierarchy whose tau functions are monic polynomials in $t_1$ with coefficients depending on $t_n$, $n > 1$, are identified, generalizing earlier results of Airault-McKean-Moser and Krichever.

G. Amelino-Camelia

Bosonic end perturbative calculations for quantum mechanical anyon systems require a regularization. I regularize by adding a specific $δ$-function potential to the Hamiltonian. The reliability of this regularization procedure is verified by comparing its results for the 2-anyon in harmonic potential system with the known exact solutions. I then use the $δ$-

Thomas Kerler

We investigate invertible elements and gradings in braided tensor categories. This leads us to the definition of theta-, product-, subgrading and orbitcategories in order to construct new families of BTC&#39;s from given ones. We use the representation theory of Hecke algebras in order to relate the fusionring of a BTC generated by an object $X$ with a two c

Thomas Kerler

We study representations of the mapping class group of the punctured torus on the double of a finite dimensional possibly non-semisimple Hopf algebra that arise in the construction of universal, extended topological field theories. We discuss how for doubles the degeneracy problem of TQFT&#39;s is circumvented. We find compact formulae for the ${\cal S}^{\pm

I. Bakas

The 1--loop string background equations with axion and dilaton fields are shown to be integrable in four dimensions in the presence of two commuting Killing symmetries and $δc = 0$. Then, in analogy with reduced gravity, there is an infinite group that acts on the space of solutions and generates non--trivial string backgrounds from flat space. The usual $O(

Robert J. Perry

A perturbative renormalization group is formulated for the study of Hamiltonian light-front field theory near a critical Gaussian fixed point. The only light-front renormalization group transformations found that can be approximated by dropping irrelevant operators and using perturbation theory near Gaussian fixed volumes, employ invariant-mass cutoffs. Thes

N. I. Ussyukina, A. I. Davydychev

A number of exact results for two-loop three-point diagrams with massless internal particles and arbitrary (off-shell) external momenta are presented. Divergent contributions are calculated in the framework of dimensional regularization.

J. C. D&#39;Olivo, J. F. Nieves, M. Torres, E. Tututi

We argue that calculations in QED at finite temperature are more conveniently carried out in the Coulomb gauge, in which only the physical photon degrees of freedom play a rol and are thermalized. We derive the photon propagator in this gauge for real-time finite temperature calculations and show that the four-fermion static Coulomb interaction that appears

U. Ellwanger, C. Wetterich

Evolution equations describe the effect of consecutively integrating out all quantum fluctuations with momenta larger than some infrared cutoff scale k. We develop a formalism for the introduction of collective degrees of freedom at some intermediate scale and derive the corresponding evolution equations. This allows to account for the appearance of bound st

A. E. Kaloshin, V. M. Persikov, V. V. Serebryakov

We carry out the semi--model analysis of existing data on the angular distributions of the $γγ\rightarrowπ^+ π^- ,\ π^0 π^0$ reactions with purpose to obtain S-wave cross section and D-wave&#39;s parameters. In the first time we obtain from experiment the sum of electrical and magnetic pion polarizabilities: $(α+ β)^{π^+} = 0.28 \pm 0.07$ (MARK-II \cite{M2})

Michael A. Earnshaw, Warren B. Perkins

A solution of the standard electroweak theory with a single lepton family is constructed, consisting of a cosmic string and a fermion condensate within its core. The stability of this system to small perturbations is examined, and it is found that stability is not enhanced relative to the bare electroweak string. The presence of quark zero modes is shown to

Edi Halyo

We investigate the R symmetries of standard--like superstring models. At the level of the cubic superpotential there are three global $U(1)$ R symmetries. These are broken explicitly by $N>3$ terms in the superpotential and spontaneously by scalar VEVs necessary to preserve supersymmetry at $M_P$. A $Z_2$ discrete symmetry remains but is equivalent to fermio

P. Heiliger, B. McKellar, L. M. Sehgal

The decays $K_{L,S} \to 3 γ$ are not forbidden by any selection rules or symmetry principles. However, gauge invariance and Bose statistics dictate that every photon pair in these transitions has at least two units of angular momentum. This gives rise to an extraordinary suppression. Using a simple model, we obtain the branching ratios $B(K_L \to 3 γ) \sim 3

V. Berezinsky, A. Bottino, G. Mignola

We study the NGS (Non--dissipative Gravitational Singularity) model, which successfully describes the non--linear stage of evolution of perturbations (see [1], [2] and references therein). This model predicts DM density distribution $ρ(r) \sim r^{-α}$ with $α\simeq 1.8$ which holds from very small distances $r_{\rm min} \simeq 0.01~{\rm pc}$ up to very large

Stanley J. Brodsky, Felix Schlumpf

We calculate the proton&#39;s magnetic moment $μ_p$ and its axial-vector coupling $g_A$ as a function of its Dirac radius $R_1$ using a relativisitic three-quark model formulated on the light-cone. The relationship between $μ_p$ and $g_A$ is found to be independent of the assumed form of the light-cone wavefunction. At the physical radius $R_1=0.76$ fm, one

Wojciech H. Zurek

Selection of the preferred classical set of states in the process of decoherence -- so important for cosmological considerations -- is discussed with an emphasis on the role of information loss and entropy. {\it Persistence of correlations} between the observables of two systems (for instance, a record and a state of a system evolved from the initial conditi

L. Vanzo, G. Turco

The grand-canonical thermodynamic potential for Bose and Fermi fields in anti-de Sitter space-time is introduced and a Mellin complex representation is given. This is used to investigate the high temperature properties of the thermal state at finite charge. The time-like nature of spatial infinity is shown to act as a boundary, and changes the free energy of

M. S. Deshpande, E. J. Mele, M. J. Rice, H-Y Choi

The coupling between the intramolecular vibrational modes and the doped conduction electrons in $M_3C_{60}$ is studied by a calculation of the electronic contributions to the phonon self energies. The calculations are carried out for an orientationally ordered reference solid with symmetry $Fm \bar{3} m$ and for a model with quenched orientational disorder o

Zoltan NEDA

Using the Swendsen and Wang algorithm, high accuracy Monte Carlo simulations were performed to study the concentration dependence of the Curie temperature in binary, ferromagnetic Ising systems on the simple-cubic lattice. Our results are in good agreement with known mean-field like approaches. Based on former theoretical formulas we propose a new way of est

K. Vacek, A. Okiji, N. Kawakami

We find a set of the exact eigenfunctions which provide the energy spectrum for the quantum $N$-body Calogero-Sutherland model for fermions or bosons with SU($ν$) spin degrees of freedom moving in a harmonic confinement potential. The eigenfunctions are explicitly constructed as a simple product of the Jastrow wave function for the ground state and the Hermi

Norio Kawakami

We review recent results obtained for a class of one-dimensional quantum models with $1/r^2$ long-range interaction. Based on the asymptotic Bethe-ansatz solution and conformal field theory, we study critical properties of the continuum boson model, the SU($ν$) spin chain, the OSp($ν$,1) supersymmetric {\it t-J} model, and a new hierarchy of models related t

Nicholas D. Socci, William S. Bialek, Jose&#39; Nelson Onuchic

Proteins contain a large fraction of regular, repeating conformations, called secondary structure. A simple, generic definition of secondary structure is presented which consists of measuring local correlations along the protein chain. Using this definition and a simple model for proteins, the forces driving the formation of secondary structure are explored.

Y. Kuramoto

Excitation spectra in the SU($ν+1$,1) supersymmetric t-J model with long-range exchange and transfer has quadratic dependence on spin and charge currents for all energies. After brief review on the supersymmetry, this paper gives a simple explanation for the spin-charge separation on the basis of a first-quantized representation. A useful identity is derived

Xingming Chen, Ronald E. Taam

We consider the inner regions of accretion disks surrounding black holes and neutron stars and investigate the nonlinear time dependent evolution of thermal-viscous instabilities. The viscous stress is assumed to be proportional to the gas pressure with the viscosity parameter formulated as $α=\min[α_0 (h/r)^n, α_{\max}]$, where $h$ is the local scale height

Peter J. Kernan, Lawrence M. Krauss

We include correlations between elemental abundances in a Monte Carlo statistical analysis of BBN predictions, which, along with updated reaction rates and an improved BBN code, lead to tightened constraints on $Ω_{B}$ and $N_ν$. Observational upper limits on the primordial \he and $\rm {D + {^3He}}$ fractions of $24 \%$ (by weight) and $ 10^{-4}$ respective

Ben Moore

Collisionless particles, such as cold dark matter, interact only by gravity and do not have any associated length scale, therefore the dark halos of galaxies should have negligible core radii. This expectation has been supported by numerical experiments of collisionless particles within scale free and cold dark matter cosmologies. Most dwarf spiral galaxies

Victor V. Batyrev, Lev A. Borisov

We introduce a special class of convex rational polyhedral cones which allows to construct generalized Calabi-Yau varieties of dimension $(d + 2(r-1))$, where $r$ is a positive integer and d is the dimension of critical string vacua with central chatge $c = 3d$. It is conjectured that the natural combinatorial duality satisfies by these cones corresponds to

Atanas Iliev

Let T be a general bidegree (2,2) divisor in the product of two projective planes. Recently A.Verra proved that the existence of two conic bundle structures (c.b.s.) on T implies a new counterexample to the Torelli theorem for Prym varieties. Let J(T) be the jacobian of T. In this paper we prove that any of the two c.b.s. on T admits a parametrisation of the

Yong-Shi Wu

Misprints in eq. (7), which propagate up to eq. (13), are corrected. References are updated.

Wojciech Hubert Zurek, Juan Pablo Paz

We investigate implications of decoherence for quantum systems which are classically chaotic. We show that, in open systems, the rate of von Neumann entropy production quickly reaches an asymptotic value which is: (i) independent of the system-environment coupling, (ii) dictated by the dynamics of the system, and (iii) dominated by the largest Lyapunov expon

S. Kalyana Rama

In the sigma model approach, the $β$-function equations for non critical strings contain a term which acts like a tree level cosmological constant, $Λ$. We analyse the static, spherically symmetric solutions to these equations in $d = 4$ space time and show that the curvature scalar seen by the strings is singular if $Λ\ne 0$. This singularity is naked. Requ

Keith R. Dienes

We investigate the generic distribution of bosonic and fermionic states at all mass levels in non-supersymmetric string theories, and find that a hidden ``misaligned supersymmetry&#39;&#39; must always appear in the string spectrum. We show that this misaligned supersymmetry is ultimately responsible for the finiteness of string amplitudes in the absence of

K. Funakubo, A. Kakuto, S. Otsuki, K. Takenaga

A general prescription to solve the Dirac equation in the presence of CP-violating electroweak bubble wall is presented. The profile of the bubble wall is not specified except that the wall height is $m_0$ and zero deep in the broken- and the symmetric-phase regions, respectively, where $m_0$ is a fermion mass given by the Higgs-vacuum-expectation value and

A. Stadler, B. F. Gibson

Motivated by the $Σ$-hypernuclear states reported in ($K^-,π^{\pm}$) experiments, we have explored the possibility that there exists a particle-stable $Σ^- nn$ bound state. For the Jülich à hyperon-nucleon, realistic-force model, our calculations yield little reason to expect a positive-parity bound state in either the $J = \frac{1}{2}$ or the $J = \frac{3}{

Ekkard Schnedermann

New high statistics data from the second generation of ultrarelativistic heavy-ion experiments open up new possibilities in terms of data analysis. To fully utilize the potential we propose to analyze the $m_\perp$-spectra of hadrons using the inverse Laplace transform. The problems with its inherent ill-definedness can be overcome and several applications i