August 1995 arXiv papers — page 9

Uwe Mueller

An algorithm is described to convert Lorentz and gauge invariant expressions in non--Abelian gauge theories with matter into a standard form, consisting of a linear combination of basis invariants. This algorithm is needed for computer calculations of effective actions. The defining properties of the basis invariants are reported. The number of basis invaria

I. P. Ennes, J. M. Isidro, A. V. Ramallo

The topological field theories associated with affine Lie superalgebras are constructed. Their BRST symmetry is characterised by a Kazama algebra containing spin 1, 2 and 3 operators and closes linearly. Under this symmetry all operators are grouped into BRST doublets. The relation between the models constructed and non-critical string theories is explored.

Jun-ichirou Koga, Kei-ichi Maeda

We study both spherically symmetric and rotating black holes with dilaton coupling and discuss the evaporation of these black holes via Hawking's quantum radiation and their fates. We find that the dilaton coupling constant $α$ drastically affects the emission rates, and therefore the fates of the black holes. When the charge is conserved, the emission r

Yu Cai, Han-Ying Guo, Dao-Neng Gao

There exist certain intrinsic relations between the ultraviolet divergent graphs and the convergent ones at the same loop order in renormalizable quantum field theories. Whereupon we may establish a new method, the intrinsic regularization method, to regularize those divergent graphs. In this paper, we apply this method to QCD at the one loop order. It turns

W. S. l'Yi

Quantum canonical transformations of the second kind and the non-Hermitian realizations of the basic canonical commutation relations are investigated with a special interest in the generalization of the conventional ladder operators. The operator ordering problem is shown to be resolved when the non-Hermitian realizations for the canonical variables which ca

Masayuki Noguchi, Sung-Kil Yang

The Landau-Ginzburg formulation of two-dimensional topological sigma models on the target space with positive first Chern class is considered. The effective Landau-Ginzburg superpotential takes the form of logarithmic type which is characteristic of supersymmetric theories with the mass gap. The equations of motion yield the defining relations of the quantum

O. J. P. Eboli, M. B. Magro, P. G. Mercadante

We study the constraints on the anomalous coupling $g^Z_5$ that can be obtained from the analysis of the reaction $γγ\rightarrow W^+ W^- Z$ at future linear $e^+e^-$ colliders. We find out that a $0.5$ ($1$) TeV $e^+e^-$ collider operating in the $γγ$ mode can probe values of $g_5^Z$ of the order of $0.15$ ($4.5 \times 10^{-2}$) for an integrated luminosity

Rathin Adhikari, Biswarup Mukhopadhyaya

If a light gaugino sector exists in the supersymmetric standard model then the mass of lightest neutralino may be of the order of 1 GeV or less. As a consequence of neutral flavor violation in supersymmetric theories $B_s$-meson may decay into a pair of lightest neutralinos in such a case. It is found that the parameter space for such light neutralinos can b

S. Veseli, M. G. Olsson

We reexamine contributions of higher $K$-resonances to the radiative rare decays $b\rar sγ$ in the limit where both $b$- and $s$-quark are considered heavy. Using the non-relativistic quark model, and the form factor definitions consistent with the HQET covariant trace formalism, we find significant disagreement with previous work which also used heavy quark

Manuel Drees, Atsushi Yamada

We point out that in a large class of superstring--inspired $E(6)$ models, either an e+e- collider operating at a center--of--mass energy $\rs= 1.5$ TeV or higher must detect the pair production of charged or neutral exotic leptons, or an e+e- collider with $\rs \geq 300$ GeV must discover at least one light neutral Higgs boson with invisible branching ratio

J. Lopez, D. Nanopoulos

We revisit the Missing Doublet Model (MDM) as a means to address the apparent difficulties of the minimal $SU(5)$ supergravity model in dealing with the doublet-triplet splitting problem, the prediction of $α_3(M_Z)$, and the proton lifetime. We revamp the original MDM by extending its observable sector to include fields and interactions that naturally suppr

Jonathan L. Rosner

The width of a recently discovered excited charmed-strange baryon, a candidate for a state $Ξ_c^*$ with spin 3/2, is calculated. In the absence of configuration mixing between the ground-state (spin-1/2) charmed-strange baryon $Ξ_c^{(a)}$ and the spin-1/2 state $Ξ_c^{(s)}$ lying about 95 MeV above it, one finds $\tilde Γ(Ξ^*_c \to Ξ_c^{(a)} π) = (3/4) \tilde

Jeffrey D. Richman, Patricia R. Burchat

We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements $V_{cb

V. Berezinsky, A. Bottino, J. Ellis, N. Fornengo

Neutralino dark matter is studied in the context of a supergravity scheme where the scalar mass terms are not constrained by universality conditions at the grand unification scale. We analyse in detail the consequences of the relaxation of this universality assumption on the supersymmetric parameter space, on the neutralino relic abundance and on the event r

E. V. Balandina, A. F. Krutov, V. E. Troitsky

The elastic charge form factors of the charged $π$ and $K$ mesons are calculated in modified impulse approximation using instant form of relativistic Hamiltonian dynamics. Our approach gives pion and kaon electromagnetic form factors in the large range of momentum transfer. The results are in good agreement with the available data. Relativistic effects are l

Tamás G. Kovács, E. T. Tomboulis

We study the correlation function of the 2d SU(2) principal chiral model on the lattice. By rewriting the model in terms of Z(2) degrees of freedom coupled to SO(3) vortices we show that the vortices play a crucial role in disordering the correlations at low temperature. Using a series of exact transformations we prove that, if satisfied, certain inequalitie

Urs M. Heller

We present further evidence for the bulk nature of the phase transition line in the fundamental--adjoint action plane of SU(3) lattice gauge theory. Computing the string tension and some glueball masses along the thermal phase transition line of finite temperature systems with $N_t=4$, which was found to join onto the bulk transition line at its endpoint, we

Eric Poisson

This article is intended to provide a pedagogical account of issues related to, and recent work on, gravitational waves from coalescing compact binaries (composed of neutron stars and/or black holes). These waves are the most promising for kilometer-size interferometric detectors such as LIGO and VIRGO. Topics discussed include: interferometric detectors and

Barbara Drossel, Mehran Kardar

Using a combination of analytic arguments and numerical simulations, we determine lower and upper bounds for the energy barriers to the motion of a defect line in a random potential at low temperatures. We study the cases of magnetic flux lines in high-$T_{c}$ superconductors in 2 and 3 dimensions, and of domain walls in 2 dimensional random-field Ising mode

M. Haataja, J. A. Nieminen, T. Ala-Nissila

In this work we address a novel feature of spreading dynamics of tiny liquid droplets on solid surfaces, namely the case where the ends of the molecules feel different interactions to the surface. We consider a simple model of dimers and short chain--like molecules which cannot form chemical bonds with the surface. We study the spreading dynamics by Molecula

Christian Münkel, Dieter W. Heermann

The phase structure of self-avoiding polymerized membranes is studied by extensive Hybrid Monte Carlo simulations. Several folding transitions from the flat to a collapsed state are found. Using a suitable order parameter and finite size scaling theory, these transitions are shown to be of {\em first order}. The phase diagram in the temperature-field plane i

Dmitrii L. Maslov, Michael Stone, Paul M. Goldbart, Daniel Loss

A theory describing a one-dimensional Luttinger liquid in contact with superconductor is developed. Boundary conditions for the fermion fields describing Andreev reflection at the contacts are derived and used to construct a bosonic representation of the fermions. The Josephson current through a superconductor/Luttinger liquid/superconductor junction is cons

Ramesh Narayan

Most accreting black holes emit a substantial fraction of their luminosity in hard X-rays/soft $γ$-rays of up to $\sim{\rm few}\times100$ keV. The observations suggest that the radiating gas is very hot, $T>10^9$ K, and optically thin. Theoretical attempts to explain the observations are reviewed and unresolved issues are highlighted.

F. Prada, A. Manchado, B. Canzian, R. F. Peletier

Near-infrared H_2 1-0 S(1) and Br_gamma velocity curves along the major axis of NGC 253 have revealed a central velocity gradient that is seven times steeper than that shown by the optical velocity curve. This is interpreted as an optical depth effect due to dust. Approximately 35 mag of visual extinction in the center is required to match the SW side of the

Craig J. Copi, David N. Schramm, Michael S. Turner

Systematic uncertainties in the light-element abundances and their evolution make a rigorous statistical assessment difficult. However, using Bayesian methods we show that the following statement is robust: the predicted and measured abundances are consistent with 95\% credibility only if the baryon-to-photon ratio is between $2\times 10^{-10}$ and $6.5\time

G. Mathez, L. Van Waerbeke, Y. Mellier, H. Bonnet

This paper describes the simulation of realistic Monte-Carlo extragalactic catalogues, aimed at comparing the behaviour of cosmological tests versus input parameters. QSO catalogues are built on a Luminosity Function derived from data through suitable computation of individual maximum volumes in complete (but magnitude- and redshift-limited) samples requirin

L. Van Waerbeke, G. Mathez, Y. Mellier, H. Bonnet

A new cosmological test is derived, based on the distribution of individual V/Vmax in a complete redshift-limited sample of distant objects. The fundamental assumption is that, in any bin of absolute luminosity, individual V/Vmax are required to be uniformly spread over the [0,1] range. This condition of uniformity allows a likelihood function to be computed

Julio F. Navarro, Carlos S. Frenk, Simon D. M. White

We use N-body simulations to investigate the structure of dark halos in the standard Cold Dark Matter cosmogony. Halos are excised from simulations of cosmologically representative regions and are resimulated individually at high resolution. We study objects with masses ranging from those of dwarf galaxy halos to those of rich galaxy clusters. The sphericall

Emilio Molinari

We present here the results about the determination of the Luminosity Function (LF) for elliptical galaxies in the core of fairly rich clusters as a function of redshift and try to compare with the known LF of close, better studied clusters of galaxies. We then outline the first use of a new method of selecting member elliptical galaxies using an unsupervise

G. P. Korchemsky

The Regge behaviour of the scattering amplitudes in perturbative QCD is governed in the generalized leading logarithmic approximation by the contribution of the color--singlet compound states of Reggeized gluons. The interaction between Reggeons is described by the effective hamiltonian, which in the multi--color limit turns out to be identical to the hamilt

M. Tanimoto

In the minimal supersymmetric standard model, we have studied the evolution of the neutrino flavor mixing by using the renormalization group equation(RGE) with the Georgi-Jarlskog texture for the Yukawa coupling matrices.For the large Yukawa coupling of the charged lepton, i.e.,$\tan\b \gg 1$, the neutrino flavor mixing increases significantly with running d

M. Miyama, S. Kumano

We investigate numerical solution of $Q^2$ evolution equations for structure functions in the nucleon and in nuclei. (Dokshitzer-Gribov-Lipatov-)Altarelli-Parisi and Mueller-Qiu evolution equations are solved in a brute-force method. Spin-independent flavor-nonsinglet and singlet equations with next-to-leading-order $α_s$ corrections are studied. Dividing th

Helmut Kroger, Norbert Scheu

We compute structure functions in the Hamiltonian formalism on a momentum lattice using a physically motivated regularisation that links the maximal parton number to the lattice size. We show for the $ϕ^4 _{3+1}$ theory that our method allows to describe continuum physics. The critical line and the renormalised mass spectrum close to the critical line are co

A. Virosztek, K. Maki

We study theoretically the sound propagation in charge- and spin-density waves in the hydrodynamic regime. First, making use of the method of comoving frame, we construct the stress tensor appropriate for quasi-one dimensional systems within tight-binding approximation. Taking into account the screening effect of the long-range Coulomb interaction, we find t

A. Furusaki, K. A. Matveev

We develop a theory of the conductance of a quantum dot connected to two leads by single-mode quantum point contacts. If the contacts are in the regime of perfect transmission, the conductance shows no Coulomb blockade oscillations as a function of the gate voltage. In the presence of small reflection in both contacts, the conductance develops small Coulomb

Alexey Vikhlinin

We calculate the contribution to the cosmic x-ray background (CXB) of a population of power law spectrum sources with spectral indices distributed over a broad range of values. The composite spectrum of this source population is significantly harder than that given by the power law having the average value of spectral indices. Starting from spectral distribu

Joerg Jahnel

For line bundles on arithmetic varieties we construct height functions using arithmetic intersection theory. In the case of an arithmetic surface, generically of genus g, for line bundles of degree g equivalence is shown to the height on the Jacobian defined by the Theta divisor.

H. F. Chau, H. -K. Lo

We consider a probabilistic quantum implementation of a variable of the Pocklington-Lehmer $N-1$ primality test using Shor's algorithm. O($\log^3 N \log\log N \log\log\log N$) elementary q-bit operations are required to determine the primality of a number $N$, making it (asymptotically) the fastest known primality test. Thus, the potential power of quant

J. C. Peng, D. M. Jansen, Y. C. Chen

The sensitivity of proton-induced $J/ψ$ and $Υ$ production to the possible $\bar u/\bar d$ asymmetry in the nucleon is studied. The ratio of the quarkonium production cross sections at large $x_F$ on hydrogen over deuterium targets, $σ(p+p) / σ(p+d)$, is shown to be sensitive to this asymmetry. Predictions of various theoretical models for this ratio are pre

J. C. Peng, D. M. Jansen

The sensitivity of $W$ and $Z$ production at RHIC to the possible $\bar u/\bar d$ asymmetry in the proton is studied. The ratios of the $W^+$ over $W^-$ production cross sections in $p + p$ collision, as well as the ratios of the $W^+$ and $Z$ production cross sections for $p + p$ over $p + d$ collisions, are shown to be sensitive to this asymmetry. Predicti

A. A. Koulakov, M. M. Fogler, B. I. Shklovskii

We study the ground state of a clean two-dimensional electron liquid in a weak magnetic field where $N \gg 1$ lower Landau levels are completely filled and the upper level is partially filled. It is shown that the electrons at the upper Landau level form domains with filling factor equal to one and zero. The domains alternate with a spatial period of order o

Debrupa Chakraverty, Anirban Kundu

The scalar sector of the Standard Model is extended to include an arbitrary assortment of scalars. In the case where this assignment does not preserve $ρ=1$ at the tree-level, the departure from unity itself puts the most stringent constraint on the scalar sector, and where $ρ_{tree}=1$ is maintained, useful bounds on the parameter space of the charged Higgs

Ettore Aldrovandi

We point out that the Miura transformation is related to a holomorphic foliation in a relative flag manifold over a Riemann Surface. Certain differential operators corresponding to a free field description of $W$--algebras are thus interpreted as partial connections associated to the foliation.

George Lavrelashvili

This is a brief review of the main properties of sphalerons in various theories with a Yang--Mills field. Talk given at the Heat Kernel Techniques and Quantum Gravity, Winnipeg, Canada, August 2-6, 1994.

Aneesh V. Manohar

These lectures introduce some of the basic notions of effective field theories, as used in particle physics. The topics discussed are the $ΔS=1$ and $ΔS =2$ weak interactions, and chiral perturbation theory as applied to mesons, baryons, and hadrons containing heavy quarks.

S. Mignemi

We investigate two-dimensional higher derivative gravitational theories in a Riemann-Cartan framework and obtain the most general static black hole solutions in conformal coordinates. We also consider the hamiltonian formulation of the theory and discuss its symmetries, showing they are implemented by a non-linear generalizations of the 2-dimensional Poincar

George E. A. Matsas

We develop an alternative derivation of Unruh and Wald's seminal result that the absorption of a Rindler particle by a detector as described by uniformly accelerated observers corresponds to the emission of a Minkowski particle as described by inertial observers. Actually, we present it in an inverted version, namely, that the emission of a Minkowski par

R. Balasubramanian, B. S. Sathyaprakash, S. V. Dhurandhar

The paper deals with issues pertaining the detection of gravitational waves from coalescing binaries. We introduce the application of differential geometry to the problem of optimal detection of the `chirp signal'. We have also carried out extensive Monte Carlo simulations to understand the errors in the estimation of parameters of the binary system. We

C. G. Boyd, B. Grinstein, R. Lebed

We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function to B -> D* l nu form factors, and extract |V_cb|=0.0355^{+0.0029}_{-0.0025} from experimental data with a least squares f

G. Fiore, G. Modanese

We derive the kinematical constraints which characterize the decay of any massless particle in flat spacetime. We show that in perturbation theory the decay probabilities of photons and Yang-Mills bosons vanish to all orders; the decay probability of the graviton vanishes to one-loop order for graviton loops and to all orders for matter loops. A general powe

Yolanda Lozano

We show that S-duality in four dimensional non-supersymmetric abelian gauge theories can be formulated as a canonical transformation in the phase space of the theory. This transformation is the usual interchange between electric and magnetic degrees of freedom. It is shown that in phase space the modular anomaly emerges as the result of integrating out the m

Tim R. Morris

We show how the exact renormalization group for the effective action with a sharp momentum cutoff, may be organised by expanding one-particle irreducible parts in terms of homogeneous functions of momenta of integer degree (Taylor expansions not being possible). A systematic series of approximations -- the $O(p^M)$ approximations -- result from discarding fr

Bas V. de Bakker

This is my PhD thesis on four-dimensional simplicial quantum gravity using the dynamical triangulation model. Most of the results we have published in separate papers are collected here for your convenience. Some new results have been added as well. Besides these results this thesis also contains an introduction to simplicial quantum gravity and a detailed d

F. Guinea, Yu. Pogorelov

In superconductors where the coherence length is comparable to the Fermi wavelength, the vortex viscosity depends on the velocity of the vortex, leading to non linear equations of motion. The trajectories of vortices driven by a. c. fields show a variety of behaviors as function of frequency. Finite pertubations give rise to very long lived transients. The r

Hitoshi Konno

Spin generalization of the relativistic Calogero-Sutherland model is constructed by using the affine Hecke algebra and shown to possess the quantum affine symmetry $\uqglt$. The spin-less model is exactly diagonalized by means of the Macdonald symmetric polynomials. The dynamical density-density correlation function as well as one-particle Green function are

Heinz J. Rothe

We show that the additional contribution to the Michael lattice energy sum rule for the static quark-antiquark potential, pointed out recently, can be identified with the contribution to the field energy arising from the trace anomaly of the energy momentum tensor. We also exlicitely exhibit the anomalous contribution to the field energy in the sum rule for

A. J. Buchmann, Georg Wagner, K. Tsushima, Amand Faessler

The narrow peak recently found in various pionic double charge exchange (DCX) cross sections can be explained by the assumption of a universal resonance at 2065 MeV, called d'. We calculate the mass of a six-quark system with J^P=0^-, T=0 quantum numbers employing a cluster model and a shell model basis to diagonalize the nonrelativistic quark model Hami

N. Armesto, C. Pajares, C. A. Salgado, Yu. M. Shabelski

We calculate the A-dependence of charm and beauty production cross sections on nuclear targets taking into account the difference of quark and gluon distributions in free nucleons and in nucleus. At comparatively low energies, if $σ\sim A^α$, the value of $α$ is slightly higher than unity. With the growth of the initial energy the value of $α$ decreases and

Tatsuya Ueno

We reformulate the self-dual Einstein equation as a trio of differential form equations for simple two-forms. Using them, we can quickly show the equivalence of the theory and 2D sigma models valued in an infinite-dimensional group, which was shown by Park and Husain earlier. We also derive other field theories including the 2D Higgs bundle equation. This fo

D. Aronstein, T. Bergfeld, D. Horton, M. Palmer

The key parameters of Cherenkov Correlated Timing (CCT) detectors are discussed. Measurements of radiator geometry, optical properties of radiator and coupling materials, and photon detector timing performance are presented.

H. Kichimi, Y. Sugaya, H. Yamaguchi, Y. Yoshimura

Several prototypes of a Cherenkov Correlated Timing (CCT) Detector have been tested at the KEK-PS test beam line. We describe the results for Cherenkov light yields and timing characteristics from quartz and acrylic bar prototypes. A Cherenkov angle resolution is found to be 15 mrad at a propagation distance of 100 cm with a 2 cm thick quartz bar prototype.

J. J. Halliwell, T. Yu

Hu, Paz and Zhang [ B.L. Hu, J.P. Paz and Y. Zhang, Phys. Rev. D {\bf 45} (1992) 2843] have derived an exact master equation for quantum Brownian motion in a general environment via path integral techniques. Their master equation provides a very useful tool to study the decoherence of a quantum system due to the interaction with its environment. In this pape

Yunping Jiang

We construct a subset of the Mandelbrot set which is dense on the boundary of the Mandelbrot set and which consists of only infinitely renormalizable points such that the Mandelbrot set is locally connected at every point of this subset. We prove the local connectivity by finding bases of connected neighborhoods directly.

E. V. Flynn, Bjorn Poonen, Edward F. Schaefer

It has been conjectured that for $N$ sufficiently large, there are no quadratic polynomials in $\bold Q[z]$ with rational periodic points of period $N$. Morton proved there were none with $N=4$, by showing that the genus~$2$ algebraic curve that classifies periodic points of period~4 is birational to $X_1(16)$, whose rational points had been previously compu

Vladimir O. Soloviev

In this report it is proposed to generalize the definition of Poisson brackets in order to treat spatial integrals of divergences as Hamiltonians which generate a kind of Hamiltonian equations on the boundary. Nonlinear Schrodinger equation is used as an illustrative example.

Asim Gangopadhyaya, Avinash Khare, Uday P. Sukhatme

We describe three different methods for generating quasi-exactly solvable potentials, for which a finite number of eigenstates are analytically known. The three methods are respectively based on (i) a polynomial ansatz for wave functions; (ii) point canonical transformations; (iii) supersymmetric quantum mechanics. The methods are rather general and give con

Koos de Vos, Peter van Driel

The main result in this paper is the character formula for arbitrary irreducible highest weight modules of W algebras. The key ingredient is the functor provided by quantum Hamiltonian reduction, that constructs the W algebras from affine Kac-Moody algebras and in a similar fashion W modules from KM modules. Assuming certain properties of this functor, the W

Suemi Rodríguez-Romo

An Introduction to Hopf algebras as a tool for the regularization of relavent quantities in quantum field theory is given. We deform algebraic spaces by introducing q as a regulator of a non-commutative and non-cocommutative Hopf algebra. Relevant quantities are finite provided q\neq 1 and diverge in the limit q\rightarrow 1. We discuss q-regularization on d

R. C. Brower, M. Campostrini, K. Orginos, P. Rossi

The large-N saddle-point equations for the principal chiral models defined on a d-1 dimensional simplex are derived from the external field problem for unitary integrals. The saddle point equation are studied analytically and numerically in many relevant instances, including d=4 and $d\rightarrow\infty$, with special attention to the critical domain, which i

B. A. Kniehl, M. Steinhauser

We evaluate the next-to-leading-order QCD corrections of O(alpha_s^2 G_F M_t^2) to the Standard-Model l^+l^-H, ZZH, and W^+W^-H couplings in the heavy-top- quark limit. Exploiting these results together with knowledge of Delta rho to the same order, we analyze a variety of production and decay processes of low- mass Higgs bosons at e^+e^- colliders. Specific

A. Yu. Umnikov, F. C. Khanna

The problem of calculating of the mass spectrum of the two-body Bethe-Salpeter equation is studied with no reduction to the three-dimensional ("quasipotential") equation. The method to find the ground state and excited states for a channel with any quantum numbers is presented. The problem of the confining interaction for the Bethe-Salpeter equation

X. Artru, J. Czyzewski, H. Yabuki

We calculated the single spin asymmetry in the inclusive pion production in the fragmentation region of transversely polarized proton-proton collisions. We generated the asymmetry at the level of fragmentation function (Collins effect) by the Lund coloured string mechanism. We compared our results to the presently available experimental data. We obtained a q

Michel Fontannaz

I discuss the parton distributions in the photon and the constraints coming from the jet production in photoproduction and in photon-photon collisions.

S. Ambrosanio, B. Mele

A complete phenomenological study of the next-to-lightest neutralino decays is performed in the MSSM. The widths and branching ratios for all the possible decay channels (including the radiative decay X0(2) --> X0(1) gamma and the decay into a light Higgs X0(2) --> X0(1) h0) are studied in detail as functions of all the SuSy parameters of the model. Particul

B. C. Allanach, S. F. King

We discuss the fermion mass problem in SUSY GUTs, including such ideas as texture zeroes, and Georgi-Jarlskog textures. We focus on a specific supersymmetric model based on the gauge group $SU(4)\otimes SU(2)_L \otimes SU(2)_R$. In this model the gauge group is broken to that of the standard model at $10^{16}$ GeV, and supersymmetry is broken at low-energy.

Denis Perrer-Gallix

Complete Feynman diagram automatic computation systems are now coming of age after many years of development. They are made available to the high energy physics community through user-friendly interfaces. Theorists and experimentalists can benefit from these powerful packages for speeding up time consuming calculations and for preparing event generators. The

W. Cassing, W. Ehehalt, C. M. Ko

We present a nonperturbative dynamical study of $e^+e^-$ production in proton- nucleus and nucleus-nucleus collisions at SPS energies on the basis of a covariant transport approach. For p + A reactions the dilepton yield for invariant masses m $\leq $ 1.2 GeV is found to be dominated by the decays of the $η, ρ, ω$ and $Φ$ mesons in line with the findings of

T. Morii, S. Tanaka, T. Yamanishi

QCD suggests that gluons in the nucleon play an important role in {\it so-called} ``the proton spin problem''. In this talk, the behavior of the polarized gluon distribution in the nucleon is discussed by using the positivity condition of distribution functions together with the unpolarized and polarized experimental data.

Frank Cuypers, Clemens A. Heusch

We point out that both the specific lepton number content and the high energies potentially attainable with muon-muon colliders make it advisable to consider the technical feasibility of including an option of like-sign incoming beams in the studies towards a proposal to build a muon-muon collider with center-of-mass energies in the TeV region. This capabili

Jerrold Franklin

The spin dependent structure functions, g$_{1p}$ of the proton and g$_{1n}$ of the neutron, calculated in the nucleon rest frame using a relativistic quark model wave function, are compared with recent experiments.

Benjamin Grinstein

Introductory lectures (delivered at the VI Mexican School of Particles and Fields) on heavy quarks and heavy quark effective field theory. Applications to inclusive semileptonic decays and to interactions with light mesons are covered in detail.

CLEO Collaboration, P. Avery et al

Using data recorded by the CLEO-II detector at CESR, we report the first observation of a narrow state decaying into $Ξ_c^+π^-$. The state has mass difference $M(Ξ_c^+π^-)-M(Ξ_c^+)$ of $178.2\pm0.5\pm1.0$ $\rm{MeV/c^2}$, and a width of $<5.5$ $\rm{MeV/c^2}$ (90\% confidence level limit). The most likely explanation of this new state is that it is the $J=\32$

CLEO Collaboration, G. Brandenburg et al

Using the CLEO~II detector we measure ${\cal B}(D_s^+\to ηe^+ν)/{\cal B}(D_s^+\to ϕe^+ν) =1.24\pm0.12\pm0.15$, ${\cal B}(D_s^+\to η&#39; e^+ν)/{\cal B}(D_s^+\to ϕe^+ν) =0.43\pm0.11\pm0.07$ and ${\cal B}(D_s^+\to η&#39; e^+ν)/{\cal B}(D_s^+\to ηe^+ν) =0.35\pm0.09\pm0.07$. We find the vector to pseudoscalar ratio, ${\cal B}(D_s^+\to ϕe^+ν)/{\cal B}(D_s^+\to (η

Giampiero Esposito, Gennaro Miele, Luigi Rosa, Pietro Santorelli

Electrodynamics for self-interacting scalar fields in spatially flat Friedmann-Robertson-Walker space-times is studied. The corresponding one-loop field equation for the expectation value of the complex scalar field in the conformal vacuum is derived. For exponentially expanding universes, the equations for the Bogoliubov coefficients describing the coupling

A. Mikovic

We study a manifestly unitary formulation of 2d dilaton quantum gravity based on the reduced phase space quantization. The spacetime metric can be expanded in a formal power series of the matter energy-momentum tensor operator. This expansion can be used for calculating the quantum corrections to the classical black hole metric by evaluating the expectation

Gregory A. Burnett

Up to a conjecture in Riemannian geometry, we significantly strengthen a recent theorem of Eardley by proving that a compact region in an initial data surface that is collapsing sufficiently fast in comparison to its surface-to-volume ratio must contain a future trapped region. In addition to establishing this stronger result, the geometrical argument used d

Per Kraus

The phenomenon of black hole thermodynamics raises several deep issues which any proper theory of quantum gravity must confront: to what extent does the inclusion of the back-reaction alter the thermal character of the radiation, how can the entropy be understood from a microscopic standpoint, what is the ultimate fate of an evaporating black hole, and is th

A. V. Aminova, D. A. Kalinin

We discuss the quantization of mechanical systems for which the Hamiltonian vector fields of observables form the deformation of $n$-dimensional oscilator algebra. Because of this fact these systems can be considered as &#34;deformations&#34; of the harmonic oscillator. The set of abovementioned mechanical systems are realized at the classical level in the f

F. Tzschichholz, H. J. Herrmann, H. Zanni

We propose a heterogeneous reaction-diffusion model for the hydration and setting of cement. The model is based on diffusional ion transport and on cement specific chemical dissolution/precipitation reactions under spatial heterogeneous solid/liquid conditions. We simulate the spatial and temporal evolution of precipitated micro structures starting from init

Atsushi Yamagata

We study the critical phenomena of the hard-sphere lattice gas on the simple cubic lattice with nearest neighbour exclusion by the Monte Carlo method. We get the critical exponents, $β/ ν$ = 0.313(9) and $γ/ ν$ = 2.37(2), where $β$ is the critical exponent for the staggered density, $γ$ for the staggered compressibility, and $ν$ for the correlation length.

E. Balkovsky, M. Chertkov, I. Kolokolov, V. Lebedev

Advection of a passive scalar $θ$ in $d=2$ by a large-scale velocity field rapidly changing in time is considered. The Gaussian feature of the passive scalar statistics in the convective interval was discovered in \cite{95CFKLa}. Here we examine deviations from the Gaussianity: we obtain analytically the simultaneous fourth-order correlation function of $θ$.

Christopher Adler, Bruce M. Boghosian, Eirik G. Flekkøy, Norman Margolus

We demonstrate how three-dimensional fluid flow simulations can be carried out on the Cellular Automata Machine 8 (CAM-8), a special-purpose computer for cellular-automata computations. The principal algorithmic innovation is the use of a lattice-gas model with a 16-bit collision operator that is specially adapted to the machine architecture. It is shown how

Diego M. Molteni, H. Sponholz, Sandip K. Chakrabarti

We extend our previous numerical simulation of accretion disks with shock waves when cooling effects are also included. We consider bremsstrahlung and other power law processes: $Λ\propto T^α ρ^2$ to mimic cooling in our simulation. We employ {\it Smoothed Particle Hydrodynamics} technique as in the past. We observe that for a given angular momentum of the f

B. Link, R. I. Epstein

We examine the thermal and dynamical response of a neutron star to a sudden perturbation of the inner crust temperature. During the star&#39;s evolution, starquakes and other processes may deposit $\gap 10^{42}$ ergs, causing significant internal heating and increased frictional coupling between the crust and the more rapidly rotating neutron superfluid the

F. Halzen

An ever-increasing body of evidence suggests that weakly interacting massive particles (WIMPs) constitute the bulk of the matter in the Universe. We illustrate how experimental data, dimensional analysis and Standard Model particle physics are sufficient to evaluate and compare the potential of detectors searching for such particles either directly (e.g.\ by

Petri Mahonen, Pasi Hakala

We report progress in the development of automatic star/galaxy classifier for processing images generated by large galaxy surveys like APM. Our classification method is based on neural networks using the Kohonen Self-Organizing Map approach. Our method is novel, since it does not need supervised learning, i.e. human factor, in training. The analysis presente

M. G. Akritas, J. Siebert

A new procedure is presented, which allows, based on Kendall&#39;s $τ$, to test for partial correlation in the presence of censored data. Further, a significance level can be assigned to the partial correlation -- a problem which hasn&#39;t been addressed in the past, even for uncensored data. The results of various tests with simulated data are reported. Fi

B. Schupp, J. J. van der Bij

A new solution to the coupled gravitational and scalar field equations for a condensed boson field is found in Newtonian approximation. The solution is axially symmetric, but not spherically symmetric. For N particles the mass of the object is given by $M = Nm - 0.02298 N^3 G_N^2 m^5$, to be compared with $M = Nm - 0.05426 N^3 G_N^2 m^5$ for the spherically

R. Durrer, Z. -H. Zhou

We investigate cosmological structure formation seeded by topological defects which may form during a phase transition in the early universe. First we derive a partially new, local and gauge invariant system of perturbation equations to treat microwave background and dark matter fluctuations induced by topological defects or any other type of seeds. We then

David Eichler, Biman B. Nath

Companion stars exposed to high energy radiation from a primary neutron star or accreting black hole can experience significant spallation of their heavy elements, so that their atmospheres would be extremely rich in lithium, beryllium, and especially boron. In this paper we note that the detection or non-detection of these elements, and their relative abund