December 1996 arXiv papers — page 11

A. C. S. Friaca, D. R. Goncalves, L. C. Jafelice, V. Jatenco-Pereira

One of the major problems concerning cooling flows is the nature of the mechanism powering the emission lines of the optical filaments seen in the inner regions of cooling flows. In this work we investigate the plausibility of Alfvén heating (AH) as a heating/excitation mechanism of optical filaments in cooling flows. We use a time-dependent hydrodynamical c

Michael N. Fanelli, Theodore P. Stecher, the UIT Science Team

During the UIT/Astro Spacelab missions, the Ultraviolet Imaging Telescope obtained spatially resolved far-UV (lambda 1500 A) imagery of ~35 galaxies exhibiting recent massive star formation. The sample includes disk systems, irregular, dwarf, and blue compact galaxies. The objects span an observed FUV luminosity range from -17 to -22 magnitudes. We estimate

Laura Maraschi, Giovanni Fossati

Average Spectral Energy Distributions (SED) for different subgroups of blazars are derived from available homogeneous (but small) data sets, including the gamma-ray band. Comparing Flat Spectrum Radio Quasars (FSRQ) with BL Lacs extracted from radio (RBL) or X-ray surveys (XBL) remarkable differences and similarities are apparent: i) in all cases the overall

G. Fossati, A. Celotti, G. Ghisellini, L. Maraschi

We discuss alternative interpretations of the differences in the Spectral Energy Distributions (SEDs) of BL Lacs found in complete Radio or X--ray surveys. In order to explain the different properties of radio and X-ray selected within the assumption of a single population we propose a new approach The model is based on the idea that the BL Lacs constitute a

Francesco Haardt

The current status of understanding of the X-ray emission from Seyfert galaxies involves thermal Comptonization of soft photons by mildrelativistic electrons and positrons. I review observational and theoretical arguments supporting such a view, discussing current models proposed for the structure of the innermost part of the accretion flow: extended coronae

Gabriele Ghisellini, Francesco Haardt, Roland Svensson

There are difficulties in understanding what keeps the plasma thermalized in compact sources, especially during rapid variations of the emitted flux. Particle-particle collisions are too inefficient in hot rarefied plasmas, and a faster process is called for. Synchrotron absorption is such a process. We show that relativistic electrons can thermalize in a fe

R. P. Fender, P. Roche, G. G. Pooley, D. Chakrabarty

We present results from a deep search for radio emission from the X-ray pulsar systems GX 1+4, GS 0834-430 and 4U 0115+63 which have variously been suggested to possess radio jets and to be good candidates for propellor ejection mechanisms. None of these sources is detected at their optical positions, to 3 sigma limits of a few hundred micro-Jy. This places

A. R. Petrosian, J. Boulesteix, G. Comte, D. Kunth

We present high spatial resolution observations of the blue compact dwarf galaxy IZW18 performed in the Halpha line with a scanning Fabry-Perot interferometer at the CFH telescope. Morphological structure of the galaxy in Halpha and in the red continuum is investigated. We also analyse the velocity field of the ionized gas. Besides the two compact HII compon

Vladimir V. Usov

The energy source of a pulsar's non-thermal emission is the rotational energy loss of the neutron star. The rotational energy of the neutron star is transformed into the pulsar radiation by a long sequence of processes. The processes of this sequence are discussed.

E. J. Wampler

If the unexpectedly high frequency of quasar pairs with very different component redshifts is due to the lensing of a population of background quasars by the foreground quasar, typical lens masses must be $\sim10^{12}M_{\sun}$ and the sum of all such quasar lenses would have to contain $\sim0.005$ times the closure density of the Universe. It then seems plau

Christof Zalka

I make a rough estimate of the accuracy threshold for fault tolerant quantum computing with concatenated codes. First I consider only gate errors and use the depolarizing channel error model. I will follow P.Shor (quant-ph/9505011) for fault tolerant error correction (FTEC) and the fault tolerant implementation of elementary operations on states encoded by t

Agustin Nieto

Recent developments of perturbation theory at finite temperature based on effective field theory methods are reviewed. These methods allow the contributions from the different scales to be separated and the perturbative series to be reorganized. The construction of the effective field theory is shown in detail for phi^4 theory and QCD. It is applied to the e

G. McCartor, D. G. Robertson, S. S. Pinsky

We discuss the problem of vacuum structure in light-front field theory in the context of (1+1)-dimensional gauge theories. We begin by reviewing the known light-front solution of the Schwinger model, highlighting the issues that are relevant for reproducing the $θ$-structure of the vacuum. The most important of these are the need to introduce degrees of free

Fyodor V. Tkachov

The controversy concerning the phenomenon of breakdown of dimensional regularization in the problems involving asymptotic expansions of Feynman diagrams in non-Euclidean regimes is discussed with some pertinent bibliographic comments.

Sandu Popescu, Lucien Hardy, Marek Zukowski

A certain class of parametric down-conversion Bell type experiments has the following features. In the idealized perfect situation it is in only 50% of cases that each observer receives a photon; in the other 50% of cases one observer receives both photons of a pair while the other observer receives none. The standard approach is to discard the events of the

Ara N. Ioannisian, Georg G. Raffelt

We calculate the Cherenkov process nu -> nu+photon in the presence of a homogeneous magnetic field. The neutrinos are taken to be massless with only standard-model couplings. The magnetic field fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation such that the Cherenkov condition is fulfill

A. V. Razumov, M. V. Saveliev

A detailed consideration of the maximally nonabelian Toda systems based on the classical semisimple Lie groups is given. The explicit expressions for the general solution of the corresponding equations are obtained.

Doron Cohen

The main goal of the present paper is to convince that it is feasible to construct a `periodic orbit theory' of localization by extending the idea of classical action correlations. This possibility had been questioned by many researchers in the field of `Quantum Chaos'. Starting from the semiclassical trace formula, we formulate a quantal-classical d

M. V. Medvedev, P. H. Diamond

A simple model collisionless, dissipative, compressible MHD (Alfvenic) turbulence in a magnetized system is investigated. In contrast to more familiar paradigms of turbulence, dissipation arises from Landau damping, enters via nonlinearity, and is distributed over all scales. The theory predicts that two different regimes or phases of turbulence are possible

M. V. Medvedev

A new class of identical particles which may exhibit both Bose and Fermi statistics with respective probabilities $p_b$ and $p_f$ is introduced. Such an uncertainity may be either an intrinsic property of a particle or can be viewed as an ``experimental uncertainity''. Statistical equivalence of such particles and particles obeying parastatistics of

A. V. Razumov, M. V. Saveliev

We discuss a Lie algebraic and differential geometry construction of solutions to some multidimensional nonlinear integrable systems describing diagonal metrics on Riemannian manifolds, in particular those of zero and constant curvature. Here some special solutions to the Lamé and Bourlet type equations, determining by n arbitrary functions of one variable a

A. Kempf, G. Mangano

Studies in string theory and quantum gravity suggest the existence of a finite lower limit $Δx_0$ to the possible resolution of distances, at the latest on the scale of the Planck length of $10^{-35}m$. Within the framework of the euclidean path integral we explicitly show ultraviolet regularisation in field theory through this short distance structure. Both

Achim Kempf

The possibility of the existence of small correction terms to the canonical commutation relations and the uncertainty relations has recently found renewed interest. In particular, such correction terms could induce finite lower bounds $Δx_0, Δp_0$ to the resolution of distances and/or momenta. I review a general framework for the path integral formulation of

Ori J. Ganor

We discuss the dependence of superpotential terms in 4D F-theory on moduli parameters. Two cases are studied: the dependence on world-filling 3-brane positions and the dependence on 2-form VEVs. In the first case there is a zero when the 3-brane hits the divisor responsible for the superpotential. In the second case, which has been extensively discussed by W

A. Widom, Y. N. Srivastava

Traditional analysis of $g=2(1+κ)$ experiments for charged leptons use a classical spin vector picture. For muons, we here employ a more exact Dirac quantum four component spinor theory. Survival probabilities (including wave packet effects) are computed. These oscillate with the frequency $Ω=(κeB/Mc)$ as has been assumed in previous muon $(g-2)$ experimenta

I. A. Shushpanov

Corrections due to gluon condensate to electromagnetic form factors of the transition $π+γ^* \to A_1$ are calculated by standard QCD sum rules technique. The obtained results are compared to the corresponding light-cone QCD sum rules.

G. B. Pivovarov, F. V. Tkachov

The results of part I (hep-ph/9612284) are used to obtain full asymptotic expansions of Feynman diagrams renormalized within the MS-scheme in the regimes when some of the masses and external momenta are large with respect to the others. The large momenta are Euclidean, and the expanded diagrams are regarded as distributions with respect to them. The small ma

W. Buchmüller, O. Philipsen

Non-perturbative effects in the high-temperature phase of the electroweak theory are characterized by a magnetic screening length. Its size influences the range of validity of perturbation theory, and it also determines the critical Higgs boson mass where the first-order phase transition changes to a crossover. We propose a gauge-invariant definition of the

Fyodor V. Tkachov

The problem of asymptotic expansions of Green functions in perturbative QFT is studied for the class of Euclidean asymptotic regimes. Phenomenological applications are analyzed to obtain a meaningful mathematical formulation of the problem. It is shown that the problem reduces to studying asymptotic expansions of products of a class of singular functions in

Wolfhard Janke, Ramon Villanova

We report a fairly detailed finite-size scaling analysis of the first-order phase transition in the three-dimensional 3-state Potts model on cubic lattices with emphasis on recently introduced quantities whose infinite-volume extrapolations are governed `only' by exponentially small terms. In these quantities no asymptotic power series in the inverse vol

Benjamin P. Lee, John Cardy

A recent argument of Oerding shows that our calculation of the quantity Delta, which determines the amplitude of the asymptotic decay of the particle density in d < 2 < 4, was in error. Instead it is simply given by Delta = n_0, the initial density, for uncorrelated initial conditions.

Mina Aganagic, Costin Popescu, John H. Schwarz

The first part of this paper presents actions for Dirichlet p-branes embedded in a flat 10-dimensional space-time. The fields of the (p+1)-dimensional world-volume theories are the 10d space-time coordinates $ X^m$, a pair of Majorana-Weyl spinors $θ_1$ and $θ_2$, and a U(1) gauge field $A_μ$. The N = 2A or 2B super-Poincare group in ten dimensions is realiz

J. J. Palacios, Lerwen Liu, D. Yoshioka

We show how a fine, multiple-peak structure can arise in the off-resonance, zero-bias conductance of Coulomb blockade systems. In order to understand how this effect comes about one must abandon the orthodox, mean-field understanding of the Coulomb blockade phenomenon and consider quantum fluctuations in the occupation of the single-particle electronic level

Victor G. Kac, Ivan T. Todorov

Chiral orbifold models are defined as gauge field theories with a finite gauge group $Γ$. We start with a conformal current algebra A associated with a connected compact Lie group G and a negative definite integral invariant bilinear form on its Lie algebra. Any finite group $Γ$ of inner automorphisms or A (in particular, any finite subgroup of G) gives rise

Dima Mozyrsky, Vladimir Privman, Steven P. Hotaling

We propose to design multispin quantum gates in which the input and output two-state systems (spins) are not necessarily identical. We describe the motivations for such studies and then derive an explicit general two-spin interaction Hamiltonian which accomplishes the quantum XOR gate function for a system of three spins: two input and one output.

Marco D&#39;Attanasio, Massimo Pietroni

The paper ``Transversality of the Gluon Self-Energy at Finite Temperature in General Covariant Gauges&#39;&#39; has been withdrawn.

Arthur Lue, Krishna Rajagopal, Mark Trodden

We examine two semi-analytical methods for estimating the baryon asymmetry of the universe (BAU) generated in scenarios of ``local&#39;&#39; electroweak baryogenesis (in which the requisite baryon number violation and CP violation occur together in space and time). We work with the standard electroweak theory augmented by the addition of a CP violating dimen

D. A. Butts, D. S. Rokhsar

We study the properties of a spin-polarized Fermi gas in a harmonic trap, using the semiclassical (Thomas-Fermi) approximation. Universal forms for the spatial and momentum distributions are calculated, and the results compared with the corresponding properties of a dilute Bose gas.

V. D. Ivashchuk, V. N. Melnikov

Multidimensional gravitational model on the manifold $M = M_0 \times \prod_{i=1}^{n} M_i$, where $M_i$ are Einstein spaces ($i \geq 1$), is considered. The action contains $m = 2^n -1$ dilatonic scalar fields $ϕ^I$ and $m$ (antisymmetric) forms $A^I$. When all fields and scale factors of the metric depend (essentially) on the point of $M_0$ and any $A^I$ is

S. Garcia, G. Guralnik, Z. Guralnik

Quantum field theories and Matrix models have a far richer solution set than is normally considered, due to the many boundary conditions which must be set to specify a solution of the Schwinger-Dyson equations. The complete set of solutions of these equations is obtained by generalizing the path integral to include sums over various inequivalent contours of

Marina Shmakova

We have found the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space. We show that for arbitrary d_{ABC} and black hole charges the entropy-area formula depends on combinations of these charges and parameters d_{ABC}. These combinations are the solutions of the simple system of algebraic equations. We gave a few examples of pa

Kristin Schleich, Donald Witt

Recently an alternate technique for numerical quantum gravity, dynamical triangulation, has been developed. In this method, the geometry is varied by adding and subtracting equilateral simplices from the simplicial complex. This method overcomes certain difficulties associated with the traditional approach in Regge calculus of varying geometry by varying edg

Gen Tatara, Hidetoshi Fukuyama

The resistivity due to a domain wall in ferromagnetic metallic wire is calculated based on the linear response theory. The interaction between conduction electrons and the wall is expressed in terms of a classical gauge field which is introduced by the local gauge transformation in the electron spin space. It is shown that the wall contributes to the decoher

Tota Nakamura, Satoshi Takada

We clarified behavior of the excitation gap in a frustrated S=1/2 quantum spin chain with bond dimerization by using the numerical diagonalization of finite systems and a variational approach. The model interpolates between the independent dimer model and the S=1 spin chain by changing a strength of the dimerization. The energy gap is minimum at the fully-fr

Y. Huang, H. Saleur, C. G. Sammis, D. Sornette

We present a simple model of earthquakes on a pre-existing hierarchical fault network. The system self-organizes on long time scales in a stationary state with a power law Gutenberg-Richter distribution of earthquake sizes. The largest fault carries irregular great earthquakes preceded by precursors developing over long time scales and followed by aftershock

H. J. Haubold

The paper provides results of the Fourier spectrum analysis of the new Ar-37 production rate data of the Homestake solar neutrino experiment and compares them with results for earlier data, revealing the harmonic content in the Ar-37 production in the Homestake experiment.

Mairi Sakellariadou

The origin of the large scale structure in the universe - galaxies, quasars, clusters, voids, sheets - is one of the most important questions in cosmology. One can show that some non-thermal energy density fluctuations must have been present in the early universe. These fluctuations grew by gravitational instability to form the observed structures. There are

Takahiro T. Nakamura, Yasushi Suto

Constraints on cosmological models from strong gravitational lensing statistics are investigated. We pay particular attention to the role of the velocity function in the calculation of the lensing probability. The velocity function derived from the observed galaxy luminosity function, which is used in most previous work, is unable to predict the large separa

W. Bednarek, R. J. Protheroe

We have developed a model for gamma ray emission in jets of active galactic nuclei in which particle acceleration takes place at a shock in the relativistic jet plasma due to a massive star in the central region of the host galaxy moving through the jet. The gamma rays are produced in a pair-Compton cascade in the radiation field of the star initiated by acc

S. Sridhar, J. Touma

We present cuspy, non-axisymmetric, scale-free mass models of discs, whose gravitational potentials are of Stäckel form in parabolic coordinates. A black hole may be added at the centre, without in any way affecting the Stäckel form; the dynamics in these potentials is, of course, fully integrable. The surface density, $Σ_{disc}\propto 1/r^γ$, where $0 <γ< 1

Donu Arapura, Pramathanath Sastry

Let $SU_X(n,L)$ be the moduli space of rank n semistable vector bundles with fixed determinant L on a smooth projective genus g curve X. Let $SU_X^s(n,L)$ denote the open subset parametrizing stable bundles. We show that if g>3 and n > 1, then the mixed Hodge structure on $H^3(SU_X^s(n, L))$ is pure of type ${(1,2),(2,1)}$ and it carries a natural polarizati

Donu Arapura

Let X be a Zariski open subset of a compact Kaehler manifold. In this paper, we study the set $Σ^k(X)$ of one dimensional local systems on X with nonvanishing kth cohomology. We show that under certain conditions (X compact, X has a smooth compactification with trivial first Betti number, or k=1) $Σ^k(X)$ is a union of translates of sets of the form $f^*H^1(

Barbara Badelek

Spin properties of the nucleon are discussed based on the ongoing and planned measurements. Role, method and features of radiative corrections applied in the analyses are presented. Future prospects of the spin physics are reviewed.

Ezra Getzler

The WDVV equation is satisfied by the genus 0 correlation functions of any topological field theory in two dimensions coupled to topological gravity, and may be used to determine the genus 0 (rational) Gromov-Witten invariants of many projective varieties (as was done for projective spaces by Kontsevich). In this paper, we present an equation of a similar un

F. Barbarin, E. Ragoucy, P. Sorba

The property of some finite W algebras to be the commutant of a particular subalgebra of a simple Lie algebra G is used to construct realizations of G. When G=so(4,2), unitary representations of the conformal and Poincare algebras are recognized in this approach, which can be compared to the usual induced representation technique. When G=sp(2,R) or sp(4,R),

R. Graham, D. F. Walls, M. J. Collett, M. Fliesser

We present a quantum theory of low-lying excitations in a trapped Bose condensate with finite particle numbers. We find that even at zero temperature condensate number fluctuations and/or fluctuations of the excitation frequency due to quantum uncertainties of the mode occupation lead to a collapse of the collective modes due to dephasing. Coherent revivals

Arvind, N. Mukunda

We present an operator approach to the description of photon polarization, based on Wigner's concept of elementary relativistic systems. The theory of unitary representations of the Poincare group, and of parity, are exploited to construct spinlike operators acting on the polarization states of a photon at each fixed energy momentum. The nontrivial topologic

M. Nikbakht-Tehrani

We study the Calabi-Yau phase of a certain class of (0,2) models. These are conjectured to be equivalent to exact (0,2) superconformal field theories which have been constructed recently. Using the methods of toric geometry we discuss in a few examples the problem of resolving the singularities of such models and calculate the Euler characteristic of the cor

S. A. Abel

It is shown that in R-parity violating models of supersymmetry, the CP violation observed in the kaon system could arise purely from the R-parity violating scalar interactions (A-terms), with no CP violation in the CKM matrix. The direct CP violating parameter, epsilon&#39;, could be as large or larger than that expected in the Standard Model. CP violation i

Shinji Hirano, Yoichi Kazama

By developing an appropriate path-integral formalism, we compute, in bosonic string theory, the disk amplitude for the scattering of closed string states from a D-particle, in which the collective coordinate of the D-particle is fully quantized. As a consequence, the recoil of the D-particle is naturally taken into account. Our result can be readily factoriz

Edward Farhi, Sam Gutmann

We solve a problem, which while not fitting into the usual paradigm, can be viewed as a quantum computation. Suppose we are given a quantum system described by an N dimensional Hilbert space with a Hamiltonian of the form $E |w >< w|$ where $| w>$ is an unknown (normalized) state. We show how to discover $| w >$ by adding a Hamiltonian (independent of $| w >

John R. Klauder

New measures for the quantization of systems with constraints are discussed and applied to several examples, in particular, examples of alternative but equivalent formulations of given first-class constraints, as well as a comparison of regular and irregular constraints.

V. S. Olkhovsky, A. Agresti

A compact analysis of development and prospects in the study of the tunnelling evolution is given. A new systematization of various approaches to defining tunnelling times in the light of time as a quantum mechanical observable is proposed. The problem of superluminal group velocities, without violations of special relativity, is also taken in account. Then

T. Misu, W. Nazarewicz, S. Aberg

Deformation properties of weakly bound nuclei are discussed in the deformed single-particle model. It is demonstrated that in the limit of a very small binding energy the valence particles in specific orbitals, characterized by a very small projection of single-particle angular momentum onto the symmetry axis of a nucleus, can give rise to the halo structure

Th. Rubehn, W. F. J. Mueller, W. Trautmann

Electromagnetic fission cross sections for the reactions U + (Be, C, Al, Cu, In, Au, U) at E/A = 0.6 and 1.0 GeV are compared to theoretical calculations using recently proposed quantum-mechanical equivalent-photon spectra. In contrast to semi-classical calculations, systematically lower cross sections are obtained that cannot reproduce the experimental resu

Robert Myers

This paper concerns the class of contractible open 3-manifolds which are ``locally finite strong end sums&#39;&#39; of eventually end-irreducible Whitehead manifolds. It is shown that whenever a 3-manifold in this class is a covering space of another 3-manifold the group of covering translations must be a free group. It follows that such a 3-manifold cannot

Tristan Hubsch

String theory has already motivated, suggested, and sometimes well-nigh proved a number of interesting and sometimes unexpected mathematical results, such as mirror symmetry. A careful examination of the behavior of string propagation on (mildly) singular varieties similarly suggests a new type of (co)homology theory. It has the `good behavior&#39; of the we

M. Carvalho, M. W. de Oliveira

We build up a class of N=2 supersymmetric non-linear $σ$-models in an N=1 superspace based on the Atiyah-Ward space-time of (2+2)-signature metric. We also discuss the gauging of isometries of the associated hyper-Kählerian target spaces and present the resulting gauge-covariant supersymmetric action functional.

S. Pinsky

We consider SU(2) Yang-Mills theory in 1+1 dimensions coupled to massless adjoint fermions. With all fields in the adjoint representation the gauge group is actually SU(2)/Z_2, which possesses nontrivial topology. In particular, there are two distinct topological sectors and the physical vacuum state has a structure analogous to a θvacuum. We show how this f

Jakub Rembielinski, Pawel Caban

In this paper we describe a covariant canonical formalism for a free time-like (massive) as well as space-like (tachyonic) particle in the framework of nonstandard synchronization scheme. In this scheme one is able to introduce absolute causality without breaking the Poincaré invariance.

E. Ragoucy

We present an algebraic approach to string theory, using a Hamiltonian reduction of N=2 WZW models. An embedding of sl(1|2) in a Lie superalgebra determines a niltopent subalgebra. Chirally gauging this subalgebra in the corresponding WZW action leads to an extension of the N=2 superconformal algebra. We classify all the embeddings of sl(1|2) into Lie supera

J. Ambjorn, M. Carfora, A. Marzuoli

We discuss the geometry of dynamical triangulations associated with 3-dimensional and 4-dimensional simplicial quantum gravity. We provide analytical expressions for the canonical partition function in both cases, and study its large volume behavior. In the space of the coupling constants of the theory, we characterize the infinite volume line and the associ

M. Navarro, V. Aldaya, M. Calixto

A new, configuration-space picture of a formalism of group quantization, the GAQ formalism, is presented in the context of a previous, algebraic generalization. This presentation serves to make a comprehensive discussion in which other extensions of the formalism, particularly to incorporate gauge symmetries, are developed as well. Both images are combined i

Tatsuo Kobayashi, Hiroaki Nakano

``Anomalous&#39;&#39; U(1) gauge symmetry with Green-Schwarz anomaly cancellation mechanism is discussed in the orbifold construction of four-dimensional heterotic string models. Some conditions are given as criteria to have ``anomalous&#39;&#39; U(1) in orbifold string models. In particular, ``anomalous&#39;&#39; U(1) is absent if the massless twisted matte

H. Nicolai, D. Korotkin, H. Samtleben

In these lectures we report recent work on the exact quantization of dimensionally reduced gravity, i.e. 2d non-linear (G/H)-coset space sigma-models coupled to gravity and a dilaton. Using methods developed in the context of flat space integrable systems, the Wheeler-DeWitt equations for these models can be reduced to a modified version of the Knizhnik-Zamo

Phillial Oh, Q-Han Park

We consider the (2+1)-dimensional gauged Heisenberg ferromagnet model coupled with the Chern-Simons gauge fields. Self-dual Chern-Simons solitons, the static zero energy solution saturating Bogomol&#39;nyi bounds, are shown to exist when the generalized spin variable is valued in the Hermitian symmetric spaces G/H. By gauging the maximal torus subgroup of H,

Yung Su Tsai

If CP is violated in any decay process involving leptons it will signify the existense of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. We discuss the signatures of CP violation in (1) the decay of tau lepton, and (2) the semileptonic decay of $π$, K, D, B and t

John Womersley

Strategies are presented for discovering light, color-singlet technipions (pi_T) produced in association with a vector boson through s-channel technirho production, at the Tevatron and LHC. Signal and W+jets background were simulated including detector effects. Tagging of b-quarks from the pi_T -> bb decay is found to be important to reduce the W+jets backgr

V. Barger, M. S. Berger, J. F. Gunion, T. Han

We demonstrate that a measurement of the Bjorken process $e^+e^-, μ^+μ^-\to ZH$ in the threshold region can yield a precise determination of the Higgs boson mass. With an integrated luminosity of $100 fb^{-1}$, it is possible to measure the Higgs mass to within 60 MeV (100 MeV) for m_H=100 GeV (150 GeV).

Stefan Güllenstern, Oliver Martin, Pawel Gornicki, Lech Mankiewicz

We present the updated long write-up for version 1.1 of the SPHINX Monte Carlo. The program can be used to simulate polarized nucleon - nucleon collisions at high energies. Spins of colliding particles are taken into account. The program allows the calculation of cross sections for various processes.

J. C. Romao, S. D. Rindani, J. W. F. Valle

We discuss some rare Z decay signatures associated with extensions of the Standard Model with spontaneous lepton number violation at the electroweak scale. We show that single-photon Z decays such as $Z \to γH$ and $Z \to γJ J$ where H is a CP-even Higgs boson and J denotes the associated CP-odd Majoron may occur with branching ratios accessible to LEP sensi

B. Bajc, S. Fajfer, Robert J. Oakes

Assuming the ${\bar D}^0, D^-, D^-_s$ and $B^+, B^0, B_s^0$ mesons belong to triplets of SU(3) flavor symmetry, we analyse the form factors in the semileptonic decays of these mesons. Both quark and meson mass differences are taken into account. We find a number of relations, in agreement with the present data as well as with previous analyses, and predict c

Vasily V. Kabachenko, Yury F. Pirogov

The unified compositeness of leptons, quarks and Higgs bosons is proposed as a possible scenario for New Physics beyond the Standard Model. The following topics of the scenario are briefly discussed: - Chiral gauge exceptional symmetry E_6 as a strong internal binding mechanism; - Higgs doublet as a composite Goldstone boson; - Nonlinear Standard Model as a

M. A. Braun, V. V. Vechernin

A microscopic treatment of cumulative phenomena based on perturbative QCD calculations of the corresponding quark diagrams near the threshold is presented. To sum all diagrams like these the special technique based on the recurrence relations was developed. The x-behaviour of the nuclear structure function $F_{2}(x)$ in the cumulative region x>1 was found to

W. Bietenholz, R. Brower, S. Chandrasekharan, U. -J. Wiese

We construct a perfect lattice action for staggered fermions by blocking from the continuum. The locality, spectrum and pressure of such perfect staggered fermions are discussed. We also derive a consistent fixed point action for free gauge fields and discuss its locality as well as the resulting static quark-antiquark potential. This provides a basis for th

K. Kajantie, M. Laine, K. Rummukainen, M. Shaposhnikov

The continuum 3d SU(2)$\times$U(1)+Higgs theory is an effective theory for a large class of 4d high-temperature gauge theories, including the minimal standard model and some of its supersymmetric extensions. We study the effects of the U(1) subgroup using lattice Monte Carlo techniques. When $g&#39;^2/g^2$ is increased from the zero corresponding to pure SU(

T. R. Klassen

I present a brief summary of the status and prospects of improved Wilson-type quark actions for coarse lattice simulations. My conclusions are optimistic.

Donald Witt, Kristin Schleich

General relativity exhibits a unique feature not represented in standard examples of chaotic systems; it is a spacetime diffeomorphism invariant theory. Thus many characterizations of chaos do not work. It is therefore necessary to develop a definition of chaos suitable for application to general relativity. This presentation will present results towards thi

W. Kummer

General matterless models of gravity include dilaton gravity, arbitrary powers in curvature, but also dynamical torsion. They are a special class of &#34;Poisson-sigma-models&#34; whose solutions are known completely, together with their general global structure. Beside the ordinary black hole, arbitrary singularity structures can be studied. It is also poss

J. -Q. Liang, H. J. W. Mueller-Kirsten, Jian-Ge Zhou

Starting from the coherent state representation of the evolution operator with the help of the path-integral, we derive a formula for the low-lying levels $E = ε_0 - 2\triangleεcos (s+ξ)π$ of a quantum spin system. The quenching of macroscopic quantum coherence is understood as the vanishing of $cos (s+ξ)π$ in disagreement with the suppression of tunneling (

E. Akkermans, J. E. Avron, R. Narevich, R. Seiler

For two dimensional Schroedinger Hamiltonians we formulate boundary conditions that split the Hilbert space according to the chirality of the eigenstates on the boundary. With magnetic fields, and in particular, for Quantum Hall Systems, this splitting corresponds to edge and bulk states. Applications to the integer and fractional Hall effect and some open p

Tomaso Aste

Random walks are studied on disordered cellular networks in 2-and 3-dimensional spaces with arbitrary curvature. The coefficients of the evolution equation are calculated in term of the structural properties of the cellular system. The effects of disorder and space-curvature on the diffusion phenomena are investigated. In disordered systems the mean square d

U. Zuelicke, R. Bluhm, V. A. Kostelecky, A. H. MacDonald

The quantum Hall effect is necessarily accompanied by low-energy excitations localized at the edge of a two-dimensional electron system. For the case of electrons interacting via the long-range Coulomb interaction, these excitations are edge magnetoplasmons. We address the time evolution of localized edge-magnetoplasmon wave packets. On short times the wave

C. Wexler, D. J. Thouless

An alternative approach to the derivation of the force on a vortex based in an adiabatic approximation in the action of the superfluid system is developed. Assuming that the vortex motion is relatively slow compared with the characteristic times involved in the microscopic degrees of freedom, the effect of the superfluid and its excitations is reduced to a g

R. Giovanelli, M. Haynes, L. da Costa, W. Freudling

The use of the Tully-Fisher (TF) relation for the determination of the Hubble Constant relies on the availability of an adequate template TF relation and of reliable primary distances. Here we use a TF template relation with the best available kinematical zero-point, obtained from a sample of 24 clusters of galaxies extending to cz ~ 9,000 km/s, and the most

F. Hammer, H. Flores, S. J. Lilly, David Crampton

The spectral properties of more than 400 CFRS galaxies and their changes over the redshift interval 0 - 1.3 are investigated. Emission line intensities and equivalent widths for accessible lines have been measured, as well as continuum color indices based on 200A wide spectral regions. Within the CFRS sample, the comoving fraction of galaxies with significan

Stacy S. McGaugh, W. J. G. de Blok

We show that the gas mass fraction of spiral galaxies is strongly correlated with luminosity and surface brightness. It is not correlated with linear size. Gas fraction varies with luminosity and surface brightness at the same rate, indicating evolution at fixed size. Dim galaxies are clearly less evolved than bright ones, having consumed only $\sim 1/2$ of

J. A. Sellwood, M. Valluri

We have examined the stability of a sequence of oblate elliptical galaxy models having the Stackel form suggested by Kuz&#39;min & Kutuzov. We have employed the 2-integral DFs given by Dejonghe & de Zeeuw for which flattened non-rotating models are characterized by counter-streaming motion and are radially cool; we introduce net rotation in some models by ch

P. O. Hulth, :, The AMANDA Collaboration

At the AMANDA South Pole site, four new holes were drilled to depths 2050 m to 2180 m and instrumented with 86 photomultipliers (PMTs) at depths 1520-2000 m. Of these PMTs 79 are working, with 4-ns timing resolution and noise rates 300 to 600 Hz. Various diagnostic devices were deployed and are working. An observed factor 60 increase in scattering length and

Karl Mannheim

The discovery of rapid and simultaneous TeV/optical (UV, X-ray) variability provides strong evidence against the interaction between a thermal radiation field produced by an accretion flow and relativistic electrons in a jet as the origin of the gamma-rays in BL Lacertae objects. Synchrotron-self-Compton scattering (SSC) or proton-initiated cascades (PIC) re