December 1997 arXiv papers — page 7

M. Coleman Miller

The remarkable discovery of kilohertz quasi-periodic brightness oscillations (QPOs) in the accretion-powered emission from some sixteen neutron-star low-mass X-ray binary systems has led to much speculation about and theoretical modeling of the origin of these oscillations. It has also led to intense study of the implications that these QPOs have for the pro

E. V. Gotthelf, V. M. Kaspi

We have detected significant X-ray emission from the direction of the young radio pulsar PSR J1105-6107 using the ASCA Observatory. The 11 sigma detection includes 460 background-subtracted source counts derived using data from all four ASCA detectors. The emission shows no evidence of pulsations; the pulsed fraction is less than 31%, at the 90% confidence l

T. E. Strohmayer, E. E. Fenimore, T. Murakami, A. Yoshida

We summarize the spectral characteristics of a sample of 22 bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2 - 400 keV range, providing a unique opportunity to characterize the largely unexplored X-ray prop

J. K"oppen, Ch. Theis, G. Hensler

The network of interactions between hot gas, cool clouds, massive stars, and stellar remnants used in the chemodynamical modeling of the interstellar medium is investigated for the types of its solutions. In a physically consistent formulation for the energy transfer during condensation, oscillations due to a cyclic switching between condensation and evapora

David M. Goldberg, Przemyslaw Wozniak

We measure the astrometric shifts of the light centroids for the microlensing events in the OGLE-1 database. Of the 15 consistently detected events, 7 had significant shifts which we were able to measure with a fair degree of confidence. Those events with large shifts are also expected to be unresolved with a background ``blend'', and thus, we sugges

Ulysses J. Sofia, Edward B. Jenkins

We use the absorption features from neutral argon at 1048 and 1066 A to determine interstellar abundances or their lower limits toward nine early-type stars. These features were observed with the Interstellar Medium Absorption Profile Spectrograph (IMAPS) along sight lines with low reddening and low fractional abundances of molecular hydrogen. We find that t

Martin G. Haehnelt, Priyamvada Natarajan, Martin J. Rees

We demonstrate that the luminosity function of the recently detected population of star-forming galaxies and the QSO luminosity function at z=3 can be matched with the mass function of dark matter haloes predicted by hierarchical cosmogonies for lifetimes of optically bright QSOs in the range 10^6 to 10^8 yr. We suggest that the mass of supermassive black ho

S. C. Trager, Guy Worthey, S. M. Faber, David Burstein

We present absorption-line strengths on the Lick/IDS line-strength system of 381 galaxies and 38 globular clusters in the 4000--6400 \AA region. All galaxies were observed at Lick Observatory between 1972 and 1984 with the Cassegrain Image Dissector Scanner spectrograph, making this study one of the largest homogeneous collections of galaxy spectral line dat

Marek Gierlinski, Andrzej A. Zdziarski, Paolo S. Coppi, Juri Poutanen

We analyze X-ray/gamma-ray observations of Cyg X-1 in the soft state. We find the hybrid thermal/non-thermal model fits the data very well. The significant contribution from the non-thermal electrons is required to account for the observed power law extending without a break to at least 800 keV. The presence of electron-positron pairs in the hot source is un

István Szapudi, E. Gaztañaga

Clustering statistics are compared in the Automatic Plate Machine (APM) and the Edinburgh/Durham Southern Galaxy Catalogue (EDSGC) angular galaxy surveys. Both surveys were independently constructed from scans of the same adjacent UK IIIa--J Schmidt photographic plates with the APM and COSMOS microdensitometers, respectively. The comparison of these catalogs

L. Sidoli, G. L. Israel, L. Chiappetti, A. Treves

During the $BeppoSAX$ survey of the Galactic Center region, we have discovered X-ray emission from the central region of the supernova remnant G0.9+0.1. The high interstellar absorption (N_H about 3 times 10^{23} cm^-2) is consistent with a distance of order of 10 kpc and, correspondingly, an X-ray luminosity of about 10^{35} erg s^{-1}. Although we cannot c

S. Mereghetti, L. Stella, G. L. Israel

The ''Anomalous X-ray Pulsars'' (AXPs) are a small group of X-ray pulsars characterized by periods in the 5-10 s range and by the absence of massive companion stars. There are now 7 possible members of this class of objects. We review recent observational results on their X-ray spectra, spin period evolution, and searches for orbital motion a

C. L. Carilli, D. E. Harris, L. Pentericci, H. J. A. Rottgering

We present X-ray observations of the narrow line radio galaxy 1138-262 at z = 2.156 with the High Resolution Imager (HRI) on ROSAT. Observations at other wave-bands, and in particular extremely high values of Faraday rotation of the polarized radio emission, suggest that the 1138-262 radio source is in a dense environment, perhaps a hot, cluster-type atmosph

M. J. Rees, P. Meszaros

We consider fireball models where the ejecta have a range of bulk Lorentz factors, so that the inner (lower $Γ$) parts may carry most of the mass, or even most of the energy. The outer shock and contact discontinuity decelerate as the fireball sweeps up external matter. This deceleration allows slower ejecta to catch up, replenishing and reenergizing the rev

L. Chiappetti, G. Cusumano, S. Del Sordo, M. C. Maccarone

We report the current status of the analysis of the MECS background using the entire dataset of the BeppoSAX Science performance Verification Phase. We have collected 360 ks of dark Earth instrumental background, 470 ks of bright Earth background and 1100 ks of blank field data. We are attempting to model the instrumental background in terms of its various c

C. Vignali, A. Comastri, G. M. Stirpe, M. Cappi

ASCA X-ray spectral analysis of the Seyfert 2 galaxy IRAS 04575-7537 is presented. The main result is the presence of a significant iron edge at a rest energy of 7.13^+0.21_-0.16 keV. The spectrum is flat (Gamma = 1.5) with a substantial absorption Nh = 10^22 cm^-2 and does not require any reflection component. There is also evidence of a narrow Fe Kalpha em

L. Chiappetti, F. Haardt, A. Treves, D. Ricci

GX 339-4 has been observed by BeppoSAX twice in spring 1997 as part of a longer monitoring program. The source was close to the highest levels (50 mCrab) of the extended low state (as measured by the XTE ASM during the last 2 years). Its spectrum was quite hard, similar to the Exosat 1984 off state, but 40 times stronger. The source is detected up to more th

M. Guainazzi, A. Comastri, G. Stirpe, W. N. Brandt

The preliminary results of the BeppoSAX observation of the radio-quiet AGN 1H0419-577 are presented. Despite its broad line optical spectrum, the intermediate X-ray spectrum (i.e. 2--10 keV) is flatter than typically observed in Seyfert 1s and no iron line is significantly detected. Even more intriguingly, a 1992 ROSAT pointed observation suggests a dramatic

Heino Falcke, M. J. Rieke, G. H. Rieke, Chris Simpson

We present near-infrared spectra obtained to search for Pa-alpha and molecular hydrogen lines in edge-darkened (FR I-type) radio galaxies with bright Halpha emission in the redshift range 0.0535<z<0.15. We find that all three galaxies in our sample (PKS 0745-191, PKS 1346+26, & PKS2322-12) which are associated with strong cooling flows also have strong Pa-al

Juan Fabregat, Jose M. Torrejon

We present an empirical calibration of the uvby-beta photometric system to determine the intrinsic colours and indices and the astrophysical parameters of the underlying star, valid for Be stars earlier than B5. The procedure allows the determination of the interstellar reddening with an accuracy of 0.033 mag. (rms), and the absolute magnitude with an accura

M. A. Abramowicz, V. Karas, A. Lanza

We further investigate the runaway instability of relativistic tori around black holes assuming a power law distribution of the specific angular momentum. We neglect the self-gravity of the torus; thus the gravitational field of the system is determined by the central rotating black hole alone (the Kerr geometry). We find that for any positive (i.e. consiste

H. Lin, H. K. C. Yee, R. G. Carlberg, S. L. Morris

The CNOC2 Field Galaxy Redshift Survey presently contains some 5000 galaxy redshifts, plus extensive UBgRI photometry, and is the largest galaxy sample at moderate redshifts 0.1 < z < 0.6. Here we present some preliminary results on the galaxy luminosity function (LF) and its redshift evolution, using a sample of R < 21.5 CNOC2 galaxies, subdivided into earl

W. Kluzniak

If the observed millisecond variability in the X-ray flux of several neutron-star low-mass X-ray binaries (LMXBs) is interpreted within a general-relativistic framework (Kluzniak, Michelson \& Wagoner 1990) extant at the time of discovery, severe constraints can be placed on the equation of state (e.o.s.) of matter at supranuclear densities. The reported max

Maulik K. Parikh, Frank Wilczek

The membrane paradigm is the remarkable view that, to an external observer, a black hole appears to behave exactly like a dynamical fluid membrane, obeying such pre-relativistic equations as Ohm&#39;s law and the Navier-Stokes equation. It has traditionally been derived by manipulating the equations of motion. Here we provide an action formulation of this pi

A. Mironov, A. Morozov

The (generalized) WDVV equations for the prepotentials in $2d$ topological and $4,5d$ Seiberg-Witten models are covariant with respect to non-linear transformations, described in terms of solutions of associated linear problem. Both time-variables and the prepotential change non-trivially, but period matrix (prepotential&#39;s second derivatives) remains int

J. I. Katz, T. Piran

The discovery by BeppoSAX and coordinated ground-based observations of persistent X-ray, visible and radio counterparts to GRB has successfully concluded a search begin in 1973. The problem of explaining the mechanisms of GRB and their persistent counterparts remains. There are two classes of models: 1) GRB continue weakly for days at all frequencies; 2) GRB

M. D. Scadron

First we summarize the quark-level linear $σ$ model compositeness conditions and verify that indeed $m_σ= 2 m_q$ when $m_π= 0$ and $N_c=3$, rather than in the $N_c\to\infty$ limit, as is sometimes suggested. Later we show that this compositeness picture also predicts a chiral symmetry restoration temperature $T_c = 2f_π$, where $f_π$ is the pion decay consta

V. Borodulin, G. Jikia

The two-loop corrections to the electroweak gauge bosons quartic couplings growing quadratically with the Higgs boson mass are calculated in the Standard Model in the limit of large Higgs mass. The corrections to WWWW, WWZZ and ZZZZ four-vertices are found to be an order of magnitude larger than the two-loop m_H^2 corrections to light fermion and triple gaug

A. -L. Melchior

Recent surveys monitoring millions of light curves of resolved stars in the LMC have discovered several microlensing events. Unresolved stars could however significantly contribute to the microlensing rate towards the LMC. Monitoring pixels, as opposed to individual stars, should be able to detect stellar variability as a variation of the pixel flux. We pres

Pio Jose Arias, Adel Khoudeir

A massive gauge invariant formulation for scalar ($ϕ$) and antisymmetric ($C_{mnp}$) fields with a topological coupling, which provides a mass for the axion field, is considered. The dual and local equivalence with the non-gauge invariant proposal is established, but on manifolds with non-trivial topological structure both formulations are not globally equiv

A. Canavezes, V. Springel, S. J. Oliver, M. Rowan-Robinson

We investigate the topology of the new Point Source Catalogue Redshift Survey (PSCz) of IRAS galaxies by means of the genus statistic. The survey maps the local Universe with approximately 15000 galaxies over 84.1 per cent of the sky and provides an unprecedented number of resolution elements for the topological analysis. For comparison with the PSCz data we

R. Ketzmerick, K. Kruse, T. Geisel

We show that the time evolution operator of kicked quantum systems, although a full matrix of size NxN, can be diagonalized with the help of a new method based on a suitable combination of fast Fourier transform and Lanczos algorithm in just N^2 ln(N) operations. It allows the diagonalization of matrizes of sizes up to N\approx 10^6 going far beyond the poss

Nantel Bergeron, Frank Sottile

Given a finite graded poset with labeled Hasse diagram, we construct a quasi- symmetric generating function for (saturated) chains whose labels have fixed descents. This is a common generalization of a generating function for the flag f-vector defined by Ehrenborg and of a symmetric function associated to certain edge-labeled posets which arose in the theory

T. H. Koornwinder, F. A. Bais, N. M. Muller

We consider the quantum double D(G) of a compact group G, following an earlier paper. We use the explicit comultiplication on D(G) in order to build tensor products of irreducible *-representations. Then we study their behaviour under the action of the R-matrix, and their decomposition into irreducible *-representations. The example of D(SU(2)) is treated in

O. A. Borisenko, M. N. Chernodub, F. V. Gubarev

We discuss the abelian vortex dynamics in the abelian projection approach to non-abelian spin models. We show numerically that in the three-dimensional SU(2) spin model in the Maximal Abelian projection the abelian off-diagonal vortices are not responsible for the phase transition contrary to the diagonal vortices. A generalization of the abelian projection

Topi Kärki

We introduce a new localization principle which is a generalized canonical transformation. It unifies BRST localization, the non-abelian localization principle and a special case of the conformal Duistermaat-Heckman integration formula of Paniak, Semenoff and Szabo. The heat kernel on compact Lie groups is localized in two ways. First using a non-abelian gen

D. Jaksch, C. W. Gardiner, K. M. Gheri, P. Zoller

We use the quantum kinetic theory to calculate the steady state and the fluctuations of a trapped Bose-Einstein condensate at finite temperature. The system is divided in a condensate and a non-condensate part. A quantum mechanical description based on the number conserving Bogoliubov method is used for describing the condensate part. The non-condensed parti

H. Niggemann, G. Uimin, J. Zittartz

We consider thermodynamic properties, e.g. specific heat, magnetic susceptibility, of alternating Heisenberg spin chains. Due to a hidden Ising symmetry these chains can be decomposed into a set of finite chain fragments. The problem of finding the thermodynamic quantities is effectively separated into two parts. First we deal with finite objects, secondly w

Eung Jin Chun

We provide a simple solution to the $μ$ and strong CP problems in the context of gauge mediated supersymmetry breaking. The generic appearance of R symmetry in dynamical supersymmetry breaking is used to implement Peccei-Quinn symmetry. Acceptable $μ$ and $B$ terms as well as the large symmetry breaking scale are induced in the presence of nonrenormalizable

Yoshitaka Nakamura, Hidetoshi Fukuyama

Theoretical studies are presented on weak localization effects and magnetoresistance in quasi-one-dimensional systems with open Fermi surfaces. Based on the Wigner representation, the magnetoresistance in the region of weak field has been studied for five possible configurations of current and field with respect to the one-dimensional axis. It has been indic

Marc Kamionkowski

Inflation provides a unified paradigm for understanding the isotropy of the cosmic microwave background (CMB), the flatness problem, and the origin of large-scale structure. Although the physics responsible for inflation is not yet well understood, slow-roll inflation generically makes several predictions: a flat Universe, primordial adiabatic density pertur

L. I. Plimak, M. Fleischhauer, D. F. Walls

Matsubara Green&#39;s functions for interacting bosons are expressed as classical statistical averages corresponding to a linear imaginary-time stochastic differential equation. This makes direct numerical simulations applicable to the study of equilibrium quantum properties of bosons in the non-perturbative regime. To verify our results we discuss an oscill

Henry P. Stapp

David Mermin&#39;s recent paper with the same title as this one makes it clear that his claim to have found a gap in my reasoning rests on his claim that my argument violates a criterion for meaningfulness of counterfactual statements that I myself had set down. I set down no such requirement. But I am willing to accept it as a conservative sufficient condit

Michal Horodecki

We consider the problem of compression of the quantum information carried by ensemble of mixed states. We prove that for arbitrary coding schemes the least number of qubits needed to convey the signal states asymptotically faithfully is bounded from below by the Holevo function $S(\varrho)-\sum_ip_iS(\varrho_i)$. We also show that a compression protocol can

A. E. Allahverdyan, D. B. Saakian

The multi-access channels in quantum information theory are considered. Classical messages from independent sources, which are represented as some quantum states, are transported by a channel to one address. The messages can interact with each other and with external environment. After statement of problem and proving some general results we investigate phys

Wojciech Burkot

A hierarchical, reversible mapping between levels of tree structured computation, applicable for structuring the Quantum Computation algorithm for NP-complete problem is presented. It is proven that confining the state of a quantum computer to a subspace of the available Hilbert space, where states are consistent with the problem constraints, can be done in

Per K. Jakobsen, Valentin V. Lychagin

We introduce the notion of difference equation defined on a structured set. The symmetry group of the structure determines the set of difference operators. All main notions in the theory of difference equations are introduced as invariants of the symmetry group. Linear equations are modules over the skew group algebra, solutions are morphisms relating a give

M. Irac-Astaud, G. Rideau

Deformed Harmonic Oscillator Algebras are generated by four operators, two mutually adjoint $a$ and $a^\dagger$, and two self-adjoint $N$ and the unity $1$ such as: $[a,N] = a, [a^\dagger, N]= -a^\dagger, a^\dagger a = ψ(N)$ and $aa^\dagger =ψ(N+1)$. The Bargmann Hilbert space is defined as a space of functions, holomorphic in a ring of the complex plane, eq

Marian Boguna, Josep M. Porra, Jaume Masoliver, Katja Lindenberg

The phenomenon of resonant activation of a Brownian particle over a fluctuating barrier is revisited. We discuss the important distinctions between barriers that can fluctuate among &#34;up&#34; and &#34;down&#34; configurations, and barriers that are always &#34;up&#34; but that can fluctuate among different heights. A resonance as a function of the barrier

Joaquim A. Dente, R. Vilela Mendes

Principal component analysis (PCA) algorithms use neural networks to extract the eigenvectors of the correlation matrix from the data. However, if the process is non-Gaussian, PCA algorithms or their higher order generalisations provide only incomplete or misleading information on the statistical properties of the data. To handle such situations we propose n

M. Kibler, M. Daoud

The Lie algebra of the classical group SU(2) is constructed from two quon algebras for which the deformation parameter is a common root of unity. This construction leads to (i) a not very well-known polar decomposition of the ladder generators of the SU(2) Lie algebra and to (ii) an alternative to the (J,M) quantization scheme, viz., the (J,alpha) quantizati

R. Aldrovandi, A. L. Barbosa, L. P. Freitas

A simple procedure to obtain complete, closed expressions for Lie algebra invariants is presented. The invariants are ultimately polynomials in the group parameters. The construction of finite group elements require the use of projectors, whose coefficients are invariant polynomials. The detailed general forms of these projectors are given. Closed expression

Feng Pan, Shihai Dong, J. P. Draayer

A new simple Young diagrammatic method for Kronecker products of O(n) and Sp(2m) is proposed based on representation theory of Brauer algebras. A general procedure for the decomposition of tensor products of representations for O(n) and Sp(2m) is outlined, which is similar to that for U(n) known as the Littlewood rules together with trace contractions from a

D. Bauer

Owing to its numerical simplicity, a two-dimensional two-electron model atom, with each electron moving in one direction, is an ideal system to study non-perturbatively a fully correlated atom exposed to a laser field. Frequently made assumptions, such as the ``single active electron&#39;&#39;- approach and calculational approximations, e.g. time dependent d

M. Yu. Kuchiev, V. N. Ostrovsky

Negative ion detachment in two-colour laser field is considered within the recent modification of Keldysh model which makes it quantitatively reliable. The general approach is illustrated by calculation of angular differential detachment rates, partial rates for particular ATD (Above Threshold Detachment) channels and total detachment rates for H$^-$ ion in

G. A. Lalazissis, K. Hara

All available experimental data for the $ΔI=2$ transition energies in superdeformed bands are analyzed by using a new one-point formula. The existence of deviations from the smooth behavior is confirmed in many bands. However, we stress that one cannot necessarily speak about staggering patterns as they are mostly irregular. Simulations of the experimental d

V. Koch, J. Randrup, X. N. Wang, Y. Kluger

Disoriented chiral condensates are manifested as long wavelength pionic oscillations and their interaction with the thermal environment can be a significant source of dileptons. We calculate the yield of such dilepton production within the linear sigma model and illustrate the basic features of the dilepton spectrum in a schematic model. We find that the dil

Masayuki Matsuzaki, Peter Ring

Effects of the Fermi-sea polarization on the superfluidity in nuclear matter are studied in a framework of quantum hadrodynamics. The particle-hole polarization due to $σ$ and $ω$ mesons enhances the peak value of the pairing gap contrary to the previous non-relativistic studies.

Nantel Bergeron, Frank Sottile

Structure constants for the multiplication of Schubert polynomials by Schur symmetric polynomials are known to be related to the enumeration of chains in a new partial order on S_\infty, which we call the universal k-Bruhat order. Here we present a monoid M for this order and show that $M$ is analogous to the nil-Coxeter monoid for the weak order on S_\infty

C. A. Athanasiadis, J. A. De Loera, V. Reiner, F. Santos

The cyclic polytope $C(n,d)$ is the convex hull of any $n$ points on the moment curve ${(t,t^2,...,t^d):t \in \reals}$ in $\reals^d$. For $d&#39; >d$, we consider the fiber polytope (in the sense of Billera and Sturmfels) associated to the natural projection of cyclic polytopes $π: C(n,d&#39;) \to C(n,d)$ which &#34;forgets&#34; the last $d&#39;-d$ coordinat

Fabio Riccioni

We construct the complete coupling of $(2,0)$ supergravity in six dimensions to $n$ tensor multiplets, extending previous results to all orders in the fermi fields. The truncation to $(1,0)$ supergravity coupled to tensor multiplets exactly reproduces the complete couplings recently obtained.

Florin Constantinescu, G&#34;unter Scharf

We prove unboundedness and boundedness of the unsmeared and smeared chiral vertex operators, respectively. We use elementary methods in bosonic Fock space, only. Possible applications to conformal two - dimensional quantum field theory, perturbation thereof, and to the perturbative construction of the sine-Gordon model by the Epstein-Glaser method are discus

HM Chan, ST Tsou

The Dualized Standard Model which has a number of very interesting physical consequences is itself based on the concept of a nonabelian generalization to electric-magnetic duality. This paper explains first the reasons why the ordinary (Hodge) * does not give duality for the nonabelian theory and then reviews the steps by which these difficulties are surmoun

R. Argurio

A general rule determining how extremal branes can intersect in a configuration with zero binding energy is presented. It is derived in a model independent way and without explicit use of supersymmetry, solving a set of classical equations of motion. When specializing to M and type II theories, it is shown that some intersection rules can be consistently int

Matthias Doerrzapf

We derive the embedding structure of unitary N=2 minimal models and show as a result that these representations have a degeneration of uncharged singular states. This corrects some earlier mistakes made in the literature. We discuss the connexion to the N=2 character formulae and finally give a proof for the embedding diagrams.

P. Vanhove

The study of the special F^4 and R^4 in the effective action for the Spin(32)/Z_2 and type II strings sheds some light on D-brane calculus and on instanton contribution counting. The D-instanton case is discussed separately.

D. V. Antonov

The next-to-leading term in the weight factor of the string representation of the &#39;t Hooft loop average defined on the string world-sheet is found in the Abelian Higgs Model near the Londons&#39; limit. This term emerges due to the finiteness of the coupling constant and, in contrast to the Londons&#39; limit, where only the bilocal cumulant in the expan

F. M. Borzumati, G. R. Farrar, N. Polonsky, S. Thomas

The possibility of radiative generation of fermion masses from soft supersymmetry breaking chiral flavor violation is explored. Consistent models are identified and classified. Phenomenological implications for electric dipole moments and magnetic moments, as well as collider probes -- in particular those relevant at the Higgs resonance -- are discussed. It

Hsin-Chia Cheng

Supersymmetric theories generally have new flavor and CP violation sources in the squark and slepton mass matrices. They will contribute to the lepton flavor violation processes, such as $μ\to e γ$, which can be probed far below the current bound with an intense muon source at the front end of the muon collider. In addition, if sleptons can be produced at th

Laura Reina

We illustrate the possibility of observing signals from Flavor Changing Neutral Currents, originating from the scalar sector of a Two Higgs Doublet Model. In particular, we focus on the tree level process mu^+ mu^- --> tbar c + cbar t, via scalar exchange in the s-channel, as a distinctive process for mu^+ mu^- colliders.

M. K. Parida, B. Purkayastha, S. Dey

In recent analyses the existence of $SU(2)_L\times\SU(2)_R\times\SU(4)_C(g_{2L}\ne g_{2R})$ intermediate gauge symmetry has been ruled out in SUSY SO(10) model at one-loop level, although the left-right symmetric intermediate gauge group has been shown to exist with certain light scalar superfields near 1 TeV.We show,how the asymmetric gauge group is allowed

N. V. Mikheev, O. S. Ovchinnikov, L. A. Vassilevskaya

The axion decay into electron-positron pair $a \to e^+ e^-$ is studied in an external magnetic field in KSVZ-model where axions have only induced coupling to leptons. The axion lifetime in the field decreases with energy and field strength to seconds.

John Swain, Lucas Taylor

The magnitudes of the CKM matrix elements $V_{td}$, $V_{ts}$, and $V_{tb}$ are determined for the first time without any assumptions of unitarity. The implications for the unitarity of the CKM matrix as a whole are discussed.

John Swain, Lucas Taylor

We present a new method for the determination of the Cabibbo-Kobayashi-Maskawa quark mixing matrix element $|V_{tb}|$ from electroweak loop corrections, in particular those affecting the process $Z\to b\bar{b}$. From a combined analysis of results from the LEP, SLC, Tevatron, and neutrino scattering experiments we determine $|V_{tb}| = 0.77^{+0.18}_{-0.24}$.

Roberto Pittau

The method introduced in a previous paper to simplify the tensorial reduction in multi-leg loop calculations is extended to generic one-loop integrals, with arbitrary internal masses and external momenta.

I. Caprini, L. Lellouch, M. Neubert

Dispersive constraints on the shape of the form factors which describe the exclusive decays B -> D^(*) l nu are derived by fully exploiting spin symmetry in the ground-state doublet of heavy-light mesons. The analysis includes all twenty B^(*) -> D^(*) semileptonic form factors. Heavy-quark symmetry, with both short-distance and 1/m_Q corrections included, i

Tadeusz Wibig

The inelasticity in nucleus-nucleus collisions at high energies is calculated in the framework of geometrical multichain model. The very fast increase of the inelasticity is found as a result of a second-stage cascading process. The same behaviour is expected for all the models using the wounded nucleon idea. The simple formula for the number of wounded nucl

Subhendra Mohanty, Jose F. Nieves, Palash B. Pal

For photons that propagate through a gas of neutrinos with a non-zero chemical potential, the left-handed and right-handed polarization modes acquire different dispersion relations. This is due to the CP and CPT-odd terms induced by such a background on the photon self-energy. We present a detailed calculation of this effect, which does not depend on any phy

B. -J. Schaefer, H. J. Pirner

We derive nonperturbative flow equations within an effective constituent quark model for two quark flavors. Heat-kernel methods are employed for a renormalization group improved effective potential. We study the evolution of the effective potential with respect to an infrared cutoff scale $k$ at vanishing temperature. At the first stage we omit corrections c

A. Bartl, H. Eberl, S. Kraml, W. Majerotto

We discuss the production of stops at a $μ^+ μ^-$ collider. We present numerical predictions for the cross sections within the Minimal Supersymmetric Standard Model. In particular we consider stop production near $\sqrt{s} = m_{H^0}$ and $\sqrt{s} = m_{A^0}$.

A. M. Gavrilik

We show that application of quantum unitary groups, in place of ordinary flavor SU(n_f), to such static aspects of hadron phenomenology as hadron masses and mass formulas is indeed fruitful. The so-called q-deformed mass formulas are given for octet baryons (1/2)^+ and decuplet baryons (3/2)^+, as well as for the case of vector mesons 1^- involving heavy fla

M. Hirai, S. Kumano, M. Miyama

We investigate numerical solution of the Dokshitzer-Gribov-Lipatov-Altarelli- Parisi (DGLAP) Q^2 evolution equation for the transversity distribution Delta_T q or the structure function h_1. The leading-order (LO) and next-to- leading-order (NLO) evolution equations are studied. The renormalization scheme is MS or overline{MS} in the NLO case. Dividing the v

Mohan Narayan, G. Rajasekaran, S. Uma Sankar

We analyze the recent result of the CHOOZ collaboration in the context of mixing and oscillations between all the three neutrino flavors. If one assumes a hierarchy among the vacuum mass eigenvalues (\delta_{21} \ll \delta_{31}), then the CHOOZ result limits the (13) mixing angle \phi to quite small values. This in turn limits the contribution of the \nu_e <

Jyh-Liong Lim, Hsiang-nan Li

We propose a modified Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation for the summation of large $\ln(1/x)$, $x$ being the Bjorken variable, which contains an extra dependence on momentum transfer $Q$ compared to the conventional BFKL equation. This $Q$ dependence comes from the phase space constraint for soft real gluon emissions in the derivation of the BFKL

N. M. Shumeiko, J. G. Suarez

Principal contributions to QED radiative effects for Moller scattering of polarized particles are investigated both on the Born level and taking into account radiative corrections (RC). Scattering on the case of longitudinal and transversal polarized targets is also considered. In a general way the expressions for differential cross section and polarization

A. W. Thomas

While much attention has been focussed on the successes of perturbative QCD in describing the $Q^2$-dependence of deep-inelastic structure functions, the starting distributions themselves contain important, non-perturbative information on the structure of the nucleon, which has been somewhat neglected. We review some of the most important, recent discoveries

Naoyuki Haba

In N=1 Supersymmetric gauge theories, we can calculate non-perturbative effects in the superpotential. It is interesting to apply this effect to the phenomenology. We show two models here. One is the low energy supersymmetry (SUSY) breaking scenario without messenger sector, and the second is the composite model generating Yukawa interaction dynamically.

CLEO Collaboration, M. Artuso et al

We present a measurement of the absolute branching fraction for $D^0 -> K^- pi^+$ using the reconstruction of the decay chain $Bbar -> D^{*+} X l^- nubar $, $D^{*+} -> D^0 pi^+$ where only the lepton and the low-momentum pion from the $D^{*+}$ are detected. With data collected by the CLEO II detector at the Cornell Electron Storage Ring, we have determined $

M. Carena, R. L. Culbertson, S. Eno, H. J. Frisch

We review the status of searches for Supersymmetry at the Tevatron Collider. After discussing the theoretical aspects relevant to the production and decay of supersymmetric particles at the Tevatron, we present the current results for Runs Ia and Ib as of the summer of 1997. To appear in the book &#34;Perspectives in Supersymmetry&#34;, edited by G.L. Kane,

Thierry Kauffmann

We showed in a previous paper that a wide class of nonmetric theories of gravity encompassed by the $χg$ formalism predict that the speed of light rays depends on the their polarization direction relative to directions singled out by the gravitational field. This gravity-induced birefringence of space is a violation of the Equivalence Principle and is due to

Piotr Jaranowski, Gerhard Schaefer

The paper presents the conservative dynamics of two-body point-mass systems up to the third post-Newtonian order ($1/c^6$). The two-body dynamics is given in terms of a higher order ADM Hamilton function which results from a third post-Newtonian Routh functional for the total field-plus-matter system. The applied regularization procedures, together with maki

A. Geitner, H. Dehnen

Within a spin-gauge theory of gravity unified with the electroweak interaction we start with totally symmetric left- and right-handed fermions and explain the parity violation by symmetry breaking in such a way that the $W^{\pm}$-bosons couple only to the left-handed leptons. Right-handed neutrinos exist and couple as the right-handed electrons only to the Z

E. N. Glass

Taub numbers are studied on asymptotically flat backgrounds with Killing symmetries. When the field equations are solved for a background spacetime and higher order functional derivatives (higher order variational derivatives of the Hilbert Lagrangean) are solved for perturbations from the background, such perturbed space-times admit zeroth, first, and secon

N. Dupuis, Victor M. Yakovenko

We study the effect of umklapp scattering on the magnetic-field-induced spin-density-wave phases, which are experimentally observed in the quasi-one-dimensional organic conductors of the Bechgaard salts family. Within the framework of the quantized nesting model, we show that umklapp processes may naturally explain sign reversals of the quantum Hall effect (

M. Dube, P. C. E. Stamp

We solve for the dynamics of a pair of spins, coupled to each other and also to an environmental sea of oscillators. The environment mediates an indirect interaction between the spins, causing both mutual coherence effects and dissipation. This model describes a wide variety of physical systems, ranging from 2 coupled microscopic systems (eg., magnetic impur

Mark Friesen, Paul Muzikar

In clean enough samples of the high-$T_c$ oxide materials, the phase transition into the superconducting state occurs along a first order line in the $H$-$T$ plane. This means that a two-phase region occurs in the B-$T$ plane, in which the liquid and solid vortex phases coexist. We discuss the thermodynamics of this two-phase region, developing formulae rela

E. G. D. Cohen, L. Rondoni

The phase space contraction and the entropy production rates of Hamiltonian systems in an external field, thermostatted to obtain a stationary state are considered. While for stationary states with a constant kinetic energy the two rates are formally equal for all numbers of particles N, for stationary states with constant total (kinetic and potential) energ

Edilson Vargas, Marcia C. Barbosa

We consider here a blend made of two types of polymers, $A$ and $B$, of different chemical nature. At high temperature the homogeneous mixture is cross-linked. As the temperature is lowered, the two species try to segregate but are kept together by the cross-links. We show that for inhomogeneous, non-regular and non-permanent cross-links, there is a complete

Edilson Vargas, Marcia C. Barbosa

The phase behavior of a cross-linked polymer blend made of two incompatible species, $A$ and $B$, of different chemical nature is analyzed. Besides a homogeneous phase, this system also exhibits two microphases and a phase of total segregation. The transition between the homogeneous and the microphase is continuous along a $λ$-line; a first-order phase bound

Igor Zutic, Oriol T. Valls

Many problems in computational magnetics involve computation of fields which decay within a skin depth $δ$, much smaller than the sample size $d$. We discuss here a novel perturbation method which exploits the smallness of $ε\equiv δ/ d$ and the asymptotic behavior of the solution in the exterior and interior of a sample. To illustrate this procedure we cons