June 1997 arXiv papers — page 16

F. De Fazio

We describe a theoretical approach to compute inclusive widths of heavy hadrons, based on a systematic expansion in the inverse powers of the heavy quark mass. The method reproduces quite well the experimental ratios of $B$ mesons lifetimes. As for $τ(Λ_b)/τ(B_d)$, we present a QCD sum rule calculation of the $O(m_b^{-3})$ contribution to $τ(Λ_b)$; we conclu

V. E. Lyubovitskij, E. Z. Lipartia, A. G. Rusetsky

The perturbative framework is developed for the calculation of the pi(+)pi(-) atom characteristics (energy level shift and lifetime) on the basis of the field-theoretical Bethe-Salpeter approach. A closed expression for the first-order correction to the pi(+)pi(-) atom lifetime has been obtained.

Harald Fritzsch

A simple breaking of the subnuclear democracy of the quarks leads to a mixing between the second and the third family, in agrement with observation. Introducing the mixing between the first and the second family, one finds an interesting pattern of maximal CP--violation as well as a complete determination of the elements of the CKM matrix and of the unitarit

R. Foot, R. R. Volkas

Ordinary-sterile neutrino oscillations can generate significant neutrino asymmetry in the early Universe. In this paper we extend this work by computing the evolution of neutrino asymmetries and light element abundances during the Big Bang Nucleosynthesis (BBN) epoch. We show that a significant electron-neutrino asymmetry can be generated in a way that is ap

K. Sridhar

Non-Relativistic QCD (NRQCD) has provided a consistent framework for the physics of quarkonia. The colour-octet Fock components predicted by NRQCD have important implications for the phenomenology of quarkonium production in experiments. We have considered the consequences of the colour-octet channels for the production of the $^1P_1$ charmonium state, $h_c$

Eiichi Takasugi

Neutrinoless double beta decay occurs through the magnetic coupling of dimension five, $λ_W/m_{ν*}$, among the excited electron neutrino $ν^*$, electron and $W$ boson if $ν^*$ is a massive Majorana neutrino. (λ_W m_W / m_{ν*}^2 |\frac{(m_*/m_W) +2}{(m_*/m_W +1)^2} -0.129{m_*/m_W} | <2.13\times 10^{-2}, where $λ_W$ is the relative strength, $m_{ν*}$ is the co

Roland Buergin

Dijet production is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies sqrt(s)_ee=161 and 172 GeV. Jets are reconstructed using a cone jet finding algorithm in the range |eta(jet)|<2 and E_T(jet)>3 GeV. The angular distributions of direct and double-resolved processes and the inclusive two-jet cross-section

ALEPH collaboration

The data recorded by the ALEPH experiment at LEP at centre-of-mass energies of 161 GeV and 172 GeV were analysed to search for sleptons, the supersymmetric partners of leptons. No evidence for the production of these particles was found. The number of candidates observed is consistent with the background expected from four-fermion processes and gammagamma-in

Alexander Gromov

The Bondi formula for calculation of the invariant mass in the Tolman- Bondi (TB) model is interprated as a transformation rule on the set of co-moving coordinates. The general procedure by which the three arbitrary functions of the TB model are determined explicitly is presented. The properties of the TB model, produced by the transformation rule are studie

Orfeu Bertolami

Non-trivial solutions in string field theory may lead to the spontaneous breaking of Lorentz invariance and to new tensor-matter interactions. It is argued that requiring the contribution of the vacuum expectation values of Lorentz tensors to account for the vacuum energy up to the level that $Ω_{0}^Λ = 0.5$ implies the new interactions range is $λ\sim 10^{-

O. M. Khudaverdian

The divergence-like operator on an odd symplectic superspace which acts invariantly on a specially chosen odd vector field is considered. This operator is used to construct an odd invariant semidensity in a geometrically clear way. The formula for this semidensity is similar to the formula of the mean curvature of hypersurfaces in Euclidean space.

Denis Bernard, Krzysztof Gawedzki, Antti Kupiainen

The anomalous scaling in the Kraichnan model of advection of the passive scalar by a random velocity field with non-smooth spatial behavior is traced down to the presence of slow resonance-type collective modes of the stochastic evolution of fluid trajectories. We show that the slow modes are organized into infinite multiplets of descendants of the primary c

Miroslav Kotrla, Milan Predota

We studied interplay between kinetic roughening and phase ordering in 1+1 dimensional single-step solid-on-solid growth model with two kinds of particles and Ising-like interaction. Evolution of both geometrical and compositional properties was investigated by Monte Carlo simulations for various strengths of coupling. We found that the initial growth is stro

Tai-Kai Ng

In this paper we propose a new way of organizing many-body perturbation theory in the Path-integral formulation where a set of quasi-particle wave-functionals $ψ$&#39;s are introduced and are identified with quasi-particles in Landau Fermi liquid theory. We show how Fermi liquid theory can be obtained through $ψ$&#39;s in this new framework of perturbation t

Yong-Jihn Kim, K. J. Chang

We study the effect of weak localization on the transition temperatures of superconductors using time-reversed scattered state pairs, and find that the weak localization effect weakens electron-phonon interactions. With solving the BCS $T_{c}$ equation, the calculated values for $T_c$ are in good agreement with experimental data for various two- and three-di

Y. S. Wu, Y. Yu, Y. Hatsugai, M. Kohmoto

Quasielectrons and quasiholes in the fractional quantum Hall liquids obey fractional (including nontrivial mutual) exclusion statistics. Their statistics matrix can be determined from several possible state-counting scheme, involving different assumptions on statistical correlations. Thermal activation of quasiparticle pairs and thermodynamic properties of t

Erika F. de Lima

This paper presents a corpus-based method to assign grammatical subject/object relations to ambiguous German constructs. It makes use of an unsupervised learning procedure to collect training and test data, and the back-off model to make assignment decisions.

M. Blank, T. Kruger, L. Pustyl&#39;nikov

Perturbations due to round-off errors in computer modeling are discontinuous and therefore one cannot use results like KAM theory about smooth perturbations of twist maps. We elaborate a special approximation scheme to construct two smooth periodic on the angle perturbations of the twist map, bounding the discretized map from above and from below. Using the

J. Touma, S. Tremaine

We construct a simple symplectic map to study the dynamics of eccentric orbits in non-spherical potentials. The map offers a dramatic improvement in speed over traditional integration methods, while accurately representing the qualitative details of the dynamics. We focus attention on planar, non-axisymmetric power-law potentials, in particular the logarithm

Ehud Cohen, Tsvi Piran

The recent discoveries of X-ray and optical counterparts for GRBs, and a possible discovery of a host galaxy, implies that a direct measurement of the red-shift of some GRBs host galaxies is eminent. We discuss the implications of such measurements. They could enable us to determine the GRBs luminosity distribution, the variation of the rate of GRBs with cos

K. G. Gayley, G. P. Zank, H. L. Pauls, P. C. Frisch

Redshifted L$α$ absorption toward $α$ Cen has been interpreted by Linsky & Wood (1996) and Frisch et al. (1996) as evidence for decelerated interstellar hydrogen piled up on the upstream side of the heliosphere. We utilize newly developed two-dimensional multi-fluid models of the solar wind interaction with the ISM to corroborate this interpretation by synth

C. A. Scharf, R. F. Mushotzky

Both the X-ray luminosity-temperature (L-T) relationship and the iron abundance distribution of galaxy clusters show intrinsic dispersion. Using a large set of galaxy clusters with measured iron abundances we find a correlation between abundance and the relative deviation of a cluster from the mean L-T relationship. We argue that these observations can be ex

P. F. Gonzalez-Diaz, C. L. Siguenza

Protein denaturing induced by supercooling is interpreted as a process where some or all internal symmetries of the native protein are spontaneously broken. Hence, the free-energy potential corresponding to a folding-funnel landscape becomes temperature-dependent and describes a phase transition. The idea that deformed vortices could be produced in the trans

Hagai Netzer, Bradley M. Peterson

Reverberation-mapping campaigns have revolutionized our understanding of AGN. They have allowed the direct determination of the broad-line region size, enabled mapping of the gas distribution around the central black hole, and are starting to resolve the continuum source structure. This review describes the recent and successful campaigns of the Internationa

A. Martinelli

In this work we discuss on the basis of the instantaneous recycling approximation the possibility of determining a relation between matter distribution (luminous and dark) in elliptical galaxies and the observed metallicity gradients. A particular case is developed in detail yielding an analitycal expression of the above relation.

L. Cambresy, N. Epchtein, E. Copet, B. de Batz

Massive, large scale star counts in the J band provided by the Deep Near Infrared Survey of the Southern Sky (DENIS) are used for the first time to draw out an extinction map of the Chamaeleon I dark cloud. We derived a 2 arcminutes resolution map of the cloud from J star counts within an area of 1.5 x 3 degres around the centre of the cloud using an adaptiv

P. N. Bhat

This talk is based on the Very High Energy Gamma Ray Astronomy observations planned to be carried out at Pachmarhi in the central Indian state of Madhya Pradesh using the well known atmospheric \v Cerenkov technique. The development of a ground based array of 25 \v Cerenkov telescopes is currently underway at Pachmarhi situated at an altitutde of about a kil

Kimyeong Lee, Piljin Yi

We study an infinite family of N=2 $Sp(2n)$ gauge theories that naturally arise from the D3-brane probe dynamics in F-theory. The matter sector consists of four fundamental and one antisymmetric tensor hyper multiplets. We propose that, in the limit of vanishing bare masses, the theory has exact $SO(8)\sdtimes SL(2,Z)$ duality. We examine the semiclassical B

S. P. Strong, B. Freedman, William Bialek, R. Koberle

Extending the classic works of Berg and Purcell on the biophysics of bacterial chemotaxis, we find the optimal chemotactic strategy for the peritrichous bacterium E. Coli in the high and low signal to noise ratio limits. The optimal strategy depends on properties of the environment and properties of the individual bacterium and is therefore highly adaptive.

Thomas Appelquist, John Terning, L. C. R. Wijewardhana

Using new insights into strongly coupled gauge theories arising from analytic calculations and lattice simulations, we explore a framework for technicolor model building that relies on a non-trivial infrared fixed point, and an essential role for QCD. Interestingly, the models lead to a simple relation between the electroweak scale and the QCD confinement sc

Anatoley T. Zheleznyak, Victor M. Yakovenko, H. D. Drew, I. I. Mazin

Ac and dc magnetotransport data in the normal state of YBa2Cu3O7 are analyzed within Fermi-liquid and non-Fermi-liquid models. In the Fermi-liquid analysis we use the Fermi surface deduced from band structure calculations and angular resolved photoemission experiments and assume that the electron relaxation rate varies over the Fermi surface. The non-Fermi-l

A. Silverberg, Yu. G. Zarhin

Given an abelian variety over a field with a discrete valuation, Grothendieck defined a certain open normal subgroup of the absolute inertia group. This subgroup encodes information on the extensions over which the abelian variety acquires semistable reduction. We study this subgroup, and use it to obtain information on the extensions over which the abelian

F. G. Pikus, K. K. Likharev

We have used a simple, analytically solvable model to analyze the characteristic s of dual-gate metal-oxide-semiconductor field-effect transistors (MOSFETs) with 10-nm-scale channel length L. The model assumes ballistic dynamics of 2D electrons in an undoped channel between highly doped source and drain. When applied to silicon n-MOSFETs, calculations show t

K. Petrovay, L. van Driel-Gesztelyi

In a statistical study of the decay of individual sunspots based on DPR data we find that the mean instantaneous area decay rate is related to the spot radius r and the maximal radius r0 as D=C r/r0, C=32.0 +- 0.26 MSH/day. This implies that sunspots on the mean follow a parabolic decay law; the traditional linear decay law is excluded by the data. The valid

L. Bergstrom, P. Ullio

For the first time, a full one-loop calculation of the process $χχ\to 2γ$ is performed, where $χ$ is the lightest neutralino in the minimal supersymmetric extension of the Standard Model. This process is of interest for dark matter detection, since it would give a sharp $γ$ ray line with $E_γ=m_χ$. We improve upon and correct published formulas, and give cro

Buell T. Jannuzi, Brian Yanny, Chris Impey

Hubble Space Telescope (HST) WFPC-2 I-band (F814W) images of three X-ray selected BL Lacertae objects (MS1221.8+2452, MS1407.9+5954, & MS2143.4+0704) reveal that each of these BL Lac objects is well-centered in an extended nebulosity that is consistent in brightness and morphology with being light from an elliptical galaxy at the previously reported redshift

Robert S. Thorne

I present a full leading-order calculation of F_2(x,Q^2) and F_L(x,Q^2), including contributions not only from leading order in α_s, but also from the leading power of α_s for each order in ln(1/x). The calculation is ordered according to the inputs and evolution of the structure functions, and the perturbative form of the inputs is determined. I compare the

K. E. Nagaev

The frequency dependence of shot noise in mesoscopic diffusive contacts is calculated with account taken of long-range Coulomb interaction and external screening. While the low-frequency noise is 1/3 of noise of classical Poisson process independently of the contact shape, the high-frequency noise tends to the full classical value for long and narrow contact

Soon-Tae Hong, Byung-Yoon Park, Dong-Pil Min

The strange magnetic form factor of proton is calculated in a model independent way to confirm the recent experimental result of the SAMPLE Collaboration. We consider a set of six inertia parameters to realize the magnetic moments of the baryon octet. We show that the strange form factor of proton is a positive quantity, i.e. +0.37 n.m.. Its positiveness is

A. G. Beda, E. V. Demidova, A. S. Starostin, M. B. Voloshin

We analyze the possibility of using a low-background Ge-NaI spectrometer in a reactor experiment for a search for neutrino magnetic moment down to $3 \times 10^{-11}$ of the electron magneton. The properties of the so-far existing Ge low-background spectrometers are discussed and additional sources of background in a reactor experiment at a small depth are e

Z. Slanic, D. P. Belanger

The specific heat critical behavior is measured and analyzed for a single crystal of the random-field Ising system Fe(0.93)Zn(0.07)F2 using pulsed heat and optical birefringence techniques. This high magnetic concentration sample does not exhibit the severe scattering hysteresis at low temperature seen in lower concentration samples and its behavior is there

J. A. de Azcarraga, A. J. Macfarlane, A. J. Mountain, J. C. Perez Bueno

The forms of the invariant primitive tensors for the simple Lie algebras A_l, B_l, C_l and D_l are investigated. A new family of symmetric invariant tensors is introduced using the non-trivial cocycles for the Lie algebra cohomology. For the A_l algebra it is explicitly shown that the generic forms of these tensors become zero except for the l primitive ones

A. Bassetto, D. Colferai, G. Nardelli

A rectangular Wilson loop with sides parallel to space and time directions is perturbatively evaluated in two light-cone gauge formulations of Yang-Mills theory in 1+1 dimensions, with ``instantaneous&#39;&#39; and ``causal&#39;&#39; interactions between static quarks. In the instantaneous formulation we get Abelian-like exponentiation of the area in terms o

J. Soffer, J. -M. Virey

A very promising spin physics programme will be soon on the way at the BNL Relativistic Heavy Ion Collider (RHIC). By studying the spin asymmetries for various processes (single photon, single-jet and $W^{\pm}$ production), we will compare the different predictions obtained using some sets of polarized parton distributions, available in the recent literature

J. L. Alonso, Ph. Boucaud, V. Martin-Mayor, A. J. van der Sijs

We present a relativistic spin-fermion model for the cuprates, in which both the charge and spin degrees of freedom are treated dynamically. The spin-charge coupling parameter is associated with the doping fraction. The model is able to account for the various phases of the cuprates and their properties, not only at low and intermediate doping but also for (

Riccardo Guida, Nicodemo Magnoli

In this letter we propose to use an extension of the variational approach known as Truncated Conformal Space to compute numerically the Vacuum Expectation Values of the operators of a conformal field theory perturbed by a relevant operator. As an example we estimate the VEV&#39;s of all (UV regular) primary operators of the Ising model and of some of the Tri

HEGRA-Collaboration, :, F. Aharonian et al

Between March 16, 1997 and April 14, 1997, a high flux level of TeV gamma-rays was observed from Mkn 501, using the HEGRA stereoscopic system of four imaging Cherenkov telescopes. The flux level varied during this period from about one half up to six times the flux observed from the Crab Nebula. Changes of the detection rate by a factor of up to 4 within 1 d

F. Yuasa, Y. Kurihara, S. Kawabata

The cross section of $e^+e^- \to b \bar{b} u \bar{d} μ^- \barν_μ$ process with a complete set of tree diagrams, 232 diagrams in the unitary gauge, was calculated at the energy range of $\sqrt{s}$ = 340 - 500 GeV by using GRACE system. A main contribution to the cross section comes from $t\bar{t}$ production, where $t$ and $\bar{t}$ decay into $bu\bar{d}$ and

T. Feldmann, P. Kroll

The eta_c-gamma transition form factor is calculated in a model based on a modified hard scattering approach to exclusive reactions, in which transverse degrees of freedom are taken into account. For the eta_c-meson a distribution amplitude of the Bauer-Stech-Wirbel type is used, where the two free parameters, namely the decay constant f(eta_c) and the trans

Jeong-Young Ji, Hyun-Hee Jung, Jong-Woong Park, Kwang-Sup Soh

We calculate the number of photons produced by the parametric resonance in a cavity with vibrating walls. We consider the case that the frequency of vibrating wall is $n ω_1 (n=1,2,3,...)$ which is a generalization of other works considering only $2 ω_1$, where $ω_1$ is the fundamental-mode frequency of the electromagnetic field in the cavity. For the calcul

Lov K. Grover

This paper shows that a quantum mechanical algorithm that can query information relating to multiple items of the database, can search a database in a single query (a query is defined as any question to the database to which the database has to return a (YES/NO) answer). A classical algorithm will be limited to the information theoretic bound of at least O(l

Adan Cabello, Jose M. Estebaranz, Guillermo Garcia Alcaine

We discuss two new demonstrations of the Bell-Kochen-Specker theorem: a state-independent proof using 14 four-dimensional propositions, based on a suggestion made by Clifton, and a state-specific proof involving 5 propositions on the singlet state of two spin-1/2 particles.

Adan Cabello, Jose M. Estebaranz, Guillermo Garcia Alcaine

We present a ``state-independent&#39;&#39; proof of the Bell-Kochen-Specker theorem using only 18 four-dimensional vectors, which is a record for this kind of proof. This set of vectors contains subsets which allow us to develop a ``state-specific&#39;&#39; proof with 10 vectors (also a record) and a ``probabilistic&#39;&#39; proof with 7 vectors which refle

M. A. Nielsen

We construct quantum mechanical observables and unitary operators which, if implemented in physical systems as measurements and dynamical evolutions, would contradict the Church-Turing thesis which lies at the foundation of computer science. We conclude that either the Church-Turing thesis needs revision, or that only restricted classes of observables may be

C. K. Fan, R. M. Green

We describe the cell structure of the affine Temperley-Lieb algebra with respect to a monomial basis. We construct a diagram calculus for this algebra.

Berengere Abou, Gilles Neron de Surgy, Jose-Eduardo Wesfreid

We have calculated the general dispersion relationship for surface waves on a ferrofluid layer of any thickness and viscosity, under the influence of a uniform vertical magnetic field. The amplification of these waves can induce an instability called peaks instability (Rosensweig instability). The expression of the dispersion relationship requires that the c

Giorgio Cattapan, Luciano Canton

In this paper we review the present status of the piNNN--NNN problem. In particular, we re-consider the chain-labelled approach recently proposed by us, and identify a class of graphs, previously overlooked, which prevents the kernel of the corresponding piNNN--NNN equations from being connected. We propose some pproximate schemes, yielding connected-kernel

Zhenping Li, Ye Hongxing, Lu Minghui

An unified approach to the pseudo scalar meson ($π, η$, and $K$) photoproduction off nucleons are presented. It begins with the low energy QCD Lagrangian, and the resonances in the s- and u- channels are treated in the framework of the quark model The duality hypothesis is imposed to limit the number of the t-channel exchanges. The CGLN amplitudes for each r

Luciano Canton, Wolfgang Schadow

The pd <--> pi+ t process has been calculated in the energy region around the Delta-resonance with elementary production/absorption mechanisms involving one and two nucleons. The isobar degrees of freedom have been explicitly included in the two-nucleon mechanism via pi-- and rho-exchange diagrams. No free parameters have been employed in the analysis since

Munshi Golam Mustafa, A. Ansari

Considering the confinement of massless $u$ and $d$ quarks and massive $s$ quarks in an axially symmetric quadrupole shaped deformable bag, the stability properties of color-singlet strangelets at finite temperatures are studied for the baryon number $A \leq$ 100. It is found that, in general, at each $A$ the energy of the strangelet is the lowest for the sp

Alejandro Adem, James F. Davis

This paper surveys some results and methods in topological transformation groups.

Nathan Berkovits

The free action for the massless sector of the Type II superstring was recently constructed using closed RNS superstring field theory. The supersymmetry transformations of this action are shown to satisfy an N=2 D=10 SUSY algebra with Ramond-Ramond central charges.

Martin Rivas

Since the spin of real particles is of order of $\hbar$, it is difficult to distinguish in a quantum mechanical experiment involving spinning particles what part of the outcome is related to the spin contribution and what part is a pure quantum mechanical effect. We analyze in detail a classical model of a nonrelativistic spinning particle under the action o

M. Welling

In this paper we consider space-times containing matter expanding or contracting according to a time-dependent scale factor. Cosmologies with vanishing, positive or negative cosmological constant are considered. In the case of vanishing or negative cosmological constant open and closed spatial surfaces are solutions while in the case of positive cosmological

Mariusz P. Dabrowski, Arne L. Larsen

The string equations of motion for some homogeneous (Kantowski-Sachs, Bianchi I and Bianchi IX) background spacetimes are given, and solved explicitly in some simple cases. This is motivated by the recent developments in string cosmology, where it has been shown that, under certain circumstances, such spacetimes appear as string-vacua. Both tensile and null

Yong-Wan Kim, K. D. Rothe

Following systematically the generalized Hamiltonian approach of Batalin, Fradkin and Tyutin, we embed the second-class non-abelian self-dual model of P. K. Townsend et al into a gauge theory. The strongly involutive Hamiltonian and constraints are obtained as an infinite power series in the auxiliary fields. By formally summing the series we obtain a simple

Rainer Mueller

We study how the decay properties of particles are changed by acceleration. It is shown that under the influence of acceleration (1) the lifetime of particles is modified and (2) new processes (like the decay of the proton) become possible. This is illustrated by considering scalar models for the decay of muons, pions, and protons. We discuss the close conce

Hongsu Kim

As a system which is known to admit classical wormhole instanton solutions, Einstein-Kalb-Ramond (KR) antisymmetric tensor theory is revisited. As an untouched issue, the existence of fermionic zero modes in the background of classical axionic wormhole spacetime and its physical implications is addressed. In particular, in the context of a minisuperspace qua

Paul H. Frampton

In this talk I begin with some general discussion of model building in particle theory, emphasizing the need for motivation and testability. Three illustrative examples are then described. The first is the Left-Right model which provides an explanation for the chirality of quarks and leptons. The second is the 331-model which offers a first step to understan

Stanley J. Brodsky

The ensemble of light-cone Fock wavefunctions $\{ψ_{n/H}(x_i,\vec k_{\perp i},λ_i)\}$ provides a conceptual basis for representing physical hadrons and nuclei in terms of their fundamental quark and gluon degrees of freedom. A number of applications of the light-cone formalism to QCD phenomenology are briefly reviewed, such as the origin of Regge behavior of

Markus A. Luty

In strongly-coupled theories with no small parameters, there are factors of 4πthat appear when the couplings of the low-energy effective lagrangian are written in units of the effective cutoff Λ. These numerical factors can be explained using &#34;naive dimensional analysis.&#34; We extend these ideas to supersymmetric theories, and show how to systematicall

Guy D. Moore

I discuss the applicability of classical techniques to the study of the dynamics of infrared, bosonic fields at the electroweak phase transition. I present the lattice as a natural means of cutting off hard, nonclassical modes, and discuss the problem of integrating out the excluded modes perturbatively. I then apply the classical lattice technique to study

C. J. Maxwell

We consider the structure of the leading ultra-violet (UV) renormalon singularity associated with the QCD vacuum polarization Adler D-function, in the approximation that only planar Feynman diagrams are retained. This ``planar approximation&#39;&#39; results in some simplifications, in particular three of the four potential contributions from four-fermion op

G. L. Fogli, E. Lisi, D. Montanino, G. Scioscia

The present possible evidences in favor of neutrino masses and mixings from solar, atmospheric, and accelerator experiments cannot be all reconciled in a three-family framework, unless some data are excluded. We grade all possible three-family scenarios according to their compatibility with the available data. A recently proposed scenario appears to emerge n

G. L. Fogli, E. Lisi, D. Montanino

Solar neutrino oscillations with wavelengths comparable to the Earth-Sun distance provide a viable explanations of the long-standing solar neutrino deficit. They imply a time-dependent modulation of the solar neutrino flux due to the eccentricity of the Earth orbit. Motivated by this testable prediction, we propose a Fourier analysis of the signal observable

Andrzej Czarnecki, Kirill Melnikov

We have recently presented the complete O(alpha_s^2) corrections to the semileptonic decay width of the b quark at maximal recoil. Here we discuss various technical aspects of that calculation and further applications of similar methods. In particular, we describe an expansion which facilitates the phase space integrations and the treatment of the mixed real

Minos Axenides, Leandros Perivolaropoulos

We review recent work on a new class of topological defects which possess a nonsymmetric core. They arise in scalar field theories with global symmetries, U(1) for domain walls and SU(2) for vortices, which are explicitly broken to $Z_2$ and U(1) respectively. Both of the latter symmetries are spontaneously broken. For a particular range of parameters both t

B. Bajc, S. Fajfer R. J. Oakes, S. Prelovšek

We analyze $D \to P V$, $D \to PP$ and $D \to VV$ decays within a model developed to describe the semileptonic decays $D \to V l ν_l$ and $D\to P l ν_l$. This model combines the heavy quark effective Lagrangian and chiral perturbation theory. We determine amplitudes for decays in which the direct weak annihilation of the initial $D$ meson is absent or neglig

T. Kurimoto, A. Tomita

We have analyzed how much the $CP$ angles to be measured at B factories can deviate from the geometrical ones defined in unitarity triangle under the existence of new physics. The measurements are given in rephasing invariant form. If KM matrix is not a $3\times 3$ and unitary matrix, $\tildeϕ_1$ and $\tildeϕ_3$ is affected, and the value of $\tildeϕ_3$ depe

T. Kurimoto

The measurement and precision at B physics experiment are reviewed by taking into account of the numbers of B mesons to be produced in the future experimental projects. With $10^9$ or more B mesons we will be able to fix the parameters in Kobayashi-Maskawa matrix elements or find a signal of new physics.

Paul H. Frampton

In this review there is first a survey of the HERA data. Then we discuss the theory response including querying the consistency of the data, compositeness, contact terms, and leptoquarks including as a special case the R symmetry violating squark. The SU(15) possibility for a light leptoquark is mentioned. Finally there is a summary.

CLEO Collaboration, T. Browder et al

We have searched for the rare decay of the eta meson $η\to e^{+}e^{-}$ using the CLEO II detector. The $η$&#39;s were produced in $e^{+}e^{-}$ collisions with 10 GeV center-of-mass energy at the Cornell Electron Storage Ring (CESR). We find with 90% confidence the upper limit on the branching fraction $B(η\to e^{+}e^{-}) < 7.7\times 10^{-5}$. The application

Stefan Soldner-Rembold

A search for a first generation scalar leptoquark (LQ) has been performed using the data collected by the OPAL detector in 1996 at e+e- centre-of-mass energies sqrt{s} of 161 and 172 GeV. It is assumed that a single leptoquark can be produced in the process eq->LQ, where the initial state quark originates from a hadronic fluctuation of a quasi-real photon wh

Shawn J. Kolitch, Douglas M. Eardley

This paper studies the decay of a large, closed domain wall in a closed universe. Such walls can form in the presence of a broken, discrete symmetry. We introduce a novel process of quantum decay for such a wall, in which the vacuum fluctuates from one discrete state to another throughout one half of the universe, so that the wall decays into pure field ener

Nils Andersson, Kostas D. Kokkotas

We present the results of a numerical study of the fluid $f$, $p$ and the gravitational $w$ modes for increasingly relativistic nonrotating polytropes. The results for $f$ and $w$-modes are in good agreement with previous data for uniform density stars, which supports an understanding of the nature of the gravitational wave modes based on the uniform density

F. W. Hehl, A. Macías, E. W. Mielke, Yu. N. Obukhov

We consider a classical Dirac field in flat Minkowski spacetime. We perform a Gordon decomposition of its canonical energy-momentum and spin currents, respectively. Thereby we find for each of these currents a convective and a polarization piece. The polarization pieces can be expressed as exterior covariant derivatives of the two-forms $\check M_α$ and $M_{

S. Massar, R. Parentani

The aim of this paper is to compute transitions amplitudes in quantum cosmology, and in particular pair creation amplitudes and radiative transitions. To this end, we apply a double adiabatic development to the solutions of the Wheeler-DeWitt equation restricted to mini-superspace wherein gravity is described by the scale factor $a$. The first development co

G. Amelino-Camelia

Some of the recent work on quantum gravity has involved modified uncertainty relations such that the products of the uncertainties of certain pairs of observables increase with time. It is here observed that this type of modified uncertainty relations would lead to quantum decoherence, which could explain the classical behavior of macroscopic systems, and CP

Z. Slanic, D. P. Belanger, J. A. Fernandez-Baca

The high magnetic concentration Ising antiferromagnet Fe(0.93)Zn(0.07)F2 does not exhibit the severe critical scattering hysteresis at low temperatures observed in all lower concentration samples studied. The system therefore provides equilibrium neutron scattering line shapes suitable for determining random-field Ising model critical behavior.

Andrea Cavagna, Irene Giardina, Giorgio Parisi

We study the geometrical structure of the states in the low temperature phase of a mean field model for generalized spin glasses, the p-spin spherical model. This structure cannot be revealed by the standard methods, mainly due to the presence of an exponentially high number of states, each one having a vanishing weight in the thermodynamic limit. Performing

Louis Taillefer, Benoit Lussier, Robert Gagnon, Kamran Behnia

The thermal conductivity of YBa_2Cu_3O_6.9 was measured at low temperatures in untwinned single crystals with concentrations of Zn impurities from 0 to 3% of Cu. A linear term kappa_0/T = 0.19 mW/K^2.cm is clearly resolved as T -> 0, and found to be virtually independent of Zn concentration. The existence of this residual normal fluid strongly validates the

Yanhui Liu, Pierre Cizeau, Martin Meyer, Chung-Kang Peng

The correlation function of a financial index of the New York stock exchange, the S&P 500, is analyzed at 1 min intervals over the 13-year period, Jan 84 -- Dec 96. We quantify the correlations of the absolute values of the index increment. We find that these correlations can be described by two different power laws with a crossover time t_\times\approx 600

T. P. C. van Noije, M. H. Ernst

The dynamics of inelastic hard spheres is described in terms of the binary collision expansion, yielding the corresponding pseudo-Liouville equation and BBGKY hierarchy for the reduced distribution functions. Based on cluster expansion techniques we derive the Boltzmann and ring kinetic equations for inelastic hard spheres. In the simple ring approximation,

Stéphane Belin, Kamran Behnia

We report on the first measurements of thermal conductivity in the superconducting state of (TMTSF)_2ClO_4. The electronic contribution to heat transport is found to decrease rapidly below T_c, indicating the absence of low-energy electronic excitations. We argue that this result provides strong evidence for a nodeless superconducting gap function but does n

Yu-Liang Liu

We study a finite quantum wire connected to external leads, and show that the conductance of the system significantly depends upon the length of the quantum wire and the position of the impurity in it. For a very long quantum wire and the impurity far away from its two ends, the conductance has the same behavior as that for an infinity quantum wire above som

Yu-Liang Liu

Using the bosonization technique, we have studied a spin-1/2 magnetic impurity in Heisenberg chain, and shown that the impurity specific heat and spin susceptibility have an anomalous temperature dependence.

Stefano Lepri, Antonio Politi, Alessandro Torcini

According to a previous conjecture, spatial and temporal Lyapunov exponents of chaotic extended systems can be obtained from derivatives of a suitable function: the entropy potential. The validity and the consequences of this hypothesis are explored in detail. The numerical investigation of a continuous-time model provides a further confirmation to the exist

S. Louies, L. Brenig

The general term of the Poincare normalizing series is explicitly constructed for non-resonant systems of ODE&#39;s in a large class of equations. In the resonant case, a non-local transformation is found, which exactly linearizes the ODE&#39;s and whose series expansion always converges in a finite domain. Examples are treated.

D. W. Messinger, D. C. B. Whittet, W. G. Roberge

We use polarimetric observations of two stars (HD29647, HD283809) in the general direction of TMC-1 in the Taurus Dark Cloud to investigate grain properties and cloud structure in this region. We show the data to be consistent with a simple two-component model, in which general interstellar polarization in the Taurus Cloud is produced by a widely distributed

Chris Fryer, Vassiliki Kalogera

We study the four double neutron star systems found in the Galactic disk in terms of the orbital characteristics of their immediate progenitors and the natal kicks imparted to neutron stars. Analysis of the effect of the second supernova explosion on the orbital dynamics, combined with recent results from simulations of rapid accretion onto neutron stars lea