November 1996 arXiv papers — page 15

Sergey Alekhin

We have performed the NLO QCD global fit of BCDMS, NMC, H1 and ZEUS data with full account of point-to-point correlations using the Bayesian approach to the treatment of systematic errors. Parton distributions in the proton associated with experimental uncertainties, including both statistical and systematic ones were obtained. The gluon distribution in the

Toshio Tsukamoto

We present a study of single-W production ($\eetoenuW$) as a new probe of the anomalous couplings at the LEP energy region. The cross-section measurement of the single-W process is found to give complementary bounds on the anomalous couplings to those obtained from W-pair analysis at LEP2.

Mikulas Gintner, Stephen Godfrey, Gilles Couture

We studied the sensitivity of the process $e^+e^-\to \ell νq\bar{q}'$ to anomalous trilinear gauge boson couplings of the $WWγ$ and WWZ vertices at the center of mass energies $\sqrt{s}=500$ GeV and 1 TeV. The bounds for the couplings we obtained result from an analysis of a five dimensional angular differential cross section. In our calculations we incl

G. I. Smirnov

It is shown that the latest results from NMC and E665 on the $F_2^A(x)/F_2^{D}(x)$ obtained in the shadowing region, bring new evidence of the universal $A$ -- dependence of distorsions of a free nucleon structure function by nuclear medium. The universality holds in the entire $x$ -range and can be explained as a saturation of the distortions of the parton

H. G. Ballesteros, J. M. Carmona, L. A. Fernandez, V. Martin-Mayor

We study the antiferromagnetic RP(2) model in four dimensions. We find a second order transition with two order parameters, one ferromagnetic and the other antiferromagnetic. The antiferromagnetic sector has mean-field critical exponents and a renormalized coupling which goes to zero in the continuum limit. The exponents of the ferromagnetic channel are not

D. Shahar, D. C. Tsui, M. Shayegan, E. Shimshoni

We demonstrate experimentally that the transitions between adjacent integer quantum Hall (QH) states are equivalent to a QH-to-insulator transition occurring in the top Landau level, in the presence of an inert background of the other completely filled Landau levels, each contributing a single unit of quantum conductance, $e^{2}/h$, to the total Hall conduct

Neil Trentham

We report the discovery of a candidate supernova in the ultraluminous galaxy IRAS 12112+0305 during April/May 1995. This would be the first supernova discovered in an ultraluminous galaxy with L_IR > 10^12 L_sun, although supernovae have been discovered in the slightly less extreme starburst galaxy NGC 3690. If this is a supernova, our very limited observati

Insu Yi, Ramesh Narayan

High Li abundances have been reported in the late type secondaries of five soft X-ray transients (SXTs), V404 Cyg, A0620-00, GS2000+25, Nova Mus 1991, and Cen X-4. Since Li is likely to be depleted in stars of this type, the origin of the Li is puzzling. Li has not been seen in similar secondaries of cataclysmic variables, which suggests that the high Li abu

Vyjayanthi Chari, Andrew Pressley

We classify the irreducible finite-dimensional representations of the twisted quantum affine algebras.

Paolo Ciafaloni, Alessandro Strumia

After a general discussion about the quantitative meaning of the naturalness upper bounds on the masses of supersymmetric particles, we compute these bounds in models with gauge-mediated soft terms. We find interesting upper limits on the right-handed slepton masses that, unless the messenger fields are very light, disfavor minimal models with large messenge

Alan Dressler, Ian Smail

The ``MORPHS&#39;&#39; group has completed the cataloging, parameterization, and morphological classification of ~2000 galaxies in 10 rich clusters from 0.36 < z < 0.56. From a weak lensing analysis using these data, which compares the X-ray properties (L_X) of the clusters with virial temperature estimates (T_v) from the lensing shear strength, we find litt

E. M. Rains

In a recent paper [quant-ph/9610040], Shor and Laflamme define two ``weight enumerators&#39;&#39; for quantum error correcting codes, connected by a MacWilliams transform, and use them to give a linear-programming bound for quantum codes. We extend their work by introducing another enumerator, based on the classical theory of shadow codes, that tightens thei

R. Ketzmerick, K. Kruse, S. Kraut, T. Geisel

The multifractal dimensions D2^mu and D2^psi of the energy spectrum and eigenfunctions, resp., are shown to determine the asymptotic scaling of the width of a spreading wave packet. For systems where the shape of the wave packet is preserved the k-th moment increases as t^(k*beta) with beta=D2^mu/D2^psi, while in general t^(k*beta) is an optimal lower bound.

Alok Kumar, Cumrun Vafa

We use non-perturbative U-duality symmetries of type II strings to construct new vacuum solutions. In some ways this generalizes the F-theory vacuum constructions. We find the possibilities of new vacuum constructions are very limited. Among them we construct new theories with N=2 supersymmetry in 3-dimensions and (1, 1) supersymmetry in 2-dimensions.

A. V. Razumov, M. V. Saveliev

Some special solutions to the multidimensional Lamé and Bourlet type equations are constructed in an explicit form.

Nicolas Gisin, Todd A. Brun, Marco Rigo

Quantum mechanics is nonlocal. Classical mechanics is local. Consequently classical mechanics can not explain all quantum phenomena. Conversely, it is cumbersome to use quantum mechanics to describe classical phenomena. Not only are the computations more complex, but - and this is the main point - it is conceptually more difficult: one has to argue that nonl

K. Heinemann

This work is devoted to an examination of Stern-Gerlach forces consistent with special relativity and is motivated by recent interest in the relativistic Stern-Gerlach force acting on polarized protons in high-energy particle accelerators. The equations for the orbital and spin motion of a classical charged particle with arbitrary intrinsic magnetic dipole m

D. Kiderlen, P. Danielewicz

Generalization of Gaussian trial wave functions in quantum molecular dynamics models is introduced, which allows for long-range correlations characteristic for composite nuclear fragments. We demonstrate a significant improvement in the description of light fragments with correlations. Utilizing either type of Gaussian wave functions, with or without correla

A. Ohnishi, J. Randrup

Multifragmentation in Au+Au collisions is investigated at incident energies in the range 100-400 MeV per nucleon by means of a recently developed quantal Langevin model. The inclusion of quantum fluctuations enhances the average multiplicity of intermediate mass fragments, especially in central collisions. This is mainly because the excitation energies of fr

V. G. J. Stoks, Th. A. Rijken

We present a chiral-invariant meson-baryon Lagrangian which describes the interactions of the baryon octet with the lowest-mass meson nonets. The nonlinear realization of the chiral symmetry generates pair-meson interaction vertices. The corresponding pair-meson coupling constants can all be expressed in terms of the meson-nucleon-nucleon pseudovector, scala

M. Sander, H. V. von Geramb

Two-body interactions of elementary particles are useful in particle and nuclear physics to describe qualitatively and quantitatively few- and many-body systems. We are extending for this purpose the quantum inversion approach for systems consisting of nucleons and mesons. From the wide range of experimentally studied two-body systems we concentrate here on

Ken Ono, Christopher Skinner

For each prime $\ell$, let $|\cdot|_\ell$ be an extension to $\bar \Q$ of the usual $\ell$-adic absolute value on $\Q$. Suppose $g(z) = \sum_{n=0}^\infty c(n)q^n \in M_{k+\half}(N)$ is an eigenform whose Fourier coefficients are algebraic integers. Under a mild condition, for all but finitely many primes $\ell$ there are infinitely many square-free integers

Peter W. Michor

The geodesic flow on the tangent bundle is the flow of a certain vector field which is called the spray $S:TM\to TTM$. The flow lines of the vector field $\ka_{TM}øTS:TTM\to TTTM$ project to the Jacobi fields on $TM$. This could be called the Jacobi flow.

Andreas Kriegl, Peter W. Michor

The theory of product preserving functors and Weil functors is partly extended to infinite dimensional manifolds, using the theory of $C^\infty$-algebras.

Alexander V. Isaev, Steven G. Krantz

We give an explicit description of hyperbolic Reinhardt domains D in C^2 such that: (i) D has C^k-smooth boundary for some k greater than or equal to 1, (ii) D intersects at least one of the coordinate complex lines $\{z_1=0\}$, $\{z_2=0\}$, and (iii) D has noncompact automorphism group. We also give an example that explains why such a setting is natural for

H. Babujian, M. Karowski, A. Zapletal

A system of U(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz. The highest weight property of the solutions is proved and some examples of solutions are calculated explicitly. (Part II of a series of articles on the generalized nested Bethe Ansatz and difference equations.)

H. Babujian, M. Karowski, A. Zapletal

A system of SU(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz, also called &#34;off shell&#34; Bethe Ansatz. The highest weight property of the solutions is proved. (Part I of a series of articles on the generalized nested Bethe Ansatz and difference equations.)

O. M. Del Cima, D. H. T. Franco, J. A. Helayël-Neto, O. Piguet

In this letter the algebraic renormalization method, which is independent of any kind of regularization scheme, is presented for the parity-preserving QED_3 coupled to scalar matter in the broken regime, where the scalar assumes a finite vacuum expectation value, $<\vf> = v$. The model shows to be stable under radiative corrections and anomaly free.

O. M. Del Cima, D. H. T. Franco, J. A. Helayël-Neto, O. Piguet

In this letter the algebraic renormalization method, which is independent of any kind of regularization scheme, is presented for the parity-preserving QED_3 coupled to scalar matter in the symmetric regime, where the scalar assumes vanishing vacuum expectation value, $<ϕ>=0$. The model shows to be stable under radiative corrections and anomaly free.

Martin J. Savage, James Walden

We examine the effects of SU(3) breaking in the matrix elements of the flavour-diagonal axial currents between octet baryon states and find that SU(3) breaking may be substantial for some matrix elements. We estimate the strange axial matrix element in the proton to be between -0.35 and 0 and the matrix element of the flavour-singlet current in the proton to

Ali Abbasabadi, David Bowser-Chao, Duane A. Dicus, Wayne W. Repko

Higgs boson radiative decays of the form $H\rightarrow f\bar{f}γ$ are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present $e\bar{e}$ invariant mass distributions for $H\rightarrow e\bar{e}γ$, which illustrate the import

John Ellis

This talk reviews some of the hot topics in spin physics and related subjects, including perturbative QCD predictions for polarized parton distributions and their possible behaviours at small x, the Bjorken and singlet sum rules and the treatment of higher orders in perturbative QCD, different interpretations of the EMC spin effect including chiral solitons

Pervez Hoodbhoy

Diffractive production of J/Psi particles by virtual photons on a proton target is studied with a view towards understanding two important corrections to the leading order result. First, the effect of Fermi motion of the heavy quarks is studied by performing a systematic expansion in the relative velocity, and a simple correction factor is derived. This is c

Robert D. Pisarski, Michel Tytgat

Consider the effective lagrangian for pions in the chiral limit, computed to leading order in an expansion about zero temperature. To describe the scattering of pions with small momenta, it is necessary to include not just the usual shift in the pion decay constant, but also a new, nonlocal term, which is precisely analogous to the hard thermal loops of hot

R. Engel, A. Rostovtsev

The possibility to measure diffraction dissociation in collisions of real and virtual photons at LEP2 is pointed out.

Seung Woo Ham, Sun Kun Oh, Bjong Ro Kim

We derive analytic formulas for the radiatively corrected mass of the scalar Higgs boson in the framework of the minimal supersymmetric standard model (MSSM). Since the scalar-top-quark mass in our analysis include terms proportional to the gauge couplings in the 1-loop effective potential, the radiatively corrected mass of the scalar Higgs boson partially c

J. Giedt, J. Greensite

We introduce a gauge-invariant measure of the local &#34;abelianicity&#34; of any given lattice configuration in non-abelian lattice gauge theory; it is essentially a comparison of the magnitude of field strength commutators to the magnitude of the field strength itself. This measure, in conjunction with the cooling technique, is used to probe the SU(2) latt

Fermilab E791 Collaboration, E. M. Aitala et al

We report a measurement of the branching ratio B(D+-->rho^0 l nu)/ B(D+-->K*0 l nu) from the Fermilab charm hadroproduction experiment E791. Based on signals of 49+-17 events in the D+--> rho^0 e nu mode and 54+-18 events in the D+--> rho^0 mu nu mode, we measure B(D+-->rho^0 e nu)/B(D+-->K*0 e nu) = 0.045+-0.014+-0.009, and B(D+-->rho^0 mu nu)/B(D+-->K*0 mu

S. Gadomski, P. Eerola, A. V. Bannikov

Previous results for the prospects of B_s mixing measurement in the ATLAS experiment at LHC are updated. The improved analysis method of the studied decay channels B_s -> D_s pi and B_s -> D_s a_1, combined with most recent values for the branching ratios and the B_s lifetime, leads to the new ATLAS sensitivity range for the x_s measurement: x_s^{max} = 42.

G W Gibbons

I describe how the states of a discrete automata with p sites, each of which may be off or on, can be represented as Majorana spinors associated to a spacetime with signature (p,p). Some ideas about the quantization of such systems are discussed and the relationship to some unconventional formulations and generalizations of quantum mechanics, particularly Jo

R. A Helzerman, M. P. Harper

This paper describes an extension to the constraint satisfaction problem (CSP) called MUSE CSP (MUltiply SEgmented Constraint Satisfaction Problem). This extension is especially useful for those problems which segment into multiple sets of partially shared variables. Such problems arise naturally in signal processing applications including computer vision, s

J. M. Harris, Z. -X. Shen, P. J. White, D. S. Marshall

We report angle-resolved photoemission spectroscopy measurements of the excitation gap in underdoped superconducting thin films of Bi_2Sr_2Ca_{1-x}Dy_xCu_2O_{8+d}. As Tc is reduced by a factor of 2 by underdoping, the superconducting state gap Δdoes not fall proportionally, but instead stays constant or increases slightly, in violation of the BCS mean-field

M. S. L. du Croo de Jongh, P. J. H. Denteneer

We calculate the spin stiffness of the S=1/2 frustrated Heisenberg antiferromagnet directly from a general formula which is evaluated in the Schwinger boson mean-field approximation. Both Néel and collinear ordering are considered. For collinear ordering, we take the anisotropy of this phase into account, unlike previous approaches. For Néel ordering, a deta

B. Partoens, F. M. Peeters

The ring configurations for classical two-dimensional atoms are calculated within the Thomson model and compared with the results from `exact&#39; numerical simulations. The influence of the functional form of the confinement potential and the repulsive interaction potential between the particles on the configurations is investigated. We also give exact resu

X. Zotos, F. Naef, P. Prelovsek

We study the lowest order conservation laws in one-dimensional (1D) integrable quantum many-body models (IQM) as the Heisenberg spin 1/2 chain, the Hubbard and t-J model. We show that the energy current is closely related to the first conservation law in these models and therefore the thermal transport coefficients are anomalous. Using an inequality on the t

Ken Sekimoto

Several stochastic models called thermal ratchet models have been recently proposed to analyze the motor proteins such as myosin and kinesin,etc. We propose a method to study the energetics of those models, and show how the rate of energy consumption and the energy dissipation are evaluated. As a demonstration we consider &#34;Feynman&#39;s ratchet&#34;, a t

H. Westfahl, A. H. Castro Neto, A. O. Caldeira

In this work we introduce a bosonization scheme for the low energy excitations of a 2D interacting electron gas in the presence of an uniform magnetic field under conditions where a large integral number of Landau levels are filled. We give an explicit construction for the electron operator in terms of the bosons. We show that the elementary neutral excitati

T. Kottos, G. P. Tsironis, F. M. Izrailev

Transport properties of one-dimensional Kronig-Penney models with binary correlated disorder are analyzed using an approach based on classical Hamiltonian maps. In this method, extended states correspond to bound trajectories in the phase space of a parametrically excited linear oscillator, while the on site-potential of the original model is transformed to

M. Stopa, J. P. Bird

Self-consistent electronic structure calculations, for devices recently fabricated and studied by Zhitenev et al. for capacitance spectroscopy in the quantum Hall regime, demonstrate that reproducible resonances in the coupling between adiabatically free edge states and isolated ``puddles&#39;&#39; of electrons of higher filling factor under the gate proceed

V. I. Belinicher, A. L. Chernyshev, V. A. Shubin

The t-J model in the spinless-fermion representation is studied. An effective Hamiltonian for the quasiparticles is derived using canonical transformation approach. It is shown that the rather simple form of the transformation generator allows to take into account effect of hole interaction with the short-range spin waves and to describe the single-hole grou

Thomas A. Barlow, W. L. W. Sargent

We present results from Keck I high resolution spectroscopy of the radio loud quasar PKS 0123+257 ($z_e$=2.364, V=17.5). In this object we detect Ly$α$, N V 1238,1242, Si IV 1393,1402, and C IV 1548,1550 in an absorption system at a redshift of 2.369. The Ly$α$ line has a square- bottomed profile suggesting a high column density of gas, yet the line does not

R. A. Bell, M. L. Houdashelt

We present the first results from our population synthesis models of elliptical galaxies. In this paper, we concentrate upon the optical region of the spectrum (3000-7000 A). We model elliptical galaxies as coeval, single-metallicity stellar populations. Integrated spectra are constructed from synthetic spectra of the stars which lie along 6, 10 and 16 Gyr i

M. L. Houdashelt, R. A. Bell

We present the first results from our population synthesis models of elliptical galaxies. In this paper, we concentrate upon the near-infrared region of the spectrum (0.7-3 um). We model elliptical galaxies as coeval, single-metallicity stellar populations. Integrated spectra are constructed from synthetic spectra of the stars which lie along 6, 10 and 16 Gy

Pawan Kumar, Eliot J. Quataert

We calculate the excitation of low frequency gravity waves by turbulent convection in the sun and the effect of the angular momentum carried by these waves on the rotation profile of the sun&#39;s radiative interior. We find that the gravity waves generated by convection in the sun provide a very efficient means of coupling the rotation in the radiative inte

Pawan Kumar, Eliot J. Quataert

Recent observations of PSR J0045-7319, a radio pulsar in a close eccentric orbit with a massive B-star companion, indicate that the system&#39;s orbital period is decreasing on a timescale of $\approx 5 \times10^{5}$ years, which is much shorter than the timescale of $\approx$ 10^9 years given by the standard theory of tidal dissipation in radiative stars. O

Roelof S. de Jong

FITS images in the B, V, R, I, H and K passbands are presented of a sample of 86 face-on spiral galaxies. The galaxies were selected from the UGC to have a diameter of at least 2 arcmin and a minor over major axis ratio larger than 0.625. The selected galaxies have an absolute Galactic latitude |b|>25 degree, to minimize the effect of Galactic extinction and

Avery Meiksin

The Gunn-Peterson effect, absorption of Lya photons by a homogeneous component of the intergalactic medium (IGM), potentially provides a test of Big Bang Nucleosynthesis (BBN). With a lower limit on the UV radiation field estimated from the contribution due to QSOs, a measurement of the Lya opacity of the intergalactic medium would permit the derivation of a

Nelson Caldwell, James Rose

We present multi-fiber spectroscopy and broadband imaging of early-type galaxies in five nearby rich clusters of galaxies. The main purpose was to look for ``abnormal'' spectrum galaxies (i.e., post-starburst galaxies which have strong Balmer absorption lines and emission line galaxies) in nearby clusters that are similar to those found by Caldwell et al. (1

Ian Smail, Richard S. Ellis, Alan Dressler, Warrick J. Couch

We present weak lensing results for 12 distant clusters determined from images obtained with the refurbished HST. We detect the signature of gravitational lensing in 11 of the 12 clusters; the clusters span nearly an order of magnitude in lensing strength. The sample thus provides an excellent database for correlating direct mass estimates from lensing with

Terence Gaffney, Robert Gassler

We define the Segre numbers of an ideal as a generalization of the multiplicity of an ideal of finite colength. We prove generalizations of various theorems involving the multiplicity of an ideal such as a principle of specialization of integral dependence, the Rees-Böger theorem, and the formula for the multiplicity of the product of two ideals. These resul

Andreas Matuschke

We consider a compact twistor space P and assume that there is a surface S in P, which has degree one on twistor fibres and contains a twistor fibre F, e.g. P a LeBrun twistor space. Similar to Donaldson and Buchdahl we examine the restriction of an instanton bundle V equipped with a fixed trivialisation along F to a framed vector bundle over (S,F). First we

Shinya Watanabe, James W. Swift

A mystery surrounds the stability properties of the splay-phase periodic solutions to a series array of N Josephson junction oscillators. Contrary to what one would expect from dynamical systems theory, the splay state appears to be neutrally stable for a wide range of system parameters. It has been explained why the splay state must be neutrally stable when