June 2001 arXiv papers — page 11

Brandon P. van Zyl, R. K. Bhaduri, Justin Sigetich

We investigate the behavior of a dilute quasi two-dimensional, harmonically confined, weakly interacting Bose gas within the finite-temperature Thomas-Fermi approximation. We find that the thermodynamic properties of the system are markedly different for repulsive and attractive interactions. Specifically, in contrast to the repulsive case, there appears to

Andre Lukas, David Skinner

In the context of a five-dimensional brane-world model motivated from heterotic M-theory, we develop a framework for potential-driven brane-world inflation. Specifically this involves a classification of the various background solutions of (A)dS_5 type, an analysis of five-dimensional slow-roll conditions and a study of how a transition to the flat vacuum st

Adi Armoni, Rodolfo Russo

We discuss the issue of the cosmological constant in non-commutative non-supersymmetric gauge theories. In particular, in orbifold field theories non-commutativity acts as a UV cut-off. We suggest that in these theories quantum corrections give rise to a vacuum energy ρ, that is controlled by the non-commutativity parameter θ, ρ~ 1/theta^2 (only a soft logar

Jonathan Mackey, Martin White, Marc Kamionkowski

It has recently been argued that the observed ellipticities of galaxies may be determined at least in part by the primordial tidal gravitational field in which the galaxy formed. Long-range correlations in the tidal field could thus lead to an ellipticity-ellipticity correlation for widely separated galaxies. We present a new model relating ellipticity to an

Di Qing, Ivan Schmidt

The photo-production of nucleon resonances is calculated based on a chiral constituent quark model including both relativistic corrections H{rel} and two-body exchange currents, and it is shown that these effects play an important role. We also calculate the first moment of the nucleon spin structure function g1 (x,Q^2) in the resonance region, and obtain a

Michael T. Anderson

A large class of vacuum space-times is constructed in dimension 4+1 from hyperboloidal initial data sets which are not small perturbations of empty space data. These space-times are future geodesically complete, smooth up to their future null infinity, and extend as vacuum space-times through their Cauchy horizon. Dimensional reduction gives non-vacuum space

G. Barnich, M. Grigoriev, M. Henneaux

Noncommutative versions of theories with a gauge freedom define (when they exist) consistent deformations of their commutative counterparts. General aspects of Seiberg-Witten maps are discussed from this point of view. In particular, the existence of the Seiberg-Witten maps for various noncommutative theories is related to known cohomological theorems on the

Eef van Beveren, George Rupp

A general expression resembling Breit-Wigner formulae is derived for the description of resonances which appear in meson-meson scattering. Starting point is a unitarised meson model, but reduced to a simpler form and freed from the specific assumption about the confining force. The parameters of the resulting ``Resonance-Spectrum Expansion'' are directly rel

Alice Shapley, G. Fabbiano, P. B. Eskridge

We have performed a multiparametric analysis of luminosity data for a sample of 234 normal spiral and irregular galaxies observed in X-rays with the {\it Einstein Observatory}. This sample is representative of S and Irr galaxies, with a good coverage of morphological types and absolute magnitudes. In addition to X-ray and optical da ta, we have compiled H-ba

Harald Ita, Yaron Oz

We use boundary string field theory to study open string tachyon condensation on a three-sphere closed string background. We consider the closed string background described by $SU(2)_k$ WZW model in the limit of large $k$. We compute the exact tachyon potential and analyse the decay modes.

Xiao-Gang He, Jenq-Yuan Leou, Jian-Qing Shi

In low energy SUSY theories exchange of gluino and squark with left-right mixing can produce a large gluonic dipole interaction. In this paper we study the effects of this interaction on $B\to K π$ using QCD improved factorization method. The Standard Model predicts a smaller branching ratio for $B^0 \to \bar K^0 π^0$ than experimental measured one. We find

Luigi Del Debbio, Haralambos Panagopoulos, Paolo Rossi, Ettore Vicari

In the context of four-dimensional SU(N) gauge theories, we study the spectrum of the confining strings. We compute, for the SU(6) gauge theory formulated on a lattice, the three independent string tensions sigma_k related to sources with Z_N charge k=1,2,3, using Monte Carlo simulations. Our results, whose uncertainty is approximately 2% for k=2 and 4% for

Carles Badenes, Eduardo Bravo

The evolution of type Ia supernova binary system progenitors is highly uncertain. Several evolutionary models predict that the accretion of mass onto the white dwarf is accompanied by mass ejection from the binary in the form of a powerful wind, but very few observations have been made during the initial phase of formation of supernovae remnants, when the in

Miao Li

Based on a heuristic boost argument, we propose that the 4 dimensional de Sitter space can be described by a spherical Chern-Simons matrix model near the cosmological horizon, or models generalizing this simple choice. The dimension of the Hilbert space is naturally finite. We also make some comments on possible realization of holography in this approach, an

M. Calandra, O. Gunnarsson

We present a microscopic model for systems showing resistivity saturation. An essentially exact quantum Monte-Carlo calculation demonstrates that the model describes saturation. We give a simple explanation for saturation, using charge conservation and considering the limit where thermally excited phonons have destroyed the periodicity. Crucial model feature

A. Lucarelli, S. Lupi, P. Calvani, P. Maselli

La(8-x)Sr(x)Cu(8)O(20) is a non-superconducting cuprate, which exhibits a doubling of the elementary cell along the c axis. Its optical conductivity sigma (omega) has been first measured here, down to 20 K, in two single crystals with x = 1.56 and x = 2.24. Along c, sigma (omega) shows, in both samples, bands due to strongly bound charges, thus confirming th

M. Bertolini, V. L. Campos, G. Ferretti, P. Fré

We construct a new family of classical BPS solutions of type IIB supergravity describing 3-branes transverse to a 6-dimensional space with topology R^2*ALE. They are characterized by a non-trivial flux of the supergravity 2-forms through the homology 2-cycles of a generic smooth ALE manifold. Our solutions have two Killing spinors and thus preserve N=2 super

Marco Beijersbergen, Henk Hoekstra, Pieter G. van Dokkum, Thijs van der Hulst

We present a deep multi-colour CCD mosaic of the Coma cluster (Abell 1656), covering 5.2 deg^2 in the B and r bands, and 1.3 deg^2 in the U band. This large, homogeneous data set provides a valuable low redshift comparison sample for studies of galaxies in distant clusters. In this paper we present our survey, and study the dependence of the galaxy luminosit

A. N. Antonov, M. Gaidarov, M. V. Ivanov, D. N. Kadrev

The relativistic light-front dynamics (LFD) method has been shown to give a correct description of the most recent data for the deuteron monopole and quadrupole charge form factors obtained at the Jefferson Laboratory for elastic electron-deuteron scattering for six values of the squared momentum transfer between 0.66 and 1.7 (GeV/c)$^{2}$. The good agreemen

M. Yahiro, G. J. Mathews, K. Ichiki, T. Kajino

Recently, attempts have been made to understand the apparent near coincidence of the present dark energy and matter energy in terms of a dynamical attractor-like solution for the evolution of a scalar field. In these models the field couples with the dominant constituent and only acts like a cosmological constant after the onset of the matter-diminated epoch

Ko Furuta, Takeo Inami, Hiroaki Nakajima, Muneto Nitta

The field theory dual to the Freedman-Townsend model of a non-Abelian anti-symmetric tensor field is a nonlinear sigma model on the group manifold G. This can be extended to the duality between the Freedman-Townsend model coupled to Yang-Mills fields and a nonlinear sigma model on a coset space G/H. We present the supersymmetric extension of this duality, an

C. H. Otto Chui, Christian Mercat, Will Orrick, Paul A. Pearce

We construct integrable realizations of conformal twisted boundary conditions for ^sl(2) unitary minimal models on a torus. These conformal field theories are realized as the continuum scaling limit of critical A-D-E lattice models with positive spectral parameter. The integrable seam boundary conditions are labelled by (r,s,ζ) in (A_{g-2},A_{g-1},Γ) where Γ

H. -Q. Zhou, J. Links, R. H. McKenzie, M. D. Gould

Superconducting pairing of electrons in nanoscale metallic particles with discrete energy levels and a fixed number of electrons is described by the reduced BCS model Hamiltonian. We show that this model is integrable by the algebraic Bethe ansatz. The eigenstates, spectrum, conserved operators, integrals of motion, and norms of wave functions are obtained.

H. R. Christiansen, F. A. Schaposnik

We study the effect of noncommutativity of space on the physics of a quantum interferometer located in a rotating disk in a gauge field background. To this end, we develop a path-integral approach which allows defining an effective action from which relevant physical quantities can be computed as in the usual commutative case. For the specific case of a cons

Marcus Spradlin, Anastasia Volovich

We construct a new class of scalar noncommutative multi-solitons on an arbitrary Kahler manifold by using Berezin's geometric approach to quantization and its generalization to deformation quantization. We analyze the stability condition which arises from the leading 1/hbar correction to the soliton energy and for homogeneous Kahler manifolds obtain that

Caslav Brukner, Marek Zukowski, Anton Zeilinger

Entanglement, according to Erwin Schroedinger the essence of quantum mechanics, is at the heart of the Einstein-Podolsky-Rosen paradox and of the so called quantum-nonlocality - the fact that a local realistic explanation of quantum mechanics is not possible as quantitatively expressed by violation of Bell's inequalities. Even as entanglement gains incre

Renato M. Angelo, Kyoko Furuya, M. Carolina Nemes, Giancarlo Q. Pellegrino

The rise in linear entropy of a subsystem in the N-atom Jaynes-Cummings model is shown to be strongly influenced by the shape of the classical orbits of the underlying classical phase space: we find a one-to-one correspondence between maxima (minima) of the linear entropy and maxima (minima) of the expectation value of atomic excitation J_z. Since the expect

R. Paskauskas, L. You

We present the Schmidt decomposition for arbitrary wavefunctions of two indistinguishable bosons, extending the recent studies of entanglement or quantum correlations for two fermion systems [J. Schliemann et al., Phys. Rev. B {\bf 63}, 085311 (2001) and quant-ph/0012094]. We point out that the von Neumann entropy of the reduced single particle density matri

D. Salgado, J. L. Sanchez-Gomez

The stochastic methods in Hilbert space have been used both from a fundamental and a practical point of view. The result we report here concerns only the idea of applying these methods to model the evolution of quantum systems and does not enter into the question of their fundamental or practical status. It can be easily stated as follows: Once a quantum sto

Isabelle Bouchoule, Klaus Moelmer

We show that the interaction between Rydberg atomic states can provide continuous spin squeezing of atoms with two ground states. The interaction prevents the simultaneous excitation of more than a single atom in the sample to the Rydberg state, and we propose to utilize this blockade effect to realize an effective collective spin hamiltonian J_x^2-J_y^2. Wi

Partha Ghose, M. K. Samal

It is shown that both classical and quantum light can acquire a topological phase shift induced by classical gravity, and the latter is detectable in a laboratory-scale experiment.

Xijia Miao

The multiple-quantum operator algebra formalism has been exploited to construct generally an unsorted quantum search algorithm. The exponential propagator and its corresponding effective Hamiltonian are constructed explicitly that describe in quantum mechanics the time evolution of a multi- particle two-state quantum system from the initial state to the outp

Y. Nosochkov, Y. Cai, M. H. R. Donald, J. Irwin

The PEP-II interaction region is designed to accommodate asymmetric beam energies, head-on collisions, small bunch spacing and provide low beta* for high luminosity. Local correction schemes are implemented to compensate non-linear chromaticity from the IP doublets as well as coupling, orbit and focusing effects from the 6 Tm asymmetric detector solenoid. Th

Y. Nosochkov, J. Corbett

The Stanford Synchrotron Radiation Laboratory is investigating an accelerator upgrade project that would replace the present 130 nm rad FODO lattice with an 18 nm rad double bend achromat (DBA) lattice: SPEAR 3. The low emittance design yields a high brightness beam, but the stronger focusing in the DBA lattice increases chromaticity and beam sensitivity to

Y. M. Nosochkov, T. O. Raubenheimer

In this note, we briefly review the current lattice of the NLC extraction line which was designed for the nominal NLC beam parameters. Then we describe the beam parameters for the high luminosity option with larger beam disruption parameter and discuss its effect on beam loss in the extraction line. Finally, we present a summary of the optics study aimed at

J. Corbett, Y. Nosochkov

The SPEAR 3 upgrade lattice will provide much reduced beam emittance to increase the brightness of synchrotron radiation beams from wigglers and undulators. Seven existing insertion devices will be used in the lattice. In this paper we review the wiggler parameters, outline the wiggler compensation scheme, and evaluate wiggler effect on the optics and dynami

J. Corbett, Y. Nosochkov, J. Safranek, A. Garren

The SSRL is investigating an accelerator upgrade project to replace the present 130 nm rad FODO lattice with an 18 nm rad double bend achromat lattice: SPEAR 3. In this paper, we review the methods used to maximize the SPEAR 3 dynamic aperture including optimization of linear optics, betatron tune, chromaticity and coupling correction, and effects of machine

Y. Nosochkov, T. O. Raubenheimer, K. Thompson, M. Woods

The two main functions of the NLC extraction line include: 1) transmission of the outgoing disrupted beam and secondary particles to the dump with minimal losses; and 2) beam diagnostics and control. In this report, we describe the extraction line optics, present the results of tracking studies, and discuss the extraction line instrumentation.

Y. Nosochkov, T. O. Raubenheimer, K. A. Thompson

Properties of the disrupted NLC beam at the Interaction Point (IP) and particle loss in the extraction line are analyzed as a function of beam-to-beam position and angular offset at IP. The simulations show that disruption and beam loss maximize when the vertical beam separation at IP is about 20 times the rms vertical beam size. The horizontal offset does n

Y. Nosochkov, T. O. Raubenheimer

The NLC extraction line provides a secondary focal point with a low beta function and 2 cm dispersion which can be used for measurement of the beam energy spectrum. In this study, tracking simulations were performed to transport the 0.5 TeV electron beam from the Interaction Point (IP) to the secondary focus (SF), ``measure'' the resultant transverse

C. L. Herzenberg

Interactions with ordinary matter of a flux of high-speed uncharged dark matter particles pervasively present in space are examined. In this model, we find that the property of matter that we designate as mass becomes a measure of the interaction cross section of ordinary matter with the flux of dark matter. From this model emerge both a flux-mediated attrac

Y. Nosochkov, J. Corbett, T. Rabedeau

The SPEAR 3 light source has two 7.6 m straight sections one of which is available for new insertion devices (ID). By reducing the vertical beta function at the center of the straight from 9.8 m to 1.5 m, the beam size can be decreased from 44 to 17 microns to reduce the ID gap, but the ID length may be limited by the increased beta-y variation in the ID. Al

Martina Hentschel, Matthias Vojta

Motivated by the recent observation of periodic filter characteristics of an oval-shaped micro-cavity, we study the possible interference of multiple beams in the far field of a laser-illuminated quadrupolar glass fiber. From numerical ray-tracing simulations of the experimental situation we obtain the interference-relevant length-difference spectrum and com

H. Hickman

Reversing the flow of time between Casimir plates raises the question of whether or not a recently deceased, intact organism could be brought back to life. The odds are not good.

V. R. Manfredi, L. Salasnich

We investigate the spectral statistics of the asymmetric rotor model (triaxial rigid rotator). The asymmetric top is classically integrable and, according to the Berry-Tabor theory, its spectral statistics should be Poissonian. Surprisingly, our numerical results show that the nearest neighbor spacing distribution $P(s)$ and the spectral rigidity $Δ_3(L)$ do

J. Carlson, J. Jourdan, R. Schiavilla, I. Sick

The $^3$He and $^4$He longitudinal and transverse response functions are determined from an analysis of the world data on quasi-elastic inclusive electron scattering. The corresponding Euclidean response functions are derived and compared to those calculated with Green's function Monte Carlo methods, using realistic interactions and currents. Large contr

M. Asakawa, U. Heinz, B. Muller

The magnitude of the local fluctuations of the net baryon number and electric charge differs widely between the confined and deconfined phases, and the difference is partially frozen at an early stage in relativistic heavy ion collisions. These fluctuations may thus be useful probes of the temporary formation of a deconfined state in such collisions.

S. S. Kamalov, D. Drechsel, L. Tiator, S. N. Yang

Results of new analysis of pion photoproduction data obtained with Dynamical and MAID models are presented

Sergey Y. Panitkin

We give an overview of the latest results of HBT and fluctuations studies in heavy ion collisions presented during the Quark Matter 2001 Conference.

F. Videbaek

The status of stopping in heavy ion reactions is reviewed by comparing available data in pp, pA and AA systems over the energy regime sqrt(s_NN) ~ 2.5 - 130 GeV/c. The data consist of average rapidity losses, anti-proton over proton ratios, and net-baryon values at mid-rapidity. The overall features of nuclear stopping are reasonbly well described by simple

Yu. V. Brezhnev

New exact solvable elliptic potentials with free constants for the spectral problems of the third order are found. A time dependence of such potentials gives their isospectral deformations and solutions of nonlinear integrable equations.

M. Boiti, F. Pempinelli, A. K. Pogrebkov, B. Prinari

Inverse scattering transform method of the heat equation is developed for a special subclass of potentials nondecaying at space infinity---perturbations of the one-soliton potential by means of decaying two-dimensional functions. Extended resolvent, Green's functions, and Jost solutions are introduced and their properties are investigated in detail. The

Michael Blank

To study the convergence to equilibrium in random maps we developed the spectral theory of the corresponding transfer (Perron-Frobenius) operators acting in a certain Banach space of generalized functions. The random maps under study in a sense fill the gap between expanding and hyperbolic systems since among their (deterministic) components there are both e

Wang Shikun, Wu Ke, Wu Xiaoning, Yu Delong

In this paper, we considered the q-deformation of AKNS-D hierarchy, proved the bilinear identity and give out the $τ$-function of the q-deformed AKNS-D hierarchy.

George Chavchanidze, Levan Tskipuri

In the present paper detailed coordinate free description of the classical and quantum dynamics of free particle on SU(2) group manifold is carried out.

George Chavchanidze

In the past few years both non-Noether symmetries and bidifferential calculi has been successfully used in generating conservation laws and both lead to the similar families of conserved quantities.Here relationship between Lutzky's integrals of motion [3-4] and bidifferential calculi is briefly disscussed.

Andrew Granville, Kannan Soundararajan

Given a non-principal Dirichlet character chi mod q, an important problem in number theory is to obtain good estimates for the size of L(1,chi). In this paper we focus on sharpening the upper bounds known for |L(1,chi)|; in particular, we wish to determine constants c (as small as possible) for which the bound |L(1,chi)| <= (c+o(1)) log q holds.

Pavel Etingof, Victor Ginzburg

Let W be a finite Coxeter group in a Euclidean vector space V, and m a W-invariant Z_+-valued function on the set of reflections in W. Chalyh and Veselov introduced in an interesting algebra Q_m, called the algebra of m-quasiinvariants for W. This is the algebra of quantum integrals of the rational Calogero-Moser system with coupling constants m. In a recent

Kouki Taniyama, Akira Yasuhara

We define $A_k$-moves for embeddings of a finite graph into the 3-sphere for each natural number $k$. Let $A_k$-equivalence denote an equivalence relation generated by $A_k$-moves and ambient isotopy. $A_k$-equivalence implies $A_{k-1}$-equivalence. Let ${\cal F}$ be an $A_{k-1}$-equivalence class of the embeddings of a finite graph into the 3-sphere. Let ${

Bertram Kostant

A Lie superalgebrea of Riemannian type leads to a representation of a quadratic Lie algebra into a Weyl algebra. A necessary and sufficient condition that such a representation leads to a Lie superalgebra of Riemannian type is that the Casimir maps to a constant.

Sergey V. Ludkovsky

Quasi-invariant and pseudo-differentiable measures on a Banach space $X$ over a non-Archimedean locally compact infinite field with a non-trivial valuation are defined and constructed. Measures are considered with values in non-Archimedean fields, for example, the field $\bf Q_p$ of $p$- adic numbers. Theorems and criteria are formulated and proved about qua

Sergey V. Ludkovsky

Quasi-invariant and pseudo-differentiable measures on a Banach space $X$ over a non-Archimedean locally compact infinite field with a non-trivial valuation are defined and constructed. Measures are considered with values in $\bf R$. Theorems and criteria are formulated and proved about quasi-invariance and pseudo-differentiability of measures relative to lin

J. B. Lasserre, E. S. Zeron

We provide two algorithms for computing the volume of a convex polytope with half-space representation {x>=0; Ax <=b} for some (m,n) matrix A and some m-vector b. Both algorithms have a O(n^m) computational complexity which makes them especially attractive for large n and relatively small m when the other methods with O(m^n) complexity fail. The methodology

N. Brodsky, A. Chigogidze, A. Karasev

We prove extension-dimensional versions of finite dimensional selection and approximation theorems. As applications, we obtain several results on extension dimension.

A. Tsemo

In this paper we study n-composition series of affine manifolds. One composition series are classified using gerbe theory. It is natural to think that n-composition series must be classified using n-gerbe theory. In the last section of this, we propose a notion of abelian n-gerbe theory

Samuel Grushevsky

An explicit upper bound for the Weil-Petersson volumes of the moduli spaces of punctured Riemann surfaces is obtained, using Penner&#39;s combinatorial integration scheme with embedded trivalent graphs. It is shown that for a fixed number of punctures n and for genus g going to infinity, the Weil-Petersson volume of M_{g,n} has an upper bound c^g g^{2g}. Her

J. R. Hiller, S. Pinsky, U. Trittmann

We apply supersymmetric discrete light-cone quantization (SDLCQ) to the study of supersymmetric Yang-Mills theory on R x S^1 x S^1. One of the compact directions is chosen to be light-like and the other to be space-like. Since the SDLCQ regularization explicitly preserves supersymmetry, this theory is totally finite, and thus we can solve for bound-state wav

Frank Ferrari

We investigate the large Nc limit of pure N=2 supersymmetric gauge theory with gauge group SU(Nc) by using the exact low energy effective action. Typical one-complex dimensional sections of the moduli space parametrized by a global complex mass scale v display three qualitatively different regions depending on the ratio between |v| and the dynamically genera

G. P. Vacca

A review on how the Odderon idea does appear in QCD is given. In the last years it has been developed a non-perturbative QCD approach based on the stochastic vacuum model and a perturbative one based on resummation techniques in the small x QCD region. Last developments on the perturbative analysis are shown in some details, in particular in application to d

A. K. Ciftci, R. Ciftci, S. Sultansoy

The potential of $μ^{+}μ^{-}$ colliders to investigate the fourth SM family fermions predicted by flavour democracy has been analyzed. It is shown that muon colliders are advantageous for both pair production of fourth family fermions and resonance production of fourth family quarkonia. Also isosinglet quarks production at $μ^{+}μ^{-}$ colliders has been inv

M. Besancon

A short review of phenomenological and experimental aspects of extra spatial dimensions at colliders is presented.

Gulsheen Ahuja, Monika Randhawa, Manmohan Gupta

The recently reanalysed LSND data is investigated in the context of three flavor oscillations, with an emphasis on mass hierarchies and $s_{13}$. The resultant mass hierarchies and oscillation angles are tested with regard to &#34;key&#34; features of solar neutrinos and atmospheric neutrinos, e.g., &#34;average&#34; survival probability in the case of solar

Anna Hasenfratz, Francesco Knechtli

Staggered fermions with smeared links can have greatly improved chiral properties. In a recent paper we introduced a simple and effective method to simulate four flavors of staggered smeared link fermions. In this work we extend the four flavor method to two flavors. We define the two flavor action by the square root of the four flavor fermionic determinant

Sergio Caracciolo, Andrea Pelissetto, Antonio Rago

We have redone a recent two-loop computation of the critical mass for Wilson fermions in lattice QCD by evaluating Feynman integrals with the coordinate-space method. We present the results for different types of infrared regularization. We confirm both the previous numerical estimates and the power of the coordinate-space method whenever high accuracy is ne

A. Hasenfratz, F. Knechtli

We study the finite temperature phase transition of four flavor staggered fermions with hypercubic fat link actions on N_t=4 and N_t=6 temporal lattices. Our fat links are constructed with hypercubic blocking (HYP) and therefore are very compact. We present a new algorithm for simulating fermions coupled to HYP fat links. The algorithm has a simple form base

Roberta Arnaldi

The J/psi suppression observed by the NA50 experiment is one of the most striking signatures for quark gluon plasma formation in Pb-Pb collisions at 158 AGeV. The J/psi production has been studied as a function of the centrality of the collision estimated via the forward energy EZDC released in a zero degree calorimeter (ZDC). The study of the correlation be

H1 Collaboration, C. Adloff

Three-jet production is studied for the first time in deep-inelastic positron-proton scattering. The measurement carried out with the H1 detector at HERA covers a large range of four-momentum transfer squared 5 < Q^2 < 5000 GeV^2 and invariant three-jet masses 25 < M_(3jet) < 140 GeV. Jets are defined by the inclusive k_T algorithm in the Breit frame. The si

NA48 Collaboration

A value of (-6.1 +- 0.9_{stat} +- 0.5_{syst})*10^{-3} is obtained for the quadratic slope parameter h in the K_L -> 3π^0 decay Dalitz plot at the NA48 experiment at the CERN SPS. The result is based on 14.7*10^6 fully reconstructed K_L -> 3π^0 -> 6γdecays. This is the most precise measurement of any of the Dalitz plot slope parameters in the charged and neut

Giorgio Chiarelli

The proposed Run IIb of the Tevatron Collider will provide 15 fb-1 worth of ppbar data at c.o.m energy of 2 TeV per experiment by year 2007. We review the plans of the Tevatron accelerator complex upgrade and the plans for the upgrades of the experiments to match this challenge. Perspectives for the discovery of an Higgs particle are reviewed and the concret

A. Valassi

In the energy region of LEP2 and above, four fermion final states in e+e- collisions can be produced by Feynman diagrams involving two, one or zero resonant bosons...

Neil J. Cornish

The gravitational waveforms of a chaotic system will exhibit sensitive dependence on initial conditions. The waveforms of nearby orbits decohere on a timescale fixed by the largest Lyapunov exponent of the orbit. The loss of coherence has important observational consequences for systems where the Lyapunov timescale is short compared to the chirp timescale. D

S. G. Ghosh

We investigate the occurrence of naked singularities in the spherically symmetric, plane symmetric and cylindrically symmetric collapse of charged null fluid in an anti-de Sitter background. The naked singularities are found to be strong in Tipler&#39;s sense and thus violate the cosmic censorship conjecture, but not hoop conjecture.

Yair Even-Zohar, Dan Roth

Many classification problems require decisions among a large number of competing classes. These tasks, however, are not handled well by general purpose learning methods and are usually addressed in an ad-hoc fashion. We suggest a general approach -- a sequential learning model that utilizes classifiers to sequentially restrict the number of competing classes

Yuval Krymolowski

Statistical NLP systems are frequently evaluated and compared on the basis of their performances on a single split of training and test data. Results obtained using a single split are, however, subject to sampling noise. In this paper we argue in favour of reporting a distribution of performance figures, obtained by resampling the training data, rather than

T. Papenbrock, A. N. Salgueiro, H. A. Weidenmueller

We derive two different sets of rate equations for sympathetic cooling of harmonically trapped Bosons or Fermions. The rate equations are obtained from a master equation derived earlier by Lewenstein et al. [Phys. Rev. A 51 (1995) 4617] by means of decoherence and ergodicity arguments. We show analytically that the thermal equilibrium state is a stationary s

Baowen Li, Hong Zhao, Bambi Hu

In his comment, Dhar (cond-mat/0106349) claims that the existence and uniqueness of a nonequilibrium stationary state has been proved by Lebowitz et al. We should point out that our observation does not contradict the proof. They have only proved that when a (mass) disordered harmonic chain is placed in contact with stochastic reservoirs of the Langevin type

X. Vinas, R. Roth, P. Schuck, J. Wambach

The quantum-kinetic energy of a finite number of trapped fermionic atoms provides a restoring force for shear motion due to a distortion of the momentum distribution. In analogy to the twist mode of nuclear physics it is proposed that counter-rotating the upper and lower hemisphere of a spherical atomic cloud yields a finite-frequency mode closely related to

Mark I. Shliomis

A new magnetization equation recently derived from irreversible thermodynamics is employed to the calculation of an increase of ferrofluid viscosity in a magnetic field. Results of the calculations are compared with those obtained on the basis of two well-known magnetization equations. One of the two was obtained phenomenologically, another one was derived m

Mark I. Shliomis

It is shown and discussed how the conventional system of hydrodynamic equations for ferrofluids was derived. The set consists of the equation of fluid motion, the Maxwell equations, and the magnetization equation. The latter was recently revised by Felderhof [Phys. Rev. E, v.62, p.3848 (2000)]. His phenomenological magnetization equation looks rather like co

Mark I. Shliomis

Convective instability in a ferrofluid layer heated from below or from above in the presence of a uniform vertical magnetic field is investigated theoretically. Convection is caused by a magnetic mechanism based on the temperature and concentration dependence of magnetization. An imposed temperature gradient establishes (by the Soret effect) a concentration

S. Denev, D. W. Snoke

A comprehensive study of the exciton relaxation processes in Cu2O has led to some surprises. We find that the ortho-para conversion rate becomes slower at high stress, and that the Auger nonradiative recombination rate increases with stress, with apparently no Auger recombination at zero stress. These results have important consequences for the pursuit of Bo

Brian B. Laird

Largely due to its role in nucleation and crystal-growth, the free energy of the crystal-melt interfacial free energy is an object of considerable interest across a number of scientific disciplines, especially in the materials-, colloid- and atmospheric sciences. Over fifty years ago, Turnbull observed that the interfacial free energies (scaled by the mean i

Hong Qian

In recent single-particle tracking (SPT) measurements on {\it Listeria monocytogenes} motility {\em in vitro}, the actin-based stochastic dynamics of the bacterium movement is analyzed statistically (Kuo and McGrath, 2000). The mean-square displacement (MSD) of the detrended trajectory exhibit a linear behavior; it has been suggested that a corresponding ana

D. A. Papaconstantopoulos, M. J. Meh

We present a careful recasting of first-principles band structure calculations for MgB2 in a non-orthogonal sp-tight-binding (TB) basis. Our TB results almost exactly reproduce our full potential linearized augmented plane wave results for the energy bands, the densities of states and the total energies. Our procedure generates transferable Slater-Koster par

F. Laube, G. Goll, J. Hagel, H. v. Löhneysen

We performed point-contact spectroscopy on the binary superconductor MgB$_2$. The differential conductance shows gap-related structures which vary in width and position from contact to contact. The distribution of energy gaps shows a distinct accumulation around 1.7 and 7 meV which is associated with the occurrence of a small and a large energy gap in MgB$_2

Yu. G. Semenov, V. A. Stephanovich

We suggest an approach to account for spatial (composition) and thermal fluctuations in &#34;disordered&#34; magnetic models (e.g. Heisenberg, Ising) with given spatial dependence of magnetic spin-spin interaction. Our approach is based on introduction of fluctuating molecular field (rather than mean field) acting between the spins. The distribution function

Jan von Delft, R. Poghossian

We show in detail how Richardson&#39;s exact solution of a discrete-state BCS (DBCS) model can be recovered as a special case of an algebraic Bethe Ansatz solution of the inhomogeneous XXX vertex model with twisted boundary conditions: by implementing the twist using Sklyanin&#39;s K-matrix construction and taking the quasiclassical limit, one obtains a comp

A. Mourachkine

Tunneling measurements have been carried out on heavily underdoped, slightly overdoped and partially Ni-substituted Bi2212 single crystals by using a break-junction technique. We find that in-plane tunneling spectra below Tc are the combination of incoherent part from the pseudogap and coherent quasiparticle peaks. There is a clear correlation between the ma

B. J. Baelus, S. V. Yampolskii, F. M. Peeters, E. Montevecchi

The superconducting state of an infinitely long superconducting cylinder surrounded by a medium which enhances its superconductivity near the boundary is studied within the nonlinear Ginzburg-Landau theory. This enhancement can be due to the proximity of another superconductor or due to surface treatment. Quantities like the free energy, the magnetization an

Ari Belenkiy

Each market has its singular characteristic. Its inner structure is directly responsible for the observed distributions of returns though this fact is widely overlooked. Big orders lead to doubling the tails. The behavior of a market maker with many or few ``friends&#39;&#39; who can reliably loan money or stock to him is quite different from the one without