December 2000 arXiv papers — page 10

W. F. Chen, G. Leibbrandt

Vector supersymmetry is shown to exist also in light-cone gauge Chern-Simons theory. Using a gauge invariant regularization scheme, we demonstrate explicitly that the finite quantum correction to the coupling constant of Chern-Simons theory is intimately associated with the breaking of vector supersymmetry at the regularization level. The advantage of invest

M. Bertolini, A. Lerda

We review how to describe the stable non-BPS D-branes of type II string theory from a classical perspective, and discuss the properties of the space-time geometry associated to these configurations. This is relevant in order to see whether and how the gauge/gravity correspondence can be formulated in non-conformal and non-supersymmetric settings.

Fred Browning, Darwin Chang, Wai-Yee Keung

We investigate a potentially large CP violating asymmetry in the decay of a neutral scalar or pseudoscalar Higgs boson into the top-anti-top pair. The source of the CP nonconservation is the complex mixing in the (left-right) stop sector. One of the interesting consequence is the different rates of the Higgs boson decays into CP conjugate polarized states.

Ali Abbasabadi, Alberto Devoto, Wayne W. Repko

The one-loop helicity amplitudes for the elastic scattering process $\gamma\nu\to\gamma\nu$ in the Standard Model are computed at high center of mass energies. A general decomposition of the amplitudes is utilized to investigate the validity of some of the key features of our results. In the center of mass, where $\sqrt{s} = 2\omega$, the cross section grows

F. A. Chishtie, V. Elias

Known perturbative expressions for the decay rates of 115 GeV Higgs particle into either two gluons or a $b\bar{b}$ pair are shown to exhibit renormalization-scale-($μ$)-dependence that is largely removed via renormalization-group/Pade-approximant estimates of these rates' next order contributions. The extrema in $μ$ characterizing both rates, as determi

Stefan Roesler, Ralph Engel, Johannes Ranft

A new version of the Monte Carlo event generator DPMJET is presented. It is a code system based on the Dual Parton Model and unifies all features of the DTUNUC-2, DPMJET-II and PHOJET 1.12 event generators. DPMJET-III allows the simulation of hadron-hadron, hadron-nucleus, nucleus-nucleus, photon-hadron, photon-photon and photon-nucleus interactions from a f

Richard Hawkings, Stephane Willocq

B physics results from e+ e- annihilation at the Z0 resonance are reviewed. A vast program is summarised, including the study of B+, B0d, B0s and b baryon lifetimes, the time dependence of B0d and B0s oscillations, the width difference in the B0s system, and the measurements of the magnitudes of the CKM matrix elements Vcb and Vub.

F. Jegerlehner, K. Kolodziej

The fermion mass effects in e+ e- --> 4f and in the corresponding bremsstrahlung reactions in the presence of realistic cuts are studied. It is shown that, for some four--fermion final states, the mass effects become sizeable to the extent that they may affect the accuracy of theoretical predictions which is required to be better than 1%.

Zhiqing Zhang

Since its commissioning in 1991, the ep collider HERA has been running successfully for almost a decade without stopping improving its performance. In this report, the inclusive cross section and structure function measurements for the deep inelastic scattering of neutral and charged current processes in the full HERA kinematic domain are reviewed. The resul

A. E. Inopin

We have reconstructed Regge trajectories (RT), using all existing data on masses and spin-parities of all currently known hadrons. In this resonance energy region meson and baryon RT are grossly nonlinear, and only 12% of all RT could be classified as a linear, with $σ=0$, $α'\simeq 0.9$ GeV${}^{-2}$.

M. V. Garzelli, C. Giunti

We calculate with Monte Carlo the goodness of fit and the confidence level of the standard allowed regions for the neutrino oscillation parameters obtained from the fit of the total rates measured in solar neutrino experiments. We show that they are significantly overestimated in the standard method. We also calculate exact allowed regions with correct frequ

U. Guenther, A. Kuklov, A. Zhuk

We discuss the stability of atoms and nucleons in the presence of multidimensional gravity characterized by the unified energy scale 1TeV. We point out that the multidimensional gravitational attraction can create additional bound states deep inside of atomic and nucleon constituents. These states would be characterized by sizes comparable to the TeV scale d

Laura Covi

We review the connection between inflationary models and observations and concentrate to describe models based on softly broken supersymmetry, in particular running mass models, and their predictions. We then present a fit of the spectral index of the curvature perturbation, assuming a flat $Λ$CDM cosmology.

Eric Braaten, Jungil Lee

The polarization of inclusive Upsilon(nS) at the Fermilab Tevatron is calculated within the nonrelativistic QCD factorization framework. We use a recent determination of the NRQCD matrix elements from fitting the CDF data on bottomonium production from Run IB of the Tevatron. The result for the polarization of Upsilon(1S) integrated over the transverse momen

W. Kilian

The session on precision studies of electroweak interactions is summarized. The contributions address the bilinear, trilinear, quartic as well as heavy-quark interactions of the electroweak gauge bosons. This makes up a picture of the physics of electroweak symmetry and symmetry breaking which can be investigated with the proposed design of e+e- Linear Colli

A. Ringwald, F. Schrempp

In view of the intriguing, preliminary search results for instanton-induced events at HERA from the H1 collaboration, some important remaining theoretical issues are discussed. Notably, the question is addressed, to which extent the H1 analysis may be directly compared to our original predictions from instanton-perturbation theory, since certain fiducial cut

W. Y. Wang, Y. L. Wu

Exclusive semileptonic B decays into excited charmed mesons ($D_1$, $D^*_2$) are studied up to the order of $1/m_Q$ in the framework of the heavy quark effective field theory (HQEFT), which contains the contributions of both particles and antiparticles. Two wave functions $η^b_0$ and $η^c_0$, which characterize the contributions from the kinematic operator a

Jiao Lin Xu

From the quark confinement idea, we conjecture that the quarks compose colorless particles (uud and udd - the Lee Particles) and then the Lee Particles construct a body center cubic lattice in the vacuum. In terms of the energy band theory, from the symmetries of the body center cubic periodic field, we deduce the baryon spectrum (with a united mass formula)

Thomas DeGrand, Anna Hasenfratz

We explore the properties of low lying eigenmodes of fermions in the quenched approximation of lattice QCD. The fermion action is a recently proposed overlap action and has exact chiral symmetry. We find that chiral zero-eigenvalue modes are localized in space and their positions correlate strongly with the locations (as defined through the density of pure g

K. Abe

We set a preliminary 95% C.L. exclusion on the oscillation frequency of B0s - B0s-bar mixing using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment at the SLC between 1996 and 1998. The analyses determine the b-hadron flavor at production by exploiting the large forward-backward asymmetry of polarized Z0 -> b b-bar decays as well as inf

Francesc Fayos, Carlos F. Sopuerta

In vacuum space-times the exterior derivative of a Killing vector field is a 2-form (named here as the Papapetrou field) that satisfies Maxwell's equations without electromagnetic sources. In this paper, using the algebraic structure of the Papapetrou field, we will set up a new formalism for the study of vacuum space-times with an isometry, which is sui

A. B. Batista, J. C. Fabris, S. V. B. Goncalves, J. Tossa

A qualitative analysis of a scalar-tensor cosmological model, with an exponential potential for the scalar field, is performed. The phase diagram for the flat case is constructed. It is shown that solutions with an initial and final inflationary behaviour appear. The conditions for which the scenario favored by supernova type Ia observations becomes an attra

J. Spinelly, V. B. Bezerra

We calculate the electrostatic potential generated by a point charge in the space-time of Reissner-Nordstrom with a conical defect. An expression for the self-energy is also presented.

T. Damour, B. R. Iyer, B. S. Sathyaprakash

Detecting binary black holes in interferometer data requires an accurate knowledge of the orbital phase evolution of the system. From the point of view of data analysis one also needs fast algorithms to compute the templates that will employed in searching for black hole binaries. Recently, there has been progress on both these fronts: On the one hand, re-su

D. Bini, C. Germani, R. T. Jantzen

The integral formulation of Maxwell's equations expressed in terms of an arbitrary observer family in a curved spacetime is developed and used to clarify the meaning of the lines of force associated with observer-dependent electric and magnetic fields.

Nobuyuki Sakai, John D. Barrow

We consider a modified ``Swiss cheese'' model in the Brans-Dicke theory, and discuss the evolution of black holes in the expanding universe. We define the black hole radius by the Misner-Sharp mass and find the time evolution for dust and vacuum universes.

Constantino Tsallis

All presently available results lead to the conclusion that nonextensivity, in the sense of nonextensive statistical mechanics (i.e., $q \ne 1$), does {\it not} modify anything to the second principle of thermodynamics, which therefore holds in the usual way. Moreover, some claims in the literature that this principle can be violated for specific anomalous s

R. Jackiw, C. Rebbi, J. R. Schrieffer

We argue that electrons in liquid helium bubbles are not fractional, they are entangled.

Alejandro B. Kolton, Daniel Dominguez, Niels Gronbech-Jensen

We find mode-locking steps in simulated current-voltage characteristics of ac-driven vortex lattices with {\it random} pinning. For low frequencies there is mode-locking above a finite ac force amplitude, while for large frequencies there is mode-locking for any small ac force. This is correlated with the nature of temporal order in the different regimes in

E. P. De Poortere, E. Tutuc, S. J. Papadakis, M. Shayegan

We report a new manifestation of first-order magnetic transitions in two-dimensional electron systems. This phenomenon occurs in aluminum arsenide quantum wells with sufficiently low carrier densities and appears as a set of hysteretic spikes in the resistance of a sample placed in crossed parallel and perpendicular magnetic fields, each spike occurring at t

A. F. Rozenfeld, C. J. Tessone, E. Albano, H. S. Wio

Noise induced changes in the critical and oscillatory behavior of a Prey-Predator system are studied using power spectrum density and Spectral Amplification Factor (SAF) analysis. In the absence of external noise, the population densities exhibit three kinds of asymptotic behavior, namely: Absorbing State, Fixed Point (FP) and an Oscillatory Regime (OR) with

M. D. Girardeau, E. M. Wright

van Hove's theory of scattering of probe particles by a macroscopic target is generalized so as to relate the differential cross section for atomic ejection via stimulated Raman transitions to one-particle momentum-time correlations and momentum distributions of 1D trapped gases. This method is well suited to probing the longitudinal momentum distributio

G. M. Bruun

We consider the collective mode spectrum of a normal Fermi gas in a spherical harmonic trap. Using a self-consistent random-phase-approximation, we systematically examine the effects of the two-body interactions on the modes of various symmetries. For weak coupling where the spectrum is shifted very little away from the ideal gas case, a sum-rule approach is

E. Almaas, D. Stroud

We describe a simple dynamical model for an underdamped Josephson junction array coupled to a resonant cavity. From numerical solutions of the model in one dimension, we find that (i) current-voltage characteristics of the array have self-induced resonant steps (SIRS), (ii) at fixed disorder and coupling strength, the array locks into a coherent, periodic st

Richard P. Sear

Colloidal suspensions with free polymer coils which are larger than the colloidal particles are considered. The polymer-colloid interaction is modeled by an extension of the Asakura-Oosawa model. Phase separation occurs into dilute and dense fluid phases of colloidal particles when polymer is added. The critical density of this transition tends to zero as th

Mats-Erik Pistol

We have found the equations that determine the self-adjoint extensions, and thus the boundary conditions, of the differential operator used in the multi-band k.p-theory, when the coefficients in the Kane-matrix are piecewise constant. Both the one-dimensional and the three-dimensional case have been investigated. A numerical calculation shows that the choice

F. Chandelier, Y. Georgelin, T. Masson, J. -C. Wallet

We consider a general class of non-local MCS models whose usual minimal coupling to a conserved current is supplemented with a (non-minimal) magnetic Pauli-type coupling. We find that the considered models exhibit a self-duality whenever the magnetic coupling constant reaches a special value: the partition function is invariant under a set of transformations

Juan J. Alonso, Miguel A. Munoz

We present a study of the influence of different types of disorder on systems in the Ising universality class by employing both a dynamical field theory approach and extensive Monte Carlo simulations. We reproduce some well known results for the case of quenched disorder (random temperature and random field), and analyze the effect of four different types of

S. Cilla, F . Falo, L. M. Floria

We analyze here the minimal conditions for directional motion (net flow in phase space) of a molecular motor placed on a mirror-symmetric environment and driven by a center-symmetric and time-periodic force field. The complete characterization of the deterministic limit of the dissipative dynamics of several realizations of this minimal model, reveals a comp

D. S. Dean, I. T. Drummond, R. R. Horgan

The advection of a passive scalar by a quenched (frozen) incompressible velocity field is studied by extensive high precision numerical simulation and various approximation schemes. We show that second order self consistent perturbation theory, in the absence of helicity, perfectly predicts the effective diffusivity of a tracer particle in such a field. In t

L. Bocquet, W. Losert, D. Schalk, T. C. Lubensky

We analyze the main features of granular shear flow through experimental measurements in a Couette geometry and a comparison to a locally Newtonian, continuum model of granular flow. The model is based on earlier hydrodynamic models, adjusted to take into account the experimentally observed coupling between fluctuations in particle motion and mean-flow prope

Th. Busch, J. R. Anglin

We investigate dark-bright vector solitary wave solutions to the coupled non-linear Schrödinger equations which describe an inhomogeneous two-species Bose-Einstein condensate. While these structures are well known in non-linear fiber optics, we show that spatial inhomogeneity strongly affects their motion, stability, and interaction, and that current technol

H. Kondo, S. Ishihara, S. Maekawa

We present a theory of the resonant inelastic x-ray scattering (RIXS) to study electronic excitations in orbital ordered manganites. The charge and orbital excitations of the Mn 3d electron are caused by the Coulomb interactions in the intermediate scattering state. The scattering cross section is formulated by the Liouville operator method where the local a

F. Taddei, S. Sanvito, C. J. Lambert

We study spin-dependent electronic transport across ferromagnet/superconductor ballistic junctions modeled using tight-binding Hamiltonians with s, p and d orbitals and material-specific parameters. We show that by accurately modeling the band structure of the bulk materials, one can reproduce the measured differential conductance of Cu/Pb nanocontacts. In c

Joakim Bergli, Yuri Galperin

Absorption of surface acoustic waves by a two-dimensional electron gas in a perpendicular magnetic field is considered. The structure of such system at the filling factor $ν$ close to 1/2 can be understood as a gas of {\em composite fermions}. It is shown that the absorption at $ν=1/2 $ can be strongly nonlinear, while small deviation form 1/2 will restore t

G. E. Volovik, V. B. Eltsov, M. Krusius

In He-3 superfluids quantized vorticity can take many different forms: It can appear as distributed periodic textures, as sheets, or as lines. In the anisotropic He-3A phase in most cases the amplitude of the order parameter remains constant throughout the vortex structure and only its orientation changes in space. In the quasi-isotropic He-3B phase vortex l

Kirill N. Alekseev, Feodor V. Kusmartsev

We discuss an effect of dc current and dc voltage (stopping bias) generation in a semiconductor superlattice subjected by an ac electric field and its phase-shifted n-th harmonic. In the low field limit, we find a simple dependence of dc voltage on a strength, frequency, and relative phase of mixing harmonics for an arbitrary even value of n. We show that th

R. Kofman, P. Cheyssac, F. Celestini

Comment on the paper of T.Bachels, H. J. Güntherodt and R.Schäfer : "Melting of Isolated Tin Nanoparticles".

W. Prellier, B. Raveau

In a recent paper (2000 \QTR{it}{J. Phys.: Condens. Matter} \QTR{bf}{12} L133) Lee \QTR{it}{et al.} have studied the transport properties of Pr$_{0.65}$Ca$_{0.35}$MnO$_{3}$ thin films. They claimed that they are able to controlled the charge-ordered (CO) state by the lattice strains. We propose herein another alternative since another indexation of the orien

Bjorn Skjetne, Torbjorn Helle, Alex Hansen

The roughness of crack interfaces is reported in quasistatic fracture, using an elastic network of beams with random breaking thresholds. For strong disorders we obtain 0.86(3) for the roughness exponent, a result which is very different from the minimum energy surface exponent, i.e., the value 2/3. A cross-over to lower values is observed as the disorder is

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

Critical scattering analyses for dilute antiferromagnets are made difficult by the lack of predicted theoretical line shapes beyond mean-field models. Nevertheless, with the use of some general scaling assumptions we have developed a procedure by which we can analyze the equilibrium critical scattering in these systems for H=0, the random-exchange Ising mode

Shoji Yamamoto

In response to recent nuclear-magnetic-resonance measurements on a ferrimagnetic chain compound NiCu(C_7H_6N_2O_6)(H_2O)_3 2H_2O [Solid State Commun. {\bf 113} (2000) 433], we calculate the nuclear spin-lattice relaxation rate 1/T_1 in terms of a modified spin-wave theory. Emphasizing that the dominant relaxation mechanism arises from the direct (single-magn

Hal Tasaki

We treat a quantum mechanical system with certain general properties which are expected to be common in macroscopic quantum systems. Starting from a PURE initial state (which may not describe an equilibrium) in which energy is mildly concentrated at a single value, we consider a time evolution determined by a time-dependent Hamiltonian as a model of an adiab

S. Fratini F. de Pasquale S. Ciuchi

We apply the Dynamical Mean Field Theory to calculate the low-density limit of the optical conductivity in the Holstein model. This non perturbative treatment allows to span continuously from the weak-coupling quasi-free electron behaviour to the strong-coupling small polaron picture. New features arise in the intermediate coupling regime: i) a noticeable tr

Hal Tasaki

In a macroscopic (quantum or classical) Hamiltonian system, we prove the second law of thermodynamics in the forms of the minimum work principle and the law of entropy increase, under the assumption that the initial state is described by a general equilibrium distribution. Therefore the second law is a logical necessity once we accept equilibrium statistical

M. J. Drinkwater, M. D. Gregg, M. Colless

We present the first dynamical analysis of a galaxy cluster to include a large fraction of dwarf galaxies. Our sample of 108 Fornax Cluster members measured with the UK Schmidt Telescope FLAIR-II spectrograph contains 55 dwarf galaxies (15.5>bj>18.0 or -16>Mb>-13.5). Halpha emission shows that 36+/-8 per cent of the dwarfs are star-forming, twice the fractio

Ravi Sankrit, R. L. Shelton, W. P. Blair, K. R. Sembach

We present the results of a FUSE observation of an X-ray selected knot in the Vela supernova remnant. Spectra were obtained through the 30"x30" low resolution aperture and the 4"x20" medium resolution aperture. O VI 1032,1038 and C III 977 are detected strongly in both spectra, and S VI 933,944 is detected weakly only in the larger aperture s

A. Lancon

Age dating starbursts is an exercise with many caveats. We attempt to summarise a discussion session that was lead along a rather optimistic guideline: the aim was to highlight that current age estimates, despite undeniable uncertainties, do provide constraints on the physics of starbursts. In many cases, better starburst theories will be needed before the i

M. Ostrowski, E. Fürst

The energy ejected from the galaxy micro-quasar GRS1915+105 in the form of jets is expected to lead to formation of an extended double lobe/hot-spot structure with the energy content comparable to an average supernova remnant. We used the Effelsberg 100m telescope at 10.45 GHz in attempt to identify such structures. For this distant galactic plane source any

A. Lancon, M. Mouhcine

The efficient use of near-IR data in studies of external stellar populations depends on our ability to recognize the nature of the predominant sources of light, and to interprete these findings in terms of age and metallicity. Here we focus on elderly post-starburst populations, with ages of 0.1-1 Gyr. New models confirm that they are indeed expected to disp

Ofer Lahav

Methods for compression and classification of galaxy spectra, which are useful for large galaxy redshift surveys (such as the SDSS, 2dF, 6dF and VIRMOS), are reviewed. In particular, we describe and contrast three methods: (i) Principal Component Analysis, (ii) Information Bottleneck, and (iii) Fisher Matrix. We show applications to 2dF galaxy spectra and to

Marc Sarzi, Hans-Walter Rix, Joseph C. Shields, Greg Rudnick

We report three new accurate mass measurements for the supermassive black holes hosted by the early-type disk galaxies NGC2787, NGC4459 and NGC4596. The targets were selected from a larger set of long-slit spectra obtained with the Hubble Space Telescope as part of the Survey of Nearby Nuclei with STIS (SUNNS). They display symmetric gas velocity curves that

David Fosse, Jose Cernicharo, Maryvonne Gerin, Pierre Cox

We present mapping results in several rotational transitions of HC3N, C6H, both cyclic and linear C3H2 and C3H, towards the cyanopolyyne peak of the filamentary dense cloud TMC-1 using the IRAM 30m and MPIfR 100m telescopes. The spatial distribution of the cumulene carbon chain propadienylidene H2C3 (hereafter l-C3H2) is found to deviate significantly from t

Torsten A. Ensslin, Patrick Simon, Peter L. Biermann, Ulrich Klein

Sensitive images of low-level, Mpc-sized radio cocoons offer new opportunities to probe large scale intergalactic gas flows outside clusters of galaxies. New radio images of high surface brightness sensitivity at strategically chosen wavelengths of the giant radio galaxy NGC 315 (Mack et al. 1997,1998) reveal significant asymmetries and particularities in th

Daniel Schaerer

We review the main stellar features observed in starburst spectra from the UV to the near-IR and their use as fundamental tools to determine the properties of stellar populations from integrated spectra. The origin and dependence of the features on stellar properties are discussed, and we summarise existing modeling techniques used for quantitative analysis.

Rainer Beck

The current state of research of the Galactic magnetic field is reviewed critically. The average (equipartition) strength of the total field derived from radio synchrotron data is 6 +/- 2 muG locally and about 10 +/- 3 muG at 3 kpc Galactic radius. These values agree well with the estimates using the locally measured cosmic-ray energy spectrum and the radial

HEGRA Collaboration, F. Aharonian

For distant extragalactic sources of gamma-rays in the PeV energy range, interactions of the gamma rays with intergalactic diffuse radiation fields will initiate a pair cascade. Depending on the magnetic fields in the vicinity of the source, the cascade can either result in an isotropic halo around an initially beamed source, or remain more or less collimate

Robert E. Rutledge, Lars Bildsten, Edward F. Brown, George G. Pavlov

We report on spectral and intensity variability analysis from a Chandra/ACIS-S observation of the transient, type-I X-ray bursting low-mass X-ray binary Cen X-4. The quiescent X-ray spectrum during this observation is statistically identical to one observed previously with Beppo/SAX, and close, but not identical, to one observed previously with ASCA. The X-r

E. Aprile, U. G. Oberlack, A. Curioni, V. Egorov

LXeGRIT is a balloon-borne Compton telescope employing a large volume liquid xenon time projection chamber (LXeTPC) as the central gamma-ray detector. It is designed to image gamma rays in the energy range of 200 keV to 20 MeV, with an angular resolution of about 3 degrees (1 sigma) at 2 MeV, within a field-of-view (FOV) of about 1 sr. The detector's ene

G. Soucail, J. P. Kneib, A. O. Jaunsen, J. Hjorth

We present new optical data on the cluster AX J2019+1127 identified by the X-ray satellite ASCA at z\sim 1 (Hattori et al. 1997). The data suggest the presence of a high-redshift cluster of galaxies responsible for the large separation triple quasar MG2016+112. Our deep photometry reveals an excess of z\sim 1 galaxy candidates, as already suspected by Benite

Joel E. Moore, A. Zee, Jairo Sinova

The localization behavior of noninteracting two-dimensional electrons in a random potential and strong magnetic field is of fundamental interest for the physics of the quantum Hall effect. In order to understand the emergence of power-law delocalization near the discrete extended-state energies $E_n = \hbar ω_c (n+{1/2})$, we study a generalization of the di

Csaba Csaki, Joshua Erlich, Christophe Grojean

We investigate spacetimes in which the speed of light along flat 4D sections varies over the extra dimensions due to different warp factors for the space and the time coordinates (``asymmetrically warped'' spacetimes). The main property of such spaces is that while the induced metric is flat, implying Lorentz invariant particle physics on a brane, bu

J. E. Pask, D. J. Singh, I. I. Mazin, C. S. Hellberg

We calculate the structural, electronic, and magnetic properties of MnO from first principles, using the full-potential linearized augmented planewave method, with both local-density and generalized-gradient approximations to exchange and correlation. We find the ground state to be of rhombohedrally distorted B1 structure with compression along the [111] dir

L. Berger

In metallic ferromagnets, an electric current is accompanied by a flux of angula r momentum, also called spin current. In multilayers, spatial variations of the spin current correspond to drive torques exerted on a magnetic layer. These torq ues result in spin precession above a certain current threshold. The usual kind of spin current is associated with tra

E. Xanthopoulos, A. M. S. Richards

MERLIN images of Mrk 348 at 22 GHz show water maser emission at 0.02 - 0.11 Jy, within approximately 0.8 pc of the nucleus. This is the first direct confirmation that molecular material exists close to the Seyfert 2 nucleus. Mrk 348 was observed in 2000 May one month after Falcke et al. (2000) first identified the maser in single-dish spectra. The peak maser

Steven S. Gubser, Mukund Rangamani

We study the recently proposed D-brane configuration [hep-th/0010105] modeling the quantum Hall effect, focusing on the nature of the interactions between the charged particles. Our analysis indicates that the interaction is repulsive, which it should be for the ground state of the system to behave as a quantum Hall liquid. The strength of interactions varie

Jonathan Bagger, Dennis Nemeschansky, Ren-Jie Zhang

We derive the effective action for the radion supermultiplet in the supersymmetric Randall-Sundrum model with two opposite tension branes.

Enrico Ramirez-Ruiz, Lynnette M. Dray, Piero Madau, Christopher A. Tout

Recent observations suggest that long-duration gamma-ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in core-collapse explosions. The pre-explosive ambient medium provides a natural test for the most likely progenitors of GRBs. Those stars that shed their envelopes most readily have short jet crossing times and are mor

Michael Meyer-Hermann, Ralf Kuhn, Ralf Schützhold

We show that a standard calculation of the splitting function for the nonsinglet structure function h_1 does not lead to the expected result. The calculation is compared to the corresponding derivation of the splitting function for the nonsinglet polarized structure function g_1. We analyze possible explanations for the unexpected result and discuss its impl

Anne M Green

Weakly Interacting Massive Particle (WIMP) direct detection event rate calculations usually rely on fairly simple, essentially static, analytic halo models. This is largely since the resolution of numerical simulations is not yet large enough to allow the full numerical calculation of the WIMP density and velocity distribution. In this paper we study the dir

A. D. Martin, J. Outhwaite, M. G. Ryskin

The standard determination of the QED coupling on the Z pole is performed using the latest available data for R. The direct application of analytic continuation techniques is found not to improve the accuracy of the value of α(M_Z^2). However they help to resolve an ambiguity in the values of R in the energy region \sqrt{s} < 2 GeV, which, in turn, reduces t

John Schliemann, J. Ignacio Cirac, Marek Kus, Maciej Lewenstein

We characterize and classify quantum correlations in two-fermion systems having 2K single-particle states. For pure states we introduce the Slater decomposition and rank (in analogy to Schmidt decomposition and rank), i.e. we decompose the state into a combination of elementary Slater determinants formed by mutually orthogonal single-particle states. Mixed s

Paul M. Fishbane, Stephen G. Gasiorowicz

We study the dynamical equations for two-family neutrino oscillations in a medium of continuously-varying density. We can find explicit solutions to these equations in terms of series of nested integrals. These solutions can serve as a basis for numerical calculation of these processes or for further study of their analytical properties.

M. Fabbrichesi, M. Piai, G. Tasinato

Whenever fields are allowed to propagate in different portions of space-time, the four dimensional theory exhibits an effective violation of the principle of equivalence. We discuss the conditions under which such an effect is relevant for neutrino physics. In the simplest case of compactification on a flat manifold, the effect of gravity is many orders of m

J. C. Nacher, E. Oset, M. J. Vicente Vacas, L. Roca

Recent information on invariant mass distributions of the $γp\toπ^+π^0 n$ reaction, where previous theoretical models had shown deficiencies, have made more evident the need for new mechanisms, so far neglected or inaccurately included. We have updated a previous model to include new necessary mechanisms. We find that the production of the $ρ$ meson, and the

Ralph Blumenhagen, Volker Braun, Robert Helling

We discuss some issues related to D(2p)-D0 branes with background magnetic fluxes respectively, in a T-dual picture, Dp-Dp branes at angles. In particular, we describe the nature of the supersymmetric bound states appearing after tachyon condensation. We present a very elementary derivation of the conditions to be satisfied by such general supersymmetric gau

L. Hoffmann, L. Mesref, W. Ruehl

Operator product expansions are applied to dilaton-axion four-point functions. In the expansions of the bilocal fields $\tildeΦ\tildeΦ$, $\tilde{C}\tilde{C}$ and $\tildeΦ\tilde{C}$, the conformal fields which are symmetric traceless tensors of rank $l$ and have dimensions $δ=2+l$ or $8+l+η(l)$ and $η(l)=\mathcal{O}(N^{-2})$ are identified. The unidentified f

Martin Beneke, Alexander Lenz

We give an update on the lifetime difference of $B_s$ mesons which accounts for recent lattice bag parameter results, and obtain $(ΔΓ/Γ)_{B_s}=(9.3^{+3.4}_{-4.6})%$. We then review the current theoretical uncertainties and conclude with a pessimistic perspective on further improvements.

Y. Kanazawa, Yuji Koike

Polarization of the Λhyperon produced with a large transverse momentum in the unpolarized nucleon-nucleon collision is analyzed in the framework of QCD factorization. We focus on the mechanism in which the soft-gluon component of the chiral-odd spin-independent twist-3 quark distribution E_F(x,x) becomes a source of the polarized quark fragmenting into the p

Malek Bou-Diab, Matthew J. W. Dodgson, Gianni Blatter

We investigate the collision of two vortex lines moving with viscous dynamics and driven towards each other by an applied current. Using London theory in the approach phase we observe a non-trivial vortex conformation producing anti-parallel segments; their attractive interaction triggers a violent collision. The collision region is analyzed using the time-d

A. Bernert, T. Chatterji, P. Thalmeier, P. Fulde

We report results of a new analysis for the low-temperature structure of alpha&#39;-NaV2O5 from synchrotron x-ray diffraction experiments. We confirm the existence of two inequivalent ladder structures in each vanadium layer. Based on our structural data we perform a bond-valence calculation for the vanadium sites in the low temperature state. Due to an asym

E. Elizalde

Explicit formulas for the zeta functions $ζ_α(s)$ corresponding to bosonic ($α=2$) and to fermionic ($α=3$) quantum fields living on a noncommutative, partially toroidal spacetime are derived. Formulas for the most general case of the zeta function associated to a quadratic+linear+constant form (in {\bf Z}) are obtained. They provide the analytical continuat

Stephen C. Davis, Warren B. Perkins, Anne-Christine Davis, Ian R. Vernon

In brane world scenarios the Friedmann equation is modified, resulting in an increased expansion at early times. This has important effects on cosmological phase transitions which we investigate, elucidating significant differences to the standard case. First order phase transitions require a higher nucleation rate to complete; baryogenesis and particle abun

P. Braun-Munzinger, J. Stachel

We discuss aspects of the statistical hadronization model for the production of mesons with open and hidden charm in ultra-relativistic nuclear collisions. Emphasis is placed on what can be inferred from the dependence of the yield of charmonia on the number of participants in the collisions.

Yukito Iba

``Extended Ensemble Monte Carlo&#39;&#39;is a generic term that indicates a set of algorithms which are now popular in a variety of fields in physics and statistical information processing. Exchange Monte Carlo (Metropolis-Coupled Chain, Parallel Tempering), Simulated Tempering (Expanded Ensemble Monte Carlo), and Multicanonical Monte Carlo (Adaptive Umbrell

W. Son, Jinhyoung Lee, M. S. Kim, Y. -J. Park

We formulate a conclusive teleportation protocol for a system in d-dimensional Hilbert space utilizing the positive operator valued measurement at the sending station. The conclusive teleportation protocol ensures some perfect teleportation events when the channel is only partially entangled, at the expense of lowering the overall average fidelity. We find t

Isard Dunietz, Robert Fleischer, Ulrich Nierste

The presence of a sizeable CP-violating phase in B_s^0-B_s^0-bar mixing would be an unambiguous signal of physics beyond the Standard Model. We analyse various possibilities to detect such a new phase considering both tagged and untagged decays. The effects of a sizeable width difference Delta Gamma between the B_s mass eigenstates, on which the untagged ana

Kim Hyeon-Deuk, Hisao Hayakawa

The inelastic Lorentz gas in cooling states is studied. It is found that the inelastic Lorentz gas is localized and that the mean square displacement of the inelastic Lorentz gas obeys a power of a logarithmic function of time. It is also found that the scaled position distribution of the inelastic Lorentz gas has an exponential tail, while the distribution

Z. Xiong, J. -M. Yang

We examine the rare decays $B\to X_sτ^+τ^-$ and $B_s\toτ^+τ^- γ$ in the framework of technicolor with scalars. The contributions from both the neutral and charged scalars predicted in this model are evaluated. We find that the branching ratios could be enhanced over the standard model predictions by a couple of orders of magnitude in some part of parameter s

Achille Stocchi

In this note I review the current determination of the unitarity triangle parameters by using the theoretical and experimental information available in summer 2000.