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February 2000 arXiv papers — page 18

Showing 1,701–1,800 of 2,343 papers

  1. T. Ohgaki

    We demonstrate a measurement of the Higgs boson mass by the method of energy scanning at photon-photon colliders, using the high energy edge of the photon spectrum. With an integrated luminosity of 50 $\rm{fb^{-1}}$ it is possible to measure the standard model Higgs mass to within 110 MeV in photon-photon collisions for m_h=100 GeV. As for the total width of

  2. C. Boros, J. T. Londergan, A. W. Thomas

    We discuss Lambda polarization in semi-inclusive proton-proton collisions, with one of the protons longitudinally polarized. The hyperfine interaction responsible for the $\Delta$-$N$ and $\Sigma$-$\Lambda$ mass splittings gives rise to flavor asymmetric fragmentation functions and to sizable polarized non-strange fragmentation functions. We predict large po

  3. D. Yu. Peressounko, Yu. E. Pokrovsky

    On the basis of hydrodynamic model of evolution we consider emission of lightest (π,K,η,ρ,ω,K^*) mesons directly from the surface of quark-gluon plasma, created in the heavy ion collision, with accounting of their absorption by surrounding hadronic gas. We evaluate upper and lower limits on yields of these direct mesons in Pb+Pb collisions at SpS, RHIC and L

  4. DELPHI Collaboration, P. Abreu

    An updated analysis using about 1.5 million events recorded at $\sqrt{s} = M_Z$ with the DELPHI detector in 1994 is presented. Eighteen infrared and collinear safe event shape observables are measured as a function of the polar angle of the thrust axis. The data are compared to theoretical calculations in ${\cal O} (α_s^2)$ including the event orientation. A

  5. The OPAL collaboration, G. Abbiendi

    The cross-section ratio Rb=sigma(e+e- to b-antib)/sigma(e+e- to q-antiq) and the bottom and charm forward-backward asymmetries AFB^b and AFB^c are measured using event samples collected by the OPAL detector at centre-of-mass energies between 130 and 189 GeV. Events with bottom quark production are selected with a secondary vertex tag, and a hemisphere charge

  6. L P Grishchuk

    The range of expected amplitudes and spectral slopes of relic (squeezed) gravitational waves, predicted by theory and partially supported by observations, is within the reach of sensitive gravity-wave detectors. In the most favorable case, the detection of relic gravitational waves can be achieved by the cross-correlation of outputs of the initial laser inte

  7. P. Bizoń, A. Wasserman

    We prove the existence of a countable family of globally regular solutions of spherically symmetric Einstein-Klein-Gordon equations. These solutions, known as mini-boson stars, were discovered numerically many years ago.

  8. Pradosh Kumar Mohapatra

    In this paper, we present a fully-dynamic distributed algorithm for maintaining a minimum spanning tree on general graphs with positive real edge weights. The goal of a dynamic MST algorithm is to update efficiently the minimum spanning tree after dynamic changes like edge weight changes, rather than having to recompute it from scatch each time. The first pa

  9. Yu. Zadorozhny, D. R. Herman, Y. Liu

    Reproducible, sample-specific magnetoresistance fluctuations (magnetic fingerprints) have been observed experimentally in the low-temperature part of the superconducting transition regime of disordered superconducting Au_0.7In_0.3 cylinders. The amplitude of the fluctuation was found to exceed that of the universal conductance fluctuation in normal metals by

  10. A. Yu. Cherny

    Pair wave functions (PWF) which are eigenfunctions of the reduced density 2-matrix are considered for a homogeneous Bose liquid. With the Bogoliubov principle of the correlation weakening it is proved that the distribution of the "dissociated" pair states over momenta is exactly the product of the single-particle distribution functions. Thus, the &#3

  11. A. B. Kuklov

    It is shown that the interconversion mechanism for the triplet excitons in Cu_2O suggested recently by G.M. Kavoulakis and A. Mysyrowicz in cond-mat/0001438 can be tested by the two-photon direct creation of the triplet excitons.

  12. Marek Trippenbach, Yehuda B. Band, Paul S. Julienne

    A recent experiment [Deng et al., Nature 398, 218(1999)] demonstrated four-wave mixing of matter wavepackets created from a Bose-Einstein condensate. The experiment utilized light pulses to create two high-momentum wavepackets via Bragg diffraction from a stationary Bose-Einstein condensate. The high-momentum components and the initial low momentum condensat

  13. Hao-wen Xi, Raul Toral, J. D. Gunton, Michael I. Tribelsky

    We carry out a systematic study of a novel type of chaos at onset ("soft-mode turbulence") based on numerical integration of the simplest one dimensional model. The chaos is characterized by a smooth interplay of different spatial scales, with defect generation being unimportant. The Lyapunov exponents are calculated for several system sizes for fixe

  14. Amos Maritan, Cristian Micheletti, Jayanth R. Banavar

    A fascinating and open question challenging biochemistry, physics and even geometry is the presence of highly regular motifs such as alpha-helices in the folded state of biopolymers and proteins. Stimulating explanations ranging from chemical propensity to simple geometrical reasoning have been invoked to rationalize the existence of such secondary structure

  15. Tulika Maitra

    In view of the current interest in d_{x^{2}-y^{2}}+id_{xy} superconductors some of their thermodynamic properties have been studied to obtain relevant information for experimental verification. The temperature dependence of the specific heat and superfluid density show marked differences in d_{x^{2}-y^{2}}+id_{xy} state compared to the pure d-wave state. A s

  16. Toru Sakai, Nobuhisa Okazaki

    The magnetic properties of the antiferromagnetic spin ladder with the next-nearest neighbor interaction, particularly under external field, are investigated by the exact diagonalization of the finite clusters and size scaling techniques. It is found that there exist two phases, the rung-dimer and rung-triplet phases, not only in the nonmagnetic ground state

  17. P. G. Kealey, T. M. Riseman, E. M. Forgan, L. M. Galvin

    We have measured the diffracted neutron scattering intensities from the square magnetic flux lattice in the perovskite superconductor Sr$_2$RuO$_4$, which is thought to exhibit p-wave pairing with a two-component order parameter. The relative intensities of different Bragg reflections over a wide range of field and temperature have been shown to be inconsist

  18. J. C. Martinez, A. Schattke, G. Jakob, H. Adrian

    The coupling between the superconducting planes of YBa2Cu3O{7-δ}/ PrBa2Cu3O{7-δ} superlattices has been measured by c-axis transport. We show that only by changing the thickness of the superconducting YBa2Cu3O{7-δ} layers, it is possible to switch between quasi-particle and Josephson tunneling. From our data we deduce a low temperature c-axis coherence lengt

  19. I. Galanakis, M. Alouani, H. Dreyssé

    We have performed a theoretical study of the magnetic circular dichroism in the x-ray absorption spectra (XMCD) of the equiatomic CoPt and FePt ordered alloys as a function of the spin quantization axis. We found that the magnetization axis is along the [001] direction and the magneto-crystalline anisotropy energy (MCA) for the FePt compound is twice as larg

  20. D. E. Feldman

    The paper contains a rigorous proof of the absence of quasi-long-range order in the random-field O(N) model for strong disorder in the space of an arbitrary dimensionality. This result implies that quasi-long-range order inherent to the Bragg glass phase of the vortex system in disordered superconductors is absent as the disorder or external magnetic field i

  21. Y. G. Joh, R. Orbach, G. G. Wood, J. Hammann

    The recent identification of a time and temperature dependent spin glass correlation length, $ξ({t_w},T)$, has consequences for samples of finite size. Qualitative arguments are given on this basis for departures from t/{t_w} scaling for the time decay of the thermoremanent magnetization, {M_{TRM}}(t,{t_w},T), where t is the measurement time after a ``waitin

  22. D. R. Lorimer, M. Kramer, P. Mueller, N. Wex

    We have used the Effelsberg 100-m radio telescope to conduct a 1400-MHz ($λ$ 21-cm) search for young and rapidly rotating radio pulsars along a 2 deg$^2$ strip of the northern Galactic plane defined by $28^{\circ} \leq l \leq 30^{\circ}$ and $|b|\leq0.5^{\circ}$. This region lies close to the Scutum spiral arm which is already known to contain a number of ra

  23. Raymundo Baptista, C. Silveira, J. E. Steiner, Keith Horne

    Time-resolved spectroscopy of the novalike variable UU Aquarii is analyzed with eclipse mapping techniques to produce spatially resolved spectra of its accretion disc and gas stream as a function of distance from disc centre in the range 3600-6900 Å. The spatially-resolved spectra show that the continuum emission becomes progressively fainter and redder for

  24. Alan H. Guth

    The basic workings of inflationary models are summarized, along with the arguments that strongly suggest that our universe is the product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal

  25. Raymundo Baptista, E. Harlaftis, D. Steeghs

    Eclipse lightcurves of the dwarf nova IP Peg during the November 1996 outburst are analysed with eclipse mapping techniques to constrain the location and investigate the spatial structure of the spiral shocks observed in the Doppler tomograms (Harlaftis et al. 1999). Eclipse maps in the blue continuum and in the CIII+NIII 4650 emission line show two asymmetr

  26. C. L. Carilli, G. B. Taylor

    Images of neutral Hydrogen 21cm absorption and radio continuum emission at 1.4 GHz from Mrk 273 were made using the Very Long Baseline Array and Very Large Array. These images reveal a gas disk associated with the northern nuclear region with a diameter of 0.5'' (370 pc), at an inclination angle of 53deg. The radio continuum emission is composed of a

  27. D. J. Burke, C. A. Collins, R. G. Mann

    The K-band Hubble diagram of Brightest Cluster Galaxies (BCGs) is presented for a large, X-ray selected cluster sample extending out to z = 0.8. The controversy over the degree of BCG evolution is shown to be due to sample selection, since the BCG luminosity depends upon the cluster environment. Selecting only the most X-ray luminous clusters produces a BCG

  28. Reinhard Genzel, Catherine J. Cesarsky

    More than a decade ago the IRAS satellite opened the realm of external galaxies for studies in the 10 to 100 micron band and discovered emission from tens of thousands of normal and active galaxies. With the 1995-1998 mission of the Infrared Space Observatory the next major steps in extragalactic infrared astronomy became possible: detailed imaging, spectros

  29. S. Cassisi, V. Castellani, S. Degl'Innocenti G. Fiorentini, B. Ricci

    We discuss in detail the information on large extra dimensions which can be derived in the framework of stellar evolution theory and observation. The main effect of large extra dimensions arises from the production of the Kaluza-Klein (KK) excitations of the graviton. The KK-graviton and matter interactions are of gravitational strength, so the KK states nev

  30. Ersin Gogus, Peter M. Woods, Chryssa Kouveliotou, Jan van Paradijs

    We present statistics of SGR 1806-20 bursts, combining 290 events detected with RXTE/PCA, 111 events detected with BATSE and 134 events detected with ICE. We find that the fluence distribution of bursts observed with each instrument are well described by power laws with indices 1.43, 1.76 and 1.67, respectively. The distribution of time intervals between suc

  31. R. C. Kennicutt,, F. Bresolin, H. French, P. Martin

    We present spectrophotometry in the 3600-9700 A region for a sample of 39 H II regions in the Galaxy and Magellanic Clouds, for which independent information is available on the spectral types and effective temperatures of the ionizing stars. The spectra have been used to evaluate nebular diagnostics of stellar temperature, metal abundance, and ionization pa

  32. C. N. Tadhunter, W. Sparks, D. J. Axon, L. Bergeron

    We present near-IR imaging polarimetry observations of the nucleus of Cygnus A, taken with the NICMOS camera of the HST at a wavelength of 2.0 microns.These maps reveal a highly collimated region of polarized emission straddling the nucleus and extending to a radius of 1.2 arcseconds. Remarkably, this feature coincides with one, but only one, limb of the edg

  33. T. Lu

    There have been great and rapid progresses in the field of $γ$-ray bursts (denoted as GRBs) since BeppoSAX and other telescopes discovered their afterglows in 1997. Here, we will first give a brief review on the observational facts of GRBs and direct understanding from these facts, which lead to the standard fireball model. The dynamical evolution of the fir

  34. Jonathan Braine, Ute Lisenfeld, Pierre-Alain Duc, Stephane Leon

    In many gravitational interactions between galaxies, gas and stars that have been torn from either or both of the precursor galaxies can collect in 'tidal tails'. Star formation begins anew in these regions to produce 'tidal dwarf galaxies', giving insight into the process of galaxy formation through the well-defined timescale of the interact

  35. Axel W. Guthmann, John G. Kirk, Yves A. Gallant, Abraham Achterberg

    We adapt and modify the eigenfunction method of computing the power-law spectrum of particles accelerated at a relativistic shock front via the first-order Fermi process (Kirk, J.G., Schneider, P., Astrophysical Journal 315, 425 (1987)) to apply to shocks of arbitrarily high Lorentz factor. The power-law index of accelerated particles undergoing isotropic sm

  36. C. N. Tadhunter, M. Villar-Martin, R. Morganti, J. Bland-Hawthorn

    Deep, narrow-band Halpha observations taken with the TAURUS Tunable Filter (TTF) on the 4.2m WHT telescope are presented for two nearby radio galaxies with strong jet-cloud interactions. Although the brightest emission line components are closely aligned with the radio jets --- providing nearby examples of the ``alignment effect'' most commonly obser

  37. Slavek M. Rucinski, Wenxian Lu, Stefan W. Mochnacki

    Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the third set of ten contact binary systems: CN And, HV Aqr, AO Cam, YY CrB, FU Dra, RZ Dra, UX Eri, RT LMi, V753 Mon, OU Ser. All systems but two are contact, double-line spectroscopic binaries with four of them (YY CrB, FU Dra, V753 Mon, OU Ser) bei

  38. B. V. Vasiliev

    The calculations in Thomas-Fermi approximation show that in a gravitational field each cell of ultra dense matter inside celestial bodies obtains a very small positive electric charge. A celestial body is electrically neutral as a whole, because the negative electric charge exists at its surface. The positive volume charge is very small, on the order of magn

  39. G. Risaliti, R. Maiolino, L. Bassani

    We present BeppoSAX observations of the Seyfert 1.8 galaxy NGC1365 in the 0.1--100 keV range. The source was 6 times brighter than during an ASCA observation 3 years earlier. The 4--10 keV flux is highly variable during the BeppoSAX observation, while the soft (0.1-4 keV) emission is constant within the errors. Both a cold and a warm reflector and a cold abs

  40. S. R. Kulkarni, E. Berger, J. S. Bloom, F. Chaffee

    Gamma-ray burst astronomy has undergone a revolution in the last three years, spurred by the discovery of fading long-wavelength counterparts. We now know that at least the long duration GRBs lie at cosmological distances with estimated electromagnetic energy release of 10**51 -- 10**53 erg, making these the brightest explosions in the Universe. In this arti

  41. Jun Yokogawa, Kensuke Imanishi, Masahiro Tsujimoto, Mamiko Nishiuchi

    The Advanced Satellite for Cosmology and Astrophysics (ASCA) has made multiple observations of the Small Magellanic Cloud (SMC). X-ray mosaic images in the soft (0.7--2.0 keV) and hard (2.0--7.0 keV) bands are separately constructed, and the latter provides the first hard X-ray view of the SMC. We extract 39 sources from the two-band images with a criterion

  42. Re'em Sari

    The origin of GRBs have been a mystery for almost 30 years. The afterglow observed in the last few years enabled redshift determination for a handful of bursts, and the cosmological origin is now firmly established. Though the distance scale is settled, there still remains orders of magnitude uncertainty in their rate and in the total energy that is released

  43. Evan Scannapieco

    The dominant linear contribution to cosmic microwave background (CMB) fluctuations at small angular scales (less than one arcsec) is a second-order contribution known as the Vishniac or Ostriker-Vishniac effect. This effect is caused by the scattering of CMB photons off free electrons after the universe has been reionized, and is dominated by linear perturba

  44. Lloyd Knox

    The inflation-inspired flat, cold dark matter-dominated models of structure formation with adiabatic, nearly scale-invariant initial conditions agree very well with current CMB anisotropy data. The success of these models is highlighted by the failure of alternatives; we argue that there are no longer any viable competitors (with the exception of models with

  45. Lloyd Knox, Lyman Page

    A peak has been unambiguously detected in the cosmic microwave background (CMB) angular spectrum. Here we characterize its properties with fits to phenomenological models. We find that the TOCO and BOOM/NA data determine the peak location to be in the range 175--243 and 151--259 respectively (both ranges 95% confidence) and determine the peak amplitude to be

  46. Tom Abel, Zoltan Haiman

    We review the relevance of H2 molecules for structure formation in cosmology. Molecules are important at high redshifts, when the first collapsed structures appear with typical temperatures of a few hundred Kelvin. In these chemically pristine clouds, radiative cooling is dominated H2 molecules. As a result, H2 ``astro-chemistry'' is likely to determ

  47. Sergio De Filippo

    Only craziness I am ashamed about.

  48. Nathan Roche, James Lowenthal, Bruce Woodgate

    We investigate a very luminous Lyman-alpha emitting galaxy, associated with a z=2.3 damped absorption system in the spectrum of the QSO PHL 957. The galaxy was observed with the HST WFPC2, through a narrow filter (F410M) corresponding to rest-frame Lyman -alpha, for 41.2 ksec, with shorter exposures in F555W and F814W. The galaxy is resolved into a close (0.

  49. M. Cvetic, H. Lu, C. N. Pope, A. Sadrzadeh

    In a recent paper, the complete (non-linear) Kaluza-Klein Ansatz for the consistent embedding of certain scalar plus gravity subsectors of gauged maximal supergravity in D=4, 5 and 7 was presented, in terms of sphere reductions from D=11 or type IIB supergravity. The scalar fields included in the truncations were the diagonal fields in the SL(N,R)/SO(N) scal

  50. Prasanta Das, Sreerup Raychaudhuri, Saswati Sarkar

    We study recent data on deep inelastic e^+ p scattering at HERA to constrain the parameters of a Randall-Sundrum-type scenario of quantum gravity with a small extra dimension and a non-factorable geometry.

  51. N. A. Patel, L. J. Greenhill, J. Herrnstein, Q. Zhang

    We present VLBA observations of water maser emission associated with the star-forming region IRAS 21391+5802, which is embedded in a bright rimmed cometary globule in IC1396. The angular resolution of the maps is about 0.8 mas, corresponding to a spatial resolution of about 0.6 AU, at an estimated distance of 750 pc. Proper motions are derived for 10 maser f

  52. M. A. Anacleto, J. R. S. Nascimento, R. F. Ribeiro

    In this paper we investigated the dynamics, at the quantum level, of the self-dual field minimally coupled to bosons. In this investigation we use the Dirac bracket quantization procedure to quantize the model. Also, the relativistic invariance is tested in connection with the elastic boson-boson scattering amplitudes.

  53. J. S. Arellano, L. M. Molina, A. Rubio, J. A. Alonso

    Density functional theory has been used to study the adsorption of molecular H2 on a graphene layer. Different adsorption sites on top of atoms, bonds and the center of carbon hexagons have been considered and compared. We conclude that the most stable configuration of H2 is physisorbed above the center of an hexagon. Barriers for classical diffusion are, ho

  54. Ph. Hagler, R. Kirschner, A. Schafer, L. Szymanowski

    QCD dynamics at small quark and gluon momentum fractions or large total energy, which plays a major role for HERA, the Tevatron, RHIC and LHC physics, is still poorly understood. For one of the simplest processes, namely bottom-antibottom production, next-to-leading-order perturbation theory fails. We show that the combination of two recently developed theor

  55. Juan Garcia-Bellido, Silvia Mollerach, Esteban Roulet

    At the end of inflation, the coherent oscillations of the inflaton field may resonantly amplify the long wavelength modes of both bosons and fermions coupled to it. We study the resonant production of both kinds of particles during preheating in a model of hybrid inflation. The coherent time evolution of the inflaton and the Higgs fields after inflation indu

  56. Nora Brambilla, Antonio Vairo

    We evaluate in perturbative QCD, up to order $α_s^4$, the mass of the $B_c$. We use the so-called 1S-mass in order to improve the convergence of the perturbative series. Our result is $E(B_c)_{pert} = 6326^{+29}_{-9}$ MeV. Non-perturbative effects are discussed. A comparison with potential models seems to be consistent with non-perturbative contributions of

  57. M. Dima

    Flash-algorithm track-reconstruction routines with speed factors 3000-4000 in excess those of traditional iterative routines are presented. The methods were successfully tested in the alignment of the Test Beam setup for the ATLAS Pixel Detector MCM-D modules yielding a 60 fold increase in alignment resolution over iterative routines, for the same amount of

  58. E. M. de Gouveia Dal Pino, A. Lazarian

    We here investigate the possibility that the ultra-high energy cosmic ray (UHECR) events observed above the GZK limit are mostly protons accelerated in reconnection sites just above the magnetosphere of newborn millisecond pulsars which are originated by accretion induced collapse (AIC). We show that AIC-pulsars with surface magnetic fields $10^{12} G < B_{\

  59. P. P. Avelino, J. P. M. de Carvalho, C. J. A. P. Martins

    We re-analyze the question of the use of cosmological observations to infer the present state and future evolution of our patch of the universe. In particular, we discuss under which conditions one might be able to infer that our patch will enter an inflationary stage, as a prima facie interpretation of the Type Ia supernovae and CMB data would suggest. We t

  60. Andreas S. Kronfeld

    Heavy-quark effective theory (HQET) is applied to lattice QCD with Wilson fermions at fixed lattice spacing a. This description is possible because heavy-quark symmetries are respected. It is desirable because the ultraviolet cutoff $1/a$ in current numerical work and the heavy-quark mass $m_Q$ are comparable. Effects of both short distances, a and $1/m_Q$,

  61. Sher Alam, Kaoru Hagiwara, Shinya Kanemura, Robert Szalapski

    We study one-loop effects of sfermions on helicity amplitudes for $\eeww$ in the Minimal Supersymmetric Standard Model. The one-loop contributions are calculated in the $\bar{\rm MS}$ renormalization scheme. In order to verify the validity of the analytic calculation and the numerical program, the following tests are performed. (i) The BRS sum rules hold exa

  62. Andre de Gouvea, Alexander Friedland, Hitoshi Murayama

    Results of neutrino oscillation experiments have always been presented on the (sin^2 2theta, Delta m^2) parameter space for the case of two-flavor oscillations. We point out, however, that this parameterization misses the half of the parameter space pi/4 < theta <= pi/2 (``the dark side&#39;&#39;), which is physically inequivalent to the region 0 <= theta <=

  63. C. N. Leung

    We review the status of testing the principle of equivalence and Lorentz invariance from atmospheric and solar neutrino experiments.

  64. Cesar Gomez, Bert Janssen, Pedro Silva

    We extend Randall-Sundrum dynamics to non-conformal metrics corresponding to non-constant dilaton. We study the appareance of space-time naked singularities and the renormalization group evolution of four-dimensional Newton constant.

  65. Johannes Blümlein, Dieter Robaschik

    A systematic study is performed of the structure of the twist-2 contributions to the virtual Compton amplitude in deep-inelastic non-forward scattering for general spin states in the non-local light cone expansion. The gauge invariance is proven in this approach for the twist-2 contributions for non-forward scattering. Relations are derived between the contr

  66. Hanno Essen

    The importance of the Darwin-Breit interaction between electrons in solids at low temperatures is investigated. The model problem of particles on a circle is used and applied to mesoscopic metal rings in their normal state. The London moment formula for a rotating superconducting sphere is used to calculate the number, $N$, of superconducting electrons on th

  67. C. Giunti, M. Laveder

    We define some appropriate statistical quantities that indicate the physical significance (reliability) of confidence intervals in the framework of both Frequentist and Bayesian statistical theories. We consider the expectation value of the upper limit in the absence of a signal (that we propose to call &#34;exclusion potential&#34;, instead of &#34;sensitiv

  68. Nickolay Y. Gnedin

    I use simulations of cosmological reionization to quantify the effect of photoionization on the gas fraction in low mass objects, in particular the characteristic mass scale below which the gas fraction is reduced compared to the universal value. I show that this characteristic scale can be up to an order of magnitude lower than the linear theory Jeans mass,

  69. S. James Gates,, Marcus T. Grisaru, Silvia Penati

    By use of a special homotopy operator, we present an explicit, closed-form and simple expression for the left-right Bardeen-Gross-Jackiw anomalies described as the proper superspace integral of a superfunction.

  70. E. Bagan, M. Lavelle, D. McMullan

    We calculate the screening and anti-screening contributions to the inter-quark potential in 2+1 dimensions, which is relevant to the high temperature limit of QCD. We demonstrate that the relative strength of screening to anti-screening agrees with the 3+1 dimensional theory to better than one percent accuracy.

  71. Shiro Kawabata

    The concept of quantum interleaver and a simple method of quantum burst-error correction is proposed. By using the quantum interleaver, any quantum burst-errors that have occurred spread over the interleaved code word, so that we can construct good quantum burst-error correcting codes without increasing the redundancy of the code. We also discuss the general

  72. J. Ambjorn, J. Jurkiewicz, R. Loll

    A well-defined regularized path integral for Lorentzian quantum gravity in three and four dimensions is constructed, given in terms of a sum over dynamically triangulated causal space-times. Each Lorentzian geometry and its associated action have a unique Wick rotation to the Euclidean sector. All space-time histories possess a distinguished notion of a disc

  73. I. Brevik, T. A. Yousef

    The finite temperature Casimir free energy is calculated for a dielectric ball of radius $a$ embedded in an infinite medium. The condition $εμ=1$ is assumed for the inside/outside regions. Both the Green function method and the mode summation method are considered, and found to be equivalent. For a dilute medium we find, assuming a simple &#34;square&#34; di

  74. Felix von Oppen, Bertrand I. Halperin, Ady Stern

    Recent experiments seem to confirm predictions that interactions lead to charge density wave ground states in higher Landau levels. These new ``correlated&#39;&#39; ground states of the quantum Hall system manifest themselves for example in a strongly anisotropic resistivity tensor. We give a brief introduction and overview of this new and emerging field.

  75. Rodrigo Ibata, Michael Irwin, Olivier Bienayme, Ralf Scholz

    We present the discovery and spectroscopic identification of two very high proper motion ancient white dwarf stars, found in a systematic proper motion survey. Their kinematics and apparent magnitude clearly indicate that they are halo members, while their optical spectra are almost identical to the recently identified cool Halo white dwarf WD0346+246. Canon

  76. Michael Dine

    There are at least two serious moduli problems in string cosmology. The first is the possibility that moduli dominate the energy density at the time of nucleosynthesis. The second is that they may not find their minima all together. After reviewing some previously proposed solutions to these problems, we propose another: all of the moduli but the dilaton sit

  77. Josiph Mladenov Rangelov

    The physical model (PhsMdl) of the relativistic quantized Dirac&#39;s electron (DrEl) is proposed. The DrEl is regarded as a point-like (PntLk) elementary electric charge (ElmElcChrg), taking simultaneously part in following four disconnected different motions: a/ in Einstein&#39;s random trembling harmonic shudders as a result of momentum recoils (impulse k

  78. B. Krippa

    The effective chiral theory of the in-medium NN interactions is considered. The shallow bound states, which complicate the effective field theory analysis in vacuum do not exist in matter. We show that the next-to-leading order terms in the chiral expansion of the effective Lagrangian can be interpreted as corrections so that the expansion is systematic. The

  79. Miloslav Znojil

    The fourth, missing example of an exactly solvable complex potential with PT symmetry V(x) = [V(-x)]^* defined on a bent contour and leading, at the real energies, to the Jacobi polynomial wave functions is found in a generalized Hulthen interaction.

  80. T. A. Larsson

    The Mickelsson-Faddeev (MF) algebra can naturally be embedded in a non-Lie algebra, which suggests that it has no Fock representations. The difficulties are due to the inhomogeneous term in the connection&#39;s transformation law. Omitting this term yields a ``classical MF algebra&#39;&#39;, which has other abelian extensions that do possess Fock modules. I

  81. V. Ancona, G. Ottaviani

    We study some properties of the natural action of $SL(V_0) \times...\times SL(V_p)$ on nondegenerate multidimensional complex matrices $A\in¶(V_0\otimes...\otimes V_p)$ of boundary format(in the sense of Gelfand, Kapranov and Zelevinsky); in particular we characterize the non stable ones,as the matrices which are in the orbit of a &#34;triangular&#34; matrix

  82. Kota Yoshioka

    In this paper, we show the moduli spaces of stable sheaves on K3 surfaces are irreducible symplectic manifolds, if the associated Mukai vectors are primitive. More precisely, we show that they are related to the Hilbert scheme of points. We also compute the period of these spaces. As an application of our result, we discuss Montonen-Olive duality in Physics.

  83. R. Ibáñez, Yu. Rudyak, A. Tralle, L. Ugarte

    In the present paper we study the variation of the dimensions $h_k$ of spaces of symplectically harmonic cohomology classes (in the sense of Brylinski) on closed symplectic manifolds. We give a description of such variation for all 6-dimensional nilmanifolds equipped with symplectic forms. In particular, it turns out that certain 6-dimensional nilmanifolds p

  84. A. Campillo, F. Delgado, S. M. Gusein-Zade

    We give two formulae which express the Alexander polynomial $Δ^C$ of several variables of a plane curve singularity $C$ in terms of the ring ${\cal O}_{C}$ of germs of analytic functions on the curve. One of them expresses $Δ^C$ in terms of dimensions of some factorspaces corresponding to a (multi-indexed) filtration on the ring ${\cal O}_{C}$. The other one

  85. Vladimir Belitsky, Pablo A. Ferrari, Mikhail V. Menshikov, Serguei Yu. Popov

    We consider a one-dimensional nearest-neighbor interacting particle system, which is a mixture of the simple exclusion process and the voter model. The state space is taken to be the countable set of the configurations that have a finite number of particles to the right of the origin and a finite number of empty sites to the left of it. We obtain criteria fo

  86. Radu Todor, Ionuţ Chiose, George Marinescu

    We study the existence of $L^2$ holomorphic sections of invariant line bundles over Galois coverings of Zariski open sets in Moishezon manilolds. We show that the von Neuman dimension of the space of $L^2$ holomorphic sections is bounded below under reasonable curvature conditions. We also give criteria for a a compact complex space with isolated singulariti

  87. Vladimir D. Lyakhovsky

    It is demonstrated how chains of twists for classical Lie algebras induce the new twist deformations (the deformed Yangians) that quantize the generalized rational solutions of the classical Yang-Baxter equation. For the case of Y(g) with g=so(2N+1) the explicit expression for the corresponding R-matrix is given in the defining representation.

  88. Yu. Nesterenko, M. Waldschmidt

    A sharp explicit estimate is proved for the difference $e^β-α$ when $α$ and $β$ are nonzero algebraic numbers.

  89. T. Gannon

    The fusion rings associated to affine Kac-Moody algebras appear in several different contexts in math and mathematical physics. In this paper we find all automorphisms of all affine fusion rings, or equivalently the symmetries of the corresponding fusion coefficients. Most of these are directly related to symmetries of the corresponding Coxeter-Dynkin diagra

  90. Andrea Loi, Riccardo Piergallini

    We prove that Stein surfaces with boundary coincide up to orientation preserving diffeomorphisms with simple branched coverings of $\B^4$ whose branch set is a positive braided surface. As a consequence, we have that a smooth oriented 3-manifold is Stein fillable iff it has a positive open-book decomposition.

  91. Morihiko Saito

    Let X be a complex surface with no nontrivial 2-forms. Then we show that Bloch&#39;s conjecture is true (i.e. the Albanese map in this case is injective) if and only if any homologically trivial idempotent in the ring of correspondences vanishes. Furthermore the cube of the ideal of homologically trivial correspondences is zero if these equivalent conditions

  92. Klaus Behrndt, Mirjam Cvetic

    Gauged supergravities (in four and five dimensions) with eight supercharges and with vector supermultiplets have a unique ultra-violet (UV) fixed point on a given physical domain \cal M of the space of the scalar fields. We show that in these models the infra-red (IR) fixed points are located on the boundary of \cal M, where the space-time metric becomes sin

  93. M. Cvetic, H. Lu, C. N. Pope

    We study singular, supersymmetric domain-wall solutions supported by the massive breathing mode scalars of, for example, sphere reductions in M-theory or string theory. The space-time on one side of such a wall is asymptotic to the Cauchy horizon of the anti-de Sitter (AdS) space-time. However, on the other side there is a naked singularity. The higher-dimen

  94. Paul H. Frampton

    Conformality is the idea that at TeV scales enrichment of the standard model particle spectrum leads to conformal invariance at a fixed point of the renormalization group. Some aspects of conformality in particle phenomenology and cosmology are discussed.

  95. Marco Laucelli Meana, Jesús Puente Peñalba

    We use the AdS/SYM correspondence to study the relevant effects of compactified dimensions on the D-brane dynamics. We present a detailed picture of the T-duality transition between branes in type IIA and type IIB supergravity. An analysis of the renormalization scheme coming from the expectation values of background fields and the role of Wilson lines in it

  96. N. Mankoc Borstnik, H. B. Nielsen, C. D. Froggatt

    Can one make a Majorana field theory for fermions starting from the zero mass Weyl theory, then adding a mass term as an interaction? The answer to this question is: yes we can. We can proceed similarly to the case of the Dirac massive field theory. In both cases one can start from the zero mass Weyl theory and then add a mass term as an interacting term of

  97. Chris Quigg

    I sketch some pressing questions in several active areas of particle physics and outline the challenges they present for the design and operation of detectors.

  98. Eric Laenen, George Sterman, Werner Vogelsang

    We exhibit a method for simultaneously treating recoil and threshold corrections in single-photon inclusive cross sections, working within the formalism of collinear factorization. This approach conserves both the energy and transverse momentum of resummed radiation. At moderate p_T, we find the potential for substantial enhancements from higher-order pertur

  99. R. J. Fries, A. Schäfer, E. Stein, B. Müller

    We calculate the Drell-Yan cross section, resolving the full kinematics of the lepton pair, at high transverse momentum for hadron nucleus collisions. We use the general framework of Luo, Qiu and Sterman to calculate double scattering contributions that are of twist-4 and demonstrate their nuclear enhancement. By comparing single and double scattering at RHI

  100. V. A. Khoze, A. D. Martin, M. G. Ryskin

    Double diffractive Higgs production at $pp$ (or $\bar{p}p$) colliders continues to attract attention as a potential signal in the search for the boson. We present improved perturbative QCD estimates of the event rates for both the exclusive and inclusive double diffractive Higgs processes, paying particular attention to the survival probability of the rapidi