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August 2000 arXiv papers — page 17

Showing 1,601–1,700 of 2,591 papers

  1. Savely G. Karshenboim

    The Lamb shift measurement and theory are now both a dynamically developing field and we give a review of the current data. Critical comparison of theory and experiment can be done using a value of the proton charge radius and we pay attention to several results of its determination.

  2. Nils A. Tornqvist

    Based on previous papers I discuss how I understand the lightest scalars using a general coupled channel model. This model includes all light two-pseudoscalar thresholds, constraints from Adler zeroes, flavour symmetric couplings, unitarity and physically acceptable analyticity. One finds that with a large coupling there can appear two physical resonance pol

  3. E. Kh. Akhmedov

    We review the Floquet theory of linear differential equations with periodic coefficients and discuss its applications to neutrino oscillations in matter of periodically varying density. In particular, we consider parametric resonance in neutrino oscillations which can occur in such media, and discuss implications for oscillations of neutrinos traversing the

  4. Eung Jin Chun, Denis Comelli, David H. Lyth

    Flaton models of Peccei-Quinn symmetry have good particle physics motivation, and are likely to cause thermal inflation leading to a well-defined cosmology. They can solve the $μ$ problem, and generate viable neutrino masses. Canonical flaton models predict an axion decay constant F_a of order 10^{10} GeV and generic flaton models give F_a of order 10^9 GeV

  5. Aharon Levy

    The ep HERA collider started operation in summer of 1992. This talk summarizes some of the highlights of physics results obtained since then and discusses their impact on our understanding of Quantum Chromodynamics (QCD).

  6. V. Lengyel, V. Rubish, A. Shpenik, S. Chalupka

    The screened quasi-relativistic potential is used for describing spin-orbit splitting in $^{3}P_{J}$ waves of quark-antiquark system. Fermi-Breit equation is solved numerically in configuration interaction approximation. This approximation takes into account the mixing of wave functions up to fifth order and corrects substantially perturbation calculations.

  7. M. M. Muhlleitner

    This thesis presents a theoretical analysis of the properties of the Higgs bosons in the Standard Model (SM) and the minimal supersymmetric extension (MSSM), which can be investigated at the LHC and $e^+e^-$ linear colliders. The final goal is the reconstruction of the Higgs potential and thus the verification of the Higgs mechanism. MSSM Higgs boson product

  8. Daniel J. H. Chung, Edward W. Kolb, Antonio Riotto

    There is no known fundamental reason to demand as a cosmological initial condition that the bulk possess an SO(3,1) isometry. On the contrary, one expects bulk curvature terms that violate the SO(3,1) isometry at early epochs, leading to a violation of Lorentz invariance on our brane. Demanding that the Lorentz noninvariant terms are small leads to a new ``f

  9. Simeon Warner, Simon Catterall

    We report on simulations of DT simplicial gravity for manifolds with the topology of the 4-disk. We find evidence for four phases in a two-dimensional parameter space. In two of these the boundary plays no dynamical role and the geometries are equivalent to those observed earlier for the sphere $S^4$. In another phase the boundary is maximal and the quantum

  10. M. Pepe, Ph. de Forcrand

    We show how center vortices and Abelian monopoles both appear as local gauge ambiguities in the Laplacian Center gauge. Numerical results, for SU(2) and SU(3), support the view that the string tension obtained in the center-projected theory matches the full string tension when the continuum limit is taken.

  11. Ph. de Forcrand, M. Pepe

    I present a unified picture of center vortices and Abelian monopoles. Both appear as local gauge ambiguities in the Laplacian Center Gauge. This gauge is constructed for a general SU(N) theory. Numerical evidence is presented, for SU(2) and SU(3), that the projected $Z_N$ theory confines with a string tension similar to the non-Abelian one.

  12. L3 Collaboration

    We search for a Higgs particle with anomalous couplings in the e+e- -> H gamma, e+e- -> HZ and e+e- -> He+e- processes with the L3 detector at LEP. We explore the mass range 70GeV < m_H < 170GeV using 176pb^-1 of integrated luminosity at a center-of-mass energy of \sqrt{s} = 189GeV. The Higgs decays H -> bb, H -> gamma gamma and H -> Z gamma are considered i

  13. L3 Collaboration

    The process e+e- -> W+W-gamma is analysed using the data collected with the L3 detector at LEP at a centre-of-mass energy of 188.6GeV, corresponding to an integrated luminosity of 176.8pb^-1. Based on a sample of 42 selected W+W- candidates containing an isolated hard photon, the W+W-gamma cross section, defined within phase-space cuts, is measured to be: si

  14. D0 collaboration, B. Abbott

    Bottom quark production in pbar-p collisions at sqrt(s)=1.8 TeV is studied with 5 inverse picobarns of data collected in 1995 by the DO detector at the Fermilab Tevatron Collider. The differential production cross section for b jets in the central rapidity region (|y(b)| < 1) as a function of jet transverse energy is extracted from a muon-tagged jet sample.

  15. L3 Collaboration

    We investigate Bose-Einstein correlations (BEC) in W-pair production at root(s)=189GeV using the L3 detector at LEP. We observe BEC between particles from a single W decay in good agreement with those from a light-quark Z decay sample. We investigate their possible existence between particles coming from different W&#39;s. No evidence for such inter-W BEC is

  16. Ivan S. Booth

    I modify the quasilocal energy formalism of Brown and York into a purely Hamiltonian form. As part of the reformulation, I remove their restriction that the time evolution of the boundary of the spacetime be orthogonal to the leaves of the time foliation. Thus the new formulation allows an arbitrary evolution of the boundary which physically corresponds to a

  17. I. Radinschi

    We calculate the energy distribution in a static spherically symmetric nonsingular black hole space-time by using the Tolman&#39;s energy-momentum complex. All the calculations are performed in quasi-Cartesian coordinates. The energy distribution is positive everywhere and be equal to zero at origin. We get the same result as obtained by Y-Ching Yang by usin

  18. Su-Chan Park, Jeong-Man Park, Doochul Kim

    In a recent Letter, Bares and Mobilia proposed the method to find solutions of the stochastic evolution operator $H=H_0 + {γ\over L} H_1$ with a non-trivial quartic term $H_1$. They claim, ``Because of the conservation of probability, an analog of the Wick theorem applies and all multipoint correlation functions can be computed.&#39;&#39; Using the Wick theo

  19. Ning Ma, S. M. Girvin, R. Rajaraman

    The existence of attractions between like-charged colloids immersed in ionic solution have been discovered in recent experiments. This phenomenon contradicts the predictions of DLVO theory and indicates a failure of mean field theory. We study a toy model based on a two dimensional one-component plasma, which is exactly soluble at one particular coupling con

  20. Yu. Kagan, L. A. Maksimov

    We study the generation of excitations due to an &#39;&#39;impurity&#39;&#39;(static perturbation) placed into an oscillating Bose-condensed gas in the time-dependent trapping field. It is shown that there are two regions for the position of the local perturbation. In the first region the condensate flows around the &#39;&#39;impurity&#39;&#39; without gener

  21. S. M. Gatica, M. J. Bojan, G. Stan, M. W. Cole

    Grand canonical Monte Carlo simulations have been performed to determine the adsorption behavior of Ar and Kr atoms on the exterior surface of a rope (bundle) consisting of many carbon nanotubes. The computed adsorption isotherms reveal phase transitions associated with the successive creation of quasi-one dimensional lines of atoms near and parallel to the

  22. Robert Haslinger, Robert Joynt

    Photoemission experiments involve the motion of an electron near a conducting surface. This necessarily generates heat by ohmic losses from eddy currents. This inelastic scattering of the electrons will result in a downward shift in observed spectra. This effect is most pronounced in poorly conducting metals: in good metals the electron&#39;s field is screen

  23. L. Martin-Moreno, F. J. Garcia-Vidal, H. J. Lezec, K. M. Pellerin

    We present a fully three-dimensional theoretical study of the extraordinary transmission of light through subwavelength hole arrays in optically thick metal films. Good agreement is obtained with experimental data. An analytical minimal model is also developed, which conclusively shows that the enhancement of transmission is due to tunneling through surface

  24. M. L. Martins, G. Ceotto, S. G. Alves, C. C. B. Bufon

    A cellular automata model is proposed to analyze the progress of Citrus Variegated Chlorosis epidemics in São Paulo oranges plantation. In this model epidemiological and environmental features, such as motility of sharpshooter vectors which perform Lévy flights, hydric and nutritional level of plant stress and seasonal climatic effects, are included. The obs

  25. M. Enderle, H. M. Roennow, D. F. McMorrow, L. P. Regnault

    Here we report the first inelastic neutron scattering study of the magnetic excitations in the incommensurate phase of a spin-Peierls material. The results on CuGeO3 provide direct evidence of a finite excitation gap, two sharp magnetic excitation branches and a very low-lying excitation which is identified as a phason mode, the Goldstone mode of the incomme

  26. Trinh Xuan Hoang, Marek Cieplak

    We have studied folding mechanisms of three small globular proteins: crambin (CRN), chymotrypsin inhibitor 2 (CI2) and the fyn Src Homology 3 domain (SH3) which are modelled by a Go-like Hamiltonian with the Lennard-Jones interactions. It is shown that folding is dominated by a well-defined sequencing of events as determined by establishment of particular co

  27. B. Basu-Mallick, Anjan Kundu

    Recently a partially solvable many-body problem with nearest and next-nearest neighbour interactions is proposed [cond-mat/9904121]. We show that by adding a suitably chosen momentum dependent nearest neighbour interaction, such a model can be converted into an integrable system with Lax operator formulation and related conserved quantities. We also solve th

  28. B. A. Gurovich, D. I. Dolgy, E. A. Kuleshova, E. P. Velikhov

    Key circumstance of radical progress for technology of XXI century is the development of a technique which provides controllable producing three-dimensional patterns incorporating regions of nanometer sizes and required physical and chemical properties. Our paper for the first time proposes the method of purposeful direct transformation of the most important

  29. J. A. Duffy, S. M. Hayden, Y. Maeno, Z. Mao

    We report a study of the magnetization density in the mixed state of the unconventional superconductor S2RuO4. On entering the superconducting state we find no change in the magnitude or distribution of the induced moment for a magnetic field of 1 Tesla applied within the RuO2 planes. Our results are consistent with a spin-triplet Cooper pairing with spins l

  30. Gang He, Mark O. Robbins

    Simulations of the kinetic friction due to a layer of adsorbed molecules between two crystalline surfaces are presented. The adsorbed layer naturally produces friction that is consistent with Amontons&#39; laws and insensitive to parameters that are not controlled in experiments. The kinetic friction rises logarithmically with velocity as in many experimenta

  31. F. M. Izrailev, A. A. Krokhin, S. E. Ulloa

    It is shown that a non-periodic Kronig-Penney model exhibits mobility edges if the positions of the scatterers are correlated at long distances. An analytical expression for the energy-dependent localization length is derived for weak disorder in terms of the real-space correlators defining the structural disorder in these systems. We also present an algorit

  32. Michael B. Christiansen, Norman K. Glendenning

    We give a general thermodynamical argument showing that in neutron stars, the Coulomb structured mixed phase is always favored for any first order phase transition involving systems in equilibrium with baryon number and electric charge as the two independent components. This finding is likely to have important consequences for many neutron star properties, e

  33. T. Abu-Zayyad et. al

    The average extensive air shower longitudinal development profile as a function of shower age in the energy range from 10$^{17}$ to 10$^{18}$eV is measured using data from the hybrid HiRes/MIA experiment. An angular bin signal based Cerenkov light component subtraction method and a shower maximum fitting method using a local parabolic function are used to co

  34. Benjamin J. Weiner, J. A. Sellwood, T. B. Williams

    We report a dynamical determination of the separate contributions of disk and dark halo masses to the rotation curve of a spiral galaxy. We use fluid-dynamical models of gas flow in the barred galaxy NGC 4123 to constrain the dynamical properties of the galaxy: disk M/L, bar pattern speed, and the central density and scale radius of the dark halo. We derive

  35. Benjamin J. Weiner, T. B. Williams, J. H. van Gorkom, J. A. Sellwood

    The non-circular streaming motions in barred galaxies are sensitive to the mass of the bar and can be used to lift the degeneracy between disk and dark matter halo encountered when fitting axisymmetric rotation curves of disk galaxies. In this paper, we present photometric and kinematic observations of NGC 4123, a barred galaxy of modest size (V_rot = 130 km

  36. Erik Gullbring, Nuria Calvet, James Muzerolle, Lee Hartmann

    We compare accretion shock models with optical and ultraviolet spectra of pre-main sequence stars to (1) make the first determinations of accretion rates in intermediate mass T Tauri stars from continuum emission, and (2) derive improved estimates of accretion rates and extinctions for continuum T Tauri stars. Our method extends the shock models developed by

  37. S. L. Lumsden, P. J. Puxley, M. G. Hoare

    We have observed a large sample of compact planetary nebulae in the near-infrared to determine how the 2^1P-2^1S HeI line at 2.058um varies as a function of stellar effective temperature, Teff. The ratio of this line with HI Br g at 2.166um has often been used as a measure of the highest Teff present in a stellar cluster, and hence on whether there is a cut-

  38. R. G. Carlberg, H. K. C. Yee, S. L. Morris, H. Lin

    Galaxy groups likely to be virialized are identified within the CNOC2 intermediate redshift galaxy survey using an iterative method. The number-velocity dispersion relation is in agreement with the low-mass extrapolation of the cluster normalized Press-Schechter function. The two-point group-group correlation function has r_0=6.8+/- 0.3 Mpc, which is larger

  39. P. Boumis, C. Dickinson, J. Meaburn, C. D. Goudis

    A deep \ha image of interlocking filamentary arcs of nebulosity has been obtained with a wide-field ($\approx$ 30\degree diameter) narrow-band filter camera combined with a CCD as a detector. The resultant mosaic of images, extending to a galactic latitude of 65$^{o}$, has been corrected for field distortions and had galactic coordinates superimposed on it t

  40. S. B. Popov, M. E. Prokhorov, M. Colpi, A. Treves

    In this article we briefly review our recent results on evolution and properties of isolated neutron stars (INSs) in the Galaxy. As the first step we calculate a {\it census} of INSs in our Galaxy. We infer a lower bound for the mean kick velocity of NSs, $ <V> \sim $(200-300) ${\rm km s^{-1}}$. The same conclusion is reached for both a constant magnetic fie

  41. Phillip Helbig

    Kochanek (1992) suggested that the redshifts of gravitational lens galaxies rule out a large cosmological constant. This result was questioned by Helbig & Kayser (1996), who pointed out that selection effects related to the brightness of the lens can bias the results of this test against a high lambda value; however, we did not claim that the observations fa

  42. Phillip Helbig

    I give a brief overview of the current status of some aspects of the Cosmic Lens All-Sky Survey (CLASS): description of the survey, current list of lens systems, cosmological parameters from lensing statistics, H_0 from time delays, dark lenses, wide-separation lenses.

  43. G. Vasisht, E. V. Gotthelf, K. Torii, B. M. Gaensler

    We present follow-up observations of the serendipitously discovered 7-s X-ray pulsar AX J1845-0258, which displays characteristics similar to those observed in the anomalous X-ray pulsars (AXPs). We find a dramatic reduction in its 3-10 keV flux in both new ASCA and RXTE datasets. Within the pulsar&#39;s position-error locus, we detect a faint point source,

  44. Giovanni Fasano, Bianca M. Poggianti, Warrick J. Couch, Daniela Bettoni

    We have studied the evolution of galaxian morphologies from ground-based, good-seeing images of 9 clusters at z=0.09-0.25. The comparison of our data with those relative to higher redshift clusters (Dressler et al. 1997) allowed us to trace for the first time the evolution of the morphological mix at a look-back time of 2-4 Gyr, finding a dependence of the o

  45. S. F. Helsdon, T. J. Ponman

    We compare the X-ray properties of loose and compact galaxy groups, using a combined sample of 42 groups. We find that we are unable to separate loose and compact groups on the luminosity-temperature relation, the luminosity-velocity dispersion relation or the velocity dispersion-temperature relation using equally weighted errors. This suggests that the dist

  46. J. J. Bryant, R. W. Hunstead

    We present optical and near-infrared images and spectra of ESO248-G10, the host of giant radio galaxy MRC B0319-454. From near-infrared colours, the active nucleus is shown to be reddened by hot dust emission or dust extinction. Star forming regions are identified beyond a radius of 5&#34; (8.1 kpc) where hot gas is prevalent. The optical spectrum shows gas

  47. Soeren S. Larsen

    A search for young massive star clusters (YMCs) in the nearby face-on spiral galaxy M51 (NGC 5194) has been carried out using UBV CCD images from the prime focus camera on the Lick 3 meter Shane telescope. The YMC population is found to be quite rich with a specific U-band luminosity T_L(U) = 1.4, consistent with the high current star formation rate of this

  48. Xiao-Bing Wang, V. E. Kravtsov

    It is shown that the variance of the linear dc conductance fluctuations in an open quantum dot under a high-frequency ac pumping depends significantly on the spectral content of the ac field. For a sufficiently strong ac field $γτ_ϕ<< 1$, where $1/τ_ϕ$ is the dephasing rate induced by ac noise and $γ$ is the electron escape rate, the dc conductance fluctuati

  49. Ulf Lindstrom, Martin Rocek, Rikard von Unge

    We study solitons in three dimensional non-commutative scalar field theory at infinite non-commutativity parameter. We find the metric on the relative moduli space of all solitons of the form |n><n| and show that it is Kahler. We then find the geodesics of this metric and study the scattering of these solitons. In particular we find that the scattering is ge

  50. Savely G. Karshenboim

    We consider different options for the search for possible variations of the fundamental constants. We give a brief overview of the results obtained with several methods. We discuss their advantages and disadvantages with respect to simultaneous variations of all constants in both time and space in the range 10^{8}-10^{10} yr. We also suggest a few possibilit

  51. Antonina N. Fedorova, Michael G. Zeitlin

    We present some applications of general harmonic/wavelet analysis approach (generalized coherent states, wavelet packets) to numerical/analytical calculations in (nonlinear) quasiclassical/quantum beam dynamics problems. (Naive) deformation quantization, multiresolution representations and Wigner transform are the key points.

  52. Antonina N. Fedorova, Michael G. Zeitlin

    We present the applications of variational--wavelet approach for computing multiresolution/multiscale representation for solution of some approximations of Vlasov-Maxwell equations.

  53. Antonina N. Fedorova, Michael G. Zeitlin

    We present applications of variational -- wavelet approach to nonlinear (rational) rms envelope dynamics. We have the solution as a multiresolution (multiscales) expansion in the base of compactly supported wavelet basis.

  54. Antonina N. Fedorova, Michael G. Zeitlin

    We present the applications of variational--wavelet approach to nonlinear (rational) model for spin-orbital motion: orbital dynamics and Thomas-BMT equations for classical spin vector. We represent the solution of this dynamical system in framework of periodical wavelets via variational approach and multiresolution.

  55. Antonina N. Fedorova, Michael G. Zeitlin

    We present the applications of variational--wavelet approach for the analytical/numerical treatment of the effects of insertion devices on beam dynamics. We investigate the dynamical models which have polynomial nonlinearities and variable coefficients. We construct the corresponding wavelet representation for wigglers and undulator magnets.

  56. Antonina N. Fedorova, Michael G. Zeitlin

    We present the applications of variation -- wavelet analysis to polynomial/rational approximations for orbital motion in transverse plane for a single particle in a circular magnetic lattice in case when we take into account multipolar expansion up to an arbitrary finite number and additional kick terms. We reduce initial dynamical problem to the finite numb

  57. Y. Iwashita

    RFQ with a harmonic higher order quadrupole mode is studied. Assuming that we superpose a higher order mode with twice the frequency of the fundamental mode, a sawtooth waveform is approximated. In such a case, the bunching function is enhanced while the transverse stability is modified. Second order longitudinal harmonic component is also required to enable

  58. Antonina N. Fedorova, Michael G. Zeitlin

    We present applications of variational -- wavelet approach to different forms of nonlinear (rational) rms envelope equations. We have the representation for beam bunch oscillations as a multiresolution (multiscales) expansion in the base of compactly supported wavelet bases.

  59. Jacob Mostovoy, Theodore Stanford

    We define and study Vassiliev invariants for (long) Morse knots. It is shown that there are Vassiliev invariants which can distinguish some topologically equivalent Morse knots. In particular, there is an invariant of order 3 for Morse knots with one maximum that distinguishes two different representations of the figure eight knot. We also present the result

  60. E. Munoz-Garcia

    A metric vector space is asymptotically metrically normable (AMN) if there exists a norm asymptotically isometric to the distance. We prove that AMN vector spaces are rigid in the class of metric vector spaces under asymptotically isometric perturbations. This result follows from a general metric normability criterium. If the distance is translation invarian

  61. Andrei Okounkov

    We give a direct proof of the combinatorial formula for interpolation Macdonald polynomials by introducing certain polynomials, which we call generic Macdonald polynomials, which depend on $d$ additional parameters and specialize to all Macdonald polynomials of degree $d$. The form of these generic polynomials is that of a Bethe eigenfunction and they imitat

  62. Shun-Jen Cheng, Weiqiang Wang

    We study a dual pair of general linear Lie superalgebras in the sense of R. Howe. We give an explicit multiplicity-free decomposition of a symmetric and skew-symmetric algebra (in the super sense) under the action of the dual pair and present explicit formulas for the highest weight vectors in each isotypic subspace of the symmetric algebra. We give an expli

  63. A. Imaanpur

    In this note we examine the supermembrane action on Calabi-Yau 3-folds. We write down the Dirac-Born-Infeld part of the action, and show that it is invariant under the rigid spacetime supersymmetry.

  64. A. A. Tseytlin

    Following hep-th/0001204 we discuss the computation of quantum corrections near long IIB superstring configurations in AdS_5 x S^5 which are related to the Wilson loop expectation values in the strong coupling expansion of the dual n=4 SYM theory with large N. We use the Green-Schwarz description of superstrings in curved R-R backgrounds and demonstrate that

  65. Y. Stolov, M. Idel, S. Solomon

    We extend the Microscopic Representation approach to the quantitative study of religious and folk stories: A story encrypting symbolically the creation is deconstructed into its simplest conceptual elements and their relationships. We single out a particular kind of relationship which we call &#34;diagonal (or transitive) link&#34;: given 2 relations between

  66. B. K. Cho, Jae Hoon Kim, Young Jin Kim, Beom-hoan O

    Temperature-dependent magnetization (M(T)) and specific heat (C_p(T)) measurements were carried out on single crystal Sm_{1.85}Ce_{0.15}CuO_{4-delta} (T_c = 16.5 K). The magnetic anisotropy in the static susceptibility, chi {equiv} M/H, is apparent not only in its magnitude but also in its temperature dependence, with chi_{perp} for H{perp}c larger than chi_

  67. L. S. Schulman

    This is a reply to a comment of Casati, Chirikov and Zhirov (PRL 85, 896 (2000)) on PRL 83, 5419 (1999). The suitability of the particlar two-time boundary value problem used in the earlier PRL is argued.

  68. William G. Mathews, Fabrizio Brighenti

    We explore the possibly important influence of cooled interstellar gas on the fundamental plane of elliptical galaxies. Interstellar cooling is described by a parameterized sink term in the equation of continuity. Parameters that give the best fits to the X-ray observations of NGC 4472 are used as a template for the radial distribution of interstellar coolin

  69. Yu. V. Dumin

    Evading formation of the domain walls in cosmological phase transitions is one of key problems to be solved for explanation of the observed large-scale homogeneity of the Universe. The previous attempts to get around this obstacle led to imposing severe observational constraints on the parameters of the fields involved. Aim of the present report is to show t

  70. M. Salle, J. Smit, J. C. Vink

    The on-shell imaginary part of the retarded selfenergy of massive $\vr^4$ theory in 1+1 dimensions is logarithmically infrared divergent. This leads to a zero in the spectral function, separating its usual bump into two. The twin peaks interfere in time-dependent correlation functions, which causes oscillating modulations on top of exponential-like decay, wh

  71. Masako Bando, Tatsuo Kobayashi, Tatsuya Noguchi, Koichi Yoshioka

    In this paper we study renormalization-group evolutions of Yukawa matrices enhanced by Kaluza-Klein excited modes and analyze their infrared fixed-point structure. We derive necessary conditions to obtain hierarchies between generations on the fixed point. These conditions restrict how the fields in the models can extend to higher dimension. Several specific

  72. D. Edwards, H. Edwards, N. Holtkamp, S. Nagaitsev

    A technique for production of an electron beam with a high transverse emittance ratio. a &#34;flat&#34; beam, has been proposed by Brinkmann, Derbenev, and Floettmann.[1] The cathode of an RF-laser gun is immersed in a solenoidal magnetic field; as a result the beam emitted from a round laser spot has a net angular momentum. Subsequent passage through a quad

  73. G. Travish, S. Biedron, M. Borland, M. Hahne

    The use of existing linacs, and in particular light source injectors, for free-electron laser (FEL) experiments is becoming more common due to the desire to test FELs at ever shorter wavelengths. The high-brightness, high-current beams required by high-gain FELs impose technical specifications that most existing linacs were not designed to meet. Moreover, th

  74. S. N. Arteha

    Electric and magnetic self-fields can exist in the rotating plasma. A self-sustained rotation can be established in the plasma. The disturbed distribution function of rotating plasma is derived from the Vlasov equation. The propagation of waves in rotating plasma differs from that in the usual plasma. New terms for Landau damping appear. The local rotational

  75. Susumu Ariki

    In this short note, we describe the A_1^{(1)} soliton cellular automata as an evolution of a poset. This allows us to explain the conservation laws for the A_1^{(1)} soliton cellular automata, one given by Torii, Takahashi and Satsuma, and the other given by Fukuda, Okado and Yamada, in terms of the stack permutations of states in a very natural manner. As a

  76. Miguel S. Costa, Malcolm J. Perry

    We revisit the geometry representing l collinear Schwarzschild black holes. It is seen that the black holes&#39; horizons are deformed by their mutual gravitational attraction. The geometry has a string like conical singularity that connects the holes but has nevertheless a well defined action. Using standard gravitational thermodynamics techniques we determ

  77. P. M. Lavrov, P. Yu. Moshin

    We generalize the method of superfield Lagrangian BRST quantization in the part of the gauge-fixing procedure and obtain a quantization method that can be considered as an alternative to the Batalin - Vilkovisky formalism.

  78. Michael Melles

    The loop induced coupling of an intermediate mass Higgs boson to two photons is a sensitive and unique measure for precision tests of physics beyond the Standard Model. In this work we summarize recent results on the expected precision of the partial $Γ(H \to γγ)$ width at the $γγ$ option of a future linear collider. Heavy particles do not decouple in genera

  79. H. Leutwyler

    The effective field theory relevant for the analysis of QCD at low energies is reviewed. The foundations of the method are discussed in some detail and a few illustrative examples are described.

  80. H. Leutwyler

    In the first part of the talk, I discussed the nature of the effective theory that describes the properties of the pion-nucleon-interaction at low energies, using the static model as a starting point. In the second part, I then pointed out that the infrared singularities occurring in the pi-N scattering amplitude are stronger and of a more complex structure

  81. H. Athar

    Several cosmologically distant astrophysical sources may produce ultra-high energy cosmic neutrinos (E > 10^6 GeV) of all flavors above the atmospheric neutrino background. I study the effects of vacuum neutrino flavor mixing on this cosmic neutrino flux. Prospects for observations of these ultra-high energy cosmic neutrinos in large underwater/ice neutrino

  82. Stacy McGaugh

    The amplitudes of peaks in the angular power spectrum of anisotropies in the microwave background radiation depend on the mass content of the universe. The second peak should be prominent when cold dark matter is dominant, but is depressed when baryons dominate. Recent microwave background data are consistent with a purely baryonic universe with Omega(matter

  83. Max Tegmark, Matias Zaldarriaga, Andrew J. S. Hamilton

    We present a method for calculating large numbers of power spectra C_l and P(k) that accelerates CMBfast by a factor around 10^3 without appreciable loss of accuracy, then apply it to constrain 11 cosmological parameters from current Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) data. While the CMB alone still suffers from several degener

  84. Luis Anchordoqui, Kasper Olsen

    In this paper we consider some constraints on brane-world cosmologies. In the first part we analyze different behaviors for the expansion of our universe by imposing constraints on the speed of sound. In the second part, we study the nature of matter on the brane world by means of the well-known energy conditions. We find that the strong energy condition mus

  85. Eduardo C. Marino, Marcello B. Silva Neto

    We study the destruction of the antiferromagnetic order in the high-Tc superconductors La(2-x)Sr(x)CuO(4) and YBa(2)Cu(3)O(6+x) in the framework of the CP1-nonlinear sigma model formulation of the 2D quantum Heisenberg antiferromagnet. The dopants are introduced as independent fermions with appropriate dispersion relations determined by the shape of the Ferm

  86. Iouri Chepelev, Radu Roiban

    We present a rigorous proof of the convergence theorem for the Feynman graphs in arbitrary massive Euclidean quantum field theories on non-commutative R^d (NQFT). We give a detailed classification of divergent graphs in some massive NQFT and demonstrate the renormalizability of some of these theories.

  87. S. M. H. Wong, M. Belkacem, J. I. Kapusta, S. A. Bass

    We compute bremsstrahlung arising from the acceleration of individual charged baryons and mesons during the time evolution of high-energy Au+Au collisions at the Relativistic Heavy Ion Collider using a microscopic transport model. We elucidate the connection between bremsstrahlung and charge stopping by colliding artificial pure proton on pure neutron nuclei

  88. J. T. Lunardi, L. A. Manzoni, B. M. Pimentel, J. S. Valverde

    In this paper we consider the scalar sector of Duffin-Kemmer-Petiau theory in the framework of Epstein-Glaser causal method. We calculate the lowest order distributions for Compton scattering, vacuum polarization, self-energy and vertex corrections. By requiring gauge invariance of the theory we recover, in a natural way, the scalar propagator of the usual e

  89. P. M. Ferreira

    We calculate the one-loop contributions to the effective potential for the minimal supersymmetric model when scalar fields other than the Higgses have vacuum expectation values. The importance of these contributions for studies of charge and colour breaking bounds is discussed.

  90. J. Talbot, G. Tarjus, P. Viot

    An adsorption-desorption (or parking-lot) model can reproduce qualitatively the densification kinetics and other features of a weakly vibrated granular material. Here we study the the two-time correlation and response functions of the model and demonstrate that their behavior is consistent with recently observed memory effects in granular materials. Although

  91. Anne M Green, Karim A Malik

    During the preheating process at the end of inflation the amplification of field fluctuations can lead to the amplification of curvature perturbations. If the curvature perturbations on small scales are sufficiently large, primordial black holes (PBHs) will be overproduced. In this paper we study PBH production in the two-field preheating model with quadrati

  92. Dmitry N. Chigrin, Clivia M. Sotomayor Torres

    We review photonic band gap related properties of a simple periodic system of thin dielectric layers. Properties associated with forbidden and allowed bands of such one-dimensional photonic crystals are presented. A revision of forbidden bands properties leads to an omnidirectional Bragg mirror design. The anisotropy of allowed bands suggests the formation o

  93. R. Nebauer, J. Aichelin

    We discuss what the presently collected data tell us about the mechanism of multifragmentation by comparing the results of two different models, which assume or show an opposite reaction scenario, with the recent high statistics $4π$ experiments performed by the INDRA collaboration. We find that the statistical multifragmentation model and the dynamical Quan

  94. Robert Oeckl, Hendryk Pfeiffer

    We derive an exact duality transformation for pure non-Abelian gauge theory regularized on a lattice. The duality transformation can be applied to gauge theory with an arbitrary compact Lie group G as the gauge group and on Euclidean space-time lattices of dimension d >= 2. It maps the partition function as well as the expectation values of generalized non-A

  95. Dmitri Antonov

    In this talk, we discuss several topics related to the Abelian-projected SU(3)-QCD. First of them is the Aharonov-Bohm effect emerging during the extension of this theory by the introduction of the $Θ$-term. Another topic is devoted to various consequences of screening of the dual vector bosons by electric vortex loops. In particular, it is demonstrated that

  96. T. O. Eynck, S. Moch

    We present the threshold resummation for the cross section of heavy quark production in polarized deep-inelastic scattering to next-to-leading logarithmic accuracy and in single-particle inclusive kinematics. We expand our resummed result in alpha_s to next-to-leading and next-to-next-to-leading order and study the impact of these higher order corrections on

  97. Aristophanes Dimakis, Folkert Muller-Hoissen

    Using bicomplex formalism we construct generalizations of Fordy-Kulish systems of matrix nonlinear Schroedinger equations on two-dimensional space-time in two respects. Firstly, we obtain corresponding equations in three space-time dimensions. Secondly, a Moyal deformation is applied to the space-time coordinates and the ordinary product of functions replace

  98. K. S. Babu, T. Yanagida

    We point out that there is a serious cosmological problem in the supersymmetric standard model if a sterile neutrino is responsible for the solar neutrino oscillation, and propose a possible solution to this problem. We show that our solution induces naturally a mass of order 10^{-4} eV for the sterile neutrino, which is deeply related to the mechanism of su

  99. T. Renk, G. Piller, W. Weise

    A systematic multiple scattering formalism for vector meson electroproduction from nuclei is developed, with emphasis on the formation, propagation and hadronization scales for quark-gluon fluctuations of the virtual high-energy photon. The theory is compared to HERMES measurements of rho electroproduction on 14N. The nuclear transparency as a function of th

  100. Kimyeong Lee, David Tong, Sangheon Yi

    We employ the ADHM method to derive the moduli space of two instantons in U(1) gauge theory on a noncommutative space. We show by an explicit hyperKähler quotient construction that the relative metric of the moduli space of two instantons on $R^4$ is the Eguchi-Hanson metric and find a unique threshold bound state. For two instantons on $R^3\times S^1$, othe