Skip to content

April 2002 arXiv papers

Showing 1–100 of 2,793 papers

  1. Gerald V. Dunne, Christian Schubert

    We analyze the structure of the imaginary part of the two-loop Euler-Heisenberg QED effective Lagrangian for a constant self-dual background. The novel feature of the two-loop result, compared to one-loop, is that the prefactor of each exponential (instanton) term in the imaginary part has itself an asymptotic expansion. We also perform a high-precision test

  2. Gerald V. Dunne, Christian Schubert

    We show that, for both scalar and spinor QED, the two-loop Euler-Heisenberg effective Lagrangian for a constant Euclidean self-dual background has an extremely simple closed-form expression in terms of the digamma function. Moreover, the scalar and spinor QED effective Lagrangians are very similar to one another. These results are dramatic simplifications co

  3. M. I. Caicedo, I. Martin, A. Restuccia

    We describe a global approach to the study of duality transformations between antisymmetric fields with transitions and argue that the natural geometrical setting for the approach is that of gerbes, these objects are mathematical constructions generalizing U(1) bundles and are similarly classified by quantized charges. We address the duality maps in terms of

  4. Shuichi Murakami, Ryuichi Shindou, Naoto Nagaosa, Andrei S. Mishchenko

    We study the excitonic states in CaB6 in terms of the Ginzburg-Landau theory. By minimizing the free energy and by comparing with experimental results, we identify two possible ground states with exciton condensation. They both break time-reversal and inversion symmetries. This leads to various magnetic and optical properties. As for magnetic properties, it

  5. Subir Sarkar

    A satisfactory theory of quantum gravity will very likely require modification of our classical perception of space-time, perhaps by giving it a 'foamy' structure at scales of order the Planck length. This is expected to modify the propagation of photons and other relativistic particles such as neutrinos, such that they will experience a non-trivial

  6. Francis Halzen, Dan Hooper

    This is a review of neutrino astronomy anchored to the observational fact that Nature accelerates protons and photons to energies in excess of $10^{20}$ and $10^{13}$ eV, respectively. Although the discovery of cosmic rays dates back close to a century, we do not know how and where they are accelerated. Basic elementary-particle physics dictates a universal

  7. E. Korobkina, R. Golub, B. W. Wehring, A. R. Young

    Ultra-cold neutrons (UCN) are neutrons with energies so low they can be stored in material bottles and magnetic traps. They have been used to provide the currently most accurate experiments on the neutron life time and electric dipole moment. UCN can be produced in superfluid Helium at significantly higher densities than by other methods. The predominant pro

  8. Vyacheslav S. Rychkov

    We study path-integrals over reparametrizations of the world-sheet boundary. Such integrals arise when string propagates between fixed space-time contours. In gauge/string duality they are needed to describe gauge theory Wilson loops. We show that (1) in AdS/CFT, the integral is well defined and gives a finite 1-loop correction to the Wilson loop; (2) in cri

  9. J. Carlos Egues, Guido Burkard, Daniel Loss

    We study shot noise for spin-polarized currents and entangled electron pairs in a four-probe (beam splitter) geometry with a local Rashba spin-orbit (s-o) interaction in the incoming leads. Within the scattering formalism we find that shot noise exhibits Rashba-induced oscillations with continuous bunching and antibunching. We show that entangled states and

  10. Thibault Damour, Federico Piazza, Gabriele Veneziano

    In a recently proposed scenario, where the dilaton decouples while cosmologically attracted towards infinite bare string coupling, its residual interactions can be related to the amplitude of density fluctuations generated during inflation, and are large enough to be detectable through a modest improvement on present tests of free-fall universality. Provided

  11. Alex Krasnitz, Yasushi Nara, Raju Venugopalan

    We compute the elliptic flow generated by classical gluon fields in a high energy nuclear collision. The classical gluon fields are described by a typical momentum scale, the saturation scale Lambda_s, which is, for RHIC energies, of the order of 1-2 GeV. A significant elliptic flow is generated only over time scales on the order of the system size R. The fl

  12. L. Cornalba, M. S. Costa, C. Kounnas

    We propose a new cosmological scenario which resolves the conventional initial singularity problem. The space-time geometry has an unconventional time-like singularity on a lower dimensional hypersurface, with localized energy density. The natural interpretation of this singularity in string theory is that of negative tension branes, for example the orientif

  13. Itzhak Bars, Yutaka Matsuo

    Using the Moyal star product, we define open bosonic string field theory carefully, with a cutoff, for any number of string oscillators and any oscillator frequencies. Through detailed computations, such as Neumann coefficients for all string vertices, we show that the Moyal star product is all that is needed to give a precise definition of string field theo

  14. S. F. King

    Recent SNO results strongly favour the large mixing angle (LMA) MSW solar solution. We argue that there are only two technically natural low energy neutrino mass matrix structures consistent with the LMA MSW solution, corresponding to either a hierarchy or an inverted hierarchy with pseudo-Dirac neutrinos. We first present a model-independent analysis in whi

  15. Sadhan K. Adhikari

    Using the time-dependent mean-field Gross-Pitaevskii equation we study the dynamics of small repulsive Bose-Einstein condensed vortex states of ^{85}Rb atoms in a cylindrical trap with low angular momentum hbar L per atom (L <= 6), when the atomic interaction is suddenly turned attractive by manipulating the external magnetic field near a Feshbach resonance.

  16. R Horan, A Khvedelidze, M Lavelle, D McMullan

    A systematic approach to the description of gauge invariant charges is presented and applied to the construction of both the static colour charge configuration in QCD and the monopole solution in pure SU(2). The gauge invariant non-abelian monopole offers a new style of order parameter for monopole condensation.

  17. Masafumi Fukuma, So Matsuura

    We carry out field redefinitions in ten-dimensional Type IIB supergravity and show that they do not give rise to any physical corrections to the holographic renormalization group structure in the AdS/CFT correspondence. We in particular show that the holographic Weyl anomaly of the N=4 SU(N) super Yang-Mills theory does not change under the field redefinitio

  18. Oleg Lebedev, Maxim Pospelov

    Supersymmetric loop corrections induce potentially large CP-violating couplings of the Higgs bosons to nucleons and electrons that do not vanish in the limit of heavy superpartners. The Higgs-mediated CP-odd four-fermion operators are enhanced by tan^3 beta and induce electric dipole moments of heavy atoms which exceed the current experimental bounds for the

  19. Yusuke Kimura

    We study a noncommutative gauge theory on a fuzzy four-sphere. The idea is to use a matrix model with a fifth-rank Chern-Simons term and to expand matrices around the fuzzy four-sphere which corresponds to a classical solution of this model. We need extra degrees of freedom since algebra of coordinates does not close on the fuzzy four-sphere. In such a const

  20. V. Berezinsky, A. Z. Gazizov, S. I. Grigorieva

    We argue that an astrophysical solution to UHECR problem is viable. The pectral features of extragalactic protons interacting with CMB are calculated in model-independent way. Using the power-law generation spectrum $\propto E^{-γ_g}$ as the only assumption, we analyze four features of the proton spectrum: the GZK cutoff, dip, bump and the second dip. We fou

  21. C. Pujol, D. Davesne

    In this paper we consider dissipative hydrodynamic equations for systems with continuous broken symmetries. We first present the case of superfluidity, in which the symmetry U(1) is broken and then generalize to the chiral symmetry $SU(2)_L \times SU(2)_R$. The corresponding new transport coefficients are introduced.

  22. Harald W. Griesshammer

    A cartoon is drawn how and why to define and extract the energy dependence of the nucleon polarisabilities from low energy Compton scattering on the nucleon. The information dynamical polarisabilities contain about the low energy degrees of freedom inside the nucleon is extracted by comparing the chiral effective field theory calculation with dispersion theo

  23. Wolfgang Hollik, Elisabeth Kraus, Markus Roth, Christian Rupp

    The renormalization of the Minimal Supersymmetric Standard Model of electroweak interactions is presented to all orders of perturbation theory using the algebraic method. Special attention is directed to the issues of soft supersymmetry breaking, gauge fixing, and infrared finiteness. We discuss the implications of $\hbar$-dependent field parametrizations on

  24. Katrin Becker, Melanie Becker, Michael Haack, Jan Louis

    We obtain the vacuum solutions for M-theory compactified on eight-manifolds with non-vanishing four-form flux by analyzing the scalar potential appearing in the three-dimensional theory. Many of these vacua are not supersymmetric and yet have a vanishing three-dimensional cosmological constant. We show that in the context of Type IIB compactifications on Cal

  25. A. V. Savin, O. V. Gendelman

    The process of heat conduction in one-dimensional lattice with on-site potential is studied by means of numerical simulation. Using discrete Frenkel-Kontorova, $ϕ$--4 and sinh-Gordon we demonstrate that contrary to previously expressed opinions the sole anharmonicity of the on-site potential is insufficient to ensure the normal heat conductivity in these sys

  26. Patrick Huber, Manfred Lindner, Walter Winter

    We compare the physics potential of planned superbeams with the one of neutrino factories. Therefore, the experimental setups as well as the most relevant uncertainties and errors are considered on the same footing as much as possible. We use an improved analysis including the full parameter correlations, as well as statistical, systematical, and degeneracy

  27. D. Meloni

    In this talk I will consider the possibility of distinguish the usual three neutrino model from scenarios in which a light sterile neutrino is also present. I will show that the confusion with the so-called 3+1 scheme can arise in some particular region of the parameter space whereas it is essentially absent for the 2+2 scheme. Then I will discuss the ambigu

  28. Sebastian Goette, Nitu Kitchloo, Krishnan Shankar

    We compute the Eells-Kuiper invariant of the Berger manifold SO(5)/SO(3) and determine that it is diffeomorphic to the total space of an S^3-bundle over S^4. This answers a question raised by K. Grove and W. Ziller.

  29. Francisco Frutos-Alfaro

    Gravitational lenses are presently playing an important role in astrophysics. By means of these lenses the parameters of the deflector such as its mass, ellipticity, etc. and Hubble&#39;s constant can be determined. Using C, Xforms, Mesa and Imlib a computer program to visualize this lens effect has been developed. This program has been applied to generate s

  30. Motoi Endo, Motoaki Matsumura, Masahiro Yamaguchi

    The ansatz of vanishing A and B parameters eliminates CP violating complex phases in soft supersymmetry-breaking parameters of the minimal supersymmetric standard model, and thus provides a simple solution to the supersymmetry CP problem. Phenomenological implications of this ansatz are investigated in the framework of minimal supergravity. We show that elec

  31. D. Grumiller, W. Kummer, D. V. Vassilevich

    The study of general two dimensional models of gravity allows to tackle basic questions of quantum gravity, bypassing important technical complications which make the treatment in higher dimensions difficult. As the physically important examples of spherically symmetric Black Holes, together with string inspired models, belong to this class, valuable knowled

  32. Gi-Chol Cho

    We address the compatibility of a light sbottom (mass $2\sim 5.5 \gev$) and a light gluino (mass $12\sim 16 \gev$) with electroweak precision measurements. Such light particles have been suggested to explain the observed excess in the $b$ quark production cross section at the Tevatron. The electroweak observables may be affected by the sbottom and gluino thr

  33. Xin-zhou Li, Jian-gang Hao, Dao-jun Liu

    In light of the recent work by Sen and Gibbons, we present a phase-plane analysis on the cosmology containing a rolling tachyon field in a potential resulted from string theory. We show that there is no stable point on the phase-plane, which indicated that there is a coincidence problem if one consider tachyon as a candidate of quintessence. Furthermore, we

  34. Matthias Fuchs, Michael E. Cates

    A first principles approach to the nonlinear flow of dense suspensions is presented which captures shear thinning of colloidal fluids and dynamical yielding of colloidal glasses. The advection of density fluctuations plays a central role, suppressing the caging of particles and speeding up structural relaxation. A mode coupling approach is developed to explo

  35. S. Tsuruta, M. A. Teter, T. Takatsuka, T. Tatsumi

    With the successful launch of Chandra and XMM/Newton X-ray space missions combined with the lower-energy band observations, we are in the position where careful comparison of neutron star cooling theories with observations will make it possible to distinguish among various competing theories. For instance, the latest theoretical and observational development

  36. Hayaru Shouno, Koji Wada, Masato Okada

    We attempt image restoration in the framework of the Baysian inference. Recently, it has been shown that under a certain criterion the MAP (Maximum A Posterior) estimate, which corresponds to the minimization of energy, can be outperformed by the MPM (Maximizer of the Posterior Marginals) estimate, which is equivalent to a finite-temperature decoding method.

  37. Diego F. Torres

    The different definitions for the equation of state of a non-minimally coupled scalar field that have been introduced in the literature are analyzed. Particular emphasis is made upon those features that could yield to an observable way of distinguishing non-minimally coupled theories from General Relativity, with the same or with alternate potentials. It is

  38. M. Encinosa, B. Etemadi

    The eigenvalues and a series representation of the eigenfunctions of the Schrodinger equation for a particle on the surface of a torus are derived.

  39. Thomas Purdy, Martin Ligare

    We introduce a simple model for electromagnetically induced transparency in which all fields are treated quantum mechanically. We study a system of three separated atoms at fixed positions in a one-dimensional multimode optical cavity. The first atom serves as the source for a single spontaneously emitted photon; the photon scatters from a three-level Lambda

  40. XuBo Zou, K. Pahlke, W. Mathis

    We propose a novel scheme to implement a quantum controlled phase gate for trapped ions in thermal motion with one standing wave laser pulse. Instead of applying the rotating wave approximation this scheme makes use of the counter-rotating terms of operators. We also demonstrate that the same scheme can be used to generate maximally entangled states of $N$ t

  41. Peter Domokos, Thomas Salzburger, Helmut Ritsch

    Cavity-mediated cooling of the center--of--mass motion of a transversally, coherently pumped atom along the axis of a high--Q cavity is studied. The internal dynamics of the atomic dipole strongly coupled to the cavity field is treated by a non-perturbative quantum mechanical model, while the effect of the cavity on the external motion is described classical

  42. R. D. Gill, G. Weihs, A. Zeilinger, M. Zukowski

    A recent Letter by Hess and Philipp claims that Bell&#39;s theorem neglects the possibility of time-like dependence in local hidden variables, hence is not conclusive. Moreover the authors claim that they have constructed, in an earlier paper, a local realistic model of the EPR correlations. However, they themselves have neglected the experimenter&#39;s free

  43. Patrick Huang, Yongkyung Kwon, K. Birgitta Whaley

    We review the use of the path integral Monte Carlo (PIMC) methodology to the study of finite-size quantum clusters, with particular emphasis on recent applications to pure and impurity-doped He clusters. We describe the principles of PIMC, the use of the multilevel Metropolis method for sampling particle permutations, and the methods used to accurately incor

  44. L. V. Yakushevich, A. V. Savin, L. I. Manevitch

    Dynamics of topological solitons describing open states in the DNA double helix are studied in the frameworks of the model which takes into account asymmetry of the helix. It is shown that three types of topological solitons can occur in the DNA double chain. Interaction between the solitons, their interactions with the chain inhomogeneities and stability of

  45. Jorge G. Hirsch, Octavio Castanos, Peter O. Hess, Osvaldo Civitarese

    The 2 nu double beta decay half-lives of six nuclei, whose decays were previously reported as theoretically forbidden, are calculated by including the pairing interaction, which mixes different occupations and opens up the possibility of the decay. All allowed channels for the 0 nu double beta decay are also computed. The estimated 2 nu double beta half-live

  46. S. Schramm, D. Zschiesche

    We study the properties of rotating neutron stars within a generalized chiral SU(3)-flavor model. The influence of the rotation on the inner structure and the hyperon matter content of the star is discussed. We calculate the Kepler frequency and moments of inertia of the neutron star sequences. An estimate for the braking index of the associated pulsars is g

  47. R. Rodriguez-Guzman, J. L. Egido, L. M. Robledo

    The quadrupole deformation properties of the ground and low-lying excited states of the even-even Magnesium isotopes with N ranging from 8 to 28 have been studied in the framework of the angular momentum projected generator coordinate method with the Gogny force. It is shown that the N=8 neutron magic number is preserved (in a dynamical sense) in \nuc{20}{Mg

  48. S. Arole, D. S. Armstrong, T. P. Gorringe, M. D. Hasinoff

    We report measurements of $γ$--ray spectra from muon capture on $^{35}$Cl. For the allowed Gamow--Teller transitions to the $^{35}$S$(2939, 3/2^+)$ state and the $^{35}$S$(3421, 5/2^+)$ state we obtained their capture rates, hyperfine dependences and $γ$--$ν$ correlation coefficients. The capture rates and hyperfine dependences were compared to shell model c

  49. J. B. Natowitz, K. Hagel, Y. Ma, M. Murray

    From experimental observations of limiting temperatures in heavy ion collisions we derive Tc, the critical temperature of infinite nuclear matter. The critical temperature is 16.6 +- 0.86 MeV. Theoretical model correlations between Tc, the compressibility modulus, K the effective mass, $m^*$ and the saturation density, rho_s, are exploited to derive the quan

  50. Eduardo G. Vergini

    A generic chaotic eigenfunction has a non-universal contribution consisting of scars of short periodic orbits. This contribution, which can not be explained in terms of random universal waves, survives the semiclassical limit (when $\hbar$ goes to zero). In this limit, the sum of scarred intensities is a simple function of $η\equiv \sqrt{π/2} (f-1) h^{-1}_T

  51. T. Takenawa, M. Eguchi, B. Grammaticos, Y. Ohta

    We apply the algebraic-geometric techniques developed for the study of mappings which have the singularity confinement property to mappings which are integrable through linearisation. The main difference with respect to the previous studies is that the linearisable mappings have generically unconfined singularities. Despite this fact we are able to provide a

  52. Tai-Peng Tsai

    We consider a nonlinear Schrödinger equation with a bounded local potential in $R^3$. The linear Hamiltonian is assumed to have three or more bound states with the eigenvalues satisfying some resonance conditions. Suppose that the initial data is localized and small of order $n$ in $H^1$, and that its ground state component is larger than $n^{3-ε}$ with $ε>0

  53. D. J. Kaup, Boris A. Malomed

    We develop the technique of the variational approximation for solitons in two directions. First, one may have a physical model which does not admit the usual Lagrangian representation, as some terms can be discarded for various reasons. For instance, the second-harmonic-generation (SHG) model considered here, which includes the Kerr nonlinearity, lacks the u

  54. Avinash Khare, Uday Sukhatme

    Landen formulas, which connect Jacobi elliptic functions with different modulus parameters, were first obtained over two hundred years ago by making a suitable quadratic transformation of variables in elliptic integrals. We obtain and discuss significant generalizations of the celebrated Landen formulas. Our approach is based on some recently obtained period

  55. Franz Peherstorfer

    First a formula for the number of zeros of the orthogonal polynomial in the intervals is presented. Then a criteria about the appearance of a zero in a gap is given. Finally a necessary and sufficient condition is derived such that the zeros of the orthogonal polynomials have given accumulation points in the gaps. As a consequence it follows that every point

  56. Ilia Krasikov, Jeffrey C. Lagarias

    We study difference inequality systems for the 3x+1 problem introduced by the first author in 1989. These systemes can be used to give lower bounds for the number of integers below x that contain 1 in their forward orbit under the 3x+1 map. Previous methods gave away some information in these inequalities. We give an improvement which apparantly extracts ful

  57. A. A. Korenovskyy, A. K. Lerner, A. M. Stokolos

    We established an equivalence between the Gurov-Reshetnyak and Muckenhoupt A_\infty conditions for an arbitrary absolutely continuous measures.

  58. Z. K. Silagadze

    It is shown that multi-dimensional generalization of the vector product is only possible in seven dimensional space.

  59. Maximilian Kreuzer, Harald Skarke

    We describe our package PALP of C programs for calculations with lattice polytopes and applications to toric geometry, which is freely available on the internet. It contains routines for vertex and facet enumeration, computation of incidences and symmetries, as well as completion of the set of lattice points in the convex hull of a given set of points. In ad

  60. Raf Bocklandt

    In this paper we classify all the quivers and corresponding dimension vectors having a smooth space of semisimple representation classes. The result is that these quiver settings can be reduced via some specific reduction steps to 3 simple types.

  61. Rocco Chirivi&#39;, Andrea Maffei

    We study the ring of sections A(X) of a complete symmetric variety X, that is of the wonderful completion of G/H where G is an adjoint semi-simple group and H is the fixed subgroup for an involutorial automorphism of G. We find generators for Pic(X), we generalize the PRV conjecture to complete symmetric varieties and construct a standard monomial theory for

  62. Andrew Duncan, Robert H. Gilman

    The study of word hyperbolic groups is a prominent topic in geometric group theory; however word hyperbolic groups are defined by a geometric condition which does not extend naturally to semigroups. We propose a linguistic definition. Roughly speaking a semigroup is word hyperbolic if its multiplication table is a context free language. For groups this defin

  63. Kai Cieliebak

    It is shown that every subcritical Stein manifold is deformation equivalent to the product of a Stein manifold with $\C$.

  64. Pablo Alberca Bjerregaard, Candido Martin Gonzalez

    We present in this paper a routine which construct the ideal generated by a list of elements in a matrix Lie algebra at any particular characteristic. We have used this algorithm to analyze the problem of the simplicity of some Lie algebras.

  65. Isabel M. C. Salavessa

    We prove that under certain conditions on the mean curvature and on the Kaehler angles, a compact submanifold M of real dimension 2n, immersed into a Kaehler-Einstein manifold N of complex dimension 2n, must be either a complex or a Lagrangian submanifold of N, or have constant Kaehler angle, depending on n=1, n=2, or n \geq 3, and the sign of the scalar cur

  66. Julien Bichon

    We introduce the concept of Hopf-Galois system, a reformulation of the notion of Galois extension of the base field for a Hopf algebra. The main feature of our definition is a generalization of the antipode of an ordinary Hopf algebra. The main application of Hopf-Galois systems is the construction of monoidal equivalences between comodule categories over Ho

  67. Yael Karshon

    We count the conjugacy classes of maximal tori in the groups of symplectomorphisms of S^2 \times S^2 and of the blow-up of CP^2 at a point.

  68. Jens Lieberum

    We determine explicitly a rational even Drinfeld associator Q in a completion of the universal enveloping algebra of the Lie superalgebra gl(1|1)^3. More generally, we define a new algebra of trivalent diagrams that has a unique even horizontal group-like Drinfeld associator P. The associator P is mapped to Q by a weight system. As a result of independent in

  69. Craig D. Hodgson, Steven P. Kerckhoff

    This paper gives a quantitative version of Thurston&#39;s hyperbolic Dehn surgery theorem. Applications include the first universal bounds on the number of non-hyperbolic Dehn fillings on a cusped hyperbolic 3-manifold, and estimates on the changes in volume and core geodesic length during hyperbolic Dehn filling. The proofs involve the construction of a fam

  70. Tamas Hausel, Bernd Sturmfels

    Extending work of Bielawski-Dancer and Konno, we develop a theory of toric hyperkahler varieties, which involves toric geometry, matroid theory and convex polyhedra. The framework is a detailed study of semi-projective toric varieties, meaning GIT quotients of affine spaces by torus actions, and specifically, of Lawrence toric varieties, meaning GIT quotient

  71. R. Akbarpour, M. Khalkhali

    We extend our work in~\cite{rm01} to the case of Hopf comodule coalgebras. We introduce the cocylindrical module $C \natural^{} \mathcal{H}$, where $\mathcal{H}$ is a Hopf algebra with bijective antipode and $C$ is a Hopf comodule coalgebra over $\mathcal{H}$. We show that there exists an isomorphism between the cocyclic module of the crossed coproduct coalg

  72. Don N. Page

    The vacuum of a large-N gauge field on a p-torus has a spatial stress tensor with tension along the direction of smallest periodicity and equal pressures (but p times smaller in magnitude) along the other directions, assuming an AdS/CFT correspondence and a refined form of the Horowitz-Myers positive-energy conjecture. For infinite N, the vacuum exhibits a p

  73. Ashok Das, Silvana Perez

    We show that, at one loop, the magnetic mass vanishes at finite temperature in QED in any dimension. In QED$_{3}$, even the zero temperature part can be regularized to zero. We calculate the two loop contributions to the magnetic mass in QED$_{3}$ with a Chern-Simons term and show that it vanishes. We give a simple proof which shows that the magnetic mass va

  74. Ludwik Turko

    Internal microscopic symmetry of a many body system leads to global constraints. We obtain explicit forms of the global macroscopic condition assuring that at the microscopic level the evolution respects the overall symmetry.

  75. Carlos Castro

    Beginning with the most general fractal strings/sprays construction recently expounded in the book by Lapidus and Frankenhuysen, it is shown how the complexified extension of El Naschie&#39;s Cantorian-Fractal spacetime model belongs to a very special class of families of fractal strings/sprays whose scaling ratios are given by suitable pinary (pinary, $p$ p

  76. O. Oliveira, R. A. Coimbra

    Regular classical solutions of pure SU(3) gauge theories, in Minkowsky spacetime, are computed in the Landau gauge. The classical fields have an intrinsic energy scale and produce quark confinement if interpreted in the sense of a nonrelativistic potential. Moreover, the quark propagator in the background of these fields vanishes at large positive and negati

  77. Lorenz von Smekal, Philippe de Forcrand

    We study the fate of static fundamental charges in the thermodynamic limit from Monte-Carlo simulations of SU(2) with suitable boundary conditions.

  78. Jens Erler, Paul Langacker, Tianjun Li

    We consider the Z&#39;/Z mass hierarchy in a supersymmetric model in which the U(1)&#39; is broken in a secluded sector coupled to the ordinary sector only by gauge and possibly soft terms. A large mass hierarchy can be achieved while maintaining the normal sparticle spectra if there is a direction in which the tree level potential becomes flat when a partic

  79. A. D. Alhaidari

    The points raised in the Comment are addressed and except for one error, which will be corrected, the conclusion is that all of our findings are accurate.

  80. T. Asaka, W. Buchmüller, L. Covi

    The coset spaces E$_8$/SO(10)$\times$H$_F$ allow complex structures which can account for three quark-lepton generations including right-handed neutrinos. We show that in the context of supersymmetric SO(10) gauge theories in 6 dimensions they also provide the Higgs fields which are needed to break the electroweak and ${B-L}$ gauge symmetries, and to generat

  81. Winston Roberts

    We briefly discuss the predictions of the heavy quark effective theory for the semileptonic decays of a heavy pseudoscalar to a light one, or to a light vector meson. We point out that measurement of combinations of differential helicity decay rates at Cleo-c and the $B$ factories can provide a model independent means of extracting the ratio $|V_{ub}|/|V_{cd

  82. Aseshkrishna Datta, Abdelhak Djouadi, Margarete Muhlleitner

    We analyze the associated production at future high--energy $e^+e^-$ colliders, of first generation sleptons with neutralinos and charginos in the modes $e^+ e^-$ and $e γ$, in the framework of the Minimal Supersymmetric extension of the Standard Model. We show that the production rates, in particular for associated production of right--handed selectrons and

  83. F. Sannino, W. Schäfer

    We discuss the condensation of relativistic spin-one fields at high chemical potential. This phenomenon leads to the spontaneous breaking of rotational invariance, together with the breaking of internal symmetries.

  84. Zhenjun Xiao, Kuang-Ta Chao, Chong Sheng Li

    In this paper, we reexamine the new physics contributions to seven well measured $B \to PP$ decays in the standard model (SM) and the general two-Higgs-doublet model (model III) and compare the theoretical predictions with the new data. Within the considered parameter space we found that: (a) the measurements of the branching ratios for $B\to π^+ π^-, K^- π^

  85. Yong-Jun Zhang, Wei-Zhen Deng, Bo-Qiang Ma

    In this study, the proton is taken as an ensemble of quark-gluon Fock states. Using the principle of balance that every Fock state should be balanced with all of the nearby Fock states (denoted as the balance model), instead of the principle of detailed balance that any two nearby Fock states should be balanced with each other (denoted as the detailed balanc

  86. George Lazarides

    The early universe according to the big bang and the grand unified theories is discussed. The shortcomings of big bang are summarized together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay of the inflaton, and the resulting &#34;reheating&#34; of the universe are studied. The density perturbations produced b

  87. N. I. Kochelev

    It is shown that the specific space distribution of the nucleon axial charge may lead to the significant reduction of the cross section of the reaction $p+p\to D+e^++ν$ and may provide the mechanism to explain observed deficit of solar neutrinos.

  88. D. T. Son, M. A. Stephanov

    We point out that, in analogy with spin waves in antiferromagnets, all parameters describing the real-time propagation of soft pions at temperatures below the QCD chiral phase transition can be expressed in terms of static correlators. This allows, in principle, the determination of the soft pion dispersion relation on the lattice. Using scaling and universa

  89. V. Berezinsky, A. Z. Gazizov, S. I. Grigorieva

    The energy losses and spectra of Ultra High Energy Cosmic Rays (UHECR) are calculated for protons as primary particles. The attention is given to the energy losses due to electron-positron production in collisions with the microwave 2.73 K photons. The energy spectra are calculated for several models, which differ by production spectra and by source distribu

  90. Marko B. Popovic

    It is shown that the effective Standard Model theory with the physical Higgs mass lighter than $\sim 200$ GeV takes the form of an unbroken electroweak theory already at moderately high, $O(1 TeV)$, energy scales. No such transitional scale exists for the heavier Higgses. This result is independently obtained by two standard regularization methods.

  91. V. A. Belavin, M. N. Chernodub, M. I. Polikarpov

    We study numerically the monopole creation operator proposed recently by Frohlich and Marchetti. The operator is defined with the help of a three dimensional model which generates random Mandelstam strings. These strings imitate the Coulombic magnetic field around the monopole. We show that if the Mandelstam strings are condensed the creation operator discri

  92. Adriano Di Giacomo

    The evidence for dual superconductivity as a mechanism for color confinement is reviewed. New developments are presented for full QCD, i.e. in the presence of dynamical quarks.

  93. Achim W. Weidemann, Pisin Chen, Cho-Kuen Ng

    A &#39;plasma lens&#39; might be used to enhance the luminosity of future linear colliders. However, its utility for this purpose depends largely on the potential backgrounds that may be induced by the insertion of such a device in the interaction region of the detector. In this note we identify different sources of such backgrounds, calculate their event ra

  94. The DELPHI Collaboration, J. Abdallah

    Observation is made of rapidity-alignment of K+K- and ppbar pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The K+K- and ppbar data are consistent with predictions from the fragmentation string model. However, the ppbar data strongly disagree with the conventional implementatio

  95. Charles Francis

    Classically general covariance is found from the idea that a vector is a physical quantity which exists independently of choice of coordinate system and is unchanged by a change of coordinate system. It is often assumed that there exists some form of absolute mathematical space or space-time, and that in a flat space approximation vectors can be imagined bet

  96. Leor Barack, Amos Ori

    We derive the explicit values of all regularization parameters (RP) for a scalar particle in an arbitrary geodesic orbit around a Schwarzschild black hole. These RP are required within the previously introduced mode-sum method, for calculating the local self-force acting on the particle. In this method one first calculates the (finite) contribution to the se

  97. S. G. Ghosh, Naresh Dadhich

    We find the general solution of the Einstein equation for spherically symmetric collapse of Type II fluid (null strange quark fluid) in higher dimensions. It turns out that the nakedness and curvature strength of the shell focusing singularities carry over to higher dimensions. However, there is shrinkage of the initial data space for a naked singularity of

  98. Curt Cutler, Kip S. Thorne

    We review current best estimates of the strength and detectability of the gravitational waves from a variety of sources, for both ground-based and space-based detectors, and we describe the information carried by the waves.

  99. B. C. Paul

    In this paper, the cosmic no hair theorem for anisotropic Bianchi models which admit inflation with a scalar field is studied in the framework of Brane world. It is found that all Bianchi models except Bianchi type IX, transit to an inflationary regime with vanishing anisotropy. In the Brane world, anisotropic universe approaches the inflationary era much fa

  100. Hiromi Saida

    The Hawking radiation forms the essential basis of the black hole thermodynamics. The black hole thermodynamics denotes a nice correspondence between black hole kinematics and the laws of ordinary thermodynamics, but has been so far considered only in an asymptotically flat case. Does such the correspondence rely strongly on the feature of the gravity vanish