March 1998 arXiv papers — page 16

S. Bethke, Z. Kunszt, D. E. Soper, W. J. Stirling

We correct an important misprint in the journal version of our earlier work on "New Jet Cluster Algorithms: Next-to-leading Order QCD...", published in Nucl. Phys. B 370 (1992) 310, which may have lead to an incorrect parametrisation of the leading order QCD coefficients for the JADE type jet cluster algorithms.

Felix M. Lev

The (electromagnetic or weak) current operator responsible for deep inelastic scattering (DIS) should be local and satisfy the well-known commutation relations with the representation operators of the Poincare group. The problem whether these conditions are compatible with the factorization theorem and operator product expansion is investigated in detail. We

M. Hashimoto, K. -I. Izawa, M. Yamaguchi, T. Yanagida

In supersymmetric theories, the Peccei-Quinn symmetry has a complex extension as a symmetry of the superpotential, so that the scalar potential always has an almost flat direction, the dilaton. We discuss how coherent oscillation of the dilaton affects axion cosmology. We stress that the dilaton decay, if its dominant mode is not into axions, releases large

Ning Wu

A supersymmetric model with U(1) gauge symmetry will be discussed in this paper. The model has strict U(1) gauge symmetry and supersymmetry simultaneously. Besides, there is a massive U(1) gauge field contained in the model.

K. Knecht, H. Verschelde

Starting from the parametric representation of a Feynman diagram, we obtain it's well defined value in dimensional regularisation by changing the integrals over parameters into contour integrals. That way we eventually arrive at a representation consisting of well-defined compact integrals. The result is a simple transformation of the integrand which giv

Kamiokande Collaboration, Y. Fukuda et al

From an exposure of 25.5~kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum $p_e > 100$ MeV/$c$, $p_μ> 200$ MeV/$c$, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio $(μ/e)_{DATA}/(μ/e)_{MC}$ was measured to

V. M. Khatsymovsky

We investigate whether self-maintained vacuum traversible wormhole can exist described by stationary but nonstatic metric. We consider metric being the sum of static spherically symmetric one and a small nondiagonal component which describes rotation sufficiently slow to be taken into account in the linear approximation. We study semiclassical Einstein equat

Janna Levin, Evan Scannapieco, Joseph Silk

Clues as to the geometry of the universe are encoded in the cosmic background radiation. Hot and cold spots in the primordial radiation may be randomly distributed in an infinite universe while in a universe with compact topology distinctive patterns can be generated. With improved vision, we could actually see if the universe is wrapped into a hexagonal pri

R. Estrada, S. A. Fulling

Asymptotic expansions of Green functions and spectral densities associated with partial differential operators are widely applied in quantum field theory and elsewhere. The mathematical properties of these expansions can be clarified and more precisely determined by means of tools from distribution theory and summability theory. (These are the same, insofar

M. B. Walker, P. Pairor

Surface bound states in a discrete-lattice model of a $d_{x^2 - y^2}$ cuprate superconductor are shown to be, in general, coherent superpositions of an incoming excitation and more than one outgoing excitation, and a simple graphical construction based on a surface Brillouin zone is developed to describe their nature. In addition, a momentum-dependent lifeti

A. R. Denton, H. Lowen

Freezing of charge-stabilized colloidal suspensions and relative stabilities of crystals and quasicrystals are studied using thermodynamic perturbation theory. Macroion interactions are modelled by effective pair potentials combining electrostatic repulsion with polymer-depletion or van der Waals attraction. Comparing free energies -- counterion terms includ

Igor Tsatskis

The possibility of disappearance of the diffuse-intensity peak splitting induced by the Fermi surface (i.e., of coalescence of the intensity maxima) with decreasing temperature is predicted. The underlying mechanism is the compensation of the reciprocal-space curvatures of the self-energy and the interaction. The theory also describes similar results obtaine

Václav Špička, Pavel Lipavský, Klaus Morawetz

For a system of non-interacting electrons scattered by neutral impurities, we derive a modified Boltzmann equation that includes quasiparticle and virial corrections. We start from quasiclassical transport equation for non-equilibrium Green's functions and apply limit of small scattering rates. Resulting transport equation for quasiparticles has gradient

Václav Špička, Pavel Lipavský, Klaus Morawetz

For a system of non-interacting electrons scattered by resonant levels of neutral impurities, we show that virial and quasiparticle corrections have nearly equal magnitudes. We propose a modification of the Boltzmann equation that includes quasiparticle and virial corrections and discuss their interplay on a dielectric function.

D. V. Ktitarev, V. B. Priezzhev

We present a detailed analysis of large scale simulations of avalanches in the 2D Abelian sandpile model. We compare statistical properties of two different decompositions of avalanches into clusters of topplings and waves of topplings. Auxiliary critical exponents are introduced and the existence of the exponent governing the contraction of avalanches claim

G. Fano, F. Ortolani, L. Ziosi

The density matrix renormalization group (DMRG) method introduced by White for the study of strongly interacting electron systems is reviewed; the method is variational and considers a system of localized electrons as the union of two adjacent fragments A, B. A density matrix rho is introduced, whose eigenvectors corresponding to the largest eigenvalues are

Keiji Ono, Hiroshi Shimada, Youiti Ootuka

The magneto-Coulomb oscillation, the single electron repopulation induced by external magnetic field, observed in a ferromagnetic single electron transistor is further examined in various ferromagnetic single electron devices. In case of double- and triple-junction devices made of Ni and Co electrodes, the single electron repopulation always occurs from Ni t

T V Ramakrishnan

The interaction between planar quasiparticles in a dx2-y2 superconductor and quantized vortices associated with a magnetic field perpendicular to the plane is shown to induce a pair potential with dxy symmetry, out a phase with dx2-y2 order. A microscopic calculation of a process involving quasiparticle scattering by the supercurrent around a vortex and Andr

S. A. Suslov, A. J. Roberts

Similarity solutions play an important role in many fields of science. The recent book of Barenblatt (1996) discusses many examples. Often, outstanding unresolved issues are whether a similarity solution is dynamically attractive, and if it is, to what particular solution does the system evolve. By recasting the dynamic problem in a form to which centre mani

Norman K. Glendenning

A phase transition in the nature of matter in the core of a neutron star, such as quark deconfinement or Bose condensation, can cause the spontaneous spin-up of a solitary millisecond pulsar. The spin-up epoch for our model lasts for $2\times 10^7$ years or 1/50 of the spin-down time (Glendenning, Pei and Weber in Ref. \cite{glen97:a}). The possibility exist

M. H. Pinsonneault, T. P. Walker, G. Steigman, V. K. Narayanan

The depletion of lithium during the pre-main sequence and main sequence phases of stellar evolution plays a crucial role in the comparison of the predictions of big bang nucleosynthesis with the abundances observed in halo stars. In the past a wide range of possible depletion factors, ranging from minimal in standard (non-rotating) stellar models to as much

R. Lieu, Y. Takahashi, T. W. B. Kibble

A theory is proposed to explain with simplicity the basic observed properties of a Gamma Ray Burst (GRB). It employs a well-known result of Schwinger, that static electric fields in excess of a critical value are unstable to pair creation, and catastrophically produces a thermal plasma at temperatures <= 0.5 MeV. By using observational values for the energy

Scott Burles, David Tytler

Observational constraints on the primordial deuterium-to-hydrogen ratio (D/H) can test theories of the early universe and provide constraints on models of big bang nucleosynthesis (BBN). We measure deuterium absorption in high-redshift, metal-poor QSO absorption systems and directly infer the value of primordial D/H. We present two measurements of D/H, and f

Norman K. Glendenning

A phase transition in the nature of matter in the core of a neutron star, such as quark deconfinement or Bose condensation, can cause the spontaneous spin-up of a solitary millisecond pulsar. The spin-up epoch for our model lasts for $2\times 10^7$ years or 1/50 of the spin-down time.

M. S. Oey, C. J. Clarke

We use the standard, adiabatic shell evolution to predict the size distribution N(R) for populations of SN-driven superbubbles in a uniform ISM. We derive N(R) for simple cases of superbubble creation rate and mechanical luminosity function. We then compare our predictions for N(R) with the largely complete HI hole catalogue for the SMC, with a view toward t

Ulf Torkelsson

I show in this paper that two types of magnetic torques can appear in the interaction between an accretion disc and a magnetic accretor. There is the well-known torque resulting from the difference in angular velocity between the accretion disc and the star, but in addition there is a torque coming from the interaction between the stellar magnetic field and

Norman K. Glendenning

A solitary millisecond pulsar, if near the mass limit, and undergoing a phase transition, either first or second order, provided the transition is to a substantially more compressible phase, will emit a blatantly obvious signal---spontaneous spin-up. Normally a pulsar spins down by angular momentum loss to radiation. The signal is trivial to detect and is es

B. L. Frye, T. J. Broadhurst, H. Spinrad, A. Bunker

We present new Keck observations of giant arcs in the cluster Abell 2390. High resolution two-dimensional spectra of two arcs show metal lines at z=4.040 +/- 0.005 with Lyman-alpha emission spatially separated from the stellar continuum. In addition, spectroscopy along the notorious `straight&#39; arc reveals two unrelated galaxies, at z=0.913 and z=1.033, w

David K. Strickland, Ian R. Stevens

Wind-blown bubbles, from those around massive O and Wolf-Rayet stars, to superbubbles around OB associations and galactic winds in starburst galaxies, have a dominant role in determining the structure of the Interstellar Medium. X-ray observations of these bubbles are particularly important as most of their volume is taken up with hot gas, 1E5 < T (K) < 1E8.

V. N. Lukash, E. V. Mikheeva

We argue that gravitational wave contribution to the cosmic microwave background anisotropy at angular scale $\sim 10^0$ may exceed 50% for some models of hybrid inflation producing standard cosmology with the density perturbation slope $n \simeq 1$.

Juan A. Miralles, Vadim Urpin, Denis Konenkov

We consider Joule heating caused by dissipation of the magnetic field in the neutron star crust. This mechanism may be efficient in maintaining a relatively high surface temperature in very old neutron stars. Calculations of the thermal evolution show that, at the late evolutionary stage ($t \geq 10$ Myr), the luminosity of the neutron star is approximately

John Feldmeier, Robin Ciardullo, George Jacoby

We report the initial results of a survey for intracluster planetary nebulae in the Virgo Cluster. In two 16&#39; x 16&#39; fields, we identify 69 and 16 intracluster planetary nebula candidates, respectively. In a third 16&#39; x 16&#39; field near the central elliptical galaxy M87, we detect 75 planetary nebula candidates, of which a substantial fraction a

M. R. S. Hawkins

It has been argued in a number of recent papers that dark matter is in the form of Jupiter mass primordial black holes which betray their presence by microlensing quasars. This lensing accounts for a number of characteristic properties of quasar light curves, in both single quasars and gravitationally lensed multiple systems, which are not explained on the b

Robert C. Duncan

There is evidence that soft gamma repeaters (SGRs) are neutron stars which experience frequent starquakes, possibly driven by an evolving, ultra-strong magnetic field. The empirical power-law distribution of SGR burst energies, analogous to the Gutenberg-Richter law for earthquakes, exhibits a turn-over at high energies consistent with a global limit on the

Vicent Quilis, Jose Ma. Ibanez, Diego Saez

Numerical simulations of galaxy clusters including two species -- baryonic gas and dark matter particles --are presented. Cold Dark Matter spectrum, Gaussian statistics and flat universe are assumed. The dark matter component is evolved numerically by means of a standard particle mesh method. The evolution of the baryonic component has been studied numerical

Rebecca Danos, Ue-Li Pen

We apply a unique gas fraction estimator to published X-ray cluster properties and we compare the derived gas fractions of observed clusters to simulated ones. The observations are consistent with a universal gas fraction of 0.15+/-0.01h_{50}^{-3/2} for the low redshift clusters that meet our selection criteria. The fair sampling hypothesis states that all c

T. Yaqoob

The method of obtaining confidence intervals on a subset of the total number of parameters (p) of a model used for fitting X-ray spectra is to perturb the best-fitting model until, for each parameter, a range is found for which the change in the fit statistic is equal to some critical value. This critical value corresponds to the desired confidence level and

D. Raboud, J. -C. Mermilliod

On the basis of the best available member list and duplicity information, we have studied the radial structure of Praesepe and of the very young open cluster NGC 6231. We have found mass segregation among the cluster members and between binaries and single stars, which is explained by the greater average mass of the multiple systems. However, the degree of m

Sergei Maslov, Paolo De Los Rios, Matteo Marsili, Yi-Cheng Zhang

We analyze the behavior of spatially anisotropic Bak-Sneppen model. We demonstrate that a nontrivial relation between critical exponents tau and mu=d/D, recently derived for the isotropic Bak-Sneppen model, holds for its anisotropic version as well. For one-dimensional anisotropic Bak-Sneppen model we derive a novel exact equation for the distribution of ava

Shiraz Minwalla

1 identify a correspondence between the various spherical harmonic modes of massless 11 dimensional fields propagating on the $AdS_{4/7}$ in an $AdS_{4/7} \times S^{7\4}$ compactification of M theory, and the corresponding operators, primary under the conformal group, on the world volume of $M_2,M_5$ branes. This is achieved by matching representations of th

Yu. B. Khavin, M. E. Gershenson, A. L. Bogdanov

The temperature and magnetic-field dependences of the resistance of one-dimensional (1D) conductors have been studied in the vicinity of the Thouless crossover. We find that on the weak localization (WL) side of the crossover, these dependences are consistent with the theory of quantum corrections to the resistance, and the phase breaking is due to the quasi

Ofer Aharony, Yaron Oz, Zheng Yin

We study the large N limit of the interacting superconformal field theories associated with N M5 branes or M2 branes using the recently proposed relation between these theories and M theory on AdS spaces. We first analyze the spectrum of chiral operators of the 6d (0,2) theory associated with M5 branes in flat space, and find full agreement with earlier resu

D. V. Averin

Amplitude of the Coulomb blockade oscillations is calculated for a single-mode Josephson junction with arbitrary electron transparency $D$. It is shown that the Coulomb blockade is suppressed in ballistic junctions with $D\to 1$. The suppression is described quantitatively as the Landau-Zener transition in imaginary time.

L. Randall, R. Rattazzi, E. Shuryak

The phase structure of SUSY gauge theories can be very different from their nonsupersymmetric counterparts. Nonetheless, there is interesting information which might be gleaned from detailed investigation of these theories. In particular, we study the precise meaning of the strong interaction scale $Λ$. We ask whether one can meaningfully apply naive dimensi

Michael Spira, Peter M. Zerwas

An introduction to electroweak symmetry breaking and Higgs physics is presented for the Standard Model and its supersymmetric extensions. A brief overview will also be given on strong interactions of the electroweak gauge bosons in alternative scenarios. In addition to the theoretical basis, the present experimental status of Higgs physics and implications f

Andy Gopie, Michael C. Ogilvie

Using lattice simulations of quenched QCD we estimate the finite size effects present when a gluon plasma equilibrates in a slab geometry, i.e., finite width but large transverse dimensions. Significant differences are observed in the free energy density for the slab when compared with bulk behavior. A small shift in the critical temperature is also seen. Th

Daniel C. Cabra, Enrique F. Moreno, Gerardo L. Rossini

We study the gauge invariant fermions in the fermion coset representation of $SU(N)_k$ Wess-Zumino-Witten models which create, by construction, the physical excitations (quasiparticles) of the theory. We show that they provide an explicit holomorphic factorization of $SU(N)_k$ Wess-Zumino-Witten primaries and satisfy non-Abelian braiding relations.

E. Kh. Akhmedov, V. A. Rubakov, A. Yu. Smirnov

We propose a new mechanism of leptogenesis in which the asymmetries in lepton numbers are produced through the CP-violating oscillations of ``sterile&#39;&#39; (electroweak singlet) neutrinos. The asymmetry is communicated from singlet neutrinos to ordinary leptons through their Yukawa couplings. The lepton asymmetry is then reprocessed into baryon asymmetry

C. J. Benesh, J. T. Londergan

Recent calculations of charge symmetry violation(CSV) in the valence quark distributions of the nucleon have revealed that the dominant symmetry breaking contribution comes from the mass associated with the spectator quark system.Assuming that the change in the spectator mass can be treated perturbatively, we derive a model independent expression for the shi

H. Kleinert, A. Chervyakov

Quadratic fluctuations require an evaluation of ratios of functional determinants of second-order differential operators. We relate these ratios to the Green functions of the operators for Dirichlet, periodic and antiperiodic boundary conditions on a line segment. This permits us to take advantage of Wronski&#39;s construction method for Green functions with

Renato Portugal

The problem of simplifying tensor expressions is addressed in two parts. The first part presents an algorithm designed to put tensor expressions into a canonical form, taking into account the symmetries with respect to index permutations and the renaming of dummy indices. The tensor indices are split into classes and a natural place for them is defined. The

J. M. Campbell, E. W. N. Glover, C. J. Maxwell

We directly fit the experimentally measured energy dependence of the average value of 1-Thrust, <1-T>, over the e^+e^- centre-of-mass energy range Q=14 - 172 GeV to the QCD expectation obtained by integrating up the evolution equation for d<1-T>/dlog Q in terms of <1-T>. We fit for Lambda_QCD, uncalculated O(alpha_S^3) and higher perturbative corrections par

Amand Faessler, Sergey Kovalenko, Fedor Simkovic

We examine the pion realization of the short ranged supersymmetric (SUSY) mechanism of neutrinoless double beta decay. It originates from the R-parity violating quark-lepton interactions of the SUSY extensions of the standard model of the electroweak interactions. We argue that pions are dominant SUSY mediators in neutrinoless double beta decay. The correspo

M. Cristina Diamantini, Carlo A. Trugenberger

Confining strings in 4D are effective, thick strings describing the confinement phase of compact U(1) and, possibly, also non-Abelian gauge fields. We show that these strings are dual to the gauge fields, inasmuch as their perturbative regime corresponds to the strong coupling (large e) regime of the gauge theory. In this regime they describe smooth surfaces

C. D. Fosco, F. A. Schaposnik

We find a representation for the determinant of a Dirac operator in an even number $D= 2 n$ of Euclidean dimensions as an overlap between two different vacua, each one corresponding to a bosonic theory with a quadratic action in $2 n + 1$ dimensions, with identical kinetic terms, but differing in their mass terms. This resembles the overlap representation of

Teruhiko Kawano, Kazumi Okuyama

We consider the compactification of Matrix theory on tori with background antisymmetric tensor field. Douglas and Hull have recently discussed how noncommutative geometry appears on the tori. In this paper, we demonstrate the concrete construction of this compactification of Matrix theory in a similar way to that previously given by Taylor.

S. G. Cooper, V. I. Kukulin, R. S. Mackintosh, E. V. Kuznetsova

We demonstrate a new approach to the analysis of extensive multi-energy data. For the case of d + He-4, we produce a phase shift analysis covering for the energy range 3 to 11 MeV. The key idea is the use of iterative perturbative data-to-potential inversion which can produce potentials which reproduce the data simultaneously over a range of energies. It thu

N. Banerjee, S. Sen

This paper consolidates noscalar hair theorem for a charged spherically symmetric black hole in four dimension in general relativity as well as in all scalar tensor theories, both minimally and nonminimally coupled, when the effective Newtonian constant of gravity is positive. However, there is an exception when the matter field itself is coupled to the scal

M. L. Falk

Molecular-dynamics simulations of fracture in metallic glass-like systems are observed to undergo embrittlement due to a small change in interatomic potential. This change in fracture toughness, however, is not accompanied by a corresponding change in flow stress. Theories of brittle fracture proposed by Freund and Hutchinson indicate that strain rate sensit

Giacomo M. D&#39;Ariano, Matteo G. A. Paris, Massimiliano F. Sacchi

An interaction scheme involving nonlinear $χ^{(2)}$ media is suggested for the generation of phase-coherent states (PCS). The setup is based on parametric amplification of vacuum followed by up-conversion of the resulting twin-beam. The involved nonlinear interactions are studied by the exact numerical diagonalization. An experimentally achievable working re

K. C. Ho, P. T. Leung, Alec Maassen van den Brink, K. Young

The second-quantization of a scalar field in an open cavity is formulated, from first principles, in terms of the quasinormal modes (QNMs), which are the eigensolutions of the evolution equation that decay exponentially in time as energy leaks to the outside. This formulation provides a description involving the cavity degrees of freedom only, with the outsi

A. Angelow

An explicit solution of the equation for the classical harmonic oscillator with smooth switching of the frequency has been found . A detailed analysis of a quantum harmonic oscillator with such frequency has been done on the base of the method of linear invariants. It has been shown that such oscillator possesses cofluctuant states, different from widely stu

Michael D. Westmoreland, Benjamin Schumacher

This paper shows that ordinary quantum mechanics is not consistent with the superluminal transmission of classical information.

Lov K. Grover

A framework is presented for the design and analysis of quantum mechanical algorithms, the sqrt(N) step quantum search algorithm is an immediate consequence of this framework. It leads to several other search-type applications - several examples are presented. Also, it leads to quantum mechanical algorithms for problems not immediately connected with search

Jonathan Engel, Karlheinz Langanke, Petr Vogel

A simple model based on the group SO(5) suggests that both the like-particle and neutron-proton components of isovector pairing correlations in odd-A nuclei are Pauli blocked. The same effect emerges from Monte Carlo Shell-model calculations of proton-rich nuclei in the full fp shell. There are small differences between the two models in their representation

R S Mackintosh, S G Cooper

It is now straightforward to carry out S-matrix to potential inversion over a very wide range of energies and for a wide range of projectile-target combinations. Inversion is possible in many cases involving spin. IP inversion also permits direct scattering data-to-potential inversion and furnishes powerful tools for the phenomenological analysis of nuclear

Qiang Zhao, Zhenping Li, C. Bennhold

An unified approach for vector meson photoproduction is presented in the constit quark model. The s- and u-channel resonance contributions are generated using an effective quark vector-meson Lagrangian. In addition, taking into account $π^0$ and $σ$ t-channel exchanges for diffractive production, the available total and differential cross section data for $ω

J. E. Amaro, A. M. Lallena, G. Co&#39;, A. Fabrocini

The validity of a model treating the short-range correlations up to the first order is studied by calculating the charge response of an infinite system and comparing the obtained results with those of a Fermi Hypernetted Chain calculation.

W. Oelert

Associated strangeness production close to threshold is a particularly clean example of how energy is converted into hadronic matter. Final results from the completed experiments of the PS185 collaboration at LEAR/CERN, using the antiproton-proton interaction to produce antihyperon-hyperon pairs, demonstrate that such studies form a powerful tool. First resu

Mark P. Owen

The Hardy-Rellich inequality given here generalizes a Hardy inequality of Davies (1984), from the case of the Dirichlet Laplacian of a region $Ω\subseteq\real^N$ to that of the higher order polyharmonic operators with Dirichlet boundary conditions. The inequality yields some immediate spectral information for the polyharmonic operators and also bounds on the

Mark P. Owen

We find a Gaussian off-diagonal heat kernel estimate for uniformly elliptic operators with measurable coefficients acting on regions $Ω\subseteq\real^N$, where the order $2m$ of the operator satisfies $N<2m$. The estimate is expressed using certain Riemannian-type metrics, and a geometrical result is established allowing conversion of the estimate into terms

Christian Pauly, Emma Previato

We study several subseries of the space of second order theta functions on the Jacobian of a non-hyperelliptic curve. In particular, we are interested in the subseries PΓ_{00} consisting of 2theta-divisors having multiplicity at least 4 at the origin, or, equivalently, containing the surface C-C, and in its analogues consisting of 2theta-divisors having high

Richard G. E. Pinch

We list the elliptic curves defined over $Q(\sqrt 5)$ with good reduction away from 2. There are 368 isomorphism classes. We give a global minimal model for each class.

Mark P. Owen

We find an asymptotic expression for the first eigenvalue of the biharmonic operator on a long thin rectangle. This is done by finding lower and upper bounds which become increasingly accurate with increasing length. The lower bound is found by algebraic manipulation of the operator, and the upper bound is found by minimising the quadratic form for the opera

Jaroslaw A. Wisniewski

In the present paper Mori extremal rays of a smooth projective manifold X are divided into two classes: L-supported and L-negligible (where ``L&#39;&#39; stands for ``Lefschetz&#39;&#39; since the division comes from Hard Lefschetz Theorem). Roughly speaking: L-supported rays are strongly distinguishable in topology while L-negligible rays have very mild geo

Victor Ginzburg

These lectures given in Montreal in Summer 1997 are mainly based on, and form a condensed survey of, the book by N. Chriss and V. Ginzburg: `Representation Theory and Complex Geometry&#39;, Birkhauser 1997. Various algebras arising naturally in Representation Theory such as the group algebra of a Weyl group, the universal enveloping algebra of a complex semi

A. O. Barvinsky, A. Yu. Kamenshchik

We obtain effective equations of inflationary dynamics for the mean inflaton and metric fields in the no-boundary and tunneling quantum states of the Universe. In the slow roll approximation (taking the form of the local Schwiger-DeWitt expansion) effective equations follow from the Euclidean effective action on the DeSitter gravitational instanton. Effectiv

Shamit Kachru, Yaron Oz, Zheng Yin

Novel 3+1 dimensional N=2 superconformal field theories (with tensionless BPS string solitons) are believed to arise when two sets of M5 branes intersect over a 3+1 dimensional hyperplane. We derive a DLCQ description of these theories as supersymmetric quantum mechanics on the Higgs branch of suitable 4d N=1 supersymmetric gauge theories. Our formulation al

S. Deser, G. W. Gibbons

We present some obvious physical requirements on gravitational avatars of non-linear electrodynamics and illustrate them with explicit determinantal Born-Infeld-Einstein models. A related procedure, using compensating Weyl scalars, permits us to formulate conformally invariant versions of these systems as well.

David Berenstein, Richard Corrado

We study the properties of wrapped membranes in matrix theory on ALE spaces. We show that the only BPS bound states of wrapped membranes that can form are roots of the $A$-$D$-$E$ group. We determine a bound on the energy of a bound state and find the correct dependence on the blow-up parameters and longitudinal momentum expected from M-Theory. For the $A_{n

Wellington da Cruz

We obtain the Hausdorff dimension, $h=2-2s$, for particles with fractional spins in the interval, $0\leq s \leq 0.5$, such that the manifold is characterized by a topological invariant given by, ${\cal W}=h+2s-2p$. This object is related to fractal properties of the path swept out by fractional spin particles, the spin of these particles, and the genus (numb

Bernd A. Kniehl, Gustav Kramer

Approximately taking into account the higher-order effects due to multiple-gluon initial-state radiation, we extract from the latest Tevatron data of prompt J/psi hadroproduction the leading colour-octet matrix elements within the nonrelativistic-QCD (NRQCD) factorization formalism proposed by Bodwin, Braaten, and Lepage. We find that the matrix elements whi

N. O. Agasian

The gluon fields screening in the stochastic vacuum of gluodynamics is studied. The effective action is derived for the instanton interacting with nonperturbative fields. Quantum nonperturbative effects are shown to affect greatly the shape of instanton. The power asymptotics x^{-2} of the classical &#34;instanton&#39;s profile function&#34; at large distanc

J. Gasser, M. E. Sainio

We consider chiral perturbation theory in the meson sector at order $E^6$. In the terminology of the external field technique, the two--loop graphs so generated are of the sunset type. We discuss the evaluation of several of these in the case where the masses of the particles running in the loops are equal. In particular, we present integral representations

L. Dixon, Z. Kunszt, A. Signer

We present the one-loop QCD corrections to the helicity amplitudes for the processes $q\qb \to W^+ W^-, Z Z, W^\pm Z, W^\pm γ$, or $Z γ$, including the subsequent decay of each massive vector boson into a pair of leptons. We also give the corresponding tree-level amplitudes with an additional gluon radiated off the quark line. Together, these amplitudes prov

Jong Chul Lee, Kang Young Lee

We explore phenomenologies of the topflavour model for the LEP experiment at $m_{_Z}$ scale. Implications of the model on the $Z$ peak data are studied in terms of the precision variables $ε_i$&#39;s.

Kang Young Lee, Jong Chul Lee

We explore the impact of topflavour model to $B-\bar{B}$ mixings and rare decays of $B$ mesons. By the flavour-changing neutral current interactions of this model, the $B-\bar{B}$ mixing amplitudes are substantially affected while it is hard to investigate the effects on rare decays. Violation of the unitarity of the CKM matrix is also discussed. We find tha

Mark B. Wise

Exclusive semileptonic B decays are discussed. The emphasis is on using semileptonic decays to determine |V_{ub}| and |V_{cb}|. Recent progress in our understanding of B semileptonic decays to excited charmed mesons is also reviewed.

Stefan Dittmaier

High-precision predictions for W-production processes are complicated by the instability of the W bosons, requirements of gauge invariance, and the necessity to include radiative corrections. Salient features and recent progress concerning these issues are discussed for the process ee->WW->4f.

Jeffrey E. Mandula

This lecture describes the treatment of heavy quarks in lattice QCD by implementing the Isgur-Wise limit. The method is briefly discussed, and some of the special features of the resulting theory are highlighted. We emphasize issues of the renormalization of the effective theory. The formulation permits a calculation of heavy quark processes even when the mo

S. Bernreuther et al

The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibra

Luis O. Pimentel, César Mora

The Wheeler-DeWitt equation is solved for some scalar-tensor theories of gravitation in the case of homogeneous and isotropic cosmological models.We present general solutions corresponding to cosmological term: (i)λ(ϕ)=0$ and $(ii) λ(ϕ)=qϕ$.

Victor Berezin

The quantum black hole model with a self-gravitating spherically symmetric thin dust shell as a source is considered. The shell Hamiltonian constraint is written and the corresponding Schroedinger equation is obtained. This equation appeared to be a finite differences equation. Its solutions are required to be analytic functions on the relevant Riemannian su

Damien J. Holden, David Wands

We present an autonomous phase-plane describing the evolution of Friedmann-Robertson-Walker models containing a perfect fluid (with barotropic index gamma) in Brans-Dicke gravity (with Brans-Dicke parameter omega). We find self-similar fixed points corresponding to Nariai&#39;s power-law solutions for spatially flat models and curvature-scaling solutions for

Kengo Maeda, Akihiro Ishibashi, Makoto Narita

We test the chronology protection conjecture in classical general relativity by investigating finitely vicious space-times. First we present singularity theorems in finitely vicious space-times by imposing some restrictions on the chronology violating sets. In the theorems we can refer to the location of an occurring singularity and do not assume any asympto

Rodolfo Gambini, Jorge Griego, Jorge Pullin

We show that Vassiliev invariants of knots, appropriately generalized to the spin network context, are loop differentiable in spite of being diffeomorphism invariant. This opens the possibility of defining rigorously the constraints of quantum gravity as geometrical operators acting on the space of Vassiliev invariants of spin nets. We show how to explicitly

Bahram Mashhoon

The inertial and gravitational properties of intrinsic spin are discussed and some of the recent work in this area is briefly reviewed. The extension of relativistic wave equations to accelerated systems and gravitational fields is critically examined. A nonlocal theory of accelerated observers is presented and its predictions are compared with observation.

Donald Marolf

This summary was prepared for the proceedings of the GR15 conference in Pune, India in Dec. 1997.

D. V. Averin

The manuscript presents an overview of recent developments in theory of multiple Andreev reflections in Josephson junctions with arbitrary transparency and arbitrary quasiparticle dispersion in the electrodes.

M. Greven, R. J. Birgeneau

We present a Monte Carlo study of the correlation length $ξ$ of randomly diluted antiferromagnetic Heisenberg ladders, composed of two spin--1/2 chains. For weak and intermediate inter--chain couplings, $J_{\bot}/J \leq 1$, we find an enhancement of correlations that is strongest for a fraction $z^* \approx J_{\bot}/(8J)$ of dilutants. We are able to access