August 1998 arXiv papers — page 8

Jacek Pawelczyk, Stefan Theisen

We compute $O(\alpha'^3)$ corrections to the $AdS_5\times S^5$ black hole metric. We find that the radius of the $S^5$ depends on the radial $AdS_5$ coordinate. This completes the computation of Gubser, Klebanov and Tseytlin (hep-th/9805156). The fact that the metric no longer factorizes should modify the value of the Wilson line at finite temperature and th

Nick E. Mavromatos, Richard J. Szabo

We describe the structure of the moduli space of $σ$-model couplings for the worldsheet description of a system of $N$ D-particles, in the case that the couplings are represented by a pair of logarithmic recoil operators. We derive expressions for the canonical momenta conjugate to the D-particle couplings and the Zamolodchikov metric to the first few orders

Fuad M. Saradzhev

For the generalized chiral Schwinger model defined on the circle, a direct calculation of the zero curvature part of the vacuum Berry phase connection is given. Although this part does not contribute to the curvature, it is shown to attach several features to the total connection and to produce a physical background of linearly rising electric fields.

Seong-Youl Choi, Manuel Drees

We discuss signals for CP-violation in $μ^+ μ^- \to \tilde τ_i^- \tilde τ_j^+$, where $i,j = 1,2$ label the two scalar $τ$ mass eigenstates. We assume that these reactions can proceed through the production and decay of the heavy neutral Higgs bosons present in supersymmetric models. CP-violation in the Higgs sector can be probed through a rate asymmetry eve

A. Leike, S. Riemann, T. Riemann

We derive a method for a common treatment of Z' exchange, QED corrections, and weak loops. It is based on the form factor approach to the description of weak loop corrections to partial Z widths and cross sections. Problems connected with ZZ' mixing are discussed with special care. Our theoretical results are applied to the package ZFITTER. We demons

A. Bialas

Summary talk at the VIIIth International Workshop on Multiparticle Production "Correlations and Fluctuations '98" held at Matrahaza, Hungary, from 14th till 21st of June 1998.

J. Bluemlein, A. Leike, T. Riemann

The study of ep-scattering at LEP x LHC offers an interesting opportunity to search for additional heavy neutral gauge bosons. We study the influence of radiative corrections, especially of the potentially large QED contributions, to the expected cross sections. These corrections are typically of the same order as the effect searched for or even larger and h

A. D. Martin, R. G. Roberts, W. J. Stirling, R. S. Thorne

We extend a recent global analysis of nucleon parton distributions carried out at next-to-leading order (NLO) in the MSbar scheme to provide distributions in the so-called DIS scheme. We pay particular attention to the translation of the heavy quark distributions in going from the MSbar to the DIS scheme. We repeat the global analysis at leading order (LO) a

R. Kirchner, S. Luckmann, I. Montvay, K. Spanderen

We report on our experience with the two-step multi-bosonic algorithm in a large scale Monte Carlo simulation of the SU(2) Yang-Mills theory with dynamical gluinos. First results are described on the low lying spectrum of bound states, the string tension and the gluino condensate.

E. -M. Ilgenfritz, A. Schiller, C. Strecha

Wave functions and the screening mass spectrum in the 3D SU(2)-Higgs model near to the phase transition line below the endpoint and in the crossover region are calculated. In the crossover region the changing spectrum versus temperature is examined showing the aftermath of the phase transition at lower Higgs mass. Large sets of operators with various extensi

Kevin Cahill, Gary Herling

We identify the artifact that causes confinement at strong coupling in compact U(1) lattice gauge theory and show that most of the string tension in compact SU(2) lattice gauge theory is due to plaquettes of negative trace.

Ronald J. Madaras

This talk at the XVIII International Conference on Physics in Collision, Frascati, Italy, June 17-19, 1998, presents CDF and D0 results on W and Z Boson Production Cross Sections, the W Boson Width, Rare W Boson Decays, Trilinear Gauge Boson Couplings, and the W Boson Mass.

The OPAL Collaboration, K. Ackerstaff et al

The spectral functions of the vector current and the axial-vector current have been measured in hadronic tau decays using the OPAL detector at LEP. Within the framework of the Operator Product Expansion a simultaneous determination of the strong coupling constant alpha_s, the non-perturbative operators of dimension 6 and 8 and of the gluon condensate has bee

Hyeong-Chan Kim

We present an exact treatment of the influences on a quantum scalar field in its Minkowski vacuum state induced by coupling of the field to a uniformly accelerated harmonic oscillator. We show that there are no radiation from the oscillator in the point of view of a uniformly accelerating observer. On the other hand, there are radiations in the point of view

Richard G. Gass, F. Paul Esposito, L. C. R. Wijewardhana, Louis Witten

We have investigated the behavior of three curvature invariants for Schwarzschild, Reissner-Nordstrøm, Kerr, and Kerr-Newman black holes. We have also studied these invariants for a Schwarzschild-de Sitter space-time, the $γ$ metric, and for a 2+1 charged dimensional black hole. The invariants are $I_{1}=R_{αβμν;λ}R^{αβμν;λ}$, $I_{2}=R_{μν;λ} R^{μν;λ}$, and

Philippos Papadopoulos, Jose A. Font

We develop and calibrate a new method for estimating the gravitational radiation emitted by complex motions of matter sources in the vicinity of black holes. We compute numerically the linearized curvature perturbations induced by matter fields evolving in fixed black hole backgrounds, whose evolution we obtain using the equations of relativistic hydrodynami

G. Stan, V. H. Crespi, M. W. Cole, M. Boninsegni

We explore the properties of atoms confined to the interstitial regions within a carbon nanotube bundle. We find that He and Ne atoms are of ideal size for physisorption interactions, so that their binding energies are much greater there than on planar surfaces of any known material. Hence high density phases exist at even small vapor pressure. There can res

I. Scott, H. -Th. Elze, T. Kodama, J. Rafelski

We draw attention to the fact that the popular but unproven hypothesis of shock-driven sonoluminescence is incompatible with the reported synchronicity of the single bubble sonoluminescence (SBSL) phenomenon. Moreover, it is not a necessary requirement, since we show that the sub-shock dynamic heating in gas bubble cavitation can lead to conditions required

A. Hanke, E. Eisenriegler, S. Dietrich

The behavior of mesoscopic particles dissolved in a dilute solution of long, flexible, and nonadsorbing polymer chains is studied by field-theoretic methods. For spherical and cylindrical particles the solvation free energy for immersing a single particle in the solution is calculated explicitly. Important features are qualitatively different for self-avoidi

Gianfranco Durin, Stefano Zapperi

We report experimental measurements of Barkhausen noise on Fe_{64}Co_{21}B_{15} amorphous alloy under tensile stress. We interpret the scaling behavior of the noise distributions in terms of the depinning transition of the domain walls. We show that stress induced anisotropy enhance the effect of short-range elastic interactions that dominate over long-range

Gene F. Mazenko

The continuity equations expressing conservation of string defect charge can be used to find an explicit expression for the string velocity field in terms of the order parameter in the case of an O(n) symmetric time-dependent Ginzburg-Landau model. This expression for the velocity is used to find the string velocity probability distribution in the case of ph

Uma Bhaumik, Indrani Bose

We consider two partially frustrated S = 1/2 antiferromagnetic spin systems on the triangular and pentagonal lattices. In an elementary plaquette of the two lattices, one bond has exchange interaction strength $α$ ($α\leq 1$) whereas all other bonds have exchange interaction strength unity. We show that for $α$ less than a critical value $α_{c}$, collinear N

Somendra M. Bhattacharjee, Sutapa Mukherji

A dimerized quantum Heisenberg or XY antiferromagnetic chain has a gap in the spectrum. We show that a weak incommensurate modulation around a dimerized chain produces a zero temperature quantum critical point. As the incommensuration wavelength is varied, there is a transition to a modulated gapless state. The critical behaviour is in the universality class

Y. Paltiel, D. T. Fuchs, E. Zeldov, Y. N. Myasoedov

Transport current distribution in clean 2$H$-NbSe$_{2}$ crystals is studied by measuring the self-induced magnetic field across the sample. Below $T_c$ most of the current flows at the edges of the crystals due to strong surface barriers, which are found to dominate the transport properties and the resistive transition. The measured critical current is deter

Ken-ichiro Imura

The paper has been withdrawn.

Cem Bozsahin

In relatively free word order languages, grammatical functions are intricately related to case marking. Assuming an ordered representation of the predicate-argument structure, this work proposes a Combinatory Categorial Grammar formulation of relating surface case cues to categories and types for correctly placing the arguments in the predicate-argument stru

Alexander S. Yeh, Marc B. Vilain

Determining the attachments of prepositions and subordinate conjunctions is a key problem in parsing natural language. This paper presents a trainable approach to making these attachments through transformation sequences and error-driven learning. Our approach is broad coverage, and accounts for roughly three times the attachment cases that have previously b

E. M. Shahverdiev

For the first time an example of hyperchaos synchronization with a zero driving variable using the system's parameters changes, proposed by L.Zonghua and C.Shigang (Phys.Rev.E, 55, 6651 (1997)) is presented. Also it has been indicated that in the case of a single variable driving put forward by A.Tamasevicius and A.Cenys, Phys.Rev.E, 55, 297 (1997) such

A. A. Panferov, S. N. Fabrika, T. Tomov

Results of spectroscopy of unusual symbiotic star MWC560 are presented. The data have been obtained from autumn 1990 to spring 1993. The high velocity absorption line profiles demonstrate their origin in a jet, directed closely to the line of sight. These absorptions are variable at a time-scale less than one day and with an amplitude of about 10%. The fast

J. S. Greaves, W. S. Holland, G. Moriarty-Schieven, T. Jenness

Dust emission around the nearby star epsilon Eridani has been imaged using a new submillimetre camera (SCUBA at the JCMT). At 850 microns wavelength a ring of dust is seen, peaking at 60 AU from the star and with much lower emission inside 30 AU. The mass of the ring is at least 0.01 Earth masses in dust, while an upper limit of 0.4 Earth masses in molecular

Ioannis Contopoulos, Demosthenes Kazanas

We show that the Poynting-Robertson drag effect in an optically thin advection-dominated accretion flow around active gravitating objects generates strong azimuthal electric currents which give rise to astrophysically significant magnetic fields. Although the mechanism is most effective in accreting compact objects, it seems very promising to also account fo

Chris Simpson

We investigate the recent claim by Qin et al. that the observed correlations (or lack thereof) between the core dominance parameter and the core and extended powers of samples of lobe- and core-dominated quasars is in contradiction with beaming models. Contrary to their conclusion, we find that their results are in perfect agreement with such models, and sup

R. A. Battye, E. P. S. Shellard

In the wide variety of axion cosmologies in which axion strings form, their radiative decay is the dominant mechanism for the production of axions, imposing a tight constraint on the axion mass. Here, we focus on the mechanism by which axions are produced in this scenario and, in particular, the key issue of the axion spectrum emitted by an evolving network

E. P. S. Shellard, R. A. Battye

We discuss the possible sources of dark matter axions in the early universe. In the standard thermal scenario, an axion string network forms at the Peccei-Quinn phase transition $T\sim \fa$ and then radiatively decays into a cosmological background of axions; to be the dark matter, these axions must have a mass $\ma \sim 100 μeV$ with specified large uncerta

F. Munyaneza, D. Tsiklauri, R. D. Viollier

We report here on a calculation of possible orbits of the fast moving infrared source S1 which has been recently observed by Eckart and Genzel (1997) near the Galactic center. It is shown that tracking of the orbit of S1 or any other fast moving star near Sgr A^* offers a possibility of distinguishing between the supermassive black hole and extended object s

S. De Rijcke, H. Dejonghe

Galaxy spectra are a rich source of kinematical information since the shapes of the absorption lines reflect the movement of stars along the line-of-sight. We present a technique to directly build a dynamical model for a galaxy by fitting model spectra, calculated from a dynamical model, to the observed galaxy spectra. Using synthetic spectra from a known ga

D. A. Smith, V. S. Dhillon

We critically re-examine the available data on the spectral types, masses and radii of the secondary stars in cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs), using the new catalogue of Ritter & Kolb (1998) as a starting point. We find there are 55 reliable spectral type determinations and only 14 reliable mass determinations of CV secondary

E. Covas, R. Tavakol

An important question regarding the study of mean field dynamo models is how to make precise the nature of their underlying dynamics. This is difficult both because relatively little is known about the dynamical behaviour of infinite dimensional systems and also due to the numerical cost of studying the related partial differential equations. As a first step

Markos Georganopoulos, Alan P. Marscher

The bright X-ray selected BL Lacertae object PKS 2155-304 has been the target of two intense multiwavelength campaigns, in November 1991 and in May 1994. Although the spectral energy distributions at both epochs were quite similar, the source exhibited two very distinct variability patterns that cannot be easily reconciled with homogeneous, one-zone jet mode

A. Tworkowski, E. Covas, R. Tavakol, A. Brandenburg

Calculations for mean field dynamo models (in both full spheres and spherical shells), with both algebraic and dynamic $α$--quenchings, show qualitative as well as quantitative differences and similarities in the dynamical behaviour of these models. We summarise and enhance recent results with extra examples. Overall, the effect of using a dynamic $α$ appear

Felix Ryde, Roland Svensson

The discovery (Liang & Kargatis 1996), that the peak energy of time-resolved spectra of gamma-ray burst (GRB) pulses decays exponentially with fluence, is analytically shown to imply that the time-integrated photon number spectrum of a pulse should have a unique shape, given by an underlying E^-1 behavior. We also show that the asymptotic low energy normaliz

J. Siebert, W. Brinkmann, S. A. Laurent-Muehleisen

We present recent ROSAT, ASCA and SAX observations of intermediate BL Lac objects (IBLs), i.e. BL Lacs which are located between high-energy and low-energy peaked BL Lac objects with respect to alpha_rx. Both the statistical properties of IBLs from the RGB sample and a detailed broad band X-ray spectral analysis of two objects (1424+2401, 1055+5644) point to

P. Goldoni, M. Vargas, A. Goldwurm, J. Paul

We present observations of the X-ray transient XTEJ1755-324 performed during summer 1997 with the XTE satellite and with the SIGMA hard X-ray telescope onboard the GRANAT observatory. The source was first detected in soft X-rays with XTE on July 25 1997 with a rather soft X-ray spectrum and its outburst was monitored in soft X-rays up to November 1997. On Se

C. M. Baugh, S. Cole, C. S. Frenk, A. J. Benson

Any realistic theory of galaxy formation must be set in the context of a model for the formation of structure in the universe. We describe a powerful approach -- semi-analytic modelling -- that combines a set of simple rules describing the gas processes involved in galaxy formation with a scheme to follow the hierarchical growth of dark matter haloes. Surpri

K. Senouci, N. Zekri, H. Bahlouli, A. K. Sen

The Kronig-Penney model is used to Study the effect of nonlinear interaction on the transmissive properties of both ordered and disordered chains. In the ordered case, the nonlinearity can either localize or delocalize the electronic states depending on both its sign and strength but there is a critical strength above which all the states are localized. In t

M. Spada, M. Salvati, F. Pacini

We study the variability properties at radio frequencies of the jets thought to be typical of Active Galactic Nuclei, i.e. bulk Lorentz factor Γ~ 10, and incoherent synchrotron emission. We assume that the radiating electrons are accelerated at shocks within the jet, and that these shocks have a suitable (conical) geometry. In our framework, we can reproduce

Rodolfo Casana, Sebastiao Alves Dias

We consider the detailed renormalization of two (1+1)-dimensional gauge theories which are quantized without preserving gauge invariance: the chiral and the "anomalous" Schwinger models. By regularizing the non-perturbative divergences that appear in fermionic Green's functions of both models, we show that the "tree level" photon propagat

Z. Nagy, Z. Trocsanyi

We show that the next-to-leading order perturbative prediction, matched with the next-to-leading logarithmic approximation for predicting both two-, three- and four-jet rates using the Durham jet-clustering algorithm, in the 0.001 < ycut < 0.1 range gives a very accurate description of the data obtained at the Large Electron Positron collider. This informati

A. Ya. Parkhomenko, A. D. Smirnov

Quark-gluon decays of heavy paraquarkonia $^1 S_0(\bar Q Q) \to \bar q q g$ are investigated with account of the masses of final quarks. The decay widths and the energy distributions of the final quarks and gluons are calculated in dependence on the relative quark masses. The strong collinear enhancement of the gluon energy distribution at the end of the spe

J. G. Russo

We construct supergravity backgrounds representing non-homogeneous compactifications of d=10,11 supergravities to four dimensions, which cannot be written as a direct product. The geometries are regular and approach $AdS_7\times S^4$ or $AdS_5\times S^5$ at infinity; they are generically non-supersymmetric, except in a certain &#34;extremal&#34; limit, where

Martin Lüscher

The axial anomaly in abelian lattice gauge theories is shown to be equal to a simple quadratic expression in the gauge field tensor plus a removable divergence term if the lattice Dirac operator satisfies the Ginsparg-Wilson relation. The theorem is a consequence of the locality, the gauge invariance and the topological nature of the anomaly and does not ref

S. Esposito, G. Mangano, G. Miele, O. Pisanti

We report the results of a detailed calculation of nucleon weak interactions relevant for the neutron to proton density ratio at the onset of primordial nucleosynthesis. Radiative electromagnetic corrections, finite nucleon mass terms, thermal radiative effects on weak processes and on neutrino temperature are taken into account to reduce the theoretical unc

A. A. Stanislavsky

It is shown that due to memory effects the complex behaviour of components in a stochastic system can be transmitted to macroscopic evolution of the system as a whole. Within the Markov approximation widely using in ordinary statistical mechanics, memory effects are neglected. As a result, a time-scale separation between the macroscopic and the microscopic l

Takuhiro Kitao, Kazutoshi Ohta, Nobuyoshi Ohta

We study three-dimensional gauge dynamics by using type IIB superstring brane configurations, which can be obtained from the M-theory configuration of M2-branes stretched between two M5-branes with relative angles. Our construction of brane configurations includes (p,q)5-brane and gives a systematic classification of possible three-dimensional gauge theories

J. Hashida, Y. Kiyo

We discuss polarized proton-positron scattering in the context of the excess of large $Q^2$ events at HERA. We define and estimate a polarized asymmetry to examine two scenarios, the contact interaction and the stop scenario with broken R-parity. This asymmetry exhibits a characteristic behavior depending on the scenarios. Thus the polarized experiment at HE

Simon Portegies Zwart, Chang-Hwan Lee, Hyun Kyu Lee

We present a phenomenological model to explain the light curves of gamma-ray bursts. In the model a black hole is orbited by a precessing accretion disc which is fed by a neutron star. Gamma-rays are produced in a highly collimated beam via the Blandford-Znajek mechanism. The gamma-ray beam sweeps through space due to the precession of the slaved accretion d

J. H. Kim, D. A. Harris

We extract a set of values for the Gross-Llewellyn Smith sum rule at different values of 4-momentum transfer squared ($Q^{2}$), by combining revised CCFR neutrino data with data from other neutrino deep-inelastic scattering experiments for $1 < Q^2 < 15 GeV^2/c^2$. A comparison with the order $α^{3}_{s}$ theoretical predictions yields a determination of $α_{

A. Camacho, A. Camacho-Galvan

We calculate the propagator of a particle caught in a Paul trap and subject to the continuous quantum measurement of its position. The probabilities of the measurement outputs, the possible trajectories of the particle, are also found. This enables us to propose a series of experiments that would allow to confront the predictions of one of the models that de

B. G. Sidharth

We discuss the recent model of a Quantum Mechanical Black Hole (QMBH) which describes the most fundamental known particles, the leptons and approximately the quarks in terms of the Kerr-Newman Black Hole with a naked singularity shielded by Zitterbewegung effects. This goes beyond the Zitterbewegung and self interaction models of Barut and Bracken, Hestenes,

Kai Druhl

This paper presents a detailed numerical study of the effect of focusing on the conversion efficiency of low-loss singly-resonant parametric oscillators with collinear focusing of pump and signal. Results are given for the maximal pump depletion and for pump power levels required for various amounts of depletion, as functions of pump and signal confocal para

G. F. Gribakin, A. A. Gribakina, V. V. Flambaum

We show that the spectrum and eigenstates of open-shell multicharged atomic ions near the ionization threshold are chaotic, as a result of extremely high level densities of multiply excited electron states (1000 levels per eV in Au 24+) and a strong configuration mixing. This complexity enables one to use statistical methods to analyze the system. The orbita

S. Hobai, Z. Fazakas

The paper describes the effect of anion I-3 on thermotropic mesomorphism of fully hydrated dipalmitoylphosphatidylcholine bilayers. The biphasic behaviour of melting temperature - I-3 concentration dependence and the increase of DELTA T values with I-3 concentration (DELTA T = melting temperature - freezing temperature) suggest the appearance of interdigitat

Elena A. Ostrovskaya, Yuri S. Kivshar, Zhigang Chen, Mordechai Segev

We describe a physical mechanism for creating multi-soliton bound states where solitons are glued together by attraction between the beams they guide, `solitonic gluons&#39;. We verify the concept of the solitonic gluons experimentally, observing a suppression of the repulsion between dark solitons due to an attractive force between bright guided beams.

A. Deveikis, G. Kamuntavicius

A new method for elimination of the &#39;spurious&#39; states comprising reguirement of translational invariance and simplicity of the enumeration scheme of antisymmetric A-particle states has been developed. The method presented enables one to project off the space of purely spurious antisymmetric A-particle oscillator functions with singled out dependence

A. Deveikis, G. Kamuntavicius

A new method for calculation of shell model intrinsic density matrices, defined as two-particle density matrices integrated over the centre-of-mass position vector of two last particles and complemented with isospin variables, has been developed. The intrinsic density matrices obtained are completely antisymmetric, translation-invariant, and do not employ a

A. Deveikis, G. Kamuntavicius

A new procedure for the calculation of shell model coefficients of fractional parentage has been developed. This procedure is free of numerical diagonalization, orthogonalization, and even of grop theoretical classification of antisymmetric states.

Masayuki Matsuzaki

We study two kinds of Dirac sea effects on the $^1S_0$ pairing gap in nuclear matter based on the relativistic Hartree approximation to quantum hadrodynamics and the Gor&#39;kov formalism. We show that the vacuum fluctuation effect on the nucleon effective mass is more important than the direct coupling between the Fermi sea and the Dirac sea due to the pair

Vadim V. Varlamov

Relation between generalized Weierstrass representation for conformal immersion of generic surfaces into three-dimensional space and Lax-Phillips scattering theory for automorphic functions is considered.

Erik Andersen

We prove necessary and sufficient conditions for completeness of a rational vector field on C^n minus n hyperplanes in general position (n>1).

Chongying Dong, Kiyokazu Nagatomo

We give a complete description of the full automorphism group of a lattice vertex operator algebra, determine the twisted Zhu&#39;s algebra for the automorphism lifted from the -1 isometry of the lattice and classify the corresponding irreducible twisted modules through the twisted Zhu algebra.

Joerg Winkelmann

Rosay and Rudin constructed examples of discrete subsets of C^n with remarkable properties. We generalize these constructions from C^n to arbitrary Stein manifolds. We prove: Given a Stein manifold X and a affine variety V of the same dimension there exists a discrete subset D in X such that (1) X-D is measure hyperbolic, (2) f(V) intersects D for every non-

I. Heckenberger, A. Schueler

For the 9-dimensional bicovariant differential calculi on the Hopf algebra $O(O_q(3))$ several kinds of exterior algebras are examined. The corresponding dimensions, bicovariant subbimodules and eigenvalues of the antisymmetrizer are given. Exactly one of the exterior algebras studied by the authors has a unique left invariant form with maximal degree.

F. Antonuccio, H. C. Pauli, S. Pinsky, S. Tsujimaru

We consider the 1+1 dimensional N = (2,2) supersymmetric matrix model which is obtained by dimensionally reducing N = 1 super Yang-Mills from four to two dimensions. The gauge groups we consider are U(Nc) and SU(Nc), where Nc is finite but arbitrary. We adopt light-cone coordinates, and choose to work in the light-cone gauge. Quantizing this theory via Discr

N. Ilieva, W. Thirring

Solutions to the Thirring model are constructed in the framework of algebraic QFT. It is shown that for all positive temperatures there are fermionic solutions only if the coupling constant is $λ= \sqrt{2(2n+1)π}, n\in \bf N$, otherwise solutions are anyons. Different anyons (which are uncountably many) live in orthogonal spaces, so the whole Hilbert space b

S. A. Bulgadaev

A general theory of the Berezinsky-Kosterlitz-Thouless (BKT) type phase transitions in low-dimensional systems is proposed. It is shown that in d-dimensional case the necessary conditions for it can take place are 1) conformal invariance of kinetic part of model action and 2) vacuum homotopy group $π_{d-1}$ must be nontrivial and discrete. It means a discret

Masud Chaichian, Tatsuo Kobayashi

We study softly broken N=1 supersymmetric QCD with the gauge group $SU(N_c)$ and $N_f$ flavors of quark pairs. We investigate vacuum structure of the theory with generic soft supersymmetry breaking terms. Trilinear soft breaking terms play an essential role in determining vacua. For $N_f=N_c+1$, chiral symmetry is broken for a sufficiently large magnitude of

Gerard &#39;t Hooft

Explicit expressions are considered for the generating functions concerning the number of planar diagrams with given numbers of 3- and 4-point vertices. It is observed that planar renormalization theory requires diagrams with restrictions, in the sense that one wishes to omit `tadpole&#39; inserions and `seagull&#39; insertions; at a later stage also self-en

Andrzej Z. Gorski, Jacek Szmigielski

We construct a class of representations of the Heisenberg algebra in terms of the complex shift operators subject to the proper continuous limit imposed by the correspondence principle. We find a suitable Hilbert space formulation of our construction for two types of shifts: (1) real shifts, (2) purely imaginary shifts. The representations involving imaginar

Rafal Moderski, Marek Rogatko

It is argued that an electronically charged dilaton black hole can support a long range field of a Nielsen-Olesen string. Combining both numerical and perturbative techniques we examine the properties of an Abelian-Higgs vortex in the presence of the black hole under consideration. Allowing the black hole to approach extremality we found that all fields of t

Andrei A. Bytsenko, Shin&#39;ichi Nojiri, Sergei D. Odintsov

Dilaton coupled electromagnetic field is essential element of low-energy string effective action or it may be considered as result of spherical compactification of Maxwell theory in higher dimensions. The large $N$ and large curvature effective action for $N$ dilaton coupled vectors is calculated. Adding such quantum correction to classical dilaton gravity a

Holger B. Nielsen, Masao Ninomiya

It is proposed to make formulation of second quantizing a bosonic theory by generalizing the method of filling the Dirac negative energy sea for fermions. We interpret that the correct vacuum for the bosonic theory is obtained by adding minus one boson to each single particle negative energy states while the positive energy states are empty. The boson states

M. Kamela, C. P. Burgess

Closed forms are derived for the effective actions for free, massive spinless fields in anti-de Sitter spacetimes in arbitrary dimensions. The results have simple expressions in terms of elementary functions (for odd dimensions) or multiple Gamma functions (for even dimensions). We use these to argue against the quantum validity of a recently-proposed dualit

K. A. Oganessyan, H. R. Avakian, N. Bianchi, A. M. Kotzinian

We investigate the $sin ϕ$ azimuthal asymmetry in the semi-inclusive deep-inelastic lepton scattering off longitudinally polarized nucleon target arising from the time reversal odd structures. The order 1/Q contributions of the leading twist and twist-three distribution and fragmentation functions to that asymmetry for the certain kinematical conditions are

V. Barger, T. J. Weiler, K. Whisnant

By combining experimental constraints from atmospheric and solar neutrino oscillations and the tritium beta decay endpoint, we infer upper limits of 4.4 eV on the $ν_μ$ and $ν_τ$ masses, if the universe consists of three neutrinos. For hierarchical mass spectra $m_3 \gg m_1, m_2$ or $m_3 \simeq m_2 \gg m_1$ we infer that $m_{ν_α} \lsim 0.08$ eV for $α= e, μ,

D. Kharzeev, R. D. Pisarski, M. H. G. Tytgat

We consider the topological susceptibility for an SU(N) gauge theory in the limit of a large number of colors, $N \to \infty$. At nonzero temperature, the behavior of the topological susceptibility depends upon the order of the deconfining phase transition. The most interesting possibility is if the deconfining transition, at $T=T_d$, is of second order. The

R. N. Faustov, A. Karimkhodzhaev, A. P. Martynenko

The contribution of hadronic vacuum polarization (HVP) to the hyperfine splitting of the muonium ground state is evaluated with the account of modern experimental data on the cross section of $e^+e^- \to$ annihilation into hadrons.

P V Landshoff

Within the next few years experiments at RHIC and the LHC will seek to create in the laboratory a quark-gluon plasma, the phase of matter through which the Universe passed very early in its life. It is believed that the plasma will survive long enough to reach thermal equilibrium. I give an introduction to the formalism of thermal field theory, the combinati

Howard Baer, P. G. Mercadante, Xerxes Tata

Because of their Yukawa interactions, third generation squarks may be substantially lighter than those of the first two generations. Assuming that $\tb_1 \to b\tz_1$ and $\tz_1$ escapes experimental detection, we show that experiments at the Main Injector upgrade (integrated luminosity of $2 fb^{-1}$) of the Tevatron should be sensitive to $b$-squark masses

M. Beneke, F. Maltoni, I. Z. Rothstein

We compute the decay rates and $H$-energy distributions of $B$ mesons into the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave charmonia, at next-to-leading order in the strong coupling. We find that a significant fraction of the observed $J/ψ$, $ψ&#39;$ and $χ_c$ must be produced through $c\bar{c}$ pairs in a colour octet state and s

M. E. Carrington, Hou Defu, M. H. Thoma

We present an extension of the HTL resummation technique to non-equilibrium situations, starting from the real time formalism in the Keldysh representation. As an example we calculate the HTL photon self energy, from which we derive the resummed photon propagator. This propagator is applied to the computation of the interaction rate of a hard electron in a n

Shigemi Ohta, Matthew Wingate

In response to recently renewed interests in SU(N) pure-gauge dynamics with large N, both from M/string duality and from finite-temperature QCD phase structure, we calculate string tensions acting between the fundamental 4, diquark 6 and other color charges in SU(4) pure-gauge theory at temperatures below the deconfining phase change and above the bulk phase

M. Anikina, L. Chkhaidze, T. Djobava, V. Garsevanishvili

Light-front analysis of pi^{-} mesons in Mg-Mg collisions is carried out. The phase space of secondary pions is naturally divided into two parts in one of which the thermal equilibration assumption seems to be in a good agreement with data. Corresponding temperatures are extracted and compared to the results of other experiments. The experimental results hav

P. N. Burrows

A review is given of latest results on tests of the flavour independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios alpha_s^b/alpha_s^uds and alpha_s^c/alpha_s^uds are found to be consistent with unity. Determinations o

The OPAL Collaboration, K. Ackerstaff et al

The Michel parameters of the leptonic tau decays are measured using the OPAL detector at LEP. The Michel parameters are extracted from the energy spectra of the charged decay leptons and from their energy-energy correlations. A new method involving a global likelihood fit of Monte Carlo generated events with complete detector simulation and background treatm

S. Mignemi

We study a solution of the Einstein-Gauus-Bonnet theory in 5 dimensions coupled to a Maxwell field, whose euclidean continuation gives rise to an instanton describing black hole pair production. We also discuss the dual theory with a 3-form field coupled to gravity.

Massimo Giovannini

The dynamical symmetries of hot and electrically neutral plasmas in a highly conducting medium suggest that, after the epoch of the electron-positron annihilation, magnetohydrodynamical configurations carrying a net magnetic helicity can be present. The simultaneous conservation of the magnetic flux and helicity implies that the (divergence free) field lines

Dietmar Klemm

We present a class of exact solutions of Weyl conformal gravity, which have an interpretation as topological black holes. Solutions with negative, zero or positive scalar curvature at infinity are found, the former generalizing the well-known topological black holes in anti-de Sitter gravity. The rather delicate question of thermodynamic properties of such o

Nikolas Provatas, Nigel Goldenfeld, Jonathan Dantzig

We study the evolution of solidification microstructures using a phase-field model computed on an adaptive, finite element grid. We discuss the details of our algorithm and show that it greatly reduces the computational cost of solving the phase-field model at low undercooling. In particular we show that the computational complexity of solving any phase-boun

Boldizsar Janko, Ioan Kosztin, K. Levin, M. R. Norman

We argue that incoherent pair tunneling in a cuprate superconductor junction with an optimally doped superconducting and an underdoped normal lead can be used to detect the presence of pairing correlations in the pseudogap phase of the underdoped lead. We estimate that the junction characteristics most suitable for studying the pair tunneling current are clo

Mark Bowick, Alex Travesset

We analyze the tubular phase of self-avoiding anisotropic crystalline membranes. A careful analysis using renormalization group arguments together with symmetry requirements motivates the simplest form of the large-distance free energy describing fluctuations of tubular configurations. The non-self-avoiding limit of the model is shown to be exactly solvable.