May 1997 arXiv papers — page 2

Kota Yoshioka

Let M(v) be the moduli of stable sheaves on K3 surfaces X of Mukai vector v. If v is primitive, than it is expected that M(v) is deformation equivalent to some Hilbert scheme and weight two hogde structure can be described by H^*(X,Z). These are known by Mukai, O'Grady and Huybrechts if rank is 1 or 2, or the first Chern class is primitive. Under some co

Eung Jin Chun, Haewon Lee, Won Sik l'Yi

Under the assumption that all the gauge groups in supersymmetric theories unify at the fundamental scale, the numbers and the mass scales of messenger quarks and leptons, as well as the beta-function coefficient of the sector for dynamical supersymmetry breaking are constrained depending on various gauge mediation mechanisms. For this, we use one-loop renorm

Eli Waxman

The recent detection of delayed X-ray and optical emission, ``afterglow,'' associated with gamma-ray bursts (GRBs) supports models, where the bursts are produced by relativistic expanding blastwaves, ``fireballs,'' at cosmological distances. The detection of absorption lines in the optical afterglow of the GRB of 8 May 1997 confirms that the

Minoru Wakimoto

In this note, we calculate the Poincaré series of elliptic Weyl groups of type $A^{(1,1)}_1$ and $A^{(1,1) \ast}_1$ and show that they have a simple expression.

W. Bulla, F. Gesztesy, H. Holden, G. Teschl

Combining algebro-geometric methods and factorization techniques for finite difference expressions we provide a complete and self-contained treatment of all real-valued quasi-periodic finite-gap solutions of both the Toda and Kac-van Moerbeke hierarchies. In order to obtain our principal new result, the algebro-geometric finite-gap solutions of the Kac-van M

Dinesh Kumar Srivastava

The present status of theoretical expectations of studies of single photons from relativistic heavy ion collisions is discussed. It is argued that the upper limit of single photon radiation from S+Au collisions at CERN SPS obtained by the WA80 collaboration perhaps rules out any reasonable description of the collision process which does not involve a phase t

Christos A. Athanasiadis

A hyperplane arrangement is said to satisfy the ``Riemann hypothesis'' if all roots of its characteristic polynomial have the same real part. This property was conjectured by Postnikov and Stanley for certain families of arrangements which are defined for any irreducible root system and was proved for the root system $A_{n-1}$. The proof is based on

Peter Ebenfelt

We consider the problem of describing the local biholomorphic equivalence class of a real-analytic hypersurface $M$ at a distinguished point $p_0\in M$ by giving a normal form for such objects. In order for the normal form to carry useful information about the biholomorphic equivalence class, we shall require that the transformation to normal form is unique

J. A. Minahan, D. Nemeschansky, N. P. Warner

We use the effective action of the $E_n$ non-critical strings to study its BPS spectrum for $0 \le n \le 8$. We show how to introduce mass parameters, or Wilson lines, into the effective action, and then perform the appropriate asymptotic expansions that yield the BPS spectrum. The result is the $E_n$ character expansion of the spectrum, and is equivalent to

James T. Wheeler

The dimensional properties of fields in classical general relativity lead to a tangent tower structure which gives rise directly to quantum mechanical and quantum field theory structures without quantization. We derive all of the fundamental elements of quantum mechanics from the tangent tower structure, including fundamental commutation relations, a Hilbert

P. Bowcock, M. Hayes, A. Taormina

We calculate characters and supercharacters for irreducible, admissible representations of the affine superalgebra sl(2|1) in both the Ramond and Neveu-Schwarz sectors and discuss their modular properties in the special case of level k=-1/2. We also show that the non-degenerate integrable characters coincide with some N=4 superconformal characters.

Robert Carroll

For certain situations relations are indicated between the space-wave function duality of Faraggi-Matone, enhanced dispersionless KdV, and Whitham dynamics for appropriate hyperelliptic Riemann surfaces related to Seiberg-Witten theory. This paper gives refinements of hep-th/9702138 and some new ideas.

Robert Marnelius

Talk at the International Workshop "New Non Perturbative Methods and Quantization on the Light Cone", Les Houches, France, Feb.24-March 7, 1997

Paolo Aschieri

We review the construction of the multiparametric inhomogeneous orthogonal quantum group ISO_qr(N) as a projection from SO_qr(N+2), and recall the conjugation that for N=4 leads to the quantum Poincare group. We study the properties of the universal enveloping algebra U_qr(iso(N)), and give an R-matrix formulation. A quantum Lie algebra and a bicovariant dif

S. Brodsky, H-C Pauli, S. Pinsky

We discuss the light-cone quantization of gauge theories as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a computer. The light-cone Fock state expansion of wavefunctions provides a precise definition of the parton model and a general calc

K. D. Anderson, D. A. Ross, M. G. Sotiropoulos

Starting from the dipole representation of small-$x$ evolution we implement the running of the coupling in a self-consistent way. This results in an evolution equation for the dipole density in Borel $(b)$ space. We show that the Borel image of the dipole density is analytic in the neighbourhood of $b=0$ and that it is equal to the BFKL solution at $b=0$. We

Stephen C. Davis, Anne-Christine Davis, Warren B. Perkins

The zero modes and current carrying capability of a cosmic string formed at one phase transition can be modified at subsequent phase transitions. A new, generalised index theorem is derived that is applicable to theories with multiple phase transitions. This enables us to investigate the fate of string zero modes during sequences of phase transitions in a va

J. Bordes, H. M. Chan, J. Faridani, J. Pfaudler

Air showers observed with $E > 10^{20}$ eV pose a problem since protons at such energies cannot survive a long journey through the 2.7 K microwave background. It is suggested that they are initiated instead by neutrinos which become strongly interacting through exchanges of gauge bosons associated with generation-changing neutral currents, a suggestion which

Xiao-Gang He, G. Valencia

We study the Delta I =3/2 and Delta S =2 amplitudes for hyperon decays of the form (B to B(prime) pion) at lowest order in chiral perturbation theory. At this order, the Delta I=3/2 amplitudes depend on only one constant. We extract the value of this constant from experiment and find a reasonable description of these processes within experimental errors. The

Paul H. Frampton

The aspon model spontaneously breaks CP symmetry and makes qualitatively different predictions for CP asymmetries in B decay from the KM mechanism of the Standard Model. It further predicts the existence of the aspon gauge boson and of heavy long-lived quarks, both lying below 1TeV in mass.

G. Grunberg

Standard power-behaved contributions in QCD arising from non-perturbative effects at low scale can be described, as shown by Dokshitzer, Marchesini and Webber, with the notion of an infrared regular effective coupling. In their approach, a non-perturbative contribution to the coupling, essentially restricted to low scales, parametrizes the non-perturbative p

J. Blümlein, B. Geyer, D. Robaschik

The general evolution kernels of the twist 2 light-ray operators for unpolarized and polarized deep inelastic scattering are calculated in ${\cal O}(α_s)$. From these evolution kernels a series of special evolution equations can be derived, among them the Altarelli-Parisi equations and the evolution equation for the meson wave function. In the case of twist

I. T. Dyatlov

If the hierarchy of quark masses comes out of simultaneous dynamical chiral and flavor symmetry breakings, it is inevitably accompanied by the flavor mixing. Therefore, these phenomena, independent in the standard model and in many of its generalizations, become related since they appear out of the same dynamics. The features of that high energy dynamics may

Aiichi Iwazaki

We show that axion domain walls gain spontaneous magnetization in early universe by trapping either electrons or positrons with their spins polarized. The reason is that the walls produces an attractive potential for these particles. We argue that the wall bounded by an axionic superconducting string leaves a magnetic field after its decay. We obtain a field

C. T. H. Davies

I review recent results for heavy-heavy spectroscopy using Lattice NRQCD. The NRQCD collaboration reports that spin-independent splittings for the $Υ$ are scaling for a sensible range of $β$ values in the quenched approximation. Spin-dependent splittings are not, if the scale is set by spin-independent splittings. Results which include higher order spin-depe

I. M. Barbour, S. E. Morrison, E. G. Klepfish, J. B. Kogut

We study QCD at non-zero quark density, zero temperature, infinite coupling using the Glasgow algorithm. An improved complex zero analysis gives a critical point μ_c in agreement with that of chiral symmetry restoration computed with strong coupling expansions, and monomer-dimer simulations. We observe, however, two unphysical critical points: the onset for

Michele Maggiore, Riccardo Sturani

We discuss the generation and evolution of density perturbations during the large curvature phase of string cosmology. We find that perturbations in the scalar components of the metric evolve with cosmic time as $\exp (γH_st)$ where $H_s$ is the Hubble constant during the string phase and $γ$ is a constant which is determined by an algebraic equation involvi

Shijun Yoshida, Yasufumi Kojima

We have calculated the non-radial oscillation in slowly rotating relativistic stars with the Cowling approximation. The frequencies are compared with those based on the complete linearized equations of general relativity. It is found that the results with the approximation differ by less than about $20 %$ for typical relativistic stellar models. The approxim

Ronald Fintushel, Ronald J. Stern

In this paper we introduce a technique, called rim surgery, which can change a smooth embedding of an orientable surface of positive genus and nonnegative self-intersection in a smooth 4-manifold while leaving the topological embedding unchanged.

Jeffrey M. Harris, P. J. White, Z. -X. Shen, H. Ikeda

We report angle-resolved photoemission spectra both above and below T_c in the single-plane cuprate superconductor Bi_2Sr_{2-x}La_xCuO_{6+d}. The superconducting state measurements show a highly anisotropic excitation gap with a maximum magnitude smaller than that of the bilayer compound Bi_2Sr_2CaCu_2O_8 by a factor of 3. For a range of doping, the gap pers

Xiaoqun Wang

A spin-1/2 magnetic impurity coupled to a one-dimensional correlated electron system have been studied by applying the density renormalization group method. The Kondo temperature is substantially enhanced by strong repulsive interactions in the chain, but changes non-monotonically in the case of electron attraction. The magnetization of the impurity at zero-

Xiaoqun Wang, Tao Xiang

The transfer matrix DMRG method for one dimensional quantum lattice systems has been developed by considering the symmetry property of the transfer matrix and introducing the asymmetric reduced density matrix. We have evaluated a number of thermodynamic quantities of the anisotropic spin-1/2 Heisenberg model using this method and found that the results agree

Thomas Vojta

We investigate how a quenched random field influences the damage spreading transition in kinetic Ising models. To this end we generalize a recent master equation approach and derive an effective field theory for damage spreading in random field systems. This theory is applied to the Glauber Ising model with a bimodal random field distribution. We find that t

Pragya Shukla

The wavefunctions in phase-space representation can be expressed as entire functions of their zeros if the phase space is compact. These zeros seem to hide a lot of relevant and explicit information about the underlying classical dynamics. Besides, an understanding of their statistical properties may prove useful in the analytical calculations of the wavefun

Parongama Sen, Purusattam ray, Bikas K. Chakrabarti

We report exact numerical diagonalization results of the infinite-range Ising spin glass in a transverse field $Γ$ at zero temperature. Eigenvalues and eigenvectors are determined for various strengths of $Γ$ and for system sizes $N \le 16$. We obtain the moments of the distribution of the spin-glass order parameter, the spin-glass susceptibility and the mas

Matthias Vojta, Klaus W. Becker

We investigate the dynamical charge-charge correlation function and the optical conductivity in weakly doped antiferromagnets using Mori-Zwanzig projection technique. The system is described by the two-dimensional t-J model. The arising matrix elements are evaluated within a cumulant formalism which was recently applied to investigate magnetic properties of

T. Nattermann

A review is given on some recent developments in the theory of the Ising model in a random field. This model is a good representation of a large number of impure materials. After a short repetition of earlier arguments, which prove the absence of ferromagnetic order in $d\le 2$ space dimensions for uncorrelated random fields, we consider different random fie

A. Misra, B. K. Chakrabarti

In this communication we report the existence of a dynamic ``spin-reversal'' transition in an Ising system perturbed by a pulsed external magnetic field. The transition is achieved by tuning the strength ($h_p$) and/or the duration ($Δt$) of the pulse which is applied in a direction opposite to the existing order. We have studied this transition in t

Yorick Wilks, Mark Stevenson

Sense tagging, the automatic assignment of the appropriate sense from some lexicon to each of the words in a text, is a specialised instance of the general problem of semantic tagging by category or type. We discuss which recent word sense disambiguation algorithms are appropriate for sense tagging. It is our belief that sense tagging can be carried out effe

Ilana M. Harrus, John P. Hughes, K. P. Singh, K. Koyama

(Abridged) We have investigated two evolutionary scenarios advanced to explain the centrally-brightened X-ray morphology of the supernova remnant (SNR) W44: (1) a model involving the slow thermal evaporation of clouds engulfed by a supernova blast wave as it propagates though a clumpy interstellar medium (ISM), and (2) a hydrodynamical simulation of a blast

Ulrich Kolb, Andrew King, Hans Ritter, Juhan Frank

We consider the evolutionary state of the black-hole X-ray source GRO J1655-40 in the context of its transient nature. Recent optical observations show that the donor in GRO J1655-40 is an intermediate-mass star (~ 2.3 solar masses) crossing the Hertzsprung gap. Usually in such systems the donor's radius expansion drives a near-Eddington or super-Eddingt

Norman K. Glendenning, S. Pei, F. Weber

The conversion of nuclear matter to quark matter in the core of a rotating neutron star alters its moment of inertia. Hence the epoch over which conversion takes place will be signaled in the spin-down "signal_prl.tex" 581 lines, 22203 characters characteristics of pulsars. We find that an observable called the braking index should be easily measurab

Frank P. Pijpers

From the observing campaigns of a number of helioseismic telescope networks such as the Global Oscillation Network Group (GONG) and also from the Solar Heliospheric Observatory satellite (SoHO), helioseismologists now have data on in excess of 20000 oscillation frequencies of the modes known collectively as the 5 minute oscillations. Depending on the order a

G. Henri, G. Pelletier

We present a model of accretion disk where the disk luminosity is entirely due to the reprocessing of hard radiation impinging on the disk. The hard radiation itself is emitted by a hot point source above the disk, that could be physically realized by a strong shock terminating an aborted jet. This hot source contains ultrarelativistic leptons scattering the

P. O. Petrucci, G. Henri

In a previous paper (Henri & Petrucci, hereafter paper I), we have derived a new model in order to explain the UV and X-ray emission of radio quiet AGNs. This model assumes that a point source of relativistic leptons (e+,e-) illuminates the accretion disk of the AGN by Inverse Compton process. This disk is supposed to be simply represented by a finite slab w

P. C. Frisch

An analysis of the distribution and kinematics of interstellar material within 500 pc of the Sun leads to the conclusion that the galactic environment of the Sun changes with time. Consideration of evidence for interstellar gas interacting with the solar wind implies that these variations may alter the interplanetary environment of the Earth. The events caus

V. G. Klochkova, V. E. Panchuk, E. L. Chentsov

In order to understand the evolutionary status of the anomalous supergiant UUHer, the prototype of the class of variable supergiants located at high galactic latitudes, we obtained several high-resolution spectra of this star, with the 6m telescope, over 5 years. This material was used for a search of possible temporal variations of the radial velocity at th

Kouichi Hirotani

We have studied non-stationary and non-axisymmetric perturbations of a magnetohydrodynamic accretion onto a rotating (Kerr) black hole. Assuming that the magnetic field dominates the plasma accretion, we find that the accretion suffers a large radial acceleration resulting from the Lorentz force, and becomes highly variable compared with the electromagnetic

Shihoko Ishii

Minimal model conjecture for a proper variety $X$ is that if $κ(X)\geq 0$, then $X$ has a minimal model with the abundance and if $κ=-\infty$, then $X$ is birationally equivalent to a variety $Y$ which has a fibration $Y \to Z$ with $-K_Y$ relatively ample. In this paper, we prove this conjecture for a $\D$-regular divisor on a proper toric variety by means

C. Adloff

Inclusive $K^0$ and $Λ$ photoproduction has been investigated at HERA with the H1 detector at an average photon-proton center of mass energy of 200 GeV in the transverse momentum range 0.5 <p_t <5 GeV. The production rates as a function of $p_t$ and center of mass rapidity are compared to those obtained in deep inelastic scattering at $\av{Q^2}=23 GeV^2$. A

William Arveson

A d-contraction is a d-tuple $(T_1,...,T_d)$ of mutually commuting operators acting on a common Hilbert space H such that $ \|T_1ξ_1+T_2ξ_2+... +T_dξ_d\|^2\leq \|ξ_1\|^2+\|ξ_2\|^2+...+\|ξ_d\|^2 $ for all $ξ_1,ξ_2,...,ξ_d\in H$. These are the higher dimensional counterparts of contractions. We show that many of the operator-theoretic aspects of function theor

J. Teschner

This paper has been withdrawn. A more satisfactory account of the results it was supposed to present will appear in a series of papers starting with hep-th/9712256 and hep-th/9712258

Preeti Parashar

A two-parametric non-standard (Jordanian) deformation of the Lie algebra $gl(2)$ is constructed, and then, exploited to obtain a new, triangular R-matrix solution of the coloured Yang-Baxter equation. The corresponding coloured quantum group is presented explicitly.

Jochen Schwiening

We have measured the differential cross sections for the production of $π^{\pm}, K^{\pm}, K^0, K^{*0}, Φ, p$ and $Λ$ in hadronic $Z^0$ decays and in subsets of flavor-tagged $Z^0 \to$ light quark ($u \bar{u}$, $d \bar{d}$, or $s \bar{s}$), $Z^0 \to c \bar{c}$ and $Z^0 \to b \bar{b}$ events. Charged hadrons were identified with the SLD Cherenkov ring imaging

Nathan Seiberg

We present four infinite series of new quantum theories with super-Poincare symmetry in six dimensions, which are not local quantum field theories. They have string like excitations but the string coupling is of order one. Compactifying these theories on $T^5$ we find a Matrix theory description of M theory on $T^5$ and on $T^5/\IZ_2$, which is well defined

Craig Pryor, M-E. Pistol, L. Samuelson

We calculate the electronic structure of nm scale InP islands embedded in $Ga_{0.51}In_{0.49}P$. The calculations are done in the envelope approximation and include the effects of strain, piezoelectric polarization, and mixing among 6 valence bands. The electrons are confined within the entire island, while the holes are confined to strain induced pockets. O

S. Gardner, H. B. O&#39;Connell, A. W. Thomas

The extraction of CKM-matrix-element information from hadronic B-decays generally suffers from discrete ambiguities, hampering the diagnosis of physics beyond the Standard Model. We show that a measurement of the rate asymmetry, which is CP-violating, in $B^{\pm}\toρ^{\pm}ρ^0(ω)\toρ^{\pm}π^+π^-$, where the invariant mass of the $π^+π^-$ pair is in the vicini

Andrzej Krasinski

This is the second part of a series of 3 papers. Using the same method and the same coordinates as in part 1, rotating dust solutions of Einstein&#39;s equations are investigated that possess 3-dimensional symmetry groups, under the assumption that only one of the Killing fields is spanned on the fields of velocity $u^α$ and rotation $w^α$, while the other t

Lars Brink, Alexander Turbiner, Niclas Wyllard

We propose to parametrize the configuration space of one-dimensional quantum systems of N identical particles by the elementary symmetric polynomials of bosonic and fermionic coordinates. It is shown that in this parametrization the Hamiltonians of the A_N, BC_N, B_N, C_N and D_N Calogero and Sutherland models, as well as their supersymmetric generalizations

A. Yu. Babansky, E. V. Gorbar, G. V. Shchepanyuk

Dynamical chiral symmetry breaking (D$χ$SB) is studied in the Nambu-Jona-Lasinio model for an arbitrary combination of external constant electric and magnetic fields. In 3+1 dimensions it is shown that the critical coupling constant increases with increasing of the value of the second invariant of electromagentic field $\vec{E}\cdot\vec{B}$, i.e. the second

E. Kh. Akhmedov

The present status of the neutrino magnetic moment solutions of the solar neutrino problem is summarized. After a brief review of the basics of the neutrino spin and spin-flavor precession I discuss the experimental data and show how the neutrino resonant spin-flavor precession (RSFP) mechanism can naturally account for sizeable time variations in the Homest

M. I. Antonoyiannakis, J. B. Pendry

Isolated dielectric spheres support resonant electromagnetic modes which are analogous to electronic orbitals and, like their electronic counterparts, can form bonding or anti-bonding interactions between neighbouring spheres. By irradiating the system with light at the bonding frequency an attractive interaction is induced between the spheres. We suggest th

Marek Czachor

A classical system violating the Bell inequality is discussed. The system is local, deterministic, observers have free will, and detectors are ideal so that no data are lost. The trick is based on two elements. First, a state of one observer is locally influenced by a &#34;particle&#34;. Second, random variables used in the experiment are complementary. A re

S. Mayburov

We argue that correct account of the quantum properties of macroscopic objects which form reference frames (RF) demand the change of the standard space-time picture accepted in Quantum Mechanics. The presence of RF free quantum motion in the form of wave packet smearing results in formal nonapplicability of Galilean or Lorentz space-time transformations in t

F. S. A. Cavalcante, M. S. Cunha, C. A. S. Almeida

In this work we consider an Abelian O(3) sigma model coupled nonminimally with a gauge field governed by a Maxwell and Chern-Simons terms. Bogomol'nyi equations are constructed for a specific form of the potential and generic nonminimal coupling constant. Furthermore, topological and nontopological self-dual soliton solutions are obtained for a critical valu

Koichi Yoshioka

We analyze finite supersymmetric SU(5) GUT taking into account the problem in the Higgs potential and threshold corrections to gauge and Yukawa couplings at GUT and SUSY scales which is important in case of large $\tan β$ model. We find that even with these finiteness conditions, which are very restrictive, there are parameter regions where low-energy experi

Kanehisa Takasaki

The author&#39;s recent results on an asymptotic description of the Schlesinger equation are generalized to the JMMS equation. As in the case of the Schlesinger equation, the JMMS equation is reformulated to include a small parameter $ε$. By the method of multiscale analysis, the isomonodromic problem is approximated by slow modulations of an isospectral pro

Tomohiro Matsuda

We examine a natural extension of D-term inflation and construct a successful model. General type of the D-term potential is shown to produce successful inflation with appropriate COBE normalization. The effect of the dilaton shift at the inflation period is taken into account.

Ashoke Sen

S-duality of hetertotic / type II string theory compactified on a six dimensional torus requires the existence of Kaluza-Klein dyons, carrying winding charge. We identify the zero modes of the Kaluza-Klein monopole solution which are responsible for these dyonic excitations, and show that we get the correct degeneracy of dyons as predicted by S-duality. The

Fritz Gesztesy, Rudi Weikard

An explicit characterization of all elliptic algebro-geometric solutions of the AKNS hierarchy is presented. Our approach is based on (an extension of) a classical theorem of Picard, which guarantees the existence of solutions which are elliptic of the second kind for n-th order ordinary differential equations with elliptic coefficients associated with a com

E. V. Ferapontov

The conserved densities of hydrodynamic type system in Riemann invariants satisfy a system of linear second order partial differential equations. For linear systems of this type Darboux introduced Laplace transformations, generalising the classical transformations in the scalar case. It is demonstrated that Laplace transformations can be pulled back to the t

Daniel Gottesman

Controlling operational errors and decoherence is one of the major challenges facing the field of quantum computation and other attempts to create specified many-particle entangled states. The field of quantum error correction has developed to meet this challenge. A group-theoretical structure and associated subclass of quantum codes, the stabilizer codes, h

S. N. Mayburov

The state vector evolution in the interaction of measured pure state with the collective quantum system or the field is analyzed in a nonperturbative QED formalism. As the model example the measurement of the electron final state scattered on nucleus or neutrino is considered. The produced electromagnetic bremsstrahlung contains the unrestricted number of so

I. Gelfand, V. Retakh

Our experience shows that dealing with noncommutative objects one should not imitate the classical commutative mathematics, but follow &#34;the way it is&#34; starting with basics. In this paper we consider mainly two such problems: noncommutative Plücker coordinates (as a background of a noncommutative geometry) and noncommutative Bezout and Vieta theorems

Andrew Kuprat, J. Tinka Gammel

We present an efficient method for anealing 3d metallic grains using Gradient Weighted Moving Finite Elements (GWMFE). The initial grain microstructure is generated from Monte-Carlo evolution of a an effective discrete model on the initial (frozen) unstructured grid generated for the external geometry of the GWMFE calculation.

Peter Filip, Jan Pisut

We point out that formation time of pions produced in heavy ion collisions modifies the mass spectrum of dileptons produced via pipi -> ee annihilation. Increasing formation time enhances the production of dileptons with lower masses. The effect offers an explanation of a part of the enhanced production of dileptons below the rho-meson mass as observed by th

A. Dote, H. Horiuchi, Y. Kanada-En&#39;yo

In order to study light unstable nuclei systematically, we propose a new method &#39;&#39;AMD + Hartree-Fock&#39;&#39;. This method introduces the concept of the single particle orbits into the usual AMD. Applying AMD + HF to Be isotopes, it is found that the calculated lowest intrinsic states with plus and minus parities have rather good correspondence with

F. Hofmann, H. Lenske

The density matrix expansion is used to derive a local energy density functional for finite range interactions with a realistic meson exchange structure. Exchange contributions are treated in a local momentum approximation. A generalized Slater approximation is used for the density matrix where an effective local Fermi momentum is chosen such that the next t

Su Houng Lee

We formulate a QCD sum rule to find the three momentum dependence of the peak position of the vector meson spectral density in nuclear medium. We find less than 2 % (0.1 %) shift of the peak position at nuclear matter density and at ($q =0.5$GeV/c) for the $ρ,ω(ϕ$) mesons. However, at higher density and three momentum, its effect becomes non-negligible. The

A. K. Chaudhuri

We have analysed the direct photon data obtained by the WA80 collaboration in 200 A GeV S+Au collision at CERN SPS, in a one dimensional hydrodynamical model. Two scenario was considered: (i) formation of quark-gluon plasma and (ii) formation of hot hadronic gas. For both the scenario, ideal as well as extremely viscous fluid was considered. It was found tha

Vyacheslav S. Krushkal, Peter Teichner

We prove a geometric refinement of Alexander duality for certain 2-complexes, the so-called gropes, embedded into 4-space. This refinement can be roughly formulated as saying that 4-dimensional Alexander duality preserves the disjoint Dwyer filtration. In addition, we give new proofs and extended versions of two lemmas of Freedman and Lin which are of centra

Sarah Rees

The existing algorithm to compute and verify the automata associated with an automatic group deals only with the subclass of shortlex automatic groups. This paper describes the extension of the algorithm to deal with automatic groups associated with other word orders (the algorithm has now been implemented ) and reports on the use of the algorithm for specif

Sarah Rees

A group is combable if it can be represented by a language of words satisfying a fellow traveller property; an automatic group has a synchronous combing which is a regular language. This paper gives a systematic analysis of the properties of groups with combings in various formal language classes, and of the closure properties of the associated classes of gr

Mary K. Gaillard, Bruno Zumino

We discuss duality invariant interactions between electromagnetic fields and matter. The case of scalar fields is treated in some detail.

Bernard de Wit, Kasper Peeters, Jan Plefka

We study supermembranes in the light-cone gauge in eleven flat dimensions with compact directions. The membrane states are subject to only the central charges associated with closed two-branes, which, in this case, are generated by the winding itself. We present arguments why this winding leaves the mass spectrum continuous. The lower bound on the mass spect

D. Bazeia, J. R. S. Nascimento, R. F. Ribeiro, D. Toledo

In this paper we consider a class of systems of two coupled real scalar fields in bidimensional spacetime, with the main motivation of studying classical or linear stability of soliton solutions. Firstly, we present the class of systems and comment on the topological profile of soliton solutions one can find from the first-order equations that solve the equa

R. B. Mann

I examine the pair creation of black holes in spacetimes with a cosmological constant of either sign. I consider cosmological C-metrics and show that the conical singularities in this metric vanish only for three distinct classes of black hole metric, two of which have compact event horizons on each spatial slice. One class is a generalization of the Reissne

R. Pelka

Backreaction of excitations on a planar domain wall in a real scalar field model is investigated in the cases of homogeneous, plane wave and wave packet type excitations. It is found that the excited domain wall radiates. The method of calculating backreaction for the general forms of excitations is also presented.

Kentaro Hori, Hirosi Ooguri, Cumrun Vafa

We show how Higgs mechanism for non-abelian N=2 gauge theories in four dimensions is geometrically realized in the context of type II strings as transitions among compactifications of Calabi-Yau threefolds. We use this result and T-duality of a further compacitification on a circle to derive N=4, d=3 dual field theories. This reduces dualities for N=4 gauge

Andreas Aste, Michael D&#34;utsch, G&#34;unter Scharf

We show how the widely used concept of spontaneous symmetry breaking can be explained in causal perturbation theory by introducing a perturbative version of quantum gauge invariance. Perturbative gauge invariance, formulated exclusively by means of asymptotic fields, is discussed for the simple example of Abelian U(1) gauge theory (Abelian Higgs model). Our

Avinash Dhar

We discuss further a recent space-time interpretation of the $c=1$ matrix model which retains both sides of the inverted harmonic oscillator potential in the underlying free fermion theory and reproduces the physics of the discrete state moduli of two-dimensional string theory. We show that within this framework the linear tachyon background in flat space ar

Y. M. Cho, Kyoungtae Kimm

We present finite energy analytic monopole and dyon solutions whose size is fixed by the electroweak scale. Our result shows that genuine electroweak monopole and dyon could exist whose mass scale is much smaller than the grand unification scale.

Harold Steinacker

Quantum groups in general and the quantum Anti-de Sitter group $U_q(so(2,3))$ in particular are studied from the point of view of quantum field theory. We show that if $q$ is a suitable root of unity, there exist finite-dimensional, unitary representations corresponding to essentially all the classical one-particle representations with (half)integer spin, wi

J. J. M. Verbaarschot

Recently, QCD Dirac spectra have been obtained for reasonably large lattices. We argue that correlations of these spectra are universal and can be obtained from a random matrix model with the global symmetries of QCD. Analytical arguments are presented to support this claim. Detailed comparisons with lattice results are made. We analyze spectral correlations

W. Buchmuller, A. Jakovac

We study the retarded response function in scalar $ϕ^4$-theory at finite temperature. We find that in the high-temperature limit the imaginary part of the self-energy is given by the classical theory to leading order in the coupling. In particular the plasmon damping rate is a purely classical effect to leading order, as shown by Aarts and Smit. The dominant

A. Donini, F. Feruglio, J. Matias, F. Zwirner

We consider an extension of the standard electroweak theory with gauge group $SU(2)_L \times SU(2)_R \times U(1)_{\tilde{Y}}$, where the gauge bosons of the extra $SU(2)_R$ factor do not couple to ordinary fermions. We show that precision electroweak data and flavour physics provide quite stringent indirect constraints on its parameter space, but still allow

S. Groote, J. G. Körner, O. I. Yakovlev

We consider diagonal and non-diagonal QCD sum rules for the ground state heavy baryons to leading order in $1/m_Q$ and at next-to-leading order in $α_S$. In the non-diagonal case we evaluate the eight different two-loop diagrams which determine the perturbative $α_S$-corrections to the Wilson coefficient of the quark condensate in the Operator Product Expans

J. P. Ma

By expanding functions of parton fragmentation into a heavy hadron in the inverse of the heavy quark mass $m_Q$ we attempt to factorize them into perturbative- and nonperturbative parts. In our approach the nonperturbative parts can be defined as matrix elements in heavy quark effective theory, the shape of the functions is predicted by perturbative QCD. In

J. P. Ma

We analyze higher twist effect in photoproduction of quarkonium, where the quarkonium is a spin-triplet, S-wave state. We find that the nonperturbative effect of next-to-leading twist is contained in three correlation functions related to the initial hadron and some of the effect of next-to-leading twist is only suppressed by the inverse of the mass square o

J. P. Ma, B. H. J. McKellar

We use improved lattice actions for glue, light quarks and heavy quarks for which we use lattice NRQCD to compute hadron masses. Our results are in good agreement with experiment, except for charmed hadrons. It seems that charmed quar ks are not well approximated as heavy quarks nor as light quarks.