May 1994 arXiv papers — page 4

Benjamin Grinstein

The form factors of the flavor changing vector current between a $\bar q Q$-meson and the lightest $\bar q q$ (pseudoscalar-)meson are computed exactly and explicitly in the 't~Hooft model (planar QCD in $1+1$ dimensions) in the limit that the mass of $q$-quark vanishes.

Jean-Loup Gervais, Jens Schnittger

We construct the exponentials of the Liouville field with continuous powers within the operator approach. Their chiral decomposition is realized using the explicit Coulomb-gas operators we introduced earlier. {}From the quantum-group viewpoint, they are related to semi-infinite highest or lowest weight representations with continuous spins. The Liouville fie

O. Steinmann

It is shown that the perturbative expansions of the correlation functions of a relativistic quantum field theory at finite temperature are uniquely determined by the equations of motion and standard axiomatic requirements, including the KMS condition. An explicit expression as a sum over generalized Feynman graphs is derived. The canonical formalism is not u

O. Moritsch, M. Schweda

The BRST transformations for gravity with torsion including Weyl symmetry are discussed by using the so-called Maurer-Cartan horizontality conditions. Also the coupling of scalar matter fields to gravity is incorporated in this analysis. With the help of an operator $\d$ which allows to decompose the exterior space-time derivative as a BRST commutator we sol

S. N. Solodukhin

The 2D gravity described by the action which is an arbitrary function of the scalar curvature $f(R)$ is considered. The classical vacuum solutions are analyzed. The one-loop renormalizability is studied. For the function $f=R \ln R$ the model coupled with scalar (conformal) matter is exactly integrated and is shown to describe a black hole of the 2D dilaton

Ken-ji Hamada, Hiroshi Ishikawa

We investigate the Ward identities of the $\W_{\infty}$ symmetry in the super-Liouville theory coupled to the super-conformal matter of central charge ${\hat c}_M = 1-2(p-q)^2 /pq$. The theory is classified into two chiralities. For the positive chirality, all gravitationally dressed scaling operators are generated from the $q-1$ gravitational primaries by a

Jeroen Snippe

We construct all instantons for the \nlsig\ on a cylinder, known not to exist on a finite time interval. We show that the widest instantons go through sphalerons. A re-interpretation of moduli-space transforms the scale parameter $ρ$ to a boundary condition in time. This may give a handle on the $ρ\rightarrow0$ divergent instanton gas.

Isard Dunietz, Peter S. Cooper, Adam F. Falk, Mark B. Wise

It is usually assumed that the production of baryons in $B$ meson decays is induced primarily by the quark level process $b\to c\bar ud$, where the charm quark hadronizes into a charmed baryon. With this assumption, the $Λ_c$ momentum spectrum would indicate that the transition $B\toΛ_c X$ is dominated by multi-body $B$ decays. However, a closer examination

C. E. Carlson, J. Milana

Applying perturbative QCD methods recently seen to give a good description of the two body hadronic decays of the B meson, we address the question of bound-state effects on the decay B into K* + gamma. Consistent with most analyses, we demonstrate that gluonic penguins, with photonic bremsstrahlung off a quark, change the decay rate by only a few percent. Ho

J. Bolz, R. Jakob, P. Kroll, M. Bergmann

The behavior of the proton magnetic form factor is studied within the modified hard scattering picture, which takes into account gluonic radiative corrections in terms of transverse separations. We parallel the analysis given previously by Li and make apparent a number of serious objections. The appropriate cut-off needed to render the form-factor calculatio

M. Bjornberg, K. Dannbom, D. O. Riska

We derive the anharmonic correction to the hyperon energy in the bound state version of the topological soliton model for the hyperons, and show that it represents a negative correction of at most 10% to the energy of the bound heavy flavour two-meson system in the case of cascade hyperons. The main anharmonic correction arises from the mass term in the Lagr

A. Capella, A. Kaidalov, C. Merino, J. Tran Thanh Van

In the framework of conventional Regge theory we present a common description of total photon-proton cross-section and proton structure functions in the region $0 \leq Q^2 \leq 5 \ {\rm GeV}^2$. Using it as an initial condition in the perturbative QCD evolution equation, we describe structure functions at any $Q^2$ and $x$ - including the small $x$ region ex

K. Kumekawa, T. Moroi, T. Yanagida

We show that a very flat potential of inflaton required for a sufficient inflation is naturally obtained in $N=1$ supergravity by imposing a discrete $R$-invariance $Z_{n}$. Several cosmological constraints on parameters in the inflaton superpotential are derived. The reheating temperature turns out to be $(1-10^8)$GeV for the cases of $n$=3--10. Baryogenesi

J. Ignatius, K. Kajantie, H. Kurki-Suonio, M. Laine

We examine the first-order cosmological QCD phase transition for a large class of parameter values, previously considered unlikely. We find that the hadron bubbles can nucleate at very large distance scales, they can grow as detonations as well as deflagrations, and that the phase transition may be completed without reheating to the critical temperature. For

SLD Collaboration

In the 1993 SLC/SLD run, the SLD recorded 50,000 $\z0$ events produced by the collision of longitudinally polarized electrons on unpolarized positrons at a center-of-mass energy of 91.26 GeV. The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)\%. We measure the left-right cross-section asymmetry in $\z0$ boson production,

A. Gabutti

The propagation of the excess of quasiparticles and phonons produced by a nuclear recoil inside Sn and Zn superheated superconducting granules will be discussed. The decay towards equilibrium of the initial disturbance is assumed to be a thermal diffusion process described by a set of coupled heat flow equations for the effective quasiparticle and phonon tem

K. Schmiemann

The time difference between a particle interaction in a Superheated Superconducting Granule (SSG) and the resulting phase transition signal has been explored. Detectors containing Zn and Sn SSG were irradiated with neutrons and protons to study the heating mechanism taking place in nuclear recoil and ionizing events. Scattered neutrons have been detected by

S. Carlip

General relativity in three spacetime dimensions is used to explore three approaches to the ``problem of time'' in quantum gravity: the internal Schrödinger approach with mean extrinsic curvature as a time variable, the Wheeler-DeWitt equation, and covariant canonical quantization with ``evolving constants of motion.'' (To appear in {\em Proc

Yoav Peleg

Using canonical (Schrodinger) quantization of spherically symetric gravitational dust systems, we find the quasi-classical (coherent) state, |α^{(s)}>, that corresponds to the classical Schwarzschild solution. We calculate the ``quasi-classical Schwarzschild mertic", which is the expectation value of the quantized metric in thhis quasi-classical state. D

B. R. Trees

We report evidence of a superconducting instability (of $T_{1g}$ symmetry) in the infinite-U Anderson lattice in the presence of crystal fields of cubic symmetry. We assume a lattice of $4f$ sites, each with a total angular momentum of $J=5/2$ that is split by crystal fields into a low-lying doublet of $Γ_7$ symmetry and an excited quartet of $Γ_8$ symmetry.

Ian Affleck, Andreas W. W. Ludwig

The boundary conformal field theory approach to quantum impurity problems is used to study the Fermi edge singularity, occuring in the X-ray adsorption probablility. The deep-hole creation operator, in the effective low-energy theory, changes the boundary condition on the conduction electrons. By a conformal mapping, the dimension of such an operator is rela

Anthony Chan, A. H. MacDonald

The competition between liquid and solid states of strongly correlated electron systems occurs in a novel way in a strong magnetic field. The fact that certain Landau level filling factors are especially favorable for the formation of strongly correlated liquid states, gives rise to the fractional quantum Hall effect. In this article we discuss some conseque

K Nikolić, A MacKinnon

In this paper we present and discuss our results for the conductance and conductance fluctuations of narrow quantum wires with two types of disorder: boundary roughness (hard wall confining potential) and islands of strongly scattering impurities within the bulk of the wire. We use a tight--binding Hamiltonian to describe the quantum wire, infinite perfect l

Raymond Fresard

A new formulation for the study of interacting bosons on a lattice is introduced. This approach is used to give analytical expressions for the Mott insulating lobes in the phase diagram and to calculate the density-density correlation function. It is also shown that, at mean-field level, this newly introduced slave boson theory coincides with mean-field theo

George B. Rybicki, William H. Press

With the ansatz that a data set's correlation matrix has a certain parametrized form (one general enough, however, to allow the arbitrary specification of a slowly-varying decorrelation distance and population variance) the general machinery of Wiener or optimal filtering can be reduced from $O(n^3)$ to $O(n)$ operations, where $n$ is the size of the dat

A. Crisanti, M. Falcioni, G. Paladin, A. Vulpiani

We propose a mechanism which produces periodic variations of the degree of predictability in dynamical systems. It is shown that even in the absence of noise when the control parameter changes periodically in time, below and above the threshold for the onset of chaos, stochastic resonance effects appears. As a result one has an alternation of chaotic and reg

Garrelt Mellema

Using a radiation-gasdynamics code the evolution of spherical planetary nebulae is followed, while taking into account the evolution of central star and the fast wind. These models show the importance of ionization fronts for the structure of planetary nebulae, especially for the so called multiple shell nebulae (MSPNe). It is shown that the outer shell is f

Joseph Lipman

The adjoint of an ideal I in a regular local ring R is the R-ideal adj(I):=H^0(Y, Iω_Y), where f:Y -> Spec(R) is a proper birational map with Y nonsingular and IO_Y invertible, and ω_f is a canonical relative dualizing sheaf. (Such an f is supposed to exist.) The basic conjecture is that I.adj(I^n)=adj(I^{n+1}) whenever n is >= the analytic spread of I. This

Oliver Küchle

Let $X$ be a Fano manifold which is the zero scheme of a general global section $s$ in an irreducible homogenous vector bundle over a Grassmannian. We prove that the restriction of the Plücker embedding embeds $X$ projectively normal, and that every small deformation of $X$ comes from a deformation of the section $s$. These results are strengthened in the ca

H. Leutwyler

The magnitude of $m_u,\,m_d$ and $m_s$ is discussed on the basis of Chiral Perturbation Theory. In particular, the claim that $m_u=0$ leads to a coherent picture for the low energy structure of QCD is examined in detail. It is pointed out that this picture leads to violent flavour asymmetries in the matrix elements of the scalar and pseudoscalar operators, w

V. S. Fadin, R. Fiore, A. Quartarolo

The quark loop contribution to the reggeon-reggeon-gluon vertex is calculated in QCD, where the reggeon is the reggeized gluon. Compared with the vertex in the Born approximation, this contribution exhibits a new spin structure as well as the gluon loop one. A remarkable but not complete cancellation between gluon and quark contributions to this new spin str

E. Buffenoir Ph. Roche

In this article we analyze a two dimensional lattice gauge theory based on a quantum group.The algebra generated by gauge fields is the lattice algebra introduced recently by A.Yu.Alekseev,H.Grosse and V.Schomerus we define and study wilson loops and compute explicitely the partition function on any Riemann surface. This theory appears to be related to Chern

M. J. Duff, G. W. Gibbons, P. K. Townsend

It is known that, in string sigma-model metric, the `extreme' fivebrane solution of D=10 supergravity interpolates between D=10 Minkowski spacetime and a supersymmetric $S^3$ compactification to a linear dilaton vacuum. We show here that, in {\it fivebrane} sigma-model metric, the extreme string solution of D=10 supergravity interpolates between Minkowsk

Masaki Murata, Makoto Nagao

When translating Japanese nouns into English, we face the problem of articles and numbers which the Japanese language does not have, but which are necessary for the English composition. To solve this difficult problem we classified the referential property and the number of nouns into three types respectively. This paper shows that the referential property a

A. Kazarnovski-Krol

Value of generalized hypergeometric function at a special point is calculated. More precisely, value of certain multiple integral over vanishing cycle (all arguments collapse to unity) is calculated. The answer is expressed in terms of $Γ$-functions. The constant is relevant to the part of $ρ$ in the Gindikin-Karpelevich formula for c-function of Harish-Chan

Levan R. Surguladze

The results of analytical evaluation of $O(α_s^2)$ QCD contributions due to the nonvanishing quark masses to $Γ_{H\rightarrow q_f\overline{q}_f}$ are presented. The ``triangle anomaly'' type contributions are included. As a byproduct the $O(α_s^3)$ logarithmic contributions are evaluated. The results are presented both in terms of running and pole qu

P Navratil, H B Geyer, J Dobaczewski

We demonstrate that exact supersymmetry can emerge in a purely fermionic system. This "supersymmetry without bosons" is unveiled by constructing a novel boson-fermion Dyson mapping from a fermion space to a space comprised of collective bosons and ideal fermions. In a nuclear structure context the collective spectra of even and odd nuclei can then be

G. Mussardo

The non-perturbative mapping between different Quantum Field Theories and other features of two-dimensional massive integrable models are discussed by using the Form Factor approach. The computation of ultraviolet data associated to the massive regime is illustrated by taking as an example the scattering theory of the Ising Model with boundary.

T. D. Palev, N. I. Stoilova

The properties of the three-dimensional noncanonical osp(3/2) oscillators, introduced in J.Phys. A: Math. Gen. {\bf 27} (1994) 977, are further studied. The angular momentum M of the oscillators can take at most three values M=p-1,p,p+1, which are either all integers or all half-integers. The coordinates anticommute with each other. Depending on the state sp

Stefan K. Kehrein, Franz Wegner

In a recent publication we have investigated the spectrum of anomalous dimensions for arbitrary composite operators in the critical N-vector model in 4-epsilon dimensions. We could establish properties like upper and lower bounds for the anomalous dimensions in one-loop order. In this paper we extend these results and explicitly derive parts of the one-loop

I. Balitsky

I discuss the possible instanton-induced multiparticle production in hard processes in QCD Figures are available upon request

G. Amelino-Camelia, F. Buccella, L. Rosa

We study the predictions for Majorana masses for neutrinos in SO(10) grandunification models. (This paper precedes and is cited in the article "PROTON DECAY AND NEUTRINO MASSES IN SO(10)", hep-ph/9405332)

I. Dymnikova, M. Krawczyk

First postinflationary stage of the Universe evolution is considered in more detail. It is shown that heavy particles with mass $M_{H}\sim M_{GUT}$ arising at the Universe at phase transitions at Grand Unification Energies behave like ideal quantum degenerate Bose gas. The equation of state for both scalar and gauge bosons is presented including the coupling

F. Acampora, G. Amelino-Camelia, F. Buccella, O. Pisanti

In the last few years physicists have been looking at $SO(10)$ GUT models with renewed attention because it has been realized that the SU(5) minimal model cannot unify the strong, electromagnetic and weak interactions in a way consistent with the experimental values of $α(M_Z)$, $\si$ and $α_S(M_Z)$. In this paper we derive lower limits on neutrino masses, r

Xuemin Jin, Marina Nielsen

Within finite-density QCD sum-rule approach we investigate the self-energies of $Σ$ hyperons propagating in nuclear matter from a correlator of $Σ$ interpolating fields evaluated in the nuclear matter ground state. We find that the Lorentz vector self-energy of the $Σ$ is similar to the nucleon vector self-energy. The magnitude of Lorentz scalar self-energy

Ernest Ma

The existence of an SU(3) X SU(2)_L X SU(2)_R X U(1) gauge symmetry with g_L = g_R at the TeV energy scale is shown to be consistent with supersymmetric SO(10) grand unification at around 1O^{16} GeV if certain new particles are assumed. The additional imposition of a discrete Z_2 symmetry leads to a generalized definition of R parity as well as highly suppr

V. A. Khoze

I will discuss, in a concise way, the main objectives of QCD studies at LEP 2.

Tadashi Kon, Toshihiko Nonaka

We propose a mechanism which could explain a slight excess of top signal rate recently reported by CDF in the framework of the supersymmetric standard model. If the scalar partner of the top (stop) is sufficiently light, the gluino with an appropriate mass could decay into the stop plus the top with almost 100\% branching ratio and experimental signatures of

Harry J. Lipkin

The use of weak decays to determine proton spin structure is examined in view of possible violations of the Bjorken and Gottfried Sum rules, flavor symmetry breaking and flavor asymmetry in the sea. The use of the neutron decay is found to be unaffected by all these. A method for including these effects in analyses of hyperon decays shows that a flavor-asymm

Valeri Frolov, Erik A. Martinez

We present the gravitational action and Hamiltonian for a spatially bounded region of an eternal black hole. The Hamiltonian is of the general form $H=H_{+} - H_{-}$, where $H_{+}$ and $H_{-}$ are respectively the Hamiltonians for the regions $M_+$ and $M_-$ located in the left and right wedges of the spacetime. We construct explicitly the quasilocal energy

Lee-Wen Chen, M. Cristina Marchetti

We use a hydrodynamics theory to discuss the response of a viscous flux-line liquid to an ac perturbation applied at the surface of the sample. The theory incorporates viscoelastic effects and describes the crossover between liquid-like and solid-like response of the vortex array as the frequency of the perturbation increases. A large viscosity from flux-lin

G. Tormen, D. Burstein

The H magnitude aperture data published by the Aaronson et al. collaboration over a 10-year period is collected into a homogeneous data set of 1731 observations of 665 galaxies. 96\% of these galaxies have isophotal diameters and axial ratios determined by the Third Reference Catalogue of Bright Galaxies (de Vaucouleurs et al. 1991), the most self-consistent

Edward J. M. Colbert, Andrew S. Wilson, Jonathan Bland-Hawthorn

We present new radio observations of the ``prototypical'' ultra-luminous far- infrared galaxy NGC~6240, obtained using the VLA at 20~cm in `B' configuration and at 3.6~cm in `A' configuration. These data, along with those from four previous VLA observations, are used to perform a comprehensive study of the radio emission from NGC~6240. Approx

Katherine Freese

We find a coupling of Pseudo Nambu Goldstone bosons (PNGBs) to other (ordinary) scalars, and consider its importance in various contexts. Our original motivation was the model of Double Field inflation [1]. We also briefly consider the role of this coupling for the case of the QCD axion.

Yun Wang

We study a simple extension of Linde's hybrid inflation model, with the inflaton mass term replaced by the most general renormalizable potential for $ϕ$. The unprocessed power spectrum of density perturbations can have two minima and one maximum, roughly corresponding to two steep regions separated by a somewhat flat region in $V(ϕ)$. In the examples stu

E. Frenkel, V. Kac, A. Radul, W. Wang

We study representations of the central extension of the Lie algebra of differential operators on the circle, the W-infinity algebra. We obtain complete and specialized character formulas for a large class of representations, which we call primitive; these include all quasi-finite irreducible unitary representations. We show that any primitive representation

J. G. Russo

We study the thermal ensemble of a gas of free strings in presence of a magnetic field. We find that the thermodynamical partition function diverges when the magnetic field exceeds some critical value $B_{\rm cr}$, which depends on the temperature. We argue that there is a first-order phase transition with a large latent heat. At the critical value an infini

Boris Khesin, Feodor Malikov

We construct affinization of the algebra $gl_λ$ of ``complex size'' matrices, that contains the algebras $\hat{gl_n}$ for integral values of the parameter. The Drinfeld--Sokolov Hamiltonian reduction of the algebra $\hat{gl_λ}$ results in the quadratic Gelfand--Dickey structure on the Poisson--Lie group of all pseudodifferential operators of fraction

R. D. Ball, S. Forte

Perturbative QCD predicts that at sufficiently large $Q^2$ and small $x$ nucleon structure functions should exhibit scaling in the two variables $\sqrt{\ln\smallfrac{1}{x}\ln\ln Q^2}$ and $\sqrt{\ln\smallfrac{1}{x}\big/\ln\ln Q^2}$, provided only that the small-$x$ behaviour of the input to the perturbative QCD evolution is sufficiently soft. We derive these

Bo-Qiang Ma, Andreas Schaefer, Walter Greiner

We analyse the proton-induced Drell-Yan production in both the flavor asymmetry and isospin breaking explanations for the violation of the Gottfried sum rule. Consequences from three different forms of corrections to the flavor and isospin symmetric parton distributions are examined. It is found that the calculated results are sensitive to the choices of par

D. Giulini, C. Kiefer

We investigate the class of ultralocal metrics on the configuration space of canonical gravity. It is described by a parameter $α$, where $α=0.5$ corresponds to general relativity. For $α$ less than a critical value the signature is positive definite, while for all other values it is indefinite. We show that in the positive definite case gravity becomes repu

I. A. Bandos, A. A. Zheltukhin

Unique twistor--like Lorentz harmonic formulation for all N=1 supersymmetric extended objects (super-p-branes) moving in the space--time of arbitrary dimension D (admissible for given $p$) are suggested. The equations of motion are derived, explicit form of the κ-symmetry transformations is presented and the classical equivalence to the standard formulation

Riccardo Rattazzi, Uri Sarid, Lawrence J. Hall

We analyze some consequences of grand unification of the third-generation Yukawa couplings, in the context of the minimal supersymmetric standard model. We address two issues: the prediction of the top quark mass, and the generation of the top-bottom mass hierarchy through a hierarchy of Higgs vacuum expectation values. The top mass is strongly dependent on

Moshe Gai

After reviewing some of the basic concepts, nomenclatures and parametrizations of Astronomy, Astrophysics and Cosmology, we introduce a few central problems in Nuclear Astrophysics, including the hot-CNO cycle, helium burning in massive stars, and solar neutrino's. We demonstarte that SECONDARY (RADIOACTIVE) NUCLEAR BEAMS allow for considerable progress

Jorge L. Lopez, D. V. Nanopoulos, Kajia Yuan

We study the problem of identifying the moduli fields in fermionic four-dimensional string models. We deform a free-fermionic model by introducing exactly marginal operators in the form of Abelian Thirring interactions on the world-sheet, and show that their couplings correspond to the untwisted moduli fields. We study the consequences of this method for sim

D. Cangemi, R. Jackiw

We show that string-inspired lineal gravity interacting with matter fields cannot be Dirac-quantized owing to the well known anomaly in energy-momentum tensor commutators.

J. G. Russo, L. Susskind

We calculate the density of states with given mass and spin in string theory and obtain asymptotic formulas. We also compute the tree-level gyromagnetic couplings for arbitrary physical states in the heterotic string theory. These results are then applied to study whether fundamental strings can consistently describe the microphysics of the black hole horizo

G. A. T. F. da Costa, L. O'Raifeartaigh

By reducing a split $G_2$ Kac-Moody algebra by a non-maximal set of first-class constraints we produce W-algebras which (i) contain fields of negative conformal spin and (ii) are not trivial extensions of canonical W-algebras.

G. N. Stratopoulos, T. N. Tomaras

A non-relativistic scalar field coupled minimally to electromagnetism supports in the presence of a homogeneous background electric charge density the existence of smooth, finite-energy topologically stable flux vortices. The static properties of such vortices are studied numerically in the context of a two parameter model describing this system as a special

J. Alfaro, P. H. Damgaard

We discuss the geometry of the Lagrangian quantization scheme based on (generalized) Schwinger-Dyson BRST symmetries. When a certain set of ghost fields are integrated out of the path integral, we recover the Batalin-Vilkovisky formalism, now extended to arbitrary functional measures for the classical fields. Keeping the ghosts reveals the crucial role playe

T. H. Hansson, H. B. Nielsen, I. Zahed

We study two-dimensional QED with unequal charges at finite temperature, and show that there is a phase with a spontaneously broken $Z_n$ symmetry. In spite of this, we were not able to establish the presence of domain walls. The relevance for QCD in higher dimensions is discussed.

Ehab Malkawi, C. --P Yuan

We propose to probe the electroweak symmetry breaking sector by measuring the effective couplings of the top quark to gauge bosons. Using precision LEP data, we constrain the non--universal couplings of t-t-Z and t-b-W, parameterized by $κ_{L}^{NC}$, $κ_{R}^{NC}$, $κ_{L}^{CC}$ and $κ_{R}^{CC}$, in the electroweak chiral lagrangian framework. Different scenar

L. Clavelli

We investigate correlations among various parameters in the solution space of minimal supersymmetric grand unification. In particular the extent to which the top quark Yukawa coupling exhibits fixed point behavior is discussed and we compare various analytic approximations to its value at the top mass with its exact value in numerical solutions.\\ $^*$ Talk

J. R. Espinosa

We study the possibility of relaxing the cosmological bound on the Higgs mass coming from the requirement of non-erasure of the baryon asymmetry by sphalerons. After reviewing the Standard Model case we obtain this bound in two extensions of it: 1) The Standard Model with an additional gauge singlet, and 2) The Minimal Supersymmetric Standard Model. Taking f

M. Gourdin, A. N. Kamal, X. Y. Pham

We establish restrictions on $B \ra K ( K^* )$ form factors imposed by recent data on $B \ra J/Ψ+ K ( K^* ) $ decay rates and polarization. We show that these constraints are not satisfied by few commonly used models. Finally, we relate $B \ra K ( K^* )$ form factors to those in $D \ra K ( K^* )$ transitions using the heavy flavour symmetry as proposed by Is

Bernd A. Kniehl

We review the status of radiative corrections to the decay rates of the Standard-Model Higgs boson in the mass range accessible at LEP~2. Specifically, we consider corrections of ${\cal O}(α)$, ${\cal O}(α_sG_Fm_t^2)$, and ${\cal O}(G_F^2M_H^4)$ to the fermionic decay rates and two-loop QCD corrections to the hadronic decay rates.

Kari Enqvist, Poul Olesen

We address the question of the existence of magnetic domains in a recent scenario for the creation of primordial magnetic fields. We write down the magnetohydrodynamic equation in an expanding universe in the infinite conductivity limit and discuss its solution. No domains are found.

Kari Enqvist

A primordial magnetic field could be responsible for the observed magnetic fields of the galaxies. One possibility is that such a primordial field is generated at the electroweak phase transition because of the fluctuations in the Higgs field gradients. I describe a statistical averaging procedure which gives rise to a field of a correct magnitude. Another p

F. E. Close, A. Wambach

Recently we have shown that due account of Wigner spin rotations is needed to match the ISGW model consistently onto HQET. We now discuss the flavour dependence of this procedure. We find that for finite mass ``heavy'' quark the universal function $ξ(y=1) \approx 1$ but the slope is proportional to the energy of the spectator quarks, and ratios of fo

C. G. Arroyo

We report a precise measurement of the weak mixing angle from the ratio of neutral current to charged current inclusive cross-sections in deep-inelastic neutrino-nucleon scattering. The data were gathered at the CCFR neutrino detector in the Fermilab quadrupole-triplet neutrino beam, with neutrino energies up to 600 GeV. Using the on-shell definition, ${\rm

I. M. Dremin, V. Arena, G. Boca, G. Gianini

The ratio of cumulant to factorial moments of experimental multiplicity distributions has been calculated for $e^{+}e^{-}$ and $hh$ interactions in a wide range of energies. As a function of the rank it exhibits an initial steep decrease and a series of oscillations around zero. Those features cannot be reproduced by the Negative Binomial Distribution. A com

C. Kiefer

I give a brief review of the recovery of semiclassical time from quantum gravity and discuss possible extrapolations of this concept to the full theory.

M. C. Bento, O. Bertolami

We establish the main features of homogeneous and isotropic dilaton, metric and Yang-Mills field configurations in a cosmological framework. Special attention is paid to the energy exchange between the dilaton and the Yang-Mills field and, in particular, a new energy exchange term is identified. Implications for the Polonyi problem in 4-dimensional string mo

S. C. Power

A new homology is defined for a non-self-adjoint operator algebra and distinguished masa which is based upon cycles and boundaries associated with complexes of partial isometries in the stable algebra. Under natural hypotheses the zeroth order group coincides with the $\ K_0$\ group of the generated C*-algebra. Several identifications and applications are gi

S. C. Power

A stable homology theory is defined for completely distributive CSL algebras in terms of the point-neighbourhood homology of the partially ordered set of meet-irreducible elements of the invariant projection lattice. This specialises to the simplicial homology of the underlying simplicial complex in the case of a digraph algebra. These groups are computable

Jian Ma, C. Quitmann, R. J. Kelley, P. Alméras

We have performed high energy resolution angle-resolved photoemission studies of the normal state band structure of oxygen overdoped $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$. We find that there is an extended saddle point singularity in the density of states along $Γ-\bar{M}-Z$ direction. The data also indicate that there is an asymmetry in the Fermi surface for bo

Shiyi Chen, Turab Lookman

The hydrodynamic effects on the late stage kinetics in spinodal decomposition of multicomponent fluids are examined using a lattice Boltzmann scheme with stochastic fluctuations in the fluid and at the interface. In two dimensions, the three and four component immiscible fluid mixture (with a $1024^2$ lattice) behaves like an off-critical binary fluid with a

K. -W. Ng, A. D. Speliotopoulos

The evolution of scale-invariant gravity waves from the early universe is analyzed using an equation of state which smoothly interpolates between the radiation dominated era and the present matter dominated era. We find that for large wavenumbers the standard scale-invarant wavefunction for the gravity wave severely {\it underestimates\/} the actual size of

H. J. Haubold, A. M. Mathai

The study of solar neutrinos may provide important insights into the physics of the central region of the Sun. Four solar neutrino experiments have confirmed the solar neutrino problem but do not clearly indicate whether solar physics, nuclear physics, or neutrino physics have to be improved to solve it. Nonlinear relations among the different neutrino fluxe

Max Tegmark, Joseph Silk

We generalize previous work on early photoionization to CDM models with Omega<1. Such models have received recent interest because the excess power in the large-scale galaxy distribution is phenomenologically fit if the ``shape parameter&#34; Gamma=h Omega_0 is about 0.25. It has been argued that such models may require early reionization to suppress small-s

D. L. Cox

Analytic results for the resistivity of the two-channel Kondo lattice in a particular infinite dimensional limit (Lorentzian density of states) are presented. It is argued that in the absence of symmetry breaking phase transitions or applied fields there is a residual resistivity at zero temperature due to the spin disorder scattering off of the two-channel

K. Abe

We have determined the strong coupling alpha-s from a comprehensive study of energy-energy correlations (EEC) and their asymmetry (AEEC) in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. The data were compared with all four available predictions of QCD calculated up to O(alpha-s**2) in perturbation theory, and also with a resummed calc

J. O. Akeyo, H. F. Jones, C. S. Parker

The linear delta expansion is applied to a calculation of the SU(2) mass gap on the lattice. Our results compare favourably with the strong-coupling expansion and are in good agreement with recent Monte Carlo estimates.

G. Barnich, F. Brandt, M. Henneaux

We establish general theorems on the cohomology $H^*(s|d)$ of the BRST differential modulo the spacetime exterior derivative, acting in the algebra of local $p$-forms depending on the fields and the antifields (=sources for the BRST variations). It is shown that $H^{-k}(s|d)$ is isomorphic to $H_k(δ|d)$ in negative ghost degree $-k\ (k>0)$, where $δ$ is the

Shahn Majid, Henri Ruegg

We show that the $κ$-deformed Poincaré quantum algebra proposed for elementary particle physics has the structure of a Hopf agebra bicrossproduct $U(so(1,3))\cobicross T$. The algebra is a semidirect product of the classical Lorentz group $so(1,3)$ acting in a deformed way on the momentum sector $T$. The novel feature is that the coalgebra is also semidirect

P. S. Joshi, T. P. Singh

We consider here the gravitational collapse of a spherically symmetric inhomogeneous dust cloud described by the Tolman-Bondi models. By studying a general class of these models, we find that the end state of the collapse is either a black hole or a naked singularity, depending on the parameters of the initial density distribution, which are $ρ_{c}$, the ini

Danny Birmingham, Mark Rakowski

We study a class of subdivision invariant lattice models based on the gauge group $Z_{p}$, with particular emphasis on the four dimensional example. This model is based upon the assignment of field variables to both the $1$- and $2$-dimensional simplices of the simplicial complex. The property of subdivision invariance is achieved when the coupling parameter

A. Kwiatkowski, M. Steinhauser

QCD corrections to the electroweak one-loop result for the partial width $Γ(H\rightarrow b\bar{b})$ are studied. For the decay channel into bottom quarks the rate is affected by a virtual top quark through electroweak interactions. The calculation of QCD corrections to this quantity is performed for an intermediate range Higgs mass in the heavy top mass limi

V. Pasquier

In these lectures, I review some recent results on the Calogero-Sutherland model and the Haldane Shastry-chain. The list of topics I cover are the following: 1) The Calogero-Sutherland Hamiltonian and fractional statistics. The form factor of the density operator. 2) The Dunkl operators and their relations with monodromy matrices, Yangians and affine-Hecke a

Sadhan K. Adhikari, T. Frederico, I. D. Goldman, S. S. Sharma

A simple method for calculating the asymptotic $D$ state observables for light nuclei is suggested. The method exploits the dominant clusters of the light nuclei. The method is applied to calculate the $^4He$ asymptotic $D$ to $S$ normalization ratio $ρ^α$ and the closely related $D$ state parameter $D_2^α$. The study predicts a correlation between $D_2^α$ a