November 1996 arXiv papers — page 13

O. J. P. Eboli, E. M. Gregores, F. Halzen

The reason why some data on the production of $ψ$- and $Υ$-states disagree with QCD predictions, occasionally by well over one order of magnitude, is that the traditional method for performing the perturbative calculation of the cross section is simply wrong. The key mistake is to require that the heavy quark pair forms a color singlet at short distances, gi

Piotr A. Raczka

The QCD corrections to the R_τ^{12} moment of the invariant mass distribution in hadronic decays of the tau lepton are discussed. The next-to-next-to-leading order prediction is shown to be stable with respect to change of the renormalization scheme, provided that the contour integral expression is used. The optimized predictions are obtained using the princ

M. Burkardt, M. R. Frank, K. L. Mitchell

We apply Euclidean time methods to phenomenological Dyson-Schwinger models of hadrons. By performing a Fourier transform of the momentum space correlation function to Euclidean time and by taking the large Euclidean time limit, we project onto the lightest on-mass-shell hadron for given quantum numbers. The procedure, which actually resembles lattice gauge t

M. Gronau

The subject of CP violation in B decays is reviewed in the Standard Model (SM) and beyond the SM. The present explanation of CP violation in terms of phases in the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be tested through a variety of CP asymmtries in neutral and charged B decays. SM constraints on the CKM phases are violated by new mechanisms of CP nonco

John Ellis

The present status of the Standard Model and its experimental tests are reviewed, including indications on the likely mass of the Higgs boson. Also discussed are the motivations for supersymmetry and grand unification, searches for sparticles at LEP, neutrino oscillations, and the prospects for physics at the LHC.

S. V. Goloskokov, S. P. Kuleshov, O. V. Selyugin

The spin correlation parameters, polarization - $A_{N}$ and double spin correlation parameters - $A_{NN}$, are calculated in the framework of dynamical model (GKS) of the hadron-hadron interection in the whole region of small angles and for energy HERA-N $\sqrt{s}=40 GeV$. It is shown that the measurements of such spin effects at small trunsfer momenta, in t

U. Ellwanger, M. Rausch de Traubenberg, C. A. Savoy

The supersymmetric extension of the standard model with an additional gauge singlet is analysed in detail in the light of the recent experimental bounds on supersymmetric particles. The useful part of the parameter space and the particle spectrum are displayed. We find that once the recent bounds on the chargino mass are imposed, all other new particles prac

Jueping Liu, Werner Wetzel

In this paper we continue previous efforts in the literature to determine phenomenological values for the gluon mass by confronting theoretical results obtained in a theory of massive gluons with experimental values or results directly referring to the nontrivial structure of the Yang-Mills vacuum, e.g. to the presence of the gluon condensate. The decays of

Gerhard A. Schuler

A Monte Carlo program is presented for the computation of the most general cross section for two-photon production in e+e- collisions at fixed two-photon invariant mass W. Functions implemented for the five gamma* gamma* structure functions include three models of the total hadronic cross section and the lepton-pair production cross section. Prospects of a s

Giampiero Passarino

For the first time at LEP most of the events will have four fermions in the finals state and we have the unique opportunity of testing a complete calculation with the experimental data, well beyond the usual approximation of computing production cross section times branching ratios of Higgs into decay products. Calculation of the total cross sections and of

A. Datta, X. Zhang

New physics associated with the heavy top quark can affect top quark production and the partial decay width of $Z \rightarrow b \bar b$. In this paper, we examine the correlated effects of possible new physics on ${R_b}$ measured at LEP I and the single top quark production rate at Tevatron by using an effective lagrangian technique. We point out that certai

M. Talevi

Some recent developments in the calculation of weak matrix elements on the lattice are reviewed. In particular, we concentrate on the application of MPSTV non-perturbative renormalization method to the operators relevant to kaon physics. The chiral behaviour of the $B_K$ parameter and the long-standing question of the $ΔI=1/2$ rule are discussed.

K. Scharnhorst

Within Euclidean lattice field theory an exact equivalence between the one-flavour 2D Thirring model with Wilson fermions and Wilson parameter $r = 1$ to a two-colour loop model on the square lattice is established. For non-interacting fermions this model reduces to an exactly solved loop model which is known to be a free fermion model. The two-colour loop m

S. Aid

The scale dependence of the evolution of photoproduction cross sections with the photon-proton centre of mass energy W is studied using low Q^2 < 0.01 GeV^2 e^+p interactions collected by the H1 experiment at HERA. The value of the largest transverse momentum of a charged particle in the photon fragmentation region is used to define the hard scale. The slope

G. Amelino-Camelia

When quantum mechanical and general relativistic effects are taken into account in the analysis of distance measurements, one finds a measurability bound. I observe that some of the structures that have been encountered in the literature on the Quantum $κ$-Poincarè Group naturally lead to this bound.

M. Hortacsu, N. Ozdemir

We extend the work done for cosmic strings and show that for a more general class of locally flat metrics the one loop calculation do not introduce any new divergences to the VEV of the energy of a scalar particle. We explicitly perform the calculation for the configuration where we have one cosmic string in the presence of a dipole made out of cosmic string

Shuhei Mano, Eiichi Takasugi

The analytical solutions reported in our previous paper are given as series of hypergeometric or Coulomb wave functions. By using them, we can get the Teukolsky functions analytically in a desired accuracy. For the computation, the deep understanding of their properties is necessary. We summarize the main result: The relative normalization between the soluti

M. Azzouz, B. Dumoulin, A. Benyoussef

Heisenberg ladders are investigated using the bond-mean-field theory [M.Azzouz, Phys. Rev. B 48, 6136 (1993)]. The zero inter-ladder coupling energy gap, the uniform spin susceptibility and the nuclear magnetic resonance spin-relaxation rate are calculated as a function of temperature and magnetic field. For weakly coupled ladders, the energy spectrum vanish

Kun Yang, R. N. Bhatt

We report results of a numerical study of noninteracting electrons moving in two dimensions, in the presence of a random potential and a random magnetic field for a sequence of finite sizes, using topological properties of the wave functions to identify extended states. Our results are consistent with the existence of a second order localization-delocalizati

Pradeep Kumar

The following is a thermodynamic analysis of a III order (and some aspects of a IV order) phase transition. Such a transition can occur in a superconductor if the normal state is a diamagnet. The equation for a phase boundary in an H-T (H is the magnetic field, T, the temperature) plane is derived. by considering two possible forms of the gradient energy, it

N. Provatas, M. Haataja, E. Seppälä, S. Majaniemi

This paper studies growth, percolation, and correlations in disordered fiber networks. We start by introducing a 2D continuum deposition model with effective fiber-fiber interactions represented by a parameter $p$ which controls the degree of clustering. For $p=1$, the deposited network is uniformly random, while for $p=0$ only a single connected cluster can

Marcelo J. Rozenberg

We obtain exact numerical solutions of the degenerate Hubbard model in the limit of large dimensions (or large lattice connectivity). Successive Mott-Hubbard metal insulator transitions at integer fillings occur at intermediate values of the interaction and low enough temperature in the paramagnetic phase. The results are relevant for transition metal oxides

Leticia F. Cugliandolo, Jorge Kurchan, Luca Peliti

We show that, in nonequilibrium systems with small heat flows, there is a time-scale dependent effective temperature which plays the same role as the thermodynamical temperature, in that it controls the direction of heat flows and acts as a criterion for thermalization. We simultaneously treat the case of stationary systems with weak stirring and of glassy s

Norbert Schultka

Using Monte Carlo methods, we compute the finite-size scaling function of the helicity modulus $Υ$ of the two-dimensional O(3) model and compare it to the low temperature expansion prediction. From this, we estimate the range of validity for the leading terms of the low temperature expansion of the finite-size scaling function and for the low temperature exp

M. R. Kibler, J. Meyer, M. Daoud

The Bose distribution for a gas of nonrelativistic free bosons is derived in the framework of $qp$-deformed second quantization. Some thermodynamical functions for such a system in D dimensions are derived. Bose-Einstein condensation is discussed in terms of the parameters q and p as well as a parameter $ν_0&#39;$ which characterizes the representation space

M. P. Solf, T. A. Vilgis

We present a novel and rigorous approach to the Langevin dynamics of ideal polymer chains subject to internal distance constraints. The permanent constraints are modelled by harmonic potentials in the limit when the strength of the potential approaches infinity (hard crosslinks). The crosslinks are assumed to exist between arbitrary pairs of monomers. Formal

J. M. Deutsch, Hyoungsoo Yoon

A new technique for the separation of macromolecules is proposed and investigated. A thin mesh with pores comparable to the radius of gyration of a free chain is used to filter chains according to their length. Without a field it has previously been shown that the permeability decays as a power law with chain length. However by applying particular configurat

D. Braun, M. Kus, K. Zyczkowski

We analyze the density of roots of random polynomials where each complex coefficient is constructed of a random modulus and a fixed, deterministic phase. The density of roots is shown to possess a singular component only in the case for which the phases increase linearly with the index of coefficients. This means that, contrary to earlier belief, eigenvector

K. M. Perrett, D. A. Hanes, S. T. Butterworth, JJ Kavelaars

The two brightest elliptical galaxies in the Eridanus A group, NGC 1400 and NGC 1407, have been observed in both the Washington T_1 and Kron-Cousins I filters to obtain photometry of their globular cluster systems (GCSs). This group of galaxies is of particular interest due to its exceptionally high M/L value, previously estimated at ~3000h, making this clus

P. L. Schechter, C. D. Bailyn, R. Barr, R. Barvainis

Optical photometry is presented for the quadruple gravitational lens PG1115+080. A preliminary reduction of data taken from November 1995 to June 1996 gives component ``C&#39;&#39; leading component ``B&#39;&#39; by 23.7+/-3.4 days and components ``A1&#39;&#39; and ``A2&#39;&#39; by 9.4 days. A range of models has been fit to the image positions, none of whi

Konrad Kuijken

The normal mode theory for warping of galaxy disks, in which disks are assumed to be tilted with respect to the equator of a massive, flattened dark halo, assumes a rigid, fixed halo. However, consideration of the back-reaction by a misaligned disk on a massive particle halo shows there to be strong coupling leading to efficient damping (or in some circumsta

Tomasz Bulik, Donald Q. Lamb

We investigate the viability of Galactic corona models of gamma-ray bursts by calculating the spatial distribution expected for a population of high-velocity neutron stars born in the Galactic disk and moving in a gravitational potential that includes the Galactic bulge, disk, and a dark matter halo. We consider models in which the bursts radiate isotropical

Laura Maraschi, Francesco Haardt

The current status of understanding of the X-ray emission from Seyfert galaxies involves Comptonization of soft photons by hot subrelativistic electrons. After briefly reviewing the early theoretical basis for the presence of hot optically thin plasma in or around accretion disks and the key observations that led to develop the presently popular model of an

Wolfgang Brandner, Eva K. Grebel, You-Hua Chu, Kerstin Weis

We have identified a ring-shaped emission-line nebula and a possible bipolar outflow centered on the B1.5 supergiant Sher #25 in the Galactic giant HII region NGC 3603 (distance 6 kpc). The clumpy ring around Sher #25 appears to be tilted by 64 deg against the plane of the sky. Its semi-major axis (position angle approx. 165 deg) is 6.9" long, which correspo

Erik Kuulkers, Michiel van der Klis, Arvind N. Parmar

We have re-analyzed two EXOSAT Medium Energy observations during part of the 1984 X-ray outburst of the black-hole candidate transient system 4U 1630-47. One observation (May 10) shows fast timing properties (on timescales shorter than ~250 s) typical of those of other black hole candidates in their high states. The power-spectrum shows a power law with inde

H. Krawczynski, B. Funk, the HEGRA collaboration, S. Barthelmy

The HEGRA experiment is an air shower detector system for the study of neutral and charged cosmic rays in the energy range between 500 GeV to 10 PeV. Here we give an overview of how the HEGRA detector is used to search for TeV gamma-radiation associated with Gamma-Ray Bursts (GRBs) registered with the Burst And Transient Source Experiment (BATSE) on board th

Piercarlo Bonifacio, Paolo Molaro

Lithium abundances in a selected sample of halo stars have been revised by using the new accurate IRFM effective temperatures by Alonso, Arribas & Martinez-Roger (1996a). From 41 plateau stars (Teff > 5700 and [Fe/H] <= -1.5) we found no evidence for intrinsic dispersion, a tiny trend with Teff and no trend with [Fe/H]. The trend with the Teff is fully consi

Harry Tamvakis

Let F be the complete flag variety over Spec(Z) with the tautological filtration 0 \subset E_1 \subset E_2 \subset ... \subset E_n=E of the trivial bundle E over F. The trivial hermitian metric on E(\C) induces metrics on the quotient line bundles L_i(\C). Let \hat{c}_1(L_i) be the first Chern class of L_i in the arithmetic Chow ring \hat{CH}(F) and x_i = -\

Kyungsun Moon

Double-layer quantum Hall systems with spontaneous broken symmetry can exhibit a novel manybody quantum Hall effect due to the strong interlayer coherence. When the layer separation becomes close to the critical value, quantum fluctuations can destroy the interlayer coherence and the quantum Hall effect will disappear. We calculate the renormalized isospin s

Lawrence M. Krauss, Hong Liu

We present results obtained by a consideration of the non-classical energy momentum tensor associated with Euclidean Instantons outside the event horizon of black holes. We demonstrate here how this allows an analytic estimate to be made of the effect of discrete quantum hair on the temperature of the black hole, in which the role of violations of the weak e

T. Fukui, M. Sigrist, N. Kawakami

We investigate a model for the regularly depleted two-leg spin ladder systems. By using Lieb-Schultz-Mattis theorem, it is rigorously shown that this model realizes massless excitations or, alternatively, a degenerate ground state, although the original spin ladder system has a spin gap and a unique ground state. The ground state of the depleted model is eit

Gautam Bhattacharyya, Andrea Romanino

The question of naturalness is addressed in the context of gauge-mediated supersymmetry breaking models. Requiring that $M_Z$ arises naturally imposes upper limits on the right-handed selectron mass in these models that are stronger than in the Minimal Supersymmetric Standard Model and are interesting from the point of view of searches at the current and fut

Michael Aizenman

Scaling limits of critical percolation models show major differences between low and high dimensional models. The article discusses the formulation of the continuum limit for the former case. A mathematical framework is proposed for the direct description of the limiting continuum theory. The resulting structure is expected to exhibit strict conformal invari

G. Papadopoulos

We review the evidence for the various dualities amongst the five D=10 superstring theories and for the existence of M-theory using the associated effective supergravity theories. We also summarise the combinatorial technics developed for constructing BPS solutions in D=11 supergravity theory and conjecture that all the BPS solutions of D<11 supergravity the

Andrzej Czarnecki, Bernd Krause

Two-loop electroweak corrections to the electron, muon, and tau lepton anomalous magnetic moments have been computed recently. Effects of hadronic contributions to the photon propagator in two-loop QED corrections have also been reanalysed. The common technique used in both calculations was asymptotic expansion of Feynman diagrams in the ratio of lepton mass

Alexei G. Kritsuk

A two-component isothermal equilibrium model is applied to reproduce basic structural properties of dynamically hot stellar systems immersed in their massive dark haloes. The origin of the fundamental plane relation for giant ellipticals is naturally explained as a consequence of dynamical equilibrium in the context of the model. The existence of two galacti

J. Buenemann, W. Weber

We have generalized the Gutzwiller method to the cases of n=>2 correlated bands and report studies on a degenerate two-band model with Hund&#39;s rule type on-site interactions. At half band filling the metal-insulator transitions are usually of first order.

J. Wosiek, R. A. Janik

A new method is applied to solve the Baxter equation for the one dimensional system of noncompact spins. Dynamics of such an ensemble is equivalent to that of a set of reggeized gluons exchanged in the high energy limit of QCD amplitudes. The technique offers more insight into the old calculation of the intercept of hard Pomeron, and provides new results in

Deepak Dhar, Prabodh Shukla, James P. Sethna

We consider the single-spin-flip dynamics of the random-field Ising model on a Bethe lattice at zero temperature in the presence of a uniform external field. We determine the average magnetization as the external field is varied from minus infinity to plus infinity by setting up the self-consistent field equations, which we show are exact in this case. We fi

Mikhail Vasiliev

We review the theory of higher-spin gauge fields in four and three space-time dimensions and present some new results on higher-spin gauge interactions of matter fields in two dimensions.

Peter Boschan, Peter Biltzinger

We solve the recombination equation by taking into account the induced recombinations and a physical cut off in the hydrogen spectrum. The effective recombination coefficient is parametrized as a function of temperature and free electron density and is about a factor of four larger than without the induced recombination. This accelerates the last stage of th

I. Aref&#39;eva, A. Volovich

We use a simple algebraic method to find a special class of composite p-brane solutions of higher dimensional gravity coupled with matter. These solutions are composed of n constituent p-branes corresponding n independent harmonic functions. A simple algebraic criteria of existence of such solutions is presented. Relations with D=11,10 known solutions are di

C. Bourrely, J. Soffer

In view of the realistic possibility for operating high-energy polarized proton beams in future collider machines, it is highly desirable to propose for such beams, an absolute calibration allowing to measure accurately their degree of polarization. We consider more specifically one practical method based on pp elastic scattering near the forward direction a

A. Pashnev, M. Tsulaia

The free field theory for Regge trajectory is described in the framework of the BRST - quantization method. The physical spectrum includes daugther trajectories along with parent one. The applicability of the BRST approach to the description of a single Regge trajectory without its daughter trajectories is discussed. The simple example illustrates the approp

N. Fornengo, C. Giunti, C. W. Kim, J. Song

The propagation of neutrinos in a gravitational field is studied. A method of calculating a covariant quantum-mechanical phase in a curved space-time is presented. The result is used to calculate gravitational effects on the neutrino oscillation in the presence of a gravitational field. We restrict our discussion to the case of the Schwartzschild metric. Spe

Carlos O. Lousto, Francisco D. Mazzitelli

We find a self-consistent pp-gravitational shock wave solution to the semiclassical Einstein equations resulting from the $1/N$ approach to the effective action. We model the renormalized matter stress-energy-momentum tensor by $N$ massless scalar fields in the Minkowski vacuum plus a classical particle. We show that quantum effects generate a milder singula

Zoltan Haiman, Abraham Loeb

The high ionization level and universal metallicity (1% solar) of the intergalactic gas at redshifts z<5 implies that nonlinear structure had started to form in the universe at earlier times than we currently probe. In Cold Dark Matter (CDM) cosmologies, the first generation of baryonic objects emerges at redshifts z=10-50. Here we examine the observable con

Jonathan A. Bagger, Konstantin T. Matchev, Damien M. Pierce, Ren-Jie Zhang

We examine gauge and Yukawa coupling unification in models with gauge-mediated supersymmetry breaking. We work consistently to two-loop order, and include all weak, messenger and unification-scale threshold corrections. We find that successful unification requires unification-scale threshold corrections that are in conflict with the minimal SU(5) model, but

F. Lesage, H. Saleur

We study response functions of integrable quantum impurity problems with an external field at $T=0$ using non perturbative techniques derived from the Bethe ansatz. We develop the first steps of the theory of excitations over the new, field dependent ground state, leading to renormalized (or ``dressed&#39;&#39;) form-factors. We obtain exactly the low freque

Charles H. Bennett, Christopher A. Fuchs, John A. Smolin

We consider the problem of trying to send a single classical bit through a noisy quantum channel when two transmissions through the channel are available as a resource. Classically, two transmissions add nothing to the receiver&#39;s capability of inferring the bit. In the quantum world, however, one has the possible further advantage of entangling the two t

David A. Meyer

Classical lattice gas automata effectively simulate physical processes such as diffusion and fluid flow (in certain parameter regimes) despite their simplicity at the microscale. Motivated by current interest in quantum computation we recently defined quantum lattice gas automata; in this paper we initiate a project to analyze which physical processes these

S. Majid

Double-bosonisation associates to a braided group in the category of modules of a quantum group, a new quantum group. We announce the semiclassical version of this inductive construction.

R. Haeckl, V. Hund, H. Pilkuhn

It is shown that the potential for lepton-antilepton bound states (leptonium) is the Fourier transform of the first Born approximation to the QED scattering amplitude in an 8-component equation, while 16-component equations are excluded. The Fourier transform is exact at all cms energies $-\infty < E < \infty$; the resulting atomic spectrum is explicitly CPT

Ola Tornkvist, Elsebeth Schroder

We derive the exact equation of motion for a vortex in two- and three- dimensional non-relativistic systems governed by the Ginzburg-Landau equation with complex coefficients. The velocity is given in terms of local gradients of the magnitude and phase of the complex field and is exact also for arbitrarily small inter-vortex distances. The results for vortic

Frank X. Lee, Derek B. Leinweber, Xuemin Jin

Two new sets of QCD sum rules for the nucleon axial coupling constants are derived using the external-field technique and generalized interpolating fields. An in-depth study of the predicative ability of these sum rules is carried out using a Monte-Carlo based uncertainty analysis. The results show that the standard implementation of the QCD sum rule method

Y. -Z. Qian, W. C. Haxton, K. Langanke, P. Vogel

In order to explore the consequences of the neutrino irradiation for the supernova r-process nucleosynthesis, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich heavy nuclei, and estimate the average number of neutrons emitted in the resulting spallation. Our results suggest that charged-current $ν_e$ captures ca

Pavlos Protopapas, Abraham Klein

The most consistently useful simple model for the study of odd deformed nuclei, the particle-rotor model (strong coupling limit of the core-particle coupling model) has nevertheless been beset by a long-standing problem: It is necessary in many cases to introduce an ad hoc parameter that reduces the size of the Coriolis interaction coupling the collective an

Jorge G. Hirsch, Peter O. Hess, Osvaldo Civitarese

The validity of the pn-QRPA and -RQRPA descriptions of double beta decay transition amplitudes is analyzed by using an exactly solvable model. It is shown that the collapse of the QRPA is physically meaningful and that it is associated with the appearance of a state with zero energy in the spectrum. It is shown that in the RQRPA this particular feature is no

E. A. Pasyuk, V. Yu. Alexakhin, S. I. Gogolev, K. O. Oganesyan

A study of the reaction pi+ + d --> p + p has been performed in the energy range of 18 - 44 MeV. Total cross sections and differential cross sections at six angles have been measured at 15 energies with an energy increment of 1 - 2 MeV. This is the most systematic data set in this energy range. No structure in the energy dependence of the cross section has b

Domingo Louis-Martinez

It is shown that the Callan-Giddings-Harvey-Strominger theory on the cylinder can be consistently quantized (using Dirac&#39;s approach) without imposing any constraints on the sign of the gravitational coupling constant or the sign (or value) of the cosmological constant. The quantum constraints in terms of the original geometrical variables are also derive

A. P. C. Malbouisson, B. F. Svaiter, N. F. Svaiter

We analyse the one-loop fermionic contribution for the scalar effective potential in the temperature dependent Yukawa model. In order to regularize the model a mix between dimensional and analytic regularization procedures is used. We find a general expression for the fermionic contribution in arbitrary spacetime dimension. It is found that in D=3 this contr

G. Amelino-Camelia, D. Bak, D. Seminara

String-inspired 1+1-dimensional gravity is coupled to Yang-Mills fields in the Cangemi-Jackiw gauge-theoretical formulation, based on the extended Poincaré group. A family of couplings, which involves metrics obtainable from the physical metric with a conformal rescaling, is considered, and the resulting family of models is investigated both at the classical

M. Gomes, J. M. C. Malbouisson, A. J. da Silva

We determine the |p|/m expansion of the two body scattering amplitude of the quantum theory of a Chern-Simons field minimally coupled to a scalar field with quartic self-interaction. It is shown that the existence of a critical value of the self-interaction parameter for which the 2-particle amplitude reduces to the Aharonov-Bohm one is restricted to the lea

P. Di Vecchia, L. Magnea, R. Marotta, A. Lerda

We report on recent progress in the use of string techniques for the computation of field theory amplitudes. We show how one-loop renormalization constants in Yang-Mills theory can be computed using the open spinning string, we review the calculation of two-loop scalar amplitudes with the bosonic string, and we briefly indicate how the technique can be appli

Shinji Hamamoto

Covariant forms are given to a gauge theory of massive tensor field. This is accomplished by introducing another auxiliary field of scalar type to the system composed of a symmetric tensor field and an auxiliary field of vector type. The situation is compared to the case of the theory in which a tensor field describes a scalar ghost as well as an ordinary ma

Robert G. Leigh, Matthew J. Strassler

We note that the accidental symmetries which are present in some examples of duality imply the existence of continuously infinite sets of theories with the same infrared behavior. These sets interpolate between theories of different flavors and colors; the change in color and flavor is compensated by interactions (often non-perturbative) induced by operators

Gordon P. Ramsey

I review the constituent contributions to the spin of the proton extracted from recent data at CERN, SLAC and DESY. The valence, sea quark and antiquark spin-weighted distributions are determined separately. The data appear to imply a small to moderate polarized gluon distribution, so that the anomaly term is not significant in determining these contribution

Charles A. Nelson

In a recent paper, 8 semileptonic parameters were defined to specify the most general Lorentz-invariant spin correlation functions for 2-body tau decays. These parameters can be used to search for anomalous longitudinal-versus transverse polarized-partial widths, for non-CKM-type leptonic CP violation, and for leptonic T violation. They can also be used to b

Tim Tait, C. --P. Yuan

Continuing earlier work, we examine the constraint on an anomalous t-c-g coupling from top quark decay. We find that from current CDF measurements of the branching ratio $t \rightarrow W b$, the minimum scale at which new physics can strongly modify the t-c-g coupling is \Ltcg $\geq$ about 950 GeV. At the upgraded Tevatron, single top production can constrai

M. R. Pennington

This talk, given at the Second Workshop on ELFE Physics, St Malo, France, September 1996, presents a brief review of the progress that has been made in calculating the properties of hadrons in strong QCD.

S. Willenbrock

I review recent theoretical work on top-quark physics within the standard model, beyond the standard model, and at the Planck scale.

G. Altarelli

The status of precision tests of the Standard Model is reviewed.

B. S. Zou

Violations of the Okubo-Zweig-Iizuka (OZI) rule in $s\bar s <-> n\bar n = 1/2 (u\bar u + d\bar d)$ mixing and $ϕ$ production from nucleon-antinucleon annihilation are reviewed. Possible explanations are examined. We conclude that the two-step hadronic loops can explain these OZI violations naturally with proper consideration of cancellations between loops. N

Marco Fabbrichesi, Francesco Vissani

The muon transverse polarization in the $K^+ \leftarrow π^0 μ^+ ν_μ$ decay will be measured at the $10^{-4}$ level in forthcoming experiments. We compare the phenomenological perspectives with the theoretical predictions in supersymmetric extensions of the standard model. In the minimal extension, CP-violating phases lead to a non-zero transverse polarizatio

P. Colangelo

I discuss a QCD sum rule determination of the four-quark operator matrix elements contributing to the $Λ_b$ inclusive decay rates at the order $m_b^{-3}$. The results suggest that $1/m_b^3$ corrections are not responsible of the observed difference between the lifetimes of $Λ_b$ and $B_d$.

B. S. Zou

From a re-analysis of pi+ pi- -> pi+ pi- and pi+ pi- -> K K data, we found for pi-pi S-wave interaction below 2 GeV, sigma(400), f0(980), f0(1500) and f0(1780) clearly show up. f0(1370) can be included with a very small branching ratio to pi-pi. f0(1300) and f0(1590) are not real resonances and are due to interference effects of above resonances. The sigma(4

J. Soffer, O. Teryaev

We perform the isospin decomposition of proton and neutron SLAC data in the region $0.01 \leq x \leq 0.1$. The isovector part is well described by a power behaviour $x^α$, where $α$ leads to the validity of Bjorken sum rule and it is consistent with the power extracted from all previous data using NLO evolution. The isoscalar part behaviour may be interprete

W. Beenakker, R. Hoepker, M. Spira

A Fortran-program for the production cross-sections of squarks and gluinos at hadron colliders is described. It includes full next-to-leading order SUSY-QCD corrections to all possible final states ($\squark\squarkbar, \gluino\gluino, \squark\gluino, \squark\squark$). The program allows to calculate total cross-sections as well as differential distributions

I. I. Balitsky, V. M. Braun, Y. Koike, K. Tanaka

We prove that the twist-3 chiral-odd parton distributions obey simple GLAP evolution equations in the limit $N_c\to\infty$ and give analytic formulae for the corresponding anomalous dimensions. The results are valid to O(1/N_{c}^2) accuracy and will be useful in confronting with future experiments.

M. -P. Lombardo

We study the interplay of quark number density and chiral symmetry in lattice QCD. We suggest that both are controlled by the eigenvalue spectrum of the fermionic propagator matrix, which shapes the pattern of zeros of the partition function. The onset of the quark current would be triggered by the lowest lying eigenvalue, the chiral transition by the densit

Reinhard A. Schumacher

Experimental evidence from coherent diffractive proton scattering has been reported for two narrow baryonic resonances which decay predominantly to strange particles. These states, with masses close to 2.0 GeV would, if confirmed, be candidates for hidden strangeness states with unusual internal structure. In this paper we examine the literature on strangene

R. De Paola, N. F. Svaiter

We consider a monopole detector interacting with a massive scalar field. The radiative processes are discussed from the accelerated frame point of view. After this, we obtain the Minkowski vacuum stress tensor measured by the accelerated observer using a non-gravitational stress tensor detector as discussed by Ford and Roman (PRD 48, 776 (1993)). Finally, we

Nicholas G. Phillips, B. L. Hu

For quantum fields on a curved spacetime with an Euclidean section, we derive a general expression for the stress energy tensor two-point function in terms of the effective action. The renormalized two-point function is given in terms of the second variation of the Mellin transform of the trace of the heat kernel for the quantum fields. For systems for which

A. Zhuk

It is shown that a transition from a multidimensional cosmological model with one internal space of the dimension d_1 to the effective tree-level bosonic string corresponds to an infinite number of the internal dimensions: d_1 -> infinity.

M. D. Maia

The concept of time is discussed in the context of the canonical formulation of the gravitational field. Using a hypersurface orthogonal foliation, the arbitrariness of the lapse function is eliminated and the shift vector vanishes, allowing a consistent definition of time.

N. Shnerb

Low-temperature dynamics of flux lines in high temperature, type II, superconductors in the presence of correlated disorder in the form of columnar defects is discussed. The effect of tilting the applied magnetic field with respect to the column&#39;s directions is considered, using the non-Hermitian quantum mechanics technique evaluated by Hatano and Nelson

H. Mathur

The two dimensional surface of an integer quantum hall multilayer is mapped onto a Heisenberg spin-chain with ferromagnetic coupling. Using this mapping it is shown non-perturbatively that the surface states constitute a very anisotropic metal in the infinite size limit. For multilayers of finite size, two diffusive mesoscopic regimes are identified and the

Felix Ritort

In this talk I review some recent developments which shed light on the main connections between structural glasses and mean-field spin glass models with a discontinuous transition. I also discuss the role of quantum fluctuations on the dynamical instability found in mean-field spin glasses with a discontinuous transition. In mean-field models with pairwise i

R. Eder, Y. Ohta, G. A. Sawatzky

We present an exact diagonalization study of the single particle spectral function in the so-called t-t&#39;-t&#39;&#39;-J model in 2D. As a key result, we find that unlike the `pure&#39; t-J model, hole doping leads to a major reconstruction of the quasiparticle band structure near (pi,0): whereas for the undoped system the quasiparticle states near (pi,0)

J. Buenemann, W. Weber

Using the generalized Gutzwiller method we present results on the ferromagnetic behavior of extended Hubbard models with two degenerate eg orbitals. We find significant differences to results obtained from Hartree-Fock theory.