July 1995 arXiv papers — page 7

Marcello Ciafaloni

The consistency of the BFKL equation with the renormalization group is investigated at next-to-leading log-x level.By use of Kt-factorization, it is found that,besides next-to-leading small-x resummation formulae, a leading, x-dependent redefinition of initial quarks and gluons is needed. Its interpretation and phenomenological relevance are discussed.

M. Benmerrouche, G. Orlandini, T. G. Steele

A new technique based on Hölder's integral inequality is applied to QCD sum-rules to provide fundamental constraints on the sum-rule parameters. These constraints must be satisfied if the sum-rules are to consistently describe integrated physical cross-sections, but these constraints do not require any experimental data and therefore can be applied to an

Andrzej J. Buras, Robert Fleischer

We present strategies for determining electroweak penguins from experimental data. Using the CKM-angle $γ$ as one of our central inputs and making some reasonable approximations, we show that the $\bar b\to\bar s$ electroweak penguin amplitude can be determined in a two-step procedure involving i) BR$(B^+\toπ^0K^+)$, BR$(B^-\toπ^0K^-)$, BR$(B^+\toπ^+K^0)$ an

B. Bajc, S. Fajfer, R. J. Oakes

Combining heavy quark effective theory and the chiral Lagrangian approach we investigate D meson radiative decays. First, we reanalyse $D^{*} \rightarrow D γ$ decays using heavy quark spin symmetry, chiral symmetry Lagrangian, but including also the light vector mesons. Then, we calculate branching ratios $D \rightarrow V γ$. We make some comments on the Cab

N. Brambilla, G. M. Prosperi, A. Vairo

First we review the derivation of the relativistic flux tube model for a quark-antiquark system from Wilson area law as we have given in a preceding paper. Then we extend the method to the three-quark case and obtain a Lagrangian corresponding to a star flux tube configuration. A Hamiltonian can be explicitly constructed as an expansion in $1 / m^2$ or in th

G. C. Branco, J. I. Silva-Marcos

We study the question of calculability of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements within the framework of universal strength for Yukawa couplings (USY). We first classify all solutions leading to $m_u=m_d=0$ within USY and then suggest a highly predictive ansatz where all the moduli of the CKM matrix elements are correctly predicted in terms of q

P. Kroll, M. Schürmann, P. A. M. Guichon

The amplitudes for virtual Compton scattering off protons are calculated within the framework of the diquark model in which protons are viewed as being built up by quarks and diquarks. The latter objects are treated as quasi-elementary constituents of the proton. Virtual Compton scattering, electroproduction of photons and the Bethe-Heitler contamination are

Rahul Basu, R. Parthasarathy

We propose a mechanism for instanton induced chiral symmetry breaking in QCD with fundamental scalars. The model Lagragian that we use has the same symmetry properties as QCD. The scalar fields develop vacuum expectation values at a non-trivial minimum and generate masses for thhe light quarks. The minimization condition is also used to break the $SU(N_f)$ f

Hidenaga Yamagishi, Ismail Zahed

The non-perturbative implications of BRST quantization are examined for $θ$ vacua and related issues. Strong CP violation is shown to be absent for QCD in the BRST formalism. Previous evidence for CP violation is reexamined, and much of it is found to be inconclusive. It is proposed that some lattice calculations be redone to clarify the situation. For the U

Pankaj Agrawal, Fredrick I. Olness, Stephan T. Riemersma, Wu-Ki Tung

There are presently two approaches to calculating heavy quark production for the deeply inelastic scattering process in current literature. The conventional fixed-flavor scheme focuses on the flavor creation mechanism and includes the heavy quark only as a final state particle in the hard scattering cross section; this has been computed to next-to-leading or

R. Brower, K. Orginos, Y. Shen, C-I Tan

We consider a particular 4 state spin system composed of two Ising spins (~$s_x, \; σ_x$~) with independent hopping parameters $κ_1, κ_2$, coupled by a bilinear Yukawa term, $y s_x σ_x$. The Yukawa term is solely responsible for breaking the global $ Z_2 \times Z_2$ symmetry down to $Z_2$. This model is intended as an illustration of general coupled Higgs sy

J. Ambjorn, J. Jurkiewicz, Y. Watabiki

We provide evidence that the Hausdorff dimension is 4 and the spectral dimension is 2 for two-dimensional quantum gravity coupled the matter with a central charge $c \leq 1$. For $c > 1$ the Hausdorff dimension and the spectral dimension monotonously decreases to 2 and 1, respectively.

Ady Stern, Bertrand I. Halperin

We analyze the linear response of a half filled Landau level to long wavelength and low frequency driving forces, using Fermi liquid theory for composite fermions. This response is determined by the composite fermions quasi--particle effective mass, $m^*$, and quasi--particle Landau interaction function $f(θ-θ')$. Analyzing infra--red divergences of pert

Heiko Rieger, A. Peter Young

The Ising spin glass model in a transverse field has a zero temperature phase transition driven solely by quantum fluctuations. This quantum phase transition occuring at a critical transverse field strength has attracted much attention recently. We report the progress that has been made via Monte Carlo simulations of the finite dimensional, short range model

Heiko Rieger

The dynamics of strongly disordered systems becomes extremely slow or glassy at low temperatures, which results in a characteristic aging scenario. This means that the outcome of measurements strongly depends on the history of the system within the glassy phase, even on macroscopic time scale like hours, weeks or years. This area of non-equilibrium dynamics

J. Kisker, L. Santen, M. Schreckenberg, H. Rieger

The low temperature dynamics of the two- and three-dimensional Ising spin glass model with Gaussian couplings is investigated via extensive Monte Carlo simulations. We find an algebraic decay of the remanent magnetization. For the autocorrelation function $C(t,t_w)=[< S_i(t+t_w)S_i(t_w)>]_{av}$ a typical aging scenario with a $t/t_w$ scaling is established.

M. E. J. Newman, G. T. Barkema

Using a cluster-flipping Monte Carlo algorithm combined with a generalization of the histogram reweighting scheme of Ferrenberg and Swendsen, we have studied the equilibrium properties of the thermal random-field Ising model on a cubic lattice in three dimensions. We have equilibrated systems of LxLxL spins, with values of L up to 32, and for these systems t

Yan V. Fyodorov, Alexander D. Mirlin

The random banded matrices (RBM) whose diagonal elements fluctuate much stronger than the off-diagonal ones were introduced recently by Shepelyansky as a convenient model for coherent propagation of two interacting particles in a random potential. We treat the problem analytically by using the mapping onto the same supersymmetric nonlinear $σ-$model that app

Francine R. Marleau, Charles C. Dyer, Jody H. Palmer

We re-analyze the issue of redshifts induced by a moving cosmic string by looking at moving sources and observers on a conical spacetime in a fully relativistic approach. By replacing the concept of a moving spacetime with the more clearly defined concept of moving sources and observers in the string spacetime, we show that there is no effect: the only redsh

I. Horvath, P. Meszaros, A. Meszaros

We discuss detailed fits of the BATSE and PVO gamma-ray burst peak-flux distributions with Friedman models taking into account possible density evolution and standard candle or power law luminosity functions. A chi-square analysis is used to estimate the goodness of the fits and we derive the significance level of limits on the density evolution and luminosi

Øyvind Grøn, Harald H. Soleng

On the scales of galaxies and beyond there is evidence for unseen dark matter. In this paper we find the experimental limits to the density of dark matter bound in the solar system by studying its effect upon planetary motion.

Helen Tadros, George Efstathiou

We estimate the three-dimensional power spectrum of IRAS galaxies from the QDOT and $1.2$Jy redshift surveys. We use identical estimators for both surveys and show how the results depend on the weights assigned to the galaxies. The power spectrum for the QDOT survey is steeper and has a higher amplitude at wavenumbers $k \sim 0.05\; h {\rm Mpc}^{-1}$ (where

Jerzy Stelmach

It is well known that the $Λ$-term is a very good candidate for the smooth component of the universe since it resolves the so-called ``$Ω$-problem&#39;&#39; giving, at the same time, sufficiently large age of the universe. However, the constant $Λ$-term is not the only possibility. Some people consider the $Λ$-term varying in time according to the law $Λ\app

David Kaiser

Spectral indices from models of inflation which incorporate a Generalized Einstein Theory (GET) gravity sector are calculated to first order in a slow-roll expansion. By quantizing a suitably- generalized measure of the intrinsic curvature perturbation, the spectral indices as calculated in the Jordan frame now match those as calculated following a conformal

Esther M. Hu, Tae-Sun Kim, Lennox L. Cowie, Antoinette Songaila

We describe the properties of the Ly$\alpha$ forest in the column density range $\nhi \geq 2\times10^{12}$ cm$^{-2}$ based on 1056 lines in the wavelength range 4300--5100\AA measured in extremely high S/N, $R=36,000$ spectra of four quasars. The column density distribution is well described by a -1.5 power law to $2\times10^{12}$ cm$^{-2}$, below which limi

Sun Hong Rhie, David Bennett

We develop match probability statistics to test the recurrences of gamma ray bursts in the BATSE catalog 1B and 2B. We do not find a signal of repetitions at the match level of 1.e-3.

Tad Hogg, Bernardo A. Huberman, Michael Youssefmir

Recent developments in the global liberalization of equity and currency markets, coupled to advances in trading technologies, are making markets increasingly interdependent. This increased fluidity raises questions about the stability of the international financial system. In this paper, we show that as couplings between stable markets grow, the likelihood o

Alexander Berkovich, Barry M. McCoy, William P. Orrick

We prove polynomial identities for the N=1 superconformal model SM(2,4ν) which generalize and extend the known Fermi/Bose character identities. Our proof uses the q-trinomial coefficients of Andrews and Baxter on the bosonic side and a recently introduced very general method of producing recursion relations for q-series on the fermionic side. We use these po

J. A. Casas, A. Lleyda, C. Muñoz

A complete analysis of all the potentially dangerous directions in the field-space of the minimal supersymmetric standard model is carried out. They are of two types, the ones associated with the existence of charge and color breaking minima in the potential deeper than the realistic minimum and the directions in the field-space along which the potential bec

M. Biyajima T. Mizoguchi, T. Osada, G. Wilk

We applied an improved Coulomb correction method developed by us recently to data on identical KK-pairs production in S + Pb and p + Pb reactions at 200 GeV/c obtained by NA44 Collaboration. To analyse the whole range of the momentum transfers measured the method of &#34;seamless fitting&#34; has been proposed and used together with the asymptotic expansion

R. Schaefer, T. Fliessbach

The two-fluid model of liquid helium is generalized to the case that the superfluid fraction has a small entropy content. We present theoretical arguments in favour of such a small superfluid entropy. In the generalized two-fluid model various sound modes of He$\;$II are investigated. In a superleak carrying a persistent current the superfluid entropy leads

R. Schaefer, T. Fliessbach

This letter is based on the hypothesis of a small entropy content of the superfluid fraction of liquid helium. We show that such a superfluid entropy gives rise to a new sound mode in a ring-shaped superleak. This mode is named sixth sound. We propose an experiment by which its sound velocity and thereby the superfluid entropy can be measured. A negative exp

W. de Boer, G. Burkart, R. Ehret, W. Oberschulte-Beckmann

Within the Constrained Minimal Supersymmetric Standard Model (CMSSM) it is possible to predict the low energy gauge couplings and masses of the 3.generation particles from a few parameters at the GUT scale, and electroweak symmetry breaking. Further constraints can be derived from the branching ratio for the radiative (penguin) decay of the b-quark into s ga

Dong-Sheng Du, Mao-Zhi Yang, Deng-Zhi Zhang

The space-like penguin contributions to branching ratios and CP asymmetries in charmless decays of $B$ to two pseudoscalar mesons are studied using the next-to-leading order low energy effective Hamiltonian. Both the gluonic penguin and the electroweak penguin diagrams are considered. We find that the effects are significant.

Costas J. Efthimiou, Samwel A. Apikyan

We present an elementary introduction to the construction of integrable models on hyper-elliptic surfaces for non specialists; also, we present some of the details of the paper `solv-int/9504002&#39; for the more interested readers. (Based on a talk given at the MRST 95 meeting by C. E.)

Marco Frasca

We prove that, for a quantum system that undergoes a strong perturbation, the solution of the leading order equation of the strong field approximation (M.Frasca, Phys. Rev. A, {\bf 45}, 43 (1992)) can be derived by the adiabatic approximation. In fact, it is shown that greatest is the perturbation and more similar the quantum system is to an adiabatic one, t

A. P. Demichev

We show that R-matricies of all simple quantum groups have the properties which permit to present quantum group twists as transitions to other coordinate frames on quantum spaces. This implies physical equivalence of field theories invariant with respect to q-groups (considered as q-deformed space-time groups of transformations) connected with each other by

J. M. Holender, M. J. Gillan

Ab-initio dynamical simulation is used to study the liquid Ga-Se system at the three concentrations Ga$_2$Se, GaSe and Ga$_2$Se$_3$ at the temperature 1300~K. The simulations are based on the density functional pseudopotential technique, with the system maintained on the Born-Oppenheimer surface by conjugate gradients minimization. We present results for the

Axel Gross, Steffen Wilke, Matthias Scheffler

We report the first six-dimensional quantum dynamical calculations of dissociative adsorption and associative desorption. Using a potential energy surface obtained by density functional theory calculations, we show that the initial decrease of the sticking probability with increasing kinetic energy in the system H_2/Pd(100), which is usually attributed to th

J. Gegelia, A. Khelashvili, N. Kiknadze

On the example of topologically massive gauge field theory we find the origin of possible inconsistency of working with gauge fixing terms (together with relevant ghost sector)

P. P. Kulish

The definitions of the main notions related to the quantum inverse scattering methods are given. The Yang-Baxter equation and reflection equations are derived as consistency conditions for the factorizable scattering on the whole line and on the half-line using the Zamolodchikov-Faddeev algebra. Due to the vertex-IRF model correspondence the face model analo

Vu B Ho

It is shown that, with some reasonable assumptions, the theory of general relativity can be made compatible with quantum mechanics by using the field equations of general relativity to construct a Robertson-Walker metric for a quantum particle so that the line element of the particle can be transformed entirely to that of the Minkowski spacetime, which is as

M. Anselmino, I. Bediaga, E. Predazzi

In this paper the relevance of non-spectator decays of charm particles is analysed and some crucial tests for it are suggested.

Yosef Nir

If New Physics contributes significantly to neutral meson mixing, then it is quite likely that it does so in a CP violating manner. In $D^0-\bar D^0$ mixing measured through $D^0\rightarrow K^+π^-$, CP violation induces a term $\propto te^{-Γt}$ with important implications for experiments. For $B_s-\bar B_s$ mixing, a non-vanishing CP asymmetry (above a few

Kenneth Lane

I discuss production and detection at the Tevatron $\pbarp$ collider of pairs of light ($\mpi = 100$--$200\,\gev$) color--singlet technipions that are expected in all nonminimal models of technicolor. Gluon fusion production rates can be as large as $\CO(1\,\pb)$. Topcolor--assisted technicolor is required to prevent top quarks from decaying as $t \ra \tpip

Rajamani Narayanan, Herbert Neuberger

Golterman and Shamir falsely claim that a waveguide model modified by adding many charged bosonic spinors, in the limit of an infinite number of matter fields, becomes identical to the overlap if in the target theory every fermion appears in four copies. Their modified model would give wrong results even in the vectorial four flavor massless Schwinger model,

Vladimir Savinov, Roger Fulton

Using the CLEO-II detector at the CESR $e^+e^-$ storage ring running at the center-of-mass energy around 10.6 GeV, we have studied exclusive production of charmonium states in two-photon collisions. Employing a dataset comprising 3.0 ${\rm fb}^{-1}$ we have searched for decays of the $η_c$, $χ_{c0}$ and $χ_{c2}$ mesons resulting in four charged hadrons. We r

Vladimir Savinov

Using the CLEO-II detector, we have studied the exclusive two-photon production of the light pseudoscalar mesons in a single tagged mode. We report on a preliminary measurement of the $π^0$, $η$ and $η^{\prime}$ electromagnetic form factors in the $Q^2$ region from 2 ${\rm (GeV/c)}^2$ to 20 ${\rm (GeV/c)}^2$.}

Sergei D. Odintsov, Yongsung Yoon

Using Wilsonian procedure (renormalization group improvement) we discuss the finite quantum corrections to black hole entropy in renormalizable theories. In this way, the Wilsonian black hole entropy is found for GUTs (of asymptotically free form, in particularly) and for the effective theory of conformal factor aiming to describe quantum gravity in infrared

Andrei Barvinsky, Yuri Gusev

The generating function method is applied to the trace of the heat kernel and the one-loop effective action derived from the covariant perturbation theory. The basis of curvature invariants of second order for the heat kernel (Green function) is built and simple rules for form factor manipulations are proposed. The results are checked by deriving the Schwing

Don N. Page

Quantum mechanics may be formulated as SENSIBLE QUANTUM MECHANICS (SQM) so that it contains nothing probabilistic, except, in a certain frequency sense, conscious perceptions. Sets of these perceptions can be deterministically realized with measures given by expectation values of positive-operator-valued AWARENESS OPERATORS in a quantum state of the universe

Jun Zang, A. R. Bishop, D. Schmeltzer

We study the phase diagram, ground state properties, and excitation gaps of a frustrated spin-Peierls chain, i.e. a spin-Peierls chain with both nearest neighbor exchange $J_1$ and next nearest neighbor exchange $J_2$. The phase diagram is calculated using a bosonization Renormalization-Group (RG) method. We propose a (bosonic) bond-operator mean field appro

Chetan Nayak, Frank Wilczek

We derive the equilibrium and transport properties of metals using renormalization group equations and finite-size scaling. Particular attention is given to the well-known cases of Fermi and Luttinger liquids. An important subtlety is that the temperature dependence of many transport coefficients is determined by ``dangerous&#39;&#39; irrelevant operators. W

Eli Eisenberg, Asher Baram, Michael Baer

A direct and exact method for calculating the density of states for systems with localized potentials is presented. The method is based on explicit inversion of the operator $E-H$. The operator is written in the discrete variable representation of the Hamiltonian, and the Toeplitz property of the asymptotic part of the obtained {\it infinite} matrix is used.

Jukka A. Ketoja, Indubala I. Satija

The tight binding model for an electron on an anisotropic triangular lattice in a uniform magnetic field is studied using a decimation scheme. The model exhibits a transition from critical to localized phase and the phase diagram is described in terms of three nontrivial renormalization fixed points for the band edges. These subcritical, critical, and superc

Vaclav Janis, Jan Schlipf

A general expansion scheme based on the concept of linked cluster expansion from the theory of classical spin systems is constructed for models of interacting electrons. It is shown that with a suitable variational formulation of mean-field theories at weak (Hartree-Fock) and strong (Hubbard-III) coupling the expansion represents a universal and comprehensiv

I. Kh. Zharekeshev, B. Kramer

The distribution of energy level separations for lattices of sizes up to 28$\times$28$\times$28 sites is numerically calculated for the Anderson model. The results show one-parameter scaling. The size-independent universality of the critical level spacing distribution allows to detect with high precision the critical disorder $W_{c}=16.35$. The scaling prope

John McCabe, Tomasz Wydro

We exploit the identification between the critical theory of the 3-state Potts model and the D_5 conformal model. This allows us to determine all 3-point correlations involving the fields associated with the Potts order parameter and the energy density. The calculation uses screened Coulomb gas correlations. The Z_3 symmetry of the 3-state Potts model is man

Nicholas G. Phillips, A. Kogut

We use numerical simulations of the time evolution of global textures to investigate the relationship between ordering dynamics and energy density in an expanding universe. Events in which individual textures become fully wound are rare. The energy density is dominated by the more numerous partially wound configurations, with median topological charge alpha

Dennis Zaritsky, Ann I. Zabludoff, Jeffrey A. Willick

We develop a straightforward and quantitative two-step method for spectroscopically classifying galaxies from the low signal-to-noise (S/N) optical spectra typical of galaxy redshift surveys. First, using χ^2-fitting of characteristic templates to the object spectrum, we determine the relative contributions of the old stellar component, the young stellar com

James Robinson, Benjamin D. Wandelt

We find constraints on the generation of super-causal-horizon energy perturbations from a smooth initial state, under a simple physical scheme. We quantify these constraints by placing the upper limit $λ_c = 3.0 d_H$ on the wavelength at which the power spectrum turns over to $k^4$ behavior. This means that sub-horizon processes can generate significant powe

J. Jesus Gonzalez, Javier Gorgas

Preliminary results based on a large compilation of line-strength profiles are presented and discussed. Elliptical galaxies (Es) with strong central Mg$_2$ show steeper line-strength gradients. These galaxies are more massive and have higher velocity dispersions, note nevertheless, that the Mg$_2$ gradient correlates better with central Mg$_2$ than with any

Sarah T. Maddison, James R. Murray, Joe J. Monaghan

We model a massless viscous disk using Smoothed Particle Hydrodynamics (SPH) and note that it evolves according to the Lynden-Bell \& Pringle theory (1974) until a non-axisymmetric instability develops at the inner edge of the disk. This instability may have the same origin as the instability of initially axisymmetric viscous disks discussed by Lyubarskij et

Koji Takahashi

The evolution of a spherical single-mass star cluster is followed in detail up to core collapse by numerically solving the orbit-averaged two-dimensional Fokker-Planck equation in energy-angular momentum space. Velocity anisotropy is allowed in the two-dimensional Fokker-Planck model. Using improved numerical codes, the evolution has been followed until the

Pavel Krtouš

The formalism of Ashtekar and Magnon \cite{AshtekarMagnon:1975} for the definition of particles in quantum field theory in curved spacetime is further developed. The relation between basic objects of this formalism (e.g., the complex structure) and different Green functions is found. It allows one to derive composition laws for Green functions. The relation

Leonid Positselski, Alexander Vishik

It it shown that the Bloch-Kato conjecture on the norm residue homomorphism $K^M(F)/l \to H^*(G_F,Z/l)$ follows from its (partially known) low-degree part under the assumption that the Milnor K-theory algebra $K^M(F)/l$ modulo $l$ is Koszul. This conclusion is a case of a general result on the cohomology of nilpotent (co-)algebras and Koszulity.

Martin J. Savage, Mark B. Wise

We analyze hyperon and nucleon mass shifts in nuclear matter using chiral perturbation theory. Expressions for the mass shifts that include strong interaction effects at leading order in the density are derived. Corrections to our results are suppressed by powers of the Fermi momentum divided by either the chiral symmetry breaking scale or the nucleon mass.

A. Kocic, J. B. Kogut

In a recent Letter we discussed the fact that large-$N$ expansions and computer simulations indicate that the universality class of the finite temperature chiral symmetry restoration transition in the 3D Gross-Neveu model is mean field theory. This was seen to be a counterexample to the standard &#39;sigma model&#39; scenario which predicts the 2D Ising mode

J. Gegelia, G. Japaridze, N. Kiknadze, K. Turashvili

A perturbative approach for non renormalizable theories is developed. It is shown that the introduction of an extra expansion parameter allows one to get rid of divergences and express physical quantities as series with finite coefficients. The method is demonstrated on the example of massive non abelian field coupled to a fermion field.

Adam F. Falk, Michael Luke, Martin J. Savage

We calculate the leading perturbative and power corrections to the hadronic invariant mass and energy spectra in semileptonic heavy hadron decays. We apply our results to the $B$ system. Moments of the invariant mass spectrum, which vanish in the parton model, probe gluon bremsstrahlung and nonperturbative effects. Combining our results with recent data on $

R. Kates, V. Müller, S. Gottlöber, J. P. Mücket

We have simulated the formation of large-scale structure arising from COBE-normalized spectra computed by convolving a primordial double-inflation perturbation spectrum with the CDM transfer function. Due to the broken scale invariance (&#39;BSI&#39;) characterizing the primordial perturbation spectrum, this model has less small-scale power than the (COBE-no

Ruth Durrer, Alejandro Gangui, Mairi Sakellariadou

The Doppler peaks (Sacharov peaks) in the angular power spectrum of the cosmic microwave background anisotropies, are mainly due to coherent oscillations in the baryon radiation plasma before recombination. Here we present a calculation of the Doppler peaks for perturbations induced by global textures and cold dark matter. We find that the height of the firs

Bruce M. Boghosian, Peter V. Coveney, Andrew N. Emerton

We develop a lattice gas model for the nonequilibrium dynamics of microemulsions. Our model is based on the immiscible lattice gas of Rothman and Keller, which we reformulate using a microscopic, particulate description so as to permit generalisation to more complicated interactions, and on the prescription of Chan and Liang for introducing such interparticl

Wolfgang Priester, Carsten van de Bruck

We present a new explanation for the very wide absorption features in quasar spectra. In our model, a very wide absorption feature will originate, when the line of sight crosses a bubble wall tangentially. We demonstrate this on the quasar pair (2138-4427), (2139-4434). Both show two very wide absorption lines in their spectra at the same redshift. The bubbl

S. Wycech, R. Smolanczuk

Nuclear interactions of antiprotons in atomic states are discussed. The total as well as partial widths for single nucleon capture events are calculated. These are compared to the X-ray and recent single nucleon capture data. The rates of the neutron or proton captures test nuclear density distributions at the extreme nuclear surface. Recently found cases of

G. Degrassi, S. Fanchiotti, F. Feruglio, P. Gambino

Theoretical uncertainties affecting electroweak observables are reviewed and the relevance of two-loop electroweak radiative corrections for the precision tests of the Standard Model is discussed.

Arif Akhundov, Dima Bardin, Lida Kalinovskaya, Tord Riemann

For the study of deep inelastic scattering at HERA, the use of Jaquet-Blondel variables is advantageous in several respects. We calculate the complete leptonic ${\cal O}(α)$ QED corrections for the reaction $ep \to eX$ in these variables. All but one phase space integrations are performed analytically. After exponentiation of soft photon corrections, an accu

Keith Slevin, Jean-Louis Pichard, P. A. Mello

We calculate the quantum correction to the classical conductance of a disordered mesoscopic normal-superconducting (NS) junction in which the electron spatial and spin degrees of freedom are coupled by an appreciable spin orbit interaction. We use random matrix theory to describe the scattering in the normal part of the junction and consider both quasi-balli

D. Bardin, M. Bilenky, A. Olchevski, T. Riemann

With a current-splitting technique, we calculate the gauge-invariant initial-state radiation to order \oalf\ with soft-photon exponentiation for on- and off-shell $W$-pair production. This result generalizes the convolution formula, which is known from the description of the $Z$ resonance, to the case of the production of two $W$-bosons. After up to eightfol

J. Santos, M. J. Reboucas, A. F. F. Teixeira

Three propositions about Jordan matrices are proved and applied to algebraically classify the Ricci tensor in n-dimensional Kaluza-Klein-type spacetimes. We show that the possible Segre types are [1,1...1], [21...1], [31\ldots 1], [z\bar{z}1...1] and degeneracies thereof. A set of canonical forms for the Segre types is obtained in terms of semi-null bases of

Don N. Page

The de Broglie-Bohm theory of quantum mechanics (here simply called Bohmian Mechanics or BM) [1-10] is an augmentation of ``bare&#39;&#39; quantum mechanics (the bare theory being given by an algebra of operators and a quantum state that sets the expectation values of these operators) that includes a definite history or Bohmian trajectory. This definite traj

H. Kleinert

For many physical quantities, theory supplies weak- and strong-coupling expansions of the types $\sum a_n α^n$ and $ α^p\sum b_n (α^{-2/q) ^n$, respectively. Either or both of these may have a zero radius of convergence. We present a simple interpolation algorithm which rapidly converges for an increasing number of known expansion coefficients. The accuracy

A. S. Wan, H. E. Dalhed, H. A. Scott, D. E. Post

An effective radiative divertor maximizes the utilization of atomic processes to spread out the energy deposition to the divertor chamber walls and to reduce the peak heat flux. Because the mixture of neutral atoms and ions in the divertor can be optically thick to a portion of radiated power, it is necessary to accurately model the magnitude and distributio

R. A. Vesey, D. E. Post, G. Bateman

To characterize the conditions required to reach advanced divertor regimes, a one-dimensional computational model has been developed based on a coordinate transformation to incorporate two-dimensional effects. This model includes transport of ions, two species each of atoms and molecules, momentum, and ion and electron energy both within and across the flux

M. Hedayati-Poor, J. I. Johansson, H. S. Sherif

The relativistic amplitude for the direct knock-out contribution to $\left( γ, p \right)$ reactions on nuclei is reduced to a nonrelativistic form using an effective Pauli reduction scheme. The reduction is carried out to second order in the inverse nucleon mass. It is found that the interaction Hamiltonian appearing in the nonrelativistic amplitude has sign

V. Dmitrašinović, Franz Gross

We establish a simple, explicit relation between the formalisms employed in the treatments of polarization observables in deuteron two-body electrodisintegration published by Arenhövel, Leidemann, and Tomusiak in Few-Body Systems {\bf 15}, 109 (1993) and the results of the present authors published in Phys.~Rev.~C {\bf 40}, 2479 (1989). We comment on the ove

W. Dieter Heiss, Rashid G. Nazmitdinov, Stefanel Radu

The effect of an axially symmetric hexadecapole term is investigated in a strongly deformed quadrupole potential. While the system is nonintegrable and shows significant chaotic behaviour classically, the quantum mechanical treatment not only produces a general smoothing effect with regard to chaos but even yields a pronounced shell structure at certain hexa

W. Dieter Heiss, Stefanel Radu

It is argued that, if a regular Hamiltonian is perturbed by a term that produces chaos, the onset of chaos is shifted towards larger values of the perturbation parameter if the unperturbed spectrum is degenerate and the lifting of the degeneracy is of second order in this parameter. The argument is based on the behaviour of the exceptional points of the full

H. Kuwabara, T. Hatsuda

$ϕ$-meson mass in nuclear matter ($m_ϕ^*$) is investigated using an effective Lagrangian of $ϕ$ interacting with octet baryons. $m_ϕ^*$ decreases by a few \% in nuclear matter due to the current conservation and effective nucleon/hyperon masses. Its implication to the p-A and A-A collisions are briefly discussed.

H. Kouno, K. Koide, T. Mitsumori, N. Noda

Compressional properties of nuclear matter are studied by using the mean field theory with the excluded volume effects of the nucleons. It is found that the excluded volume effects make it possible to fit the empirical data of the Coulomb coefficient $K_{c}$ of nucleus incompressibility, even if the volume coefficient $K$ is small($\sim 150$MeV). However, th

Siegfried Böcherer, Rainer Schulze-Pillot

We compute the central critical value of the triple product $L$-function associated to three cusp forms $f_1,f_2,f_3$ with trivial character for groups $Γ_0(N_i)$ with square free levels $N_i$ not all of which are $1$ and weights $k_i$ satisfying $k_1\ge k_2\ge k_3$ and $k_1<k_2+k_3$. This generalizes work of Gross and Kudla and gives an alternative classica

Sérgio Fenley, Lee Mosher

Any closed, oriented, hyperbolic three-manifold with nontrivial second homology has many quasigeodesic flows, where quasigeodesic means that flow lines are uniformly efficient in measuring distance in relative homotopy classes. The flows are pseudo-Anosov flows which are almost transverse to finite depth foliations in the manifold. The main tool is the use o

Omduth Coceal, Steven Thomas

We consider perturbations of the non-unitary minimal model solutions of two-dimensional conformal turbulence proposed by Polyakov. Demanding the absence of non-integrable singularities in the resulting theories leads to constraints on the dimension of the perturbing operator. We give some general solutions of these constraints, illustrating with examples of

Radhika Vathsan

The methods of reduced phase space quantization and Dirac quantization are examined in a simple gauge theory. A condition for the possible equivalence of the two methods is discussed.

R. M. Kashaev, N. Reshetikhin

The affine Toda field theory is studied as a 2+1-dimensional system. The third dimension appears as the discrete space dimension, corresponding to the simple roots in the $A_N$ affine root system, enumerated according to the cyclic order on the $A_N$ affine Dynkin diagram. We show that there exists a natural discretization of the affine Toda theory, where th

L. Girardello, A. Giveon, M. Porrati, A. Zaffaroni

Evidence in favor of $SL(2,Z)$ S-duality in $N=4$ supersymmetric Yang-Mills theories in four dimensions and with general compact, simple gauge groups is presented. (Contribution to the Proceedings of the Strings &#39;95 conference, March 13-18, 1995, USC, and the Proceedings of the Trieste Conference on S-Duality and Mirror Symmetry, June 5-9, 1995.)

A. Nyffeler, A. Schenk

For large values of the Higgs boson mass the low energy structure of the gauged linear sigma model in the spontaneously broken phase can adequately be described by an effective field theory. In this work we present a manifestly gauge invariant technique to explicitly evaluate the corresponding effective Lagrangian from the underlying theory. In order to demo

D. Indumathi, W. Zhu

The dynamical origins of the EMC effect are studied. We conclude that a swelling in size of a bound nucleon as well as nuclear binding plays an important rôle in determining the parton distributions within a bound nucleon. We find that the distortion of nucleon structure functions in nuclei can be simply explained with a few fundamental nuclear parameters.

A. I. Sanda, Atsushi Yamada

The differential decay width of the process $\bar{B} \rightarrow ρl \barν$ is related to that of the process $\bar{B} \rightarrow K^* l \lbar$ by using $SU(3)$-flavor symmetry and the heavy quark symmetry. The ratio of the Kobayashi-Maskawa matrix elements is obtained in the zero recoil limit of $ρ$ and $K^*$, allowing a determination of $|V_{ub}|$.

S. Dimopoulos, G. F. Giudice

In the absence of universality the naturalness upper limits on supersymmetric particle masses increase significantly. The superpartners of the two light generations can be much heavier than the weak scale without extreme fine-tunings; they can weigh up to about 900 GeV --- or even up to 5 TeV, if SU(5) universality is invoked. This supresses sparticle-mediat