June 1997 arXiv papers — page 11

Nikolai N. Nikolaev, B. G. Zakharov

The recent progress in the pQCD theroy of diffractive DIS (DDIS) is reviewed. We place emphasis on pQCD scales, diffractive factorization breaking, jet and charm production and new fundamental observables which are becomeing accessible with the Leading Proton Spectrometers of ZEUS and H1.

E. Bergshoeff, P. M. Cowdall, P. K. Townsend

The superfield equations of massive IIA supergravity, in the form of constraints on the superspace geometry, are shown to be implied by $κ$-symmetry of the topologically massive D-2-brane.

D0 Collaboration, B. Abbott et al

We report on a study of color coherence effects in ppbar collisions at a center of mass energy sqrt(s)=1.8 TeV. The data were collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. We observe the presence of initial-to-final state color interference with the spatial correlations between soft and hard jets in multijet event

D. V. Khveshchenko, Michael Reizer

We show that gapless plasmons lead to a universal $(δν(ε)/ν\propto |ε|/E_F)$ correction to the tunneling density of states of a clean two dimensional Coulomb interacting electron gas. We also discuss a counterpart of this effect in the "composite fermion metal" which forms in the presence of a quantizing perpendicular magnetic field corresponding to

B. Andreas, G. Curio

In this note we show that in dual N=1 string vacua provided by the heterotic string on an elliptic Calabi-Yau together with a vector bundle respectively F-theory on Calabi-Yau fourfold the number of heterotic fivebranes necessary for anomaly cancellation matches the number of F-theory threebranes necessary for tadpole cancellation. This extends to the genera

Holger F. Hofmann, Ortwin Hess

We investigate the effects of the electron-hole spin dynamics on the polarization fluctuations in the light emitted from a vertical cavity surface emitting laser (VCSEL). The Langevin equations are derived based on a rate equation model including birefringence, dichroism, and two carrier density pools seperately coupled to right and left circular polarizatio

I. Martin, A. Restuccia, R. Torrealba

We prove D=11 supermembrane theories wrapping around in an irreducible way over $S^{1} \times S^{1}\times M^{9}$ on the target manifold, have a hamiltonian with strict minima and without infinite dimensional valleys at the minima for the bosonic sector. The minima occur at monopole connections of an associated U(1) bundle over topologically non trivial Riema

N. Tetradis

We study the universal critical behaviour near weakly first-order phase transitions for a three-dimensional model of two coupled scalar fields -- the cubic anisotropy model. Renormalization-group techniques are employed within the formalism of the effective average action. We calculate the universal form of the coarse-grained free energy and deduce the ratio

T. Miyazaki, M. Troyer, M. Ogata, K. Ueda

The effects of non-magnetic impurities randomly doped into a two-leg Heisenberg spin ladder are investigated. Using the continuous time quantum Monte Carlo loop algorithm we calculate the uniform and staggered susceptibilities of such a system. The obtained uniform susceptibility is well described in terms of an effective model of weakly interacting local mo

Ryoji Enomoto, Masaharu Tanabashi

We consider $B^{\pm,0} \to ρ^0(ω)h^{\pm,0}$, where $ρ^0(ω)$ decays to $π^+π^-$ and $h$ is any hadronic final state, such as $π$ or $K$. We find a large direct CP asymmetry in B-meson decays via $ρω$ interference. A possible method to determine weak phases, such as $ϕ_{2,3}$, is discussed. The experimental feasibility is also shown.

Ivan Cherednik

We apply a new technique based on double affine Hecke algebras to the Harish-Chandra theory of spherical zonal functions. The formulas for the Fourier transforms of the multiplications by the coordinates are obtained as well as a simple proof of the Harish-Chandra inversion theorem using the Opdam transform.

Luca Salasnich

We study the energy fluctuations of a spatially homogeneous SU(2) Yang-Mills-Higgs system. In particular, we analyze the nearest-neighbour spacing distribution which shows a Wigner-Poisson transition by increasing the value of the Higgs field in the vacuum. This transition is a clear quantum signature of the classical chaos-order transition of the system.

Alfred Wünsche

The two-dimensional Radon transform of the Wigner quasiprobability is introduced in canonical form and the functions playing a role in its inversion are discussed. The transformation properties of this Radon transform with respect to displacement and squeezing of states are studied and it is shown that the last is equivalent to a symplectic transformation of

D. Palle

We show that the impact of the fundamental length in quantum mechanics can be studied within the formalism of Berry's geometrical phase with the line broadening as a resulting physical effect.

N. J. Cerf, C. Adami, P. G. Kwiat

A systematic method for simulating small-scale quantum circuits by use of linear optical devices is presented. It relies on the representation of several quantum bits by a single photon, and on the implementation of universal quantum gates using simple optical components (beam splitters, phase shifters, etc.). This suggests that the optical realization of sm

Haisheng Li

We give an analogue of the Hom functor and prove a generalized form of the nuclear democracy theorem of Tsuchiya and Kanie by using a notion of tensor product for two modules for a vertex operator algebra.

Kouichi Takemura

We decompose the level-1 irreducible highest weight modules of the quantum affine algebra $U_q(\hat{sl}_n)$ with respect to the level-0 $U'_q (\hat{sl}_n)$--action defined in q-alg/9702024. The decomposition is parameterized by the skew Young diagrams of the border strip type.

J. -L. Jestin, A. Kempf

It has been suggested that the minimization of the probability for lethal mutations is a major constraint shaping the genetic code, with the finding that the genetic code is highly protective against transition mutations. Here, we show that recent data on polymerase-induced frameshifts provide a rationale for the codon assignment of chain termination signals

Peter Lepage

These lectures illustrate the key ideas of modern renormalization theory and effective field theories in the context of simple nonrelativistic quantum mechanics and the Schrödinger equation. They also discuss problems in QED, QCD and nuclear physics for which rigorous potential models can be derived using renormalization techniques. They end with an analysis

Gerald A. Miller

A relativistic light front treatment of nuclei is developed by performing light front quantization for a chiral Lagrangian. The energy momentum tensor and the appropriate Hamiltonian are obtained. Three illustrations of the formalism are made. (1) Pion-nucleon scattering at tree level is shown to reproduce soft pion theorems. (2) The one boson exchange treat

F. Cano, P. Gonzalez, B. Desplanques, S. Noguera

Strong pionic decays of baryons are studied in a non-relativistic quark model framework via a convergent (p/E) expansion of the transition operator. Results are compared to the ones obtained within a more conventional (p/m) expansion.

A. De Silva, M. K. Moe, M. A. Nelson, M. A. Vient

The double beta decays of Mo-100 and Nd-150 were studied in a time projection chamber located 72 m underground. A 3275 h exposure of a 16.7 g sample of metallic Mo enriched to 97.4 % in Mo-100 resulted in a two-neutrino half-life of (6.82 + 0.38 - 0.53 +/- 0.68) * 10**18 y. Similarly, a 6287 h exposure of 15.5 g of Nd2O3 enriched to 91 % in Nd-150 yielded (6

Manuel Cepedello Boiso

We present here a new method for approximating functions defined on superreflexive Banach spaces by differentiable functions with $α$-Hölder derivatives (for some $0<α\leq 1$). The smooth approximation is given by means of an explicit formula enjoying good properties from the minimization point of view. For instance, for any function $f$ which is bounded bel

Carsten Butz, Ieke Moerdijk

For any first order theory T we construct a Boolean valued model M, in which precisely the T--provable formulas hold, and in which every (Boolean valued) subset which is invariant under all automorphisms of M is definable by a first order formula. Our presentation is entirely selfcontained, and only requires familiarity with the most elementary properties of

Edward Teo, Christopher Ting

Non-commutative differential geometry allows a scalar field to be regarded as a gauge connection, albeit on a discrete space. We explain how the underlying gauge principle corresponds to the independence of physics on the choice of vacuum state, should it be non-unique. A consequence is that Yang-Mills-Higgs theory can be reformulated as a generalised Yang-M

Diego Bellisai, Francesco Fucito, Marco Matone, Gabriele Travaglini

In this paper we first investigate the Ansatz of one of the present authors for K(Ψ,\barΨ), the adimensional modular invariant non-holomorphic correction to the Wilsonian effective Lagrangian of an N=2 globally supersymmetric gauge theory. The renormalisation group beta-function of the theory crucially allows us to express K(Ψ,\barΨ) in a form that easily ge

Stephen L. Adler

Recent work has shown that complex quantum field theory emerges as a statistical mechanical approximation to an underlying noncommutative operator dynamics based on a total trace action. In this dynamics, scale invariance of the trace action becomes the statement $0=Re Tr T_μ^μ$, with $T_{μν}$ the operator stress energy tensor, and with $Tr$ the trace over t

Philip C. Argyres

S-dualities in scale invariant N=2 supersymmetric field theories are derived by embedding those theories in asymptotically free N=2 theories with higher rank gauge groups. S-duality transformations on the coupling of the scale invariant theory follow from global symmetries acting on the Coulomb branch of the higher rank theory. Since these global symmetries

C. G. Torre

This is an introductory survey of the theory of $p$-form conservation laws in field theory. It is based upon a series of lectures given at the Second Mexican School on Gravitation and Mathematical Physics held in Tlaxcala, Mexico from December 1--7, 1996. Proceedings available online at http://kaluza.physik.uni-konstanz.de/2MS/ProcMain.html.

J. Rasmussen

In this paper free field realizations of affine current superalgebras are considered. Based on quantizing differential operator realizations of the corresponding basic Lie superalgebras, general and simple expressions for both the bosonic and the fermionic currents are provided. Screening currents of the first kind are also presented. Finally, explicit free

Tetsuji Miwa, Robert Weston

We consider the XXZ model in the infinite volume limit with spin half quantum space and higher spin auxiliary space. Using perturbation theory arguments, we relate the half infinite transfer matrices of this class of models to certain $U_q(\hat{sl_2})$ intertwiners introduced by Nakayashiki. We construct the monodromy matrices, and show that the one with spi

Hongsu Kim

Wormhole spacetimes may be responsible for the possible loss of quantum coherence and the introduction of additional fundamental quantum indeterminancy of the values of constants of nature. As a system which is known to admit such classical wormhole solutions, Einstein-Yang-Mills (EYM) theory is revisited. Since the classical wormhole instanton solution in t

Jose Bernabeu

These lectures cover different aspects of the subject of CP-Violation, from its description inside the Standard Model to the phenomenological analysis of the $K^0 - \bar{K}^0$ system and the prospects for its manifestation in B-physics.

M. Diehl, T. Gousset, B. Pire, J. P. Ralston

We discuss the handbag approximation to exclusive deep virtual Compton scattering. After defining the kinematical region where this approximation can be valid, we propose tests for its relevance in planned electroproduction experiments, e + p -> e + p + gamma. We focus on scaling laws in the cross section, and the distribution in the angle between the lepton

Helmut Satz

Contents: 1. The Thermodynamics of Quarks and Gluons 2. Hard Probes: Colour Deconfinement 3. Electromagnetic Probes: Chiral Symmetry Restoration 4. Soft Probes: Equilibration and Expansion 5. Conclusions

Eugene Levin

This talk is the second part of the summary of the theory section at DIS&#39;97. We demonstrated that theory of the &#34;hard&#34; processes, based on QCD, has achieved a better understanding of available experimental data during the past year. This was due to the remarkable success achieved in calculating of high order corrections in perturbative QCD (see t

W. Beenakker, A. P. Chapovsky, F. A. Berends

In this paper we study the non-factorizable QED corrections to W-pair-mediated (charged-current) four-fermion production in electron-positron collisions. A brief account of the obtained analytical results is given. They turn out to be different from the ones published in the literature. For the first time numerical results are presented, in particular the ef

M. Sachwitz, H. J. Schreiber, S. Shichanin

We discuss discovery potentials for a 140 GeV Standard Model Higgs boson produced in e+e- collisions at 360 GeV, including all potential irreducible and reducible background contributions. In the second part of the study, we estimate the uncertainties expected for the branching fractions of the Higgs into bb-bar, tau+tau-, WW* and into cc-bar+gg including a

C. R. Gattringer, I. Hip, C. B. Lang

Using the geometric definition of the topological charge we decompose the path integral of 2-dimensional U(1) lattice gauge theory into topological sectors. In a Monte Carlo simulation we compute the average value of the action as well as the distribution of its values for each sector separately. These numbers are compared with analytic lower bounds of the a

Rajendran Raja

We review the measurements of the top quark mass by the CDF and D-Zero collaborations using Run I data in excess of 100 inverse picobarns. The D-Zero collaboration has recently updated its measurement of the top quark mass in the lepton + jets channel. The world average of the top quark mass from the CDF and D-Zero measurements in the lepton + jets channel n

Shawn J. Kolitch, Douglas M. Eardley

This paper studies the decay of a large, closed domain wall in a closed universe. Such walls can form in the presence of a broken, discrete symmetry. We study a novel process of quantum decay for such a wall, in which the vacuum fluctuates from one discrete state to another throughout one half of the universe, so that the wall decays into pure field energy.

A. Chamblin, J. M. A. Ashbourn-Chamblin, R. Emparan, A. Sornborger

It has been argued that a black hole horizon can support the long range fields of a Nielsen-Olesen string, and that one can think of such a vortex as black hole ``hair''. We show that the fields inside the vortex are completely expelled from a charged black hole in the extreme limit (but not in the near extreme limit). This would seem to imply that a vortex

Eugene Lerman

We prove a criterion for stability of relative equilibria in symmetric Hamiltonian systems at singular points of the momentum map. This generalizes a theorem of G.W. Patrick. The method of the proof is also useful in studying the bifurcation of relative equilibria.

Igor Vilfan, Frederic Lancon, Jacques Villain

The structure of the $(\sqrt{31}\times \sqrt{31})R\pm9^\circ$ reconstructed phase on sapphire (0001) surface is investigated by means of a simulation based on the energy minimization. The interaction between Al adatoms is described with the semi-empirical many-body Sutton-Chen potential, corrected for the charge transfer between the metallic overlayer and th

Joel Ita, Ronald E. Cohen

The free energies of vacancy pair formation and migration in MgO were computed via molecular dynamics using free-energy integrations and a non-empirical ionic model with no adjustable parameters. The intrinsic diffusion constant for MgO was obtained at pressures from 0 to 140 GPa and temperatures from 1000 to 5000 K. Excellent agreement was found with the ze

Martin Albrecht, Beate Paulus, Hermann Stoll

Correlated ab-initio ground-state calculations, using relativistic energy-consistent pseudopotentials, are performed for six II-VI semiconductors. Valence ($ns,np$) correlations are evaluated using the coupled cluster approach with single and double excitations. An incremental scheme is applied based on correlation contributions of localized bond orbitals an

Fabio Siringo, Giovanni Piccitto

The energy level spacing distribution of a tight-binding hamiltonian is monitored across the mobility edge for a fixed disorder strength. Any mixing of extended and localized levels is avoided in the configurational averages, thus approaching the critical point very closely and with high energy resolution. By finite size scaling the method is shown to provid

R. Eder, Y. Ohta

We investigate the effect of a next-nearest neighbor hopping integral t&#39; in the 1D t-J model, using Lanczos diagonalization of finite chains. Surprisingly, even moderate values of t&#39; have a quite dramatic effect on the dynamical correlation functions and Fermi surface volume. The `holon&#39; becomes diffuse and overdamped, the band structure near the

T. Garel, H. Orland, E. Pitard

We present a statistical mechanics approach to the protein folding problem. We first review some of the basic properties of proteins, and introduce some physical models to describe their thermodynamics. These models rely on a random heteropolymeric description of these non random biomolecules. Various kinds of randomness are investigated, and the connection

Yasushi Honda, Tsuyoshi Horiguchi

We embody the density matrix renormalization group (DMRG) method for the 19-vertex model on a square lattice in order to investigate the Berezinskii-Kosterlitz-Thouless transition. Elements of the transfer matrix of the 19-vertex model are classified in terms of the total value of arrows in one layer of the square lattice. By using this classification, we su

Michael Baake, Uwe Grimm

The coordination sequence s(k) of a graph counts the number of its vertices which have distance k from a given vertex, where the distance between two vertices is defined as the minimal number of bonds in any path connecting them. For a large class of graphs, including in particular the classical root lattices, we present the coordination sequences and their

Abhijit Kar Gupta, Asok K. Sen

Study of various interesting features related to the nonlinear electrical response in composite materials through a model bond percolative system.

J. Roth

In a recent paper M. Dzugutov, Phys. Rev. Lett. 70 2924 (1993), describes a molecular dynamics cooling simulation where he obtained a large monatomic dodecagonal quasicrystal from a melt. The structure was stabilized by a special potential [Phys. Rev. A46 R2984 (1992)] designed to prevent the nucleation of simple dense crystal structures. In this comment we

Y. Morita, M. Kohmoto, K. Maki

A full quantum-mechanical treatment of the Bogoliubov-de Gennes equation for a single vortex in a d-wave superconductor is presented. First, we find low-energy states extended in four diagonal directions, which have no counterpart in a vortex of s-wave superconductors. The four-fold symmetry is due to &#39;quantum effect&#39;, which is enhanced when $p_{F}ξ$

W. Ebinger, J. Roth, H. -R. Trebin

Three-dimensional icosahedral random tilings with rhombohedral cells are studied in the semi-entropic model. We introduce a global energy measure defined by the variance of the quasilattice points in the orthogonal space. The internal energy, the specific heat, the configuration entropy and the sheet magnetization (as defined by Dotera and Steinhardt [Phys.R

W. Ebinger, J. Roth, H. -R. Trebin

Three-dimensional icosahedral random tilings are studied in the semi-entropic model. We introduce a global energy measure defined by the variance of the quasilattice points in orthogonal space. The specific heat shows a pronounced Schottky type anomaly, but it does not diverge with sample size. The flip susceptibility as defined by Dotera and Steinhardt [Phy

Johannes Roth, Reinhard Lück

The coincidence problem for three-dimensional discrete structures with icosahedral symmetry is reinvestigated. We present a parametric description of the coincidence rotations based on special quaternions, called icosian numbers. In particular, we give a characterization of the possible coincidence indices (Sigma-factors) and present a complete list of the p

M. Chertkov, I. Kolokolov, M. Vegrassola

Random advection of Lagrangian tracer scalar field $θ(t,x)$ by a one-dimensional, spatially smooth and short-correlated in time velocity field is considered. Scalar fluctuations are maintained by a source concentrated at the integral scale $L$. The statistical properties of both scalar differences and the dissipation field are analytically determined, exploi

M. Chertkov, I. Kolokolov, M. Vegrassola

A model of scalar turbulent advection in compressible flow is analytically investigated. It is shown that, depending on the dimensionality $d$ of space and the degree of compressibility of the smooth advecting velocity field, the cascade of the scalar is direct or inverse. If $d>4$, the cascade is always direct. For small enough degree of compressibility, th

C. W. Akerlof, S. Biller, P. Boyle, J. Buckley

A search was conducted for TeV gamma-rays emitted from the direction of the ultra-high energy cosmic ray detected by the Fly&#39;s Eye Experiment with E ~ 3 x 10**20 eV. No enhancement was found at a level of 10**-10 gamma/cm**2-sec for E>350 GeV. This upper limit is consistent with theoretical estimates based on topological defects as sources of UHE cosmic

F. Herwig, T. Blöcker, D. Schönberner, M. El Eid

The focus of this study is on the treatment of those stellar regions immediately adjacent to convective zones. The results of hydrodynamical simulations by Freytag et al. (1996, A&A313,497) show that the motion of convective elements extends well beyond the boundary of the convectively unstable region. We have applied their parametrized description of the co

Daniela Calzetti

The effects of dust opacity on the radiation of nearby and distant galaxies are reviewed. The geometrical distribution of the dust inside the galaxy plays a fundamental role in determining the wavelength dependence of the obscuration and the opacity of the galaxy. In the local Universe, late Hubble type galaxies appear to contain enough dust that corrections

Y. -Z. Qian, P. Vogel, G. J. Wasserburg

(Abridged) It is shown that a semi-quantitative agreement with the gross solar r-process abundance pattern near and above mass number A=130 can be obtained by a superposition of two distinctive kinds of supernova r-process events. These correspond to a low frequency case L and a high frequency case H, which takes into account the low abundance of I129 and th

Rosalba Perna, Abraham Loeb

Current microlensing searches calibrate the mass fraction of the Milky Way halo which is in the form of Massive Compact Halo Objects (MACHOs). We show that surveys like the Sloan Digital Sky Survey (SDSS) can probe the same quantity in halos of distant galaxies. Microlensing of background quasars by MACHOs in intervening galaxies would distort the equivalent

H. Brunner, C. Mueller, P. Friedrich, T. Doerrer

We present UV to soft X-ray spectra of 31 radio-quiet quasars, comprising data from the IUE ULDA database and the ROSAT pointed observation phase. 90 % of the sample members show a soft X-ray excess above an underlying hard X-ray power law spectrum. Particularly for the steep X-ray spectrum (alpha_energy > 1.5), low redshift subsample (17 objects) the X-ray

Henning Seemann, Peter L. Biermann

We use a luminous fast magnetic rotator model to analyze the influence of a magnetic field on the linear waves induced in the wind of a massive star by the radiative instability. We show that a twisted magnetic field can drive a strong wind with a wind efficiency $(\dot{M}v_\infty)/(L/c)>1$ even without multiple scattering. The radiation amplified waves in t

N. Cardiel, J. Gorgas, J. Cenarro, J. J. Gonzalez

We present a new set of accurate formulae for the computation of random errors in the measurement of atomic and molecular indices. The new expressions are in excellent agreement with numerical simulations. We have found that, in some cases, the use of approximated equations can give misleading line-strength index errors. It is important to note that accurate

R. G. Carlberg, S. L. Morris, H. K. C. Yee, E. Ellingson

The baryon density of the universe is equal to the product of the baryon-to-light ratio, M_b/L, and the luminosity density, j. We estimate M_b/L as the sum of the masses of the X-ray gas and the visible stars in a rich cluster of galaxies divided by the luminosity of the cluster galaxies in precisely the same sky aperture. We evaluate the gas-to-light ratio

H. Awata, S. Chaudhuri, M. Li, D. Minic

We show that the growth of the size with the number of partons holds in a Thomas-Fermi analysis of the threshold bound state of D0--branes. Our results sharpen the evidence that for a fixed value of the eleven dimensional radius the partonic velocities can be made arbitrarily small as one approaches the large N limit.

C. R. Stephens, J. C. Lopez Vieyra, A. Weber, P. O. Hess

The asymptotic behaviour of cubic field theories is investigated in the Regge limit using the techniques of environmentally friendly renormalization, environmentally friendly in the present context meaning asymmetric in its momentum dependence. In particular we consider the crossover between large and small energies at fixed momentum transfer for a model sca

Monica Tosi, Gary Steigman, Francesca Matteucci, Cristina Chiappini

Galactic destruction of primordial deuterium is inevitably linked through star formation to the chemical evolution of the Galaxy. The relatively high present gas content and low metallicity suggest only modest D-destruction. In concert with deuterium abundances derived from solar system and/or interstellar observations this suggests a primordial deuterium ab

Doug Beeferman, Adam Berger, John Lafferty

This paper introduces a new statistical approach to partitioning text automatically into coherent segments. Our approach enlists both short-range and long-range language models to help it sniff out likely sites of topic changes in text. To aid its search, the system consults a set of simple lexical hints it has learned to associate with the presence of bound

Ramesh Narayan, Rohan Mahadevan, Jonathan E. Grindlay, Robert G. Popham

Sgr A* at the Galactic Center is a puzzling source. It has a mass M=(2.5+/-0.4) x 10^6 solar masses which makes it an excellent black hole candidate. Observations of stellar winds and other gas flows in its vicinity suggest a mass accretion rate approximately few x 10^{-6} solar masses per year. However, such an accretion rate would imply a luminosity > 10^{

Eunsik Kim, D. L. Cox

We have studied the Knight shift $K(\vec r, T)$ and magnetic susceptibility $χ(T)$ of heavy electron materials, modeled by the infinite U Anderson model with the NCA method. A systematic study of $K(\vec r, T)$ and $χ(T)$ for different Kondo temperatures $T_0$ (which depends on the hybridization width $Γ$) shows a low temperature anomaly (nonlinear relation

A. Abbasabadi, D. Bowser-Chao, D. A. Dicus, W. W. Repko

We present cross sections for the reactions p pbar --> H gamma and pp --> Hγarising from the subprocess q qbar --> H gamma. The calculation includes the complete one-loop contribution from all light quarks as well as the tree contributions from light quarks and c and b quarks. These are the main sources of Higgs-photon associated production at hadron collide

B. W. Harris, J. Smith

A next-to-leading order Monte Carlo program for the calculation of heavy quark cross sections in deeply inelastic scattering is described. Concentrating on charm quark and D^*(2010) production at HERA, several distributions are presented and their variation with respect to charm quark mass, parton distribution set, and renormalization-factorization scale is

Zurab Tavartkiladze

We present an example of the gauge mediated SUSY breaking flipped SU(5) model. The messengers of the SUSY breaking are either only colour triplets which belong to the minimal content of the scalar supermultiplets or together with triplets as a messengers emerge the ordinary Higgs doublets. In both cases the model predicts light gauginos in respect of the squ

Lando Caiani, Lapo Casetti, Cecilia Clementi, Giulio Pettini

We perform a microcanonical study of classical lattice phi^4 field models in 3 dimensions with O(n) symmetries. The Hamiltonian flows associated to these systems that undergo a second order phase transition in the thermodynamic limit are here investigated. The microscopic Hamiltonian dynamics neatly reveals the presence of a phase transition through the time

A. B. van Oosten

Ab initio quantum chemical calculations of Heisenberg exchange in linear cuprate antiferromagnets are reported. For Sr2CuO3 I obtain Ja=-119 meV for the intrachain coupling and Jb=-0.28 meV for the interchain coupling. For Ca2CuO3 I find Ja=-119 meV and Jb=-0.52 meV. With these values, recent mean field theory gives the staggered magnetic moments as 0.069 an

Alex Krasnitz, Raju Venugopalan

We argue that the classical evolution of small x modes in the collision of two ultrarelativistic nuclei is described on a transverse lattice by the Kogut--Susskind Hamiltonian in 2+1-dimensions coupled to an adjoint scalar field. The initial conditions for the evolution are provided by the non--Abelian Weizsäcker--Williams fields which constitute the classic

Sergei V. Ketov

I attempt to analyse the next-to-leading-order non-holomorphic contribution to the Wilsonian low-energy effective action in the four-dimensional N=2 gauge theories with matter, from the manifestly N=2 supersymmeric point of view, by using the harmonic superspace. The perturbative one-loop correction is found to be in agreement with the N=1 superfield calcula

E. A. Ivanov, S. V. Ketov, B. M. Zupnik

We calculate the charged hypermultiplet low-energy effective action in the Coulomb branch of the 4D, N=2 gauge theory, by using the harmonic superspace approach. We find that the unique leading contribution is given by the harmonic-analytic Lagrangian of the fourth order in the hypermultiplet superfields, with the induced coupling constant being proportional

Giulio Casati, Giulio Maspero, Dima L. Shepelyansky

We show that the quantum relaxation process in a classically chaotic open dynamical system is characterized by a quantum relaxation time scale t_q. This scale is much shorter than the Heisenberg time and much larger than the Ehrenfest time: t_q ~ g^alpha where g is the conductance of the system and the exponent alpha is close to 1/2. As a result, quantum and

Joachim Hermisson, Uwe Grimm, Michael Baake

Some years ago, Luck proposed a relevance criterion for the effect of aperiodic disorder on the critical behaviour of ferromagnetic Ising systems. In this article, we show how Luck&#39;s criterion can be derived within an exact renormalisation scheme for Ising quantum chains with coupling constants modulated according to substitution rules. Luck&#39;s conjec

Subhendra Mohanty

We perform a covariant wave-packet analysis of neutrino oscillations taking into account the lifetime of the neutrino production process . We find that flavor oscillations in space are washed out when the neutrinos are produced from long lived resonances - and what may be observed in appearance/disappearance experiments is a uniform conversion probability in

S. V. Mikhailov

The contributions to non-singlet evolution kernels $P(z)$ for the DGLAP equation and $V(x,y)$ for the Brodsky-Lepage evolution equation are calculated for certain classes of diagrams which include the renormalon chains. Closed expressions are obtained for the sums of contributions associated with these diagram classes. Calculations are performed in the $[ϕ^3

Dongsheng Du Hongying Jin Yadong Yang

We discuss the nonfactorization effects in $B\to J/Ψ+X_{s}$, which is similar to the nonperturbative effect found by Voloshin in the decay $B\to γ+X_{s}$. The QCD sum rule has been used to estimate the hadron matrix elements. We find that the correction from this effect is very large and the large discrepancy between the theory and the experimental data can

Paolo Tomassini

We take advantage of peculiar properties of three dimensional incompressible turbulence to introduce a nonstandard Exact Renormalization Group method. A Galilean invariance preserving regularizing procedure is utilized and a field truncation is adopted to test the method. Results are encouraging: the energy spectrum E(k) in the inertial range scales with exp

G. Cvetic, C. S. Kim, S. S. Hwang

We derive one-loop renormalization group equations (RGE&#39;s) for Yukawa coupling parameters of quarks and for the vacuum expectation values of the Higgs doublets in a general framework of the Standard Model with two Higgs doublets (2HDM ``type III&#39;&#39;). In the model, the neutral-Higgs-mediated flavor-changing neutral currents are allowed but are assu

Stefan Boettcher

In a recent Letter [Phys. Rev. Lett. 79, 889 (1997) and cond-mat/9702054] we have demonstrated that the avalanches in the Bak-Sneppen model display aging behavior similar to glassy systems. Numerical results for temporal correlations show a broad distribution with two distinct regimes separated by a time scale which is related to the age of the avalanche. Th

Dong-Sheng Du, Mao-Zhi Yang

In this work we study the CP violation for $\bar{B^0}\to J/ψK_s$ and $\bar{B^0}\to ϕK_s$ up to leading and next-to-leading order QCD corrections in the standard model, two-Higgs-doublet model and the minimal supersymmetric extension of the standard model. We also study the effect of new physics on the branching ratios of these two decay modes. We find that w

C. H. Oh, K. Singh

The recent focus on deformations of algebras called quantum algebras can be attributed to the fact that they appear to be the basic algebraic structures underlying an amazingly diverse set of physical situations. To date many interesting features of these algebras have been found and they are now known to belong to a class of algebras called Hopf algebras [1

D. Hoffmann, E. W. Knapp

A small model polypeptide represented in atomic detail is folded using Monte Carlo dynamics. The polypeptide is designed to have a native conformation similar to the central part of the helix-turn-helix protein ROP. Starting from a beta-strand conformation or two different loop conformations of the protein glutamine synthetase, six trajectories are generated

J. M. Aguirregabiria, A. Hernández, M. Rivas

We discuss the phenomenon of preacceleration in the light of a method of successive approximations used to construct the physical order reduction of a large class of singular equations. A simple but illustrative physical example is analyzed to get more insight into the convergence properties of the method.

Lajos Molnar

The aim of this note is to show that the automorphism and isometry groups of the C*-algebra $ł_\infty(N,B(H))$ of all bounded sequences in $B(H)$ are topologically reflexive which, as one of our former results shows, is not the case with the &#34;scalar algebra&#34; $l_\infty$.

Yehoram Gordon, Marius Junge, Niels Jorgen Nielsen

In this paper we investigate a property named GL(p,q) which is closely related to the Gordon-Lewis property. Our results on GL(p,q) are then used to estimate volume ratios relative to $\ell_p$, $1<p \le\infty$, of unconditional direct sums of Banach spaces.

Ralf Schindler

Suppose that there&#39;s no transitive model of ZFC + there&#39;s a strong cardinal, and let K denote the core model. It is shown that if δhas the tree property then δ^{+K} = δ^+ and δis weakly compact in K.

Jyh-Hao Lee, Oktay K. Pashaev

We show that the one-dimensional projection of Chern-Simons gauged Nonlinear Schrodinger model is equivalent to an Abelian gauge field theory of continuum Heisenberg spin chain. In such a theory, the matter field has geometrical meaning of coordinates in tangent plane to the spin phase space, while the U(1) gauge symmetry relates to rotation in the plane. Th

Kazunori Itakura

We investigate how the gap equations are obtained in the light-front formalism within the four-Fermi theories. Instead of the zero-mode constraint, we find that the &#34;fermionic constraints&#34; on nondynamical spinor components are responsible for symmetry breaking. Careful treatment of the infrared divergence is indispensable for obtaining the gap equati

Seiji Terashima, Sung-Kil Yang

We obtain a low-energy effective superpotential for a phase with a single confined photon in N=1 gauge theory with an adjoint matter with ADE gauge groups. The expectation values of gauge invariants built out of the adjoint field parametrize the singularities of moduli space of the Coulomb phase. The result can be used to derive the N=2 curve in the form of