June 1996 arXiv papers — page 13

Franz-Josef Elmer

We study parametric resonance of interacting waves having the same wave vector and frequency. In addition to the well-known period-doubling instability we show that under certain conditions the instability is caused by a Hopf bifurcation leading to quasiperiodic traveling waves. It occurs, for example, if the group velocities of both waves have different sig

C. A. Bertulani, V. Yu. Ponomarev, V. V. Voronov

The electromagnetic excitation of the two-phonon isovector giant dipole resonance in relativistic projectiles incident on heavy targets can be proceed via several intermediate $1^-$ one-phonon giant resonance states. In two step electric dipole transitions the population of $0^+$, $1^+$, and $2^+ $ two-phonon states are possible. We calculate the amplitude d

John F. Dubach, Geoffrey B. Feldman, Barry R. Holstein, Lorenzo de la Torre

The weak nonmesonic decay of Lambda-hypernuclei is studied in the context of a one-meson-exchange model. Predictions are made for the decay rate, p/n stimulation ratio and the asymmetry in polarized hypernuclear decay.

Yang Lu, R. D. Amado

We calculate the nucleon-antinucleon static potential in the Skyrme model using the product ansatz and including some finite $N_C$ (number of colors) corrections. The mid and long range part of the spin-spin and tensor force are correctly given in both iso-spin channels while the central interaction has insufficient mid-range attraction. This is a well known

A. V. Isaev, S. G. Krantz

For a smoothly bounded pseudoconvex domain $D\subset{\Bbb C}^n$ of finite type with non-compact holomorphic automorphism group $\text{Aut}(D)$, we show that the set $S(D)$ of all boundary accumulation points for $\text{Aut}(D)$ is a compact subset of $\partial D$ and, if $S(D)$ contains at least three points, it is connected and thus has the power of the con

O. V. Tarasov

A systematic algorithm for obtaining recurrence relations for dimensionally regularized Feynman integrals w.r.t. the space-time dimension $d$ is proposed. The relation between $d$ and $d-2$ dimensional integrals is given in terms of a differential operator for which an explicit formula can be obtained for each Feynman diagram. We show how the method works fo

P. Bowcock, R-L. K. Koktava, A. Taormina

Free field representations of the affine superalgebra $A(1,0)^{(1)}$ at level $k$ are needed in the description of the noncritical $N=2$ string. The superalgebra admits two inequivalent choices of simple roots. We give the Wakimoto representations corresponding to each of these and derive the relation between the two at the quantum level.

F. Barbarin, E. Ragoucy, P. Sorba

The property of some finite W-algebras to appear as the commutant of a particular subalgebra in a simple Lie algebra G is exploited for the obtention of new G-realizations from a "canonical" differential one. The method is applied to the conformal algebra so(4,2) and therefore yields also results for its Poincare subalgebra. Unitary irreducible repre

A. A. Zheltukhin

A perturbation theory with respect to tension parameter $γ/α^\prime$ for the non--linear equations of string, moving in curved space--time is considered. Obtained are linearized motion equations for the functions of the $n-$th degree of approximation ($n=0,1,2$)

Hitoshi Konno

The trigonometric Ruijsenaars-Schneider model is diagonalized by means of the Macdonald symmetric functions. We evaluate the dynamical density-density correlation function and the one-particle retarded Green function as well as their thermodynamic limit. Based on these results and finite-size scaling analysis, we show that the low-energy behavior of the mode

T. D. Palev, N. I. Stoilova

We present examples of many-body Wigner quantum systems. The position and the momentum operators ${\bf R}_A$ and ${\bf P}_A,\; A=1,\ldots,n+1$, of the particles are noncanonical and are chosen so that the Heisenberg and the Hamiltonian equations are identical. The spectrum of the energy with respect to the centre of mass is equidistant and has finite number

A. H. Chamseddine

Type II superstring theory with mixed Dirichlet and Neumann boundary conditions admit antisymmetric tensors with varying degrees in the spectrum. We show that there exists a family of dual supergravity lagrangians to the $N=2$ type IIA action in ten dimensions. The duality transformations and the resulting actions are constructed explicitely.

O. V. Tarasov

We present a new method for the momentum expansion of Feynman integrals with arbitrary masses and any number of loops and external momenta. By using the parametric representation we derive a generating function for the coefficients of the small momentum expansion of an arbitrary diagram. The method is applicable for the expansion w.r.t. all or a subset of ex

J. A. Casas, S. Dimopoulos

The stability of the standard vacuum imposes constraints on flavor violating trilinear soft terms which are stronger than the laboratory bounds coming from the absence of neutral flavor violations (FCNC). Furthermore, contrary to the FCNC bounds, these constraints persist even if the scale of supersymmetry breaking is arbitrarily large.

N. G. Deshpande, Sechul Oh

We propose two independent methods to determine the CKM phase $γ$ and the tree and penguin amplitudes using neutral $B$ decays, assuming that the phase $β$ is known. Based on flavor SU(3) symmetry and SU(3) breaking effect, one method uses the decay processes $B^0(t) \rightarrow π^0 K_S$, $B^0 \rightarrow ηK^0 \; (K_S \rightarrow ππ)$ and their charge-conjug

M. Suzuki

Evolution of disoriented chiral condenstates is studied with the classical sigma model in 3+1 dimensions. By smoothly connecting a chiral symmetric solution of the formation period to a solution of the decay period, we obtain a complete spacetime evolution of the pion field for a simple and physically interesting source. The formation process is discussed qu

R. S. Chivukula, J. Terning

Using precision electroweak data, we put limits on ``natural'' top-color assisted technicolor models. Generically the new $U(1)$ gauge bosons in these models must have masses larger than roughly 2 TeV, although in certain (seemingly unrealistic) models the bound can be much lower.

T. Han, K. Whisnant, B. -L. Young, X. Zhang

We examine the experimental observability of the decay mode $t \rightarrow c g$ at the Fermilab Tevatron via the flavor-changing neutral current vertex $t \bar c g$. We find that with the existing data, one should be able to probe the $t \bar c g$ coupling to a value smaller than indirect limits previously obtained from $b\rightarrow s γ$ and the measured br

Peter Cho, Adam K. Leibovich

We calculate in closed form the complete ${\mathcal O}(α_s^2)$ color-singlet differential cross section for $e^+e^- \to γ^* \to ψ_Q+X$ scattering. The cross section reduces at high energies to a heavy quark fragmentation form. We find that the energy scale at which the approximate fragmentation result becomes reliable exceeds the $ψ_Q$ mass by more than an o

Barry R. Holstein

The present status of low energy test of chiral invariance via chiral perturbation theory is reviewed, both in the meson and baryon sectors, and future prospects are discussed.

G. Conforto, A. Marchionni, F. Martelli, F. Vetrano

Deviations from expectations have been claimed for solar, atmospheric and high energy prompt neutrinos from charm decay. This information, supplemented only by the existing very good upper limits for oscillations of the $ν_μ$ at accelerator energies, is used as input to a phenomenological three-flavour analysis of neutrino mixing. The solution found is uniqu

Mauro Moretti

I present a systematic study of all possible four leptons final states from $γγ$ collisions. It is given a detailed account of fermion masses effects which are sizable since several collinear and $t$ channel enancements occur. The effects of angular cuts on the final charged leptons are also discussed. To perform the computation I have used the recently deve

A. V. Sidorov, D. B. Stamenov

The results of LO {\it Fixed point} QCD (FP-QCD) analysis of the CCFR data for the nucleon structure function $~xF_3(x,Q^2)~$ are presented. The predictions of FP-QCD, in which the Callan-Symanzik $~β~$ function admits a {\it second order} ultraviolet zero at $~α= α_0~$ are in good agreement with the data. Constraints for the possible values of the $~β~$ fun

Aneesh V. Manohar

These lectures introduce some of the basic ideas of effective field theories. The topics discussed include: relevant and irrelevant operators and scaling, renormalization in effective field theories, decoupling of heavy particles, power counting, and naive dimensional analysis. Effective Lagrangians are used to study the $ΔS=2$ weak interactions and chiral p

Nobuchika Okada

Recently, it was pointed out that the solar and atmospheric neutrino deficits can be explained by oscillations between electroweak doublet and singlet neutrinos in the model of Majorana neutrinos. However, since the model includes no flavor mixing, it cannot explain the recent LSND result. We extend the model to include the flavor mixing, and obtain the expl

P. Colangelo, F. De Fazio, G. Nardulli

A QCD relativistic potential model is employed to compute the decay rate and the photon spectrum of the process $B^- \to μ^- {\bar ν}_μγ$. The result ${\cal B}(B^- \to μ^- {\bar ν}_μγ) \simeq 1 \times 10^{-6}$ confirms the enhancement of this decay channel with respect to the purely leptonic mode, and supports the proposal of using this process to access rel

K. S. Babu, Jogesh C. Pati

The commonly accepted notion of a weak unified coupling $α_X \approx 0.04$, based on the assumption of the MSSM--spectrum, is questioned. It is suggested that the four--dimensional unified string coupling should very likely have an intermediate value $(\sim 0.2-0.3$, say) so that it may be large enough to stabilize the dilaton but not so large as to disturb

P. Maris

We investigate the influence of the full vacuum polarization and vertex function on the fermion propagator, using the coupled Dyson--Schwinger equations for the photon and fermion propagator. We show that, within a range of vertex functions, the general behavior of the fermion propagator does not depend on the exact details of the vertex, both in the massles

Michael Dittmar

The possibilities to measure lepton forward--backward asymmetries at the LHC in the reaction pp(qqbar) --> l+l- are studied for dilepton events with masses above 400 GeV. It is shown that such measurements allow accurate tests of the neutral current interference structure up to about 2 TeV center of mass energies. The sensitivity of asymmetries at the LHC to

Hitoshi Murayama

The need to understand physics of electroweak symmetry breaking is reviewed. An electron positron linear collider will play crucial roles in that respect. It is discussed how the LHC and a linear collider need each other to understand symmetry breaking mechanism unambiguously. Two popular scenarios, supersymmetry and technicolor-like models, are used to demo

K. S. Virbhadra

We consider a static, axially symmetric, and asymptotically flat exact solution of the Einstein vacuum equations, known as the gamma metric. This is characterized by two constant parameters $m$ and $γ$. We find that the total energy associated with this metric is $m γ$. Considering the total energy to be positive, we investigate the nature of a curvature sin

W. Krivan, P. Laguna, P. Papadopoulos

A numerical study of the evolution of a massless scalar field in the background of rotating black holes is presented. First, solutions to the wave equation are obtained for slowly rotating black holes. In this approximation, the background geometry is treated as a perturbed Schwarzschild spacetime with the angular momentum per unit mass playing the role of a

Alexander L. Fetter

The Bogoliubov approximation is used to study the excited states of a dilute gas of $N$ atomic bosons trapped in an isotropic harmonic potential characterized by a frequency $ω_0$ and an oscillator length $d_0 = \sqrt{\hbar/mω_0}$. The self-consistent static Bose condensate has macroscopic occupation number $N_0 \gg 1$, with nonuniform spherical condensate d

Victor Matveev, Robert Shrock

We determine the exact complex-temperature (CT) phase diagram of the 1D $Z_6$ clock model. This is of interest because it is the first exactly solved system with a CT phase boundary exhibiting a finite-$K$ intersection point where an odd number of curves (namely, three) meet, and yields a deeper insight into this phenomenon. Such intersection points occur in

Jysoo Lee

Using numerical and analytic methods, we study the time dependent behavior of granular material in a vibrating box. We find, by molecular dynamics simulation, that the temporal fluctuations of the pressure and the height expansion scale in $A f$, where $A$ ($f$) is the amplitude (frequency) of the vibration. On the other hand, the fluctuations of the velocit

Gang Su

By using the so-called matrix-product ground state approach, a few one-dimensional quantum systems, including a frustrated spin-1/2 Heisenberg ladder, the ferromagnetic t-J-V model at half-filling, the antiferromagnetic $J_z-V$ at 2/3 filling and the antiferromagnetic $t-J_z-V$ model at half-filling, are solved exactly. The correlation functions in the groun

Takao Morinari, Naoto Nagaosa

Edge modes are studied for the hierarchical fractional quantum Hall liquids (FQHL) by treating the edge and bulk in a unified fashion. Within the RPA treatment of the composite boson effective theory with Coulomb interaction, one edge magneto-plasmon is shown to be the eigen-mode of the system. This mode decays algebraically perpendicular to the edge. All th

R. Chaudhury, D. Gangopadhyay, S. K. Paul

We find a non-invertible matrix representation for Van der Waerden's colouring theorem for two distinct colours in a one dimensional periodic lattice. Using this,an infinite one dimensional antiferromagnetic Ising system is mapped to a pseudo-ferromagnetic one, thereby relating the couplings. All this is reminiscent of renormalisation group.

Bernd Ludwig

This paper presents the results of an experiment to decide the question of authenticity of the supposedly spurious Rhesus - a attic tragedy sometimes credited to Euripides. The experiment involves use of statistics in order to test whether significant deviations in the distribution of word categories between Rhesus and the other works of Euripides can or can

Marc Light

Increasingly, inheritance hierarchies are being used to reduce redundancy in natural language processing lexicons. Systems that utilize inheritance hierarchies need to be able to insert words under the optimal set of classes in these hierarchies. In this paper, we formalize this problem for feature-based default inheritance hierarchies. Since the problem tur

Marc Light

Most natural language processing tasks require lexical semantic information. Automated acquisition of this information would thus increase the robustness and portability of NLP systems. This paper describes an acquisition method which makes use of fixed correspondences between derivational affixes and lexical semantic information. One advantage of this metho

J. P. Ueberla, I. R. Gransden

In this paper, a hierarchical context definition is added to an existing clustering algorithm in order to increase its robustness. The resulting algorithm, which clusters contexts and events separately, is used to experiment with different ways of defining the context a language model takes into account. The contexts range from standard bigram and trigram co

K. Harigaya

Charge-transfer (CT) exciton effects are investigated for the optical absorption spectra of crosslinked C60 systems by using the intermediate exciton theory. We consider the C60-dimers, and the two (and three) molecule systems of the C60-polymers. We use a tight-binding model with long-range Coulomb interactions among electrons, and the model is treated by t

D. L. Jones, S. J. Tingay, D. W. Murphy, D. L. Meier

A sub-parsec scale radio counterjet has been detected in the nucleus of the closest radio galaxy, Centaurus A (NGC 5128), with VLBI imaging at 2.3 and 8.4 GHz. This is one of the first detections of a VLBI counterjet and provides new constraints on the kinematics of the radio jets emerging from the nucleus of Cen A. A bright, compact core is seen at 8.4 GHz,

S. A. Pustilnik, V. A. Lipovetsky, Yu. I. Izotov, E. Brinks

The Blue Compact Dwarf (BCD) galaxy SBS 0335--052 is one of the most metal--deficient galaxies known and one of the best candidates for a young dwarf galaxy in the process of formation. A VLA HI map reveals an unusual structure: the neutral gas is distributed in a very extended disk, about 15 times larger than the Holmberg optical diameter of the BCG. There

R. J. Lavery, P. Seitzer, N. B. Suntzeff, A. R. Walker

Hubble Space Telescope WFPC2 images of the Local Group dwarf galaxy Tucana reveal an unbiased sample of distant field galaxies. While a large number of these galaxies can be classified according to standard Hubble types, a significant number of these galaxies can be identified as "ring" galaxies, a morphology likely induced through galaxy collisions.

Vahe Petrosian, Theodore T. Lee

In the use and interpretation of $\log{N}$--$\log{S}$ distributions for gamma-ray bursts, burst peak flux has typically been used for $S$. We consider here the use of the fluence as a measure of $S$, which may be a more appropriate quantity than the peak flux in such highly variable sources. We demonstrate how using the BATSE trigger data we can determine th

Mikel Susperregi

In the context of Brans--Dicke theories, eternal inflation is described in such a way that the evolution of the inflaton field is determined by the value of the Planck mass in different regions of the universe. The Planck mass is given by the values of the Brans--Dicke field, which is coupled to the scalar curvature in the Lagrangian. We first calculate the

Guy Worthey, Ben Dorman, Lewis Jones

Stellar population models with abundance distributions determined from the analytic Simple model of chemical evolution fail to match observations of the nuclei of bulge-dominated galaxies in three respects. First, the spectral energy distribution in the mid-ultraviolet range 2000 < lam < 2400 exceeds observation by ~ 0.6 mag. Most of that excess is due to me

Luis C. Ho

Recent high-resolution observations with the Hubble Space Telescope (HST) reveal that young star clusters of extraordinary luminosity and compactness (&#34;super star clusters&#34;) are commonly found in starburst systems. Cluster formation appears to be a dominant mode of star formation in starbursts. The principal properties of the young clusters are summa

T. M. D. Ebbels, J. -F. Le Borgne, R. Pelló, R. S. Ellis

We discuss the optical spectrum of a multiply-imaged arc resolved by HST in the $z$=0.175 cluster A2218. The spectrum, obtained with LDSS-2 on the 4.2m William Herschel telescope, reveals the source to be a galaxy at a redshift $z$=2.515 in excellent agreement with the value predicted by Kneib et al. (1996) on the basis of their inversion of a highly-constra

A. Mastichiadis, O. C. de Jager

Supernova 1006 is the first shell type supernova remnant to show evidence of particle acceleration to TeV energies. In the present paper we examine this possibility by modeling the observed X-ray non-thermal emission in terms of synchrotron radiation from Fermi accelerated electrons. The predicted synchrotron spectrum fits the radio and non-thermal component

P. Andreani, A. Franceschini

We present 1.25 mm continuum data for a southern galaxy sample selected from the IRAS PSC and complete to S_60=2 Jy. Two thirds of the galaxies have been detected and significant limits on the remaining objects have been set. We find, on a statistical basis, indications that the dust emission in these galaxies is somewhat more centrally concentrated than tha

D. P. Bennett, C. Alcock, R. A. Allsman, D. Alves

The MACHO collaboration has recently analyzed 2.1 years of photometric data for about 8.5 million stars in the Large Magellanic Cloud (LMC). This analysis has revealed 8 candidate microlensing events and a total microlensing optical depth of $τ_{meas} = 2.9 +1.4/-0.9 \times 10^{-7}$. This significantly exceeds the number of events (1.1) and the microlensing

Hannu Kurki-Suonio, Karsten Jedamzik, Grant J. Mathews

We examine effects on primordial nucleosynthesis from a truly random spatial distribution in the baryon-to-photon ratio ($η$). We generate stochastic fluctuation spectra characterized by different spectral indices and root-mean-square fluctuation amplitudes. For the first time we explicitly calculate the effects of baryon diffusion on the nucleosynthesis yie

Xingming Chen, Ronald E. Taam

A framework for the interpretation of the spectral states of black hole X-ray transients based on the diversity of accretion disk models is introduced. Depending on the mass accretion rate, it is proposed that the accretion disk is described by one or a combination of the following structures: optically thick disk, advection-dominated disk, corona-disk, and

Jason A. Taylor

Previous works concerning active galactic nuclei (AGN) variability (e.g., Blandford \& McKee 1982) have assumed that the emission characteristics of illuminated clouds are purely a function of the instant continuum flux to which they are exposed. This paper shows that this assumption is not necessarily justified and that the history of exposure accounting fo

Vladimir Sadov

We derive the anomaly 8-form of 6-dimensional gauge theories arising in F theory compactifications on elliptic Calabi-Yau threefolds. The result allows to determine the matter content of certain such theories in terms of intersection numbers on the base of elliptic fibration. We also discuss gauge theories on 7-branes with double point singularities on the w

Dave Allen, David Senechal

We study the spin-1/2 chain with nearest neighbor ($κ_1$) and next-nearest neighbor ($κ_2$) interactions in the regime $κ_2\gg κ_1$, which is equivalent to two chains with a `zig-zag&#39; interaction. In the continuum limit, this system is described in term of two coupled level-1 WZW field theories. We illustrate its equivalence with four off-critical Ising

Jan Govaerts

Recently, within the context of the phase space coherent state path integral quantisation of constrained systems, John Klauder introduced a reproducing kernel for gauge invariant physical states, which involves a projection operator onto the reduced Hilbert space of physical states, avoids any gauge fixing conditions, and leads to a specific measure for the

D. Boyanovsky, R. Holman, S. Prem Kumar

We study the decay of scalar fields, in particular the inflaton, into lighter scalars in a De Sitter spacetime background. After providing a practical definition of the rate, we focus on the case of an inflaton interacting with a massless scalar field either minimally or conformally coupled to the curvature. The evolution equation for the expectation value o

Erik Sorensen, Allan MacDonald

We consider the localization of independent electron orbitals in double-layer two-dimensional electron systems in the strong magnetic field limit. Our study is based on numerical Thouless number calculations for realistic microscopic models and on transfer matrix calculations for phenomenological network models. The microscopic calculations indicate a crosso

Andrew Toon

It is argued that quantum gravity has an interpretation as a topological field theory provided a certain constraint from the path intergral measure is respected. The constraint forces us to couple gauge and matter fields to gravity for space - time dimensions different from 3. We then discuss possible models which may be relevant to our universe.

Bernard Derrida, Vincent Hakim, Reuven Zeitak

The fraction r(t) of spins which have never flipped up to time t is studied within a linear diffusion approximation to phase ordering. Numerical simulations show that, even in this simple context, r(t) decays with time like a power-law with a non-trival exponent $θ$ which depends on the space dimension. The local dynamics at a given point is a special case o

G. Akemann

An iterative scheme is set up for solving the loop equation of the hermitian one-matrix model with a multi-cut structure. Explicit results are presented for genus one for an arbitrary but finite number of cuts. Due to the complicated form of the boundary conditions, the loop correlators now contain elliptic integrals. This demonstrates the existence of new u

P. Andreani, A. Franceschini

We have studied the FIR/{\it mm} spectrum of IR galaxies by combining IRAS photometry with new {\it mm} data on a complete southern IRAS galaxy sample. The observed spectra and a dust model emphasize a dicothomy in the galaxy population: half of the objects with a lot of warm dust are characterized by higher values of the bolometric (UV-FIR) luminosity, of t

Changrim Ahn, Wai Ming Koo

We compute the boundary scattering amplitudes of the breathers of the supersymmetric sine-Gordon model using the fusion of the soliton-antisoliton pair scattering with the boundary with a known result of the soliton boundary scattering amplitudes. We also solve the boundary Yang-Baxter equation of the eight-vertex free fermion models to find the boundary ref

H. Kleinert

This conference talk elaborates on a recently discovered mapping procedure by which classical orbits and path integrals for the motion of a point particle in flat space can be transformed correctly into those in curved space. This procedure evolved from well established methods in the theory of plastic deformations where crystals with defects are described m

Felix M. Lev

We consider restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group and show that the nonperturbative part of the current operator contributes to deep inelastic scattering even in leading order in $1/Q$ where $Q$ is the magnitude of the momentum transfer. Some

Avinash Dhar, Gautam Mandal, Spenta R. Wadia

Classically a black hole can absorb but not emit energy. We discuss how this T-asymmetric property of black holes arises in the recently proposed (T-symmetric) microscopic models of black holes based on bound states of D-branes. In these string theory based models, the nonvanishing classical absorption is made possible essentially by the exponentially increa

Mitsuko Abe

We derive the partition functions of the Schwarz-type four-dimensional topological half-flat 2-form gravity model on K3-surface or T^4 up to on-shell one-loop corrections. In this model the bosonic moduli spaces describe an equivalent class of a trio of the Einstein-Kähler forms (the hyperkähler forms). The integrand of the partition function is represented

Ramesh Narayan, Matthias Bartelmann

These lectures give an introduction to Gravitational Lensing. We discuss lensing by point masses, lensing by galaxies, and lensing by clusters and larger-scale structures in the Universe. The relevant theory is developed and applications to astrophysical problems are discussed.

Boris Chibisov, R. David Dikeman, M. Shifman, N. G. Uraltsev

The quark (gluon)-hadron duality constitutes a basis for the theoretical treatment of a wide range of inclusive processes -- from hadronic τdecays and R_{e^+e^-}, to semileptonic and nonleptonic decay rates of heavy flavor hadrons. A theoretical analysis of these processes is carried out by using the operator product expansion in the Euclidean domain, with s

J. F. Cornwell

The defining conditions for the irreducible tensor operators associated with the unitary irreducible corepresentions of compact quantum group algebras are deduced first in both the right and left regular coaction formalisms. In each case it is shown that there are {\em{two}} types of irreducible tensor operator, which may be called `ordinary&#39; and `twiste

A. G. Rossberg, A. Hertrich, L. Kramer, W. Pesch

Quasi two-dimensional pattern forming systems with spontaneously broken isotropy represent a novel symmetry class, that is experimentally accessible in electroconvection of homeotropically aligned liquid crystals. We present a weakly nonlinear analysis leading to amplitude equations which couple the short-wavelength patterning mode with the Goldstone mode re

L. Gerland, C. Spieles, M. Bleicher, H. Stoecker

The stopping behaviour of baryons in massive heavy ion collisions (at SPS, RHIC and LHC) is investigated within different microscopic models. At SPS-energies the predictions range from full stopping to virtually total transparency. Experimental data are indicating strong stopping. The initial baryo-chemical potentials and temperatures at collider energies an

G. Piller, W. Melnitchouk, A. W. Thomas

A covariant formulation of spin-dependent deep-inelastic scattering from nuclei is presented. In the relativistic impulse approximation the inclusive nuclear cross section is described in terms of the amplitude for forward, virtual-photon scattering from an off-mass-shell nucleon. The general structure of the off-shell nucleon hadronic tensor is derived, and

Doron Zeilberger

Mills, Robbins, and Rumsey conjectured, and Zeilberger proved, that the number of alternating sign matrices of order $n$ equals $A(n):={{1!4!7! ... (3n-2)!} \over {n!(n+1)! ... (2n-1)!}}$. Mills, Robbins, and Rumsey also made the stronger conjecture that the number of such matrices whose (unique) `1&#39; of the first row is at the $r^{th}$ column, equals $A(

E. C. Marino, F. I. Takakura

We introduce and study a pure gauge abelian theory in 2+1D in which massive quantum vortex states do exist in the spectrum of excitations. This theory can be mapped in a three dimensional gas of point particles with a logarithmic interaction, in the grand-canonical ensemble. We claim that this theory is the 2+1D analog of the Sine-Gordon, the massive vortice

Ali H. Chamseddine, Alain Connes

We propose a new action principle to be associated with a noncommutative space $(\Ac ,\Hc ,D)$. The universal formula for the spectral action is $(ψ,Dψ) + \Trace (χ(D /$ $\Lb))$ where $ψ$ is a spinor on the Hilbert space, $\Lb$ is a scale and $χ$ a positive function. When this principle is applied to the noncommutative space defined by the spectrum of the st

John Brodie

We discuss $SU(N_c)$ gauge theory coupled to two adjoint chiral superfields $X$ and $Y$, and a number of fundamental chiral superfields $Q^i$. We add a superpotential that has the form of Arnold&#39;s $D$ series $W = \Tr X^{k+1} + \Tr XY^2$. We present a dual description in terms of an $SU(3kN_f - N_c)$ gauge theory, and we show that the duality passes many

Noboru Kawamoto, Eisaku Ozawa, Kazuhiko Suehiro

We present a quantization of previously proposed generalized Chern-Simons theory with $gl(1,{\bf R})$ algebra in 1+1 dimensions. This simplest model shares the common features of generalized CS theories: on-shell reducibility and violations of regularity. On-shell reducibility of the theory requires us to use the Lagrangian Batalin-Vilkovisky and/or Hamilton

G. D&#39;Ambrosio, J. Portoles

We compute the one-loop unitarity corrections O(p^6) from K^+ -> pi^+ pi^+ pi^- to K^+ -> pi^+ gamma gamma and we find they are relevant, increasing the leading order prediction for the width in a 30-40%. The contributions of local O(p^6) amplitudes, generated by vector meson exchange, are discussed in several models and we conclude that the vector resonance

J. A. Casas, A. Lleyda, C. Muñoz

We examine some physically relevant implications of potentially dangerous charge and color breaking minima for supersymmetric models. First, we analyze the stability of the corresponding constraints with respect to variations of the initial scale for the running of the soft breaking terms, finding that the larger the scale is, the stronger the bounds become.

Bing An Li

The meson fields are simulated by quark operators and an effective chiral theory of mesons is presented. There are spontaneous chiral symmetry breaking and dynamical chiral symmetry breaking. Theoretical results agree with data well.

Walter T. Giele, Stephane Keller, Eric Laenen

We present the next-to-leading order QCD corrections to the production of a $W$-boson in association with a jet containing a heavy quark. The calculation is fully differential in the final state particle momenta and includes the mass of the heavy quark. We study for the case of the Tevatron the sensitivity of the cross section to the strange quark distributi

Amol S. Dighe, Jonathan L. Rosner

Phases of elements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, as obtained using decays of $B$ mesons to $π^+ π^-$, $π^\pm K^\mp$, and $π^+ K^0$ or $π^- \overline{K}^0$, are shown to have a class of discrete ambiguities. In most cases these can be eliminated using other information on CKM phases.

Emanuel Norrbin

We have investigated some observable consequences of colour reconnection in the reaction e+e- -> W+ W- -> q_1 qbar_2 q_3 qbar_4. We use a measure based on the momentum structure of the event, comparing reconnected events with `standard&#39; ones. Some different recoupling models are described and studied as well as simpler toy models to show where the effect

Da-Xin Zhang

Predictions of two channels in the three-bod decays of the charmed mesons are made within the heavy hadron chiral perturbation theory. There still exists the problem that the theoretical expectation is too small compared to the experimental data.

T. Hotta, K. -I. Izawa, T. Yanagida

We investigate low-energy models of supersymmetry (SUSY) breaking by means of vector-like gauge theories for dynamical SUSY breaking. It is not necessary to introduce messenger gauge interactions utilized so far to mediate the SUSY breaking to the standard-model sector, which reduces complication in the model building. We also consider various other ways of

S. V. Chekanov, V. I. Kuvshinov

A new multiplicity distribution with multifractal properties which can be used in high-energy physics and quantum optics is proposed. It may be considered as a generalization of the negative-binomial distribution. We find the structure of the generating function for such distribution and discuss its properties.

Raymond Frey

An overview of top physics and phenomenology at a high-energy linear collider is presented. A comprehensive study of top quark physics is possible at such a facility. The unique threshold production of top pairs would provide measurements of fundamental properties, such as mass and total decay width, to unmatched precision. Above threshold, the full set of S

Hiroyuki Kawamura

We analyze the twist-4 contributions to Bjorken and Ellis-Jaffe sum rules for spin-dependent structure function $g_1(x, Q^2 )$. We investigate the anomalous dimensions of the twist-4 operators which determine the logarithmic correction to the $1/Q^2$ behavior of the twist-4 contribution by evaluating off-shell Green&#39;s functions in both flavor non-singlet

C. Michael, A. M. Green, P. S. Spencer

We use lattice sum rules for the static quark potential to determine the beta-function for symmetric and asymmetric lattices non-perturbatively. We also study the colour field distributions in excited gluonic states.

A. Di Giacomo

A disorder parameter is constructed which signals the condensation of vortices. The construction is tested by numerical simulations. Advances in the understanding of the basic properties of QCD vacuum will be reported. Three main subjects will be touched: 1) Condensation of monopoles and confinement. 2) Topology, or instanton physics. 3) Gauge invariant fiel

Y. Choquet-Bruhat, J. W. York,

We review some well posed formulations of the evolution part of the Cauchy problem of General Relativity that we have recently obtained. We include also a new first order symmetric hyperbolic system based directly on the Riemann tensor and the full Bianchi identities. It has only physical characteristics and matter sources can be included. It is completely e

Tanmoy Bhattacharya, Salman Habib, Emil Mottola

We critically examine the recent claim (gr-qc/9603008) of a ``new effect&#39;&#39; of gravitationally induced quantum mechanical phases in neutrino oscillations. A straightforward exercise in the Schwarzschild coordinates appropriate to a spherically symmetric non-rotating star shows that, although there is a general relativistic effect of the star&#39;s gra

Jacek Brodzki

These lecture notes contain an exposition of basic ideas of K-theory and cyclic cohomology. I begin with a list of examples of various situations in which the K-functor of Grothendieck appears naturally, including the rudiments of the topological and algebraic K-theory, K-theory of C^*-algebras, and K-homology. I then discuss elementary properties of cyclic

K. J. Thomas, J. T. Nicholls, M. Y. Simmons, M. Pepper

In zero magnetic field, conductance measurements of clean one-dimensional (1D) constrictions defined in GaAs/AlGaAs heterostructures show twenty-six quantized ballistic plateaux, as well as a structure close to $0.7(2e^2/h)$. In an in-plane magnetic field all the 1D subbands show Zeeman splitting and in the wide channel limit the $g$-factor is $\mid g \mid =

Giancarlo Franzese

The percolation of Kandel, Ben-Av and Domany clusters for 2d fully frustrated Ising model is extensively studied through numerical simulations. Critical exponents, cluster distribution and fractal dimension of percolative cluster are given.