October 1998 arXiv papers — page 12

W. A. Atkinson

The effects of chain disorder on superconductivity in YBa_2Cu_3O_{7-δ} are discussed within the context of a proximity model. Chain disorder causes both pair-breaking and localization. The hybridization of chain and plane wavefunctions reduces the importance of localization, so that the transport anisotropy remains large in the presence of a finite fraction

R. Kaminski, L. Lesniak, B. Loiseau

Properties of scalar-isoscalar mesons are analysed using separable interactions in three decay channels: pion-pion, kaon-antikaon and an effective 2pion-2pion. We obtain different solutions by fitting various data on the pion-pion and kaon-antikaon phase shifts and inelasticities including the CERN-Cracow-Munich measurements of the pion- p --> pion+ pion- n

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

We find new, local, non-supersymmetric conformal field theories obtained by relevant deformations of the N=4 super Yang Mills theory in the large $N$ limit. We contruct interpolating supergravity solutions that naturally represent the flow from the N=4 super Yang Mills UV theory to these non-supersymmetric IR fixed points. We also study the linearization aro

T. Baumann, H. Geissel, H. Lenske, K. Markenroth

The fragment separator FRS at GSI was used as an energy-loss spectrometer to measure the longitudinal momentum distributions of {16,18}C fragments after one-neutron removal reactions in {17,19}C impinging on a carbon target at about 910 MeV/u. The distributions in the projectile frames are characterized by a FWHM of 141+-6 MeV/c for {16}C and 69+-3 MeV/c for

Anil K. Patnaik, G. S. Agarwal

Spontaneous emission can create coherences in a multilevel atom having close lying levels, subject to the condition that the atomic dipole matrix elements are non-orthogonal. This condition is rarely met in atomic systems. We report the possibility of bypassing this condition and thereby creating coherences by letting the atom with orthogonal dipoles to inte

H. Päs, M. Hirsch, H. V. Klapdor-Kleingrothaus

Neutrinoless double beta decay induced by light Majorana neutrino exchange between two decaying nucleons with squark/slepton exchange inside one and W exchange inside the other nucleon (so-called vector-scalar exchange) gives stringent limits on R-parity violating interactions. We have extended previous work by including the tensor contribution to the transi

Robert Marnelius, Niclas Sandstrom

There is an elaborated abstract form of BRST quantization on inner product spaces within the operator formalism which leads to BRST invariant states of the form |ph>=e^{[Q,ψ]} |ϕ> where ψis a gauge fixing fermion, and where |ϕ> is a BRST invariant state determined by simple hermitian conditions. These state representations are closely related to the path int

Gennady A. El, Alexander L. Krylov

We introduce a new concept, Stochastic Soliton Lattice, as a random process generated by a finite-gap potential of the Shroedinger operator. We study the basic properties of this stochastic process and consider its KdV evolution

J. Jakiel, V. S. Olkhovsky, Erasmo Recami

It is shown that the Hartman-Fletcher effect is valid for all the known expressions of the mean tunnelling time, in various nonrelativistic approaches, for the case of finite width barriers without absorption. Then, we show that the same effect is not valid for the tunnelling time mean-square fluctuations. On the basis of the Hartman-Fletcher effect and the

G. S. Agarwal

I consider the interaction of a superposition of mesoscopic coherent states and its approach to a mixed state as a result of a suitably controlled environment. I show how the presence of a gain medium in a cavity can lead to diagonalization in coherent state basis in contrast to the standard model of decoherence. I further show how the new model of decoheren

David J. Wales

Recent far-infrared vibration-rotation tunneling (FIR-VRT) experiments pose new challenges to theory because the interpretation and prediction of such spectra requires a detailed understanding of the potential energy surface (PES) away from minima. In particular we need a global description of the PES in terms of a complete reaction graph. Hence all the tran

David J. Wales

Rearrangement mechanisms of the water dimer and the cage form of the water hexamer are examined theoretically with particular reference to tunneling splittings and spectroscopy. The three lowest barrier rearrangements of the water dimer are characterized by {\it ab initio} methods and compared with the results of previous constrained calculations. The accept

Horst Mueller

We extend the effective field theory approach which successfully describes ordinary nuclei and nuclear matter to incorporate strangeness in nuclear structure. Central object is a chiral effective Lagrangian involving the baryon octet, the Goldstone boson octet, the vector meson octet and a light scalar singlet. According to the rules of effective field theor

F. M. Lev, E. Pace, G. Salme`

Within front-form dynamics and in the Breit frame where initial and final three-momenta of the system are directed along the $z$ axis, Poincaré covariance constrains the current operator only through kinematical rotations around the $z$ axis. Therefore, in this frame the current can be taken in the one-body form. Applications to deep inelastic structure func

E. Pace, G. Salme`, S. Simula

The helicity amplitudes for the transitions $N-S_{11}$ and $N-S_{31}$ are presented. The amplitudes have been obtained within our front-form CQM model, based on hadron eigenstates of a relativistic mass operator and CQ current with Dirac and Pauli form factors.

HAPPEX Collaboration, K. A. Aniol

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G_E^s. The result, A=-14.5 +- 2.2 ppm, is consiste

R. Wurzinger, O. Bing, M. Boivin, P. Courtat

The polarized d d -> alpha X reaction at beam energies close to the eta threshold shows very strong structure in the missing mass corresponding to the ABC enhancement. The deuteron tensor analysing power A_yy, and the slope of the vector analysing power A_y with respect to angle, have been measured for this reaction around the forward direction. Both signals

Elizabeth Gasparim

Let M(j) denote the moduli space of bundles on the blown-up plane which restrict to the exceptional divisor as O(j)+O(-j). We show that there is a topological embedding of M(j) into M(j+1).

Andrew G. Bakan

Final representation of all those measures $μ$ for which algebraic polynomials are dense in $L_p(R, dμ)$ is found. The weighted analogue of the Weierstrass polynomial approximation theorem and a new version of the M. Krein's theorem about partial fraction decomposition of reciprocal of an entire function are established.

Ph. Ellia, A. Hirschowitz, L. Manivel

A Steiner bundle over the projective 3-space is the kernel in a trivial bundle of a morphism defined by a matrix of linear forms. We produce various Steiner bundles E of rank n such that E(1) has n-1 sections, the dependency locus of which is a smooth curve.

Adam D. Helfer, Andrew S. I. D. Lang

We compute the expectations of the squares of the electric and magnetic fields in the vacuum region outside a half-space filled with a uniform non-dispersive dielectric. This gives predictions for the Casimir-Polder force on an atom in the `retarded' regime near a dielectric. We also find a positive energy density due to the electromagnetic field. This w

J. Alfaro, L. F. Urrutia

An heuristic derivation of the tranformation law for the Berezin integration measure in noncompact supermanifolds, obtained by Roshstein \cite{Ro}, is presented.

Shamit Kachru, Eva Silverstein

It has recently been suggested that in certain special nonsupersymmetric type II string compactifications, at least the first two perturbative contributions to the cosmological constant $Λ$ vanish. Support for perturbative vanishing beyond 1-loop (as well as evidence for the absence of some nonperturbative contributions) has come from duality arguments. Ther

A. Donini, E. Gabrielli, B. Gavela

We study the effects of quenching in Super-Yang-Mills theory. While supersymmetry is broken, the lagrangian acquires a new flavour U(1 | 1) symmetry. The anomaly structure thus differs from the unquenched case. We derive the corresponding low-energy effective lagrangian. As a consequence, we predict the mass splitting expected in numerical simulations for pa

Bogdan Morariu, Bruno Zumino

After a brief review of matrix theory compactification leading to noncommutative supersymmetric Yang-Mills gauge theory, we present solutions for the fundamental and adjoint sections on a two-dimensional twisted quantum torus in two different gauges. We also give explicit transformations connecting different representations which have appeared in the literat

Hael Collins, Howard Georgi

The S_3 symmetry corresponding to permuting the positions of the quarks within a baryon allows us to study the 70-plet of L=1 baryons without an explicit choice for the spatial part of the quark wave functions: given a set of operators with definite transformation properties under the spin-flavor group SU(3) x SU(2) and under this S_3, the masses of the bary

C. D. Froggatt, M. Gibson, H. B. Nielsen, D. J. Smith

We describe the Anti-Grand Unification Model (AGUT) and the Multiple Point Principle (MPP) used to calculate the values of the Standard Model gauge coupling constants in the theory, from the requirement of the existence of degenerate vacua. The application of the MPP to the pure Standard Model predicts the existence of a second minimum of the Higgs potential

Eric Braaten

I describe the NRQCD factorization approach to the inclusive production of heavy quarkonium, contrasting it with the color-singlet and color evaporation models. These approaches differ dramatically in their assumptions about the roles played by color and spin in the production process. They also differ dramatically in their predictions for the production of

C. D. Froggatt, H. B. Nielsen

From considerations of the number of matrix elements of different orders of magnitude in the quark and charged lepton mass matrices, we suggest that the underlying gauge group responsible for the spectrum should have several---actually of the order of 7 to 10---cross product factors. This is taken to support our AGUT gauge group $SMG^3 \times U(1)_f$ which,

D. Bartz, Fl. Stancu

We study the short-range nucleon-nucleon interaction in a nonrelativistic chiral constituent quark model by diagonalizing a Hamiltonian containing a linear confinement and a Goldstone boson exchange interaction between quarks. A finite six-quark basis obtained from single particle cluster model states was previously used. Here we show that the configurations

L. A. Anchordoqui, M. T. Dova, L. N. Epele, S. J. Sciutto

Studies of the influence of different hadronic models on extensive air showers at ultra-high energies are presented. The hadronic models considered are those implemented in the well-known QGSJET and SIBYLL event generators. The different approaches used in both codes to model the underlying physics is analyzed using computer simulations performed with the pr

N. G. Antoniou, Y. F. Contoyiannis, F. K. Diakonos, C. G. Papadopoulos

We investigate the geometry of the critical fluctuations for a general system undergoing a thermal second order phase transition. Adopting a generalized effective action for the local description of the fluctuations of the order parameter at the critical point ($T=T_c$) we show that instanton-like configurations, corresponding to the minima of the effective

Amol Dighe, Saunak Sen

The time-dependent angular distributions of decays of neutral $B$ mesons into two vector mesons contain information about the lifetimes, mass differences, strong and weak phases, form factors, and CP violating quantities. A statistical analysis of the information content is performed by giving the ``information'' a quantitative meaning. It is shown t

Susumu Koretune

We show that the chiral $SU(n)\otimes SU(n)$ flavor symmetry on the null-plane severely restricts the sea quarks in the baryon octet. It predicts large asymmetry for the light sea quarks $(u,d,s)$, and universality and abundance for the heavy sea quarks. Further it is shown that existence of the heavy sea quarks constrained by the same symmetry reduces the t

Y. M. Cho, Y. -Y. Keum

We study the possibility that the dilaton plays the role of the dark matter of the universe. We find that the condition for the dilaton to be the dark matter of the universe strongly restricts its mass to be around 0.5 keV or 270 MeV. For the other mass ranges, the dilaton either undercloses or overcloses the universe. The 0.5 keV dilaton has the free-stream

Ashoke Sen

In this talk I review recent developments in superstring theory. In the first half of the talk I discuss some of the earlier developments in this subject. This includes a review of the status of string theory as a unified theory of gravity and other interactions, the role of duality in string theory, and application of string theory to the problem of informa

MILC Collaboration, C. Bernard, C. DeTar, Steven Gottlieb

We made an extensive study of the light hadron spectrum using the Wilson gauge action and Kogut-Susskind quarks. Using both dynamical quarks and the quenched approximation, we determine hadron masses for five and four gauge couplings respectively, with at least five quark masses at each coupling. In the continuum limit, we find a significant difference betwe

J. J. Godina, Y. Meurice, M. B. Oktay

We calculate the critical exponent gamma of Dyson's hierarchical model by direct fits of the zero momentum two-point function, calculated with an Ising and a Landau-Ginzburg measure, and by linearization about the Koch-Wittwer fixed point. We find gamma= 1.299140730159 plus or minus 10^(-12). We extract three types of subleading corrections (in other wor

Ph. de Forcrand, M. Garcia Perez, J. E. Hetrick, E. Laermann

To elucidate the role played by instantons in chiral symmetry breaking, we explore their properties in full QCD, around the critical temperature. We study in particular spatial correlations between low-lying Dirac eigenmodes and instantons. Our measurements are compared with the predictions of instanton-based models.

Arie Bodek

We report on the performance of a prototype CMS Hadron Barrel Calorimeter (HCAL) module in a test beam. The prototype sampling calorimeter used copper absorber plates and scintillator tiles with wavelength shifting fibers for readout. Placing a lead tungstate crystal electromagnetic calorimeter in front of HCAL affects the linearity and energy resolution of

Dmitriy Yu. Shabalkin

In present article effective nonlinear sigma model (NSM) is considered. Einstein equation solution, corresponded to the chiral fields determined by functional parameter method, are presented. Effective NSM of stationary axially-symmetric gravitational field is constructed. Motion equations are solved exactly by functional parameter method. Einstein equations

Ion Muslea

In this paper we describe SYNERGY, which is a highly parallelizable, linear planning system that is based on the genetic programming paradigm. Rather than reasoning about the world it is planning for, SYNERGY uses artificial selection, recombination and fitness measure to generate linear plans that solve conjunctive goals. We ran SYNERGY on several domains (

Jian-Xin Zhu, W. Kim, C. S. Ting, Chia-Ren Hu

A set of coupled time-dependent Ginzburg-Landau equations (TDGL) for superconductors of mixed d- and s-wave symmetry are derived microscopically from the Gor'kov equations by using the analytical continuation technique. The scattering effects due to impurities with both nonmagnetic and magnetic interactions are considered. We find that the d- and s-wave

G. Ravikumar et al

We report magnetization hysteresis measurements in the peak effect region of a very clean single crystal of superconducting 2H-NbSe$_2$ at temperatures very close to T$_c$(0). Through measurement of minor magnetization curves, we infer the equilibrium magnetization curve across the PE region. We observe a small first order like change in equilibrium magnetiz

S. S. Banerjee et al

We report on the discovery of the simultaneous observation of Fishtail Effect (FE) and Peak Effect (PE) via the study of angular dependence of dc magnetization hysteresis loops in a clean crystal of 2H-NbSe$_2$. These result clarify and establish the occurrence of the reentrant characteristics in order to disorder transformation in an isothermal scan close t

Haye Hinrichsen, Geza Odor

A solid-on-solid growth model for dimer adsorption and desorption is introduced and studied numerically. The special property of the model is that dimers can only desorb at the edges of terraces. It is shown that the model exhibits a roughening transition from a smooth to a rough phase. In both phases the interface remains pinned to the bottom layer and does

Pep Español, Mar Serrano

We discuss theoretically the behavior of the velocity autocorrelation function in the Dissipative Particle Dynamics model. Two dynamical regimes are identified depending on the dimensionless model parameters. For low frictions a mean field behavior is observed in which the kinetic theory for DPD provides good predictions. For high frictions, collective hydro

M. Bayindir, B. Tanatar, Z. Gedik

We examine the possibility of Bose-Einstein condensation in one-dimensional interacting Bose gas subjected to confining potentials of the form $V_{\rm ext}(x)=V_0(|x|/a)^γ$, in which $γ< 2$, by solving the Gross-Pitaevskii equation within the semi-classical two-fluid model. The condensate fraction, chemical potential, ground state energy, and specific heat o

J. Piasecki, Ch. Gruber

The controversial problem of an isolated system with an internal adiabatic wall is investigated with the use of a simple microscopic model and the Boltzmann equation. In the case of two infinite volume one-dimensional ideal fluids separated by a piston whose mass is equal to the mass of the fluid particles we obtain a rigorous explicit stationary non-equilib

J. Martinek, J. Barnas, G. Michalek, B. R. Bulka

Spin dependent single electron tunneling in ferromagnetic double junctions is analysed theoretically in the limit of sequential tunneling. The influence of discrete energy spectrum of the central electrode (island)on the spin accumulation, spin fluctuations and tunnel magnetoresistance is analysed numerically in the case of a nonmagnetic island. It is shown

D. A. Gorokhov, R. A. Suris, V. V. Cheianov

In this work we present a theoretical study of EELS (electron-energy-loss spectroscopy) experiments on the ${\rm C}_{60}$ molecule. Our treatment of the problem is based on the simple two-fluid model originally proposed for the description of plasma oscillations in graphite and fullerenes (see Refs.\cite{14,15,16}). It is shown that in spite of the simplicit

M. -Carmen Miguel, R. Pastor-Satorras

Experimental studies on the irreversible growth of field-induced chains of dipolar particles suggest an asymptotic power-law behavior of several relevant quantities. We introduce a Monte Carlo model of chain growth that explicitly incorporates the anisotropic diffusion characteristic of a rod-like object. Assuming a simple power-law form for the mean cluster

Ch. Preis, Ch. Helm, J. Keller, A. Sergeev

The coupling of Josephson oscillations in layered superconductors is studied with help of a tunneling Hamiltonian formalism. The general form of the current density across the barriers between the superconducting layers is derived. The induced charge fluctuations on the superconducting layers lead to a coupling of the Josephson oscillations in different junc

Alex Kamenev, Anton Andreev

We develop a field theory formalism for the disordered interacting electron liquid in the dynamical Keldysh formulation. This formalism is an alternative to the previously used replica technique. In addition it naturally allows for the treatment of non-equilibrium effects. Employing the gauge invariance of the theory and carefully choosing the saddle point i

J. -R. Grasso, D. Sornette

We examine the hypothesis proposed in recent years by several authors that the crust is in a self-organized critical (SOC) state by exploring how the SOC concept can help in understanding the observed earthquake clustering on relatively narrow fault domains and the phenomenon of induced seismicity. We review the major reported cases of induced seismicity in

Yung-Tae Kim, Nikolas Provatas, Nigel Goldenfeld, Jonathan Dantzig

We compare time-dependent solutions of different phase-field models for dendritic solidification in two dimensions, including a thermodynamically consistent model and several ad hoc models. The results are identical when the phase-field equations are operating in their appropriate sharp interface limit. The long time steady state results are all in agreement

A. Panaitescu, P. Meszaros

We simulate the dynamics of the interaction between relativistically expanding spherically symmetric shells using a 1-dimensional hydrodynamic code and calculate spectra and light-curves arising from such collisions by integrating the synchrotron and inverse Compton emission of the shocked gas. The numerical results reflect the most important features observ

Matias Zaldarriaga, Uros Seljak

Gravitational lensing distorts the cosmic microwave background (CMB) anisotropies and imprints a characteristic pattern onto it. The distortions depend on the projected matter density between today and redshift $z \sim 1100$. In this paper we develop a method for a direct reconstruction of the projected matter density from the CMB anisotropies. This reconstr

Tsvi Piran

Gamma-ray bursts (GRBs) have puzzled astronomers since their accidental discovery in the late sixties. The BATSE detector on the COMPTON-GRO satellite has been detecting one burst per day for the last six years. Its findings have revolutionized our ideas about the nature of these objects. They have shown that GRBs are at cosmological distances. This idea was

R. C. Kraan-Korteweg

The systematic mapping of obscured and optically invisible galaxies behind the Milky Way through complementary surveys are important in arriving at the whole-sky distribution of complete galaxy samples and therewith for our understanding of the dynamics in the local Universe. In this paper, a status report is given of the various deep optical, near infrared

A. Caccianiga, T. Maccacaro, A. Wolter, R. Della Ceca

We present the scientific goals, the strategy and the first results of the REX project, an effort aimed at creating a sizable and statistically complete sample of Radio Emitting X-ray sources (REX) using the available data from a VLA survey and the ROSAT PSPC archive. Through a positional cross-correlation of the two data sets we have derived a sample of abo

D. H. Hughes, J. S. Dunlop, E. N. Archibald, S. Rawlings

A systematic survey measuring the submillimetre continuum luminosity in radio galaxies between redshifts z ~ 0.1 - 5 is currently in progress. The first results from observations with the bolometer array SCUBA on the JCMT suggest a trend of increasing submillimetre luminosity with redshift out to z ~ 4. Assuming the continuum emission at 850um is dominated b

C. Marinoni, G. Giuricin, B. Costantini, P. Monaco

We use an all--sky, complete sample of nearby galaxies, extracted from the LEDA data base, to map the optical galaxy density field in the nearby universe. In order to determine this field, we correct the redshift--dependent distances by testing some peculiar velocity field models and we correct the galaxy number density for the incompletion of the galaxy sam

M. Cocchi, A. Bazzano, L. Natalucci, P. Ubertini

We report evidence of type-I X-ray bursting activity from the transient 1RXS J170930.2-263927 when it was in outburst early 1997. This identifies the source as a probable low-mass X-ray binary containing a neutron star. The error boxes of the detected bursts and of the persistent emission, as obtained with the Wide Field Cameras on board the BeppoSAX satelli

Yoshiaki Taniguchi, Akira Yoshino, Youichi Ohyama, Shingo Nishiura

The origin of huge infrared luminosities of ultraluminous infrared galaxies (ULIGs) is still in question. Recently, Genzel et al. made mid-infrared (MIR) spectroscopy of a large number of ULIGs and found that the major energy source in them is massive stars formed in the recent starburst activity; i.e., $\sim$ 70% -- 80% of the sample are predominantly power

Marc Postman

By virtue of their high galaxy space densities and their large spatial separations, clusters are efficient and accurate tracers of the large-scale density and velocity fields. Substantial progress has been made over the past decade in the construction of homogeneous, objectively derived cluster catalogs and in characterizing the spatial distribution of clust

M. Cvetic, H. Lu, C. N. Pope

We study the spacetimes of the near-horizon regions in D3-brane, M2-brane and M5-brane configurations, in cases where there is a pp-wave propagating along a direction in the world-volume. While non-extremal configurations of this kind locally have the same Carter-Novotny-Horsky-type metrics as those without the wave, taking the BPS limit results instead in K

Kohji Yoshikawa, Yasushi Suto

We describe a non-parametric method to reconstruct gas density and temperature profiles of galaxy clusters from observations of X-ray surface brightness, emission-weighted temperature and the y-parameter through the Sunyaev-Zel&#39;dovich effect. This method is based on the inversion of the projected profiles under the spherically symmetric approximation, wh

R. Schack, C. M. Caves

We present two complementary ways in which Saraceno&#39;s symmetric version of the quantum baker&#39;s map can be written as a shift map on a string of quantum bits. One of these representations leads naturally to a family of quantizations of the baker&#39;s map.

Minghong G. Wu, Michael W. Deem

We present a new, biased Monte Carlo scheme for simulating complex, cyclic peptides. Backbone atoms are equilibrated with a biased rebridging scheme, and side-chain atoms are equilibrated with a look-ahead configurational bias Monte Carlo. Parallel tempering is shown to be an important ingredient in the construction of an efficient approach.

H. -J. He, C. -P. Yuan

We propose a new method for detecting a charged (pseudo-)scalar at colliders, based upon the observation that its Yukawa coupling to charm and bottom quarks can be large due to a significant mixing of the top and charm quarks. After analyzing the typical flavor mixing allowed by low energy data in the topcolor and the generic two-Higgs doublet models, we stu

R. J. Rand, S. D. Lord, J. L. Higdon

We have used the Owens Valley Millimeter Array to map 12CO (J=1-0) along a 3.5 kpc segment of M83&#39;s eastern spiral arm at resolutions of 6.5&#34;x3.5&#34;, 10&#34;, and 16&#34;. The CO emission in most of this segment lies along the sharp dust lane demarking the inner edge of the spiral arm, but beyond a certain point along the arm the emission shifts do

James W. York,

The initial-value problem is posed by giving a conformal three-metric on each of two nearby spacelike hypersurfaces, their proper-time separation up to a multiplier to be determined, and the mean (extrinsic) curvature of one slice. The resulting equations have the {\it same} elliptic form as does the one-hypersurface formulation. The metrical roots of this f

A. Dumitru, C. Spieles

We employ the Monte-Carlo PYTHIA to calculate the transverse mass spectra of various hadrons and their inverse slopes T* at m_T-m=1.5-2 GeV in p+p reactions at sqrt(s)=200 GeV. Due to (multiple) minijet production T* increases as a function of the hadron mass. Moreover, the T*(m) systematics has a ``discontinuity&#39;&#39; at the charm threshold, i.e. the in

G. L. Kane, S. F. King

We analyse the fine-tuning constraints arising from absence of superpartners at LEP, without strong universality assumptions. We show that such constraints do not imply that charginos or neutralinos should have been seen at LEP, contrary to the usual arguments. They do however imply relatively light gluinos $(m_{\tilde g} \lsim 350 GeV)$ and/or a relation be

Michele Simionato

We give a wilsonian formulation of non-abelian gauge theories explicitly consistent with axial gauge Ward identitities. The issues of unitarity and dependence on the quantization direction are carefully investigated. A wilsonian computation of the one-loop QCD beta function is performed.

C. Hofman, E. Verlinde

We discuss Born-Infeld on the noncommutative two-torus as a description of compactified string theory. We show that the resulting theory, including the fluctuations, is manifestly invariant under the T-duality group SO(2,2;Z). The BPS mass even has a full SL(3,Z)xSL(2,Z) U-duality symmetry. The direct identification of the noncommutative parameter \theta wit

E. N. Bukina, V. M. Dubovik, V. S. Zamiralov

It is shown that an alternative form of the parity-nonconserving (PNC) transition electromagnetic current resolves partly a puzzle with the Hara theorem. New formulation of it has allowed PNC weak radiative hyperon transitions of the charged hyperons $Σ^{+} \Rightarrow p + γ$ and $Ξ^{-} \Rightarrow Σ^{-} + γ$ revealing hitherto unseen transition toroid dipol

Javier Ferrandis

In the most general R-parity violating model, including both bilinear and trilinear terms, the sneutrino receives a vacuum expectation value. We investigate the constraints on this vev following a basis independent approach, highlighting the relations between the three most popular basis. We study the prediction for the tau neutrino mass which follows from t

Yuri G. Prokhorov

In this paper we apply Shokurov&#39;s inductive method to study terminal and canonical singularities. As an easy consequence of the Minimal Model Program we show that for any three-dimensional log terminal singularity there exists some special, so called, plt blow-up. We discuss properties of them and construct some examples.

P. Bouwknegt, K. Schoutens

We systematically study the exclusion statistics for quasi-particles for Conformal Field Theory spectra by employing a method based on recursion relations for truncated spectra. Our examples include generalized fermions in c<1 unitary minimal models, Z_k parafermions, and spinons for the su(n)_1, so(n)_1 and sp(2n)_1 Wess-Zumino-Witten models. For some of th

Martin Goliath, Max Karlovini, Kjell Rosquist

A recipe is presented for obtaining Lax tensors for any n-dimensional Hamiltonian system admitting a Lax representation of dimension n. Our approach is to use the Jacobi geometry and coupling-constant metamorphosis to obtain a geometric Lax formulation. We also exploit the results to construct integrable spacetimes, satisfying the weak energy condition.

V. Dzhunushaliev, D. Singleton

On the basis of an algebraic relation between torsion and a classical spinor field a new interpretation of Einstein-Cartan gravity interacting with classical spinor field is proposed. In this approach the spinor field becomes an auxiliary field and the dynamical equation for this field (the Heisenberg equation) is a dynamical, gravitational equation for tors

I. Peschel, M. Kaulke, Ö. Legeza

The spectra which occur in numerical density-matrix renormalization group (DMRG) calculations for quantum chains can be obtained analytically for integrable models via corner transfer matrices. This is shown in detail for the transverse Ising chain and the uniaxial XXZ Heisenberg model and explains in particular their exponential character in these cases.

Adam Doliwa, Manuel Manas, Luis Martinez Alonso

The bilinear equations of the $N$-component KP and BKP hierarchies and a corresponding extended Miwa transformation allow us to generate quadrilateral and circular lattices from conjugate and orthogonal nets, respectively. The main geometrical objects are expressed in terms of Baker functions.

Z. Maassarani

Models generalizing the su(2) XX spin-chain were recently introduced. These XXC models also have an underlying su(2) structure. Their construction method is shown to generalize to the chains based on the fundamental representations of the A_m Lie algebras. Integrability of the new models is shown in the context of the quantum inverse scattering method. Their

S. B. Leble, N. V. Ustinov

Maxwell-Bloch system describing the resonant propagation of electromagnetic pulses in both two-level media with degeneracy in angle moment projection and three-level media with equal oscillator forces is considered. The inhomogeneous broadening of energy levels is accounted. Binary Darboux Transformation generating the solutions of the system is constructed.

D. S. Freitas, A. Vidiella-Barranco, J. A. Roversi

We have found that, in the intensity-dependent Jaynes-Cummings model, a field initially prepared in a statistical mixture of two coherent states, $|α>$ and $|-α>$, evolves toward a pure state. We have also shown that an even-coherent state turns periodically a into rotated odd-coherent state during the evolution.

K. Riedel, P. Torma, V. Savichev, W. P. Schleich

We identify a new parameter that controls the localization length in a driven quantum system. This parameter results from an additional quantum degree of freedom. The center-of-mass motion of a two-level ion stored in a Paul trap and interacting with a standing wave laser field exhibits this phenomenon. We also discuss the influence of spontaneous emission.

Mario Encinosa

Energies and spatial observables for the $^1Σ_g$ state of the hydrogen molecule in magnetic fields parallel to the proton-proton axis are calculated with a guided random walk Feynman-Kac algorithm. We demonstrate that the accuracy of the results and the simplicity of the method may prove it a viable alternative to large basis set expansions for small molecul

B. Dubetsky, P. R. Berman

A theory of matter wave interference is developed in which resonant optical fields interact with two-level atoms. When recoil effects are included, spatial modulation of the atomic density can occur for times that are greater than or comparable with the inverse recoil frequency. In this regime, the atoms exhibit matter-wave interference. Two specific atom fi

V. L. Eletsky, J. I. Kapusta

The rho-meson mass shift, width broadening, and spectral density at finite temperature and nucleon density are estimated using a general formula which relates the self-energy to the real and imaginary parts of the forward scattering amplitude on the constituents of the medium. We saturate the scattering amplitude at low energies with resonances, while at hig

Scott Pratt, Kevin Haglin

The effect of altered hadron masses is studied for its effect with regard to final-state hadronic observables. It is shown that the final phase space densities of pions and kaons, which can be inferred experimentally, are sensitive to in-medium properties of the excited matter at earlier stages of the collision, but that the sensitivity is significantly mode

T. Rauscher

Recent improvements and remaining problems in the prediction of thermonuclear rates are reviewed. The main emphasis is on statistical model calculations, but the challenge to include direct reactions close to the driplines is also briefly addressed. Further theoretical as well as experimental investigations are motivated.

H. Masui, T. Sato

We propose a new type of Monte-Carlo method which enables us to study the excited state of many-body systems.

Nimai C. Mukhopadhyay, R. M. Davidson

We discuss the effect of model space truncation on current conservation in quark model calculations.

Colin Wilkin

Near-threshold data on meson production in nucleon-nucleon scattering are analysed in the short-range limit which permits a quantitative comparison of the production in two and three-body final states. The relative strengths of different meson productions are broadly in line with the predictions of one-meson-exchange models and it is deviations from these wh

S. Chatyrvedi, V. Gupta

A systematic procedure for generating certain identities involving elementary symmetric functions is proposed. These identities, as particular cases, lead to new identities for binomial and q-binomial coefficients.

Saharon Shelah

We prove that it is consistent that the covering of the ideal of measure zero sets has countable cofinality.

Rich Stankewitz

Let G be a semigroup of rational functions of degree at least two where the semigroup operation is composition of functions. We prove that the largest open subset of the Riemann sphere on which the semigroup G is normal and is completely invariant under each element of G, can have only 0, 1, 2, or infinitely many components.