October 1997 arXiv papers — page 2

A. Gorsky, S. Gukov, A. Mironov

Five and six dimensional SUSY gauge theories, with one or two compactified directions, are discussed. The 5d theories with the matter hypermultiplets in the fundamental representation are associated with the twisted $XXZ$ spin chain, while the group product case with the bi-fundamental matter corresponds to the higher rank spin chains. The Riemann surfaces f

A. Pasquinucci, M. Petrini

We consider the Compton amplitude for the scattering of a photon and a (massless) ``electron/positron'' at one loop (i.e. genus one) in a four-dimensional fermionic heterotic string model. Starting from the bosonization of the world-sheet fermions needed to explicitly construct the spin-fields representing the space-time fermions, we present all the

S. Alam

Keeping in mind the several models of M(atrix) theory we attempt to understand the possible structure of the topological M(atrix) theory ``underlying'' these approaches. In particular we raise the issue about the nature of the structure of the vacuum of the topological M(atrix) theory and how this could be related to the vacuum of the electroweak the

Gustavo Burdman

We derive a condition the short distance coefficients governing $b\to (s,d)\ell^+\ell^-$ transitions must satisfy in order for the forward-backward asymmetry to vanish in the exclusive modes $B\to (K^*,ρ)\ell^+\ell^-$. This relation, which is satisfied in the standard model, involves the coefficient entering in $b\to sγ$ transitions as well as one of the add

M. Bertini, M. Genovese, N. N. Nikolaev, A. V. Pronyaev

In this letter we report the direct perturbative QCD evaluation of twist-4 effects in diffractive DIS. They are large and have a strong impact on the $Q^2$ dependence of diffractive structure functions at large $β$. Based on the AGK rules, we comment on the possible contribution from diffractive higher twists to $\propto {1 \over Q^{2}}$ corrections to proto

R. S. Thorne

We present consistently ordered calculations of the structure functions F_2(x,Q^2) and F_L(x,Q^2), in different expansion schemes. After discussing the standard expansion in powers of alpha_s(Q^2) we consider a leading-order expansion in ln(1/x) and finally an expansion which is leading order in both ln(1/x) and alpha_s(Q^2), and which is the only really cor

A. L. Ayala Filho, M. B. Gay Ducati, E. M. Levin

We study the value of shadowing corrections (SC) in HERA kinematic region in Glauber - Mueller approach. Since the Glauber - Mueller approach was proven in perturbative QCD in the double logarithmic approximation (DLA), we develop the DLA approach for deep inelastic structure function which takes into account the SC. Our estimates show small SC for $F_2$ in

N. N. Achasov, G. N. Shestakov

Over the last twenty years, it was assumed that the reaction $π^-p\to a^0_0(980)n\toπ^0ηn$ at high energies is dominated by $b_1$ Regge pole exchange. We show that the new Brookhaven and Serpukhov data on the $t$ distributions for this reaction can be explained within the framework of the Regge pole model only if the $ρ_2$ Regge pole exchange conspiring with

N. N. Achasov, V. V. Gubin

The potentialities of the production of the $a_0$ and $f_0$ mesons in the $ϕ$ radiative decays are considered based on a new two-channel analysis of the $ππ$ scattering in a energy region near 1 GeV. We predict $BR(ϕ\toγf_0(980))\sim10^{-5}-10^{-4}$ that is a great value for the decay forbidden by the Okubo-Zweig-Iizuka rule. We discuss the four-quark, $K\ba

I. V. Akushevich, A. N. Ilyichev, N. M. Shumeiko

The results for one-loop correction to deep inelastic scattering of longitudinal polarized leptons on longitudinal polarized hadrons are obtained withing the framework of the standard theory of electroweak interactions and ordinary quark-parton model. The on-shell renormalization scheme in t'Hooft-Feynman gauge is applied. The numerical analysis is carri

P. S. Cherzor, N. A. Sveshnikov

We clarify and extend the theorem of Sveshnikov and Tkachov [hep-ph/9512370], which gives an explicit connection between jet observables and energy-momentum tensor. We check the relation between jet observables and energy-momentum tensor for non-scalar (spinor and vector) field, give a correct treatment of the light-cone singularity for massless particles, a

Sergio Caracciolo, Andrea Montanari, Andrea Pelissetto

For the O(N) sigma-model we studied the improvement program for actions with two- and four-spin interactions. An interesting example is an action which is reflection-positive, on-shell improved, and has all the coupling defined on an elementary plaquette. We show the large N solution and preliminary Monte Carlo results for N=3.

Marco Zagermann

The relation between the SL(2,R)/SO(2)- and the SL(2,C)-chiral model that naturally arise within the metric respectively the Ashtekar formulation of two Killing field reduced Einstein gravity is revealed. Both chiral models turn out to be completely equivalent even though the transition from the coset- to the SL(2,C)-model is accompanied by a disappearance o

V. Moncrief, J. E. Nelson

Constants of motion are calculated for 2+1 dimensional gravity with topology R \times T^2 and negative cosmological constant. Certain linear combinations of them satisfy the anti - de Sitter algebra so(2,2) in either ADM or holonomy variables. Quantisation is straightforward in terms of the holonomy parameters, and the modular group is generated by these con

R. Parentani

We re-examine the notions of time and evolution in the light of the mathematical properties of the solutions of the Wheeler-DeWitt equation which are revealed by an extended adiabatic treatment. The main advantage of this treatment is to organize the solutions in series that make explicit both the connections with the corresponding Schrödinger equation as we

Eanna E. Flanagan, Scott A. Hughes

We discuss the extraction of information from detected binary black hole (BBH) coalescence gravitational waves, focusing on the merger phase that occurs after the gradual inspiral and before the ringdown. Our results are: (1) If numerical relativity simulations have not produced template merger waveforms before BBH detections by LIGO/VIRGO, one can band-pass

Igor Podlubny

The Laplace transform method for solving of a wide class of initial value problems for fractional differential equations is introduced. The method is based on the Laplace transform of the Mittag-Leffler function in two parameters. To extend the proposed method for the case of so-called "sequential" fractional differential equations, the Laplace trans

B. Groh, R. Evans, S. Dietrich

We investigate the liquid-vapor interface of the restricted primitive model (RPM) for an ionic fluid using a density-functional approximation based on correlation functions of the homogeneous fluid as obtained from the mean-spherical approximation (MSA). In the limit of a homogeneous fluid our approach yields the well-known MSA (energy) equation of state. Th

Francesco M. Russo

We consider a Lattice Gas model in which the sites interact via infinite-ranged random couplings independently distributed with a Gaussian probability density. This is the Lattice Gas analogue of the well known Sherrington-Kirkpatrick Ising Spin Glass. We present results of replica approach in the Replica Symmetric approximation. Even with zero-mean of the c

M. Houbiers, H. T. C. Stoof, W. I. McAlexander, R. G. Hulet

We use a full coupled channels method to calculate collisional properties of magnetically or optically trapped ultracold 6Li. The magnetic field dependence of the s-wave scattering lengths of several mixtures of hyperfine states are determined, as are the decay rates due to exchange collisions. In one case, we find Feshbach resonances at B=0.08 T and B=1.98

Shoji Yamamoto, S. Brehmer, H. -J. Mikeska

We numerically investigate elementary excitations of the Heisenberg alternating-spin chains with two kinds of spins 1 and 1/2 antiferromagnetically coupled to each other. Employing a recently developed efficient Monte Carlo technique as well as an exact diagonalization method, we verify the spin-wave argument that the model exhibits two distinct excitations

A. Yu. Kasumov, H. Bouchiat, B. Reulet, O. Stephan

We report associated high resolution transmission electron microscopy (HRTEM) and transport measurements on a series of isolated multiwalled carbon nanotubes. HRTEM observations, by revealing relevant structural features of the tubes, shed some light on the variety of observed transport behaviors, from semiconducting to quasi-metallic type. Non Ohmic behavio

Shin-ichi Sasa, Tatsuo Shibata

We extend the Langevin dynamics so that particles can be exchanged with a particle reservoir. We show that grand canonical ensembles are realized at equilibrium and derive the relations of thermodynamics for processes between equilibrium states. As an application of the proposed evolution rule, we devise a simple model of Brownian motors driven by particle e

Tatsuo Shibata, Shin-ichi Sasa

An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Mo

Toru Sakai, Minoru Takahashi

The magnetization process of the S=3/2 antiferromagnetic Heisenberg chain with the single-ion anisotropy D at T=0 is investigated by the exact diagonalization of finite clusters and finite-size scaling analyses. It is found that a magnetization plateau appears at m=1/2 for $D>D_c=0.93 \pm 0.01$. The phase transition with respect to D at D_c is revealed to be

David L. Klein, Richard Roth, Andrew K. L. Lim, A. Paul Alivisatos

The techniques of colloidal chemistry permit the routine creation of semiconductor nanocrystals, whose dimensions are much smaller than those that can be realized using lithographic techniques. The sizes of such nanocrystals can be varied systematically to study quantum size effects or to make novel electronic or optical materials with tailored properties. P

Sanjay Hortikar, Mark Srednicki

An energy eigenfunction in a classically chaotic system is known to have spatial correlations which (in the limit of small $\hbar$) are governed by a microcanonical distribution in the classical phase space. This result is valid, however, only over coordinate distances which are small compared to any relevant classical distance scales (such as the cyclotron

J. P. Gardner, R. S. Hill, S. A. Baum, N. R. Collins

The installation of the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) allows for the first time two-dimensional optical and ultraviolet slitless spectroscopy of faint objects from space. The STIS Parallel Survey (SPS) routinely obtains broad band images and slitless spectra of random fields in parallel with HST observations

H. K. C. Yee, M. J. Sawicki, R. G. Carlberg, H. Lin

This paper provides a brief description of the CNOC2 Redshift Survey being carried out at CFHT, giving the scope, technique, and current status of the survey, and some preliminary results.

Donald M. Terndrup, Piotr Popowski, Andrew Gould, R. Michael Rich

We have detected seven stars with a common proper motion which are located within 2.5 arcminutes of the globular cluster NGC 6522 in the Baade's Window field of the Galactic bulge. We argue that these stars are members of the cluster, and derive a weighted mean proper motion and heliocentric radial velocity of mu_l = 1.4 +/- 0.2 mas/yr, mu_b = -6.2 +/- 0

F. W. Stecker

We present the results of a new estimation of the photodisintegration and propagation of ultrahigh energy cosmic ray (UHCR) nuclei in intergalactic space. The critical interactions for photodisintegration and energy loss of UHCR nuclei occur with photons of the infrared background radiation (IBR). We have reexamined this problem making use of a new determina

T. Lejeune, F. Cuisinier, R. Buser

A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune, Cuisinier & Buser 1997). It covers wide ranges of fundamental parameters: Teff

J. Delabrouille, K. M. Górski, E. Hivon

A number of experiments for measuring anisotropies of the Cosmic Microwave Background use scanning strategies in which temperature fluctuations are measured along circular scans on the sky. It is possible, from a large number of such intersecting circular scans, to build two-dimensional sky maps for subsequent analysis. However, since instrumental effects --

T. P. Downes, T. P. Ray

We present the results of simulations of the development of the Kelvin-Helmholtz (KH) instability in a cooled, slab symmetric system. The parameters were chosen to approximate the physical conditions typically found in jets from young stellar objects (YSOs). The effect of different methods of maintaining the initial equilibrium were examined for varying dens

Simon F. Portegies Zwart, Lev R. Yungelson

The formation and evolution of binaries which contain two neutron stars or a neutron star with a black hole are discussed in detail. The evolution of the distributions in orbital period and eccentricity for neutron star binaries are studied as a function of time. In the model which fits the observations of high mass binary pulsars best the deposition of orbi

Nobuyoshi Makino, Shin Sasaki, Yasushi Suto

The X-ray cluster gas density distribution in hydrostatic equilibrium is computed from the universal density profile of the dark matter halo recently proposed by Navarro, Frenk and White (1996, 1997). If one assumes the isothermality, the resulting distribution is well approximated by the conventional $β$-model. We predict the core radius $r_{c}$, the $β$-pa

T. Dimeo, D. Valls-Gabaud, E. J. Kerins

The amount of dark matter in the solar neighbourhood is a poorly constrained quantity which is nevertheless used to normalise the properties of the dark halo. While the current surveys towards the LMC, SMC and the Galactic bulge probe the dark matter content at large distances from the Sun, the HIPPARCOS satellite provides a unique way to constrain the dark

T. Corbard, G. Berthomieu, J. Provost, P. Morel

Helioseismic inversions, carried out for several years on various ground-based and spatial observations, have shown that the solar rotation rate presents two principal regimes: a quasi-rigid rotation in the radiative interior and a latitude-dependent rotation in the whole convection zone. The thin layer, named solar tachocline, between these two regimes is d

Z. Ran

We consider the locus of irreducible nonsingular rational curves of degree d Pn, n>2, meeting a generic collection of linear subspaces. When this locus is 0 (resp 1)- dimensional, we compute (recursively) its degree (resp. geometric genus). The method is completely elementary and similar to that of (alg-geom/9704004, alg-geom/9708013), where the case n=2 was

Kim Griest, Neda Safizadeh

Hundreds of gravitational microlensing events have now been detected towards the Galactic bulge, with many more to come. The detection of fine structure in these events has been theorized to be an excellent way to discover extra-solar planetary systems along the line-of-sight to the Galactic center. We show that by focusing on high magnification events the p

Tanmoy Bhattacharya, Rajan Gupta

Significant progress has been made in the determination of the light quark masses, using both lattice QCD and sum rule methods, in the last year. We discuss the different methods and review the status of current results. Finally, we review the calculations of bottom and charm quark masses.

C. Ford, I. Sachs

We obtain the parity invariant generating functional for the canonical transformation mapping the Liouville theory into a free scalar field and explain how it is related to the pseudoscalar transformation

P. Bhattacharjee, Qaisar Shafi, F. W. Stecker

Cosmic topological defects in a wide class of supersymmetric theories can simultaneously be sources of higgs particles of mass comparable to the supersymmetry breaking scale $\sim$ TeV, as well as superheavy gauge bosons of mass $\simη$, where $η$ (>> 1 TeV) denotes the associated gauge symmetry breaking scale. For cosmic strings with $η\sim 10^{14}$ GeV, th

E. V. Goldstein, E. M. Wright, P. Meystre

We propose and analyze a way in which effective multicomponent condensates can be created inside high-Q multimode cavities. In contrast to the situation involving several atomic species or levels, the coupling between the various components of the dressed condensates is linear. We predict analytically and numerically confirm the onset of instabilities in the

B. Guiderdoni, E. Hivon, F. R. Bouchet, B. Maffei

This paper proposes a new semi-analytic modelling of galaxy properties in the IR/submm wavelength range, which is explicitly set in a cosmological framework. This type of approach has had some success in reproducing the optical properties of galaxies. We hereafter propose a simple extension to the IR/submm range. We estimate the IR/submm luminosities of ``lu

Aldo H. Romero, David W. Brown, Katja Lindenberg

We present selected results for the Holstein molecular crystal model in one space dimension as determined by the Global-Local variational method, including complete polaron energy bands, ground state energies, and effective masses. We juxtapose our results with specific comparable results of numerous other methodologies of current interest, including quantum

Miao Li

Based on a gas picture of D0-brane partons, it is shown that the entropy, as well as the geometric size of an infinitely boosted Schwarzschild black hole, can be accounted for in matrix theory by interactions involving spins, or interactions involving more than two bodies simultaneously.

C. Panagiotakopoulos, N. Tetradis

We address the issue of fine-tuning of the initial field configuration that can lead to hybrid inflation in the context of global supersymmetry. This problem is generated by the difference between the energy scale at which the Universe emerges from the Planck era and the inflationary scale implied by the COBE observations: V^{1/4} \sim 10^{-3} m_{Pl}. We pro

Marc-Andre Lewis

Using CFT techniques, we compute the disorder-averaged p-th power of the spin-spin correlation function for the ferromagnetic random bonds Potts model. We thus generalize the calculation of Dotsenko, Dotsenko and Picco, where the case p=2 was considered. Perturbative calculations are made up to the second order in epsilon (epsilon being proportional to the c

S Washburn, D Popovic, KP Li, AB Fowler

We review some experimental and theoretical results on the metal-to-insulator transition (MIT) observed at zero magnetic field (B=0) in several two-dimensional electron systems (2DES). Scaling of the conductance and magnetic field dependence of the conductance provide convincing evidence that the MIT is driven by Coulomb interactions among the carriers and i

C. S. Chu, E. Sezgin

Covariant field equations of M-fivebrane in eleven dimensional curved superspace are obtained from the requirement of kappa-symmetry of an open supermembrane ending on a fivebrane. The worldvolume of the latter is a (6|16) dimensional supermanifold embedded in the (11|32) dimensional target superspace. The kappa-symmetry of the system imposes a constraint on

A. Denner, S. Dittmaier, M. Roth

We study the non-factorizable corrections to W-pair-mediated four-fermion production in ee annihilation in double-pole approximation. We show how these corrections can be combined with the known corrections to the production and the decay of on-shell W-boson pairs, and how the full off-shell Coulomb singularity is included. Moreover, we find that the actual

Siegfried Bethke

A short review of the history and a 'slide-show' of QCD tests in $e^+e^-$ annihilation is given. The world summary of measurements of $α_s$ is updated.

A. A. Penin

We study N=2 supersymmetric Abelian gauge model with the Fayet-Iliopoulos term and an arbitrary number of chiral matter multiplets in two dimensions. By analyzing the instanton contribution we compute the non-perturbative corrections to the mass spectrum of the theory and the quantum deformation of the classical vacua space. In contrast to known examples the

C. B. Yang, X. Cai

It is suggested that the study of multiplicity difference correlators between two well-separated bins in high-energy heavy-ion collisions can be used as a means to detect evidence of a quark-hadron phase transition. Analytical expressions for the scaled factorial moments of multiplicity difference distribution are obtained in a kinetical region ${\bar s}\le

Nobuyoshi Ohta, Takashi Shimizu, Jian-Ge Zhou

The potential between two D4-branes at angles with partially unbroken supersymmetry is computed, and is used to discuss the creation of a fundamental string when two such D4-branes cross each other in M(atrix) theory. The effective Lagrangian is shown to be anomalous at 1-loop approximation, but it can be modified by bare Chern-Simons terms to preserve the i

Christian Bauer

We investigate the two main uncertainties on the extraction of the nonperturbative matrix elements $\barΛ$ and $λ_1$ from moments of the inclusive rare FCNC decay $B \to X_s γ$. The first one is due to unknown matrix elements of higher dimensional operators which are estimated by varying the matrix elements in a range as suggested by dimensional analysis. Th

Jeremy Kepner

Current theories of galaxy formation have tended to focus on hierarchical structure formation, which is the most likely scenario for cosmological models with lots of power at small scales (e.g. standard cold dark matter). Models with little small scale power lead to scenarios closer to spherical collapse. Recently favored power spectra (e.g. CDM+Lambda) lie

Gary T. Horowitz, Emil J. Martinec

The recent suggestion that the entropy of Schwarzschild black holes can be computed in matrix theory using near-extremal D-brane thermodynamics is examined. It is found that the regime in which this approach is valid actually describes black strings stretched across the longitudinal direction, near the transition where black strings become unstable to the fo

E. V. Goldstein, Pierre Meystre

We analyze several models of atomic detectors in the context of the measurement of coherence properties of matter waves. In particular, we show that an ionization scheme measures normally-ordered correlation functions of the Schrödinger field, in analogy with the optical situation. However, it exhibits a sensitivity to exchange processes that is normally abs

Dario A. Estrin, Jorge Kohanoff, Daniel H. Laria, Ruben O. Weht

Monte Carlo simulations using a hybrid quantum and classical mechanical potential were performed for crystal and amorphous-like HCl-water(n) clusters The subsystem composed by HCl and one water molecule was treated within Density Functional Theory, and a classical force field was used for the rest of the system. Simulations performed at 200 K suggest that th

Ulrich H. E. Hansmann

The effectiveness of a new algorithm, parallel tempering, is studied for numerical simulations of biological molecules. These molecules suffer from a rough energy landscape. The resulting slowing down in numerical simulations is overcome by the new method. This is demonstrated by performing simulations with high statistics for one of the simplest peptides, M

A. Gil, J. Nieves, E. Oset

We study the inclusive $(e,e^\prime N)$, $(e,e^\prime NN)$, $(e,e^\prime π)$, $(e,e^\prime πN)$ reactions in nuclei using a Monte Carlo simulation method to treat the multichannel problem of the final state. The input consists of reaction probabilities for the different steps evaluated using microscopical many body methods. We obtain a good agreement with ex

A. Bender, G. I. Poulis, C. D. Roberts, S. Schmidt

In a confining, renormalisable, Dyson-Schwinger equation model of two-flavour QCD we explore the chemical-potential dependence of the dressed-quark propagator, which provides a means of determining the behaviour of the chiral and deconfinement order parameters, and low-energy pion observables. We find coincident, first order deconfinement and chiral symmetry

V. G. J. Stoks

We evaluate the full one-photon-exchange Born amplitude for $Nd$ scattering. We include the contributions due to the magnetic moment of the proton or neutron, and the magnetic moment and quadrupole moment of the deuteron. It is found that the inclusion of the magnetic-moment interaction in the theoretical description of the $Nd$ scattering observables cannot

W. S. Wilburn, C. R. Gould, G. M. Hale, P. R. Huffman

Measurements of the transverse polarization coefficient Kyy' for the reaction 3H(p,n)3He are reported for outgoing neutron energies of 1.94, 5.21, and 5.81 MeV. This reaction is important both as a source of polarized neutrons for nuclear physics experiments, and as a test of theoretical descriptions of the nuclear four-body system. Comparison is made to

Klaus Behrndt

The Bekenstein-Hawking entropy of BPS black holes can be obtained as the minimum of the mass (= largest central charge). In this letter we investigate the analog procedure for the matrix model of M-theory. Especially we discuss the configurations: (i) $2 \times 2 \times 2$ corresponding to the 5-d black hole and (ii) the $5 \times 5 \times 5$ configuration y

Ramon F. Alvarez-Estrada, Angel Gomez Nicola

We study the generating functional for the massless Schwinger model in the torus, at nonzero chemical potential and temperature. The lack of hermiticity of the Dirac operator yields a non-trivial phase in the effective action, which is a topological contribution induced by the chemical potential. In the sector with no zero modes, we evaluate exactly the gene

Dirk Prange

In Causal Perturbation Theory the process of renormalization is precisely equivalent to the extension of time ordered distributions to coincident points. This is achieved by a modified Taylor subtraction on the corresponding test functions. I show that the pullback of this operation to the distributions yields expressions known from Differential Renormalizat

Geza Fulop

We study some reparametrization invariant theories in context of the BRST-co-BRST quantization method. The method imposes restrictions on the possible gauge fixing conditions and leads to well defined inner product states through a gauge regularisation procedure. Two explicit examples are also treated in detail.

Hsien-chung Kao

We calculate the one loop corrections to the Chern-Simons coefficient $κ$ in the Higgs phase of Yang-Mills Chern-Simons Higgs theories. When the gauge group is SU(N), we show, by taking into account the effect of the would be Chern-Simons term, that the corrections are always integer multiples of ${1\over 4π}$, as they should for the theories to be quantum-m

Marijan Ribaric, Luka Sustersic

We propose a new, transport-theoretic (tt) class of relativistic extensions of quantum field theories of fundamental interactions. Its concepts are inspired by Feynman's atomistic idea about the physical world and by the extension of fluid dynamics to shorter distances through the Boltzmann transport equation. The extending tt Lagrangians imply the origi

F. Fucito

The aim of this talk is to give a brief introduction to the problem of confinement in QCD and to N=2 globally supersymmetric Yang-Mills gauge theories (SYM). While avoiding technicalities as much as possible I will try to emphasize the physical ideas which lie behind the picture of confinement as a consequence of the vacua of QCD to be a dual superconductor.

M. V. Polyakov, C. Weiss

We calculate the values of non-factorizable dimension-7 vacuum condensates in the instanton vacuum. We comment on a method, recently proposed by Oganesian, to estimate the dimension-7 condensates by factorization of dimension-10 condensates in various inequivalent ways. The instanton estimates could be used to analyze the stability of QCD sum rules with incr

S. Frankel, W. Frati

The production of J/Psi's in nuclei is re-examined and the critical role of Feynman x distributions in the study of photoproduction and hadronic production of both J/Psi's and Drell-Yan dimuons is expatiated. The need to consider both initial and final state interactions and the key effect of initial state interactions on the total J/Psi cross sectio

A. H. Mueller

A selected review of topics at the border of hard and soft physics is given. Particular emphasis is a placed on diffraction dissociation at Fermilab and HERA. Recently, significant differences between diffraction dissociation at HERA and at Fermilab have become apparent. This may suggest that one already is reaching nonlinear (unitarity) effects which are ex

J. Soffer

We recall the definitions and the basic properties of the transversity distributions $h^{q,\bar q}_1(x,Q^2)$ and the corresponding nucleon tensor charges $δq(Q^2)$. We briefly comment on different estimates from several phenomenological models and on the future possible measurements with the polarized $pp$ collider at RHIC-BNL. Recent works on the $Q^2$-evol

F. Becattini, M. Gazdzicki, J. Sollfrank

The data on average hadron multiplicities in central A+A collisions measured at CERN SPS are analysed with the ideal hadron gas model. It is shown that the full chemical equilibrium version of the model fails to describe the experimental results. The agreement of the data with the off-equilibrium version allowing for partial strangeness saturation is signifi

S. Pepin, Fl. Stancu

We discuss the stability of hexaquark systems of type uuddsQ (Q=c or b) within a chiral constituent quark model which successfully describes the baryon spectra including the charmed ones. We find these systems highly unstable against strong decays and give a comparison with some of the previous literature.

Matteo Cacciari

We review the status of theoretical evaluations of heavy quark and heavy quarkonium hadroproduction cross sections and their comparisons with experimental data.

D. Boer, P. J. Mulders, O. V. Teryaev

We discuss single transverse spin asymmetries in the Drell-Yan process originating from so-called gluonic poles in twist-three hadronic matrix elements, as first considered by Qiu and Sterman. Even though time-reversal invariance is not broken, the effects of such poles cannot be distinguished from those of time-reversal odd distribution functions. We show t

A. G. Rusetsky, M. A. Ivanov, J. G. Korner, V. E. Lyubovitskij

Bethe-Salpeter approach has been applied to the study of b --> c transitions both for heavy mesons and heavy baryons. Meson and baryon IW functions are calculated on the equal footing. A reasonable agreement with the experimental data for heavy to heavy semileptonic transitions has been obtained.

V. E. Lyubovitskij, M. A. Ivanov, J. G. Korner, A. G. Rusetsky

Exclusive nonleptonic decays of bottom and charm baryons are studied within a relativistic quark model. We include factorizing as well as nonfactorizing contributions to the decay amplitudes.

Juan Estrada, Luis Masperi

The present apparent cosmological constant is interpreted as the potential of the lightest pseudo Goldstone boson. Some numerical relations among cosmological parameters and particle masses are shown to arise from the mixture of this very light particle, whose interaction is of the gravitational order, with other pseudo Goldstone bosons like the pion and the

N. V. Krasnikov

Taking into account uncertainties related with the initial coupling constants and threshold corrections at low and high scales we find that in standard supersymmetric SU(5) model the supersymmetry breaking scale could be up to $10^8$ GeV. In the extensions of the standard supersymmetric SU(5) model the supersymmetry breaking scale could be up to $O(10^{12})$

S. Hesselbach, F. Franke, H. Fraas

We study the neutralino mass spectra and production cross sections at an e^+e^- linear collider in superstring-inspired E_6 models. These models are characterized by the existence of new neutral gauge bosons and singlet Higgs fields which also lead to an extended neutralino sector compared to the Minimal Supersymmetric Standard Model (MSSM) or the Next-To-Mi

S. D. Bass, M. M. Brisudova, A. De Roeck

We discuss the potential of polarized HERA to measure the spin dependent part of the total photoproduction cross-section at large $\sqrt{s_{γp}}$.

J. Sato, T. Yanagida

We study a coset-space unification model for families based on $E_7/SU(5) \times U(1)^3$. We find that qualitative structure of quark and lepton mass matrices in this model describes very well the observation. We stress, in particular, that the large mixing angle, $\sin^22θ_{ν_μν_τ} \simeq 1$, required for the atmospheric neutrino oscillation reported by the

K. Terasaki

$\bar B \to Dπ$, $D^*π$, $J/ψ\bar K$ and $J/ψπ$ decays are studied. Their amplitude is given by a sum of factorized and non-factorizable ones. The latter which is estimated by using a hard pion approximation is rather small in color favored $\bar B \to Dπ$ and $D^*π$ decays but still can efficiently interfere with the main amplitude given by the factorizatio

P. Hernandez, Ph. Boucaud

We summarize our recent study of the fermion spectrum in a fermion-scalar 2D model with a chiral $U(1)_L \times U(1)_R$ global symmetry. This model is obtained from a two-cutoff lattice formulation of a 2D U(1) chiral gauge theory, in the limit of zero gauge coupling. The massless fermion spectrum found deep in the vortex phase is undoubled and chiral.

D0 Collaboration

We present a study of Z +gamma + X production in p-bar p collisions at sqrt{S}=1.8 TeV from 97 (87) pb^{-1} of data collected in the eegamma (mumugamma) decay channel with the D0 detector at Fermilab. The event yield and kinematic characteristics are consistent with the Standard Model predictions. We obtain limits on anomalous ZZgamma and Zgammagamma couplin

E. Calzetta, M. Thibeault

The goal of this paper is to provide a new analysis of the classical dynamics of Bianchi type I, II and IX models by applying conventional Hamiltonian methods in the language of Ashtekhar variables. We show that Bianchi type II models can be seen as a perturbation of Bianchi I ones, and integrated. Bianchi IX models can be seen, in turn, as a perturbation of

Orfeu Bertolami

We discuss a mechanism for generating the baryon asymetry of the Universe that involves a putative violation of CPT symmetry arising from string interactions.

Peter C. Aichelburg, Christiane Lechner

We discuss spherically symmetric, static solutions to the SU(2) sigma model on a de Sitter background. Despite of its simplicity this model reflects many of the features exhibited by systems of non-linear matter coupled to gravity e.g. there exists a countable set of regular solutions with finite energy; all of the solutions show linear instability with the

Daniel Ruberman

Mutation is an operation on 3-manifolds containing an embedded surface of genus 2. It is defined by cutting along the surface and regluing using the `hyperelliptic' involution, and is known to preserve many 3-manifold invariants. I show that mutation of a homology 3-sphere preserves its (instanton) Floer homology, and that a related operation on 4-manifo

Johannes Huebschmann

Given a Lie group G whose Lie algebra is endowed with a nondegenerate invariant symmetric bilinear form, we construct a Poisson algebra of continuous functions on a certain open subspace R of the space of representations in G of the fundamental group of a compact connected orientable topological surface with finitely many boundary circles; when G is compact

Paul M. N. Feehan, Thomas G. Leness

We prove the existence of perturbations for the PU(2) monopole equations, yielding transversality on the complement of the anti-self-dual or reducible solutions, and the existence of an Uhlenbeck compactification for the moduli space of solutions to these perturbed PU(2) monopole equations. In December 1994, V. Pidstrigach and A. Tyurin and then others propo

Jan Segert

We present an elementary self-contained account of semisimple Frobenius manifolds in three dimensions, and exhibit a new family of explicit examples. These examples are constructed from Yang-Mills instantons with a certain symmetry.

Plamen Ch. Ivanov, Luis A. N. Amaral, Ary Goldberger, H. Eugene Stanley

We propose a general approach to the question of how biological rhythms spontaneously self-regulate, based on the concept of ``stochastic feedback''. We illustrate this approach by considering the neuroautonomic regulation of the heart rate. The model generates complex dynamics and successfully accounts for key characteristics of cardiac variability,

James A. Feigenbaum, Peter G. O. Freund

Evidence is offered for log-periodic (in time) fluctuations in the S&P 500 stock index during the three years prior to the October 27, 1997 "correction". These fluctuations were expected on the basis of a discretely scale invariant rupture phenomenology of stock market crashes proposed earlier.