November 1999 arXiv papers — page 6

R. E. Borcherds

This is an unpublished manuscript written in 1983-4. It contains several results about lattices (=integral quadratic forms) including the classification of the unimodular lattices in dimensions up to 25 and the construction of unimodular lattices with no roots in dimensions 26 and 27.

Deepak Parashar, Roger J. McDermott

The quantum group G_r,s provides a realisation of the two parameter quantum GL_p,q(2) which is known to be related to the two parameter nonstandard GL_hh'(2) group via a contraction method. We apply the contraction procedure to G_r,s and obtain a new Jordanian quantum group G_m,k. Furthermore, we provide a realisation of GL_h,h'(2) in terms of G_m,k.

Sandra Di Rocco, Andrew J. Sommese

Let $\sE$ be an ample rank $r$ bundle on a smooth toric projective surface, $S$, whose topological Euler characteristic is $e(S)$. In this article, we prove a number of surprisingly strong lower bounds for $c_1(\sE)^2$ and $c_2(\sE)$. We also enumerate the exceptions to either the inequality $c_1(\sE)^2\ge 4e(S)$ or the inequality $c_2(\sE)\ge e(S)$ holding.

Xiaoping Xu

We establish a formal variational calculus of supervariables, which is a combination of the bosonic theory of Gel'fand-Dikii and the fermionic theory in our earlier work. Certain interesting new algebraic structures are found in connection with Hamiltonian superoperators in terms of our theory. In particular, we find connections between Hamiltonian super

Xiaoping xu

In this paper, we construct six families of infinite simple conformal superalgebra of finite growth based on our earlier work on constructing vertex operator superalgebras from graded assocaitive algebras. Three subfamilies of these conformal superalgebras are generated by simple Jordan algebras of types A, B and C in a certain sense.

Bertfried Fauser, Rafal Ablamowicz

Clifford algebras are naturally associated with quadratic forms. These algebras are Z_2-graded by construction. However, only a Z_n-gradation induced by a choice of a basis, or even better, by a Chevalley vector space isomorphism Cl(V) <-> \bigwedge V and an ordering, guarantees a multi-vector decomposition into scalars, vectors, tensors, and so on, mandator

G. Delfino

The study of the scaling limit of two-dimensional models of statistical mechanics within the framework of integrable field theory is illustrated through the example of the RSOS models. Starting from the exact description of regime III in terms of colliding particles, we compute the correlation functions of the thermal, $ϕ_{1,2}$ and (for some cases) spin ope

Musongela Lubo

In this paper we first give arguments supporting the idea that a B.T.Z black hole can face a transplankian problem even when its mass is small. K.M.M quantum theory is applied to the Hawking evaporation of the Schwarzchild and B.T.Z black holes. Working in the physically safe quasi position representation, we argue that the oscillating term present in a prev

Mark Walton

These lecture notes are a brief introduction to Wess-Zumino-Witten models, and their current algebras, the affine Kac-Moody algebras. After reviewing the general background, we focus on the application of representation theory to the computation of 3-point functions and fusion rules.

Kimyeong Lee, Piljin Yi

We explore quantum states of instanton solitons in five dimensional noncommutative Yang-Mills theories. We start with maximally supersymmetric U(N) theory compactified on a circle S^1, and derive the low energy dynamics of instanton solitons, or calorons, which is no longer singular. Quantizing the low energy dynamics, we find N physically distinct ground st

J. Suzuki

The hidden E_{7} (E_{6}) structure has been conjectured for the minimal model ${\cal M}_{4,5} ({\cal M}_{6,7}$) perturbed by $Φ_{1,2}$ in the context of conformal field theory(CFT). Motivated by this, we examine the dilute A_{4, 6} models, which are expected to be corresponding lattice models. Thermodynamics of the equivalent one dimensional quantum systems

Dieter Zeppenfeld

The semileptonic decay of a b-quark, b--> c l nu, is considered in the relativistic limit where the decay products are approximately collinear. Analytic results for the double differential lepton energy distributions are given for finite charm-quark mass. Their use for the fast simulation of isolated lepton backgrounds from heavy quark decays is discussed.

Yoshiaki Yasui

A powerful tool for calculations in non-Abelian gauge theories is obtained by combining the background field gauge, the helicity basis and the color decomposition methods. It has reproduced the one-loop calculation of the five-gluon amplitudes in QCD, is applicable to electroweak processes and extendable to two-loop calculations.

A. Peshier, B. Kampfer, G. Soff

A quasiparticle description of the thermodynamics of deconfined matter, reproducing both the perturbative limit and nonperturbative lattice QCD data at finite temperature, is generalized to finite chemical potential. By a flow equation resulting from Maxwell&#39;s relation, the equation of state is extended from zero to non-zero quark densities. The impact o

A. M. Gago, L. P. Freitas, O. L. G. Peres, R. Zukanovich Funchal

We have investigated the possibility of discerning mass from flavor changing neutrino interactions induced $ν_μ\to ν_τ$ oscillations in the long baseline neutrino experiments K2K and MINOS. We have found that for virtually any value of the flavor conserving parameter $ε^\prime$ it will be possible to, independently, distinguish these two mechanisms at K2K, i

S. V. Goloskokov

Large-distance effects, which lead to the spin-flip part of the hadron -pomeron coupling in QCD -models, are discussed. We study spin asymmetries in exclusive reactions and in diffractive $Q \bar Q$ and vector meson production which are sensitive to the spin-dependent part of the pomeron coupling.

Abdelhak Djouadi

I summarise the virtual effects of the new particles predicted by supersymmetric extensions of the Standard Model on the high-precision electroweak observables measured at LEP/SLC, the Tevatron and CLEO. I will then discuss in some details the two-loop SUSY-QCD corrections to the $ρ$ parameter.

A. Szczurek, V. Uleshchenko

Based on the world DIS data we extract the experimental F_2^p-F_2^n as a function of Bjorken-x and photon virtuality Q^2, using two different methods. Both methods lead to identical results. We find that the standard PDFs fail to describe the experimental data below Q^2 < 7 GeV^2, which is much higher than for F_2^p and F_2^d separately. The difference betwe

Gert Aarts, Bert-Jan Nauta, Chris G. van Weert

The classical approximation provides a non-perturbative approach to time-dependent problems in finite temperature field theory. We study the divergences in hot classical field theory perturbatively. At one-loop, we show that the linear divergences are completely determined by the classical equivalent of the hard thermal loops in hot quantum field theories, a

Alain J. Brizard, Hitoshi Murayama, Jonathan S. Wurtele

A new Lagrangian formalism for self-consistent collective neutrino-plasma interactions is presented in which each neutrino species is described as a classical ideal fluid. The neutrino-plasma fluid equations are derived from a covariant relativistic variational principle in which finite-temperature effects are retained. This new formalism is then used to inv

J. K. Mizukoshi

The CDF preliminary analysis on polarized charmonium production at moderate transverse momentum, $p_T \sim 4 - 20$ GeV, severely challenges the color octet model (COM), which predicts quarkonium to be transversely polarized with increasing $p_T$. Based on this data, we analyze the compatibility of the Tevatron and the photoproduction at HERA in the context o

Marina Artuso

Flavour physics addresses some of the questions for which the Standard Model does not provide a satisfactory and complete answer: the origin of the replication of the fundamental constituents and of their mass hierarchy. This paper reviews some of the theoretical approaches and the experimental strategies that can lead us to a more complete picture. Results

Xiaoping Zheng, Jiarong Li

A double perturbation idea is presented in framework of the quark-gluon plasma kinetic theory. A solvable set of equations from the &#39;double perturbation&#39; is derived and the equations are showed to be gauge-independent. The formalism of Landau damping rate for the plasmon at zero momentum is given and discussed.

Richard C. Brower, Samir D. Mathur, Chung-I Tan

A strong coupling calculation of glueball masses based on the duality between supergravity and Yang-Mills theory is presented. Earlier work is extended to non-zero spin. Fluctuations in the gravitational metric lead to the 2^{++} state on the leading Pomeron trajectory with a mass relation: m(0^{++}) < m(2^{++}) < m(1^{-+}). Contrary to expectation, the mass

J. Engels, T. Mendes

We investigate numerically the three-dimensional O(4) model on 24^3-120^3 lattices as a function of the magnetic field H. We verify explicitly the singularities induced by Goldstone modes in the low-temperature phase of the model, and show that they are also observed close to the critical temperature. Our results are well described by the perturbative form o

E. Perez

Searches for contact interactions, leptoquark bosons and excited fermions carried out at the HERA ep collider are presented here. The searches are based on ~ 40 pb^-1 of e+ p data per experiment collected at a centre of mass energy ~ 300 GeV. First results on e- p data collected in 1998-1999 are also presented.

CMD2 collaboration

A new measurement of the rare decay ϕ\to η&#39; γperformed with the CMD-2 detector at Novosibirsk is described. Of the data sample corresponding to the integrated luminosity of 14.5 pb^{-1}, twenty one events have been selected in the mode η&#39;\toπ^+π^-η, η\toγγ. The following branching ratio was obtained: B(ϕ\to η&#39; γ) = (8.2^{+2.1}_{-1.9} \pm 1.1) 10^

Daniel M. Kaplan

The continued interest of CP violation in hyperon decay (as well as many other physics topics that could be addressed by such a facility) suggests that a dedicated $\bar p$ storage ring at Fermilab ought to be reconsidered. With recent and anticipated technical progress, sensitivity many orders of magnitude beyond that achieved in LEAR may be possible, inclu

Friedrich W. Hehl, Yuri N. Obukhov, Guillermo F. Rubilar

Following Kottler, É.Cartan, and van Dantzig, we formulate the Maxwell equations in a metric independent form in terms of the field strength $F=(E,B)$ and the excitation $H=({\cal D}, {\cal H})$. We assume a linear constitutive law between $H$ and $F$. First we split off a pseudo-scalar (axion) field from the constitutive tensor; its remaining 20 components

Robert M. Wald, Andreas Zoupas

In general relativity, the notion of mass and other conserved quantities at spatial infinity can be defined in a natural way via the Hamiltonian framework: Each conserved quantity is associated with an asymptotic symmetry and the value of the conserved quantity is defined to be the value of the Hamiltonian which generates the canonical transformation on phas

A. M. Gavrilik

After a brief survey of the appearance of quantum algebras in diverse contexts of quantum gravity, we demonstrate that the particular deformed algebras, which arise within the approach of J.Nelson and T.Regge to 2+1 anti-de Sitter quantum gravity (for space surface of genus g) and which are basic for generating the algebras of independent quantum observables

Tiago Charters, Jose P. Mimoso, Ana Nunes

The slow-roll approximation is the usual starting point to study the constraints imposed on the inflaton potential parameters by the observational data. We show that, for a potential exhibiting at least two extrema and giving rise to a limited inflationary period, slow-roll does not have to be taken as an additional hypothesis and is in fact forced by the co

A. Harpaz, N. Soker

The emission of radiation from an accelerated charge is analyzed. It is found that at zero velocity, the radiation emitted from the charge imparts no counter momentum to the emitting charge, and no radiation reaction force is created by the radiation. A reaction force is created by the stress force that exists in the curved electric field of the charge, and

Norimasa Sugiura, Ken-ichi Nakao, Tomohiro Harada

The relation between the angular diameter distance and redshift in a spherically symmetric dust-shell universe is studied. We have discovered that the relation agrees with that of an appropriate Friedmann-Lemaitre (FL) model if we set a ``homogeneous&#39;&#39; expansion law and a ``homogeneous&#39;&#39; averaged density field. This will support the averaging

A. Milchev, J. P. Wittmer, D. P. Landau

An off-lattice Monte Carlo algorithm for solutions of equilibrium polymers (EP) is proposed. At low and moderate densities this is shown to reproduce faithfully the (static) properties found recently for flexible linear EP using a lattice model. The molecular weight distribution (MWD) is well described in the dilute limit by a Schultz-Zimm distribution and b

Ernesto Villar Cocina, Eduardo Valencia Morales, Romulo Gonzalez Rodriguez

The moisture absorption in granulated materials used in foundry technologies is analyzed. The absorption process has a diffusive behavior mainly. A simple experimental technique, in which the wet weight increment was recorded as the experimental parameter and an analytic method with computing procedure to find the parameters characterizing the process was us

D. V. Dmitriev, V. Ya. Krivnov, A. A. Ovchinnikov

A method is proposed for constructing an exact ground-state wave function of a two-dimensional model with spin 1/2. The basis of the method is to represent the wave function by a product of fourth-rank spinors associated with the sites of a lattice and the metric spinors corresponding to bonds between nearest neighbor sites. The function so constructed is an

P. Toth, A. P. Krekhov, L. Kramer, J. Peinke

We investigate the orientational behaviour of a homeotropically aligned nematic liquid crystal subjected to an oscillatory plane Poiseuille flow produced by an alternating pressure gradient. For small pressure amplitudes the director oscillates within the flow plane around the initial homeotropic position, whereas for higher amplitudes a spatially homogeneou

Roland Assaraf, Michel Caffarel

We present a general approach to greatly increase at little cost the efficiency of Monte Carlo algorithms. To each observable to be computed we associate a renormalized observable (improved estimator) having the same average but a different variance. By writing down the zero-variance condition a fundamental equation determining the optimal choice for the ren

D. V. Dmitriev, V. Ya. Krivnov, A. A. Ovchinnikov

We study the spin ladder model with interactions between spins on neighboring rungs. The model Hamiltonian with the exact singlet ground state degenerated with ferromagnetic state is obtained. The singlet ground state wave function has a special recurrent form and depends on two parameters. Spin correlations in the singlet ground state show double-spiral str

J. Vanacken, L. Trappeniers, K. Rosseel, W. Boon

In type II hard superconductors the irreversible magnetization shows an impressive variety of different magnetic field dependencies. In this paper we will try to describe the M(H) relation at fixed temperature To by a numerical model in which we incorporate two features: the magnetic and electric field dependency of the local critical current density j(To,H,

R. Bundschuh

An exact mapping is established between sequence alignment, one of the most commonly used tools of computational biology, and the asymmetric exclusion process, one of the few exactly solvable models of nonequilibrium physics. The statistical significance of sequence alignments is characterized through studying the total hopping current of the discrete time a

A. A. Aligia

We consider the extended Hubbard model with attractive on-site interaction U and nearest-neighbor repulsions V. We construct an effective Hamiltonian H_{eff} for hopping t<<V and arbitrary U<0. Retaining the most important terms, H_{eff} can be mapped onto two XXZ models, solved by the Bethe ansatz. The quantum phase diagram shows two Luttinger liquid phases

S. Michael Fall

This article summarizes - from a personal perspective - some of the main themes that have emerged at this conference and in this field generally in the past few years.

P. de Bernardis, P. A. R. Ade, R. Artusa, J. J. Bock

We describe the BOOMERanG experiment, a stratospheric balloon telescope intended to measure the Cosmic Microwave Background anisotropy at angular scales between a few degrees and ten arcminutes. The experiment has been optimized for a long duration (7 to 14 days) flight circumnavigating Antarctica at the end of 1998. A test flight was performed on Aug.30, 19

Eric R. Tittley, H. M. P. Couchman

The baryon fraction of galaxy clusters in numerical simulations is found to be dependant on the cluster formation method. In all cases, the gas is anti-biased compared with the dark matter. However, clusters formed hierarchically are found to be more depleted in baryons than clusters formed non-hierarchically. There is a depletion of 10 to 15% for hierarchic

D. Calzetti, L. Armus, R. C. Bohlin, A. L. Kinney

(Abridged) We present far-infrared (FIR) photometry at 150 micron and 205 micron of eight low-redshift starburst galaxies obtained with the ISO Photometer. Five of the eight galaxies are detected in both wavebands and these data are used, in conjunction with IRAS archival photometry, to model the dust emission at lambda>40 micron. The FIR spectral energy dis

G. E. Brown, C. -H. Lee, H. K. Lee, H. A. Bethe

We suggest Nova Sco 1994 (GRO 1655-40) as a possible relic of a Gamma Ray Burster (GRB) and Type Ib supernova (SN) explosion, showing that there is evidence both that the black hole was spun up by accretion and that there was a supernova explosion. We use the disc energy delivered from the rotational energy of the black hole to power the SN, and give argumen

A. Merloni, A. C. Fabian, R. R. Ross

We present a critical analysis of the usual interpretation of the multicolour disc model parameters for black hole candidates in terms of the inner radius and temperature of the accretion disc. Using a self-consistent model for the radiative transfer and the vertical temperature structure in a Shakura-Sunyaev disc, we simulate the observed disc spectra, taki

Martin Altmann, Klaas S. de Boer

Field Horizontal branch (HB) stars can be used as tracers for the study of early stages of the evolution of our galaxy. Since the age of individual HB stars is not known a priori, we have studied the kinematics of a sample of field HB stars measured with Hipparcos to look for signs of age and population nature. We found that the kinematics of the HBA stars i

P. Richter, K. S. de Boer, H. Widmann, N. Kappelmann

We report the discovery of molecular hydrogen absorption in a Galactic high-velocity cloud (HVC) in the direction of the Large Magellanic Cloud. For the same HVC we derive an iron abundance which is half of the solar value. Thus, all evidence points to a Galactic origin for high-velocity cloud complex in front of the LMC.

E. Ros, J. A. Zensus, A. P. Lobanov

We have studied the parsec-scale structure of the quasar 3C345 at λλ1.3, 2, 3.6, and 6 cm, using total intensity and linear polarization images from 3 epochs of VLBA observations made in 1995.84, 1996.41, and 1996.81. The images show an unresolved &#34;core&#34; and a radio jet extending over distances up to 25 milliarcseconds. At 1.3 and 2 cm, images of the

Aaron Golden, Andy Shearer, Gregory Beskin

Using the high speed 2-d TRIFFID photometer, we have obtained phase resolved photometry of the Crab pulsar in UBV that allows us to flux the unpulsed light curve component. Following de-extinction, weighted least-square fitting indicates a power-law exponent of alpha = -0.62 +/- 0.49. This is steeper than that reported for the peak components and its origin

Martin Pohl, Reinhard Schlickeiser

It has been suggested that relativistic blast waves may power the jets of AGN and gamma-ray bursts (GRB). We address the important issue how the kinetic energy of collimated blast waves is converted into radiation. It is shown that swept-up ambient matter is quickly isotropised in the blast wave frame by a relativistic two-stream instability, which provides

Aaron Golden, Andy Shearer, Jerry Edelstein

PSR B0656+14&#39;s high energy emission is consistent with that of combined magnetospheric and thermal (surface & polar cap) emission. Uncertainties with the radio-derived distance and X-ray instrumentation sensitivities complicate a definitive thermal characterisation however. A re-analysis of combined ROSAT/EUVE archival data in conjunction with integrated

M. Arnould, G. Meynet, N. Mowlavi

Radionuclides with half-lives ranging from some years to billions of years presumably synthesized outside of the solar system are now recorded in `live&#39; or `fossil&#39; form in various types of materials, like meteorites or the galactic cosmic rays. They bring specific astrophysical messages the deciphering of which is briefly reviewed here, with special

Andrew W. Blain

The importance of the Atacama Large Millimeter Array (ALMA) to the study of high-redshift dusty gas-rich galaxies is described. ALMA will have dramatically greater sensitivity and angular resolution than existing millimetre(mm) and submm-wave telescopes. Two key areas are emphasized: i) extremely deep galaxy surveys down to flux densities of about 10 microJy

Ryoichi Nishi, Hideyuki Kamaya

Dynamical stability of the shock compressed layer with finite thickness is investigated. It is characterized by self-gravity, structure, and shock condition at the surfaces of the compressed layer. At one side of the shocked layer, its surface condition is determined via the ram pressure, while at the other side the thermal pressure supports its structure. W

Martin G. Haehnelt, Matthias Steinmetz, Michael Rauch

We combine predictions for several hierarchical cosmogonies with observational evidence on damped Lyman alpha systems to establish a correspondence between the high redshift galaxy population and the properties of damped Lyman alpha systems. We assume that high redshift galaxies and damped Lyman alpha systems are hosted by the same dark matter halos and requ

K. A. Weaver, T. Heckman, M. Dahlem

(abbreviated) We have undertaken an X-ray survey of a far-infrared flux limited sample of seven nearby edge-on starburst galaxies. Here, we examine the two X-ray-brightest sample members NGC 253 and M 82 in a self-consistent manner, taking account of the spatial distribution of the X-ray emission in choosing our spectral models. There is significant X-ray ab

P. D. Mauskopf, P. A. R. Ade, P. de Bernardis, J. J. Bock

We describe a measurement of the angular power spectrum of anisotropies in the Cosmic Microwave Background (CMB) from 0.3 degrees to ~10 degrees from the North American test flight of the BOOMERANG experiment. BOOMERANG is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a Long Duration Balloon flight. During a 6-hour

I. H. Stairs, S. E. Thorsett, J. H. Taylor, Z. Arzoumanian

We present Arecibo observations of PSR B1534+12 which confirm previous suggestions that the pulse profile is evolving secularly. This effect is similar to that seen in PSR B1913+16, and is almost certainly due to general relativistic precession of the pulsar&#39;s spin axis.

Atsushi Kawai, Toshiyuki Fukushige, Junichiro Makino

As an entry for the 1999 Gordon Bell price/performance prize, we report an astrophysical N-body simulation performed with a treecode on GRAPE-5 (Gravity Pipe 5) system, a special-purpose computer for astrophysical N-body simulations. The GRAPE-5 system has 32 pipeline processors specialized for the gravitational force calculation. Other operations, such as t

Frank Schweitzer

We propose a stochastic dynamic model of migration and economic aggregation in a system of employed (immobile) and unemployed (mobile) agents which respond to local wage gradients. Dependent on the local economic situation, described by a production function which includes cooperative effects, employed agents can become unemployed and vice versa. The spatio-

Lior M. Burko

We overview the recently proposed mode-sum regularization prescription (MSRP) for the calculation of the local radiation-reaction forces, which are crucial for the orbital evolution of binaries. We then describe some new results which were obtained using MSRP, and discuss their importance for gravitational-wave astronomy.

Nikhil Padmanabhan, Max Tegmark, Andrew J. S. Hamilton

The combined CfA2/SSRS redshift catalog has recently been improved and made public. We compute the redshift-space power spectrum of this catalog using the regions at -2.5 < delta < 50 north (8h < alpha < 17h) and south (20h < alpha < 3h, b < -13) of the Galactic plane, where it is 98% complete down to Zwicky magnitude 15.5 and contains 13,681 galaxies. Our a

Chi-Keung Chow, Thomas D. Cohen

We discuss counterintuitive aspects of probabilities for systems of identical particles obeying quantum statistics. Quantum coins and children (two level systems) and quantum dice (many level systems) are used as examples. It is emphasized that, even in the absence of interactions, (anti)symmetrizations of multi-particle wavefunctions destroy statistical ind

Walter D. Goldberger, Mark B. Wise

We explore the phenomenology of a stabilized modulus field in the Randall-Sundrum scenario. It is found that if the large separation between branes arises from a small bulk scalar mass then the modulus (i.e. radion) is likely to be lighter than the lowest Kaluza-Klein excitations of bulk fields, and consequently may be the first direct signature of the model

Lowell S. Brown, Laurence G. Yaffe

We examine the equilibrium properties of hot, dilute, non-relativistic plasmas. The partition function and density correlation functions of a classical plasma with several species are expressed in terms of a functional integral over electrostatic potential distributions. The leading order, field-theoretic tree approximation automatically includes the effects

John Ellis, M. E. Gomez, G. K. Leontaris, S. Lola

Motivated by the data from Super-Kamiokande and elsewhere indicating oscillations of atmospheric and solar neutrinos, we study charged-lepton-flavour violation, in particular the radiative decays mu -> e gamma and tau -> mu gamma, but also commenting on mu -> 3e and tau -> 3 mu/e decays, as well as mu - e conversion on nuclei. We first show how the renormali

Ali Kaya

The classical cross section for low energy absorption of the RR-scalar by a stack of noncommutative D3-branes in the large NS B-field limit is calculated. In the spirit of AdS/CFT correspondence, this cross section is related to two point function of a certain operator in noncommutative Yang-Mills theory. Compared at the same gauge coupling, the result agree

Branko P. Stojkovic, Z. G. Yu, A. L. Chernyshev, A. R. Bishop

The competition between long-range and short-range interactions among holes moving in an antiferromagnet (AF), is studied within a model derived from the spin density wave picture of layered transition metal oxides. A novel numerical approach is developed which allows one to solve the problem at finite hole densities in very large systems (of order hundreds

Dan N. Vollick

In this paper a general solution is found for a five dimensional orbifold spacetime that induces a $k=0$ cosmology on a three-brane. Expressions for the energy density and pressure on the brane in terms of the brane metric are derived. Given a metric on the brane it is possible to find five dimensional spacetimes that contain the brane. This calculation is c

Stephan Narison

I give a short historical and a critical review of the determinations of light quark masses from QCD at dawn of the next millennium. QCD spectral sum rules combined with ChPT give, to order $\alpha_s^3$, the world average for the running masses: $\bar{m}_s$(2 GeV)= $(118.9\pm 12.2)$ MeV, $\bar{m}_d(2~{GeV})=(6.3\pm 0.8)$ MeV, $\bar{m}_u(2~{GeV})=(3.5\pm 0.4)

Stefan Leupold

Aiming at a description of transport processes where the dynamically generated width of the states is potentially large a transport equation beyond the quasiparticle approximation is derived in first order gradient expansion. An effective particle number is identified which is exactly conserved by the coarse grained transport equation. Using a test particle

Chunsheng Ban, Lee J. McEwan, András Némethi

The goal of this paper is the presentation of an ``embedded resolution&#39;&#39; of ({f(x,y)+z^2=0},0) \subset (C^3,0) using the method of Jung.

R. Bonifacio, S. Olivares, P. Tombesi, D. Vitali

We consider the case when decoherence is due to the fluctuations of some classical variable or parameter of a system and not to its entanglement with the environment. Under few and quite general assumptions, we derive a model-independent formalism for this non-dissipative decoherence, and we apply it to explain the decoherence observed in some recent experim

A. H. Chamseddine, W. A. Sabra

The theory of SU(2) gauged seven-dimensional supergravity is obtained by compactifying ten dimensional N=1 supergravity on the group manifold SU(2).

Julien Lesgourgues

Recently, there has been some interest for building supersymmetric models of double inflation. These models, realistic from a particle physics point of view, predict a broken-scale-invariant power spectrum of primordial cosmological perturbations, that may explain eventual non-trivial features in the present matter power spectrum. In previous works, the prim

A. S. Alexandrov, C. Sricheewin

According to recent Quantum Monte Carlo simulations the small polaron theory is practically exact in a wide range of the long-range (Frohlich) electron-phonon coupling and adiabatic ratio. We apply the Lang-Firsov transformation to convert the strong-coupling term in the Hamiltonian into the form of an effective hopping integral and derive the single-particl

M. Fischer, S. Groote, J. G. Körner, M. C. Mauser

The dominant contribution to the inclusive decays of $B$ mesons into the charm-strangeness mesons $D_s$ and $D_s^{\ast}$ is expected to be given by the partonic process $b \to c+(D_s^-,D_s^{\ast -})$. We determine the nonperturbative $O(1/m_b^2)$ and the $O(α_s)$ radiative corrections to $b \to c+(D_s^-,D_s^{\ast -})$ and thereby to the inclusive decays $ \b

H. R. Christiansen, A. C. Petkou, M. B. Silva Neto, N. D. Vlachos

We study the thermodynamics of the 2+1 dimensional Gross-Neveu model in the presence of a chemical potential by introducing a representation for the canonical partition function which encodes both real and imaginary chemical potential cases. It is pointed out that the latter case probes the thermodynamics of the possible anyon-like excitations in the spectru

M. Aunola, J. J. Toppari, J. P. Pekola

The Hamiltonian operator for an unbiased array of Josephson junctions with gate voltages is constructed when only Cooper pair tunnelling and charging effects are taken into account. The supercurrent through the system and the pumped current induced by changing the gate voltages periodically are discussed with an emphasis on the inaccuracies in the Cooper pai

T. D. Palev, J. Van der Jeugt

For the Lie superalgebra $q(n+1)$ a description is given in terms of creation and annihilation operators, in such a way that the defining relations of $q(n+1)$ are determined by quadratic and triple supercommutation relations of these operators. Fock space representations $V_p$ of $q(n+1)$ are defined by means of these creation and annihilation operators. Th

Jens Lieberum

We define the Conway skein module C(M) of ordered based links in a 3-manifold M. This module gives rise to C(M)-valued invariants of usual links in M. We determine a basis of the Z[z]-module C(F x [0,1])/Tor(C(F x [0,1])) where F is the real projective plane or a surface with boundary. For cylinders over the Moebius strip or the projective plane we derive sp

Gu Xu, Dingzhou Li, Bingshen Wang, Zhao-bin Su

We present a comprehensive theoretical description of quantum well exciton-polaritons imbedded in a planar semiconductor microcavity. The exact non-local dielectric response of the quantum well exciton is treated in detail. The 4-spinor structure of the hole subband in the quantum well is considered, including the pronounced band mixing effect. The scheme is

D. Rusin, P. B. Hall, R. C. Nichol, D. R. Marlow

We present adaptive optics imaging of the CLASS gravitational lens system B1359+154 obtained with the Canada-France-Hawaii Telescope (CFHT) in the infrared K band. The observations show at least three brightness peaks within the ring of lensed images, which we identify as emission from multiple lensing galaxies. The results confirm the suspected compound nat

S. M. Lietti

The Standard Model (SM) of the electroweak has proven to be successful in describing all the available precision experimental data. However, the Higgs mechanism, responsible for the electroweak symmetry breaking in the SM, still remains one of the most important open questions of the theory. The effect of new operators that give rise to anomalous Higgs boson

A. A. Kornyshev, S. Leikin

We derive formulae for the electrostatic interaction between two long, rigid macromolecules that may have arbitrary surface charge patterns and cross at an arbitrary interaxial angle. We calculate the dependence of the interaction energy on the interaxial angle, on the separation, and on the precise alignment of the charge pattern on one molecule with respec

Oliver T. Dasbach, Brian S. Mangum

In a recent paper, McMullen showed an inequality between the Thurston norm and the Alexander norm of a 3-manifold. This generalizes the well-known fact that twice the genus of a knot is bounded from below by the degree of the Alexander polynomial. We extend the Bennequin inequality for links to an inequality for all points of the Thurston norm, if the manifo

Aurel Bulgac, Giu Do Dand, Dimitri Kusnezov

We present a microscopic approach to quantum dissipation and sketch the derivation of the kinetic equation describing the evolution of a simple quantum system in interaction with a complex quantum system. A typical quantum complex system is modeled by means of parametric banded random matrices coupled to the subsystem of interest. We do not assume the weak c

Alexander Yu. Vlasov

In classical case there is simplest method of error correction with using three equal bits instead of one. In the paper is shown, how the scheme fails for quantum error correction with complex vector spaces of usual quantum mechanics, but works in real and quaternionic cases. It is discussed also, how to implement the three qubits scheme with using encoding

Sadhan K. Adhikari, P. K. Biswas

The scattering of ortho-positronium (Ps) by hydrogen atoms has been investigated in a five-state coupled-channel model allowing for Ps(1s)H(2s,2p) and Ps(2s,2p)H(1s) excitations using a recently proposed electron-exchange model potential. The higher ($n\ge 3$) excitations and ionization of the Ps atom are calculated using the first Born approximation. Calcul

Sadhan K. Adhikari, P. K. Biswas, R. A. Sultanov

Very low-energy scattering of orthopositronium by helium has been investigated for simultaneous study of elastic cross section and pick-off quenching rate using a model exchange potential. The present calculational scheme, while agrees with the measured cross section of Skalsey et al, reproduces successfully the parameter $^ 1Z_{\makebox{eff}}$, the effectiv

P. K. Biswas, Sadhan K. Adhikari

The formulation of a suitable nonlocal model potential for electron exchange is presented, checked with electron-hydrogen and electron-helium scattering, and applied to the study of elastic and inelastic scattering and ionization of ortho positronium (Ps) by helium. The elastic scattering and the $n = 2$ excitations of Ps are investigated using a three-Ps-st

M. I. Mazhitov, Yu. A. Serebrennikov

The stochastic Liouville method is used to analyze the general problem of spin-lattice relaxation in zero-field for molecules undergoing Markovian reorientations.

H. J. Kim, S. K. Kim, S. H. Lee, T. W. Hur

We have developed a fast programmable trigger processor board based on a field programmable gate array and a complex programmable logic device for use in the BELLE experiment. The trigger board accommodates 144 ECL input signals, 2 NIM input signals, 24 ECL output signals, and the VME bus specification. An asynchronous trigger logic for counting isolated clu

J. L. Friar

Twenty-five years ago the International Few-Body Conference was held in Quebec City. It became very clear at that meeting that the theoretical situation concerning the He3 and H3 ground states was confused. A lack of computational power prevented converged brute-force solutions of the Faddeev or Schroedinger equations, both for bound and continuum states of

Afsar Abbas

It is shown that the hole in the centre of $ ^{3}H $, $ ^{3}He $ and $ ^{4}He $, the neutron halos in nuclei, the $ α- $ and other clustering effects in nuclei and the nuclear molecules all basically arise due to the same underlying effect. We shall show that all these ground state properties of nuclei are manifestations of quark effects. The role of triton

D. Ebert, K. G. Klimenko

The phase structure of a simple Nambu-Jona-Lasinio model has been investigated at non-zero values of $μ$ and H, where H is an external magnetic field and $μ$ is the chemical potential. On this basis magnetic oscillations effects were considered. It was shown that there are standard (periodic) van Alphen-de Haas magnetic oscillations of some thermodynamical q