October 1997 arXiv papers — page 16

David Dooling, Kyungsik Kang, Sin Kyu Kang

We present lower bounds on the Higgs boson mass in the Standard Model with three and four fermion generations SM(3,4), as well as upper bounds on the lightest Higgs boson mass in the minimal supersymmetric extension of the SM with three and four generations MSSM(3,4). Our analysis utilizes the SM(3,4) renormalization-group-improved one-loop effective potenti

Todd A. Brun

Quantum open systems are described in the Markovian limit by master equations in Lindblad form. I argue that common ``quantum trajectory'' techniques corresponding to continuous measurement schemes, which solve the master equation by unraveling its evolution into stochastic trajectories in Hilbert space, correspond closely to particular sets of decoh

Alexander Turbiner

Two Lie algebraic forms of the 2-body Elliptic Calogero model are presented. Translation-invariant and dilatation-invariant discretizations of the model are obtained.

V. V. Konotop, M. Salerno, S. Takeno

We use SU(2) coherent state path integral formulation with the stationary phase approximation to investigate, both analytically and numerically, the existence of shock waves in the one- dimensional Heisenberg ferromagnets with anisotropic exchange interaction. As a result we show the existence of shock waves of two types,"bright" and "dark",

Stefan Weigert

Multiplication of two elements of the special unitary group SU(N) determines uniquely a third group element. A BAker-Campbell-Hausdorff relation is derived which expresses the group parameters of the product (written as an exponential) in terms of the parameters of the exponential factors. This requires the eigen- values of three (N-by-N) matrices. Consequen

G. Vilasi

Canonical coordinates for both the Schroedinger and the nonlinear Schroedinger equations are introduced, making more transparent their Hamiltonian structures. It is shown that the Schroedinger equation, considered as a classical field theory, shares with the nonlinear Schroedinger, and more generally with Liouville completely integrable field theories, the e

Alexander Turbiner

A catalogue of explicit realizations of representations of (super) Lie algebras and quantum algebras in Fock space is presented.

B. Segev, J. C. Wells

We perform a gauge-transformation on the time-dependent Dirac equation describing the evolution of an electron in a heavy-ion collision to remove the explicit dependence on the long-range part of the interaction. We solve, in an ultra-relativistic limit, the gauged-transformed Dirac equation using light-front variables and a light-fronts representation, obta

D. Flamm

In two respects Ludwig Boltzmann was a pioneer of quantum mechanics. First because in his statistical interpretation of the second law of thermodynamics he introduced the theory of probability into a fundamental law of physics and thus broke with the classical prejudice, that fundamental laws have to be strictly deterministic. Even Max Planck had not been re

S. A. Fulling

It is well known that short-time expansions of heat kernels correlate to formal high-frequency expansions of spectral densities. It is also well known that the latter expansions are generally not literally true beyond the first term. However, the terms in the heat-kernel expansion correspond rigorously to quantities called Riesz means of the spectral expansi

J. N. De, S. K. Samaddar, S. Shlomo

In a finite temperature Thomas-Fermi framework, we calculate density distributions of hot nuclei enclosed in a freeze-out volume of few times the normal nuclear volume and then construct the caloric curve, with and without inclusion of radial collective flow. In both cases, the calculated specific heats $C_v$ show a peaked structure signalling a liquid-gas p

E. G. Floratos, G. K. Leontaris

In this work we study the recently introduced octonionic duality for membranes. Restricting the self - duality equations to seven space dimensions, we provide various forms for them which exhibit the symmetries of the octonionic and quaternionic structure. These forms may turn to be useful for the question of the integrability of this system. Introducing a c

Gerald Dunne, Theodore M. Hall

We compute the exact QED_{3+1} effective action for fermions in the presence of a family of static but spatially inhomogeneous magnetic field profiles. An asymptotic expansion of this exact effective action yields an all-orders derivative expansion, the first terms of which agree with independent derivative expansion computations. These results generalize an

R. J. Henderson, S. G. Rajeev

We obtain for the attractive Dirac delta-function potential in two-dimensional quantum mechanics a renormalized formulation that avoids reference to a cutoff and running coupling constant. Dimensional transmutation is carried out before attempting to solve the system, and leads to an interesting eigenvalue problem in N-2 degrees of freedom (in the center of

R. Banerjee, C. Wotzasek

We develop a systematic method of obtaining duality symmetric actions in different dimensions. This technique is applied for the quantum mechanical harmonic oscillator, the scalar field theory in two dimensions and the Maxwell theory in four dimensions. In all cases there are two such distinct actions. Furthermore, by soldering these distinct actions in any

Sahng-Kyoon Yoo, D. K. Park

Evaluating the propagator by the usual time-sliced manner, we use it to compute the second virial coefficient of an anyon gas interacting through the repulsive potential of the form $g/r^2 (g > 0)$. All the cusps for the unpolarized spin-1/2 as well as spinless cases disappear in the $ω\to 0$ limit, where $ω$ is a frequency of harmonic oscillator which is in

Mohamed Benarous

The time-dependent variational principle proposed by Balian and Veneroni is used to provide the best approximation to the generating functional for multi-time Green's functions of a set of (bosonic) observables $Q_{μ)$. By suitably restricting the trial spaces, the computation of the two-time Green's function, obtained by a second order expansion in

Yuval Grossman

In supersymmetric models with nonvanishing Majorana neutrino masses, the sneutrino and antisneutrino mix. The conditions under which this mixing is experimentally observable are studied, and mass-splitting of the sneutrino mass eigenstates and sneutrino oscillation phenomena are analyzed.

A. N. Kamal, C. W. Luo

The role of inelastic final-state interactions in CP asymmetries and branching ratios is investigated in certain chosen single isospin two-body hadronic B decays. Treating final-state interactions through Pomeron and Regge exchanges, we demonstrate that inelastic final state interactions could lead to sizeable effects on the CP asymmetry.

Erich Poppitz

This theoretical review is intended to give non-theorists a flavor of the ideas driving the current efforts to experimentally find supersymmetry. We discuss the main reasons behind the expectation that supersymmetry may be "just around the corner" and may be discovered in the near future. We use simple quantum-mechanical examples to illustrate the co

M. Grazzini

Cut vertices, a generalization of matrix elements of local operators, are revisited, and an expansion in terms of minimally subtracted cut vertices is formulated. An extension of the formalism to deal with semi-inclusive deep inelastic processes in the target fragmentation region is explicitly constructed. The problem of factorization is discussed in detail.

T. S. Evans, H. F. Jones, A. Ritz

The phase structure of the 3D SU(2)--Higgs model, the dimensionally reduced effective theory for the electroweak model at finite temperature, is analysed on the lattice using a variant of the linear $\de$--expansion. We develop a systematic variational cumulant expansion for general application to the study of gauge invariant operators in 3D gauge-Higgs mode

V. Yu. Petrov, P. V. Pobylitsa, M. V. Polyakov, I. Boernig

We study the off-forward quark distributions (OFQD's) in the chiral quark-soliton model of the nucleon. This model is based on the large-N_c picture of the nucleon as a soliton of the effective chiral lagrangian and allows to calculate the leading twist quark- and antiquark distributions at a low normalization point. We demonstrate the consistency of the

M. A. Braun, V. V. Vechernin

The deuteron disintegration process with the emission of fast proton in the vicinity of the kinematical boundary of the reaction, when Feynman variable $x\to 2$, is studied. The consideration is fulfilled in the framework of the quark-parton model of cumulative phenomena based on perturbative QCD calculations of the corresponding quark diagrams near the thre

P. Herrera-Siklódy, J. I. Latorre, P. Pascual, J. Taron

We obtain explicit expressions for the ηand η' masses and decay constants using U_L(3) x U_R(3) chiral perturbation theory at next-to-leading order in a combined expansion in p^2 and 1/Nc. A numerical fit of the parameters appearing to this order of the expansion is also discussed.

Jaume Guasch

We compute the partial width of the FCNC top quark decay t->c h in the framework of the Minimal Supersymmetric Standard Model, where h = h0, H0, A0 is any of the neutral Higgs of the MSSM. We include the SUSY electroweak, Higgs, and SUSY-QCD contributions. Our results substantially improve previous estimations on the subject, and we find that there is a poss

A. Bravar, D. von Harrach, A. Kotzinian

We propose to measure the gluon distribution function Delta G(eta) at eta < 0.2 via pseudo jet production in polarized fixed target lepton nucleon scattering at typical lepton beam energies of 200 GeV. The measurement of the spin-asymmetry for the production of correlated charge conjugated hadrons of opposite transverse momentum can be directly related to De

T. Bahnik

Tree-level scattering amplitudes of longitudinally polarized electroweak vector bosons in the Standard Model are calculated using Mathematica package Feyncalc. The modifications of low-energy theorems for longitudinally polarized W and Z in the Standard Model are discussed.

Jan Stern

Consequences of the alternative mechanism of spontaneous breaking of chiral symmetry without formation of a large quark antiquark condensate is reviewed. Emphasis is put on the resulting picture of light quark masses.

Mikhail Braun, Daniele Treleani

The inclusive production of several jets is studied in the framework of the hard pomeron model. The average jet momenta are found to be strongly ordered and growing towards the central c.m. rapidity, as expected. Strong positive correlations are found for pairs of jets neighbouring in rapidity, both in the forward-backward and forward-forward directions.

Subhendra Mohanty, Sarira Sahu

The helicity changing Cerenkov radiation in a supernova core was used earlier to put a restrictive bound on the neutrino magnetic moment. Subsequently it was pointed out, that this result was based on a numerical error in the calculationn of the refractive index of the SN core and using the correct numbers it was shown that the photons in a SN core do not ha

I. V. Musatov, O. V. Teryaev, A. Schäfer

The elastic contribution to the first moment of $g_2(x,Q^2)$ is analysed using a Drell-Yan-West type of relation and is shown to be negative. For a qualitative estimate the one-loop contributions to the polarized DIS sum rules in QED are studied. The behaviour of the generalized Gerasimov-Drell-Hearn sum rule is sensitive to infrared regularization. With a l

M. A. Valle Basagoiti

A calculation is presented of the plasmon and photon damping rates in a dense nonrelativistic plasma at zero temperature, following the resummation program of Braaten-Pisarski. At small soft momentum $k$, the damping is dominated by $3 \to 2$ scattering processes corresponding to double longitudinal Landau damping. The dampings are proportional to $(α/v_{F})

Mike Peardon

A review of new results from lattice simulations of glueballs and heavy-quark hybrid mesons is presented.

Hideo Nakajima, Sadataka Furui

The 2nd order Runge-Kutta scheme Langevin simulation of unquenched QCD in pseudofermion method derived from our general theory shows a behaviour as a function of the Langevin step t better than the Fukugita,Oyanagi,Ukawa&#39;s scheme.

Maurice H. P. M. van Putten

The prime candidate of LIGO/VIRGO sources of gravitational waves is the spiral in of black holes and neutron stars in compact binaries. While the early stages of the evolution of compact binaries is computable from post-Newtonian calculations, prediction of their late stages requires large scale numerical simulation. A fully covariant and strictly hyperbolic

A. Błaut, J. Kowalski-Glikman

We construct the regularised Wheeler-De Witt operator demanding that the algebra of constraints of quantum gravity is anomaly free. We find that for a subset of all wavefunctions being integrals of scalar densities this condition can be satisfied. We proceed to finding exact solutions of quantum gravity being of the form of functionals of volume and average

Luc Blanchet

This paper investigates the non-linear self-interaction of quadrupole gravitational waves generated by an isolated system. The vacuum Einstein field equations are integrated in the region exterior to the system by means of a post-Minkowskian algorithm. Specializing in the quadrupole-quadrupole interaction (at the quadratic non-linear order), we recover the k

O. Bertolami, P. D. Fonseca, P. V. Moniz

We study solutions of the Wheeler-DeWitt equation obtained when considering homogeneous and isotropic (up to a gauge transformation) field configurations of the Einstein-Yang-Mills system in $D=4+d$ dimensions with an $R \times S^3 \times S^d$ topology and assuming the Hartle-Hawking boundary conditions.

J. Hwang, H. Noh

We analyse the evolution of the rotational type cosmological perturbation in a gravity with general quadratic order gravitational coupling terms. The result is expressed independently of the generalized nature of the gravity theory, and is simply interpreted as a conservation of the angular momentum.

Janusz Grabowski, Pawel Urbanski

Poisson-NIjenhuis structures for an arbitrary Lie agebroid are defined and studied by means of tangent lifts of tensor fields.

W. Ding, J. Jost, J. Li, G. Wang

Extending work of Caffarelli-Yang and Tarantello, we present a variational existence proof for two-vortex solutions of the periodic Chern-Simons Higgs model and analyze the asymptotic behavior of these solutions as the parameter coupling the gauge field with the scalar field tends to 0.

W. Ding, J. Jost, J. Li, G. Wang

Let $M$ be a compact Riemann surface, $h(x)$ a positive smooth function on $M$. In this paper, we consider the functional $$J(u)={1/2}\int \sb{M}|\bigtriangledown u|\sp 2 + 8π\int\sb{M}u -8π\log\int\sb{M}h\exp {u}$$. We give a sufficient condition under which $J$ achieves its minimum.

Denjoe O&#39;Connor, C. R. Stephens

Based on renormalization group arguments we establish that for a superconductor in the presence of a weak external magnetic field, $B$, the dependence on $B$ and the deviation from the critical temperature, $τ$, of a thermodynamic quantity, $P$, takes the scaling form $P=t^θX({B\overΦ_0}τ^{-2ν},qτ^{-νω_e})$, where $θ$ and $ν$ are XY exponents, $q$ is the sca

A. Vazquez, O. Sotolongo-Costa, F. Brouers

The relaxation in complex systems is in general nonexponential. After an initial rapid decay the system relax slowly following a long time tail. In the present paper a sandpile modelation of the relaxation in complex systems is analysed. Complexity is introduced by a process of avalanches in the Bethe lattice and a feedback mechanism which leads to slower de

A. Baumgärtner, U. Ebert, L. Schäfer

We present simulation data for the motion of a polymer chain through a regular lattice of impenetrable obstacles (Evans-Edwards model). Chain lengths range from N=20 to N=640, and time up to $10^{7}$ Monte Carlo steps. For $N \geq 160$ we for the central segment find clear $t^{1/4}$-behavior as an intermediate asymptote. The also expected $t^{1/2}$-range is

Hans-Benjamin Braun, Jordan Kyriakidis, Daniel Loss

Quantum tunneling of domain walls out of an impurity potential in a mesoscopic ferromagnetic sample is investigated. Using improved expressions for the domain wall mass and for the pinning potential, we find that the cross-over temperature between thermal activation and quantum tunneling is of a different functional form than found previously. In materials l

H. Mayaffre, P. Auban-Senzier, D. Jérome, D. Poilblanc

Transport and 63^Cu-NMR, Knight shift and T_1, measurements performed on the two-leg spin ladders of Sr_2Ca_{12}Cu_{24}O_{41} single crystals show a collapse of the gap in ladder spin excitations when superconductivity is stabilised under a pressure of 29 kbar. These results support the prediction made with exact diagonalisation techniques in two-leg isotrop

Oleg Tchernyshyov

I present an exactly solvable model of a pseudogap with two zero-energy fermion modes coupled to each other by a classical source of frequency omega_0 and strength |Delta|. A suitably defined fermion propagator has an infinite number of poles at frequencies that are multiple integers of omega_0. In the adiabatic limit, omega_0 << |Δ|, the situation is qualit

Colin Denniston, Chao Tang

To examine the properties of the frustrated XY model at an incommensurate field we have examined a sequence of magnetic filling factors f which approach the irrational value of one minus the golden mean. At all f studied, the system undergoes a finite-temperature weak first-order transition involving the freezing out of Ising-like domain walls. As one approa

V. J. Emery, S. A. Kivelson

High temperature superconductivity is a property of doped antiferromagnetic insulators. The electronic structure is inhomogeneous on short length and time scales, and, as the temperature decreases, it evolves via two crossovers, before long range superconducting order is achieved. Except for overdoped materials, pairing and phase coherence occur at different

E. Battaner, E. Florido, J. M. Garcia-Ruiz

We provide a new tool to interpret the large scale structure of the Universe. As suggested in Paper II, energy density filaments could have been produced by subjacent magnetic flux tubes when the Universe was dominated by radiation. In more recent time epochs, small scale filaments have evolved in a complicated way, but large scale filaments have probably su

Manuel A. Bautista, Anil K. Pradhan

The emission spectra and the ionization structure of the low ionization stages of iron, Fe I--IV, in gaseous nebulae are studied. This work includes: (i) new atomic data: photoionization cross sections, total e-ion recombination rates, excitation collision strengths, and transition probabilities; (ii) detailed study of excitation mechanisms for the [Fe II],

M. A. Malkan, F. W. Stecker

Using the excellent observed correlations among various infrared wavebands with 12 and 60 micron luminosities, we calculate the 2-300 micron spectra of galaxies as a function of luminosity. We then use 12 micron and 60 micron galaxy luminosity functions derived from IRAS data, together with recent data on the redshift evolution of galaxy emissivity, to deriv

Koji Mukai

V1432 Aql is currently considered to be an asynchronous AM Her type system, with an orbital period of 12116.3 s and a spin period of 12150 s. I present an alternative model in which V1432 Aql is an intermediate polar with disk overflow or diskless accretion geometry, with a spin period near 4040 s. I argue that published data are insufficient to distinguish

F. De Paolis, Ph. Jetzer, G. Ingrosso

Microlensing results towards the LMC strongly depend on the properties of both the luminous and the dark matter distribution in the Galaxy. The two main sources of uncertainty come from the poor knowledge of the rotation curve at large galactocentric distance and from the possibility that MACHOs follow radial orbits in the outer Galaxy. Given these uncertain

M. A. G. Maia, C. N. A. Willmer, L. N. da Costa

We examine the H1 content of spiral galaxies in groups by using a catalog of loose groups of galaxies identified in a magnitude limited sample m < 15.7 spanning the range 8 h to 18 h in right ascension and +9 to +15 in declination. The redshift completeness of the galaxy sample is ~95%. No significant effect of H1 depletion is found, although there may be a

C. Allende Prieto, B. Ruiz Cobo, R. J. Garcia Lopez

An inversion technique has been developed to recover LTE one-dimensional model photospheres for late-type stars from very high-resolution high signal-to-noise stellar line profiles. It is successfully applied to the Sun using a set of unblended Ti I, Ca I, Cr I and Fe I lines with accurate transition probabilities. Temperature stratification, continuum flux,

C. Allende Prieto, R. J. Garcia Lopez

New improvements in the measurement of both the optical solar spectrum and laboratory wavelengths for lines of neutral iron are combined to extract central wavelength shifts for 1446 lines observed in the Sun. This provides the largest available database of accurate solar wavelengths useful as a reference for comparison with other solar-type stars. It is sho

R. J. Garcia Lopez, M. C. Dominguez Herrera, M. R. Perez de Taoro, C. Casares

Beryllium and oxygen abundances have been derived in a sample of F-type field stars for which lithium abundances had been measured previously, with the aim of obtaining observational constraints to discriminate between the different mixing mechanisms proposed. Mixing associated with the transport of angular momentum in the stellar interior and internal gravi

Abhas Mitra

Depending upon the various models and assumptions, the existing literature on Gamma Ray Bursts (GRBs) mentions that the gross theoretical value of the duration of the burst in the hydrodynamical models is tau~r^2/(eta^2 c), where r is the radius at which the blastwave associated with the fireball (FB) becomes radiative and sufficiently strong. Here eta = E/M

Gian Mario Besana, Sandra Di Rocco

We investigate the projective normality of smooth, linearly normal surfaces of degree 9. All non projectively normal surfaces which are not scrolls over a curve are classified. Results on the projective normality of surface scrolls are also given. One of the reasons that brought us to look at this question is our desire to find examples for a long standing p

Donam Youm

We review various aspects of classical solutions in string theories. Emphasis is placed on their supersymmetry properties, their special roles in string dualities and microscopic interpretations. Topics include black hole solutions in string theories on tori and N=2 supergravity theories; p-branes; microscopic interpretation of black hole entropy. We also re

J. M. Campbell, E. W. N. Glover

We present approximations to tree level multiparton scattering amplitudes which are appropriate when two partons are unresolved. These approximations are required for the analytic isolation of infrared singularities of n+2 parton scattering processes contributing to the next-to-next-to-leading order corrections to n jet cross sections. In each case the colou

UA8 Collaboration, A. Brandt, J. B. Cheze, S. Erhan

We report measurements of the inclusive differential cross section for the single-diffractive reactions: p + pbar --> p + X and p + pbar --> X + pbar at sqrt(s) = 630 GeV, in the momentum transfer range, 0.8 < -t < 2.0 GeV^2 and final state Feynman-x > 0.90. Based on the assumption of factorization, several new features of the Pomeron Flux Factor are determi

M. F. Ertl, M. O. Katanaev, W. Kummer

Among the usual constraints of (1,1) supergravity in d=2 the condition of vanishing bosonic torsion is dropped. Using the inverse supervierbein and the superconnection considerably simplifies the formidable computational problems. It allows to solve the constraints for those fields before taking into account the (identically fulfilled) Bianchi identities. Th

I. L. Drichko, A. M. Diakonov, V. D. Kagan, A. M. Kreshchuk

The parameters of two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure were determined by an acoustical (contactless) method in the delocalized electrons region ($B\le$2.5T). Nonlinear effects in Surface Acoustic Wave (SAW) absorption by 2DEG are determined by the electron heating in the electric field of SAW, which may be described in terms

W. Weinhold, B. Friman, W. Nörenberg

The thermodynamic potential of a system of pions and nucleons is computed including the piN interactions in the P33 channel. A consistent treatment of the width of the resonance in this channel, the Delta(1232) resonance, is explored in detail. In the low-density limit we recover the leading term of the virial expansion for the thermodynamic potential. An in

H. A. Kastrup

Recently is was shown that the imaginary part of the canonical partition function of Schwarzschild black holes with an energy spectrum E_n = σ\sqrt{n} E_P, n= 1,2, ..., has properties which - naively interpreted - leads to the expected unusual thermodynamical properties of such black holes (Hawking temperature, Bekenstein-Hawking entropy etc). The present pa

Ivan G. Avramidi, Giampiero Esposito

The boundary-value problem for Laplace-type operators acting on smooth sections of a vector bundle over a compact Riemannian manifold with generalized local boundary conditions including both normal and tangential derivatives is studied. The condition of strong ellipticity of this boundary-value problem is formulated. The resolvent kernel and the heat kernel

Bertfried Fauser

We propose a geometric method to parameterize inequivalent vacua by dynamical data. Introducing quantum Clifford algebras with arbitrary bilinear forms we distinguish isomorphic algebras --as Clifford algebras-- by different filtrations resp. induced gradings. The idea of a vacuum is introduced as the unique algebraic projection on the base field embedded in

Bo-Qiang Ma, Ivan Schmidt, Jacques Soffer

The quark helicity measured in polarized deep inelastic scattering is different from the quark spin in the rest frame of the nucleon. We point out that the quark spin distributions $Δq_{RF}(x)$ are connected with the quark helicity distributions $Δq(x)$ and the quark transversity distributions $δq(x)$ by an approximate relation: $Δq_{RF}(x) + Δq(x)=2 δq(x)$.

N. M. Bogoliubov, A. G. Izergin, N. A. Kitanine

The correlation functions for a strongly correlated exactly solvable one-dimensional boson system on a finite chain as well as in the thermodynamic limit are calculated explicitly. This system which we call the phase model is the strong coupling limit of the integrable q-boson hopping model. The results are presented as determinants.

H. S. Sharatchandra

Requirements of a conjugate operator are emphasized, especially in its role in uncertainty relations.It is argued that in many contexts it is necessary to extend the Hilbert space in order to define a conjugate operator as in gauge theories. Example of a particle in a box is analysed. This is closely related to the quantum oscillator through cosine states of

David N. Yetter

Braided deformations of (symmetric) monoidal categories are related to Vassiliev theory by a direct generalization of well-known results relating &#34;quantum&#34; knot invariants to Vassiliev invariants. The deformation theory of braidings is subsumed by the deformation theory of monoidal functors, which proves surprisingly rich: the deformation complex of

N. A. Gromov, I. V. Kostyakov, V. V. Kuratov

The extension of FRT quantization theory for the nonsemisimple CK groups is suggested. The quantum orthogonal CK groups are realized as the Hopf algebras of the noncommutative functions over an associative algebras with nilpotent commutative generators. The quantum CK algebras are obtained as the dual objects to the corresponding quantum groups.

Peter Bongaarts, Jacek Brodzki

We study the projective linear group PGL_2(A), associated with an arbitrary algebra A, and its subgroups from the point of view of their action on the space of involutions in A. This action formally resembles Moebius transformations known from complex geometry. By specifying A to be an algebra of bounded operators in a Hilbert space H, we rediscover the Moeb

S. Donev, M. Tashkova

This paper aims to give explicitly all non-linear vacuum solutions to our non-linear field equations, and to define in a coordinate free manner the important subclass of non-linear solutions, which we call almost photon-like. By means of a correct introduction of the local and integral intrinsic angular momentums of these solutions, we saparate the photon-li

D. Babusci, G. Giordano, G. Matone

The Baldin sum rule for the nucleon has been recalculated at the light of the most recent photoabsorption cross section measurements. The proton value (alpha + beta)_p =13.69 +/- 0.14 is smaller but consistent with the one usually quoted in literature. However, the value for the neutron (alpha + β)_n =14.40 +/- 0.66 turns out to be three standard deviations

A. Leviatan, R. Bijker

We present an analysis of electromagnetic elastic form factors, helicity amplitudes and strong decay widths of non-strange baryon resonances, within a collective model of the nucleon. Flavor-breaking and stretching effects are considered. Deviations from the naive three-constituents description are pointed out.

R. Caracciolo, A. De Pace, H. Feshbach, A. Molinari

We develop a statistical theory of the mean field. It is based on the proposition that the mean field can be obtained as an energy average. Moreover, it is assumed that the matrix elements of the residual interaction are random with the average value of zero. Explicit expressions for the mean field and the fluctuation away from the average are obtained. The

Ionuţ Ciocan-Fontanine

The main goal of this paper is to give a unified description for the structure of the small quantum cohomology rings for all homogeneous spaces of SL_n(C).

Yeuk-Kwan E. Cheung, Ori J. Ganor, Morten Krogh

We study the two-point correlators of the currents of the $E_8$ global symmetry in the $N=(1,0)$ superconformal six-dimensional theory as well as in the 4D superconformal theories upon toroidal compactification. From the high-energy behavior of the correlator we deduce that in 4D 10 copies of the superconformal theory with $E_8$ global symmetry can be couple

Khalil M. Bitar, Urs M. Heller, Rajamani Narayanan

Parity and flavor symmetry is not broken in QCD. Using this fact, we propose a new method to measure the chiral condensate in lattice QCD using Wilson fermions with an operator that breaks parity and flavor in addition to the chiral symmetry.

S. Falkenberg, B. Geyer, P. Lavrov, P. Moshin

We consider generating functionals of Green&#39;s functions with external fields in the framework of BV and BLT quantization schemes for general gauge theories. The corresponding Ward identities are obtained, and the gauge dependence is studied.

Faheem Hussain, Roberto Iengo, Carmen Nunez, Claudio A. Scrucca

We compute the amplitude for the radiation of massless NS-NS closed string states from the interaction of two moving D-branes. We consider particle-like D-branes with reference to 4-dimensional spacetime, in toroidal and orbifold compactifications, and we work out the relevant world sheet propagators within the moving boundary state formalism. We find no on-

Dimitry Leites, Xuan Peiqi

In 70&#39;s A.A. Kirillov interpreted the stationary Schroedinger (Sturm-Liouville) operator as an element of the dual space to the Virasoro algebra, i.e., the nontrivial central extension of the Witt algebra. He interpreted the KdV operator in terms of the stabilizer of the Schroedinger operator. By studying the coadjoint representation of the simplest nont

S. Jaimungal, L. D. Paniak

The effect of topology on the thermodynamics of a gas of adjoint representation charges interacting via 1+1 dimensional SU(N) gauge fields is investigated. We demonstrate explicitly the existence of multiple vacua parameterized by the discrete superselection variable k=1,...,N. In the low pressure limit, the k dependence of the adjoint gas equation of state

C. Adam

Using mass perturbation theory, we infer the bound-state spectrum of massive QED$_2$ and compute some decay widths of unstable bound states. Further, we discuss scattering processes, where all the resonances and particle production thresholds are properly taken into account by our methods.

C. Adam

We derive all covariant and consistent divergence and commutator anomalies of chiral QED$_2$ within the framework of canonical quantization of the fermions. Further, we compute the time evolution of all occurring operators and find that all commutators evolve canonically. We comment on the relation of our results to the finding of a nontrivial U(1)-curvature

Evangelos Mavrikis

The present paper deals with N=1 2D supersymmetric integrable quantum field theory. The S-matrix proposed to describe the interactions between supersymmetric particles is applied to theories involving topological excitations of zero central charge. Bound states can fit consistently within this type of theories, since the bootstrap can be shown to close. The

R. Akhoury, V. I. Zakharov

We review the physics of the ultraviolet renormalon. This mini-review is intended to be a sequel to the review by the same authors at the &#34;QCD &#39;96&#34; conference last year (hep-ph/9610492).

F. Hautmann

The scattering of two off-shell photons is an infrared-safe process in QCD. For photon virtualities in the range of a few GeV, accessible at LEPII, power-behaved contributions to the total cross section may become non-negligible. Based on a dispersion relation for the running coupling, we discuss these contributions and calculate the coefficients of the lead

G. Anderson, U. Baur, M. Berger, F. Borcherding

One of the options for an accelerator beyond the LHC is a hadron collider with higher energy. Work is going on to explore accelerator technologies that would make such a machine feasible. This workshop concentrated on the physics and detector issues associated with a hadron collider with an energy in the center of mass of the order of 100 to 200 TeV.

R. Kirschner

The small $x$ behaviour of polarized parton distributions is related to non-leading reggeons in the framework of the high-energy effective action. Double-logarithmic contributions to the reggeon interaction beyond the ones included in the GLAP equation are encountered in all polarized parton distributions. The transversity distributions of quarks and gluons

G. Parente, A. V. Kotikov

We present very simple non-integral relations between deep inelastic structure functions $F_L$, $F_2$ and the gluon distribution at small $x$ based on perturbative QCD which are useful for the phenomenological analysis of data at low $x$. As an application we extract the deep inelastic scattering cross-sections ratio $R= σ_L/σ_T$ in the range $10^{-4} \leq x

S. M. Bilenky

A general overview of neutrino physics is given. The history of the neutrino starting from Pauli and Fermi is briefly presented. Two-component neutrinos, the phenomenological V-A theory and the standard model are discussed. The problem of neutrino masses and mixing is reviewed.

S. Filipponi, G. Pancheri, Y. Srivastava

Based on available data for mesonic resonances of light, medium and heavy flavors, we have performed a global analysis to construct the corresponding linear Regge trajectories. These have been supplemented by results from various phenomenological models presented in the literature. A satisfactory formula is found for the dependence of the intercept and the s

Chris Michael

Topics covered in this review are the lattice gauge theory approach to the evaluation of non-perturbative hadronic interactions from first principles, particularly applications to glueballs, inter-quark potentials, the running coupling constant and hybrid mesons. Also discussed are the limitations of the quenched approximation.

Petteri Keränen

We propose a test for non-standard neutrino-neutrino interactions by using ultrahigh energy AGN neutrinos. Such interactions would influence the AGN neutrino flux due to collisions with cosmic background neutrinos. For typical AGN neutrinos we obtain an upper limit for the coupling constant $g<6.4\cdot 10^{-3}$ if the mediator is light and $g/(M_X/MeV) <0.01