April 1995 arXiv papers — page 8

J. Barcelos-Neto, N. R. F. Braga, S. M. de Souza

The field-antifield quantization method is used to calculate the trace anomaly for a massless scalar field in a curved background, by means of the zeta function regularization procedure.

Paul A. Blaga, L. Tataru, Ion V. Vancea

The BRST cohomology group in the space of local functionals of the fields for the two-dimensional conformally invariant gravity is calculated. All classical local actions (ghost number equal to zero) and all candidate anomalies are given and discussed for our model.

L. Tataru, Ion V. Vancea

We study the BRST cohomology within a local conformal Lagrangian field theory model built on a two dimensional Riemann surface with no boundary. We deal with the case of the complex structure parametrized by Beltrami differential and the scalar matter fields. The computation of {\em all} elements of the BRST cohomology is given.

S. M. Sergeev, V. V. Mangazeev, Yu. G. Stroganov

In this paper we formulate an integrable model on the simple cubic lattice. The $N$ -- valued spin variables of the model belong to edges of the lattice. The Boltzmann weights of the model obey the vertex type Tetrahedron Equation. In the thermodynamic limit our model is equivalent to the Bazhanov -- Baxter Model. In the case when $N=2$ we reproduce the Kore

D. Chakraverty, T. De, B. Dutta-Roy, A. Kundu

Supersymmetric hadrons of the type $\tg\tg$, $\tg g$ and $\tg q\bar q$ could exist depending on the masses of the gluino and the squarks being in an appropriate range of values. We find the energy levels of $\tg g$ and $\tg q\bar q$ bound states (where $q$ denotes a light quark, $u$, $d$ or $s$), as well as the strong interaction transition rates among them,

Marc Sher

Some extensions of the standard model contain additional leptons which are vectorlike under weak isospin. A class of models is considered in which these leptons do not appreciably mix with the known leptons. In such models, the heavy charged lepton and the heavy neutrino are degenerate in mass, and the degeneracy is broken by radiative corrections. The mass

G. Alexanian, V. P. Nair

We discuss how magnetic screening can be systematically included in a self-consistent way for Chromodynamics at high temperatures. The resulting gap equation, which gives the summation of self-energy iterations, is calculated to one-loop order and leads to a nonzero value for the magnetic mass.

Michael Krämer

Inelastic photoproduction of $J/ψ$ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. The QCD radiative corrections to the color-singlet model of this reaction have recently been calculated. They are large at moderate photon energies, but decrease with increasing energies. I compare the cross section and th

Kim Maltman

The existence of isospin admixtures in the physical $Λ$, $π^o$ complicates the extraction of Delta I=3/2 non-leptonic hyperon decay amplitudes from experimental data, allowing contributions associated with large Delta I=1/2 amplitudes to appear in the (nominally) Delta I=3/2 amplitudes obtained ignoring these admixtures. We show how to correct for this effec

Kim Maltman

The forms of the neutral, non-strange pseudoscalar propagator matrix and mixed axial current correlator, $\lngle0|T(A_μ^3 A_ν^8)|0\rangle$, are discussed at next-to-leading (one-loop) order in chiral perturbation theory, and the results compared to those obtained using QCD sum rules. This comparison provides a check of the truncations employed in the sum rul

T. Yamanishi, T. Morii, S. Tanaka

Hadroproductions of charmonium and bottomonium $χ_J$ in polarized $pp$ collisions at RHIC energies are studied. Two--spin asymmetries $A_{LL}^{χ_J}(pp)$ for these reactions are very good parameters for examining the polarized gluon distributions in a proton.

R. L. Altmeyer, M. Gockeler, R. Horsley, E. Laermann

We calculate the hadronic coupling constants $g_{NNπ}$ and $g_{ρππ}$ in QCD, including dynamical quarks in the framework of staggered fermions in the lattice approach. For the nucleon--pion coupling we obtain $g_{NNπ} = 13.8 \pm 5.8$, to be compared with the experimental value $13.13 \pm 0.07$. The $ρππ$ coupling has been analysed for two different sets of o

Jose W. Maluf

In the framework of the teleparallel equivalent of general relativity the energy density of asymptoticaly flat gravitational fields can be naturally and unambiguously defined. Upon integration of the energy density over the whole three dimensional space we obtain the ADM energy. We use this energy density to calculate the energy inside a Schwarzschild black

J. Bellissard

Let $H(ε, x)$ be a finite dimensional hermitian matrix depending on the variable $x$ taking its values on a 2D manifold and changing with $ε$. If at $ε=0$ two bands are touching, we give a formula for the change of Chern number of these bands as $ε$ passes through zero.

B. Bassetti, G. Mazzoletti, P. Jona

A new model for lamellar surfaces formed by anisotropic molecules is proposed. The molecules have internal degrees of freedom, associated with their flexible section of length $N$ at zero temperature. We obtain a 2D non-standard six vertex model, which is exactly soluble and exhibits a finite order transition. The order and the character of the transition ar

Klaus Frahm

The exact solution of the Dorokhov-Mello-Pereyra-Kumar-equation for quasi one-dimensional disordered conductors in the unitary symmetry class is employed to calculate all $m$-point correlation functions by a generalization of the method of orthogonal polynomials. We obtain closed expressions for the first two conductance moments which are valid for the whole

M. Casas, F. Dalfovo, A. Lastri, Ll. Serra

A novel density functional, which accounts correctly for the equation of state, the static response function and the phonon-roton dispersion in bulk liquid helium, is used to predict static and dynamic properties of helium droplets. The static density profile is found to exhibit significant oscillations, which are accompanied by deviations of the evaporation

Stefano Lepri, Antonio Politi, Alessandro Torcini

Instabilities in 1D spatially extended systems are studied with the aid of both temporal and spatial Lyapunov exponents. A suitable representation of the spectra allows a compact description of all the possible disturbances in tangent space. The analysis is carried out for chaotic and periodic spatiotemporal patterns. Singularities of the spectra and localiz

Craig J. Copi, David N. Schramm

The \HOmega\ diagram is resurrected to dramatically illustrate the nature of the key problems in physical cosmology today and the role that nuclear physics plays in many of them. In particular it is noted that the constraints on \OmegaB\ from big bang nucleosynthesis do not overlap with the constraints on \OmegaVis\ nor have significant overlap with the lowe

O. R. Pols, C. A. Tout, P. P. Eggleton, Z. Han

We present a simple and efficient, yet reasonably accurate, equation of state, which at the moderately low temperatures and high densities found in the interiors of stars less massive than the Sun is substantially more accurate than its predecessor by Eggleton, Faulkner & Flannery. Along with the most recently available values in tabular form of opacities, n

Michele D. Thornley, Christine D. Wilson

We present a fully sampled map of the inner 3.2 kpc of the nearby spiral galaxy NGC 2403 in the CO J=1-0 line. These data emphasize the relatively small contribution of molecular hydrogen to the cold gas content of this galaxy, and confirm that the gas surface densities in the inner 2.8 kpc of NGC 2403 lie below the critical surface density for star formatio

L. S. Nazarova

The results of calculations of gas emission spectra with both central and extended sources of ionization have been compared to the ratio of line intensities observed in the extended narrow line region of NGC1068. The origin of an extended structure of anomalous strength in the $[OIII] λ5007$ and $[NeV] λ3425$ lines found by Evans & Dopita (1986) and Bergeron

PHILIP D. MANNHEIM

In a previous paper we presented a typical set of galactic rotation curves associated with the linear gravitational potential of the conformal invariant fourth order theory of gravity which has recently been advanced by Mannheim and Kazanas as a candidate alternative to the standard second order Newton-Einstein theory. Reasonable agreement with data was obta

R. Carballo, X. Barcons, J. K. Webb

We present the first moderate resolution (approx. 40--120 km/s) spectroscopic observations of the bright (V<16.7) high-redshift QSOs Q1107+487 (z_{em} = 2.965) and Q1442+295 (z_{em} = 2.669) (Sanduleak & Pesch 1989). The relatively high signal to noise reached in the spectra along with an extensive wavelength coverage of the Lyman alpha and the Lyman beta fo

Brigita Kutjnak-Urbanc, Stefano Zapperi, Sava Milošević, H. Eugene Stanley

We investigate the sandpile model on the two--dimensional Sierpinski gasket fractal. We find that the model displays novel critical behavior, and we analyze the distribution functions of avalanche sizes, lifetimes and topplings and calculate the associated critical exponents $τ= 1.51 \pm 0.04$, $α= 1.63 \pm 0.04$ and $μ= 1.36 \pm 0.04$. The avalanche size di

J. W. Moffat

Regularity theorems are presented for cosmology and gravitational collapse in non-Riemannian gravitational theories. These theorems establish conditions necessary to allow the existence of timelike and null path complete spacetimes for matter that satisfies the positive energy condition. Non-Riemannian theories of gravity can have solutions that have a non-s

S. P. de Alwis, N. Ohta

We discuss the relation between the micro-canonical and the canonical ensemble for black holes, and highlight some problems associated with extreme black holes already at the classical level. Then we discuss the contribution of quantum fields and demonstrate that the partition functions for scalar and Dirac (Majorana) fields in static space-time backgrounds,

J. J Gomez-Cadenas, M. C. Gonzalez-Garcia

Our goal in this paper is to examine the discovery potential of laboratory experiments searching for the oscillation $ν_μ(ν_e) \rightarrow ν_τ$, in the light of recent data on solar and atmospheric neutrino experiments, which we analyse together with the most restrictive results from laboratory experiments on neutrino oscillations. In order to explain simult

Gerhard A. Schuler

Uncertainties in the next-to-leading-order calculations of heavy-quark ($Q$) production are investigated. Predictions for total cross sections, single-inclusive distributions of heavy quarks and heavy flavoured hadrons, as well as for $Q\bar{Q}$ correlations, are compared with charm and bottom data. The description of heavy-quarkonium production requires a s

A. Dedes, A. B. Lahanas, K. Tamvakis

We study Radiative Electroweak Symmetry Breaking in the Minimal Supersymmetric Standard Model (MSSM). We employ the 2-loop Renormalization Group equations for running masses and couplings taking into account sparticle threshold effects. The decoupling of each particle below its threshold is realized by a step function in all one-loop Renormalization Group eq

H. Kleinert

The path integral of the relativistic Coulomb system is solved, and the wave functions are extracted from the resulting amplitude.

Carlos Castro

An exact quantization of the spherical membrane moving in flat target spacetime backgrounds is performed. Crucial ingredients are the exact integrabilty of the $3D~SU(\infty)$ continuous Toda equation and the quasi-finite highest weight irreducible representations of $W_{\infty}$ algebras. Both continuous and discrete energy levels are found. The latter are

Ph. Blanchard, A. Jadczyk

We review what we call &#34;event-enhanced formalism&#34; of quantum theory. In this approach we explicitly assume classical nature of events. Given a quantum system, that is coupled to a classical one by a suitable coupling, classical events are being triggered. The trigerring process is partly random and partly deterministic. Within this new approach one c

Chong-Sun Chu, Pei-Ming Ho, Bruno Zumino

We describe the quantum sphere of Podleś for $c=0$ by means of a stereographic projection which is analogous to that which exhibits the classical sphere as a complex manifold. We show that the algebra of functions and the differential calculus on the sphere are covariant under the coaction of fractional transformations with \SU coefficients as well as under

R. Rosenfelder, A. W. Schreiber

For the scalar Wick-Cutkosky model in the particle representation we perform a similar variational calculation for the 2-point function as was done by Feynman for the polaron problem. We employ a quadratic nonlocal trial action with a retardation function for which several ansätze are used. The variational parameters are determined by minimizing the variatio

Kang Seog Lee

We present a simple model for the dimuon production from the decay of vector mesons which are hadronized from a baryon-free quark-gluon plasma. Continuous decay of vector mesons in the medium is known to enhance the dimuon production and in our model we can estimate the total yield of dimuons decayed from vector mesons through the rate equations for the numb

Andrea Brignole, Ferruccio Feruglio, Fabio Zwirner

We construct $N=1$ supergravity models where the gauge symmetry and supersymmetry are both spontaneously broken, with naturally vanishing classical vacuum energy and unsuppressed Goldstino components along gauge non-singlet directions. We discuss some physically interesting situations where such a mechanism could play a role, and identify the breaking of a g

P. Kanti, K. Tamvakis

We extend existing treatments of black hole solutions in String Gravity to include moduli fields. We compute the external moduli and dilaton hair, as well as of their associated axions,to $O(α&#39;)$ in the framework of the loop corrected superstring effective action for a Kerr-Newman black hole background.

J. C. Brunelli, Ashok Das

We obtain the conserved, nonlocal charges for the supersymmetric two boson hierarchy from fractional powers of its Lax operator. We show that these charges reduce to the ones of the supersymmetric KdV system under appropriate reduction. We study the algebra of the nonlocal, local and supersymmetry charges with respect to the first and the second Hamiltonian

Thomas P. Branson, Peter B. Gilkey, Dmitri V. Vassilevich

We study the fifth term in the asymptotic expansion of the heat operator trace for a partial differential operator of Laplace type on a compact Riemannian manifold with Dirichlet or Neumann boundary conditions.

A. G. Mirzabekian, G. A. Vilkovisky

We present the solution of the problem of the $1/\Box, \Box \to 0,$ asymptotic terms discovered in the one-loop form factors of the gravitational effective action. Owing to certain constraints among their coefficients, which we establish, these terms cancel in the vacuum stress tensor and do not violate the asymptotic flatness of the expectation value of the

Ashoke Sen

It has recently been conjectured that the type IIA string theory compactified on K3 and the heterotic string theory compactified on a four dimensional torus describe identical string theories. The fundamental heterotic string can be regarded as a non-singular soliton solution of the type IIA string theory with a semi-infinite throat. We show that this soluti

Motoi Tachibana

Motivated by the work of Kalloniatis, Pauli and Pinsky, we consider the theory of light-cone quantized $QCD_{1+1}$ on a spatial circle with periodic and anti-periodic boundary conditions on the gluon and quark fields respectively. This approach is based on Discretized Light-Cone Quantization (DLCQ). We investigate the canonical structures of the theory. We s

S. James Gates,, Lubna Rana

An explicit construction of theories of spinning particles, both massive and massless, is given with arbitrary extended supersymmetry on the world-line. As an application of our results, we give a universal description of 3D (and via truncation all lower dimensional) supersymmetric scalar multiplets with arbitrary N-extended supersymmetry.

Sergey N. Solodukhin

The quantum entanglement entropy of an eternal black hole is studied. We argue that the relevant Euclidean path integral is taken over fields defined on $α$-fold covering of the black hole instanton. The statement that divergences of the entropy are renormalized by renormalization of gravitational couplings in the effective action is proved for non-minimally

G. E. Brown, Mannque Rho

Chiral restoration phase transition in hot and/or dense hadronic matter is discussed in terms of the BR scaling based on chiral symmetry and scale anomaly of QCD. The precise connection between the scalar field that figures in the trace anomaly and the sigma field that figures in the linear $σ$ model is established. It is suggested that in hot and/or dense m

Andreas S. Kronfeld

Most of the poorly known parameters of the Standard Model cannot be determined without reliable calculations in nonperturbative QCD. Lattice gauge theory provides a first-principles definition of the required functional integrals, and hence offers ways of performing these calculations. This paper reviews the progress in computing hadron spectra and electrowe

R. Akhoury, V. I. Zakharov

We discuss $1/Q$ corrections to hard processes in QCD where $Q$ is a large mass parameter like the total energy in $e^+e^-$ annihilation. The main problem we address ourselves to is whether these corrections to different processes (concentrating for definiteness on the Thrust and the Drell-Yan cross section) can be related to each other in a reliable way so

J. Kwiecinski, A. D. Martin

Hard scattering processes involving hadrons at small $x$ are described by a $k_T$-factorization formula driven by a BFKL gluon. We explore the equivalence of this description to a collinear-factorization approach in which the anomalous dimensions $γ_{gg}$ and $γ_{qg}/α_S$ are expressed as power series in $α_S \log (1/x)$, or to be precise $α_S/ω$ where $ω$ i

Wilfried Buchmuller

We pursue the hypothesis that the events with a large rapidity gap, observed at HERA, reflect the scattering of electrons off lumps of wee partons inside the proton. A simple scaling behaviour is predicted for the diffractive structure functions, which are related to the inclusive structure function $F_2(x,Q^2)$ at small values of the scaling variable $x$. T

H. Heiselberg, X. N. Wang

The thermalization process is studied in an expanding parton gas using the Boltzmann equation with two types of collision terms. In the relaxation time approximation we determine the criteria under which a time-dependent relaxation time leads to thermalization of the partons. We calculate the entropy production due to collisions for the general time-dependen

R. Peschanski, C. A. Savoy

Gaugino condensation in the hidden sector of supergravity models is described within a Nambu-Jona-Lasinio type of approach by minimization of a one-loop scalar potential. The essential ingredients of the mechanism are auxiliary superfields whose v.e.v. generate gaugino condensation and supersymmetry breaking, introduced through Lagrange multipliers. For phen

J. R. Espinosa, M. Quiros

Depending on the Higgs-boson and top-quark masses, $M_H$ and $M_t$, the effective potential of the Standard Model at finite (and zero) temperature can have a deep and unphysical stable minimum $\langle ϕ(T)\rangle$ at values of the field much larger than $G_F^{-1/2}$. We have computed absolute lower bounds on $M_H$, as a function of $M_t$, imposing the condi

A. B. Lahanas

I discuss the static quantities of the W boson, magnetic dipole and electric quadrupole moments, in the context of the minimal supersymmetric standard model, in which supersymmetry is broken by soft terms $A_o,\, m_o,\, M_{1/2}$. Following a renormalization group analysis it is found that the supersymmetric values of $Δk_γ$ and $ΔQ_γ$ can be largely differen

Res Urech

In order to calculate the rho - omega mixing we extend the chiral couplings of the low-lying vector mesons in chiral perturbation theory to a lagrangian that contains two vector fields. We determine the momentum dependence of the two-point function and recover an earlier result for the on-shell expression. We discuss the off-shell behaviour of the mixing.

Kim Maltman

The mixed-isospin vector current correlator, $\langle 0\vert T(V^ρ_μV^ω_ν)\vert 0\rangle$ is evaluated using both QCD sum rules and Chiral Perturbation Theory (ChPT) to one-loop order. The sum rule treatment is a modification of previous analyses necessitated by the observation that those analyses produce forms of the correlator that fail to be dominated, ne

C. Glenn Boyd, Benjamin Grinstein, Richard F. Lebed

We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function to B->D* l νform factors, and extract |V_{cb}|=0.037^{+0.003}_{-0.002} from experimental data with a least squares fit. O

Howard Baer, Chih-Hao Chen, Chung Kao, Xerxes Tata

We examine the capability of a $\sqrt{s}=2$ TeV Tevatron $p\bar p$ collider to discover supersymmetry, given a luminosity upgrade to amass $25\ fb^{-1}$ of data. We compare with the corresponding reach of the Tevatron Main Injector ($1\ fb^{-1}$ of data). Working within the framework of minimal supergravity with gauge coupling unification and radiative elect

B. L. Altshuler, L. B. Ioffe, A. J. Millis

We study $T=0$ spin density wave transitions in two dimensional Fermi liquids in which the ordering wavevector $\bf Q$ is such that the tangents to the Fermi line at the points connected by $\bf Q$ are parallel (e.g. $Q=2p_F$ in a system with a circular Fermi line) and the Fermi line is not flat. We show that the transition is first order if the ordering wav

E. Pitard, M. L. Rosinberg, G. Stell, G. Tarjus

Using a liquid-state approach based on Ornstein-Zernike equations, we study the behavior of a fluid inside a porous disordered matrix near the liquid-gas critical point.The results obtained within various standard approximation schemes such as lowest-order $γ$-ordering and the mean-spherical approximation suggest that the critical behavior is closely related

C. S. Frenk, A. E. Evrard, S. D. M. White, FJ Summers

We use high resolution simulations to study the formation and distribution of galaxies within a cluster which forms hierarchically. We follow both dark matter and baryonic gas which is subject to thermal pressure, shocks and radiative cooling. Galaxy formation is identified with the dissipative collapse of the gas into cold, compact knots. We examine two ext

H. Ardavan

In a recent paper, Li and Melrose have claimed that the splitting - due to relativistic effects - of the Alfven surface in an axisymmetric pulsar wind does not occur. Here we refute this claim by showing that, unless the solution that describes the flow along each open magnetic field line passes through the pure Alfvenic point (which is one of the manifestat

G. F. Lewis, M. J. Irwin

The passage of stars through the beam of a lensed quasar can induce violent fluctuations in its apparent brightness. The fluctuations observed in the Huchra lens, (2237+0305), are taken to be the first evidence of this ``microlensing&#39;&#39; occurring in lensing systems. Subsequent microlensing events observed in this system and in other gravitational lens

A. Fernandez-Soto, X. Barcons, R. Carballo, J. K. Webb

We present the results of our study on three close pairs of QSOs. Our results are consistent with the existence of a proximity effect due to the foreground QSO, but due to its weakness we can only reject the absence of such effect at approx. 1 sigma level. By modelling this proximity effect in terms of a simple photoionisation model, we find the best value f

E. BRANCHINI, M. PLIONIS

Starting from the observed redshift distribution of a volume limited Abell/ACO cluster sample we use a 2-step procedure to recover their distances and peculiar velocities (assuming linear theory and linear biasing). The resulting 3D dipole is found to be 23\% less than the corresponding z-space one which leads to a value of $β\approx 0.21$ consistent with an

Tomonori Totani, Katsuhiko Sato

It is greatly expected that the relic neutrino background from past supernovae is detected by Superkamiokande (SK) which is now under construction. We calculate the spectrum and the event rate at SK systematically by using the results of simulations of a supernova explosion and reasonable supernova rates. We also investigate the effect of a cosmological cons

Carel Faber

We determine necessary conditions for ample divisors in arbitrary genus as well as for very ample divisors in genus 2 and 3. We also compute the intersection numbers $λ^9$ and $λ_{g-1}^3$ in genus 4. The latter number is relevant for counting curves of higher genus on manifolds, cf. the recent work of Bershadsky et al.

R. Pandharipande

The theory of Q-Cartier divisors on the space of n-pointed, genus 0, stable maps to projective space is considered. Generators and Picard numbers are computed. A recursive algorithm computing all top intersection products of Q-Divisors is established. As a corollary, an algorithm computing all characteristic numbers of rational curves in P^r is proven (inclu

J. Harris, R. Pandharipande

In this short note, a new computation of the degree of the locus of 3-nodal plane curves in the linear system of degree d plane curves is given. The answer is expressed as a tautological class on a blow-up of the Hilbert scheme of 3 points in the plane. The class is evaluated by the Bott residue formula.

Rajesh R. Parwani

A recent result of Gusynin, Miransky and Shovkovy concerning chiral symmetry breaking by a constant external magnetic field in parity-invariant three-dimensional QED is generalised to the case of inhomogeneous fields by relating the phenomenon to the zero modes of the Dirac equation. Virtual photon radiative corrections and four-dimensional QED are briefly d

S. W. Hawking, S. F. Ross

A number of attempts have recently been made to extend the conjectured $S$ duality of Yang Mills theory to gravity. Central to these speculations has been the belief that electrically and magnetically charged black holes, the solitons of quantum gravity, have identical quantum properties. This is not obvious, because although duality is a symmetry of the cla

D. Belitz, T. R. Kirkpatrick

An effective field theory is derived for the ferromagnetic transition of diffusive electrons at T=0. The static disorder which leads to diffusive electron dynamics induces an effective long-range interaction between the spins of the form 1/r^(2d-2). This leads to unusual scaling behavior at the quantum critical point, which is determined exactly. The crossov

Zhu-Pei Shi, Rajiv R. P. Singh, Martin P. Gelfand, Ziqiang Wang

We present an application of high-order series expansion in the coupling constants for the ground state properties of correlated lattice fermion systems. Expansions have been generated up to order $(t/J)^{14}$ for $d=1$ and $(t/J)^8$ for $d=2,\ 3$ for certain properties of the symmetric Kondo lattice model. Analyzing the susceptibility series, we find eviden

J. D. Kim

We study boundary reflection matrix for the quantum field theory defined on a half line using Feynman&#39;s perturbation theory. The boundary reflection matrix can be extracted directly from the two-point correlation function. This enables us to determine the boundary reflection matrix for affine Toda field theory with the Neumann boundary condition modulo `

C. A. Hayward, D. Poilblanc, R. M. Noack, D. J. Scalapino

Applying three independent techniques, we give numerical evidence for a finite superfluid density in isotropic hole-doped t--J ladders: We show the existence of anomalous flux quantization, emphasising the contrasting behaviour to that found in the `Luttinger liquid' regime stabilised at low electron densities; We consider the nature of the low-lying excitat

Laurent Baulieu

We display properties of the general formalism which associates to any given gauge symmetry a topological action and a system of topological BRST and anti-BRST equations. We emphasize the distinction between the antighosts of the geometrical BRST equations and the antighosts occuring in field theory. We propose a transmutation mechanism between these objects

Felix von Oppen, Tilo Wettig, Jochen Müller

The localization length $ξ_2$ for coherent propagation of two interacting particles in a random potential is studied using a novel and efficient numerical method. We find that the enhancement of $ξ_2$ over the one-particle localization length $ξ_1$ satisfies the scaling relation $ξ_2/ξ_1=f(u/Δ_ξ)$, where $u$ is the interaction strength and $Δ_ξ$ the level sp

Hisakazu Minakata

We derive the constraints imposed on neutrino masses and mixing angles by performing a combined analysis of the data from the Los Alamos and the other terrestrial neutrino oscillation experiments with the assumption of the flavor-mixing solutions to the solar neutrino problem. In a three-flavor mixing scheme which ignores the possibility of sterile neutrinos

S. A. APIKYAN, C. J. EFTHIMIOU

We propose a new massive integrable model in quantum field theory. This model is obtained as a perturbed model of the minimal conformal field theories on the hyper-elliptic surfaces by a particular relavant operator $V_{(1,1)}^{(t)}$. The non-local conserved charges of the model and their $q$-deformed algebra are also constructed explicitly.

J. Donin, L. Makar-Limanov

Poisson brackets (P.b) are the natural initial terms for the deformation quantization of commutative algebras. There is an open problem whether any Poisson bracket on the polynomial algebra of $n$ variables can be quantized. It is known (Poincare-Birkhoff-Witt theorem) that any linear P.b. for all $n$ can be quantized. On the other hand, it is easy to show t

V. Topor Pop, M. Gyulassy, X. N. Wang, A. Andrighetto

The systematics of strangeness enhancement is calculated using the HIJING and VENUS models and compared to recent data on $\,pp\,$, $\,pA\,$ and $\,AA\,$ collisions at CERN/SPS energies ($200A\,\, GeV\,$). The HIJING model is used to perform a {\em linear} extrapolation from $pp$ to $AA$. VENUS is used to estimate the effects of final state cascading and pos

R. Rosenfelder, A. W. Schreiber

We apply nonperturbative variational techniques to a relativistic scalar field theory in which heavy bosons (``nucleons&#39;&#39;) interact with light scalar mesons via a Yukawa coupling. Integrating out the meson field and neglecting the nucleon vacuum polarization one obtains an effective action in terms of the heavy particle coordinates which is nonlocal

D. V. Fedorov, E. Garrido, A. S. Jensen

We investigate effects of finite core-spin in two-neutron halos in the three-body model consisting of two neutrons and a core. The states in the neutron-core subsystem can then have an additional splitting due to the coupling of the neutron and core spins. The connection between the structure of the total system and the states of the neutron-core subsystem d

Youngjai Kiem, Dahl Park

General static solutions for a massless scalar field coupled to a class of effectively 2-d gravity theories continuously connecting spherically symmetric $d$-dimensional Einstein gravity ($d >3$) and the CGHS model are analytically obtained. They include black holes and point scalar charge solutions with naked singularities, and are used to give an analytic

Teruhiko Kawano

We consider two-dimensional quantum gravity coupled to matter in the temporal gauge, using the Polyakov path integral. We show that the integration over the metric can be explicitly performed under some plausible assumptions. We also discuss that the critical dimensions in string theory may not be determined in the temporal gauge.

Cornelius Sochichiu

Canonical quantization of anomalous SU(N) Yang-Mills models is considered. It is shown that the gauge invariance of the quantum theory can be saved in spite of degeneracy of the Wess-Zumino action.

E. Elizalde, C. O. Lousto, S. D. Odintsov, A. Romeo

The running coupling constants (in particular, the gravitational one) are studied in asymptotically free GUTs and in finite GUTs in curved spacetime, with explicit examples. The running gravitational coupling is used to calculate the leading quantum GUT corrections to the Newtonian potential, which turn out to be of logarithmic form in asymptotically free GU

Q. J. Liu, W. Q. Chao, G. Wilk

We present a Monte-Carlo simulation of energy deposition process in relativistic heavy-ion collisions based on a new realization of the Interacting-Gluon-Model (IGM) for high energy $N-N$ collisions. In particular we show results for proton spectra from collisions of $E_{lab}=200 \ GeV/N$ $^{32}$S beam incident on $^{32}$S target and analyze the energy and m

A. M. Gavrilik, I. I. Kachurik, A. V. Tertychnyj

With quantum groups $U_q(su_n)$ taken as classifying symmetries for hadrons of $n$ flavors, we calculate within irreducible representation $D^+_{12}(p-1,p-3,p-4;p,p-2)$ ($p \in {\bf Z}$) of &#39;dynamical&#39; quantum group $U_q(u_{4,1})$ the masses of baryons ${1\over 2}^+$ that belong to ${\it 20}$-plet of $U_q(su_4)$. The obtained $q$-analog of mass relat

M. J. Gibbs, B. R. Webber

We describe a Monte Carlo event generator for the simulation of baryon- and lepton-number violating processes at supercolliders. The package, {\HERBVI}, is designed as a hard-process generator interfacing to the general hadronic event simulation program {\HW}. In view of the very high multiplicity of gauge bosons expected in such processes, particular attent

K. C. Bowler

We present a study of semi-leptonic $\bar B\tp D\ell\barν$ decays in quenched lattice QCD through a calculation of the matrix element $\la D|\bar cγ_μb|\bar B\ra$ on a $24^3\times 48$ lattice at $β=6.2$, using an $\ord{a}$-improved fermion action. We perform the calculation for several values of the initial and final heavy-quark masses around the charm mass,

K. Golec-Biernat, J. Kwiecinski

The QCD analysis of deep inelastic diffractive scattering is performed assuming the dominance of the &#34;soft&#34; pomeron exchange and simple, physically motivated parametrization of parton distributions in a pomeron. Results of the analysis are compared with the recent data obtained by the H1 collaboration at HERA. Both the LO and NLO approximations are c

N. Brambilla, E. Montaldi, G. M. Prosperi

We extend to regular QCD the derivation of a confining $ q \bar{q}$ Bethe--Salpeter equation previously given for the simplest model of scalar QCD in which quarks are treated as spinless particles. We start from the same assumptions on the Wilson loop integral already adopted in the derivation of a semirelativistic heavy quark potential. We show that, by sta

P. Zenczykowski

Contributions of low energy &#34;eye&#34; and &#34;figure-eight&#34; quark diagrams to the $K \rightarrow π$ weak transitions are studied in a hadron- level phenomenological approach. It is shown that these contributions may be estimated by considering meson-cloud effects. If all intermediate mesons under consideration are degenerate only the &#34;eye&#34; (

Isamu Watanabe

We present the efficient technique to extract the signal of the intermediate mass Higgs boson from the backgrounds at future $γγ$ colliders. For a clear Higgs detection, it is important to fit the original electron accelerator energy depending on the Higgs mass, to set the polarization of the photon beams and to apply the efficient $b$ quark tagging method.

C. Slotta, J. Sollfrank, U. Heinz

It was recently found that in sulphur-induced nuclear collisions at 200 A GeV the observed strange hadron abundances can be explained within a thermodynamic model where baryons and mesons separately are in a state of relative chemical equilibrium, with overall strangeness being slightly undersaturated, but distributed among the strange hadron channels accord

V. Berezinsky, A. Dolgov, M. Kachelriess

We study pion curvature radiation by a proton, i.e. pion emission by a proton moving along a curved trajectory. We suggest an approximate semiclassical solution and the exact solution for which we assume that a proton moves in a fictitious magnetic field with the Larmor radius equal to the curvature radius of the real trajectory. As possible application we c

DIRK GRAUDENZ

Some topics related to Standard Model Higgs boson physics at the Large Hadron Collider are reviewed. Emphasis is put on an overview of QCD corrections to Higgs boson decay and production processes. (Invited talk presented at the XXXth Rencontres de Moriond, Les Arcs 1800, March 19-26, 1995; to appear in the proceedings of the conference.)

Satchidananda Naik

A non-perturbative mass of $0.2719 g^2 T$ is generated for the magnetic sector of the $SU(2)$ gauge theory at high temperature due to the condensation of Polyakov \cite{Pol} monopole and antimonopole which form a magnetic glue ball. String tension for the spatial wilson loop is calculated which is of the same order of magnitude and has same temperature depen

M. Laine

The essential features of the high-temperature electroweak phase transition are contained in a three-dimensional super-renormalizable effective field theory. We calculate the exact counterterms needed for lattice simulations of the SU(2)-part of this theory. Scalar fields in both fundamental and adjoint representations are included. The three-dimensional U(1