January 1997 arXiv papers — page 11

Paolo Pasti, Dmitri Sorokin, Mario Tonin

We propose a complete Born-Infeld-like action for a bosonic 5-brane with the worldvolume chiral field in a background of gravitational and antisymmetric gauge fields of D=11 supergravity. When the five-brane couples to a three-rank antisymmetric gauge field local worldvolume symmetries of the five-brane require the addition to the action of an appropriate We

Martin J. Howard, Uwe C. Täuber

Reaction-diffusion systems which include processes of the form A+A->A or A+A->0 are characterised by the appearance of `imaginary' multiplicative noise terms in an effective Langevin-type description. However, if `real' as well as `imaginary' noise is present, then competition between the two could potentially lead to novel behaviour. We thus inv

Ulf-G. Meißner, S. Steininger

We consider the chiral expansion of the octet baryon magnetic moments in heavy baryon chiral perturbation theory including all terms which are of order $q^4$. These terms are formally of quadratic order in the quark masses. We show that despite the large non-analytic quark mass corrections to the Coleman-Glashow relations at order $q^3$, including all analyt

Masao Mori, Yuzuru Yoshii, Takuji Tsujimoto, Ken'ichi Nomoto

We simulate the dynamical and chemical evolution of a dwarf galaxy embedded in a dark matter halo, using a three-dimensional N-body/SPH simulation code combined with stellar population synthesis. The initial condition is adopted in accord with a $10^{10}M_\odot$ virialized sphere in a 1-sigma CDM perturbation which contains 10% baryonic mass. A supersonic sp

Q. P. Liu, M. Manas

In this paper we present a vectorial Darboux transformation, in terms of ordinary determinants, for the supersymmetric extension of the Korteweg-de Vries equation proposed by Manin and Radul. It is shown how this transformation reduces to the Korteweg-de Vries equation. Soliton type solutions are constructed by dressing the vacuum and we present some relevan

Q. P. Liu, M. Manas

Darboux transformation is reconsidered for the supersymmetric KdV system. By iterating the Darboux transformation, a supersymmetric extension of the Crum transformation is obtained for the Manin-Radul SKdV equation, in doing so one gets Wronskian superdeterminant representations for the solutions. Particular examples provide us explicit supersymmetric extens

V. B. Kuznetsov, F. W. Nijhoff, E. K. Sklyanin

We construct a separation of variables for the classical n-particle Ruijsenaars system (the relativistic analog of the elliptic Calogero-Moser system). The separated coordinates appear as the poles of the properly normalised eigenvector (Baker-Akhiezer function) of the corresponding Lax matrix. Two different normalisations of the BA functions are analysed. T

C. A. Tracy, H. Widom

The small t asymptotics of a class of solutions to the 2D cylindrical Toda equations is computed. The solutions, q_k(t), have the representation q_k(t) = log det(I-lambda K_k) - log det(I-lambda K_{k-1}) where K_k are integral operators. This class includes the n-periodic cylindrical Toda equations. For n=2 our results reduce to the previously computed asymp

Gergely Bana, Thomas Durt

Many argued (Accardi and Fedullo, Pitowsky) that Kolmogorov's axioms of classical probability theory are incompatible with quantum probabilities, and this is the reason for the violation of Bell's inequalities. Szabó showed that, in fact, these inequalities are not violated by the experimentally observed frequencies if we consider the real, ``effecti

Carsten Binnenhei

We study the semigroup of Bogoliubov endomorphisms of the canonical commutation relations which give rise to representations of the Cuntz algebra $O_\infty$ on Fock space and describe the corresponding Cuntz algebra generators in detail.

Carsten Binnenhei

We exhibit a family of *-isomorphisms mapping the CAR algebra onto its even subalgebra.

Carsten Binnenhei

The implementation of non-surjective Bogoliubov transformations in Fock states over CAR algebras is investigated. Such a transformation is implementable by a Hilbert space of isometries if and only if the well-known Shale-Stinespring condition is met. In this case, the dimension of the implementing Hilbert space equals the square root of the Watatani index o

A. J. Baltz

An exact solution of the time-dependent Dirac equation for ionization and pair production induced by ultrarelativistic heavy ion collisions is presented. Exact transition probabilities, equivalent to those that would be obtained in an untruncated basis coupled channels calculation, are presented. Exact bound-electron positron pair production probabilities ar

J. F. Babb

Theoretical investigations of the hyperfine structure of the hydrogen molecular ion (one electron and two protons) are discussed. The nuclear spin-rotation interaction has been found to be of the same sign as in the hydrogen molecule and the hyperfine transition frequencies can be accurately predicted. With measurements of the hyperfine structure of the deut

John David Crawford, K. T. R. Davies

The onset of collective behavior in a population of globally coupled oscillators with randomly distributed frequencies is studied for phase dynamical models with arbitrary coupling; the effect of a stochastic temporal variation in the frequencies is also included. The Fokker-Planck equation for the coupled Langevin system is reduced to a kinetic equation for

V. S. Lac, J. P. Elliott, J. A. Evans

Wave-functions from the newly proposed O(18) coupling scheme in IBM-3 are compared with those from a numerical calculation fitted to some Ni, Zn, Ge and Se nuclei.

Emil J. Straube

We show subellipticity of the d-bar Neumann problem on domains with Lipschitz boundary in the presence of plurisubharmonic functions with Hessians of algebraic growth. In particular, a subelliptic estimate holds near a point where the boundary is piecewise smooth of finite type.

Douglas Singleton

A theory containing both electric and magnetic charges is formulated using two vector potentials, $A_μ$ and $C_μ$. This has the aesthetic advantage of treating electric and magnetic charges both as gauge charges, but it has the experimental disadvantage of introducing a second massless gauge boson (the ``magnetic'' photon) which is not observed. This

Douglas Singleton

By treating magnetic charge as a gauge symmetry through the introduction of a ``magnetic'' pseudo four-vector potential, it is shown that it is possible, using the 't Hooft-Polyakov construction, to obtain a topological electric charge. The mass of this electrically charged particle is found to be on the order of {1 / 137} M_W as opposed to the m

Wolfgang Junker

It is explained how techniques from microlocal analysis can be used to settle some long-standing questions that arise in the study of the interaction of quantum matter fields with a classical gravitational background field.

Luis J. Boya, Antonio J. Segui-Santonja

We show that the topological charge of the n-soliton solution of the sine-Gordon equation n is related to the genus g > 1 of a constant negative curvature compact surface described by this configuration. The relation is n=2(g-1), where n is even. The moduli space of complex dimension B(g)=3(g-1) corresponds precisely to the freedom to choosing the configurat

T. G. Steele, S. Alavian, J. Kwan

Fundamental inequalities for QCD sum-rules are applied to resolve a paradox recently encountered in a sum-rule calculation. This paradox was encountered in a toy model known to be free of resonances that yields an apparent resonance using a standard sum-rule stability analysis. Application of the inequalities does not support the existence of a well defined

O. D. Chernavskaya

The problem of entropy S and baryon number N_B conservation in phase transitions from deconfined phases (QGP and Q) to hadronic matter H is considered. It is shown that standard construction of both first order phase transitions, H-Q as well as Q-QGP implies a discontinuous structure of entropy per baryon S/N_B when crossing phase boundary; this results in i

J. Lopez, D. Nanopoulos

We discuss the highlights of recent developments in no-scale supergravity and flipped SU(5), especially in the context of a very light gravitino scenario that may explain the puzzling CDF e+e+gamma+gamma+E_T,miss event. We update the status of both subjects and discuss the impact of the latest experimental constraints from LEP and the Tevatron. We also comme

A. Pich

The Standard Model requires the three known leptonic families to have identical couplings to the gauge bosons. The present experimental tests on lepton universality are reviewed, both for the charged and neutral current sectors. Our knowledge about the Lorentz structure of the $l^-\toν_l l'^-\barν_{l'}$ transition amplitudes is also discussed.

Andrey G. Grozin, Matthias Neubert

We discuss the renormalization of local, scalar and pseudoscalar dimension-5 operators containing a heavy and a light quark field at scales below the heavy-quark mass, using the formalism of the heavy-quark effective theory (HQET). We calculate the anomalous dimensions of these operators and their mixing to one-loop order. We also perform the one-loop matchi

Yoshio Koide

Flavor-changing neutral currents (FCNC) are studied on the basis of a ``democratic seesa'' mass matrix model, which yields a singular enhancement of the top-quark mass m_t and can give reasonable quark masses and CKM matrix elements. The most exciting aspect of the model is that the structure of the $6 \times 6$ right-handed fermion mixing matrix in

Yasuhiro Okada

Several topics related to phenomenology of the Higgs sector in the supersymmetric standard model are reviewed. The upper bound of the lightest Higgs mass in the minimal supersymmetric standard model as well as extended version of it is discussed and it is shown that an $e^+ e^-$ linear collider with $\sqrt{s}\sim300 - 500$ GeV can find at least one Higgs bos

R. Santos, A. Barroso

We perform the complete one-loop renormalization of a general two-Higgs-doublet model. We present all the vertices for this model including the ones in the scalar sector and calculate all the counterterms of the theory.

M. S. Alam

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for jet-jet masses less than 7 GeV.

J. William Gary

Differences between the properties of gluon and quark jets have been convincingly established by experiments at LEP. Quantitative tests of QCD analytic predictions for these differences have not been possible, however, because of differences between the theoretical and experimental definitions of the jets and event samples. Here, a new method to compare gluo

Cosimo Stornaiolo, Giampiero Esposito

The properties of multimomentum maps on null hypersurfaces, and their relation with the constraint analysis of General Relativity, are described. Unlike the case of spacelike hypersurfaces, some constraints which are second class in the Hamiltonian formalism turn out to contribute to the multimomentum map.

Maurice H. P. M. van Putten

A second-order numerical implementation is given for recently derived nonlinear wave equations for general relativity. The Gowdy T$^3$ cosmology is used as a test bed for studying the accuracy and convergence of simulations of one-dimensional nonlinear waves. The complete freedom in space-time slicing in the present formulation is exploited to compute in the

Claus Kiefer

I discuss the semiclassical approximation for the Wheeler-DeWitt equation when applied to the CGHS model and spherically symmetric gravity. Special attention is devoted to the issues of Hawking radiation, decoherence of semiclassical states, and black hole entropy.

Victor Berezin

Two different ways of quantizing the relativistic Hamiltonian for radial motion in the field of Coulomb-like potential are compared. The results depend slightly on choice of time. In the case of Lorentzian time a Sommerfeld spectrum is recovered. Application to quantum black holes gives a sqrt{n} mass spectrum with about the same numerical factors.

S. Jhingan, P. S. Joshi

We study here the structure of singularity forming in gravitational collapse of spherically symmetric inhomogeneous dust. Such a collapse is described by the Tolman-Bondi-Lema{î}tre metric, which is a two-parameter family of solutions to Einstein equations, characterized by two free functions of the radial coordinate, namely the `mass function' F(r) and

S. Massar, R. Parentani

Hawking radiation is derived from the existence of a euclidean instanton which lives in the euclidean black hole geometry. Upon taking into account the gravitational field of the instanton itself, its action is exactly equal to one quarter the change in the horizon area. This result also applies to the Schwinger process, the Unruh process, and particle creat

Stephen J. Summers

We provide an overview of the connections between Bell's inequalities and algebraic structure.

D. Z. Liu, X. C. Xie

We study the localization properties in coupled double quantum wells with an in-plane magnetic field. The localization length is directly calculated using a transfer matrix technique and finite size scaling analysis. We show that the system maps into a 2D XY model and undergoes a disorder driven Kosterlitz-Thouless type metal-insulator transition depending o

M. I. Lubin, O. Heinonen, M. D. Johnson

We have developed an ensemble density functional theory which includes spin degrees of freedom for nonuniform quantum Hall systems. We have applied this theory using a local-spin-density approximation to study the edge reconstruction of parabolically confined quantum dots. For a Zeeman splitting below a certain critical value, the edge of completely polarize

S. Das Sarma, P. Punyindu

We study statistical scale invariance and dynamic scaling in a simple solid-on-solid 2+1 - dimensional limited mobility discrete model of nonequilibrium surface growth, which we believe should describe the low temperature kinetic roughening properties of molecular beam epitaxy. The model exhibits long-lived ``transient'' anomalous and multiaffine dyn

Shanhui Xiong, N. Read, A. Douglas Stone

We consider the bilocal conductivity tensor, the two-probe conductance and its fluctuations for a disordered phase-coherent two-dimensional system of non-interacting electrons in the presence of a magnetic field, including correctly the edge effects. Analytical results are obtained by perturbation theory in the limit $σ_{xx} \gg 1$. For mesoscopic systems th

Joel Feldman, Manfred Salmhofer, Eugene Trubowitz

Regularity of the deformation of the Fermi surface under short-range interactions is established for all contributions to the RPA self-energy (it is proven in an accompanying paper that the RPA graphs are the least regular contributions to the self-energy). Roughly speaking, the graphs contributing to the RPA self-energy are those constructed by contracting

M K Hassan

We present a number models describing the sequential deposition of a mixture of particles whose size distribution is determined by the power-law $p(x) \sim αx^{α-1}$, $x\leq l$ . We explicitly obtain the scaling function in the case of random sequential adsorption (RSA) and show that the pattern created in the long time limit becomes scale invariant. This pa

R. Eder, O. Stoica, G. A. Sawatzky

We present a simple theory for the description of the single particle excitations in the Kondo lattice model. Thereby we derive an `effective Hamiltonian' which describes the coherent propagation of single particle-like fluctuations on a strong coupling background. Even for f-electrons which are replaced by Kondo-spins, the resulting spectral function ob

Alain Chiolero, Daniel Loss

We study macroscopic quantum coherence (MQC) in small ferrimagnets. Through semi-classical calculations we show that even a small uncompensated moment has a drastic effect on MQC. In particular, there is a rapid crossover to a regime where the MQC tunnel splitting is equal to that obtained for a ferromagnet, even though the system is still an antiferromagnet

Giorgio Parisi

Here we review the approach to glassy systems based on the replica method and we introduce the main ingredients of replica symmetry breaking. We explain why the replica method has been successful in spin glass and why it should be successful for real glasses.

C. A. Tracy, H. Widom

Using exact results from the theory of completely integrable systems of the Painleve/Toda type, we examine the consequences for the theory of polyelectrolytes in the (nonlinear) Poisson-Boltzmann approximation.

Toru Ohira

We investigate analytically and numerically the statistical properties of a random walk model with delayed transition probability dependence (delayed random walk). The characteristic feature of such a model is the oscillatory behavior of its correlation function. We investigate a model whose transient and stationary oscillatory behavior is analytically tract

P. H. Song, Doochul Kim

Bifractal is a highly anisotropic structure where planar fractals are stacked to form a 3-dimensional lattice. The localization lengths along fractal structure for the Anderson model defined on a bifractal are calculated. The critical disorder and the critical exponent of the localization lengths are obtained from the finite size scaling behavior. The numeri

C. Pich, F. Schwabl

The magnetic phase diagram of the quasi one-dimensional spinchain system CsNiF$_3$ below the Néel temperature is determined. For magnetic fields perpendicular to the spin chains incommensurate phases are predicted. From linear spin-wave theory we obtain the instability line of the paramagnetic phase as a function of the strength and the direction of the fiel

Biman B. Nath

[Abridged abstract:] Recent numerical simulations show that many $\lyal$ absorption lines of column densities $\nha \la 10^{15}$ cm$^{-2}$ are produced in transient, mini pancakes. Such pancakes are modeled here, approximating the initial perturbation leading to the formation of the pancake as a single sinusoidal wave. The density and temperature profiles of

Takahiro Tanaka, Misao Sasaki

We give the initial spectrum of quantized gravitational waves in the context of the one-bubble open inflationary universe scenario. In determining the quantum state after the bubble nucleation we adopt the prescription to require the analyticity of positive frequency functions in half of the Euclidean extension of the background O(3,1)-symmetric spacetime. W

D. Sprayberry, C. D. Impey, M. J. Irwin, G. D. Bothun

We present a luminosity function for low surface brightness (LSB) galaxies identified in the APM survey of Impey et al 1996. These galaxies have central surface brightnesses in B in the range 22 < mu < 25. Using standard maximum-likelihood estimators, we determine that the best-fit Schechter function parameters for this luminosity function (LF) are alpha = -

Enrique Vazquez-Semadeni

In this course we review the theory of incompressible homogeneous turbulence at an elementary level, and discuss the similarities and differences expected in the compressible case, relevant to the interstellar medium and molecular clouds. We stress that a general definition of turbulence applicable to the compressible case should not rely on the Kolmogorov $

Enrique Vazquez-Semadeni

The Virial Thoerem is a mathematical expression obtained from the equation of motion for a fluid, which describes the energy budget of particular regions within the flow. This course reviews the basic theory leading to the Virial Theorem, discusses its applicability and limitations, and then summarizes observational results concerning the physical and statis

G. M. D&#39;Ariano

Homodyne tomography - i. e. homodyning while scanning the local oscillator phase - is now a well assessed method for ``measuring&#39;&#39; the quantum state. In this paper I will show how it can be used as a kind of universal detection, for measuring generic field operators, however at expense of some additional noise. The general class of field operators th

Richard Dawid, Serguei Reznov

We show that the effective theory of a supersymmetric model can violate SUSY at the level of dimension six operators and higher. This phenomenon occurs in gauge theories which involve heavy vector-superfields and different mass scales. It appears in SUSY GUT theories and is important in models of propagating Higgs boundstates.

Ruth Gregory, Caroline Santos

We examine the metric of an isolated self-gravitating abelian-Higgs vortex in dilatonic gravity for arbitrary coupling of the vortex fields to the dilaton. We look for solutions in both massless and massive dilaton gravity. We compare our results to existing metrics for strings in Einstein and Jordan-Brans-Dicke theory. We explore the generalization of Bogom

J. Ambjorn, K. N. Anagnostopoulos

We show that there exists a divergent correlation length in 2d quantum gravity for the matter fields close to the critical point provided one uses the invariant geodesic distance as the measure of distance. The corresponding reparameterization invariant two-point functions satisfy all scaling relations known from the ordinary theory of critical phenomena and

T. Papenbrock, T. H. Seligman, H. A. Weidenmueller

We present a novel extension of the concept of scars for the wave functions of classically chaotic few-body systems of identical particles with rotation and permutation symmetry. Generically there exist manifolds in classical phase space which are invariant under the action of a common subgroup of these two symmetries. Such manifolds are associated with high

Joy Christian

Cartan&#39;s spacetime reformulation of the Newtonian theory of gravity is a generally-covariant Galilean-relativistic limit-form of Einstein&#39;s theory of gravity known as the Newton-Cartan theory. According to this theory, space is flat, time is absolute with instantaneous causal influences, and the degenerate `metric&#39; structure of spacetime remains

S. L. Yakovlev, I. N. Filikhin

The cluster reduction method for the Yakubovsky equations in configuration space is used for calculations of zero-energy scattering in four-nucleon system. The main idea of the method consists in making use of expansions for the Yakubovsky amplitudes onto the basis of the Faddeev components for the two-cluster sub-Hamiltonian eigenfunctions. The expansions r

Alexey Onufriev, Brad Marston

Enlarged symmetry characterized by the group SU(4) can be realized in isolated semiconducting quantum dots. A Hubbard model then describes a pillar array of coupled dots and at half-filling the system can be mapped onto an SU(4) spin chain. The physics of these new structures is rich as novel phases are attainable. The spins spontaneously dimerize and, by us

G. M. D&#39;Ariano, C. Macchiavello

In the two papers [T. Kiss, U. Herzog, and U. Leonhardt, Phys. Rev. A 52, 2433 (1995); U. Herzog, Phys. Rev. A 53, 1245 (1996)] with titles similar to the one given above, the authors assert that in some cases it is possible to compensate a quantum efficiency $η\leq 1/2$ in quantum-state measurements, violating the lower bound 1/2 proved in a preceding paper

Mariusz P. Dabrowski, Claus Kiefer

We discuss in detail how to consistently impose boundary conditions in quantum string cosmology. Since a classical time parameter is absent in quantum gravity, such conditions must be imposed with respect to intrinsic variables. Constructing wave packets for minisuperspace models from different tree-level string effective actions, we explain in particular th

Indrani Bose, Asimkumar Ghosh

The experimental observation of a spin-gap in the antiferromagnetic spin-1/2 compound $CaV_4O_9$ has been attributed to the formation of a plaquette resonating-valence-bond (PRVB) state in the underlying 1/5-depleted square lattice. We construct a spin-1/2 model on the 1/5-depleted lattice for which the PRVB state can be shown to be the exact ground state in

K. Golec-Biernat, J. Kwieciński, A. Szczurek

A detailed analysis of semi-exclusive diffractive processes in e-p DIS at HERA, with the diffractive final states in the forward direction is presented. The contributions of the subleading f_2, ω, a_2, ρreggeons and the pion exchanges to the diffractive structure function with the forward proton or neutron are estimated. It is found that the (a_2,ρ) reggeons

V. N. Melekhin

It is shown that change in transverse momentum of a relativistic particle, crossing an accelerating cavity parallel to its axis, may be presented as an integral over trajectory, the integrand of which is proportional to the component of magnetic field parallel to this axis. The changes in two transversal components of momentum are equal in value but opposite

O. Panella, C. Carimalo, Y. N. Srivastava, A. Widom

We study in detail the contribution of heavy composite Majorana neutrinos to neutrino-less double beta decay. Our analysis confirms the result of a previous estimate by two of the authors. Excited neutrinos couple to the electroweak gauge bosons through a magnetic type effective Lagrangian. The relevant nuclear matrix element is related to matrix elements av

J. -M. Drezet

I give a way to construct moduli spaces of complexes, as quotients of open subsets of the space of all complexes by the product of the groups of automorphisms of the terms.

D. Matsushita

For a flat family of Du Val singularities, we can take a simultaneous resolution after finite base change. It is an interesting problem to consider this analogy for a flat family of higher dimensional canonical singularities. In this note, we consider an existence of simultaneous terminalization for K. Altmann&#39;s homogeneous toric deformation whose centra

Shin&#39;ichi Nojiri, Sergei D. Odintsov

We study the effective action in 2D dilaton-Maxwell quantum gravity. Working with the one-loop renormalizable subset of such theories, we construct the improved effective Lagrangian which contains curvature under logarithm. This effective Lagrangian leads to new classical dilatonic gravity inspired by quantum effects. The static black holes (BH) solutions wh

Feng Yuan, Cong-Feng Qiao, Kuang-Ta Chao

The calculation of D-wave charmonium prodution rates in B meson deacys under the NRQCD factorization formalism is presented. We find that inclusion of the color-octet contributions permits us to detect the D-wave charmonium states in B decays at present experimental facilities. The same amount signals of 2^{--} D-wave state as that of ψ&#39; could be observe

Pavel Etingof, Israel Gelfand, Vladimir Retakh

We integrate nonabelian Toda field equations for root systems of types A, B, C, for functions with values in any associative algebra. The solution is expressed via quasideterminants. In the appendix we review some results concerning nonabelian soliton equations.

G. M. D&#39;Ariano, N. Sterpi, C. Macchiavello

We study both systematic and statistical errors in radiation density matrix measurements. First we estimate the minimum number of scanning phases needed to reduce systematic errors below a fixed threshold. Then, we calculate the statistical errors, intrinsic in the procedure that gives the density matrix. We present a detailed study of such errors versus the

M. Kapranov

Let A be an abelian category of finite type and homological dimension 1. Then by results of Green R(A), the extended Hall-Ringel algebra of A, has a natural Hopf algebra structure. We consider its Heisenberg double Heis(A) and study its relation with D(A), the derived category of A. We show that Heis(A) can be viewed as a &#34;Hall algebra&#34; of D^{0,1}(A)

G. A. Kotel&#39;nikov

An algorithm for studing the symmetrical properties of the partial differential equation of the type Lu=0 is proposed. By symmetry of this equation we mean the operators Q satisfying commutational relations of order p more than p=1 on the solutions u: [L...[L,Q]...]u=0. It is shown, that within the framework of the proposed method with p=2 the relativistic D

A. G. Rossberg, L. Kramer

For over 25 years it is known that the roll structure of electroconvection (EC) in the dielectric regime in planarly aligned nematic liquid crystals has, after a transition to defect chaos, the tendency to form chevron structures. We show, with the help of a coarse-grained model, that this effect can generally be expected for systems with spontaneously broke

J. Piekarewicz, A. J. Sarty, M. Benmerrouche

We study coherent eta-photoproduction from nuclei in a relativistic impulse approximation approach. For the elementary production amplitude we use a standard relativistic parameterization based on a set of four Lorentz- and gauge-invariant amplitudes. The photonuclear amplitude is evaluated without recourse to a nonrelativistic reduction; the full relativist

R. Cenni, F. Conte, P. Saracco

The splitting between the charge-longitudinal and spin-transverse responses is explained in a model whose inputs are the effective interactions in the particle-hole channels in the first order boson loop expansion. The interplay between $ω$-meson exchange and box diagrams mainly governs the longitudinal response, while in the transverse one the direct $Δ$ ex

C. A. da Rocha, G. Krein, L. Wilets

Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff, and Wilets (BPW). These ghosts violate basic theorems of quantum field theory and their origin is related to the ultr

Yukinori Nagatani

We formulate field theories in fractal space and show the phase diagrams of the coupling versus the fractal dimension for the dynamical symmetry breaking. We first consider the 4-dimensional Gross-Neveu (GN) model in the (4-d)-dimensional randomized Cantor space where the fermions are restricted to a fractal space by the high potential barrier of Cantor frac

Hitoshi Konno

Following the work with Jimbo and Miwa, we introduce a certain degeneration of the elliptic algebra $A_{q,p}(\widehat{sl_2})$ and its boson realization. We investigate its rational limit. The limit is the central extension of the Yangian double DY(sl_2) at level one. We give a new boson realization of it. Based on these algebras, we reformulate the Smirnov&#

Pawel O. Mazur

The gravitational measure on an arbitrary topological three-manifold is constructed. The nontrivial dependence of the measure on the conformal factor is discussed. We show that only in the case of a compact manifold with boundary the measure acquires a nontrivial dependence on the conformal factor which is given by the Liouville action. A nontrivial Jacobian

Remo Garattini

We investigate the possibility of computing energy by means of operators associated to the Wheeler-DeWitt equation. By choosing three dimensional wormholes as a framework, we apply such calculation scheme to the black hole pair creation. We compare our results with the recent ones appeared in the literature.

H. L. Lai, W. K. Tung

Recent accurate data on F_2(x,Q) and on F_2^c(x,Q) from HERA at small-x require a more precise treatment of charm production in the global QCD analysis of parton distributions. We improve on existing global analyses by implementing the leptoproduction formalism of Aivazis et al. which represents a natural generalization of the conventional zero mass QCD part

Anja Werthenbach, L. M. Sehgal

The energy spectrum of leptons, produced by the decay of one or both W&#39;s in the reaction $e^+e^- \to W^+W^-$, is a significant probe of the helicity structure of this process. We calculate the energy spectrum $d σ/d E$ of a single decay lepton, as well as the two-dimensional energy distribution $d σ/d E_+dE_-$. We then consider a possible strong final st

M. Hirsch, H. V. Klapdor-Kleingrothaus, S. G. Kovalenko

We prove a general low-energy theorem establishing a generic relation between the neutrino Majorana mass and the superpartner sneutrino B-L-violating &#34;Majorana&#34;-like mass term. The theorem states that, if one of these two quantities is non-zero the other one is also non-zero and, vice versa, if one of them vanishes the other vanishes, too. The theore

M. Diehl

The cross section for the diffractive reaction gamma* + p -> c cbar + p with a real or virtual photon is calculated in the nonperturbative two-gluon exchange model of Landshoff and Nachtmann. Numerical predictions are given for cross sections and spectra at typical HERA values of c.m. energy and photon virtuality. The contribution of charm to the diffractive

Cong-feng Qiao, Feng Yuan, Kuang-Ta Chao

We present a calculation of the leading order QCD fragmentation functions for gluons to split into spin-triplet D-wave quarkonia. We apply them to evaluate the gluon fragmentation contributions to inclusive ^3D_J quarkonium production at large transverse momentum processes like the Tevatron and find that the D-wave quarkonia, especially the charmonium 2^{--}

J. Cox, W. Franzki, J. Jersak, C. B. Lang

We investigate the continuum limit of the gauge-ball spectrum in the four-dimensional pure U(1) lattice gauge theory. In the confinement phase we identify various states scaling with the correlation length exponent $ν\simeq 0.35$. The square root of the string tension also scales with this exponent, which agrees with the non-Gaussian fixed point exponent rec

The E143 Collaboration

We have measured the proton and deuteron spin structure functions g_1^p and g_1^d in the region of the nucleon resonances for W^2 < 5 GeV^2 and $Q^2\simeq 0.5$ and $Q^2\simeq 1.2$ GeV^2 by inelastically scattering 9.7 GeV polarized electrons off polarized $^{15}NH_3$ and $^{15}ND_3$ targets. We observe significant structure in g_1^p in the resonance region.

Steve Kettell

Recent results from the first phase of the E787 experiment and an update on the current status are presented. From the first phase the limit on the K+ -> pi+ nu nu (pnn) branching ratio is BR(pnn) < 2.4e-9 (90%CL). An observation of the decay K+ -> pi+ mu mu has been made using two separate techniques. An observation of the decay K+ -> pi+ gamma gamma has be

Michael Schmelling

The current status of measurements of the strong coupling constant from different reactions is reviewed. Including new results presented at the 1996 ICHEP conference, a global average alpha_s(Mz) = 0.118 +- 0.003 is obtained.

Thomas Kloesch

We present a classification of all global solutions for generalized 2D dilaton gravity models (with Lorentzian signature). While for some of the popular choices of potential-like terms in the Lagrangian, describing, e.g., string inspired dilaton gravity or spherically reduced gravity, the possible topologies of the resulting spacetimes are restricted severel

Frederic Mila, Didier Poilblanc

The main point of Clarke and Strong&#39;s comment, namely that our results concerning the effect of integrability on the hopping of electrons between chains are probably not related to the notion of coherence proposed in \cite{clarke}, is important and well taken. In fact, we have already stressed in our work that integrability affects the intermediate-time

Siegfried Clar, Klaus Schenk, Franz Schwabl

We investigate a forest-fire model with the density of empty sites as control parameter. The model exhibits three phases, separated by one first-order phase transition and one &#39;mixed&#39; phase transition which shows critical behavior on only one side and hysteresis. The critical behavior is found to be that of the self-organized critical forest-fire mod

C. -T. Liang, J. E. F. Frost, M. Y. Simmons, D. A. Ritchie

We have measured the low-temperature transport properties of a high-mobility front-gated GaAs/Al_{0.33}Ga_{0.67}As heterostructure. By changing the applied gate voltage, we can vary the amount of disorder within the system. At a Landau level filling factor $ν=1/2$, where the system can be described by the composite fermion picture, we observe a crossover fro

C. -T. Liang, I. M. Castleton, J. E. F. Frost, C. H. W. Barnes

We have measured the low-temperature transport properties of a quantum dot formed in a one-dimensional channel. In zero magnetic field this device shows quantized ballistic conductance plateaus with resonant tunneling peaks in each transition region between plateaus. Studies of this structure as a function of applied perpendicular magnetic field and source-d