April 1996 arXiv papers — page 12

V. I. Berezhiani, S. M. Mahajan

It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap semiconductors (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas.

Horacio M. Pastawski, Patricia R. Levstein, Gonzalo Usaj

The evolution of local spin polarization in finite systems involves interference phenomena that give rise to {\bf quantum dynamical echoes }and non-ergodic behavior. We predict the conditions to observe these echoes by exploiting the NMR sequences devised by Zhang et al. [Phys. Rev. Lett. {\bf % 69}, 2149 (1992)], which uses a rare $^{13}$C as {\bf local pro

M. E. Garcia, D. Reichardt, K. H. Bennemann

The ultrafast relaxation of small clusters immediately after ionization is studied. For small Hg$_n$ clusters we determine the fragmentation-time distributions induced by ionization. A dramatic change of the fragmentation behaviour occurs when the temperature before ionization reaches the melting point of the neutral clusters. The ultrafast dynamics depends

Jean-Luc Thiffeault, Wendell Horton

A method is presented for making finite Fourier mode truncations of the Rayleigh--Benard convection system that preserve invariants of the full partial differential equations in the dissipationless limit. These truncations are shown to have no unbounded solutions and provide a description of the thermal flux that has the correct limiting behavior in a steady

P. Garbaczewski, G. Kondrat, R. Olkiewicz

We explore a connection of the deterministically forced Burgers equation for local velocity fields with probabilistic solutions of the Schrödinger boundary data problem. An issue of deducing the most likely interpolating dynamics from the given initial and terminal probability density data is here investigated to give account of the perturbation by external

E. J. M. Colbert, S. A. Baum, J. F. Gallimore, C. P. O'Dea

We present deep images of the kpc-scale radio continuum emission in 14 edge-on galaxies (ten Seyfert and four starburst galaxies). Observations were taken with the VLA at 4.9~GHz (6~cm). The Seyfert galaxies were selected from a distance-limited sample of 22 objects (defined in paper~I). The starburst galaxies were selected to be well-matched to the Seyferts

L. J. Storrie-Lombardi, R. G. McMahon, M. J. Irwin, C. Hazard

The APM multicolor survey for bright z > 4 objects, covering 2500 deg^2 of sky to m(R)~19, resulted in the discovery of thirty-one quasars with z > 4. High signal-to-noise optical spectrophotometry at 5A resolution has been obtained for the twenty-eight quasars easily accessible from the northern hemisphere. These spectra have been surveyed to create new sam

A. N. Taylor, A. J. S. Hamilton

We present an expression for the nonlinear evolution of the cosmological power spectrum based on following Lagrangian trajectories. This is simplified using the Zel'dovich approximation to trace particle displacements, assuming Gaussian initial conditions. The model is found to exhibit the transfer of power from large to small scales expected in self- gr

W. Dröge, D. Ruffolo, B. Klecker

We have found evidence for fluxes of energetic electrons in interplanetary space on board the ISEE-3 spacecraft which we interpret as the decay products of neutrons generated in a solar flare on 1980 June 21. The decay electrons arrived at the s/c shortly before the electrons from the flare and can be distinguished from the latter by their distinctive energy

Mark J. Henriksen, Raymond E. White

We have analyzed X-ray spectra from six galaxy clusters which contain cooling flows: A85, A478, A1795, A2142, A2147, & A2199. The X-ray spectra were taken with the HEAO1-A2 Medium and High Energy Detectors and the Einstein Solid State Spectrometer. For each cluster, we simultaneously fit the spectra from these three detectors with models incorporating one or

A. Shafiekhani, M. R. Rahimi Tabar

It is shown explicitly that the correlation functions of Conformal Field Theories (CFT) with the logarithmic operators are invariant under the differential realization of Borel subalgebra of $\W_\infty$-algebra. This algebra is constructed by tensor-operator algebra of differential representation of ordinary $sl(2,C)$. This method allows us to write differen

Cheuk-Yin Wong, Lali Chatterjee

Lowest-order cross sections for $q\bar q$ production and annihilation can be approximately corrected for higher-order QCD effects by using a corrective $K$-factor. For energies where quark masses cannot be ignored, the $K$-factor is dominated by the wave function distortion arising from the initial- or final-state interaction between the quark and the antiqu

Willy Fischler, Sonia Paban, Moshe Rozali

We develope a formalism for the scattering off D-branes that includes collective coordinates. This allows a systematic expansion in the string coupling constant for such processes, including a worldsheet calculation for the D-brane's mass.

J. D. Larwood, R. P. Nelson, J. C. B. Papaloizou, C. Terquem

We present the results of non linear, hydrodynamic simulations, in three dimensions, of the tidal perturbation of accretion discs in binary systems where the orbit is circular and not necessarily coplanar with the disc mid-plane. The accretion discs are assumed to be geometrically thin, and of low mass relative to the stellar mass so that they are governed b

Alexander Fel'shtyn

The paper consists of four parts. Part I presents a brief survey of the Nielsen fixed point theory. Part II deals with dynamical zeta functions connected with Nielsen fixed point theory. Part III is concerned with congruences for the Reidemeister and Nielsen numbers. Part IV deals with the Reidemeister torsion . In Chapter 2 we prove that the Reidemeister ze

B. Rosenow, R. Oppermann

We show that tricritical points displaying unusal behaviour exist in phase diagrams of fermionic Ising spin glasses as the chemical potential or the filling assumes characteristic values. Exact results for infinite range interaction and a one loop renormalization group analysis of thermal tricritical fluctuations for finite range models are presented. Surpri

Andreas Wirzba, Per. E Rosenqvist

We investigate the scattering off three nonoverlapping disks equidistantly spaced along a line in the two-dimensional plane with the radii of the outer disks equal and the radius of the inner disk varied. This system is a two-dimensional scattering analog to the double-well-potential (bound state) problem in one dimension. In both systems the symmetry splitt

C. Lucchesi, G. Zoupanos

As a motivation, we first recall the possible connection of electric-magnetic duality to finiteness in N=1 super-Yang-Mills theories (SYM). Then, we present the criterion for all-order finiteness (i.e., vanishing of the beta-functions at all orders) in N=1 SYM. Finally, we apply this finiteness criterion to an SU(5) SGUT. The latter turns out to be all-order

S. Forste, A. Kehagias, S. Schwager

We examine non-abelian duality transformations in the open string case. After gauging the isometries of the target space and developing the general formalism, we study in details the duals oftarget spaces with SO(N) isometries which, for the SO(2) case, reduces to the known abelian T-duals. We apply the formalism to electrically and magnetically charged 4D b

L. Jaede, H. V. von Geramb

Motivated by the success of models based on chiral symmetry in NN interactions we investigate self-interacting scalar, pseudoscalar and vector meson fields and their impact for NN forces. We parametrize the corresponding nonlinear field equations and get analytic wavelike solutions. A probability amplitude for the propagation of particle states is calculated

Nguyen Quoc Thang

We prove the stable rationality of almost simple algebraic groups, the connected components of the Dynkin diagram of anisotropic kernel of which contain at most two vertices. The (stable) rationality of many isotropic almost simple groups with small anisotropic kernel and some related results over $p$-adic and arbitrary fields are discussed.

Emilio Torrente-Lujan

Inspired by the atmospheric multi-GeV neutrino data, we consider neutrino flavor mixing matrices which are maximal in a $2\times 2$ subsector. This condition is a strong restriction: the full matrix including complex phases depends essentially on one parameter. The survival probability is an universal function of $L/E$, independent of generation, in the regi

Alexander von Gussich, Per Sundell

We study some natural connections on spaces of conformal field theories using an analytical regularization method. The connections are based on marginal conformal field theory deformations. We show that the analytical regularization preserves conformal invariance and leads to integrability of the marginal deformations. The connections are shown to be flat an

R. P. Lano, V. G. J. Rodgers

It is well known that by using the infinite dimensional symmetries that issue from string theories, one can build 2D geometric field theories. These 2D field theories can be identified with gravitational and gauge anomalies that arise in the presence of background gauge and gravitational anomalies. In this work we consider the background fields as residuum f

Ken Umeno

We prove the non-integrability (non-existence of additional analytic conserved quantities other than Hamiltonian) for Fermi-Pasta-Ulam (FPU) lattices by virtue of Lyapunov-Kovalevskaya- -Ziglin-Yoshida's monodromy method about the variational equations. The key to this analysis is that the normal variational equations along a certain solution happen to b

A. D. Rogava, G. D. Chagelishvili, V. I. Berezhiani

The electrostatic perturbations in an unmagnetized, non-isothermal ($T_i{\ll}T_e$) electron-ion plasma shear flow are considered. New physical effects, arising due to the non-normality of linear dynamics, are described. It is shown that the velocity shear induces the extraction of the mean flow energy by the acoustic perturbations (ion-sound waves). The infl

M. S. Fayache, Y. Y. Sharon, L. Zamick, P. von Neumann-Cosel

The effects of varying the spin-orbit and tensor components of a realistic interaction on $M1$ excitation rates and $B(E2)'s$ are studied on nuclei in the $0p$ and $1s-0d$ shells. Not only the total $M1$ but also the spin and orbital parts separately are studied. The single-particle energies are first calculated with the same interaction that is used bet

R. Nojarov, Amand Faessler, M. Dingfelder

The main features of the $(e,e^{\prime})$ cross sections of low-lying orbital excitations with $K^π = 1^+$ in heavy deformed nuclei are studied in RPA on the example of $^{156}$Gd. The dependence of the DWBA E2 and M1 cross sections on the scattering angle $0^{\circ} < θ< 180 ^{\circ}$ and incident electron energy $E_i < 210$ MeV is analyzed in PWBA. The cro

Karen M. Brucks, John Ringland, Charles Tresser

We define the Farey web --- a collection of loci in the parameter plane of families of simple non-invertible maps of the circle. We prove some results about the arrangement of these loci and their relationships with other dynamically significant features of the parameter plane. The results enable us to provide short proofs for a number of theorems about the

Stefan Leupold, Heribert Weigert

We present a relation which connects the propagator in the radial (Fock-Schwinger) gauge with a gauge invariant Wilson loop. It is closely related to the well-known field strength formula and can be used to calculate the radial gauge propagator. The result is shown to diverge in four-dimensional space even for free fields, its singular nature is however natu

Michael Engelhardt

The problem of a nonrelativistic particle with an internal color degree of freedom, with and without spin, moving in a free random gauge background is discussed. Freeness is a concept developed recently in the mathematical literature connected with noncommuting random variables. In the context of large-N hermitian matrices, it means that the the multi-matrix

Jorge Alfaro, Ivan Kostov

We derive a set of bilinear functional equations of Hirota type for the partition functions of the $sl(2)$ related integrable statistical models defined on a random lattice. These equations are obtained as deformations of the Hirota equations for the KP integrable hierarchy, which are satisfied by the partition function of the ensemble of planar graphs.

R. Caracciolo, M. Frau, A. Lerda, S. Sciuto

We describe the recently introduced method of Algebraic Bosonization of (1+1)-dimensional fermionic systems by discussing the specific case of the Calogero-Sutherland model. A comparison with the Bethe Ansatz results is also presented.

A. K. Mishra, G. Rajasekaran

A complete Fock space representation of the covariant differential calculus on quantum space is constructed. The consistency criteria for the ensuing algebraic structure, mapping to the canonical fermions and bosons and the consequences of the new algebra for the statistics of quanta are analyzed and discussed. The concept of statistical transmutation betwee

A. A. Deriglazov, A. V. Galajinsky

The Green--Schwarz superstring action is modified to include some set of additional (on-shell trivial) variables. A complete constraints system of the theory turns out to be reducible both in the original and in additional variable sectors. The initial $8s$ first class constraints and $8c$ second class ones are shown to be unified with $8c$ first and $8s$ se

Christof Wetterich

We present an exact nonperturbative flow equation for the average action for quarks which incorporates the effects of gluon fluctuations. With suitable truncations this allows one to compute effective multiquark interactions in dependence on an infrared scale $k$. Our method amounts to integrating out the gluons with momenta larger than $k$.

Sanghyeon Chang, Hang Bae Kim

We study the effect of the late decaying saxino (the scalar superpartner of the axion) and find out that there is a possible dark matter solution from a class of supersymmetric extensions of the invisible axion model. In this class of models, the saxino which decays into two axions acts as the late decaying particle which reconciles the cold dark matter mode

A. Bartl, H. Eberl, S. Kraml, W. Majerotto

We discuss pair production and decays of stops, sbottoms, and staus in $e^+e^-$ annihilation in the energy range $\sqrt{s}$ = 500 GeV to 2 TeV. We present numerical predictions within the Minimal Supersymmetric Standard Model for cross sections and decay rates. We study the stop discovery potential for $\sqrt{s}$ = 500 GeV and $10~\fb^{-1}$ integrated lumino

R. L. Jaffe, N. Saito

Plans are underway to measure spin asymmetries at large momentum transfer in hadron hadron collisions at RHIC and elsewhere. Proposals have focused on measuring quark transversity and quark and gluon helicity distributions in the nucleon. These experiments will also provide a strong and simple test of perturbative QCD, namely that ${\cal A}_{TT}/{\cal A}_{LL

B. Ananthanarayan, P. Büttiker

Medium and high energy absorptive parts contribute to dispersive expressions for D- wave scattering lengths, $a^0_2$ and $a^2_2$. For the model employed by Basdevant, Frogatt and Peterson we find the D- wave driving term contributions to the D- wave scattering lengths are $1.8\cdot 10^{-4}$ to $a^0_2$ and $0.4\cdot 10^{-4}$ to $a^2_2$, roughly $10\%$ and $30

K. Golec--Biernat

The first measurement of diffractive processes in deep inelastic scattering at the HERA collider is analysed in terms of a &#34;soft&#34; pomeron exchange model. The partonic structure of the pomeron which emerges in this picture is determined using the QCD parton model. The important role of the gluonic component in the partonic interpretation of the data i

István Montvay

Violations of universality of couplings in a vectorlike extension of the standard model with three heavy mirror fermion families are considered. The recently observed discrepancies between experiments and the standard model in the hadronic branching fractions $R_b$ and $R_c$ of the Z-boson are explained by the mixing of fermions with their mirror fermion par

M. R. Ahmady, V. Elias, A. H. Fariborz, R. R. Mendel

We examine the heavy-quark-induced Yukawa interaction between light quarks and a light Higgs field, which is facilitated in the chiral limit by the dynamical mass of light quarks anticipated from the chiral-noninvariance of the QCD vacuum. A low-energy estimate of the strong coupling near unity can be obtained from a comparison of the explicit perturbative c

I. B. Khriplovich

At natural values of parameters of the model dicussed, the contribution of the chromoelectric dipole moment of the s-quark to the neutron electric dipole moment (EDM) exceeds considerably the experimental upper limit for the neutron EDM. As strict bounds on the parameters of the model are derived from the atomic experiment with odd isotope of mercury.

I. B. Khriplovich, K. N. Zyablyuk

We calculate the chromoelectric dipole moment (CEDM) of d- and s-quark in the supersymmetric SO(10) model. CEDM is more efficient than quark electric dipole moment (EDM), in inducing the neutron EDM. New, strict constraints on parameters of the supersymmetric SO(10) model follow in this way from the neutron dipole moment experiments. As strict bounds are der

Ian Hinchliffe, Axel Kwiatkowski

This review article discusses the experimental and theoretical status of various Parton Model sum rules. The basis of the sum rules in perturbative QCD is discussed. Their use in extracting the value of the strong coupling constant is evaluated and the failure of the naive version of some of these rules is assessed.

Julio C. Fabris, Joel Tossa

The non-minimal coupling of gravity to a scalar field can be transformed into a minimal coupling through a conformal transformation. We show how to connect the results of a perturbation calculation, performed around a Friedmann-Robertson-Walker background solution, before and after the conformal transformation. We work in the synchronous gauge, but we discus

Stefan Aminneborg, Ingemar Bengtsson, Soren Holst, Peter Peldan

It is known from the work of Banados et al. that a space-time with event horizons (much like the Schwarzschild black hole) can be obtained from 2+1 dimensional anti-de Sitter space through a suitable identification of points. We point out that this can be done in 3+1 dimensions as well. In this way we obtain black holes with event horizons that are tori or R

Daniel Dominguez

We study the dynamics of Josephson junction arrays with positional disorder and driven by an external current. We consider weak magnetic fields, corresponding to a frustration $f=n+1/25$ with $n$ integer. We find that above the critical current $i_c$ there is a plastic flow of vortices, where most of the vortices are pinned and only a few vortices flow throu

D. Carpentier, P. Le Doussal, T. Giamarchi

We study the stability of the dislocation-free Bragg glass phase in a layered geometry consisting of coupled parallel planes of d=1+1 vortex lines lying within each plane, in the presence of impurity disorder. Using renormalization group, replica variational calculations and physical arguments we show that at temperatures $T<T_G$ the 3D Bragg glass phase is

F. Ghaboussi

We discuss the relation between the Quantum Hall behaviour of charged carriers and their chaotic motion in phase space. It is shown that the quantum Hall diagram is comparable with the stepped diagram in phase space of a chaotic motion.

W. T. Gozdz, R. Holyst

In this paper we present the novel method for the generation of periodic embedded surfaces of nonpositive Gaussian curvature. The structures are related to the local minima of the scalar order parameter Landau-Ginzburg hamiltonan for microemulsions. The method is used to generate six unknown surfaces of Ia$\bar 3$d symmetry (gyroid) of genus 21, 53, 69, 109,

K. Stokbro K. W. Jacobsen, J. K. Nørskov, D. M. Deaven, C. Z. Wang

We present molecular-dynamics simulations of the Si(100) surface in the temperature range 1100-1750K. To describe the total energy and forces we use the Effective-Medium Tight-Binding model. The defect-free surface is found to melt at the bulk melting point, which we determine to be 1650 K, but for a surface with dimer vacancies we find a pre-melting of the

Kurt Stokbro

A variant of the Vanderbilt ultrasoft pseudopotential scheme, where the normconservation is released for only one or a few angular channels, is presented. Within this scheme some difficulties of the truly ultrasoft pseudopotentials are overcome without sacrificing the pseudopotential softness. i) Ghost states are easily avoided without including semicore she

E. Demircan, P. Ao, Q. Niu

Vortex dynamics in superfluids is investigated in the framework of the nonlinear Schrödinger equation. The natural motion of the vortex is of cyclotron type, whose frequency is found to be on the order of phonon velocity divided by the coherence length, and may be heavily damped due to phonon radiation. Trapping foreign particles into the vortex core can red

Darren J Wilkinson

This paper exhibits quadratic products of linear combinations of observables which identify the covariance structure underlying the univariate locally linear time series dynamic linear model. The first- and second-order moments for the joint distribution over these observables are given, allowing Bayes linear learning for the underlying covariance structure

D. Minniti, M. V. Alonso, P. Goudfrooij, P. Jablonka

We have identified 26 new globular cluster candidates in the inner 3 kpc of NGC 5128 (Cen A), the nearest known large galaxy being the probable product of a merger. The clusters are selected on the basis of their structural parameters (observed core diameters and ellipticities), as measured from archival WFPC HST images. IR photometry obtained with IRAC2B at

D. C. Heggie, P. Hut, S. L. W. McMillan

We present the first comprehensive fitting formula for exchange reactions of arbitrary mass ratios. In a comparison with numerical results, this expression is shown to be accurate in the hard binary limit to within 25\% for most mass ratios. The result will be useful in forming quantitative estimates for the branching ratios of various exchange reactions in

Stephen L. W. McMillan, Piet Hut

Scattering encounters between binaries and single stars play a central role in determining the dynamical evolution of a star cluster. In addition, three-body scattering can give rise to many interesting exceptional objects: merging can produce blue stragglers; exchange can produce binaries containing millisecond pulsars in environments quite different from t

Andrew Gould

Traditional approaches to measuring the stellar mass function (MF) are fundamentally limited because objects are detected based on their luminosity, not their mass. These methods are thereby restricted to luminous and relatively nearby stellar populations. Gravitational microlensing promises to revolutionize our understanding of the MF. It is already technol

Dan Maoz, Aaron J. Barth, Amiel Sternberg, Alexei V. Filippenko

We present UV (2300 Ang) images, obtained with the HST Faint Object Camera, of the central 20&#39;&#39; of five galaxies containing circumnuclear star-forming rings. The five galaxies are from a well-defined sample of 103 normal, nearby galaxies we have observed with HST. At the HST resolution (0.05&#39;&#39;), the rings break up into discrete star-forming c

Bohdan Paczynski

The status of searches for gravitational microlensing events of the stars in our galaxy and in other galaxies of the Local Group, the interpretation of the results, some theory, and prospects for the future are reviewed. The searches have already unveiled about 100 events, at least two of them caused by binaries, and have already proven to be useful for stud

Roelof S. de Jong

The stellar and dust content of spiral galaxies as function of radius has been investigated using near-infrared and optical broadband surface photometry of 86 face-on spiral galaxies. Colors of galaxies correlate with the azimuthally averaged local surface brightness both within and among galaxies, with the lower surface brightness regions being bluer. The c

Arnon Dar, Giora Shaviv

An improved standard solar model has been used to calculate the fluxes of standard solar neutrinos. It includes premain sequence evolution, element diffusion, partial ionization effects, and all the possible nuclear reactions between the main elements. It uses updated values for the initial solar element abundances, the solar age, the solar luminosity, the n

H. C. Ferguson, T. M. Brown, A. F. Davidsen

Much of the far-UV emission from elliptical galaxies is thought to arise from extreme horizontal branch stars and related objects. Only about 10% of the stellar population needs to evolve through this phase even in galaxies with the strongest UV upturn. However it is not yet clear if this population represents the extreme low-metallicity or high-metallicty t

Pierre Parent

We give an effective form of the theorem of Mazur-Kamienny-Merel on the torsion of elliptic curves over number fields.

Emilia Mezzetti, Dario Portelli

A classification theorem is given of smooth threefolds of $\Bbb P^5$ covered by a family of dimension at least three of plane integral curves of degree $d\geq 2.$ It is shown that for such a threefold $X$ there are two possibilities: \item{(1)} $X$ is any threefold contained in a hyperquadric; \item{(2)} $d\leq 3$ and $X$ is either the Bordiga or the Palatin

C. M. Newman, D. L. Stein

We expand on why our recent results rule out the standard SK picture of realistic spin glasses.

Glenn D. Starkman, Tanmay Vachaspati

A possible signature of a class of superconducting cosmic strings trapped in the Milky Way plasma is the emission of low energy antiprotons due to baryon number violating processes on the string. We find the terrestrial flux and the energy spectrum of such antiprotons. Current observational bounds on the flux of low energy antiprotons place a {\it lower} bou

M. Meierovich, A. Mushinski, M. P. Nightingale

Bosonic van der Waals clusters of sizes three, four and five are studied by diffusion quantum Monte-Carlo techniques. In particular we study the unbinding transition, the ultra-quantum limit where the ground state ceases to exist as a bound state. We discuss the quality of trial wave functions used in the calculations, the critical behavior in the vicinity o

Patrick J. O&#39;Donnell, Gursevil Turan

We review the present status of theoretical attempts to calculate the semileptonic charm and bottom decays and then present a calculation of these decays in the light--front frame at the kinematic point $q^2=0$. This allows us to evaluate the form factors at the same value of $q^2$, even though the allowed kinematic ranges for charm and bottom decays are ver

Bernd A. Berg

Random cost simulations were introduced as a method to investigate optimization problems in systems with conflicting constraints. Here I study the approach in connection with the training of a feed-forward multilayer perceptron, as used in high energy physics applications. It is suggested to use random cost simulations for generating a set of selected config

I. Bakas, K. Sfetsos

The Eguchi-Hanson, Taub-NUT and Atiyah-Hitchin metrics are the only complete non-singular SO(3)-invariant hyper-Kahler metrics in four dimensions. The presence of a rotational SO(2) isometry allows for their unified treatment based on solutions of the 3-dim continual Toda equation. We determine the Toda potential in each case and examine the free field reali

C. Bourrely, F. Buccella, O. Pisanti, P. Santorelli

We study the available data in polarized e-p deep inelastic scattering to test two different solutions to the so called spin crisis: one of them based on the axial gluon anomaly and consistent with the Bjorken sum rule and another one, where the defects in the spin sum rules and in the Gottfried sum rule are related. In this case a defect is also expected fo

M. Gasperini, M. Giovannini

We discuss a gauge invariant approach to the theory of cosmological perturbations in a higher-dimensonal background. We find the normal modes which diagonalize the perturbed action, for a scalar field minimally coupled to gravity, in a higher-dimensional manifold M of the Bianchi-type I, under the assumption that the translations along an isotropic spatial s

M. Boettcher, H. Mause, R. Schlickeiser

The evolution of the particle distribution functions inside a relativistic jet containing an e^-e^+ pair plasma and of the resulting $γ$-ray and X-ray spectra is investigated. The first phase of this evolution is governed by heavy radiative energy losses. For this phase, approximative expressions for the energy-loss rates due to inverse-Compton scattering, u

W. Moedritsch

A new, exactly solvable, Barbieri-Remiddi like equation for bound states of two scalar constituents interacting with massless vector particles is presented, both for stable and unstable particles. With the help of this equation the bound state spectrum is calculated to O(α^4) for a SU(N) nonabelian gauge theory. The result for the abelian case reproduces the

Anne M Green, Andrew R Liddle

We investigate, in a model-independent way, the conditions required to obtain a satisfactory model of extended inflation in which inflation is brought to an end by a first-order phase transition. The constraints are that the correct present strength of the gravitational coupling is obtained, that the present theory of gravity is satisfactorily close to gener

G. Altarelli, G. Martinelli, S. Petrarca, F. Rapuano

We argue that there is strong experimental evidence in the data of b- and c-decays that the pattern of power suppressed corrections predicted by the short distance expansion, the heavy quark effective theory and the assumption of local duality is not correct for the non-leptonic inclusive widths. The data indicate instead the presence of 1/m corrections that

Elizabeth Jenkins

The masses of baryons containing a single heavy quark are studied in a combined expansion in $1/m_Q$, $1/N_c$ and $SU(3)$ flavor symmetry breaking. Heavy quark baryon mass splittings are related to mass splittings of the octet and decuplet baryons. The $Σ_c^*$, $Ξ_c^\prime$ and $Ω_c^*$ are predicted to the level of a few MeV. A number of bottom baryon mass s

Yuri B. Suris

We demonstrate that in a certain gauge the elliptic Ruijsenaars--Schneider models admit Lax representation governed by the same dynamical $r$--matrix as their non--relativistic counterparts (Calogero--Moser models). This phenomenon was previously observed for the rational and hyperbolic models.

B. Shklyar

For linear infinite systems the approximate controllability problem by control constraints is considered. Controllability conditions represented via system parameters are obtained. Partial differential control systems and control systems with delays are considered as an example.

Christopher A. Fuchs, Carlton M. Caves

We present mathematical techniques for addressing two closely related questions in quantum communication theory. In particular, we give a statistically motivated derivation of the Bures-Uhlmann measure of distinguishability for density operators, and we present a simplified proof of the Holevo upper bound to the mutual information of quantum communication ch

Kenji Iohara

On the basis of `$RTT=TTR$&#39; formalism, we introduce the quantum double of the Yangian $Y_{\hbar}(\gtg)$ for $\gtg=\gtgl_N,\gtsl_N$ with a central extension. The Gauss decomposition of T-matrices gives us the so-called Drinfel&#39;d generators. Using these generators, we present some examples of both finite and infinite dimensional representations that ar

Kenji Iohara, Mika Kohno

A central extension of $\cD Y_{\hbar}(\gtgl_2)$ is proposed. The bosonization of level $1$ module and vertex operators are also given.

Keith A. Kearnes, Ågnes Szendrei

We clarify the relationship between the linear commutator and the ordinary commutator by showing that in any variety satisfying a nontrivial idempotent Mal&#39;cev condition the linear commutator is definable in terms of the centralizer relation. We derive from this that abelian algebras are quasi-affine in such varieties. We refine this by showing that if A

James M. Drake, Sivabal Sivaloganathan, Guiseppe Tenti

Numerous mathematical models have emerged in the medical literature over the past two decades attempting to characterize the pressure and volume dynamics the central nervous system compartment. These models have been used to study he behavior of this compartment under such pathological clinical conditions s hydrocephalus, head injury and brain edema. The num

Patrizia Rossi

Although the concept of defect of an analytic disc attached to a generic manifold of $\C^{n}$ seems to play a merely technical role, it turns out to be a rather deep and fruitful notion for the extendability of CR functions defined on the manifold. In this paper we give a new geometric description of defect, drawing attention to the behaviour of the interior

Luis Alvarez-Gaume, Jacques Distler, Costas Kounnas, Marcos Marino

We analyze the possible soft breaking of $N=2$ supersymmetric Yang-Mills theory with and without matter flavour preserving the analyticity properties of the Seiberg-Witten solution. For small supersymmetry breaking parameter with respect to the dynamical scale of the theory we obtain an exact expression for the effective potential. We describe in detail the

Nicola Maggiore, Olivier Piguet, Sylvain Wolf

We provide N=1 Super Yang-Mills theory in the Wess-Zumino gauge with mass terms for the supersymmetric partners of the gauge fields and of the matter fields, together with a supersymmetric mass term for the fermionic matter fields. All mass terms are chosen in such a way to induce soft supersymmetry breakings at most, while preserving gauge invariance to all

Fiorenzo Bastianelli, Ulf Lindstrom

We discuss an extension of the $C$-theorem to chiral theories. We show that two monotonically decreasing $C$-functions can be introduced. However, their difference is a constant of the renormalization group flow. This constant reproduces the &#39;t Hooft anomaly matching conditions.

Raju Venugopalan

At the colliders RHIC and LHC, nuclei at the ultrarelativistic energies of $100$ GeV/A and $2.7$ TeV/A will be smashed together with the hope of creating an elusive and short-lived state of matter called the quark gluon plasma. The initial conditions which determine the dynamical evolution of the quark gluon matter formed in the central region after the coll

Konstantin Selivanov

A generating function for a class of multigluon amplitudes is constructed as a particular solution of the self-duality equation.

A. Kallen

In CHPT the hadron masses obtain loop corrections from the pseudoscalar mesons which are identified with the Goldstone bosons of broken chiral symmetry. An expansion of the baryon mass in the quark masses therefore includes non-analytic terms. We calculate the nucleon mass in the one-loop approximation to order $m^4 \sim m_q^2$. We compare the result in the

S. Pastor

We show that in the presence of sufficiently strong $ν_τ$ annihilations to majorons, primordial nucleosynthesis constraints can not rule out any values of the $ν_τ$ mass up the present laboratory limit.

J. Blümlein, A. Vogt

The resummation of $O(α^{l+1} \ln^{2l} x)$ terms in the evolution kernels of non--singlet combinations of structure functions is investigated for both QED abd QCD. Numerical results are presented for unpolarized and polarized structure functions.

Remo Garattini

In the Wheeler-DeWitt framework, by a gauge fixing procedure, we set up a scheme to recover a Schrödinger type equation, living in the orbits space with the {\it lapse} function as evolution parameter. By means of the associated stationary equation, we have the possibility of calculating quantum corrections to classical quantities. The Schwarzschild wormhole

Ted Jacobson

The rank--1 sector of classical Ashtekar gravity is considered, motivated by the degeneracy of the metric along the Wilson lines in quantum loop states. It is found that the lines behave like 1+1 dimensional spacetimes with a pair of massless complex fields propagating along them. The inclusion of matter and extension to supergravity are also considered.

Alan D. Rendall

These lectures are designed to provide a general introduction to the Einstein-Vlasov system and to the global Cauchy problem for these equations. To start with some general facts are collected and a local existence theorem for the Cauchy problem stated. Next the case of spherically symmetric asymptotically flat solutions is examined in detail. The approach t

Marcelo Barreira, Mauro Carfora, Carlo Rovelli

We study quantum gravitational effects on black hole radiation, using loop quantum gravity. Bekenstein and Mukhanov have recently considered the modifications caused by quantum gravity on Hawking&#39;s thermal black-hole radiation. Using a simple ansatz for the eigenstates the area, they have obtained the intriguing result that the quantum properties of geom