May 1996 arXiv papers — page 3

Jacob D. Bekenstein

Originally regarded as forbidden, black hole ``hair'' are fields associated with a stationary black hole apart from the gravitational and electromagnetic ones. Several stable stationary black hole solutions with gauge or Skyrme field hair are known today within general relativity. We formulate here a ``no scalar--hair'' conjecture, and adduce

H. K. Janssen, K. Oerding

We investigate the density profile in a driven diffusive system caused by a plane particle source perpendicular to the driving force. Focussing on the case of critical bulk density $\bar{c}$ we use a field theoretic renormalization group approach to calculate the density $c(z)$ as a function of the distance from the particle source at first order in $ε=2-d$

S. Kobe

The Ising model is one of the standard models in statistical physics. Since 1969 more than 12000 publications appeared using this model. In 1996 Ernst Ising celebrated his 96th birthday. Some biographical notes and milestones of the development of the Ising model are given.

L. B. Ioffe, G. B. Lesovik, A. J. Millis

Fluctuations of the Hall voltage reveal information about long wavelength magnetic field fluctuations. If gauge theories of strongly correlated electrons are correct, such fluctuations are particularly large in the half-filled Landau level and in high $T_c$ superconductors. We present estimates for the magnitude, system size and frequency dependence of these

Y. Goldin, Y. Avishai

The fully nonlinear response of a many-level tunneling system to a strong alternating field of high frequency $ω$ is studied in terms of the Schwinger-Keldysh nonequilibrium Green functions. The nonlinear time dependent tunneling current $I(t)$ is calculated exactly and its resonance structure is elucidated. In particular, it is shown that under certain reas

Mark Edwards, P. A. Ruprecht, K. Burnett, R. J. Dodd

We apply linear-response analysis of the Gross-Pitaevskii equation to obtain the excitation frequencies of a Bose-Einstein condensate confined in a time-averaged orbiting potential trap. Our calculated values are in excellent agreement with those observed in a recent experiment.

Xiaowen Shan, Gary Doolen

Diffusion phenomena in a multiple component lattice Boltzmann Equation (LBE) model are discussed in detail. The mass fluxes associated with different mechanical driving forces are obtained using a Chapman-Enskog analysis. This model is found to have correct diffusion behavior and the multiple diffusion coefficients are obtained analytically. The analytical r

Srdjan Samurovic, Vladan Celebonovic

Using data on rotation curves of 134 spiral galaxies we have calculated the possible value of the tau neutrino mass. We have shown that this mass could explain the nature of the dark matter in spiral galaxies.

Lorraine A. Allen, Margaret J. Geller

We have assembled 21-cm linewidths for 376 of the 732 galaxies in a magnitude-limited redshift survey of the the Perseus-Pisces region. We analyze a distance limited subset of 271 galaxies (131 widths) to examine the relationship between linewidth and local density. The sample indicates that galaxies with linewidths $\gtrsim 480$ km/s are absent from regions

Duília F. de Mello, Leopoldo Infante, Felipe Menanteau

We have carried out an extensive survey of faint galaxies in order to examine the rise in the merger rate with redshift and to study the statistical relations between close interacting galaxies and the field galaxy population. In this paper we present the catalogs of faint pairs and groups of galaxies of 46 equatorial fields taken with the CTIO 4m prime focu

Andrew A de Laix, Tanmay Vachaspati

We calculate the deflection of a light ray caused by the gravitational field of a cosmic string loop in the weak field limit and reduce the problem to a single quadrature over a time slice of the loop's world sheet. We then apply this formalism to the problem of gravitational lensing by cosmic string loops. In particular, we find an analytic solution for

Dan Maoz, Alexei V. Filippenko, Luis C. Ho, F. Duccio Macchetto

We present an atlas of UV ($\sim 2300$ \AA) images, obtained with the Hubble Space Telescope (HST) Faint Object Camera, of the central $22''\times 22''$ of 110 galaxies. The observed galaxies are an unbiased selection constituting about one half of a complete sample of all large ($D>6'$) and nearby ($V< 2000$ km s$^{-1}$) galaxies. This is the first extensiv

J. C. Niemeyer, W. Hillebrandt, S. E. Woosley

A series of two dimensional numerical simulations of explosive nuclear burning is presented for white dwarfs near the Chandraskhar mass. We assume that the burning begins as a slow deflagration front at or near the center of the star, and continues until the density in the burning regions has declined to about 10$^7$ g cm$^{-3}$, where the flame is essential

D. Fargion, A. Salis

We considered the Inverse Compton Scattering (ICS) of charged particles onto photons whose distribution is a Black Body Radiation (BBR) deriving the exact energy and angular differential distribution in the general case and in its most useful expansions. These results can be successfully applied in high energy accelerators experiments to evaluate the ICS con

D. Fargion, A. Salis

Inverse Compton Scattering (ICS) by a relativistic electron beam jet at GeV energies (emitted by a compact object as a NS, BH,...), a NSJ, onto thermal BBR photons (from a nearby stellar companion) may originate a collinear gamma jet (GJ). Due to the binary system interaction the GJ precession would blaze suddenly toward the observer leading to a GRB event.

Piotr Pragacz

The goal of the paper is two-fold. At first, we attempt to give a survey of some recent applications of symmetric polynomials and divided differences to intersection theory. We discuss: polynomials universally supported on degeneracy loci; some explicit formulas for the Chern and Segre classes of Schur bundles with applications to enumerative geometry; flag

Jorma Louko, Jarmo Makela

We consider a Hamiltonian theory of spherically symmetric vacuum Einstein gravity under Kruskal-like boundary conditions in variables associated with the Einstein-Rosen wormhole throat. The configuration variable in the reduced classical theory is the radius of the throat, in a foliation that is frozen at the left hand side infinity but asymptotically Minkow

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

We calculate the supersymmetric QCD corrections in order $α_s$ to the decays $\squark_i \to q&#39; \chargino_j$ (i,j = 1,2) and $\squark_i \to q \neutralino_k$ (k = 1,...4) within the Minimal Supersymmetric Standard Model. In particular we consider the decays of squarks of the third generation, $\stop_i$ and $\sbottom_i$ (i = 1,2), where the left--right mixi

J. S. Prakash

A &#39;differential measure&#39; is used to cast our calculus for the group $SU(3)$ into a form similar to Schwinger&#39;s boson operator calculus for the group $SU(2)$. It is then applied to compute (i) the inner product between the basis states and (ii) an algebraic formula for the Clebsch-Gordan coefficients. These were obtained earlier by us using Gaussi

K. S. Babu, Chris Kolda, Frank Wilczek

We calculate the low-lying spectrum of new particles expected in a minimal model wherein supersymmetry breaking at < 100 TeV is indirectly transmitted to the Standard Model. We calculate the couplings of these particles relevant to their most nearly accessible experimental signatures, and estimate those signatures quantitatively. Running of various couplings

A. A. Andrianov, M. V. Ioffe, D. N. Nishnianidze

The new method based on the SUSY algebra with supercharges of higher order in derivatives is proposed to search for dynamical symmetry operators in 2-dim quantum and classical systems. These symmetry operators arise when closing the SUSY algebra for a wide set of potentials. In some cases they are of 2-nd order in derivatives. The particular solutions are ob

S. Trentalange, S. U. Pandey

Sonoluminescence may be studied in detail by intensity correlations among the emitted photons. As an example, we discuss an experiment to measure the size of the light-emitting region by the Hanbury Brown-Twiss effect. We show that single bubble sonoluminescence is almost ideally suited for study by this method and that plausible values for the physical para

H. Kouno, T. Mitsumori, Y. Iwasaki, K. Sakamoto

The properties of nuclear matter are studied in the cut-off field theory. It is found that, under the Hartree approximation, the small cut-off makes the equations of state hard, especially at higher densities. The theory is modified in the framework of the renormalization group methods with arbitrary cut-off $Λ^\prime$. It is found that the expansion in term

Sandro S. Costa, George E. A. Matsas

Park et al&#39;s recent comment (hep-th/9605132) that for detectors with large energy gap in comparison with the temperature of the background thermal bath, the maximum excitation rate is obtained for some non-zero detector&#39;s velocity is correct but was previously discussed by ourselves elsewhere, and moreover does not affect in our paper above any mathe

Wolf-Dieter Nowak

The physics scope of a possible future experiment utilizing an internal polarized nucleon target in the HERA proton beam is discussed. By measuring single spin asymmetries in inclusive particle production at 820~GeV beam energy the higher-twist sector of perturbative QCD can be probed with good statistical sensitivity. To support the physics case for proton

T. Mizoguchi, M. Biyajima, I. V. Andreev, G. Wilk

We propose a new method for the Coulomb wave function correction including the momentum resolution for charged hadron pairs and apply it to the precise data on $π^+π^-$ correlations obtained in $p + \mbox{Ta}$ reaction at 70 GeV/c. It is found that interaction regions of this reaction (assuming Gaussian source function) are $5.6 \pm 3.0$ and $4.4 \pm 2.6$ fm

Brett van de Sande

I discuss the slow convergence of Discretized Light Cone Quantization (DLCQ) in the small mass limit and suggest a solution.

Dilip Kumar Ghosh, Rohini M. Godbole, Biswarup Mukhopadhyaya

We have made a detailed study of the signals produced at LEP-2 from charged scalar bosons whose dominant decay channels are into four fermions. The event rates as well as kinematics of the final states are discussed when such scalars are either pair-produced or are generated through a tree-level interaction involving a charged scalar, the W and the Z. The ba

M. Göckeler, R. Horsley, V. Linke, P. Rakow

We perform a high statistics calculation of the equation of state for non-compact QED on large lattices. The calculation extends to fermionic correlation lengths of $\approx 8$, and it is combined with a finite size scaling analysis of the lattice data.

Shuhei Mano, Hisao Suzuki, Eiichi Takasugi

Analytic solutions of the Regge-Wheeler equation are presented in the form of series of hypergeometric functions and Coulomb wave functions which have different regions of convergence. Relations between these solutions are established. The series solutions are given as the Post-Minkowskian expansion with respect to a parameter $ε\equiv 2Mω$, $M$ being the ma

Man Chun Leung

We study a second order differential equation corresponding to rotationally symmetric $F$-harmonic maps between certain noncompact manifolds. We show unique continuation and Liouville&#39;s type theorems for positive solutions. Asymptotic properties and the existence of bounded positive solutions are investigated.

C. Rascon, L. Mederos, G. Navascues

A new approach to the averaged two-particle distribution function of a crystalline phase is presented. It includes an indirect check of the merit of the Gaussian approximation for the local density and a new way to inferring values of the thermodynamic variables from simulation data. The equation of state and the compressibility of the hard-sphere FCC crysta

S. Das Sarma, E. H. Hwang, Lian Zheng

We develop the plasmon-pole approximation for an interacting electron gas confined in a semiconductor quantum wire. We argue that the plasmon-pole approximation becomes a more accurate approach in quantum wire systems than in higher dimensional systems because of severe phase-space restrictions on particle-hole excitations in one dimension. As examples, we u

J. F. F. Mendes, R. Dickman, H. Herrmann

We study critical spreading in a surface-modified directed percolation model in which the left- and right-most sites have different occupation probabilities than in the bulk. As we vary the probability for growth at an edge, the critical exponents switch from the compact directed percolation class to ordinary directed percolation. We conclude that the nonuni

Y. Naveh, B. Laikhtman

We present an InAs-GaSb-based system in which the electric-field tunability of its 2D energy gap implies a transition towards a thermodynamically stable excitonic condensed phase. Detailed calculations show a 3 meV BCS-like gap appearing in a second-order phase transition with electric field. We find this transition to be very sharp, solely due to exchange i

Ramon Aguado, Gloria Platero

We analyze the I-V characteristic of a double quantum well integrated in an antenna and driven by THz radiation.We propose a microscopic model to calculate the sequential current including selfconsistently the Coulomb interaction in a mean field approximation.Additional features in the current appear which depend not only on the frequency and intensity of th

W. Stephan, M. Capone, M. Grilli, C. Castellani

We investigate the influence of electron-phonon coupling on the superexchange interaction of magnetic insulators. Both the Holstein-Hubbard model where the phonons couple to the electron density, as well as an extended Su, Schrieffer, Heeger model where the coupling arises from modulation of the overlap integral are studied using exact diagonalization and pe

Jiunn-Ren Roan, E. I. Shakhnovich

The dynamics of a heteropolymer chain in solution is studied in the limit of long chain length. Using functional integral representation we derive an effective equation of motion, in which the heterogeneity of the chain manifests itself as a time-dependent excluded volume effect. At the mean field level, the heteropolymer chain is therefore dynamically equiv

Owen Rambow, Giorgio Satta

In synchronous rewriting, the productions of two rewriting systems are paired and applied synchronously in the derivation of a pair of strings. We present a new synchronous rewriting system and argue that it can handle certain phenomena that are not covered by existing synchronous systems. We also prove some interesting formal/computational properties of our

Heino Falcke, William Sherwood, Alok Patnaik

We have performed quasi-simultaneous radio flux density measurements at 2.7 and 10 GHz for all PG quasars with radio flux densities between 4-200 mJy. We find that a large fraction of these sources are variable, flat-spectrum quasars. This brings the total fraction of flat-spectrum quasars with a ratio between radio and optical flux of R>10 - a value previou

P. Haensel

Contents: 1.Introduction 2. Formation and composition of the solid crust 3. The bottom layers of the crust: exotic nuclear shapes and topologies 4. Crust contribution to stellar mass and moment of inertia 5. Solid cores 6. Deformation, elastic strain and mountains 7. Shape and energy of rotating, partially solid neutron star 8. Oblateness and precession 9. G

Beverley J. Wills

Here we speculate on what observations are telling us about the difference between radio-loud and radio-quiet QSOs. The observations are (i) the relation between ultraviolet-optical luminosity and `jet power&#39;, (ii) the dependences of emission and absorption line spectra, and the spectral energy distribution, on radio core-dominance, assumed to be an indi

K. Z. Stanek, A. Udalski, M. Szymanski, J. Kaluzny

The color-magnitude diagrams of $\sim 7 \times 10^5$ stars obtained for 12 fields across the Galactic bulge with the OGLE project reveal a well-defined population of bulge red clump giants. We find that the distributions of the apparent magnitudes of the red clump stars are systematically fainter when moving towards lower galactic $l$ fields. The most plausi

Beverley J. Wills, M. S. Brotherton

QSOs&#39; emission lines arise from highest velocity (approximately 10000 km/s), dense gas within approximately 0.1 parsec of the central engine, out to low-velocity, low-density gas at great distances from the host galaxy. In radio-loud QSOs there are clear indications that the distribution and kinematics of emission-line gas are related to the symmetry axi

Ming Lu, Michael Luke, Martin J. Savage, Brian H. Smith

We calculate the ${\cal O}(α_s^2 β_0 )$ corrections to the decay rate $b\rightarrow c\bar c s$. For reasonable values of $m_c/m_b$ this term is of the same order as both the one-loop and $\CO(α_s^2 \log^2 m_W/m_b)$ corrections to the decay rate. For $m_c/m_b=0.3$ the $\CO(α_s^2β_0)$ corrections enhance the rate by $\sim 18\%$ . We also discuss the $\CO(α_s^2

Matthias Heyssler

Recent measurements of the single inclusive jet cross section at the Tevatron by the CDF Collaboration maybe suggest a modified picture of QCD in the large $E_T$ range. One possible explanation of the measured jet excess is the introduction of a neutral heavy vector boson $Z&#39;$. A parameter fit of this new model to the CDF data, in leading order perturbat

A. D. Jackson, M. K. Şener, J. J. M. Verbaarschot

We find the finite volume QCD partition function for arbitrary quark masses. This is a generalization of a result obtained by Leutwyler and Smilga for equal quark masses. Our result is derived in the sector of zero topological charge using a generalization of the Itzykson-Zuber integral appropriate for arbitrary complex matrices. We present a conjecture rega

James N. Labrenz, Stephen R. Sharpe

We develop chiral perturbation theory for baryons in quenched QCD. Quenching (the elimination of diagrams containing virtual quark loops) is achieved by extending the Lagrangian method of Bernard and Golterman, and is implemented in a theory where baryons are treated as fixed velocity sources. Our method requires that the octet baryons be represented by a th

K. Oerding

Using field-theoretic renormalization group methods the long-time behaviour of the A+B -> 0 annihilation reaction with equal initial densities n_A(0) = n_B(0) = n_0 in a quenched random velocity field is studied. At every point (x, y) of a d-dimensional system the velocity v is parallel or antiparallel to the x-axis and depends on the coordinates perpendicul

A. G. Pronko

We consider bosonisation of the low-energy QCD based on integrating the anomaly of the extended chiral (E$χ$) transformation which depends both on pseudoscalar meson and scalar diquark fields as parameters. The relationship between extended chiral and usual chiral anomalies and related anomalous actions is studied. The effective action for the extended chira

B. Alles, D. S. Henty, H. Panagopoulos, C. Parrinello

We compute the running QCD coupling on the lattice by evaluating two-point and three-point off-shell gluon Green&#39;s functions in a fixed gauge and imposing non-perturbative renormalisation conditions on them. Our exploratory study is performed in the quenched approximation at beta=6.0 on 16^4 and 24^4 lattices. We show that, for momenta in the range 1.8-2

Alexei Anselm, Zurab Berezhiani

In an analogy to the case of axion, which converts the $Θ$-angle into a dynamical degree of freedom, we are trying to imagine a situation where the quark mixing angles turn out to be dynamical degrees of freedom (pseudo-Goldstone bosons), and their vacuum expectation values are obtained from the minimization of the vacuum energy. We present an explicit super

S. Ambrosanio, G. L. Kane, Graham D. Kribs, Stephen P. Martin

We analyze the prospects for discovering supersymmetry at the Fermilab Tevatron and CERN LEP colliders in the scenario that the lightest supersymmetric particle is a gravitino of mass < 1 keV. We consider in particular the case that the lightest neutralino has a nearly 100% branching fraction into gravitino + photon within the detector. This implies that sup

L. D. Faddeev

I study the technique of Algebraic Bethe Ansatz for solving integrable models and show how it works in detail on the simplest example of spin 1/2 XXX magnetic chain. Several other models are treated more superficially, only the specific details are given. Several parameters, appearing in these generalizations: spin $s$, anisotropy parameter $\ga$, shift $\om

S. L. Lyakhovich, A. A. Sharapov, K. M. Shekhter

The massive spinning particle in six-dimensional Minkowski space is described as a mechanical system with the configuration space ${\ R}% ^{5,1}\times {\ CP}^3$. The action functional of the model is unambigiously determined by the requirement of identical (off-shell) conservation for the phase-space counterparts of three Casimir operators of Poincaré group.

K. Zuber

The effect of Majorana neutrinos in the MeV mass range on the double beta decay of various isotopes is studied on pure phenomenological arguments. By using only experimental half life data, limits on the mixing parameter $U_{eh}^2$ of the order 10$^{-7}$ can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined

Vittorio Del Duca

Using the helicity formalism in the high-energy limit, we compute the amplitudes which generate the real next-to-leading-logarithmic corrections to the BFKL equation. Accordingly, we provide a list of all the off-shell vertices necessary to build such amplitudes.

J. Rathsman

We discuss how the renormalisation scheme ambiguities in QCD can be fixed, when two observables are related, by requiring the coefficients in the perturbative expansion relating the two observables to have their conformal limit values, i.e. to be independent of the $β$-function of the renormalised coupling. We show how the next-to-leading order BLM automatic

A. Widom, Y. N. Srivastava

Lowe, Bassalleck, Burkhardt, Rusek, Stephenson, and Goldman assert, under the assumption of decays at fixed space-time points, that Kaon induced Lambda oscillations disappear. We find, under the same assumption, that energy conservation and momentum conservation also disappear. Ordinary particles can exhibit quantum oscillations.

J. A. S. Lima

A new Planckian distribution for cosmologies with photon creation is derived using thermodynamics and semiclassical considerations. This spectrum is preserved during the evolution of the universe and compatible with the present spectral shape of the cosmic microwave background radiation(CMBR). Accordingly, the widely spread feeling that cosmologies with cont

J. A. S. Lima

The thermodynamic behavior of vacuum decaying cosmologies is investigated within a manifestly covariant formulation. Such a process corresponds to a continuous irreversible energy flow from the vacuum component to the created matter constituents. It is shown that if the specific entropy per particle remains constant during the process, the equilibrium relati

Georges Bouzerar, G. I. Japaridze

Using exact Lanczos diagonalizations we have shown that the pair-hopping model for {\it negative} $W$ exhibits a phase transition into $η$-{\it superconducting state}. The transition occurs at {\it any band filling} and the critical value $W_{c}$ varies between $W_{c} \simeq -1.75t$ at half-filling to $W_{c} \simeq -2t$ for two particles on the lattice.

Beverley J. Wills

In the first of a series of three lectures we discuss ways of measuring the power available to feed the jets in powerful FR II radio sources. For unobscured radio-loud QSOs we present evidence that this power is directly related to the UV-optical luminosity, or probably more accurately, to the power radiated through processes of accretion in a strong gravita

Gordon Chalmers

The moduli space describing the low-energy dynamics of BPS multi-monopoles for several charge configurations is presented. We first prove the conjectured form of the moduli space of $n-1$ distinct monopoles in a spontaneously broken SU(n) gauge theory. We further propose the solution where one of the charge components has two units, hence asymptotically corr

V. A. Slobodenyuk

With a help of the Schwinger --- DeWitt expansion analytical properties of the evolution operator kernel for the Schrödinger equation in time variable $t$ are studied for the Coulomb and Coulomb-like (which behaves themselves as $1/|\vec q|$ when $|\vec q| \to 0$) potentials. It turned out to be that the Schwinger --- DeWitt expansion for them is divergent.

Yoshiyuki Watabiki

We show that universal functions play an important role in the observation of the fractal structure of space--time in the numerical simulation of quantum gravity.

Micha Berkooz, Robert G. Leigh, Joseph Polchinski, John H. Schwarz

We consider various aspects of compactifications of the Type I/heterotic $Spin(32)/\Z_2$ theory on K3. One family of such compactifications includes the standard embedding of the spin connection in the gauge group, and is on the same moduli space as the compactification of the heterotic $E_8\times E_8$ theory on K3 with instanton numbers (8,16). Another clas

A. Abd El-Hady, Alakabha Datta, K. S. Gupta, J. P. Vary

We calculate the form factors for the semileptonic decays of the $B$ meson to $D$ and $D^*$ mesons in a Bethe-Salpeter model. We show that our model is consistent with the constraints of Heavy Quark Effective Theory (HQET) and we extract the matrix elements that represent the $1/m_Q$ corrections to the form factors in HQET. With available data, we obtain $V_

J. F. Gunion

Future muon colliders will have remarkable capability for revealing and studying physics beyond the Standard Model. A first muon collider with variable c.m.\ energy in the range $\sqrt s = 100$ to 500~GeV provides unique opportunities for discovery and factory-like production of Higgs bosons in the $s$-channel. For excellent (but achievable) machine energy r

L. Giusti

We propose a method which allows the generalization of the Landau lattice gauge-fixing procedure to generic covariant gauges. We report preliminary numerical results showing how the procedure works for $SU(2)$ and $SU(3)$. We also report numerical results showing that the contribution of finite lattice-spacing effects and/or spurious copies are relevant in t

E. Ellingson, H. K. C. Yee, J. Bechtold, R. Elston

The spectral energy distribution of the proto-galaxy candidate MS1512-cB58 at $z =2.72$ discovered by Yee et al. (1996) is presented. Photometry in seven bands ranging from $g$ to $K$$&#39;$ (1300--6000 Å~rest wavelength) are fitted with population synthesis models from Bruzual \& Charlot (1993). The data confirm a very young age for this galaxy, in agreemen

Guenter Sigl, David N. Schramm, Sangjin Lee, Paolo Coppi

Very recently, a possible clustering of a subset of observed ultrahigh energy cosmic rays above about 40EeV (4x10^19eV) in pairs near the supergalactic plane was reported. We show that a confirmation of this effect would provide information on origin and nature of these events and, in case of charged primaries, imply interesting constraints on the extragalac

F. Ciacio, S. Degl&#39;Innocenti, B. Ricci

We present an updated version of our standard solar model (SSM) where helium and heavy elements diffusion is included and the improved OPAL equation of state (Rogers 1994, Rogers Swenson \& Iglesias 1996) is used. In such a way the EOS is consistent with the adopted opacity tables, from the same Livermore group, an occurrence which should further enhance the

Thomas J. Weiler, Thomas W. Kephart

We suggest that the highest energy $ \gsim 10^{20}$ eV cosmic ray primaries may be relativistic magnetic monopoles. Motivations for this hypothesis are twofold: (i) conventional primaries are problematic, while monopoles are naturally accelerated to $E \sim 10^{20}$ eV by galactic magnetic fields; (ii) the observed highest energy cosmic ray flux is just belo

Domingos Alves, Jose Fernando Fontanari

A population genetics formulation of Eigen&#39;s molecular quasispecies model is proposed and several simple replication landscapes are investigated analytically. Our results show a remarcable similarity to those obtained with the original kinetics formulation of the quasispecies model. However, due to the simplicity of our approach, the space of the paramet

Michael Martin Nieto

A completely analytic description is given of the motion of a trapped ion which is in either an even or an odd coherent state. Comparison to recent theoretical and experimental work is made.

K. Jedamzik

We consider the formation of horizon-size primordial black holes (PBH's) from pre-existing density fluctuations during cosmic phase transitions. It is pointed out that the formation of PBH's should be particularly efficient during the QCD epoch due to a substantial reduction of pressure forces during adiabatic collapse, or equivalently, a significant decreas

H. Montani, R. Trinchero

We carry out a generalization of quantum group co-representations in order to encode in this structure those cases where non-commutativity between endomorphism matrix entries and quantum space coordinates happens.

V. I. Belinicher, A. L. Chernyshev, V. A. Shubin

Dispersion relation for the CuO$_2$ hole is calculated basing on the {\it generalized} $t$-$t^{\prime}$-$J$ model, recently derived from the three-band one. Numerical ranges for all model parameters, $t/J=2.4..2.7$, $t^{\prime}/t = 0..-0.25$, $t^{\prime\prime}/t=0.1..0.15$, and three-site terms $2t_N\sim t_S\sim J/4$, have been strongly justified previously.

Martin Bordemann

We show that for every vector bundle E over any given symplectic manifold M there exists an explicitly given super-Poisson bracket on the space of sections of the dual Grassmann bundle associated to E built out of symplectic structure of M, a fibre metric on E, and a connection in E compatible with the given fibre metric. Moreover, we construct a deformation

C. da Providência, L. Brito, J. da Providência, M. Nielsen

Isoscalar collective modes in a relativistic meson-nucleon system are investigated in the framework of the time-dependent Thomas-Fermi method. The energies of the collective modes are determined by solving consistently the dispersion relations and the boundary conditions. The energy weighted sum rule satisfied by the model allows the identification of the gi

H. Arenhoevel

The importance of subnuclear degrees of freedom in photon absorption and electron scattering by nuclei is discussed. After a short introduction into the basic properties of one-photon processes and a very brief survey on the nuclear response in the various regions of energy and momentum transfers, the particular role of subnuclear degrees of freedom in terms

L. P. Kaptari, K. Yu. Kazakov

Influence of the nuclear binding in the deuteron deep inelastic structure function $F_2(x,Q^2)$ is investigated. The description is based on the Bethe-Salpeter formalism in the ladder approximation and the operator product expansion within an effective meson-nucleon theory. It is shown that the binding in a fully relativistic treatment can be simply parametr

H. Nakada, T. Sebe

GT transitions in $N=28\sim 30$ nuclei are studied in terms of a large-scale realistic shell-model calculation, by using Towner&#39;s microscopic parameters. $B({\rm GT})$ values to low-lying final states are reproduced with a reasonable accuracy. Several gross properties with respect to the GT transitions are investigated with this set of the wavefunctions

P. R. Huffman, N. R. Roberson, W. S. Wilburn, C. R. Gould

A test of parity-conserving, time-reversal non-invariance (PC TRNI) has been performed in 5.9 MeV polarized neutron transmission through nuclear spin aligned holmium. The experiment searches for the T-violating five-fold correlation via a double modulation technique - flipping the neutron spin while rotating the alignment axis of the holmium. Relative cross

Manuel Gonzalez, Joaquin M. Gutierrez

We prove a basic property of continuous multilinear mappings between topological vector spaces, from which we derive an easy proof of the fact that a multilinear mapping (and a polynomial) between topological vector spaces is weakly continuous on weakly bounded sets if and only if it is weakly {\it uniformly\/} continuous on weakly bounded sets. This result

Carl M. Bender, Luis M. A. Bettencourt

Conventional weak-coupling perturbation theory suffers from problems that arise from resonant coupling of successive orders in the perturbation series. Multiple-scale perturbation theory avoids such problems by implicitly performing an infinite reordering and resummation of the conventional perturbation series. Multiple-scale analysis provides a good descrip

C. Lopez, F. Barreiro, F. J. Yndurain

We present parametrizations for the proton structure function $F_2$ in the next to leading order in perturbative QCD. The calculations show that the dominant term to $F_2(x,Q^2)$ should grow as $x^{-\ls}$ for small $x$ values, with the exponent $\ls$ being essentially independent of $Q^2$. Comparisons with the most recent H1 and ZEUS data confirm the value $

Ralf Hempfling

We compute the dominant one-loop radiative corrections to the cross-section for $e^+ e^- \rightarrow V_1 V_2$ $(V_{1/2} = γ, Z, W^\pm$) in the MSSM. We find that the genuine vertex corrections are very small. The oblique corrections are potentially large enough to be tested at LEP-II or NLC. However, the sensitivity is below the one from other high precision

Andreas Blumhofer, Marcus Hutter

Fermion mass models usually contain a horizontal symmetry and therefore fail to predict the exponential mass spectrum of the Standard Model in a natural way. In dynamical symmetry breaking there are different concepts to introduce a fermion mass spectrum, which automatically has the desired hierarchy. In constructing a specific model we show that in some mod

J. Fleischer, V. A. Smirnov, O. V. Tarasov

A method of calculating Feynman diagrams from their small momentum expansion [1] is extended to diagrams with zero mass thresholds. We start from the asymptotic expansion in large masses [2] (applied to the case when all $M_i^2$ are large compared to all momenta squared). Using dimensional regularization, a finite result is obtained in terms of powers of log

R. Kirschner

Some results on the perturbative Regge asymptotics are reviewed. The concepts of the reggeon interaction approach and the double logarithmic approximation are outlined. Contribution to the Zeuthen Workshop on QCD and QED at higher order, Rheinsberg, April 1996.

Gian F. Giudice

Elementary introduction to physics beyond the Standard Model. Lectures delivered at the 1995 European School of High-Energy Physics in Dubna, Russia.

H. Navelet, R. Peschanski, Ch. Royon, S. Wallon

The $F_2$, $F_G$, $R = F_L/F_T$ proton structure functions are derived in the QCD dipole picture. Assuming $k_T$ and renormalization-group factorization, we relate deep-inelastic proton scattering to deep-inelastic onium scattering. We get a three-parameter fit of the 1994 H1 data in the low-$x,$ moderate $Q^2$ range. The ratios $F_G/F_2$ and $R$ are predict

Harald Fritzsch

A simple breaking of the subnuclear democracy among the quarks leads to a mixing between the second and the third family, in agreement with observation. Introducing the mixing between the first and the second family, one finds an interesting pattern of maximal CP-violation as well as a complete determination of the elements of the CKM matrix and of the unita

J. M. Moreno, D. H. Oaknin, M. Quiros

We construct the sphaleron solution, at zero and finite temperature, in the Minimal Supersymmetric Standard Model as a function of the supersymmetric parameters, including the leading one-loop corrections to the effective potential in the presence of the sphaleron. At zero temperature we have included the one-loop radiative corrections, dominated by the top/

N. G. Deshpande, B. Dutta, E. Keith

We show that an intermediate gauge symmetry breaking scale can be a significant source of electric dipole moments for the electron and neutron in supersymmetric grand unified theories. New phases, similar to that of the CKM matrix, appear which do not arise from the supersymmetry (SUSY) breaking operators. To illustrate, we choose some grand unified SUSY mod

F. Karsch, M. Lütgemeier, A. Patkós, J. Rank

The non-perturbative input necessary for the determination of the ${\cal O}(g^6)$ part of the weak coupling expansion of the free energy density for SU(2) and SU(3) gauge theories is estimated. Although the perturbative information completing the contribution to this order is missing, we give arguments that the magnetic fluctuations are dominated by screened

Y. Iwasaki, K. Kanaya, S. Kaya, S. Sakai

The nature of finite temperature transitions in lattice QCD with Wilson quarks is studied near the chiral limit for the cases of 2, 3, and 6 flavors of degenerate quarks ($N_F=2$, 3, and 6) and also for the case of massless up and down quarks and a light strange quark ($N_F=2+1$). Our simulations mainly performed on lattices with the temporal direction exten

J. D. Finley, III, J. F. Plebański, Maciej Przanowski

In 1993, a proof was published, within ``Classical and Quantum Gravity,&#39;&#39; that there are no regular solutions to the {\it linearized} version of the twisting, type-N, vacuum solutions of the Einstein field equations. While this proof is certainly correct, we show that the conclusions drawn from that fact were unwarranted, namely that this irregularit