October 1997 arXiv papers — page 7

A. Djouadi

I discuss the effects of QCD radiative corrections in Supersymmetric theories. After summarizing the SUSY--QCD lagrangian in the Minimal Supersymmetric extension of the Standard Model, I will discuss the new features introduced by SUSY, and the main complications compared to standard QCD corrections. I will then discuss a few examples of QCD calculations in

A. Djouadi

I briefly review the Higgs sector in the Standard Model. After summarizing the properties of the Higgs boson, I will discuss the prospects for discovering this particle at the present colliders LEP2 and Tevatron and at the next generation colliders LHC and a high-energy $e^+e^-$ linear collider. The possibilities of studying the properties of the Higgs parti

A. Djouadi, P. Gambino, S. Heinemeyer, W. Hollik

In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for the gluon-exchange contribution. The complete analytic result for the gluino-exchange contribution is very lengthy; we

Stephen G. Naculich

Just as fermion zero modes can alter the degeneracy and quantum numbers of a soliton, fermion energies can affect the form and stability of a nontopological soliton. We discuss the kink in a two-dimensional linear sigma model, and show that, when coupled to fermions, the kink is no longer an extremum of the energy functional. The kink in this model possesses

T. Nishikawa, S. Saito, Y. Kondo

We investigate the electric polarizabilities of neutral baryons using the method of QCD sum rules. The diagrams in the operator product expansion are taken into account up to dimension 6. We obtain different values of the polarizabilities among hyperons, the ordering of which is given $\barα_n>\barα_{Ξ^0}>\barα_Λ$. The polarizability of ${Σ^0}$, $\barα_{Σ^0}

G. Altarelli

Talk given at the XVIII International Symposium on Lepton-Photon Interactions, Hamburg, 1997. 1. Introduction 2. Status of the Data 3. Precision Electroweak Data and the Standard Model 4. A More General Analysis of Electroweak Data 5. The Case for Physics beyond the Standard Model 6. The Search for the Higgs 7. New Physics at HERA? 8. Conclusion

Ya. I. Azimov, R. M. Ryndin

The Aharonov-Casher (AC) effect for quantum motion of a neutral magnetized particle in the electric field is believed to be a topological effect closely related to the known Aharonov-Bohm (AB) effect. We study how it depends on the spin of the particle involved. Duality of the AB and AC effects is demonstrated to exist only for two extreme spin (and magnetic

V. V. Kiselev

The fragmentation function of a scalar leptoquark into possible S-wave bound states with a heavy anti-quark is calculated to the leading order in perturbative QCD for the high energy processes at large transverse momenta. The one-loop equations for the $q^2$-evolution of moments of the fragmentation function due to the hard gluon emission by the leptoquark a

Véronique Bernard

Photoproduction of neutral and charged pions off nucleons and deuterium has been precisely calculated in baryon chiral perturbation theory. I review the predictions with the accurate data that have become available over the last few years. Some progress in the description of neutral pion electroproduction off protons is also discussed.

A. V. Berezhnoy, V. V. Kiselev, A. K. Likhoded

Calculations of cross-sections for the gluon-photon production of $B_c$ and $B_c^*$ mesons as well as for the production in $ep$-interactions at HERA are performed in the leading order of perturbative QCD. We show that the nonabelian structure of QCD leads to an essential forward-backward asymmetry in these processes.

Thomas DeGrand, Anna Hasenfratz, Tamas G. Kovacs

We describe quenched spectroscopy in SU(2) gauge theory using smoothed gauge field configurations. We investigate the properties of quarks moving in instanton background field configurations, where the sizes and locations of the instantons are taken from simulations of the full gauge theory. By themselves, these multi-instanton configurations do not confine

S. Bilke, Z. Burda, A. Krzywicki, B. Petersson

The effect of coupling non-compact $U(1)$ gauge fields to four dimensional simplicial quantum gravity is studied using strong coupling expansions and Monte Carlo simulations. For one gauge field the back-reaction of the matter on the geometry is weak. This changes, however, as more matter fields are introduced. For more than two gauge fields the degeneracy o

K. Pinn, S. Vinti

The Svetitsky-Yaffe conjecture for finite temperature 4d SU(2) lattice gauge theory is confirmed by observing matching of block spin effective actions of the gauge model with those of the 3d Ising model. The effective action for the gauge model is defined by blocking the signs of the Polyakov loops with the majority rule. To compute it numerically, we apply

S. Guesken

We discuss latest results of lattice QCD simulations with dynamical fermions. Special emphasis is paid to the subjects of the static quark potential, the light hadron spectrum, $Υ$ spectrum, and the pion-nucleon-sigma term.

Stefano Capitani, Sergio Caracciolo, Andrea Pelissetto, Giancarlo Rossi

We apply the coordinate-space method by Luescher and Weisz to the computation of two-loop diagrams in full QCD with Wilson fermions on the lattice. The essential ingredient is the high-precision determination of mixed fermionic-bosonic propagators.

Boaz Klima

We have searched for the pair production of first generation scalar leptoquarks using the full data set (123 pb**-1) collected with the D0 detector at the Fermilab Tevatron during 1992-1996. We observe no candidates, consistent with the expected background. We combine these new results from the ee + jets and enu + jets channels with the published nunu + jets

Louis Crane

We discuss the interpretation of the state sum of Barrett and Crane.

Jochen Peitz, Stefan Appl

The equations governing dissipative relativistic hydrodynamics are formulated within the 3+1 approach for arbitrary spacetimes. Dissipation is accounted for by applying the theory of extended causal thermodynamics (Israel-Stewart theory). This description eliminates the causality violating infinite signal speeds present in the conventional Navier-Stokes equa

Frank Antonsen

We first generalise the standard Wigner function to Dirac fermions in curved spacetimes. Secondly, we turn to the Moyal quantisation of systems with constraints. Gravity is used as an example.

K. Srinivasan, L. Sriramkumar, T. Padmanabhan

In the path integral expression for a Feynman propagator of a spinless particle of mass $m$, the path integral amplitude for a path of proper length ${\cal R}(x,x'| g_{μν})$ connecting events $x$ and $x'$ in a spacetime described by the metric tensor $g_{μν}$ is $\exp-[m {\cal R}(x,x'| g_{μν})]$. In a recent paper, assuming the path integral ampl

Wlodzimierz Piechocki

Suggestions concerning the generalization of the geometric quantization to the case of nonlinear field theories are given. Results for the Liouville field theory are presented.

Mark J. Gotay, Hendrik B. Grundling

We prove that there is no faithful finite-dimensional representation by skew-hermitian matrices of a ``basic algebra of observables'' B on a noncompact symplectic manifold M. Consequently there exists no finite-dimensional quantization of any Lie subalgebra of the Poisson algebra C^\infty(M) containing B.

M. Franz, M. Ichioka

In a recent Letter Morita, Kohmoto and Maki analyzed the structure of quasiparticle states near a single vortex in a d-wave superconductor using an approximate version of the Bogoliubov - de Gennes theory. Their principal result is the existence of a bound state within the core region at finite energy with full rotational symmetry, which they assert explains

E. Granato, J. M. Kosterlitz, M. V. Simkin

A square array of Josephson junctions with modulated strength in a magnetic field with half a flux quantum per plaquette is studied by analytic arguments and dynamical simulations. The modulation is such that alternate columns of junctions are of different strength to the rest. Previous work has shown that this system undergoes an XY followed by an Ising-lik

G. M. Bruun, V. N. Nicopoulos, N. F. Johnson

We have calculated the longitudinal acoustic attenuation in a type-II superconductor in high magnetic fields within a mean-field BCS theory. We predict two new features in the corresponding attenuation signal as compared to that of the Meissner state. Our analytical calculations predict the existence of oscillations in the attenuation as the external magneti

Sadhan K. Adhikari, Angsula Ghosh

The solutions of a renormalized BCS model are studied in two space dimensions in $s$, $p$ and $d$ waves for finite-range separable potentials. The gap parameter, the critical temperature $T_c$, the coherence length $ξ$ and the jump in specific heat at $T_c$ as a function of zero-temperature condensation energy exhibit universal scalings. In the weak-coupling

C. M. Canali, W. Stephan, L. Y. Gorelik, R. I. Shekhter

We study the effect of a strong electron-electron (e-e) interaction in a system of two concentric one-dimensional rings with incommensurate areas A_1 and A_2, coupled by a tunnel amplitude. For noninteracting particles the magnetic moment (persistent current) m of the many-body ground state and first excited states is an irregular function of the external ma

R. Dum, J. I. Cirac, M. Lewenstein, P. Zoller

We propose and analyze a scheme to create dark solitons and vortices in Bose-Einstein condensates. This is achieved starting from a condensate in the internal state $|a>$ and transferring the atoms to the internal state $|b>$ via a Raman transition induced by laser light. By scanning adiabatically the Raman detuning, dark solitons and vortices are created.

T. Fujii, Y. Tsukamoto, N. Kawakami

We exactly calculate the momentum-dependent critical exponents for spectral functions in the one-dimensional anisotropic t-J models with a gap either in the spin or charge excitation spectrum. Our approach is based on the Bethe ansatz technique combined with finite-size scaling techniques in conformal field theory. It is found that the spectral functions sho

A. Jaster, H. Hahn

We present detailed Monte Carlo results for a two-dimensional grain boundary model on a lattice. The effective Hamiltonian of the system results from the microscopic interaction of grains with orientations described by spins of unit length, and leads to a nearest-neighbour interaction proportional to the absolute value of the angle between the grains. Our an

P Dalmas de Reotier, A Yaouanc

A review of the muon spin rotation and relaxation ($μ$SR) studies on magnetic materials published from July 1993 is presented. It covers the investigation of magnetic phase diagrams, of spin dynamics and the analysis of the magnetic properties of superconductors. We have chosen to focus on selected experimental works in these different topics. In addition, a

O. V. Danylenko, O. V. Dolgov, M. L. Kulic, V. Oudovenko

Impurities with the pronounced forward scattering (FS impurities) change analytical properties of the quasiparticle Green's function substantially compared to the isotropic scattering. By assuming that the superconducting pairing is due to the forward E-P scattering (FEP pairing) it is shown that the critical temperature of clean systems T_{c0} depends l

D. Feinberg, P. Germain, M. Grilli, G. Seibold

We propose a mechanism for A-type antiferromagnetism in orthorombic LaMnO_3, compatible with the large Jahn-Teller splitting inferred from structural data. Orbital ordering resulting from Jahn-Teller distortions effectively leads to A-type ordering (antiferromagnetic in the c axis and ferromagnetic in the ab plane) provided the in-plane distorsion Q_2 is lar

Michele Fabrizio, Massimo Altarelli, Maurizio Benfatto

X-ray resonant scattering at the K-edge of transition metal oxides is shown to measure the orbital order parameter, supposed to accompany magnetic ordering in some cases. Virtual transitions to the 3d-orbitals are quadrupolar in general. In cases with no inversion symmetry, such as V$_2$O$_3$, treated in detail here, a dipole component enhances the resonance

G. Mahoux, M. L. Mehta, J. -M. Normand

For the eigenvalues of $p$ complex hermitian $n\times n$ matrices coupled in a chain, we give a method of calculating the spacing functions. This is a generalization of the one matrix case which has been known for a long time.

B. Eynard, M. L. Mehta

The general correlation function for the eigenvalues of $p$ complex hermitian matrices coupled in a chain is given as a single determinant. For this we use a slight generalization of a theorem of Dyson.

T. Kuramoto

We study magnetic and critical properties of the alternating spin antiferromagnetic Heisenberg chain with $S=1/2$ and 1 in a magnetic field at T=0. The numerical diagonalization is applied to the system up to $2N=20$ sites. Checking numerically that magnetic states with the magnetization per site $m$ obey a conformal field theory with conformal anomaly $c=1$

Markus Schreier, Klaus Richter, Gert-Ludwig Ingold, Rodolfo A. Jalabert

We study the influence of a tunnel barrier on the quantum transport through a circular cavity. Our analysis in terms of classical trajectories shows that the semiclassical approaches developed for ballistic transport can be adapted to deal with the case where tunneling is present. Peaks in the Fourier transform of the energy-dependent transmission and reflec

A. Voigt, J. Richter, P. Tomczak

We investigate a frustrated Heisenberg spin-1/2 antiferromagnet on a fractal lattice of dimension d=ln3/ln2 (Sierpinski gasket). Calculations were performed using (a) exact diagonalization of all eigenstates and eigenvectors for systems up to N=15 and (b) the Decoupled-Cell Quantum-Monte-Carlo method for systems up to N=366. We present the low-lying spectrum

H. C. Lee, S. -R. Eric Yang

We have investigated chiral edges of a quantum Hall(QH) liquid at filling factor ν=2. We find that spin and charge separate in the presence of the long-range Coulomb interaction, and the tunneling density of states(DOS) is given by D(ω)\sim [-1/\lnω]^{1/2}. The measurement of the temperature and voltage dependences of the tunneling current should reveal the

F. Ghaboussi

The physical reasons in favour of a two dimensional topological model of quantum electrodynamics are discussed. It is shown that in accord with this model there is a new uncertainty relation for photon which is compatible with QED.

Barbara Di Eugenio, Johanna D. Moore, Massimo Paolucci

Our goal is to identify the features that predict the occurrence and placement of discourse cues in tutorial explanations in order to aid in the automatic generation of explanations. Previous attempts to devise rules for text generation were based on intuition or small numbers of constructed examples. We apply a machine learning program, C4.5, to induce deci

A. Mary Selvam

The author has identified quantumlike mechanics in atmospheric flows with intrinsic nonlocal space-time connections manifested as the selfsimilar fractal geometry to the global cloud cover pattern concomitant with inverse power law form for power spectra of temporal fluctuations. Such long-range spatiotemporal correlations are generic to dynamical systems in

Geza Gyuk, Gilbert P. Holder

We investigate the possibility of using globular clusters as targets for microlensing searches. Such searches will be challenging and require more powerful telescopes than now employed, but are feasible in the 0 future. Although expected event rates are low, we show that the wide variety of lines of sight to globular clusters greatly enhances the ability to

Charles F. Gammie, Kristen Menou

We show that dwarf nova disks in quiescence have rather low magnetic Reynolds number, of order 10^3. Numerical simulations of magnetized accretion disks suggest that under these conditions magnetohydrodynamic turbulence and the associated angular momentum transport is sharply reduced. This could be the physical origin of episodic accretion in dwarf nova disk

Robin Stevens, Mark Lacy, Steve Rawlings

We present preliminary results of a search for galaxies at z>4 through Lyman-limit imaging of the fields of known high-redshift radio-galaxies. Objects were selected by means of their broad-band colours, and spectroscopy of candidate objects in one of the fields has been performed through multi-slit spectroscopy at the 4.2m William Herschel Telescope. These

David Crampton, G. Gussie, A. P. Cowley, P. C. Schmidtke

Data are given for 16 extragalactic objects (predominantly AGN) behind the Magellanic Clouds and for 146 quasar candidates behind the nearby galaxies NGC 45, 185, 253, 2366, 2403 and 6822, IC 1613, M31 and M33. The Magellanic Cloud objects were identified by their X-ray emission, and precise optical and X-ray positions and optical photometry and spectra are

D. T. Frayer, E. R. Seaquist, D. A. Frail

We report the detection of 1720 and 1612 MHz OH ground-state satellite line maser regions in the starburst galaxy NGC253. We find ten compact maser features all of which are located along the narrow ridge of bright radio continuum emission within the central 10 square arcseconds of the nucleus. The compact OH features appear physically associated with region

Ata Sarajedini, Brian Chaboyer, Pierre Demarque

We present a review of the present state of knowledge regarding the relative ages of Galactic globular clusters. First, we discuss the relevant galaxy formation models and describe the detailed predictions they make with respect to the formation timescale and chemical evolution of the globular clusters. Next, the techniques used to estimate globular cluster

Ludovic Van Waerbeke

The statistical analysis of the lensing effects coupled with the statistical analysis of the number counts is a tool to probe directly the relation between the mass and the light. In particular, some properties of the bias parameter can be investigated. The correlation between the shear of a given population of galaxies, and the number counts of a different

A. Rosenberg, G. Piotto, I. Saviane, A. Aparicio

Palomar 1 is a peculiar galactic globular cluster, suspected to be younger than the bulk of the Galactic halo objects. However, such a low age can be confirmed only after a reliable determination of the metallicity. In the present paper, we use the equivalent widths (W) of the Ca II triplet on medium resolution spectra in order to determine the metal content

A. Rosenberg, I. Saviane, G. Piotto, A. Aparicio

Deep V and I CCD images of the loosely populated Galactic globular cluster Pal 1 and the surrounding field have been obtained with the INT. A color magnitude diagram down to V(lim) ~ 24, and a luminosity function complete down to V(lim) ~ 23.25 have been constructed. Adopting a reddening E(V-I)=0.20+/-0.04 and comparing the CMD of Pal 1 with 47 Tucanae, we o

B. Rudak, J. Dyks

We present a polar-cap model which incorporates a likely acceleration of Sturrock pairs with their subsequent contribution to gamma-ray luminosity L_gamma. This model reproduces L_gamma for seven pulsars detected with Compton Gamma Ray Observatory experiments, avoiding at the same time the problem of the empirical gamma-ray death line of Arons (1996). Also,

M. Lopez-Corredoira, F. Garzon, P. Hammersley, T. Mahoney

The bulge of the Galaxy is analysed by inverting K-band star counts from the Two-Micron Galactic Survey in a number of off-plane regions. A total area of about 75 square degrees of sky is analysed. Assuming a non-variable luminosity function within the bulge, we derive the top end of the K-band luminosity function and the stellar density function, whose morp

B. Rudak, J. Dyks

We present a modified scenario of gamma-ray emission from pulsars within the framework of polar cap models. Our model incorporates possible acceleration of electron-positron pairs created in magnetospheres, and their subsequent contribution to gamma-ray luminosity L_γ. It also reproduces the empirical trend in L_γfor seven pulsars detected with Compton Gamma

M. R. Merrifield

If a galaxy resides in a cluster, then its passage through the pervasive intracluster medium will produce a detectable signature in the X-ray emission from the cluster. The simplest kinematic information that can be extracted from this signature is the galaxy's direction of motion on the plane of the sky. This paper explores the constraints on cluster dy

P. Montegriffo, M. Bellazzini, F. Ferraro, A. Sarajedini

We present deep V,I CCD photometry of the globular cluster Terzan 8, recently found to be a member of the globular cluster system of the Sagittarius dwarf spheroidal galaxy. We accurately estimate the metallicity of Ter 8 and provide the first direct determination of the color excess toward this cluster. Our robust age estimate confirms that this cluster is

S. Ettori, A. C. Fabian

In this paper we discuss the effect of Coulomb collisions on the temperature profiles of the intracluster medium in clusters of galaxies, motivated by recent reports of negative temperature gradients in some clusters by Markevitch et al. The timescale for electrons and protons to reach temperature equilibrium can exceed a few billion years beyond radii of a

Andrew R Liddle, Anne M Green

We describe the changes to the standard primordial black hole constraints on density perturbations if there are modifications to the standard cosmology between the time of formation and nucleosynthesis.

Christopher J. Conselice

The structural symmetry of forty-three face-on galaxy images in the R(65 0 nm) and J(450 nm) bands are measured to determine the usefulness of symmetry a s a morphological parameter. Each galaxy image is rotated by $180$°and subtr acted from the original to obtain a quantitative value for its structural symmet ry. The symmetry numbers computed for the sample

James Murray

We numerically study the tidal instability of accretion discs in close binary systems using a two-dimensional SPH code. We find that the precession rate of tidally unstable, eccentric discs does not only depend upon the binary mass ratio q. Although the (prograde) disc precession rate increases with the strength of the tidal potential, it also increases with

James E. Rhoads, Sangeeta Malhotra

The spatial distribution of compact dark matter in our Galaxy can be determined in a few years of monitoring Galactic globular clusters for microlensing. Globular clusters are the only dense fields of stars distributed throughout the three-dimensional halo and hence are uniquely suited to probe its structure. The microlensing optical depths towards different

Mauricio Barahona, Steven H. Strogatz, Terry P. Orlando

We present analytical and numerical studies of pinned superconducting states of open-ended Josephson ladder arrays, neglecting inductances but taking edge effects into account. Treating the edge effects perturbatively, we find analytical approximations for three of these superconducting states -- the no-vortex, fully-frustrated and single-vortex states -- as

A. V. Belitsky, B. Geyer, D. Mueller, A. Schaefer

We have found the analytical solution of the LO-evolution equation for off-forward distributions which arise in the processes of deeply virtual Compton scattering or exclusive production of mesons. We present the predictions for their evolution with an input distribution taken from recent bag model calculations.

Ian Affleck

The critical behavior associated with a transverse magnetic field applied at the edge of a semi-infinite xxz S=1/2 chain is calculated using field theory techniques. Contrary to a recent claim, we find that the long-time behavior is given by a renormalization group fixed point corresponding to an infinite field which polarizes the spin at the edge. The zero

Carsten Timm, Patrik Henelius, Anders W. Sandvik, S. M. Girvin

We present 1/N Schwinger boson and quantum Monte Carlo calculations of the magnetization and NMR relaxation rate for the two-dimensional ferromagnetic Heisenberg model representing a quantum Hall system at filling factor nu=1. Comparing the analytic and numerical calculations, we find that the SU(N) version of Schwinger boson theory gives accurate results fo

Silvia Penati, Andrea Refolli, Antoine Van Proeyen, Daniela Zanon

We compute in superspace the one-loop beta-function for the nonlinear sigma-model defined in terms of the nonminimal scalar multiplet. The recently proposed quantization of this complex linear superfield, viewed as the field strength of an unconstrained gauge spinor superfield, allows to handle efficiently the infinite tower of ghosts via the Batalin-Vilkovi

C. M. Hull

Higher dimensional generalisations of self-duality conditions and of theta angle terms are analysed in Yang-Mills theories. For the theory on a torus, the torus metric and various antisymmetric tensors are viewed as coupling constants related by U-duality, arising from background expectation values of supergravity fields for D-brane or matrix theories. At ce

Shou Hua Zhu, Chong Sheng Li, Chong Shou Gao

The cross sections for the lightest neutral Higgs pair production at the one-loop level in photon-photon collisions are calculated in the Minimal Supersymmetric Standard Model(MSSM). We find that the contributions to the lightest Higgs boson pair production cross sections arising from the genuine supersymmetric virtual particles dominate over that arising fr

Konstadinos Sfetsos

We prove that a transformation, conjectured in our previous work, between phase-space variables in $\s$-models related by Poisson-Lie T-duality is indeed a canonical one. We do so by explicitly demonstrating the invariance of the classical Poisson brackets. This is the first example of a class of $\s$-models with no isometries related by canonical transforma

Glenn Barnich

Using a regularization with the properties of dimensional regularization, higher order local consistency conditions on one loop anomalies and divergent counterterms are given. They are derived without any a priori assumption on the form of the BRST cohomology and can be summarized by the statements that (i) the antibracket involving the first order divergent

M. N. Achasov, M. G. Bek, K. I. Beloborodov, A. V. Berdyugin

The paper describes experiments with the SND detector at VEPP-2M collider, carried out during the period from October 1995 until June 1997. The total integrated luminosity of 6.4 pb^{-1} was collected in the energy range 2E=0.4-1.4 GeV (MHAD97 experiment), corresponding to 4*10^5 mu^+ mu^- pairs produced. Preliminary results of the 1996 phi-meson experiment

B. Bajc, S. Fajfer, R. J. Oakes, T. N. Pham

We analyse the semileptonic decay D+ -> K- pi+ l+ nu(l) using an effective Lagrangian developed previously to describe the decays D -> P l nu(l) and D -> V l nu(l). Light vector mesons are included in the model which combines the heavy quark effective Lagrangian and chiral perturbation theory approach. The nonresonant and resonant contributions are compared.

Z. Aouissat, O. Bohr, J. Wambach.

A symmetry conserving, non-perturbative treatment based on a variational squeezed vacuum state in conjunction with a well-defined class of RPA fluctuations is applied to the SU(3) linear-sigma-model. It is shown that the Goldstone theorem holds exactly both at zero and finite temperature. The approach represents a systematic procedure which avoids problems o

N. Haba, T. Matsuoka

There are experimental indications of large flavor mixing between $ν_{μ}$ and $ν_τ$. In the unification models, in which the massless sector includes extra particles beyond the standard model, there possibly appear the mixings between quarks (leptons) and the extra particles. When large mixings occur, lepton flavor mixings can be quite different from quark f

Katsunori Kawamura

Cirelli, Manià and Pizzocchero generalized quantum mechanics by Kähler geometry. Furthermore they proved that any unital C$^{*}$-algebra is represented as a function algebra on the set of pure states with a noncommutative $*$-product as an application. The ordinary quantum mechanics is regarded as a dynamical system of the projective Hilbert space ${\cal P}(

M. Bando, T. Kugo, K. Yoshioka

We propose a simple texture for the right-handed Majorana mass matrix to give a large $ν_μ-ν_τ$ mixing angle and hierarchical left-handed neutrino mass pattern. Consistently with the Dirac mass texture of the quark sector realizing the CKM mixing, this naturally explains the recent experimental results on both the atmospheric neutrino anomaly observed by the

Q. P. Liu, Manuel Manas

The vectorial extension of the Ribaucour transformation for the Lame equations of orthogonal conjugates nets in multidimensions is given. We show that the composition of two vectorial Ribaucour transformations with appropriate transformation data is again a vectorial Ribaucour transformation, from which it follows the permutability of the vectorial Ribaucour

Luis Alberto del Pino, Hipolito Mena

The ground state energy of the quartic anharmonic oscillator is calculated by employing the Miller-Good method. For this purpose an extension of the procedure is developed, which is suitable for considering four turning points situations. A criterion for the selection of the auxiliary quantum mechanical problem is also advanced.

Goeran Faeldt, Colin Wilkin

There exists a simple relationship between a quantum-mechanical bound-state wave function and that of nearby scattering states, when the scattering energy is extrapolated to that of the bound state. This relationship is demonstrated numerically for the case of a spherical well potential and analytically for this and other soluble potentials. Provided that th

Diego A. R. Dalvit, Francisco D. Mazzitelli

In this paper we study the one dimensional dynamical Casimir effect. We consider a one dimensional cavity formed by two mirrors, one of which performs an oscillatory motion with a frequency resonant with the cavity. The naive solution, perturbative in powers of the amplitude, contains secular terms. Therefore it is valid only in the short time limit. Using a

Marc-Thierry Jaekel, Serge Reynaud

Radiation from a mirror moving in vacuum electromagnetic fields is shown to vanish in the case of a uniformly accelerated motion. Such motions are related to conformal coordinate transformations, which preserve correlation functions characteristic of vacuum fluctuations. As a result, vacuum fluctuations remain invariant under reflection upon a uniformly acce

Omar Foda, Keith S. M. Lee, Trevor A. Welsh

Using a summation formula due to Burge, and a combinatorial identity between partition pairs, we obtain an infinite tree of q-polynomial identities for the Virasoro characters χ^{p, p&#39;}_{r, s}, dependent on two finite size parameters M and N, in the cases where: (i) p and p&#39; are coprime integers that satisfy 0 < p < p&#39;. (ii) If the pair (p&#39;,

Richard Kreckel

Monte Carlo (MC) methods for numerical integration seem to be embarassingly parallel on first sight. When adaptive schemes are applied in order to enhance convergence however, the seemingly most natural way of replicating the whole job on each processor can potentially ruin the adaptive behaviour. Using the popular VEGAS-Algorithm as an example an economic m

J. Rayford Nix, Peter Moller

We have calculated the masses, deformations, and other properties of 8979 nuclei ranging from oxygen-16 to Z = 136, A = 339 and extending from the proton drip line to the neutron drip line on the basis of the 1992 version of the finite-range droplet model. The predicted quantities include the ground-state mass, deformation, microscopic correction, odd-proton

Chun Wa Wong

The production of the isoscalar Jp = 3+ didelta dibaryon d* by proton inelastic scattering from deuteron targets is described in a double-scattering Glauber approximation. Each scattering changes a target nucleon into a Delta with the help of the isovector tensor force transmitted by pi and rho mesons. The differential cross section constructed from empirica

Greg W. Anderson

We give a new method for solving a problem originally solved about 20 years ago by Sinnott and Kubert, namely that of computing the cohomology of the universal ordinary distribution with respect to the action of the two-element group generated by complex conjugation. We develop the method in sufficient generality so as to be able to calculate analogous cohom

Gerald Dunne

We review the resolvent technique for computing the effective action in planar QED. For static magnetic backgrounds the effective action yields (minus) the effective energy of the fermions, while for electric backgrounds the imaginary part of the effective action gives (half) the probability of fermion-antifermion pair creation. For some special `solitonic&#

E. Zafiris

In this paper we derive the generalisations of Gauss-Codazzi, Raychaudhuri and area change equations for classical relativistic branes and multidimensional fluids in arbitrary background manifolds with metricity and torsion. The kinematical description we develop is fully covariant and based on the use of projection tensors tilted with respect to the brane w

JM Figueroa-O&#39;Farrill

We present a novel formulation of the instanton equations in 8-dimensional Yang-Mills theory. This formulation reveals these equations as the last member of a series of gauge-theoretical equations associated with the real division algebras, including flatness in dimension 2 and (anti-)self-duality in 4. Using this formulation we prove that (in flat space) th

Meshcheryakov V. A

The S-matrix in the static limit of a dispersion relation is a matrix of a finite order N of meromorphic functions of energy $ω$ in the plane with cuts $(-\infty,-1],[+1,+\infty)$. In the elastic case it reduces to N functions $S_{i}(ω)$ connected by the crossing symmetry matrix A. The scattering of a neutral pseodoscalar meson with an arbitrary angular mome

Houari Merabet

We find the general hyper-elliptic solutions to the two-component reduced Nahm equations proposed by Hitchin et al. Elliptic solutions are a special case and can appear only for specific values of the monopole charges.

Brian P. Dolan

It is shown that the beta functions for four dimensional N=2 supersymmetric Yang-Mills theory without matter give integral curves on the moduli space some of which are geodesics of the natural metric on the moduli space. In particular the flow lines which cross-over from from the weak coupling limit (asymptotically free theory) to the singular points, repres

Valeri V. Dvoeglazov

On the basis of the first principles we derive the Barut-Wilson-Fushchich second-order equation in the (1/2,0)+(0,1/2) representation. Then we discuss the possibility of the description of various mass and spin states in such a framework.

Simon F. Ross

Extremal six-dimensional black string solutions with some non-trivial momentum distribution along the wave are considered. These solutions were recently shown to contain a singularity at the would-be position of the event horizon. In the black string geometry, all curvature invariants are finite at the horizon. It is shown that if the effects of infalling ma

Joannis Papavassiliou, Apostolos Pilaftsis

A gauge- and renormalization-group- invariant approach implemented by the pinch technique is formulated for resonant transitions involving the Higgs boson. The lineshape of the Higgs boson is shown to consist of two distinct and physically meaningful contributions: a process-independent resonant part and a process-dependent non-resonant background, which are

Andrzej Czarnecki

Searches for new physics using muons are reviewed. Particular attention is paid to muon number non-conserving processes, like the decay muon-->e+gamma and muon-electron conversion in muonic atoms. Also, experimental determinations and theoretical predictions for the muon anomalous magnetic moment are reviewed.

J. -M. Virey

In the context of HERA with polarized lepton and proton beams, we explore the sensitivity of the collider to contact interactions. We emphasize that the measurement of longitudinal spin asymmetries in such a polarized context could give some crucial informations on the chiral structure of these hypothetical new interactions.

E. A. Kuraev, A. Schiller, V. G. Serbo, D. V. Serebryakova

The lepton pair production $e^- e^+ \to e^- e^+ l^- l^+ $ or $μ^- μ^+ \to μ^- μ^+ l^- l^+ $ is studied in the dominant cross section region of scattering angles ${m_j}/{E_j} \stackrel{<}{\sim} θ_j \ll 1 $. An analytical expression is found for all 64 helicity amplitudes of these processes. The accuracy of the obtained formulae is given omitting only terms of

Miguel A. Sanchis-Lozano

We look at effective fields defined in the heavy-quark effective theory as operator-valued generalized functions on Minkowski space-time to be averaged with physically suitable smoothing functions (Gaussians of typical width the hadronic size) leading to operator-valued distributions in Hilbert space. One-heavy-quark states are thus represented by normalizab