September 1995 arXiv papers — page 10

Henrik Bruus, Niall D. Whelan

We study the effect of edge diffraction on the semiclassical analysis of two dimensional quantum systems by deriving a trace formula which incorporates paths hitting any number of vertices embedded in an arbitrary potential. This formula is used to study the cardioid billiard, which has a single vertex. The formula works well for most of the short orbits we

Paolo Cea, Leonardo Cosmai

We investigate the dual superconductivity hypothesis in pure SU(2) lattice gauge theory. We find evidence of the dual Meissner effect both in the maximally Abelian gauge and without gauge fixing. We also obtain a rather good extimation of the string tension using the value of the London penetration length.

Philip G. Ratcliffe

The analysis of hyperon semi-leptonic decay data is re-examined in the light of a recent suggestion that SU(3) symmetry breaking effects may be taken into account by applying a correction to the $F/D$ ratio obtained via naive linear extrapolation in the hyperon masses. Comparison is made with the physically better motivated approach of applying so-called cen

Giuseppe Albertini, Silvio Renato Dahmen, Birgit Wehefritz

The low-lying excitations of the asymmetric $XXZ$ spin chain are derived explicitly in the antiferromagnetic regime through the Bethe Ansatz. It is found that a massless and conformal invariant phase with central charge $c=1$ is separated from a massive phase by a line on which the low-lying excitations surprisingly scale with the lattice length as $ΔE \sim

Jacques Magnen, Vincent Rivasseau

This paper is part of a program by Feldman, Trubowitz and ourselves to construct a mathematically rigorous version of the BCS mechanism for superconductivity. In previous papers the renormalization group around the Fermi surface was defined and analyzed at all orders in perturbation theory. Non-perturbative results (also called constructive results) correspo

G. -M. Rignanese, J. -P. Michenaud, X. Gonze

Motivated by the negative thermal expansion observed for silicon between 20 K and 120 K, we present first an ab initio study of the volume dependence of interatomic force constants, phonon frequencies of TA(X) and TA(L) modes, and of the associated mode Gruneisen parameters. The influence of successive nearest neighbors shells is analysed. Analytical formula

Ken-ji Hamada

The Ward identities of the $W_{\infty}$ symmetry in two dimensional string theory in the tachyon background are studied in the continuum approach. We consider amplitudes different from 2D string ones by the external leg factor and derive the recursion relations among them. The recursion relations have non-linear terms which give relations among the amplitude

Simon F. Ross

I consider a truncation of low-energy string theory which contains two $U(1)$ gauge fields. After making some general comments on the theory, I describe a previously-obtained instanton for the pair creation of black holes when both gauge fields are non-zero, and obtain the pair creation rate by calculating its action. This calculation agrees qualitatively wi

Tomoyuki Maruyama

We simulate the fragmentation processes in the {$α$~$+$~Au~} collisions at a bombarding energy of 5 GeV/u using the simplified RQMD approach plus the statistical decay model. We find from the simulation that the angular-distribution of the intermediate mass fragments has a sideward peak, more strongly in the transverse direction than in the beam-direction, w

P. Olesen

We investigate whether dual strings could be solutions of the magnetohydrodynamics equations in the limit of infinite conductivity. We find that the induction equation is satisfied, and we discuss the Navier-Stokes equation (without viscosity) with the Lorentz force included. We argue that the dual string equations (with a non-universal maximum velocity) sho

Kazuyuki Fujii, Taro Kashiwa, Seiji Sakoda

\(\Un{N}\) coherent states over Grassmann manifold, \(\grsmn{N}{n}\simeq\Un{N}/ (\Un{n}\times \Un{N-n})\), are formulated to be able to argue the WKB-exactness, so called the localization of Duistermaat-Heckman, in the path integral representation of a character formula. The exponent in the path integral formula is proportional to an integer \(k\) that label

Kenneth Holmlund, Petter Minnhagen

The dynamics of two dimensional (2D) vortex fluctuations are investigated through simulations of the 2D Coulomb gas model in which vortices are represented by soft disks with logarithmic interactions. The simulations trongly support a recent suggestion that 2D vortex fluctuations obey an intrinsic anomalous dynamics manifested in a long range 1/t-tail in the

Chongying Dong, Haisheng Li, Geoffrey Mason

Let $V$ be a vertex operator algebra and $g$ an automorphism of finite order. We construct an associative algebra $A_g(V)$ and a pair of functors between the category of $A_g(V)$-modules and a certain category of admissible $g$-twisted $V$-modules. In particular, these functors exhibit a bijection between the simple modules in each category. We give various

K. Bresser, A. Dimakis, F. Mueller-Hoissen, A. Sitarz

A finite set can be supplied with a group structure which can then be used to select (classes of) differential calculi on it via the notions of left-, right- and bicovariance. A corresponding framework has been developed by Woronowicz, more generally for Hopf algebras including quantum groups. A differential calculus is regarded as the most basic structure n

Sanjay K. Ghosh, S. C. Phatak, P. K. Sahu

The neutrino emissivity of compact stars is investigated in this work. We consider stars consisting of nuclear as well as quark matter for this purpose. Different models are used to calculate the composition of nuclear and quark matter and the neutrino emissivity. Depending on the model under consideration, the neutrino emissivity of nuclear as well as quark

Sanjay K. Ghosh, S. C. Phatak, P. K. Sahu

Production of strange quarks in neutron stars is investigated in this work. Three cases, one in which the energy and neutrinos produced in the strangeness production reactions are retained in the reaction region, second in which the neutrinos are allowed to escape the reaction region but the energy is retained and the third in which both the energy and neutr

A. V. Postnikov, St. Bartkowski, F. Mersch, M. Neumann

The x-ray photoelectron valence band spectrum and x-ray emission valence-band spectra (Ti K _beta_5, Ti L_alpha, O K_alpha) of Bi4Ti3O12 are presented (analyzed in the common energy scale) and interpreted on the basis of a band-structure calculation for an idealized I4/mmm structure of this material.

Victor O. Rivelles

We show that recently found symmetries in QED are just non-local versions of standard BRST symmetry.

Alex C. Kalloniatis

SU(2) Yang-Mills Theory coupled to massive adjoint scalar matter is studied in (1+1) dimensions using Discretised Light-Cone Quantisation. This theory can be obtained from pure Yang-Mills in 2+1 dimensions via dimensional reduction. On the light-cone, the vacuum structure of this theory is encoded in the dynamical zero mode of a gluon and a constrained mode

Leon A. Takhtajan

We show equivalence between the standard weak coupling regime c>25 of the two-dimensional quantum gravity and regime h<1/2 of the original geometric approach of Polyakov [1,2], developed in [3,4,5].

A. Yu. Volkov

A quantum theory is developed for a difference-difference system which can serve as a toy-model of the quantum Korteveg-de-Vries equation.

John F. Donoghue, Jusak Tandean

We discuss the various resolutions which have been suggested in the literature for the way that the equivalence theorem can be satisfied in theories with global anomalies. We provide a model-independent proof for the resolution originally suggested in the context of a toy model by Kilgore.

Arjun Berera, Davison E. Soper

Diffractive parton distribution functions give the probability to find a parton in a hadron if the hadron is diffractively scattered. We provide an operator definition of these functions and discuss their relation to diffractive deeply inelastic scattering and to photoproduction of jets at HERA. We perform a calculation in the style of ``constituent counting

S. V. Goloskokov

It is shown that the longitudinal double spin asymmetry $A_{ll}$ in polarized diffractive $Q \bar Q$ production depends strongly on the spin structure of the quark-pomeron vertex. Relevant experiments will be possible at HERA with a polarized proton beam.

M. Stratmann, A. Weber, W. Vogelsang

We study in detail the flavor-non-singlet component of polarized structure functions in the framework of a consistent and complete next-to-leading order (${\cal O}(α_s))$ analysis. In this context, we discuss some important features of the calculation of the next-to-leading order corrections. Particular emphasis is put on the $Q^2$-evolution of sum-rules for

Torbjorn Sjostrand

This talk contains a subjective selection of interesting results on Z$^0$ decays, presented by the LEP and SLC groups. The emphasis is on soft and semihard QCD physics. Results are put in a theoretical context, and the limits of our current understanding are stressed. Topics covered include event measures, prompt photons, coherence and string effects, data a

Q. Z. Chen, S. H. Guo, X. Q. Luo, A. Segui

We discuss the relevance of long wavelength excitations for the low energy spectrum of QCD, and try to develop an efficient method for solving the Schrodinger equation, and for extracting the glueball masses and long wavelength functions of the ground and excited states. Some technical problems appearing in the calculations of SU(3) gauge theory are discusse

Enrico Nardi

We analyze the effects of a tree level flavor changing $tcZ$ vertex induced by a mixing with new isosinglet $Q=2/3$ quarks, on the effective $bsZ$ vertex. We compute the contributions arising from the new electroweak penguin diagrams involving one insertion of the $tcZ$ vertex. We show that a generalized GIM mechanism ensures the cancellation of the mass ind

Takayuki Matsuki, Toshiyuki Morii

Assuming Coulomb-like as well as confining scalar potential, we have solved Shrödinger equation perturbatively in $1/m_Q$ with a heavy quark mass $m_Q$. The lowest order equation is examined carefully. Mass levels are fitted with experimental data for $D/B$ mesons at each level of perturbation. Meson wave functions obtained thereby can be used to calculate o

S. V. Faleev, P. G. Silvestrov

The instanton--anti-instanton pair induced asymptotics of perturbation theory expansion for the cross section of electron--positron pair annihilation to hadrons and hadronic width of $τ$-lepton was found. For $N_f = N_c$ the nonperturbative instanton contribution is finite and may be calculated without phenomenological input. The instanton induced peturbativ

Marina Artuso

The CLEO detector will undergo major improvements in conjunction with a high luminosity upgrade of the CESR electron positron collider, that should increase the luminosity of this machine by a factor of 10. The most innovative feature of the planned CLEO detector is the addition of a state of the art particle identification system, based on a proximity focus

Sheldon Stone

The symmetric $e^+e^-$ collider CESR is undergoing a series of upgrades allowing for luminosities in excess of $2\times 10^{33}$cm$^{-2}$s$^{-1}$. The most important goals of the upgrade are precision measurement of standard model parameters $V_{cb}$, $V_{ub}$, $V_{td}/V_{ts}$, $f_{D_s}$, and searching for CP violation and standard model violations in rare $

O. V. Babourova, B. N. Frolov

The variational theory of the perfect fluid with an intrinsic hypermomentum is developed. The Lagrangian density of such fluid is stated and the equations of motion of the fluid and the evolution equation of the hypermomentum tensor are derived. The expressions of the matter currents of the fluid (the metric stress-energy 4-form, the canonical energy-momentu

R. R. Caldwell, Paul Casper

The fraction of cosmic string loops which collapse to form black holes is estimated using a set of realistic loops generated by loop fragmentation. The smallest radius sphere into which each cosmic string loop may fit is obtained by monitoring the loop through one period of oscillation. For a loop with invariant length $L$ which contracts to within a sphere

Robin W Tucker, Charles Wang

A simple modification to Einstein&#39;s theory of gravity in terms of a non-Riemannian connection is examined. A new tensor-variational approach yields field equations that possess a covariance similar to the gauge covariance of electromagnetism. These equations are shown to possess solutions analogous to those found in the Einstein-Maxwell system. In partic

H. Ishihara, H. Kubotani, T. Fukuyama

Gravitational instantons of Bianchi type IX space are constructed in Ashtekar&#39;s canonical formalism. Instead of solving the self-duality condition, we fully solve the constraint on the ``initial surface&#39;&#39; and ``Hamiltonian equations&#39;&#39;. This formalism is applicable to the matter coupled system with cosmological constant.

Jiro Soda, Hideki Ishihara, Osamu Iguchi

Hamilton-Jacobi equation for Brans-Dicke theory is solved by using a long-wavelength approximation. We examine the non-linear evolution of the inhomogeneities in the dust fluid case and the cosmological constant case. In the case of dust fluid, it turns out that the inhomogeneities of space-time grow. In the case of cosmological constant, the inhomogeneities

Giampiero Esposito

We study a $R^{2}$ model of gravity with torsion in a closed Friedmann-Robertson-Walker universe. The model is cast in Hamiltonian form subtracting from the original Lagrangian the total time derivative of $f_{K}f_{R}$, where $f_{K}$ is proportional to the trace of the extrinsic curvature tensor, and $f_{R}$ is obtained differentiating the Lagrangian with re

Jun&#39;ichi Yokoyama

Making use of the primordially isocurvature fluctuations, which are generated in inflationary models with multiple scalar fields, we make a phenomenological model that predicts formation of primordial black holes which can account for the massive compact halo objects recently observed.

Sergey A. Merkulov

This paper is a review of the twistor theory of irreducible G-structures and affine connections. Long ago, Berger presented a very restricted list of possible irreducibly acting holonomies of torsion-free affine connections. His list was complete in the part of metric connections, while the situation with holonomies of non-metric torsion-free affine connecti

James A. Feigenbaum, Peter G. O. Freund

We propose a picture of stock market crashes as critical points in a hierachical system with discrete scaling. The critical exponent is then complex, leading to log-periodic fluctuations in stock market indexes. We present ``experimental&#39;&#39; evidence in favor of this prediction. This picture is in the spirit of the known earthquake-stock market analogy

S. W. Sides, R. A. Ramos, P. A. Rikvold, M. A. Novotny

The S=1/2, nearest-neighbor, kinetic Ising model has been used to model magnetization switching in nanoscale ferromagnets. For this model, earlier work based on the droplet theory of the decay of metastable phases and Monte Carlo simulations has shown the existence of a size dependent spinodal field which separates deterministic and stochastic decay regimes.

J. J. Palacios, A. H. MacDonald

We report on microscopic numerical studies which support the chiral Luttinger liquid theory of the fractional Hall edge proposed by Wen. Our calculations are based in part on newly proposed and accurate many-body trial wavefunctions for the low-energy edge excitations of fractional incompressible states.

M. Hébert, M. L. Plumer

We present the phase diagram and critical properties of a coupled $XY$-Ising model on a triangular lattice using the mean-field approximation, the Migdal-Kadanoff scheme of renormalization group and Monte-Carlo simulations. The topology of the phase diagram is similar for the three techniques, with the appearance of a phase with $XY$ order and Ising disorder

Shubha Tewari, John Ruvalds

Electron collisions for a two dimensional Fermi liquid (FL) are shown to give a quasiparticle damping with interesting frequency and temperature variations in the BCS superconducting state. The spin susceptibility which determines the structure of the damping is analyzed in the normal state for a Hubbard model with a constant on--site Coulomb repulsion. This

Pavel Exner, Ralf Gawlista

We consider rectangular graph superlattices of sides l1, l2 with the wavefunction coupling at the junctions either of the delta type, when they are continuous and the sum of their derivatives is proportional to the common value at the junction with a coupling constant alpha, or the &#34;delta-prime-S&#34; type with the roles of functions and derivatives reve

Igor F. Herbut, Zlatko Tesanovic

We calculate the transition line of the first-order melting of vortex lattice in a three-dimensional type-II superconductor in fields of several Tesla, using the results from the density-functional theory of vortex melting in two dimensions and the self-consistent Hartree treatment of correlations along the field. The result is in quantitative agreement with

G. Benettin, A. Carati, G. Gallavotti

Rigorous bounds on the rate of energy exchanges between vibrational and translational degrees of freedom are established in simple classical models of diatomic molecules. The results are in agreement with an elementary approximation introduced by Landau and Teller. The method is perturbative theory ``beyond all orders&#39;&#39;, with diagrammatic techniques

Carlberg, Yee, Ellingson, Abraham

To re-examine the rich cluster $Ω$ value the CNOC Cluster Survey has observed 16 high X-ray luminosity clusters in the redshift range 0.17 to 0.55, obtaining approximately 2600 velocities in their fields. Directly adding all the K and evolution corrected $r$ band light to $M_r(0)=-18.5$, about $0.2L_\ast$, and correcting for the light below the limit, the av

Bhuvnesh Jain

The scaling ansatz of Hamilton et al. effectively extends the idea of self-similar scaling to initial power spectra of any generic shape. Applications of this ansatz have provided a semi-empirical analytical description of gravitational clustering which is extremely useful. This contribution examines the two theoretical ingredients that form the basis of the

Jesus Pando, Li-Zhi Fang

A method for measuring the spectrum of a density field by a discrete wavelet space-scale decomposition (SSD) has been studied. We show how the power spectrum can effectively be described by the father function coefficients (FFC) of the wavelet SSD. We demonstrate that the features of the spectrum, such as the magnitude, the index of a power law, and the typi

John N. Bahcall, Sofia Kirhakos, Donald P. Schneider

HST images (with WFPC2) of PHL~909\ ($z = 0.171$) and PG~0052$+$251\ ($z = 0.155$) show that these luminous radio-quiet quasars each occur in an apparently normal host galaxy. The host galaxy of PHL~909 is an elliptical galaxy ($\sim$ E4) and the host of PG~0052$+$251 is a spiral ($\sim$~Sb). Both host galaxies are several tenths of a magnitude brighter than

M. Unavane, R. F. G. Wyse, G. F. Gilmore

The age distribution, and chemical elemental abundances, of stars in the halo of the Milky Way provide constraints on theories of galaxy formation. As one specific example, the accretion of satellite galaxies similar to the present retinue of dwarf spheroidals (dSphs) would provide an observable metal-poor, intermediate-age population. This paper presents a

Priyamvada Natarajan, Jean-Paul Kneib

Weak shear maps of the outer regions of clusters have been successfully used to map the distribution of mass at large radii. The effects of substructure in clusters on such reconstructions of the total mass have not been systematically studied. We propose a new method to study the effect of perturbers (bright cluster galaxies or sub-groups within the cluster

J. N. Bahcall, S. Kirhakos, D. P. Schneider, R. J. Davis

We present red and blue images of the jet of the quasar 3C273 obtained with the WFPC2 on the Hubble Space Telescope as well as a new radio map made with the MERLIN array. The images are of significantly better quality than that of previous data. The two maps are aligned to an accuracy of 0.020$&#39;&#39;$; this accuracy is achieved because both the quasar an

Jun&#39;ichi Yokoyama

As a nonbaryonic explanation of massive compact halo objects, a phenomenological model is presented which predicts formation of primordial black holes at a desired mass scale. The required feature of initial density fluctuation is realized making use of the primordially isocurvature fluctuation generated in an inflationary universe model with multiple scalar

A. Valcarce, P. Gonzalez, F. Fernandez, V. Vento. The discussion is now improved

By solving the Schrödinger equation for the three-quark system in the hyperspherical harmonic approach, we have studied the low energy part of the nucleon and $Δ$ spectra using a quark-quark interaction which reproduces the nucleon-nucleon phenomenology. The quark-quark hamiltonian considered includes, besides the usual one-gluon exchange, pion and sigma exc

O. V. Kovalev, Yu. M. Pis&#39;mak, V. V. Vechernin

The modification of the model of P.Bak and K.Sneppen of the self-organized biological evolution is proposed on the basis of a formalization of the scheme of the biosphere evolution suggested by O.V.Kovalev. This scheme is regarded as one approximating the realistic model of the ecosystem evolution. The fundamental difference between &#34;coenophilous&#34; sp

Frederik G Schotlz, Sergei V. Shabanov

We develop a new operator quantization scheme for gauge theories in which the dynamics of the ghost sector is described by an N=2 supersymmetry. In this scheme no gauge condition is imposed on the gauge fields. The corresponding path integral is explicitly Lorentz invariant and, in contrast to the BRST-BFV path integral in the Lorentz gauge, it is free of th

Hai-Yang Cheng, Hung Hsiang Liu, Chung-Yi Wu

The hard-gluonic contribution to the first moment of the polarized proton structure function $g_1^p(x)$ is dependent of the factorization convention chosen in defining the quark spin density and the hard cross section for photon-gluon scattering. Two extremes of interest, namely gauge-invariant and chiral-invariant factorization schemes, are considered. We s

Arvind, B. Dutta, N. Mukunda, R. Simon

text of abstract (We present a utilitarian review of the family of matrix groups $Sp(2n,\Re)$, in a form suited to various applications both in optics and quantum mechanics. We contrast these groups and their geometry with the much more familiar Euclidean and unitary geometries. Both the properties of finite group elements and of the Lie algebra are studied,

Luc Lapointe, Luc Vinet

The wave functions of the Calogero-Sutherland model are known to be expressible in terms of Jack polynomials. A formula which allows to obtain the wave functions of the excited states by acting with a string of creation operators on the wave function of the ground state is presented and derived. The creation operators that enter in this formula of Rodrigues-

Luc Lapointe, Luc Vinet

A formula of Rodrigues-type for the Jack polynomials is presented. It is seen to imply a weak form of a conjecture of Macdonald and Stanley.

Ralf A. Engeldinger

A method to calculate matrix representations of the twist element $\ff$ of Drinfel&#39;d -- chosen to be unitary -- is given and illustrated at some examples. It is observed that for these F-matrices the crystal limit $q\!\to\! 0$ exists and that \mbox{F-matrices} twisting from $0$ to $q$ are of a simpler form than F-matrices twisting from $1$ to $q$. These

G. Kortemeyer, W. Bauer, K. Haglin, J. Murray

Transport models have successfully described many aspects of intermediate energy heavy-ion collision dynamics. As the energies increase in these models to the ultrarelativistic regime, Lorentz covariance and causality are not strictly respected. The standard argument is that such effects are not important to final results; but they have not been seriously co

A. Valcarce, F. Fernandez, H. Garcilazo

Based on a quark cluster model for the non-strange sector that reproduces reasonably well the nucleon-nucleon system and the excitation of the $Δ$ isobar, we generate a nucleon-$Δ$ interaction and present the predictions for the several isospin two channels. The only attractive channels are $0^+$ and $0^-$, but not attractive enough to generate a resonance.

Kevin Haglin, Charles Gale

We consider lepton pair production via two-hadron annihilation through various isoscalar vector mesons within hot, baryon-free matter. This is tantamount to constructing effective form factors which we model using a vector-meson-dominance approach and compare with experiment. In particular, we consider the reactions $πρ\to e^+e^-$ and $\bar K K^{*}(892)$ + c

H. Sorge

Collective interactions in the preequilibrium quark matter and hadronic resonance gas stage of ultrarelativistic nucleus-nucleus collisions are studied in the framework of the the transport theoretical approach RQMD. The paper reviews string fusion into color ropes and hadronic rescattering which serve as models for these interactions. Hadron production in c

M. Hjorth-Jensen, H. Muether, A. Polls, E. Osnes

The convergence of the perturbation expansion for the effective interaction to be used in shell-model calculations is investigated as function of the mass number $A$, from $A=4$ to $A=208$. As the mass number increases, there are more intermediate states to sum over in each higher-order diagram which contributes to the effective interaction. Together with th

S. J. Gates,, M. T. Grisaru, M. E. Wehlau

We study two-dimensional N=2 supersymmetric actions describing general models of scalar and vector multiplets coupled to supergravity.

H. C. Pauli, A. C. Kalloniatis, S. S. Pinsky

We formulate QCD in (d+1) dimensions using Dirac&#39;s front form with periodic boundary conditions, that is, within Discretized Light-Cone Quantization. The formalism is worked out in detail for SU(2) pure glue theory in (2+1) dimensions which is approximated by restriction to the lowest {\it transverse} momentum gluons. The dimensionally-reduced theory tur

A. P. Balachandran, L. Chandar, B. Sathiapalan

In previous work on the quantum Hall effect on an annulus, we used $O(d,d;{\bf Z})$ duality transformations on the action describing edge excitations to generate the Haldane hierarchy of Hall conductivities. Here we generate the corresponding hierarchy of ``bulk actions&#39;&#39; which are associated with Chern-Simons (CS) theories, the connection between th

Hidenori Sonoda

In a previous paper, field theory in curved space was considered, and a formula that expresses the first order variation of correlation functions with respect to the external metric was postulated. The formula is given as an integral of the energy-momentum tensor over space, where the short distance singularities of the product of the energy-momentum tensor

Elias Kiritsis, Costas Kounnas

Exact Superstring solutions are constructed moving in 4-D space-time with positive curvature and non-trivial dilaton and antisymmetric tensor fields. The full spectrum of string excitations is derived as a function of moduli fields $T^{i}$ and the scale $μ^2=1/(k+2)$ which induced by the non-zero background fields. The spectrum of string excitations has a no

V. Brindejonc, G. Cohen-Tannoudji

We show that, when quantized on a curved ``intra-hadronic background&#39;&#39;, QCD induces an effective pseudo gravitational interaction with gravitational and cosmological constants in the GeV range.

D. K. Park

New prescription for the singularities of light-cone gauge theories is suggested. The new prescription provides Green&#39;s function which is identical with and different from that of Mandelstam-Leibbrandt prescription at $d=4$ and $d=2$ respectively.

S. Veseli, M. G. Olsson

We apply HQET to semi-leptonic $B$ and $B_{s}$ meson decays into the observed charmed $P$ wave states. In order to examine the sensitivity of the results to the choice of a specific model, we perform all calculations using several different meson models, and find that uncertainty introduced by the choice of a particular model is about 30\%. Specifically, ass

J. L. Diaz Cruz, J. J. Godina Nava, G. Lopez Castro

We study a model with two Higgs doublets where FCNC are allowed at tree-level. In this model, the interactions of charged Higgs with fermions ($H^\pm f \bar{f&#39;}$), include a term that is not proportional to the fermion masses, which we constraint using the following low-energy processes: i) tau decays ($τ\to ν_τ eν_e, ν_τμν_μ, ν_τπ$), ii) leptonic decays

S. Nussinov

We consider versions of the Casimir effect where the force can be controlled by changing the angle between two Casimir ``plates&#39;&#39; or the temperature of two nearby rings. We also present simple arguments for the sign of Casimir forces.

Antonio Dobado, Antonio L. Maroto

Using the Fujikawa and the heat-kernel methods we make a complete and detailed computation of the global, gauge and gravitational anomalies present in the Standard Model defined on a curved space time with torsion. We find new contributions coming from curvature and torsion terms to the leptonic number anomaly (so that $B-L$ is not conserved any more), to th

M. Burkardt

In the limit of an infinite number of colors, an analytic expression for the quark condensate in $QCD_{1+1}$ is derived as a function of the quark mass and the gauge coupling constant. For zero quark mass, a nonvanishing quark condensate is obtained. Nevertheless, it is shown that there is no phase transition as a function of the quark mass. It is furthermor

Claude Bourrely, Jacques Soffer

Some simple relations between unpolarized and polarized quark parton distributions have direct experimental consequences which will be presented here. In particular, we will see that it is possible to relate the deep inelastic structure functions $F_2$ and $g_1$, both for proton and deuteron, in fair agreement with experimental data.

D. Gromes

We use a very simple version of the optimized (linear) $δ$ - expansion by scaling the free part of the Lagrangian with a variational parameter. This method is well suited to calculate the renormalized coupling constant in terms of the free one and the cutoff. One never has to calculate any new Feynman graphs but simply can modify existing results from the li

Masud Chaichian, Ricardo Gonzalez Felipe, Katri Huitu

The quadratic divergences in the scalar sector of the standard model are considered. Since the divergences are present also in the unbroken theory, a natural scale for the divergence formula is proposed to be at the scale of new physics. The implications of top quark mass on the Higgs mass are investigated by means of the renormalization group equations. The

A. J. van der Sijs

I report on the development of RTNN, a parallel computer designed as a 4^4 hypercube of 256 T9000 transputer nodes, each with 8 MB memory. The peak performance of the machine is expected to be 2.5 Gflops.

M. Campostrini, A. Pelissetto, P. Rossi, E. Vicari

The renormalized zero-momentum four-point coupling $g_r$ of $O(N)$-invariant scalar field theories in $d$ dimensions is studied by applying the $1/N$ expansion and strong coupling analysis. The $O(1/N)$ correction to the $β$-function and to the fixed point value $g_r^*$ are explictly computed. Strong coupling series for lattice non-linear $σ$ models are anal

D. F. Agterberg, M. B. Walker

We show that a recent measurement of surface superconductivity in UPt$_3$ (Keller {\it et. al.}, Phys. Rev. Lett. {\bf 73}, 2364 (1994)) can be understood if the superconducting pair wavefunction is suppressed anisotropically at a vacuum to superconductor interface. Further measurements of surface superconductivity can distinguish between the various phenome

P. Chandra, M. V. Feigelman, L. B. Ioffe

We present an analytic study of a dynamical instability in a periodic long-range Josephson array frustrated by a weak transverse field. This glass transition is characterized by a diverging relaxation time and a jump in the Edwards-Anderson order parameter; it is {\sl not} accompanied by a coinciding static transition.

R. K. Bhaduri, Akira Suzuki

We show that the single quasi-particle Schrödinger equation for a certain form of one-body potential yields a stationary one soliton solution. The one-body potential is assumed to arise from the self- interacting charge distribution with the singular kernel of the Calogero-Sutherland model. The quasi-particle has negative or positive charge for negative or p

G. Varelogiannis, L. Pietronero

We address the question of whether boson mediators of high-$T_c$ superconductivity are composite (electronic) or independent phonons. For s-wave superconductivity we show from the available experiments that the hypothesis of composite bosons is rather unlikely. Our analysis points naturally towards phonon mediators. In addition we point out that the eventual

J. P. Hessling, V. S. Shumeiko, Yu. M. Galperin, G. Wendin

Non-equilibrium excess noise of a short quasi one-dimensional constriction between two superconductors is considered. A general expression for the current-current correlation function valid for arbitrary temperatures and bias voltages is derived. This formalism is applied to a current-carrying quantum channel with perfect transparency. Contrary to a transpar

Yasumasa Hasegawa, Mitake Miyazaki

The superconductivity of quasi-one-dimensional electrons in the magnetic field is studied. The system is described as the one-dimensional electrons with no frustration due to the magnetic field. The interaction is assumed to be attractive between electrons in the nearest chains, which corresponds to the lines of nodes of the energy gap in the absence of the

Mahendra K. Verma

In this paper we calculate the turbulent heating rates in the solar wind using the Kolmogorov-like MHD turbulence phenomenology with Kolmogorov&#39;s constants calculated by {\it Verma and Bhattacharjee }[1995b,c]. We find that the turbulent heating can not account for the total heating of the nonAlfvénic streams in the solar wind. We show that dissipation d

Mahendra K. Verma, Jayant K. Bhattacharjee

In this paper we apply Kraichnan&#39;s direct interaction approximation, which is a one loop perturbation expansion, to magnetohydrodynamic turbulence. By substituting the energy spectra both from kolmogorov-like MHD turbulence phenomenology and a generalization of Dobrowolny et al.&#39;s model we obtain Kolmogorov&#39;s and Kraichnan&#39;s constant for MHD

Mahendra K. Verma

In this paper we have estimated typical anomalous viscosity, resistivity, and thermal difffusivity of the solar wind plasma. Since the solar wind is collsionless plasma, we have assumed that the dissipation in the solar wind occurs at proton gyro radius through wave-particle interactions. Using this dissipation length-scale and the dissipation rates calculat

Mahendra K. Verma, Jayant K. Bhattacharjee

In this paper we calculate Kolmogorov&#39;s constant for magnetohydrodynamic turbulence to one loop order in perturbation theory using the direct interaction approximation technique of Kraichnan. We have computed the constants for various $E^u(k)/E^b(k)$, i.e., fluid to magnetic energy ratios when the normalized cross helicity is zero. We find that $K$ incre

A. R. Prasanna, Subhendra Mohanty

We study the observational consequences of the leading order P and T violating gauge invariant graviton-photon interactions. Such interactions give rise to gravitational birefringence - the velocity of light signals depends upon their polarisation, which is absent in Einstein&#39;s gravity. Using experimentally established limits on the differential time del

Hui Li, Edison P. Liang

We study quantitatively the formation and radiation acceleration of electron-positron pair plasmoids produced by photon-photon collisions near Galactic black holes (GBHs). The terminal ejecta velocity is found to be completely determined by the total disk luminosity, proton loading factor and disk size, with no dependence on the initial velocity. We discuss

P. L. Nolan

The EGRET instrument aboard the Compton Gamma Ray Observatory (CGRO) has completed the first all-sky survey in high-energy gamma rays and has repeatedly viewed selected portions of the sky. Analysis of the region with galactic latitude $+10\arcdeg < b < +40\arcdeg$ indicates the presence of nineteen point sources, including nine which can be identified as ac

Anshu Gupta, Subhendra Mohanty, Manoj K. Samal

Charged particles in the geodesic trajectory of an external gravitational field do not emit electromagnetic radiation. This is expected from the application of the equivalence principle. We show here that charged particles propagating in an external gravitational field with non-zero components of the Ricci tensor can emit radiation by the Čerenkov process. T