December 1995 arXiv papers — page 10

J. Rozanski

For an Yang Baxter operator we show that a bialgebra homomorphism from a free braided tensor bialgebra to a cofree braided shuffle bialgebra is the Woronowicz braided antisymmetrizer. A cofree braided shuffle bialgebra is a braided generalization of a cofree shuffle bialgebra introduced by Sweedler. Its graded dual bialgebra is a free braided tensor bialgebr

J. L. Friar, D. G. Madland, B. W. Lynn

The role of QCD scales and chiral symmetry in finite nuclei is examined. The Dirac-Hartree mean-field coupling constants of Nikolaus, Hoch, and Madland (NHM) are scaled in accordance with the QCD-based prescription of Manohar and Georgi. Whereas the nine empirically-based coupling constants of NHM span thirteen orders of magnitude, the scaled coupling consta

Abhee K. Dutt-Mazumder, Anirban Kundu, Binayak Dutta-Roy, Triptesh De

Qualitative changes in the collective excitation spectra of the $ρ$-meson triplet in neutron matter is studied, with particular emphasis on the breaking of the discrete $p\leftrightarrow n$ symmetry. The appearance of additional branches in the dispersion characteristics, the mass splitting among the charge states, the splitting between longitudinal and tran

J. Terasaki, P. -H. Heenen, H. Flocard, P. Bonche

We investigate the possibility of describing triaxial quadrupole deformations for nuclei close to the two-neutron drip line by the Hartree-Fock Bogoliubov method taking into account resonances in the continuum. We use a Skyrme interaction to describe the Hartee-Fock hamiltonian and a density-dependent zero-range interaction to evaluate the pairing field. The

J. Dobaczewski, W. Nazarewicz, T. R. Werner, J. F. Berger

Ground-state properties of exotic even-even nuclei with extreme neutron-to-proton ratios are described in the framework of the self-consistent mean-field theory with pairing formulated in coordinate space. This theory properly accounts for the influence of the particle continuum, which is particularly important for weakly bound systems. The pairing propertie

Ryoichi Seki, T. D. Shoppa, Akihisa Kohama, Koichi Yazaki

Nuclear transparency is calculated for high-energy, semi-inclusive $(e,e'p)$ reactions, by accounting for all orders of Glauber multiple-scattering and by using realistic finite-range $p N$ interaction and (dynamically and statistically) correlated nuclear wave functions. The nuclear correlation effect is reduced due to the $p N$ finite-range effect. The

Michael Christ, Georgi Karadzhov

A necessary and sufficient condition for local solvability is presented for the linear partial differential operators $-X^2-Y^2+ia(x)[X,Y]$ in $\bold R^3=\{(x,y,t)\}$, where $X=\partial_x,\; Y=\partial_y+x^k\partial_t$, and $a\in C^{\infty}(\bold R^1)$ is real valued, for each positive integer $k$.

Xiaojun Huang

We study the regularity results of holomorphic correspondences. As an application, we combine it with certain recently developed methods to obtain the extension theorem for proper holomorphic mappings between domains with real analytic boundaries in the complex 2-space.

A. Skorik, Mikhail Zaidenberg

We obtain the following characterization of Hilbert spaces. Let $E$ be a Banach space whose unit sphere $S$ has a hyperplane of symmetry. Then $E$ is a Hilbert space iff any of the following two conditions is fulfilled: a) the isometry group ${\rm Iso}\, E$ of $E$ has a dense orbit in S; b) the identity component $G_0$ of the group ${\rm Iso}\, E$ endowed wi

Mikhail Zaidenberg

The main result says that every surjective isometry between two ideal Banach function spaces satisfying certain conditions can be presented as a composition of a measurable transformation of a variable and multiplication by a function.

Yu. M. Zinoviev

A model describing the $N=2$ supergravity interaction with vector and linear multiplets is constructed. It admits the introduction of the spontaneous breaking of supersymmetry with arbitrary scales, one of which may be equal to zero, which corresponds to partial super-Higgs effect ($N=2 \rightarrow N=1$). A cosmological term is automatically equal to zero.

C. Klimcik, P. Severa

A duality invariant first order action is constructed on the loop group of a Drinfeld double. It gives at the same time the description of both of the pair of $σ$-models related by Poisson-Lie T-duality. Remarkably, the action contains a WZW-term on the Drinfeld double not only for conformally invariant $\si$-models. The resulting actions of the models from

S. E. Konstein, M. A. Vasiliev

We define a complete set of supertraces on the algebra $SH_N(ν)$, the algebra of observables of the $N$-body rational Calogero model with harmonic interaction. This result extends the previously known results for the simplest cases of $N=1$ and $N=2$ to arbitrary $N$. It is shown that $SH_N(ν)$ admits $q(N)$ independent supertraces where $q(N)$ is a number o

A. Dubin, D. Wyler

A variety of unitary gauges for perturbation theory in a background field is considered in order to find those most suitable for a Hamiltonian treatment of the system. We select two convenient gauges and derive the propagators $D_{μν}$ for gluonic quantum fluctuations immersed in background configurations. The first one is a unitary generalization of the usu

A. A. Deriglazov, A. V. Galajinsky, S. L. Lyakhovich

The general procedure of constructing a consistent covariant Dirac-type bracket for models with mixed first and second class constraints is presented. The proposed scheme essentially relies upon explicit separation of the initial constraints into infinitely reducible first and second class ones (by making use of some appropriately constructed covariant proje

B. M. Zupnik

We consider the $SYM^1_6$ harmonic-superspace system of equations that contains superfield constraints and equations of motion for the simplest six-dimensional supersymmetric gauge theory. A special $A$-frame of the analytic basis is introduced where a kinematic equation for the harmonic connection $A^{\s--}$ can be solved . A dynamical equation in this fram

Costas Kounnas

Some of the four-dimensional Superstring solutions provide a consistent framework for a Supersymmetric Unification of all interactions including gravity. A class of them extends successfully the validity of the standard model up to the string scale ${\cal O}(10^{17})~GeV$. We stress the importance of string corrections which are relevant for low energy ${\ca

Peter Bouwknegt, Jim Mccarthy, Krzysztof Pilch

Given a simple, simply laced, complex Lie algebra $\bfg$ corresponding to the Lie group $G$, let $\bfnp$ be the subalgebra generated by the positive roots. In this paper we construct a BV-algebra $\fA[\bfg]$ whose underlying graded commutative algebra is given by the cohomology, with respect to $\bfnp$, of the algebra of regular functions on $G$ with values

I. Bakas, Q-Han Park, H. J. Shin

The symmetric space sine-Gordon models arise by conformal reduction of ordinary 2-dim $σ$-models, and they are integrable exhibiting a black-hole type metric in target space. We provide a Lagrangian formulation of these systems by considering a triplet of Lie groups $F \supset G \supset H$. We show that for every symmetric space $F/G$, the generalized sine-G

M. Goshtasbpour, Gordon P. Ramsey

We have used recent polarized deep-inelastic scattering data from CERN and SLAC to extract information about nucleon spin structure. We find that the SMC proton data, the E142 neutron data and the deuteron data from SMC and E143 give different results for fractions of the spin carried by each of the constituents. These appear to lead to two different and inc

Robert J. Oakes

A formula for an improved spin--dependent potential between a heavy quark and a heavy antiquark was developed using Heavy Quark Effective Theory techniques. The leading logarithmic quark mass terms emerging from loop contributions were explicitly extracted and summed up. There is no renormalization scale dependence in this new formula and it includes both th

J. F. Amundson, O. J. P. E'boli, E. M. Gregores, F. Halzen

We point out that an unorthodox way to describe the production of rapidity gaps in deep inelastic scattering, recently proposed by Buchm\"uller and Hebecker, suggests a description of the production of heavy quark bound states which is in agreement with data. The approach questions the conventional treatment of the color quantum number in perturbative QCD.

M. Cacciari, M. Greco, B. A. Kniehl, M. Krämer

The next-to-leading-order (NLO) cross section for the production of heavy quarks at large transverse momenta ($p_\perp$) in $γγ$ collisions is calculated with perturbative fragmentation functions (PFF's). This approach allows for a resummation of terms $\proptoα_s\ln(p_\perp^2/m^2)$ which arise in NLO from collinear emission of gluons by heavy quarks at

Jihn E. Kim

After a brief review of the axion solution of the strong CP problem, its supersymmetric extension and the superstring axion are discussed. I also present one interesting cosmological scenario, the axino-gravitino cosmology, for the large scale structure of the universe.

S. Kumano, M. Miyama

$Q^2$ evolution of the structure functions $F_2$ in tin and carbon nuclei is investigated in order to understand recent NMC measurements. $F_2$ is evolved by using leading-order DGLAP, next-to-leading-order DGLAP, and parton-recombination equations. NMC experimental result $\partial [F_2^{Sn}/F_2^C]/ \partial [\ln Q^2]\ne 0$ could be essentially understood b

Laszlo B Szabados

In the present paper the determination of the {\it pp}-wave metric form the geometry of certain spacelike two-surfaces is considered. It has been shown that the vanishing of the Dougan--Mason quasi-local mass $m_{\$}$, associated with the smooth boundary $\$:=\partialΣ\approx S^2$ of a spacelike hypersurface $Σ$, is equivalent to the statement that the Cauch

P. Fraundorf

When introducing special relativity, an elegant connection to familiar rules governing Galilean constant acceleration can be made, by describing first the discovery at high speeds that the clocks (as well as odometers) of different travelers may proceed at different rates. One may then show how to parameterize any given interval of constant acceleration with

Daniel W. Hone, Xian-Geng Zhao

We use an analytic perturbation expansion for the two-band system of tight binding electrons to discuss Bloch oscillations and Zener tunneling within this model. We make comparison with recent numerical results and predict analytically the frequency of radiation expected from Zener tunneling, including its disappearance, as a function of the system parameter

Martin Ulmke

The Hubbard model on the fcc lattice is studied in the limit of infinite spatial dimensions. At sufficiently strong interaction finite temperature Quantum Monte Carlo calculations yield a second order phase transition to a highly polarized ferromagnetic state. Ferromagnetism is stable over a wide hole doping regime but not for electron doping. A possible non

A. H. MacDonald

When the quantum Hall effect occurs in a two-dimensional electron gas, all low-energy elementary excitations are localized near the system edge. The edge acts in many ways like a one-dimensional ring of electrons, except that a finite current flows around the ring in equilibrium. This article is a brief and informal review of some of the physics of quantum H

H. S. Bokil, A. P. Young

We study the chirality in the Villain form of the XY spin glass in two--dimensions by Monte Carlo simulations. We calculate the chiral-glass correlation length exponent $ν_{\scriptscriptstyle CG}$ and find that $ν_{\scriptscriptstyle CG} = 1.8 \pm 0.3$ in reasonable agreement with earlier studies. This indicates that the chiral and phase variables are decoup

J. Schiøtz, A. E. Carlsson, L. M. Canel, Robb Thomson

Theories of toughness of materials depend on an understanding of the characteristic instabilities of the crack tip, and their possible interactions. In this paper we examine the effect of dislocation emission on subsequent cleavage of a crack and on further dislocation emission. The work is an extension of the previously published Lattice Greens Function met

Anders B. Eriksson, Jari M. Kinaret, Lev V. Mikheev

We represent the slow, glassy equilibrium dynamics of a line in a two-dimensional random potential landscape as driven by an array of asymptotically independent two-state systems, or loops, fluctuating on all length scales. The assumption of independence enables a fairly complete analytic description. We obtain good agreement with Monte Carlo simulations whe

Enzo Granato, J. M. Kosterlitz, M. P. Nightingale

The critical behavior of frustrated Josephson-junction arrays at $f=1/2$ flux quantum per plaquette is considered. Results from Monte Carlo simulations and transfer matrix computations support the identification of the critical behavior of the square and triangular classical arrays and the one-dimensional quantum ladder with the universality class of the XY-

X. S. Ling, M. J. Higgins, Chao Tang, P. M. Chaikin

We study $I$-$V$ characteristics of periodic square Nb wire networks as a function of temperature in a transverse magnetic field, with a focus on three fillings 2/5, 1/2, and 0.618 that represent very different levels of incommensurability. For all three fillings, a scaling behavior of $I$-$V$ characteristics is found, suggesting a finite temperature continu

Koji Hukushima, Koji Nemoto

We propose an efficient Monte Carlo algorithm for simulating a ``hardly-relaxing" system, in which many replicas with different temperatures are simultaneously simulated and a virtual process exchanging configurations of these replica is introduced. This exchange process is expected to let the system at low temperatures escape from a local minimum. By us

Paul J. Green, Smita Mathur

Recent results from the ROSAT All-Sky Survey (RASS) have shown that broad absorption line (BAL) QSOs are either highly absorbed or underluminous in the soft X-ray bandpass. Here, we extend this work by analyzing all known bona fide BALQSOs observed within the inner 20' of the ROSAT PSPC. This sample includes both targeted and serendipitous exposures rang

D. S. Salopek

Recent advances in observational cosmology are changing the way we view the nature of time. In general relativity, the freedom in choosing a time hypersurface has hampered the implementation of the theory. Fortunately, Hamilton-Jacobi theory enables one to describe all time hypersurfaces on an equal footing. Using an expansion in powers of the spatial curvat

Xiangdong Shi

The proximity effect of metal line absorption systems in spectra of high redshift quasars and quasar pairs is investigated through the distribution of \Lyalpha forests. No strong proximity effect is found down to 500 km/sec away from a metal line absorption system for lyman $α$ clouds with $13.3\le\log\NHI <13.8$ at a redshift of $\sim 3$. Its implication on

Srdjan Samurovic, Vladan Celebonovic

Using simple physical reasoning we have estimated the wavelengths and line-widths of spectral lines arising from the decays of massive neutrinos. We have, also, to some extent, discussed the possible consequences of these decays in observable astrophysical settings. We have compared our conclusions with the predictions of the decaying dark matter (DDM) model

D. J. Burke, C. A. Collins, R. C. Nichol, A. K. Romer

We report on the progress of our search for serendipitous distant X-ray galaxy clusters in the ROSAT PSPC pointed observations archive. The initial aim of our work is to measure the X-ray luminosity function of clusters down to 4 x 10^-14 erg cm^-2 s^-1 and so test the claims of cluster evolution at moderate redshifts. We have R band images and spectroscopy

M. Arnould, N. Mowlavi, A. Champagne

The impact of nuclear physics uncertaintites on the abundances predicted to emerge from the cold CNO, NeNa and MgAl modes of hydrostatic hydrogen burning is discussed in the framework of a simple parametric model. In addition of being able to mimic qualitatively detailed stellar model predictions, these parametric calculations have the virtue of isolating in

S. Courteau, R. S. de Jong, A. H. Broeils

We combine deep optical and IR photometry for 326 spiral galaxies from two recent galaxy samples and report that the surface brightness profiles of late-type spirals are best fit by two exponentials. Moreover, the ratio of bulge and disk scale lengths takes on a restricted range of values and is uncorrelated with Hubble type. This suggests a scale-free Hubbl

P. Lundqvist, C. Fransson

The narrow emission lines from the inner ring around SN 1987A during the first $\sim 2000$ days are modeled. The analysis extends that in Lundqvist & Fransson (1991) to include an improved description for the geometry, a multi-density structure of the emitting gas, results from improved calculations for the evolu- tion of the EUV radiation from the outburst,

Martin G. Haehnelt

The large sizes of Lyman alpha ``clouds&#39;&#39; inferred from coincident absorption in the spectrum of close quasar pairs suggests that these are transient flattened structures of small overdensity. It is argued that the observed absorbers should be preferentially located in underdense regions of the universe and should typically expand faster than the Hub

Andrew Chen, Joseph Dwyer, Philip Kaaret

We present spectra of the inverse-Compton and extragalactic components of the high-energy gamma-radiation based on an analysis of the emission at high galactic latitudes ($\vert$b$\vert$ $\geq$ $30°$). We correlate the gamma-ray intensity with a model consisting of an isotropic component, a component proportional to the 408 MHz synchrotron radiation, and a c

Sergey Krivonos, Kris Thielemans

We describe a general purpose Mathematica package for computing Superfield Operator Product Expansions in meromorphic $N=2$ superconformal field theory. Given the SOPEs for a set of ``basic&#34; superfields, SOPEs of arbitrarily complicated composites can be computed automatically. Normal ordered products are always reduced to a standard form. It is possible

Hung Jung Lu, Joseph Milana

It is shown that direct photons provide a leading twist mechanism for diffractive jet production in which the jets carry away all of the momentum lost by the proton. Two-photon processes are thus expected to asymptotically dominate &#34;super-hard&#34; pomeron events in $ep$ collisions. We report the expected rates from these events for the recent ZEUS and H

Eugene Tyurin, Rikard von Unge

We formulate Poisson-Lie T-duality in a path-integral manner that allows us to analyze the quantum corrections. Using the path-integral, we rederive the most general form of a Poisson-Lie dualizeable background and the generalized Buscher transformation rules it has to satisfy.

K. Piotrzkowski

A measurement of the longitudinal polarization of the electron beam at HERA utilizing coherent interactions of high energy photons in crystals is proposed. Modification of existing facilities would allow an independent polarization measurement and a verification of birefringence phenomena in crystals for 20--30~GeV photons. Relevant experimental issues and s

R. A. Daly, E. J. Guerra, A. Guijosa

Two key results are presented in this paper. First, equipartition Doppler factors have been estimated for a sample of 105 sources with previously estimated inverse Compton Doppler factors. The different categories of active galactic nuclei (AGN) have different ranges and typical values of the Doppler factor; lobe dominated AGN tend to have low Doppler factor

Torsten Ekedahl

We introduce the notion of a variety (or more generally a motive) of CM-type which generalises the well known notion of abelian variety of CM-type. Just as in that particular case it will turn out that the cohomology of the variety is determined by purely combinatorial data; the type of the variety. As applications we will show that the ł-adic representation

V. Aldaya, J. Guerrero, G. Marmo

This talk is devoted mainly to the concept of higher-order polarization on a group, which is introduced in the framework of a Group Approach to Quantization, as a powerful tool to guarantee the irreducibility of quantizations and/or representations of Lie groups in those anomalous cases where the Kostant-Kirilov co-adjoint method or the Borel-Weyl-Bott repre

Y. Satoh

We study quantum aspects of the Einstein gravity with one time-like and one space-like Killing vector commuting with each other. The theory is formulated as a $\coset$ nonlinear $σ$-model coupled to gravity. The quantum analysis of the nonlinear $σ$-model part, which includes all the dynamical degrees of freedom, can be carried out in a parallel way to ordin

C. -H. Chen, M. Drees, J. F. Gunion

We explore the techniques, cross sections and expected signal significance for detecting invisible and almost invisible particles at LEP2 and the NLC by means of a hard photon tag. Examples from supersymmetry include the lightest chargino and second lightest neutralino when their masses are nearly the same as that of the lightest neutralino (the LSP), and in

S. E. Burkov, B. E. C. Koltenbah, L. W. Bruch

Quasiperiodic long range order is intermediate between spatial periodicity and disorder, and the excitations in 1D quasiperiodic systems are believed to be transitional between extended and localized. These ideas are tested with a numerical analysis of two incommensurate 1D elastic chains: Frenkel-Kontorova (FK) and Lennard-Jones (LJ). The ground state confi

Bai-Qi Jin, Shan-You Zhou

In this paper,we give the explicit formulae of vertex operators of ${U_q}(\widehat{B}_l)$ for level-one as operators on the Fock space. Meanwhile, we point out that the free field realization (by one fermionic field and $l$ bosonic fields) of highest weight module with highest weight $Λ_l$ has two irreducible modules.

George Svetlichny

The hilbert-space structure of quantum mechanics is related to the causal structure of space-time. The usual measurement hypotheses apparently preclude nonlinear or stochastic quantum evolution. By admitting a difference in the calculus of joint probabilities of events in space-time according to whether the separation is space-like or time-like, a relativist

Asher Peres

Experimental tests of Bell inequalities ought to take into account all detection events. If the latter are postselected, and only some of these events are included in the statistical analysis, a Bell inequality may be violated, even by purely classical correlations. The paradoxical properties of Werner states, recently pointed out by Popescu, can be explaine

S. Majid

We show that the affine quantum group $U_q(\hat{sl_2})$ is isomorphic to a bicrossproduct central extension $C Z{}_χ\cross U_q(Lsl_2)$ of the quantum loop group $U_q(Lsl_2)$ by a quantum cocycle $χ$, which we construct. We prove the same result for $U_q(\hat{g})$ in R-matrix form.

S. Majid

We write the fermionic $q$-Fock space representation of $U_q(\hat{sl_n})$ as an infinite extended braided tensor product of finite-dimensional fermionic $U_q(sl_n)$-quantum planes or exterior algebras. Using braided geometrical techniques developed for such quantum exterior algebras, we provide a new approach to the Kashiwara-Miwa-Stern action of the Heisenb

Mischa Cotlar, Cora Sadosky

In this paper we show that the theory of Hankel operators in the torus $\T^d$, for $d > 1$, presents striking differences with that on the circle $\T$, starting with bounded Hankel operators with no bounded symbols. Such differences are circumvented here by replacing the space of symbols $L^\infty (\T)$ by BMOr$(\T^d)$, a subspace of product BMO, and the sin

Menachem Kojman

This is a survey paper of Shelah&#39;s pcf theory. In this part the theory is developed up to the pcf theorem.

Satish D. Joglekar, Bhabani Prasad Mandal

We consider a certain local generalization of BRS transformations of Yang-Mills theory in which the anti-commuting parameter is space time dependent. While these are not exact symmetries, they do lead to a new nontrivial WT identity. We make a precise connection between the ``local BRS &#34;and the broken orthosymplectic symmetry recently found in superspace

Dimitri Polyakov

We analyze the interaction between the massless RR states with a dilaton in a type IIB superstring. By constructing vertex operators for massless and massive RR states and computing their correlation functions with a dilaton we find the Ramond-Ramond part of the superstring low-energy effective action. The RR terms appearing in the action do not contain the

Laurent Baulieu

We investigate the properties of 2-D gravity in the Batalin and Vilkovisky quantization scheme. We find a factorized structure which exhibits duality properties analogous to those existing in the topological theories of forms. New conformal field are introduced with their invariant action.

Laurent Baulieu

We construct a framework which unifyies in dual pairs the fields and anti-fields of the Batalin and Vilkovisky quantization method. We consider gauge theories of p-forms coupled to Yang-Mills fields. Our algorithm generates many topological models of the Chern-Simon type or of the Donaldson-Witten type. Some of these models can undergo a partial breaking of

M. Berkooz

We match a few non chiral operators in the electric and magnetic descriptions of SQCD, suggesting the first evidence of electric-magnetic duality outside the chiral ring. Algebraically, these non chiral operators are a module of the chiral ring. Physically, the suggested correspondence essentially transforms certain electric gauge invariant composites contai

H. Dorn

It is shown that for 2D field theories only the first order coefficient of the gravitationally dressed RG $β$-function is scheme independent. This is valid even for matter theories with one dimensionless coupling, where the first two coefficients of the original $β$-function are scheme independent.

Omduth Coceal, Steven Thomas

Following the previous work of Ferretti and Yang on the role of magnetic fields in the theory of conformal turbulence, we show that non-unitary minimal model solutions to 2-dimensional magnetohydrodynamics (MHD) obtained by dimensional reduction from 3-dimensions exist under different (and more restrictive) conditions. From a 3-dimensional point of view, the

Pei Wang

Using the Mathai-Quillen formalism we reexamine the twisted N=4 supersymmetric model of Vafa-Witten theory. Smooth out the relation between the supersymmetric action and the path integral representation of the Thom class.

Tomohiko Takahashi

Considering the conformal anomaly in an effective action, the critical dimension of string theory can be decided in the harmonic gauge, in which it had been reported before to be indefinite. In this gauge, there is no anomaly for the ghost number symmetry. This can be naturally understood in terms of Faddeev-Popov conjugation in the theory.

H. Lu, C. N. Pope

In this paper, we give a construction of $p$-brane solitons in all maximal supergravity theories in $4\le D \le 11$ dimensions that are obtainable from $D=11$ supergravity by dimensional reduction. We first obtain the full bosonic Lagrangians for all these theories in a formalism adapted to the $p$-brane soliton construction. The solutions that we consider i

Chi-Keung Chow, Tung-Mow Yan

In the conventional approach to the $1/N_c$ expansion, electroweak interactions are switched off and large $N_c$ QCD is treated in isolation. We study the self-consistency of taking the large $N_c$ limit in the presence of electroweak interaction. If the electroweak coupling constants are held constant, the large $N_c$ counting rules are violated by processe

Chi-Keung Chow, Dan Pirjol

We derive two model-independent sum rules relating the transition matrix elements for radiative and strong decays of excited heavy mesons to properties of the lowest-lying heavy mesons. The sum rule for the radiative decays is an analog of the Cabibbo-Radicati sum rule and expresses the sum of the radiative widths in terms of the isovector charge radius of t

William H. Kinney, K. T. Mahanthappa

Models of inflationary cosmology based on spontaneous symmetry breaking typically suffer from the shortcoming that the symmetry breaking scale is driven to nearly the Planck scale by observational constraints. In this paper we investigate inflationary potentials in a general context, and show that this difficulty is characteristic only of potentials $V(ϕ)$ d

Gautam Bhattacharyya, Gustavo C. Branco, Wei-Shu Hou

The experimental values of $R_b$ and $R_c$ are the only data which do not seem to agree with Standard Model predictions. Although it is still premature to draw any definite conclusions, it is timely to look for new physics which could explain the excess in $R_b$ and deficit in $R_c$. We investigate this problem in a simple extension of the Standard Model, wh

X. Artru

The specificities of transverse polarization with respect to helicity of ultrarelativistic fermions are pointed out. For massless fermions, a covariant transversity four-vector is defined, up to a kind of gauge transformation. The tranversity distribution of quarks in a nucleon is defined. Its possible connection to the magnetic or electric dipole moment of

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

The neutrinoless double beta decay ($\znbb$) induced by light Majorana neutrino exchange between decaying nucleons, accompanied by the squark exchange inside one nucleon, recently discussed by Babu and Mohapatra, is carefully analyzed both from the particle and nuclear physics sides. New nuclear matrix elements relevant to this mechanism are calculated. We e

B. Ziaja

We investigate the origin of intermittency for multiparticle distribution in momentum space, following the idea that there is a kind of power law distribution of the space-time region of hadron emission. Using the formalism of current ensamble model to describe boson sources we discuss intermittency exponents for the coherent and incoherent ( chaotic) partic

N. E. Tyurin

We discuss some of the issues to be accounted under conducting spin physics program at RHIC.

V. Bernard, N. Kaiser, Ulf-G. Meißner

We analyze the new threshold data for neutral pion photoproduction off protons in the framework of heavy baryon chiral perturbation theory. We show that large loop corrections are needed to understand the S--wave multipole $E_{0+}$ and that all pertinent low--energy constants can be understood within the framework of resonance exchange saturation. Previous i

R Delbourgo, Dongsheng Liu

It is possible to express all the strong and electromagnetic interactions of ground state hadrons in terms of a single coupling constant and the constituent quark masses, using spin-flavour relativistic supermultiplet theory. Results are generally accurate to within 10%.

Marco A. Diaz, Tonnis A. ter Veldhuis, Thomas J. Weiler

Vacuum stability and metastability imply lower limits on the mass of the higgs boson in the Standard Model (SM). In contrast, we present an improved calculation of an upper limit on the lightest higgs mass in supersymmetric (susy) models, by summing to all orders in perturbation theory the leading and next--to--leading logarithms with a renormalization group

Karl Jansen, Chuan Liu, Martin Luescher, Hubert Simma

A general strategy to solve the non-perturbative renormalization problem in lattice QCD, using finite-size techniques and numerical simulations, is described. As an illustration we discuss the computation of the axial current normalization constant, the running coupling at zero quark masses and the scale evolution of the renormalized axial density. The non-p

Jorge Griego

Some features of extended loops are considered. In particular, the behaviour under diffeomorphism transformations of the wavefunctions with support on the extended loop space are studied. The basis of a method to obtain analytical expressions of diffeomorphism invariants via extended loops are settled. Applications to knot theory and quantum gravity are cons

H. P. de Oliveira, E. S. Cheb-Terrab, DFT-UERJ, Brazil

A massless scalar field minimally coupled to the gravitational field in a simplified spherical symmetry is discussed. It is shown that, in this case, the solution found by Roberts, describing a scalar field collapse, is in fact the most general one. Taking that solution as departure point, a study of the gravitational collapse for the self-similar conformal

Gregory B. Cook, Stuart L. Shapiro, Saul A. Teukolsky

Solving dynamical problems in general relativity requires the full machinery of numerical relativity. Wilson has proposed a simpler but approximate scheme for systems near equilibrium, like binary neutron stars. We test the scheme on isolated, rapidly rotating, relativistic stars. Since these objects are in equilibrium, it is crucial that the approximation w

T. Arleigh Crawford

We study the topology of the space of harmonic maps from $S^2$ to \CP 2$. We prove that the subspaces consisting of maps of a fixed degree and energy are path connected. By a result of Guest and Ohnita it follows that the same is true for the space of harmonic maps to $\CP n$ for $n\geq 2$. We show that the components of maps to $\CP 2$ are complex manifolds

Yuli Lyanda-Geller, Paul M. Goldbart, Daniel Loss

Quantization of superflow-circulation and of magnetic-flux are considered for systems, such as superfluid $^3$He-A and unconventional superconductors, having nonscalar order parameters. The circulation is shown to be the anholonomy in the parallel transport of the order parameter. For multiply-connected samples free of distributed vorticity, circulation and

D. Zanchi, A. Bjeliš, G. Montambaux

The influence of an external magnetic field on a quasi one-dimensional system with a charge density wave (CDW) instability is treated within the random phase approximation which includes both CDW and spin density wave correlations. We show that the CDW is sensitive to both orbital and Pauli effects of the field. In the case of perfect nesting, the critical t

Marcelo Gleiser, Andrew F. Heckler, Edward W. Kolb

We consider the nonequilibrium dynamics of a a real scalar field in a degenerate double-well potential. The system is prepared in the lowest free energy state in one of the wells and the dynamics is driven by the coupling of the field to a thermal bath. Using a simple analytical model, based on the subcritical bubbles method, we compute the fraction of the t

A. Martin-Rodero, A. Levy Yeyati, F. J. Garcia-Vidal

We present a theory for the frequency-dependent current fluctuations in superconducting quantum point-contacts (SQPC) within the dc transport regime. This theory is valid for any barrier transparency between the tunnel and ballistic limits, yielding an analytical expression for the fluctuations spectrum in the subgap region. It is shown that the level of noi

G. G. Batrouni, S. Dippel, L. Samson

Experiments on the motion of a particle on an inclined rough plane have yielded some surprising results. For example, it was found that the frictional force acting on the ball is viscous, {\it i.e.} proportional to the velocity rather than the expected square of the velocity. It was also found that, for a given inclination of the plane, the velocity of the b

J. A. Nieminen

A mean field method to study heteroepitaxial thin film growth is applied to growth, intermixing and surface reconstructions of $Au$ on $Ag(110)$. The results are in accordance with experimentally observed ``burrowing&#39;&#39; at submonolayer coverages and growth of elongated, $(1 \times 3)$ reconstructed, $Au$ clusters at higher coverages. At coverages of f

H. C. Jongert, M. van der Klis

We report a search for pulsations in 147 Type 1 X-ray bursts observed with EXOSAT in 10 X-ray burst sources. Instead of treating each burst separately, we incoherently averaged the power spectra of all of the bursts of a given burster to improve statistics. No periodicities were detected; 99% confidence upper limits on the modulation depths of possible perio

Scott Dodelson

Separating foregrounds from the signal is one of the big challenges in cosmic microwave background (CMB) experiments. A simple way to estimate the CMB temperature in a given pixel is to fit for the amplitudes of the CMB and the various foreground components. The variance squared of this estimator is shown to be equal to $[(FDF)^2\ \sigzt + \sigsh^2]$, where

Michael A. Nowak, Brian A. Vaughan

The ``low&#39;&#39; (hard or ``non-thermal&#39;&#39;) state of black hole candidates is sometimes modelled via an optically thick, hot Compton cloud that obscures a softer input source such as an accretion disk. In these models the observed output spectra consist entirely of photons reprocessed by the cloud, making it difficult to extract information about t

P. J. Armitage, C. J. Clarke

We construct models for the rotation rates of T Tauri stars whose spin is regulated by magnetic linkage between the star and a surrounding accretion disc. Our models utilise a time-dependent disc code to follow the accretion process and include the effects of pre-main-sequence stellar evolution. We find that the initial disc mass controls the evolution of th

Benjamin J. Weiner, T. B. Williams

We have detected faint, diffuse H$αemission from several points along the Magellanic Stream, using the Rutgers Fabry--Perot Interferometer at the CTIO 1.5-m telescope. At points on the leading edges of the H I clouds MS II, MS III, and MS IV, we detect H$αemission of surface brightness $0.37 \pm 0.02$ Rayleighs, $0.21 \pm 0.04$ R, and $0.20 \pm 0.02$ R respe