December 1995 arXiv papers — page 4

S. Pratik Khastgir, Ryu Sasaki

The equation of motion of affine Toda field theory is a coupled equation for $r$ fields, $r$ is the rank of the underlying Lie algebra. Most of the theories admit reduction, in which the equation is satisfied by fewer than $r$ fields. The reductions in the existing literature are achieved by identifying (folding) the points in the Dynkin diagrams which are c

Zurab Kakushadze, S. -H. Henry Tye

The present status of superstring phenomenology is briefly discussed.

Dmitri Diakonov, Hilmar Forkel, Matthias Lutz

The generation of gauge--dependent fermion vacuum condensates in Yang--Mills theory would dynamically break the gauge symmetry and thus provide an alternative to the Higgs mechanism in unified theories. We explore a simple example: instanton-induced quark pair (diquark) condensation in QCD with 2 flavors and $N_c$ colors. We do find diquark condensates in th

T. Schaefer, E. V. Shuryak

We study hadronic correlation functions in the interacting instanton liquid model, both at zero and nonzero temperature $T$. At zero $T$ we investigate the dependence of the correlators on the instanton ensemble, in particular the effect of the fermionic determinant. We demonstrate that quark-induced correlations between instantons are important, especially

Howard Baer, Chih-hao Chen, Frank Paige, Xerxes Tata

We use ISAJET to perform a detailed study of the multilepton signals expected from cascade decays of supersymmetric particle produced at the CERN LHC. Our analysis is performed within the framework of the minimal supergravity model with gauge coupling unification and radiative electroweak symmetry breaking. We delineate the regions of parameter space where j

H. J. Weber, Xiaoming Xu

A constituent quark model is developed for an arbitrary light- cone direction ω. Form factors are obtained from free one-body electromagnetic current matrix elements. They are found to be ω- independent for spin-0 mesons, the nucleon and Λhyperon, while there is ω-dependence for spin-1 systems like the deuteron.

M. Anselmino, M. Boglione, J. Hansson, F. Murgia

We discuss the production of hadrons in polarized lepton nucleon interactions and in the current jet fragmentation region; using the QCD hard scattering formalism we compute the helicity density matrix of the hadron and show how its elements, when measurable, can give information on the spin structure of the nucleon and the spin dependence of the quark fragm

J. N. Bahcall, P. I. Krastev

Assuming neutrino oscillations occur, the pp electron neutrino flux is uncertain by at least a factor of two, the ${\rm ^8B}$ flux by a factor of five, and the ${\rm ^7Be}$ flux by a factor of forty-five. Calculations of the expected results of future solar neutrino experiments (SuperKamiokande, SNO, BOREXINO, ICARUS, HELLAZ, and HERON) are used to illustrat

A. V. Belitsky, A. V. Efremov, O. V. Teryaev

We consider the twist-3 gluon contribution to the transverse spin structure function $g_2$.We find that the Burkhardt-Cottingham sum rule is satisfied. The additional {\it nonlocal} operators appear in the moments of g2 which were absent in previous analysis of Bukhvostov, Kuraev and Lipatov.

Yusuke Taniguchi, Yuhsuke Yoshida

The chiral symmetry of QCD is studied at finite temperature and chemical potential using the Schwinger-Dyson equation in the improved ladder approximation. We calculate three order parameters; the vacuum expectation value of the quark bilinear operator, the pion decay constant and the quark mass gap. We have a second order phase transition at the temperature

Johan Bijnens, Ansar Fayyazuddin, Joaquim Prades

We calculate within the Extended Nambu--Jona-Lasinio model the leading in $1/N_c$ contribution to $γγ\toπ^0π^0$ to all orders in the external momenta and quark masses. This result is then combined with the known two-loop Chiral Perturbation Theory and compared with the data and other calculations. A technical difficulty in the same calculation beyond order $

Leif Lonnblad

The success of recently proposed models for describing rapidity-gap events in DIS at HERA, in terms additional colour exchange between the struck system and the proton remnant in boson-gluon fusion events, are found to rely heavily on the absence or artificial suppression of perturbative gluon emission in the forward region. A model without such suppression

H. -G. Kohrs

We investigate the effect of a direct pomeron coupling to quarks on inclusive jet production in DIS and photoproduction. The direct pomeron coupling generates a point-like contribution to the diffractive part of the structure function $F_2$, which is analysed on the basis of the latest H1 and ZEUS data. Our model assumptions for the pomeron structure are con

Leif Lonnblad, Mike Seymour, Edouard Boudinov, Jon Butterworth

The report from the working group on 'γγEvent Generators' of the LEP 2 workshop

N. A. Sveshnikov, F. V. Tkachov

We discuss quantum-field-theoretic interpretation of the family of observables (the so-called C-algebra) introduced in [ F.V.Tkachov: Preprint FERMILAB-PUB-95/191-T] for a systematic description of multijet structure of multiparticle final states at high energies. We argue that from the point of view of general quantum field theory, all information about the

M. Kawasaki, Naoshi Sugiyama, T. Yanagida

In the chaotic inflation models, quantum fluctuations for axion fields lead to the overproduction of domain walls and too large isocurvature fluctuations which is inconsistent with the observations of cosmic microwave background anisotropies. These problems are solved by assuming a very flat potential for the Peccei-Quinn scalar. As the simplest possibility,

S. J. Brodsky, G. T. Gabadadze, A. L. Kataev, H. J. Lu

We use the BLM scale-fixing prescription to derive a renormalization-scheme invariant relation between the coefficient function for the Bjorken sum rule for polarized deep inelastic scattering and the $R$-ratio for the $e^+e^-$ annihilation cross section. This relation provides a generalization of the Crewther relation to non-conformally invariant gauge theo

F. Franke, H. Fraas

The purpose of this paper is to present a complete and consistent list of the Feynman rules for the vertices of neutralinos and Higgs bosons in the Next-To-Minimal Supersymmetric Standard Model (NMSSM), which does not yet exist in the literature. The Feynman rules are derived from the full expression for the Lagrangian and the mass matrices of the neutralino

R. Rattazzi, U. Sarid

We discuss some fundamental concerns regarding the recent proposal of Dimopoulos and Giudice for dynamically aligning the soft masses of the sfermions in the minimal supersymmetric standard model (MSSM) with the corresponding fermion masses to suppress flavor changing neutral currents. We show that the phenomenologically-favored presence of right-handed neut

Daniel Mueller

In this letter we propose a semi-analitical method of evaluation of the power spectrum of a circular moving Unruh-type detector using the method of residue and compare the spectrum with the already known result in the relativistic limit.

S. N. Vergeles

In this paper the quantization of the 2$+$1-dimensional gravity couplet to the massless Dirac field is carried out. The problem is solved by the application of the new Dynamic Quantization Method [1,2]. It is well-known that in general covariant theories such as gravitation, a Hamiltonian is any linear combination of the first class constraints, which can be

Bernd Bruegmann

Although an important issue in canonical quantization, the problem of representing the constraint algebra in the loop representation of quantum gravity has received little attention. The only explicit computation was performed by Gambini, Garat and Pullin for a formal point-splitting regularization of the diffeomorphism and Hamiltonian constraints. It is sho

William Arveson

It is known that every semigroup of normal completely positive maps of a von Neumann can be ``dilated" in a particular way to an E_0-semigroup acting on a larger von Neumann algebra. The E_0-semigroup is not uniquely determined by the completely positive semigroup; however, it is unique (up to conjugacy) provided that certain conditions of {\it minimalit

C. A. Hayward, D. Poilblanc, D. J. Scalapino

The optical conductivity $σ(ω)$ of a doped two-leg t--J ladder is calculated for an electric field polarized parallel to the legs of the ladder. The conductivity has a Drude weight proportional to the hole doping and an apparent threshold for absorption (a pseudo gap) which may be associated with the energy to break a pair. This pseudogap in $σ(ω)$ is presen

P. Ray, G. Date

The geometry of fracture patterns in a dilute elastic network is explored using molecular dynamics simulation. The network in two dimensions is subjected to a uniform strain which drives the fracture to develop by the growth and coalescence of the vacancy clusters in the network. For strong dilution, it has been shown earlier that there exists a characterist

Michael S. Turner, Yun Wang

Inflation gives rise to a nearly scale-invariant spectrum of tensor perturbations (gravitational waves), their contribution to the Cosmic Background Radiation (CBR) anisotropy depends upon the present cosmological parameters as well as inflationary parameters. The analysis of a sampling-variance-limited CBR map offers the most promising means of detecting te

S. Schindler, J. Wambsganss

We present results and an analysis of a ROSAT PSPC pointed observation of the galaxy cluster CL0939+472. This very rich and very distant cluster is known to contain an unusually high fraction of blue and E+A galaxies, and a lot of merging of galaxies is going on. The X-ray properties we find are also quite unusual. The luminosity in the ROSAT band (0.1-2.4 k

M. Pohl, W. Reich, T. P. Krichbaum, K. Standke

We report multifrequency observations of the $γ$-ray blazar 0528+134 with the Effelsberg 100-m telescope, the IRAM 30-m telescope, and the NRL Green Bank Interferometer. 0528+134 underwent a major radio and mm outburst in 1993 a few month after a very strong outburst in high energy $γ$-rays. A similar behaviour is indicated for the weaker $γ$-ray outburst in

Colin A. Norman, Robert Braun

We discuss the current observational and theoretical issues concerning cold gas at high redshift and present simulations showing how a number of observational issues can be resolved with planned future instrumentation.

Arnold I. Boothroyd, Robert A. Malaney

Observations of stellar CNO isotope ratios indicate the presence of additional mixing processes on the red giant branch. An estimate of the resulting stellar He-3 depletion is made, as a function of stellar mass and metallicity. Based on stellar nucleosynthesis and galactic chemical evolution calculations, we determine the degree to which the destruction of

Laurent Bonavero

The central topic of this thesis is the study of some properties of a class of complex compact manifolds~: Moishezon manifolds. In the first part, we generalize J.-P. Demailly's holomorphic Morse inequalities to the case of a line bundle equipped with a metric with analytic singularities on an arbitrary compact complex manifold. Our inequalities give an

Giuseppe Tormen, Edmund Bertschinger

We present a new method to add long wavelength power to an evolved $N$-body simulation, making use of the Zel'dovich (1970) approximation to change positions and velocities of particles. We describe the theoretical framework of our technique and apply it to a P$^3$M cosmological simulation performed on a cube of $100$ Mpc on a side, obtaining a new ``sim

S. Bertolini, J. O. Eeg, M. Fabbrichesi

We discuss direct $CP$ violation in the standard model by giving a new estimate of $\varepsilon'/\varepsilon$ in kaon decays. Our analysis is based on the evaluation of the hadronic matrix elements of the \mbox{$ΔS =1$} effective quark lagrangian by means of the chiral quark model, with the inclusion of meson one-loop renormalization and NLO Wilson coeff

Vijay Balasubramanian, Herman Verlinde

We study radiation from black holes in the effective theory produced by integrating gravity and the dilaton out of $1+1$ dilaton gravity. The semiclassical wavefunctions for the dressed particles show that the self-interactions produce an unusual renormalization of the frequencies of outgoing states. Modes propagating in the dynamical background of an incomi

N. J. Cerf, C. Adami

A framework for a quantum mechanical information theory is introduced that is based entirely on density operators, and gives rise to a unified description of classical correlation and quantum entanglement. Unlike in classical (Shannon) information theory, quantum (von Neumann) conditional entropies can be negative when considering quantum entangled systems,

Douglas M. Snyder

Generally a central role has been assigned to an unavoidable physical interaction between the measuring instrument and the physical entity measured in the change in the wave function that often occurs in measurement in quantum mechanics. A survey of textbooks on quantum mechanics by authors such as Dicke and Witke (1960), Eisberg and Resnick (1985), Gasiorow

Jean Avan, Antal Jevicki

We construct collective field theories associated with one-matrix plus $r$ vector models. Such field theories describe the continuum limit of spin Calogero Moser models. The invariant collective fields consist of a scalar density coupled to a set of fields in the adjoint representation of $U(r)$. Hermiticity conditions for the general quadratic Hamiltonians

M. D'Agostino, A. S. Botvina, P. M. Milazzo, M. Bruno

Multifragment disintegrations, measured for central Au + Au collisions at E/A = 35 MeV, are analyzed with the Statistical Multifragmentation Model. Charge distributions, mean fragment energies, and two-fragment correlation functions are well reproduced by the statistical breakup of a large, diluted and thermalized system slightly above the multifragmentation

Antoine Van Proeyen

An introduction to $N=2$ rigid and local supersymmetry is given. The construction of the actions of vector multiplets is reviewed, defining special Kähler manifolds. Symplectic transformations lead to either isometries or symplectic reparametrizations. Writing down a symplectic formulation of special geometry clarifies the relation to the moduli spaces of a

David Kutasov

We propose a conformal field theory description of a solitonic heterotic string in type $IIA$ superstring theory compactified on $K3$, generalizing previous work by J. Harvey, A. Strominger and A. Sen. In ten dimensions the construction gives a fivebrane which is related to the fundamental type $II$ string by electric -- magnetic duality, and to the Dirichle

H. Suganuma, K. Itakura, H. Toki

Correlation between instantons and QCD-monopoles is studied in the abelian-gauge-fixed QCD. From a simple topological consideration, instantons are expected to appear only around the QCD-monopole trajectory in the abelian-dominating system. The QCD-monopole in the multi-instanton solution is studied in the Polyakov-like gauge, where $A_4(x)$ is diagonalized.

H. Suganuma, K. Itakura, H. Toki, O. Miyamura

The correlation between instantons and QCD-monopoles is studied both in the lattice gauge theory and in the continuum theory. From a simple topological consideration, instantons are expected to live only around the QCD-monopole trajectory in the abelian gauge. First, the instanton solution is analytically studied in the Polyakov-like gauge, where $A_4(x)$ is

I. -Juliana Sackmann, Arnold I. Boothroyd

It has been demonstrated that Li-7 can be created in low mass red giant stars, via the Cameron-Fowler mechanism, due to extra deep mixing and the associated "cool bottom processing" (CBP). Under certain conditions, this Li-7 creation can take the place of the Li-7 destruction normally expected. Note that such extra mixing on the red giant branch (RGB

N. Dupuis

We suggest that highly conducting oriented polymers with a fibril structure can be modeled by a regular lattice of disordered metallic wires with a random first-neighbor interwire coupling which mimics the cross-links between fibrils. We show that such a model can be described by a non-linear sigma model. Within a one-loop self-consistent approximation, we d

Stephan Narison

New double ratios of exponential moments of different two-point functions, which are less sensitive to the heavy quark mass and to the continuum effects than the commonly used ratio of moments, are presented for a more refined analysis of the mass-splittings between the different heavy quarkonia states. We show that at the $c$ and $b$ quark mass scales the $

Arnold I. Boothroyd, I. -Juliana Sackmann

It is demonstrated that deep circulation mixing below the base of the standard convective envelope, and the consequent "cool bottom processing" (CBP) of the CNO isotopes, can reproduce the trend with stellar mass of the C-12/C-13 observations in low mass red giants. (This trend is opposite to what is expected from standard first dredge-up.) Our model

G. Bilalbegovic

The morphology of epitaxial structures formed in solidification of liquid Au films on the Au(110) surface was studied by molecular dynamics simulation based on a many--body interatomic potential. The (1x2) reconstructed and smooth phase at the temperature T=500 K, as well as a deconstructed and rough phase of the Au(110) substrate at T=900 K, were investigat

V. Gurarie, A. Migdal

The instanton solution for the forced Burgers equation is found. This solution describes the exponential tail of the probability distribution function of velocity differences in the region where shock waves are absent. The results agree with the one found recently by Polyakov, who used the operator product conjecture. If this conjecture is true, then our WKB

P. Amore, M. B. Barbaro, A. De Pace

We discuss the description of a many-body nuclear system using Hamiltonians that contain the nucleon relativistic kinetic energy and potentials with relativistic corrections. Through the Foldy-Wouthuysen transformation, the field theoretical problem of interacting nucleons and mesons is mapped to an equivalent one in terms of relativistic potentials, which a

C. Beck, A. Szanto de Toledo

Global macroscopic features observed in the fully-damped binary processes in light di-nuclear systems, such as limiting angular momenta, mean total kinetic energies and energy thresholds for fusion-fission processes (''fission thresholds") are presented. Their deduced systematics are consistent with that obtained for heavier systems and follow a

Michael J. Mehl

Mercury has perhaps the strangest behavior of any of the metals. Although the other metals in column IIB have an $hcp$ ground state, mercury's ground state is the body centered tetragonal $β$Hg phase. The most common phase of mercury is the rhombohedral $α$Hg phase, which is stable from 79K to the melting point and meta-stable below 79K. Another rhombohe

Shalosh B. Ekhad, Doron Zeilberger

We prove an explicit formula for the number of $n \times n$ upper triangular matrices, over $GF(q)$, whose square is the zero matrix. This formula was recently conjectured by Sasha Kirillov and Anna Melnikov[KM].

Spiros A. Argyros, S. Merkourakis, A. Tsarpalias

It is proved that every normalized weakly null \sq\ has a sub\sq\ which is convexly unconditional. Further, an Hierarchy of summability methods is introduced and with this we give a complete classification of the complexity of weakly null \sq s.

H. Lu, C. N. Pope

In a previous paper \cite{lp}, supersymmetric $p$-brane solutions involving one dilatonic scalar field in maximal supergravity theories were classified. Although these solutions involve a number of participating field strengths, they are all equal and thus they carry equal electric or magnetic charges. In this paper, we generalise all these solutions to mult

K. Behrndt, E. Bergshoeff, Bert Janssen

We discuss the different discrete duality symmetries in six dimensions that act within and between (i) the 10-dimensional heterotic string compactified on $T^4$, (ii) the 10-dimensional Type IIA string compactified on $K3$ and (iii) the 10-dimensional Type IIB string compactified on $K3$. In particular we show that the underlying group-theoretical structure

Y. S. Kim

Wigner's 1939 paper on representations of the inhomogeneous Lorentz group is one of the most fundamental papers in physics. Wigner maintained his passion for this subject throughout his life. In this report, I will review the papers which he published with me on this subject. These papers deal with the question of unifying the internal space-time symmetr

Michele Bourdeau

In this letter we study supersymmetric sigma models on toric varieties. These manifolds are generalizations of CP^n manifolds. We examine here sigma models, viewed as gauged linear sigma models, on one of the simplest such manifold, the blow-up of P^2_(2,1,1), and determine their properties using the techniques of topological- antitopological fusion. We find

Rafael Ferraro, Claudio Simeone

It is well known that --differing from ordinary gauge systems-- canonical gauges are not admissible in the path integral for parametrized systems. This is the case for the relativistic particle and gravitation. However, a time dependent canonical transformation can turn a parametrized system into an ordinary gauge system. It is shown how to build a canonical

R. Shaisultanov

Using the Schwinger-Keldysh (closed time path or CTP) and Feynman-Vernon influence functional formalisms we obtain an expression for the influence functional in terms of Bogoliubov coefficients for the case of spinor quantum electrodynamics. Then we derive a CTP effective action in semiclassical approximation and its cumulant expansion. Using it we obtain a

P. Claus, B. de Wit, M. Faux, B. Kleijn

The vector-tensor multiplet is coupled off-shell to an N=2 vector multiplet such that its central charge transformations are realized locally. A gauged central charge is a necessary prerequisite for a coupling to supergravity and the strategy underlying our construction uses the potential for such a coupling as a guiding principle. The results for the action

R. Shaisultanov

Strassler's formulation of the string-derived Bern-Kosower formalism is extended to consider QED processes in homogeneous constant external field. A compact expression for the contribution of the one-loop with arbitrary number of external photon lines is given for scalar QED. Extension to spinor QED is shortly discussed.

S. Elitzur, A. Forge, A. Giveon, E. Rabinovici

We summarize some results in 4d, N=1 supersymmetric SU(2) gauge theories: the exact effective superpotentials, the vacuum structure, and the exact effective Abelian couplings for arbitrary bare masses and Yukawa couplings.

Bruce Hunt, Rolf Schimmrigk

We show that certain classes of K3 fibered Calabi-Yau manifolds derive from orbifolds of global products of K3 surfaces and particular types of curves. This observation explains why the gauge groups of the heterotic duals are determined by the structure of a single K3 surface and provides the dual heterotic picture of conifold transitions between K3 fibratio

Raj Gandhi, Chris Quigg, Mary Hall Reno, Ina Sarcevic

Cross sections for the interactions of ultrahigh-energy neutrinos with nucleons are evaluated in light of new information about nucleon structure functions. For $10^{20}$--eV neutrinos, the cross section is about 2.4 times previous estimates. We also review the cross sections for neutrino interactions with atomic electrons. Some consequences for interaction

Oscar J. P. Eboli, F. de Campos, J. Rosiek, J. W. F. Valle

We study the potential of LEP II to unravel the existence of invisibly decaying Higgs bosons through the reaction $e^+ e^- \rightarrow b\bar{b} + \ptmis$. We perform our analyses in a model independent way and our results show that LEP II is capable of discovering such a Higgs for a wide range of masses and couplings.

Manuel Drees, Tao Han

We compute cross sections for events where two pairs of partons scatter off each other in the same $γγ$ reaction, giving rise to at least 3 high--{\mbox{$p_T^{}$}} jets. Unlike in {\mbox{$p \bar p$}}\ collisions we find the signal to lie well above the background from higher order QCD processes. If the usual ``eikonaliztion" assumption is correct, the si

B. de Carlos, J. A. Casas, J. M. Moreno

In the absence of any additional assumption it is natural to conjecture that sizeable flavour-mixing mass entries, $Δm^2$, may appear in the mass matrices of the scalars of the MSSM, i.e. $Δm^2\sim O(m^2)$. This flavour violation can still be reconciled with the experiment if the gaugino mass, $M_{1/2}$, is large enough to yield (through the renormalization

J. A. Casas

Although the possible existence of dangerous charge and color breaking (CCB) directions in the MSSM has been known since the early 80's, only particular directions in the field-space have been considered, thus obtaining necessary but not sufficient conditions to avoid dangerous CCB minima. Furthermore, the radiative corrections to the potential were not

Michael S. Chanowitz

A method to embed models of strong $WW$ scattering in unitary gauge amplitudes is presented that eliminates the need for the effective $W$ approximation (EWA) in the computation of cross sections at high energy colliders.The cross sections obtained from the U-gauge amplitudes include the distributions of the final state fermions in $ff \rightarrow ffWW$, whi

A. N. Kamal

We discuss the role of nonfactorized contributions in $B \rightarrow ψ+ {K}^{*} $ and charmed meson decays. We demonstrate, using $ {D}^{+}_{S} \rightarrow ϕπ$ as a model, how nonfactorization, annihilation and final state interactions can be built into effective and unitarized $ {a}_{1} $ and $ {a}_{2} $.

Wolfgang Kilian, Michael Krämer, Peter M. Zerwas

Higgs-strahlung $e^+e^-\to ZH$ and $WW$ fusion $e^+e^-\to\barν_eν_e H$ are the most important mechanisms for the production of Higgs bosons in $e^+e^-$ collisions at LEP2 and future $e^+e^-$ linear colliders. We have calculated the cross sections and energy/angular distributions of the Higgs boson for these production mechanisms. When the $Z$ boson decays in

S. M. Bilenky, A. Bottino, C. Giunti, C. W. Kim

We have analyzed the results of reactor and accelerator neutrino oscillation experiments in a model with mixing of three neutrino fields and a neutrino mass hierarchy. It is shown that $ ν_μ\leftrightarrows ν_e $ oscillations with $ 0.6 \le Δm^2 \le 100 \, \mathrm{eV}^2 $ and amplitude larger than $ 2 \times 10^{-3} $ are not compatible with the existing lim

V. N. Gribov

The contribution of interactions at short and large distances to particle masses is discussed in the framework of the standard model.

Hyun-Chul Kim, M. V. Polyakov, K. Goeke

We investigate the singlet $g_T^{(0)}$ and isovector $g_T^{(3)}$ tensor charges of the nucleon, which are deeply related to the first moment of the leading twist transversity quark distribution $h_1(x)$, in the chiral quark-soliton model. With rotational $O(1/N_c) $ corrections taken into account, we obtain $g_T^{(0)}=0.69$ and $g_T^{(3)}=1.45$ at a low norm

Hyun-Chul Kim, A. Blotz, M. V. Polyakov, K. Goeke

The electromagnetic properties of the SU(3) octet baryons are investigated in the semibosonized SU(3) Nambu--Jona-Lasinio model.The rotational $1/N_c$ and strange quark mass corrections in linear order are taken into account. It turns out that the model is in good agreement with the experimental data.

S. M. Bilenky, C. Giunti

It is shown that the future SNO and Super-Kamiokande experiments, in which high energy $^8\mathrm{B}$ neutrinos will be detected through the observation of CC, NC and $ν$--$e$ elastic scattering processes, could allow to reveal in a model independent way the presence of sterile neutrinos in the flux of solar neutrinos on the earth.

G. Montagna, O. Nicrosini, F. Piccinini, F. M. Renard

We consider the possibility that one extra $Z\equiv Z'$ exists with arbitrary mass and fermion couplings that do not violate (charged) lepton universality. We show that, in such a situation, a functional relationship is generated between the \underline{deviations} from the SM values of three leptonic observables of two-fermion production at future $e^+e^

B. Ananthanarayan, Q. Shafi

We consider a realistic example of supersymmetric grand unification based on $SU(3)_c \times SU(3)_L \times SU(3)_R$ in which the electroweak (EW) higgs doublets are `light' as a consequence of the `pseudogoldstone' mechanism. We discuss radiative EW breaking in this model, exploring in particular the `small' (order unity) and `large' $(\appr

A. Ali Khan, C. T. H. Davies, S. Collins, J. Sloan

We present a lattice investigation of heavy-light mesons in the quenched approximation, using non-relativistic QCD for the heavy quark and a clover improved Wilson formulation for the light quark. A comprehensive calculation of the heavy-light spectrum has been performed for various heavy quark masses around the $b$. Our results for the $B_s-B_d$ splitting a

Daniel C. Galehouse

A theoretical study is made of conformal factors in certain types of physical theories based on classical differential geometry. Analysis of quantum versions of Weyl's theory suggest that similar field equations should be available in four, five and more dimensions. Various conformal factors are associated with the wave functions of source and test parti

Daniel C. Galehouse

Classical methods of differential geometry are used to construct equations of motion for particles in quantum, electrodynamic and gravitational fields. For a five dimensional geometrical system, the equivalence principle can be extended. Local transformations generate the effects of electromagnetic and quantum fields. A combination of five dimensional coordi

William Arveson

We show that a noncommutative dynamical system of the type that occurs in quantum theory can often be associated with a dynamical principle; that is, an infinitesimal structure that completely determines the dynamics. The nature of these dynamical principles is similar to that of the second order differential equations of classical mechanics, in that one can

Christopher Kumar Anand

Unitons, i.e.\ harmonic spheres in a unitary group, correspond to \lq uniton bundles\rq, i.e.\ holomorphic bundles over the compactified tangent space to the complex line with certain triviality and other properties. In this paper, we use a monad representation similar to Donaldson's representation of instanton bundles to obtain a simple formula for the

G. Santoro, M. Vendruscolo, S. Prestipino, E. Tosatti

We discuss the results of a study of restricted solid-on-solid models for fcc (110) surfaces. These models are simple modifications of the exactly solvable BCSOS model, and are able to describe a $(2\times 1)$ missing-row reconstructed surface as well as an unreconstructed surface. They are studied in two different ways. The first is by mapping the problem o

Walter Hofstetter, Malte Henkel

The spin-1 XY chain in a transverse field is studied using finite-size scaling. The ground state phase diagram displays a paramagnetic, an ordered ferromagnetic and an ordered oscillatory phase. The paramagnetic-ferromagnetic transition line belongs to the universality class of the 2D Ising model. Along this line, universality is confirmed for the finite-siz

F. Schmid, N. B. Wilding

We report large systematic errors in Monte Carlo simulations of the tricritical Blume-Capel model using single spin Metropolis updating. The error, manifest as a $20\%$ asymmetry in the magnetisation distribution, is traced to the interplay between strong triplet correlations in the shift register random number generator and the large tricritical clusters. T

M. Langer, J. Schmalian, S. Grabowski, K. H. Bennemann

We analyze the doping dependence of the intensity and energetical position of shadow states in high -T$_{c}$ superconductors within the 2D Hubbard model and using our recently developed numerical method for the self consistent summation of bubble and ladder diagrams. It is shown that shadow states resulting from short range antiferromagnetic correlations occ

Giuseppe Tormen

I use $N$-body simulations to investigate the morphology and the dynamical evolution and properties of dark matter halos in clusters of galaxies. My sample consists of nine massive halos, coming from an Einstein-de Sitter universe with scale free power spectrum and spectral index $n = -1$. Halos are resolved by 20,000 particles each, on average, and have a d

Wesley N. Colley, Linda S. Sparke

We have used a set of equations developed by Pringle (1992) to follow the evolution of a viscous twisted disk in a galaxy-like potential which is stationary or tumbling relative to inertial space. In an axisymmetric potential, the disk settles to the equatorial plane at a rate determined largely by the coefficient $ν_2$ associated with shear perpendicular to

Wesley N. Colley, J. Anthony Tyson, Edwin L. Turner

A unique reconstruction of the image of a high redshift source galaxy responsible for multiple long arcs in the z = 0.4 cluster 0024+1654 is obtained by inverse lensing. Deep B and I imaging with the Hubble Space Telescope (Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by

H. J. Mo, S. D. M. White

We develop a simple analytic model for the gravitational clustering of dark matter haloes to understand how their spatial distribution is biased relative to that of the mass. The statistical distribution of dark haloes within the initial density field (assumed Gaussian) is determined by an extension of the Press-Schechter formalism. Modifications of this dis

Ehud Cohen, Tsvi Piran

The analysis of the BATSE's count distribution within cosmological models suffers from observational uncertainties due to the variability of the bursts' spectra: when BATSE observes bursts from different redshifts at a fixed energy band it detects photons from different energy bands at the source. This adds a spectral dependence to the count distribu

Re'em Sari, Tsvi Piran

We calculate the hydrodynamic time scales for a spherical ultra-relativistic shell that is decelerated by the ISM and discuss the possible relations between these time scales and the observed temporal structure in $γ$-ray bursts. We suggest that the bursts' duration is related to the deceleration time, the variability is related to the ISM inhomogeneitie

Tsvi Piran, Ramesh Narayan

It is often stated that gamma-ray bursts (GRBs) have typical energies of several hundred keV. Is this a real feature of GRBs or is it due to an observational bias? We consider the possibility that bursts of a given bolometric luminosity occur with a hardness distribution $p(H)d \log H \propto H^γd \log H$. We model the detection efficiency of BATSE as a func

Guinevere Kauffmann

The analysis of disk formation is based on the White & Rees (1978) picture, in which disk galaxies form by continuous cooling and accretion of gas within a merging hierarchy of dark matter halos. A simple Kennicutt law of star formation for disks, based on a single- fluid gravitational instability model is introduced. Since the gas supply in the disk is regu

Achim Weiss, Josef Wagenhuber, Pavel A. Denissenkov

We follow the evolution of 3He in stars of mass 0.8 -- 10 M (solar units) for Pop. I and II compositions from the main sequence until advanced stages on the AGB. Under standard assumptions we confirm earlier results of more restricted investigations that low-mass stars up to 5 M are net producers of 3He. We show that the inclusion of additional mixing due to

Jean M. Quashnock

If gamma-ray bursts have a cosmological origin, the sources are expected to trace the large-scale structure of luminous matter in the universe. I use a new likelihood method that compares the counts-in-cells distribution of gamma-ray bursts in the BATSE 3B catalog with that expected from the known large-scale structure of the universe, in order to place a co

Fernando Torres

We extend results on Weierstrass semigroups at ramified points of double covering of curves to any numerical semigroup whose genus is large enough. As an application we strengthen the properties concerning Weierstrass weights in \cited{To}.

Stephen S. Pinsky, David G. Robertson

We consider SU(N) gauge theory in 1+1 dimensions coupled to chiral fermions in the adjoint representation of the gauge group. With all fields in the adjoint representation the gauge group is actually SU(N)/Z_N, which possesses nontrivial topology. In particular, there are N distinct topological sectors and the physical vacuum state has a structure analogous

Edmond L. Berger, L. E. Gordon

Contributions through second order, $O(α^2_s)$, in perturbative quantum chromodynamics are calculated analytically for inclusive associated production of a prompt photon and a charm quark at large values of transverse momentum in high energy hadron-hadron collisions. Seven partonic subprocesses contribute at order $α^2_s$. We find important corrections to th