June 1995 arXiv papers — page 7

James E. Lidsey

The canonical quantization of homogeneous cosmologies is considered in the high anisotropic limit. Exact wavefunctions are found in this limit when the momentum constraints are reduced at the classical level. Lorentzian solutions that represent tunnelling from classically forbidden regimes are identified. Solutions to the modified Wheeler-DeWitt equation are

Z. Y. Weng, D. N. Sheng, Y. C. Chen

Marshall sign as a sole source of sign problem hidden in an antiferromagnet is explored under doping. By tracking the Marshall sign, a zero spectral weight $Z$ is revealed in the doped antiferromagnetic system. $Z=0$ is caused by a phase string induced by the ``bare'' hole. By eliminating such a phase string through nonlocal transformations, a non-pe

Ludwig Schweitzer

The multifractal properties of electronic eigenstates at the metal-insulator transition of a two-dimensional disordered tight-binding model with spin-orbit interaction are investigated numerically. The correlation dimensions of the spectral measure $\widetilde{D}_{2}$ and of the fractal eigenstate $D_{2}$ are calculated and shown to be related by $D_{2}=2\wi

Oe. Lund Boe, Yu. Galperin, K. A. Chao

We have analyzed the effect of electron-LO phonon interaction in a double-barrier resonant tunneling structure under a magnetic field {\bf B} applied parallel to the tunneling current. While the low temperature anti-crossing phenomenon has already been investigated, here we study the phonon absorption resonant magnetotunneling at finite temperatures. The Mat

I. Pagonabarraga, J. Bafaluy, J. M. Rubi

We present a new class of sequential adsorption models in which the adsorbing particles reach the surface following an inclined direction (shadow models). Capillary electrophoresis, adsorption in the presence of a shear or on an inclined substrate are physical manifestations of these models. Numerical simulations are carried out to show how the new adsorptio

Xiao-Gang Wen, Patrick A. Lee

We develop a slave-boson theory for the t-J model at finite doping which respects an SU(2) symmetry -- a symmetry previously known to be important at half filling. The mean field phase diagram is found to be consistent with the phases observed in the cuprate superconductors, which contains d-wave superconductor, spin gap, strange metal, and Fermi liquid phas

V. Kushnir, B. Rosenstein

We develop a formalism for performing real space renormalization group transformations of the "decimation type" using low temperature perturbation theory. This type of transformations beyond $d=1$ is highly nontrivial even for free theories. We construct such a solution in arbitrary dimensions and develop a weak coupling perturbation theory for it. T

P. Collet

We consider the problem of reconstructing a function given its values on a set of points with finite density. We prove that with probability one, the values of an almost periodic function on a random array of points (with finite density) completely determine the function. We also give some properties of the associated Blaschke product.

B. Jönsson, M. Ullner, C. Peterson, O. Sommelius

Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. The Coulomb interactions are emulated by harmonic repulsive forces, the force constants being used as variational parameters to minimize the free energy. For the titrating charges, a mean field approach is used. The

V. Balaji, L. Brambila Paz, P. E. Newstead

Let $C$ be a nonsingular projective curve of genus $g\ge2$ defined over the complex numbers, and let $M_ξ$ denote the moduli space of stable bundles of rank $n$ and determinant $ξ$ on $C$, where $ξ$ is a line bundle of degree $d$ on $C$ and $n$ and $d$ are coprime. It is shown that the universal bundle $\cu_ξ$ on $C\times M_ξ$ is stable with respect to any p

R. Emparan

We argue that production of charged black hole pairs joined by a cosmic string in the presence of a magnetic field can be analyzed using the Ernst metric. The effect of the cosmic string is to pull the black holes towards each other, opposing to the background field. An estimation of the production rate using the Euclidean action shows that the process is su

Hsien-chung Kao

Following the work of Khare {\it et al}, we show that the generalization to systems with spontaneous symmetry breaking of the Coleman-Hill theorem to one-loop order, can be extended to the case including fermions with the most general interactions. Although the correction to the parity-odd part of the vacuum polarization looks complicated in the Higgs phase,

Roberto Iengo, Giancarlo Jug

We investigate the phenomenon of the decay of a supercurrent through homogeneous nucleation of vortex-antivortex pairs in a 2-D like superconductor or superfluid by means of a quantum electrodynamics formulation for the decay of the 2-D vacuum. The case in which both externally-driven current and Magnus force are present is treated exactly, taking the vortex

H. D. Zeh

Introduction to the theory of decoherence. Contents: 1. The phenomenon of decoherence: superpositions, superselection rules, decoherence by "measurements". 2. Observables as a derivable concept. 3. The measurement problem. 4. Density matrix, coarse graining, and "events". 5. Conclusions.

Carl Carlson, Probir Roy, Marc Sher

We use information from rare nonleptonic decays of heavy-quark mesons to put new bounds on the magnitudes of certain product combinations of baryon nonconserving R-parity violating couplings in supersymmetric models. Product combinations of lepton and baryon nonconserving R-parity violating couplings are also considered in the light of existing bounds on nuc

Sergey Finashin

Quotients $Y=X/conj$ of complex surfaces by anti-holomorphic involutions $conj\: X\to X$ tend to be completely decomposable when they are simply connected, i.e., split into connected sums, $n CP^2\#m\barCP2$, if $w_2(Y)\ne0$, or into $n(S^2\times S^2)$ if $w_2(Y)=0$. If $X$ is a double branched covering over $CP^2$, this phenomenon is related to unknottednes

Lucy Vanderwende

This paper describes an approach to the automatic identification of lexical information in on-line dictionaries. This approach uses bootstrapping techniques, specifically so that ambiguity in the dictionary text can be treated properly. This approach consists of processing an on-line dictionary multiple times, each time refining the lexical information previ

Per Elmfors, Benny Lautrup, Bo-Sture Skagerstam

Correlation measurements on the states of two-level atoms having passed through a micromaser at different times can be used to infer properties of the quantum state of the radiation field in the cavity. Long(short) correlation length in time is to some extent associated with super(sub)-Poissonian photon statistics. The correlation length is also an indicator

A. N. Artemyev, V. M. Shabaev, V. A. Yerokhin

The relativistic nuclear recoil corrections to the energy levels of low-laying states of hydrogen-like and high $Z$ lithium-like atoms in all orders in $αZ$ are calculated. The calculations are carried out using the B-spline method for the Dirac equation. For low $Z$ the results of the calculation are in good agreement with the $αZ$ -expansion results. It is

J. J. Halliwell

The path decomposition expansion is a path integral technique for decomposing sums over paths in configuration space into sums over paths in different spatial regions. It leads to a decomposition of the configuration space propagator across arbitrary surfaces in configuration space. It may be used, for example, in calculations of the distribution of first cr

M. Strikman, V. Guzey

The differential cross-section of inelastic coherent diffractive dissociation off nuclei $p~+~^4$He $\rightarrow X ~+ ~^4$He is expressed in terms of the relative cumulants of the cross-section distribution $P_N(σ)$. The theoretical result for the ratio $r=\Bigg(\frac{dσ_{diff}}{dt}\Bigg)^{pHe}_{t=0} \Bigg/ \Bigg(\frac{dσ_{diff}}{dt}\Bigg)^{pp}_{t=0}=6.8 ÷7.

Jun Hu, Dennis Sullivan

The classical criterion for a circle diffeomorphism to be topologically conjugate to an irrational rigid rotation was given by A. Denjoy. In 1985, one of us (Sullivan) gave a new criterion. There is an example satisfying Denjoy's bounded variation condition rather than Sullivan's Zygmund condition and vice versa. This paper will give the third criter

J. C. Brunelli, Ashok Das

We summarize all the known properties of the supersymmetric integrable Two Boson equation. We present its nonstandard Lax formulation and tri-Hamiltonian structure, its reduction to the supersymmetric nonlinear Schrödinger equation and the local as well as nonlocal conserved charges. We also present the algebra of the conserved charges and identify its secon

A. Bassetto, L. Griguolo, G. Nardelli

Pure Yang-Mills theories on the $S_1\times R$ cylinder are quantized in light-cone gauge $A_-=0$ by means of ${\bf equal-time}$ commutation relations. Positive and negative frequency components are excluded from the ``physical" Hilbert space by imposing Gauss' law in a weak sense. Zero modes, related to the winding on the cylinder, provide non trivia

V. Berezovoj, A. Pashnev

The superfield formulation of two - dimensional $N=4$ Extended Supersymmetric Quantum Mechanics (SQM) is described. It is shown that corresponding classical Lagrangian describes the motion in the conformally flat metric with additional potential term. The Bose and Fermi sectors of two- and three-dimensional $N=4$ SQM are analyzed. The structure of the quantu

Jisuke Kubo, Myriam Mondragon, George Zoupanos

The principles of finiteness and reduction of couplings can be applied to achieve Gauge-Yukawa Unification. It is found that the observed top-bottom hierarchy and the top quark mass naturally follow if there exists Gauge-Yukawa Unification which is a simple functional relation among the gauge coupling and the Yukawa couplings of the third generation in vario

P. Berglund, S. Katz, A. Klemm

The moduli dependence of $(2,2)$ superstring compactifications based on Calabi--Yau hypersurfaces in weighted projective space has so far only been investigated for Fermat-type polynomial constraints. These correspond to Landau-Ginzburg orbifolds with $c=9$ whose potential is a sum of $A$-type singularities. Here we consider the generalization to arbitrary q

Kazuhiko Odaka

We discuss an extension of the quantization method based on the induced representation of the canonical group.

J. J. Godina Nava, G. López Castro

We study the effects of charged tensor weak currents on the strangeness-changing decays of the $τ$ lepton. First, we use the available information on the $K^+_{e3}$ form factors to obtain BR$(τ^- \rightarrow K^-π^0 ν_τ)\sim {\cal O}(10^{-4})$ when the $Kπ$ system is produced in an antisymmetric tensor configuration. Then, we propose a mechanism for the direc

G. Montagna, O. Nicrosini, G. Passarino, F. Piccinini

The program {\tt TOPAZ0} is designed for computing $Z^0$ parameters, de-convoluted and QED-dressed cross sections and forward-backward asymmetries of $e^+ e^-$ annihilation into fermion pairs and of Bhabha scattering around the $Z^0$ peak, over both a completely inclusive experimental set-up and a realistic one, i.e. with cuts on acollinearity, energy or inv

Michael Wiest, Daniel R. Stump, Douglas O. Carlson, C. --P. Yuan

We calculate tree-level cross-sections for $W^{+}γ$ and $W^{+}W^{-}$ production in proton-antiproton collisions, with one $W$ decaying to leptons, with anomalous electroweak triple-boson coupling parameters $Δκ$ and $λ$. We compare the unpolarized cross-sections to those for a polarized proton beam, to study how a polarized proton beam would improve experime

V. A. Ilyin, T. Kaneko, Y. Kurihara, A. E. Pukhov

We have studied double Higgs production at future linear colliders while paying special attention to the option of high-energy and high-luminosity photon beams. The main purpose was to examine the feasibility of e+e-, e-gamma and gamma-gamma colliders in order to probe the anomalous triple Higgs coupling, which is crucial for understanding the Standard Model

G. Lazarides, C. Panagiotakopoulos

We propose a variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models. The observed temperature perturbations of cosmic background radiation can be reproduced with natural values of the parameters of the theory and a grand unification scale which is consistent with the unification of the minimal supersymmetric st

L. Trentadue

We present a new approach to semi-inclusive hard processes in QCD by means of $\it Fracture\;Functions$, hybrids between structure and fragmentation functions. We briefly motivate and describe it together with a list of possible applications.

A. Arbuzov, V. Fadin, E. Kuraev, L. Lipatov

We present the results of our calculations to a one, two, and three loop approximation of the e$^+$e$^-$$\rightarrow$e$^+$e$^-$ Bhabha scattering cross-section at small angles. All terms contributing to the radiatively corrected cross-section, within an accuracy of $δσ/ σ= 0.1 \% $, are explicitely evaluated and presented in an analytic form. $O(α)$ and $O(α

C. F. Baillie, D. A. Johnston

We simulate the Ising model on dynamical quadrangulations using a generalization of the flip move for triangulations with two aims: firstly, as a confirmation of the universality of the KPZ/DDK exponents of the Ising phase transition, worthwhile in view of some recent surprises with other sorts of dynamical lattices; secondly, to investigate the transition o

Giuseppe Beccarini, Massimo Bianchi, Stefano Capitani, Giancarlo Rossi

In this paper we present the 1-loop perturbative computation of the renormalization constants and mixing coefficients of the lattice quark operators of rank three whose hadronic elements enter in the determination of the second moment of Deep Inelastic Scattering (DIS) structure functions. We have employed in our calculations the nearest-neighbor improved ``

Fabio Cipriani, Daniele Guido, Sergio Scarlatti

In this paper we discuss trace properties of $d^+$-summable $K$-cycles considered by A.Connes in [\rfr(Conn4)]. More precisely we give a proof of a trace theorem on the algebra $\A$ of a $K$--cycle stated in [\rfr(Conn4)], namely we show that a natural functional on $\A$ is a trace functional. Then we discuss whether this functional gives a trace on the whol

Johannes Huebschmann

Let $Y$ be a CW-complex with a single 0-cell, $K$ its Kan group, a model for the loop space of $Y$, and let $G$ be a compact, connected Lie group. We give an explicit finite dimensional construction of generators of the equivariant cohomology of the geometric realization of the cosimplicial manifold $\roman{Hom}(K,G)$ and hence of the space $\roman{Map}^o(Y,

M. R. Norman

Group theory arguments have demonstrated that a general odd parity order parameter cannot have line nodes in the presence of spin-orbit coupling. In this paper, it is shown that these arguments do not hold on the $k_z = π/c$ zone face of a hexagonal close packed lattice. In particular, three of the six odd parity representations vanish identically on this fa

D. Braun, G. Montambaux

We have studied numerically the spectral correlations in a metallic phase and at the metal-insulator transition. We have calculated directly the two-point correlation function of the density of states $R(s,s')$. In the metallic phase, it is well described by the Random Matrix Theory (RMT). For the first time, we also find numerically the diffusive correc

N. Theodorakopoulos

The paper deals with the properties of thermally excited solitons of the isotropic spin-$S$ ferromagnetic chain with nearest-neighbor logarithmic interactions. The exact statistical mechanics of the interacting soliton gas is developed for the general case (arbitrary $S$, temperature and magnetic field). At low temperatures the model's thermodynamics coi

V. A. Kashurnikov, A. I. Podlivaev, N. V. Prokof'ev, B. V. Svistunov

We consider topological supercurrent excitations (SC) in 1D mesoscopic rings. Under certain conditions such excitations are well-defined except for (i) a tunneling between resonating states with clockwise and anti-clockwise currents, which may be characterized by the amplitude $Δ$, and (ii) a decay of SC assisted by phonons of the substrate, both effects bei

Megumi Kameyama

An account of utterance interpretation in discourse needs to face the issue of how the discourse context controls the space of interacting preferences. Assuming a discourse processing architecture that distinguishes the grammar and pragmatics subsystems in terms of monotonic and nonmonotonic inferences, I will discuss how independently motivated default pref

Neelima Gupte, R. E. Amritkar

We propose a mechanism by which the efficiency of mixing in chaotic flows can be enhanced. Our mechanism consists of introducing small changes in the system parameters in regions of phase space where the local Lyapunov exponent falls substantially below its average value. We have applied our mechanism to several typical chaotic maps and flows including a sys

Guillaume Evrard

Jaynes' transformation group principle is used to derive the objective prior for the velocity of a non-zero rest-mass particle. In the case of classical mechanics, invariance under the classical law of addition of velocities, leads to an improper constant prior over the unbounded velocity space of classical mechanics. The application of the relativistic

Stephen Serjeant, Mark Lacy, Steve Rawlings, Lindsay King

The extreme bolometric luminosity of IRAS F10214+4724, and in particular the huge mass in molecular gas inferred from the CO line fluxes have led to suggestions that this is a giant galaxy in the process of formation. An arc-like structure and the closeness of a second object suggest, however, that gravitational lensing may be responsible for its anomalously

R. Stompor, K. M. Gorski, A. J. Banday

The two-year COBE-DMR 53 and 90 GHz sky maps, in both galactic and ecliptic coordinates, are used to determine the normalisation of inflationary universe models with a flat global geometry and adiabatic density perturbations. The appropriately normalised cold and mixed dark matter models and cosmological constant dominated, cold dark matter models, computed

D. Grupe, K. Beuermann, K. Mannheim, H. -C. Thomas

We have identified the ROSAT source RX J0039.2-5117 with the previously almost unknown `narrow line' Seyfert 1 galaxy WPVS007 (z=0.028). The X-ray source displays quite unusual properties for an AGN. It was bright and ultrasoft in the ROSAT All-Sky Survey (RASS) and found at a level lower by a factor of ~ 400 in PSPC count rate in 1993. The implied 0.1-2

C. S. Reynolds, A. C. Fabian, K. Nandra, H. Inoue

We present a detailed re-analysis of the two {\it ASCA} Performance Verification observations of the nearby Seyfert 1 galaxy MCG-6-30-15. Confirming the results of Fabian et al. (1994), we find definite evidence for the {\sc O\,vii} and {\sc O\,viii} K-shell absorption edges of the warm absorber and a doubling of the warm absorber column density within the 3

F. P. Pijpers

This paper was presented at the Institute for Mathematics and its Applications workshop "Inverse problems in wave propagation" and will appear in the series IMA volumes (Springer). A brief overview of applications of inversions within astronomy is presented and also an inventory of techniques commonly in use. Most of this paper is focussed on the met

A. V. Balatsky, S. I. Matveenko

We consider the dynamical properties of simple edge states in integer ($ν= 1$) and fractional ($ ν= 1/2m+1$) quantum Hall (QH) liquids. The influence of a time-dependent local perturbation on the ground state is investigated. It is shown that the orthogonality catastrophe occurs for the initial and final state overlap $|<i|f>| \sim L^{-{1\over{2ν}}({δ\overπ}

P. Nason, M. H. Seymour

We study the effect of infrared renormalons upon shape variables that are commonly used to determine the strong coupling constant in $e^+e^-$ annihilation into hadronic jets. We consider the model of QCD in the limit of large $n_f$. We find a wide variety of different behaviours of shape variables with respect to power suppressed effects induced by infrared

G. Krenn, J. Summhammer, K. Svozil

We demonstrate that the preparation of a very well localized atom beam is possible without physical interaction. The preparation is based on the selection of an adequate ensemble of atoms of an originally wide beam by means of information obtained with a neutron interferometer. In such a case the uncertainty relation can no longer be interpreted as a by-prod

F. Kirchhoff, J. M. Holender, M. J. Gillan

Ab initio molecular dynamics simulations are used to investigate the structure and electronic properties of the liquid Ag-Se system at three compositions. The realism of the simulations is demonstrated by comparison with diffraction data for the stoichiometric case Ag$_2$Se. As the Se content is increased beyond the stoichiometric value, short-lived Se$_n$ c

K. C. Chou, Yue-Liang Wu

Based on a few basic assumptions, a predictive supersymmetric grand unification $G_{U}=SO(10)\times \Delta_{48}(SU(3))\times U(1)$ model is proposed. Thus, all the observed 45 chiral fermions with additional 3 right-handed neutrinos are unified into an irreducible triplet 16-dimensional spinor representation of $G_{U}$. Electroweak symmetry breaking naturall

Douglas C. Heggie, Frederic A. Rasio

We derive analytical expressions for the change in the orbital eccentricity of a binary following a distant encounter with a third star on a hyperbolic or parabolic orbit. To establish the accuracy of these expressions, we present detailed comparisons with the results of direct numerical integrations of the equations of motion for the three bodies. We treat

T. Goto, N. Kitazawa, Y. Okada, M. Tanaka

We present a framework to analyze effects of new physics beyond the standard model on $B$-$\bar B$ mixing and $CP$ violation in $B$ decays in a model-independent manner. Assuming that tree level decay amplitudes are dominated by the standard model ones, new physics contribution to the $B$-$\bar B$ mixing can be extracted from several measurements at $B$ fact

F. Grundahl, J. Hjorth

We present high-resolution CCD images (FWHM=0.6&#34;-0.7&#34;) of the compact gravitational lens system B0218+35.7 obtained at the Nordic Optical Telescope. Using aperture and PSF photometry we detect the two closely separated (335 mas) components A and B as well as the lensing galaxy. In the optical B seems to be very much brighter than A, opposite to the r

Kanehisa Takasaki

String equations of the $p$-th generalized Kontsevich model and the compactified $c = 1$ string theory are re-examined in the language of the Toda lattice hierarchy. As opposed to a hypothesis postulated in the literature, the generalized Kontsevich model at $p = -1$ does not coincide with the $c = 1$ string theory at self-dual radius. A broader family of so

Marina Galdón, M. A. Sanchis-Lozano

We discuss the possibility of extracting ${\mid}V_{cb}{\mid}$ from the future measurement at LHC of the $B_c\ {\rightarrow}\ J/ψ μ^+\ ν$ decay rate followed by the leptonic decay $J/ψ {\rightarrow}\ μ^+μ^-$. We examine in detail the influence of the measurement of the muons&#39; momenta and vertex reconstruction in the final uncertainty of ${\mid}V_{cb}{\mid

E. Ramos, J. Roca

We provide a description of W_3 transformations in terms of deformations of convex curves in two dimensional Euclidean space. This geometrical interpretation sheds some light on the nature of finite W_3-morphisms. We also comment on how this construction can be extended to the case of W_n and ``nicely curved&#39;&#39; curves in $\reals^{n-1}$.

Michael R. Gallis

Zurek, Habib and Paz [W. H. Zurek, S. Habib and J. P. Paz, Phys. Rev. Lett. {\bf 70} (1993)\ 1187] have characterized the set of states of maximal stability defined as the set of states having minimum entropy increase due to interaction with an environment, and shown that coherent states are maximal for the particular environment model examined. To generaliz

Ph. Blanchard, A. Jadczyk

We enhance the standard formalism of quantum theory to enable events. The concepts of experiment and of measurement are defined. Dynamics is given by Liouville&#39;s equation that couples quantum system to a classical one. It implies a unique Markov process involving quantum jumps, classical events and describing sample histories of individual systems.

S. Majid, M. J. Rodriguez-Plaza

We obtain the universal R-matrix of the non-standard quantum group associated to the Alexander-Conway knot polynomial. We show further that this non-standard quantum group is related to the super-quantum group $U_qgl(1|1)$ by a general process of superization, which we describe. We also study a twisted variant of this non-standard quantum group and obtain, a

Martin Bridgeman

In this paper we investigate how the volume of hyperbolic manifolds increases under the process of removing a curve, that is, Dehn drilling. If the curve we remove is a geodesic we are able to show that for a certain family of manifolds the volume increase is bounded above by $π\cdot l$ where $l$ is the length of the geodesic drilled. Also we construct examp

Q-Han Park, H. J. Shin

New aspects of the complex sine-Gordon theory are addressed through the reformulation of the theory in terms of the gauged Wess-Zumino-Witten action. A dual transformation between the theory for the coupling constant $\b > 0$ and the theory for $\b < 0$ is given which agrees with the Krammers-Wannier duality in the context of perturbed conformal field theory

Ramzi R. Khuri

I discuss the role of spacetime supersymmetry in the interplay between strong/weak coupling duality and target space duality in string theory which arises in string/string duality. This can be seen via the construction of string soliton solutions which in $N=4$ compactifications of heterotic string theory break more than $1/2$ of the spacetime supersymmetrie

Stanley J. Brodsky, Hung Jung Lu

We discuss three topics relevant to testing the Standard Model to high precision: commensurate scale relations, which relate observables to each other in pertubation theory without renormalization scale or scheme ambiguity, the relationship of compositeness to anomalous moments, and new methods for measuring the anomalous magnetic and quadrupole moments of t

V. Barger, W. -Y. Keung, R. J. N. Phillips

If $R$-parity is not conserved, the SUSY-threshold production process $e^+e^- \to \chi_1^0\chi_1^0$ could be detectable with relatively low luminosity. Hence an interesting mass range for the lightest SUSY particle $\chi_1^0$ could be explored at the CERN LEP collider during its intermediate energy development, even before the full LEP200 upgrade is complete

T. J. Fields, K. S. Gupta, J. P. Vary

We introduce a way of implementing Wilson renormalization within the context of the theory of effective Hamiltonians. Our renormalization scheme involves manipulations at the level of the generalized $G$--matrix and is independent of any specific kinematics. We show how to calculate the beta function within this context and exhibit our method using simple sc

Pierre Ramond

The addition of an Abelian family symmetry to the Minimal Supersymmetric Standard Model reproduces the observed hierarchies of quark and lepton masses and quark mixing angles, only if it is anomalous. Green-Schwarz compensation of its anomalies requires the electroweak mixing angle to be $\sin^2θ_w=3/8$ at the string scale, without any assumed GUT structure,

Jerrold Franklin

The measured masses of the three charge states of the charmed $Σ_c$ baryon are found to be in disagreement with a sum rule based on the quark model, but relying on no detailed assumptions about the form of the interaction. This poses a significant problem for the charmed baryon sector of the quark model. Other relations among charmed baryon masses are also d

Jonathan L. Rosner

Some aspects of $B$ physics relevant for experiments in hadron colliders are discussed. These include the determination of parameters of the CKM Matrix and confirmation of its role in CP violation, studies of mixing of nonstrange and strange $B$ mesons, lifetimes of hadrons containing $b$ quarks, the use of ``same-side&#39;&#39; tagging of neutral $B$ mesons

Aaron K. Grant, Jonathan L. Rosner, Andre Martin, Jean-Marc Richard

The spacings between bound-state levels of the Schrödinger equation with the same principal quantum number $N$ but orbital angular momenta $\ell$ differing by unity are found to be nearly equal for a wide range of power potentials $V = λr^ν$, with $E_{N \ell} \approx F(ν, N) - G(ν,N) \ell$. Semiclassical approximations are in accord with this behavior. The r

Kirsten Büttner, M. R. Pennington

The possible infrared behaviour of the gluon propagator is studied analytically, using the Schwinger-Dyson equations, in both the axial and the Landau gauge. The possibility of a gluon propagator less singular than $1/k^{2}$ when $k^{2} \rightarrow 0$ is investigated and found to be inconsistent, despite claims to the contrary, whereas an infrared enhanced o

C. Q. Geng, I. J. Hsu, Y. C. Lin

We study the long distance contribution to $K^+\toπ^+ν\bar{ν$ by using chiral perturbation theory. We find that the tree level $O(P^2)$ contribution vanishes identically without assuming the large $N_c$ limit. The leading contribution arises from the one-loop amplitude, which is $O(P^4)$ in the chiral power counting. The branching ratio of the long distance

E. L. Bratkovskaya, E. A. Kuraev, Z. K. Silagadze

The dominant contribution to the $π^0 \to 4γ$ branching ratio, coming from purely electromagnetic photon-splitting graph, is calculated. The result $Br(π^0 \to 4γ) \simeq (2.6 \pm 0.1) \cdot 10^{-11}$ is about three orders of magnitude below the present experimental limit.

V. Bernard, A. H. Blin, B. Hiller, Y. P. Ivanov

The momentum-space bosonization method of a Nambu and Jona-Lasinio type model with vector and axial-vector mesons is applied to $ππ$ scattering. Unlike the case in earlier published papers, we obtain the $ππ$ scattering amplitude using the linear and nonlinear realizations of chiral symmetry and fully taking into account the momentum dependence of meson vert

Yongseok Oh

The electric quadrupole moments of the decuplet baryons are calculated in the bound state approach of the Skyrme model. In this approach, all the quadrupole moments of the decuplets are found to be proportional to the third component of the baryon isospin. Contrary to the SU(3) collective model, the kaonic contribution is as important as the pionic one. The

F. Albiol, R. Pérez Ochoa, M. A. Sanchis-Lozano, J. A. Valls

We discuss the feasibility of the observation of the signal from $B_c$ mesons in the ATLAS experiment of the LHC collider at a luminosity of ${\approx}\ 10^{33}$cm$^{-2}$s$^{-1}$. In particular we address the decay mode $B_c{\rightarrow}J/ψπ$ followed by the leptonic decay $J/ψ{\rightarrow}μ^+μ^-$, which should permit an accurate measurement of the $B_c$ mas

Karl Jansen, Chuan Liu

We compare the Hybrid Monte Carlo (HMC) and the Kramers equation algorithms for simulations of QCD with two flavors of dynamical Wilson fermions and gauge group $SU(2)$. The results for the performance of both algorithms are obtained on $6^312$, $12^4$ and $16^4$ lattices at a pion to $ρ$ meson mass ratio of $m_π/m_ρ\approx 0.9$. We find that the Kramers equ

The CDF Collaboration

We analyze a sample of W + jet events collected with the Collider Detector at Fermilab (CDF) in ppbar collisions at sqrt(s) = 1.8 TeV to study ttbar production. We employ a simple kinematical variable &#34;H&#34;, defined as the scalar sum of the transverse energies of the lepton, neutrino and jets. For events with a W boson and four or more jets, the shape

Yuri A. Kordyukov

We study spectral asymptotics for the Laplace operator on differential forms on a Riemannian foliated manifold equipped with a bundle-like metric in the case when the metric is blown up in directions normal to the leaves of the foliation. The asymptotical formula for the eigenvalue distribution function is obtained. The relationships with the spectral theory

Manuel Fuentes, Ana Lopez, Eduardo Fradkin

We report exact results for the partition function for free Dirac fermions on a half line with physically sensible boundary conditions. An exact effective action for general backscattering amplitudes is derived. The action also includes the effects of both a (time-dependent) forward scattering amplitude and a dynamical chiral twist of the fermion boundary co

D. M. Kagan, M. V. Feigelman

We have studied dynamical behaviour of the infinite-range Ising spin glass model with $p$-spin interaction above and below the transition into the non-ergodic phase. The transition is continuous at sufficiently high external magnetic field. The dynamic critical exponent of the power-law decay of the autocorrelation function at the transition point is shown t

Leticia F. Cugliandolo, J. Kurchan, Remi Monasson, Giorgio Parisi

We present a model of spheres moving in a high-dimensional compact space. We relate it to a mixed matrix model with a $O(N)$ invariant model plus a $P(N)$ invariant perturbation. We then study the low pressure regime by performing a diagrammatic expansion of this matrix model. Finally, we show the results from numerical simulations and we present evidence fo

Gilles Montambaux

The average persistent current <I> of diffusive electrons in the Hartree-Fock approximation is derived in a simple non-diagrammatic picture. The Fourier expansion directly reflects the winding number decomposition of the diffusive motion around the ring. One recovers the results of Ambegaokar and Eckern, and Schmid. Moreover one finds an expression for <I> w

S. Della Pietra, V. Della Pietra, J. Lafferty

We present a technique for constructing random fields from a set of training samples. The learning paradigm builds increasingly complex fields by allowing potential functions, or features, that are supported by increasingly large subgraphs. Each feature has a weight that is trained by minimizing the Kullback-Leibler divergence between the model and the empir

Dominique Estival, Francoise Gayral

This paper addresses the issue of defining context, and more specifically the different contexts needed for understanding a particular type of texts. The corpus chosen is homogeneous and allows us to determine characteristic properties of the texts from which certain inferences can be drawn by the reader. These characteristic properties come from the real wo

R. G. Carlberg

Galaxy merging is the late time manifestation of the galaxy formation process and likely significantly effects $z<1$ galaxies. A ``maximum reasonable rate&#39;&#39; model for merging finds a $\sim2$ mag K band increase in the luminosities of dwarf galaxies so that they contribute significantly to the faint counts, with spirals and ellipticals being far less

Mario Vietri

UHECRs are roughly isotropic and attain very large energies, $E \gtrsim 3\times 10^{20} \; eV$. Conventional models fail to explain both facts. I show here that acceleration of UHECRs in GRBs satisfies both observational constraints. Using Mészáros and Rees&#39; (1994) model of GRBs as due to hyperrelativistic shocks, I show that the highest energies that ca

Michel Boer, Jochen Greiner, Christian Motch

We report on deep photometry and spectroscopy of the objects detected in the ROSAT HRI X-ray error box of the hard X-ray transient, GRS 1915+105. The probable counterpart of this source has been detected, with a magnitude of 23.4 in the I band. The optical absorption ${\rm A}_{\rm V} = 28$ derived from the X-ray data implies an absolute magnitude in the I ba

Charles Curry, Ralph E. Pudritz

We investigate the global stability of a differentially rotating fluid shell threaded by vertical and azimuthal magnetic fields to linear, axisymmetric perturbations. This system, which models a thick accretion disk in the vicinity of its midplane, is susceptible to the Velikhov-Chandrasekhar (VC) instability in the absence of the azimuthal field. In most ca

D. DeLaney, S. Jadach, S. M. Kim, Ch. Shio

We apply our Yennie-Frautschi-Suura exponentiated cross section formulas for the parton processes $q + {^(} \bar q {^)}{^\prime} \ra q{^\prime}{^\prime} + {^(} \bar q {^)}{^\prime}{^\prime}{^\prime} + n(G)$ to the process $q + \bar q \ra t + \bar t + n(G)$ at FNAL energies, where G is a QCD gluon. We use semi-analytical methods to compute the ratio $r_{exp}=

F. Hammer, D. Crampton, O. Le Fevre, S. Lilly

Deep imaging and spectroscopy have been carried out for optical counterparts of a complete sample of S$>$16 $μ$Jy radiosources during the course of the Canada-France Redshift Survey (CFRS). All 36 sources but two have been optically identified, and spectra have been obtained for 23 of them. The objects brighter than $I_{AB}<$22.5 for which we have spectra re

Francois Lauze

In this paper, I compute the last non-trivial term of the minimal free resolution of the homogeneous ideal of $s$ points of $P^n$ in sufficiently general position, for any $s$, showing that this term is the one conjectured by the Minimal Resolution Conjecture of Anna Lorenzini. I use a geometrical method, the &#34;vectorial méthode d&#39;Horace&#34; developp

D. Ebert, T. Feldmann, C. Kettner, H. Reinhardt

We present a phenomenological ansatz for coupling a heavy quark with two light quarks to form a heavy baryon. The heavy quark is treated in the heavy mass limit, and the light quark dynamics is approximated by propagating scalar and axial vector &#39;diquarks&#39;. The resulting effective lagrangian, which incorporates heavy quark and chiral symmetry, descri

J. Donin, S. Shnider

Given an associative algebra $A$, and the category, $\cC$, of its finite dimensional modules, additional structures on the algebra $A$ induce corresponding ones on the category $\cC$. Thus, the structure of a rigid quasi-tensor (braided monoidal) category on $Rep_A$ is induced by an algebra homomorphism $A\to A\otimes A$ (comultiplication), coassociative up

Sudhansu S. Mandal, V. Ravishankar

We propose a global model which accounts for all the observed quantum Hall states in terms of an abelian doublet of Chern-Simons gauge fields, with the strength of the Chern-Simons term given by a coupling matrix. The model is employed within the composite fermion picture.