November 1998 arXiv papers — page 14

Thomas K. Gaisser

The atmospheric neutrino beam simultaneously spans a range of pathlengths from ten to ten thousand kilometers, which correspond respectively to downward- and upward-going neutrinos. As with any neutrino oscillation experiment, also in this case the interpretation of the data depends on a detailed knowledge of the neutrino beam. The ingredients are the primar

Thomas K. Gaisser

Measurements of the intensity of primary cosmic-ray protons reported in the last two years suggest a lower normalization than some earlier measurements. Here we comment on the measurements, compare them to assumptions made in two independent calculations of atmospheric neutrinos and discuss the possible consequences for interpretation of measurements of atmo

Kenneth Intriligator

This talk is an overview of selected topics related to renormalization group flows and the phases of gauge theories.

Gert Aarts, Jan Smit

We consider the dynamics of the 1+1 dimensional abelian Higgs model with axially coupled fermions, in the large N_f limit, on a lattice in space and real-time. We allow for inhomogeneous classical Bose fields. In order to deal with the lattice doublers, we use Wilson's lattice fermions. The lattice formulation leads to a stable integration algorithm. We

Hermann Schulz

Well known from the sixties, the pressure of e.g. massless phi-four theory may be written as a series of 2PI-diagrams (skeletons) with the lines fully dressed. Varying the self-energy Pi in this expression, it turns into a functional U[Y] having a maximum in function space at Y=Pi. There is also the Feynman-Jensen thermal variational principle V[S], a potent

Richard Nisius

Some general considerations on a future linear collider and selected topics of two photon physics measurements which can be performed at such a collider are presented. This review discusses the total photon-photon cross section, jet cross sections, structure functions, charm production, the BFKL Pomeron, $W$ pair production, and Higgs production.

M. Trucks

In this letter we summarize our analysis of Bose-Einstein condensation on closed Robertson-Walker spacetimes. In a previous work we defined an adiabatic KMS state on the Weyl-algebra of the free massive Klein-Gordon field. This state describes a free Bose gas on Robertson-Walker spacetimes. We use this state to analyze the possibility of Bose-Einstein conden

Robert C. Myers

A review of recent investigations of black holes in higher curvature theories of gravity.

A. Bartoli, J. Julve, E. J. Sanchez

Linearized four-derivative gravity with a general gauge fixing term is considered. By a Legendre transform and a suitable diagonalization procedure it is cast into a second-order equivalent form where the nature of the physical degrees of freedom, the gauge ghosts, the Weyl ghosts, and the intriguing "third ghosts", characteristic to higher-derivativ

C. Klein, O. Richter

Riemann--Hilbert techniques are used in the theory of completely integrable differential equations to generate solutions that contain a free function which can be used at least in principle to solve initial or boundary value problems. The solution of a boundary value problem is thus reduced to the identification of the jump data of the Riemann-Hilbert proble

Wu Zhong Chao

We study pair creation of Kerr-Newman-anti-de Sitter and Kerr-Newman-de Sitter black holes.

Lance Fortnow, John D. Rogers

We use the powerful tools of counting complexity and generic oracles to help understand the limitations of the complexity of quantum computation. We show several results for the probabilistic quantum class BQP. 1. BQP is low for PP, i.e., PP^BQP=PP. 2. There exists a relativized world where P=BQP and the polynomial-time hierarchy is infinite. 3. There exists

Bernardo Kastrup

A high-level architecture of a Hybrid Reconfigurable CPU, based on a Philips-supported core processor, is introduced. It features the Philips XPLA2 CPLD as a reconfigurable functional unit. A compilation chain is presented, in which automatic implementation of time-critical program segments in custom hardware is performed. The entire process is transparent f

A. W. Sandvik

In a recent Letter [Europhys. Lett. 40, 429 (1997)], Hartmann presented results for the structure of the degenerate ground states of the three-dimensional +/- J spin glass model obtained using a genetic algorithm. In this Comment, I argue that the method does not produce the correct thermodynamic distribution of ground states and therefore gives erroneous re

D. A. Ivanov, M. V. Feigel'man

Superconducting quantum point contacts are known to possess two subgap states per each propagating mode. In this note we compute the low-temperature relaxation rate of the upper subgap state into the lower one with the emission of an acoustic phonon. If the reflection in the contact is small, the relaxation time may become much longer than the characteristic

Elena V. Goldstein, Pierre Meystre

We present an exact quantum mechanical analysis of collinear four-wave mixing in a multicomponent Bose-Einstein condensate consisting of sodium atoms in the F=1 ground state. Technically, this is achieved by taking advantage of the conservation laws of the system to represent its Hamiltonian in terms of angular momentum operators. We discuss explicitly the b

B. Rosenow, R. Oppermann

We discuss a metal-insulator transition caused by random couplings of magnetic moments in itinerant systems. An analytic solution for the single particle Green function is derived from dynamical self consistency equations, the corresponding density of states is characterized by the opening of a gap. The scaling behavior of observables is analyzed in the fram

I. S. Beloborodov, K. B. Efetov

The magnetoresistance of a granular superconductor in a strong magnetic field destroying the gap in each grain is considered. It is assumed that the tunneling between grains is sufficiently large such that all conventional effects of localization can be neglected. A non-trivial sensitivity to the magnetic field comes from superconducting fluctuations leading

F. Lesage, H. Saleur

By applying methods of integrable quantum field theory to the Kondo problem, we develop a systematic perturbation expansion near the IR (strong coupling) fixed point. This requires the knowledge of an infinity of irrelevant operators and their couplings, which we all determine exactly. A low temperature expansion (ie all the corrections to Fermi liquid theor

P. Tangney, S. Fahy

Calculations of the A_1 phonon frequency in photoexcited tellurium are presented. The phonon frequency as a function of photoexcited carrier density and phonon amplitude is determined. Recent pump probe experiments are interpreted in the light of these calculatons. It is proposed that, in conjunction with measurements of the phonon period in ultra-fast pump-

K. Saito, S. Takesue, S. Miyashita

Nature of energy transport around a critical point is studied in the Creutz cellular automaton. Fourier heat law is confirmed to hold in this model by a direct measurement of heat flow under a temperature gradient. The thermal conductivity is carefully investigated near the phase transition by the use of the Kubo formula. As the result, the thermal conductiv

Bernhard A. Kaufmann, Franz Schwabl, Uwe C. T"auber

We study the critical dynamics of crystals which undergo a second-order phase transition from a high-temperature normal phase to a structurally incommensurate (IC) modulated phase. We give a comprehensive description of the critical dynamics of such systems, e.g. valid for crystals of the A_2BX_4 family. Using an extended renormalization scheme, we present a

P. Pieri, G. C. Strinati

We consider the problem of the crossover from BCS superconductivity to Bose-Einstein condensation in three dimensions for a system of fermions with an attractive interaction, for which we adopt the simplifying assumption of a suitably regularized point-contact interaction. We examine in a critical way the fermionic (self-consistent) T-matrix approximation wh

M. T. Batchelor

The hamiltonian of an asymmetric diffusion process with injection and ejection of particles at the ends of a chain of finite length is known to be relevant to that of the spin-1/2 XXZ chain with integrable boundary terms. However, the inclusion of boundary sources and sinks of particles breaks the arrow-reversal symmetry necessary for solution via the usual

A. Jellal

The paper has been withdrawn by the author.

A. Jellal

The article has been withdrawn by the author.

A. Jellal

The article has been withdrawn by the author.

A. Jellal

The paper has bene withdrawn by the author.

Kiran M. Kolwankar, Anil D. Gangal

It is wellknown that the ordinary calculus is inadequate to handle fractal structures and processes and another suitable calculus needs to be developed for this purpose. Recently it was realized that fractional calculus with suitable constructions does offer such a possibility. This makes it necessary to have a definition of fractal measures based on the fra

Thomas S. Statler, Tammy Smecker-Hane

We have measured the stellar kinematic profiles of NGC 3379 along four position angles using the MMT. The data extend 90" from the center, at essentially seeing-limited resolution out to 17". The mean velocities and dispersions have total errors better than 10 km/s (frequently better than 5 km/s) out to 55". We find very weak (3 km/s) rotation on

Nicholas B. Suntzeff, M. M. Phillips, R. Covarrubias, M. Navarrete

We present the UBVRI light curves of the Type Ia supernova SN 1998bu which appeared in the nearby galaxy M96 (NGC 3368). M96 is a spiral galaxy in the Leo I group which has a Cepheid-based distance. Our photometry allows us to calculate the absolute magnitude and reddening of this supernova. These data, when combined with measurements of the four other well-

Martin D. Weinberg

The satellite-disk interaction provides limits on halo properties in two ways: (1) physical arguments motivate the excitation of observable Galactic disk structure in the presence of a massive halo, although precise limits on halo parameters are scenario-dependent; (2) conversely, the Milky Way as a whole has significant dynamical effect on LMC structure and

M. J. Hardcastle, P. Alexander, G. G. Pooley, J. M. Riley

In a previous paper we presented measurements of the properties of jets and cores in a large sample of FRII radio galaxies with z<0.3. Here we test, by means of Monte Carlo simulations, the consistency of those data with models in which the prominences of cores and jets are determined by relativistic beaming. We conclude that relativistic beaming is needed t

H. Flores, F. Hammer, T. Thuan, C. Césarsky

The CFRS 1452+52 field has been deeply imaged with the Infrared Space Observatory (ISO) using ISOCAM through the LW3 filter (12-18um). Careful data analysis and comparison to deep optical and radio data have allowed us to generate a catalog of 78 15um sources with both radio and optical identifications. They are redder and lie at higher redshift than I-band

H. Flores, F. Hammer, F. X. Désert, C. Césarsky

Deep 6.75um mid-IR ISOCAM observations were obtained of the Canada-France Redshift Survey (CFRS) 1415+52 field with the Infrared Space Observatory. The identification of the sources with optical counterparts is described in detail, and a classification scheme is devised which depends on the S/N of the detection and the inverse probability of chance coinciden

W. Stolzmann, T. Bloecker

Using the technique of Pade Approximants for the correlation contributions of charged particles we are able to reproduce complex mathematical expressions by simple algebraic formulas. The Pade formulas are analytical expressions, which interpolate between certain density-temperature regions and are characterized by exact asymptotics. We present a semi-relati

P. A. M. de Theije, P. Katgert

We used the galaxy spectra obtained in the ESO Nearby Abell Cluster Survey (ENACS) to separate early- and late-type galaxies in the ENACS clusters, by applying a Principal Component Analysis (PCA) in combination with an Artificial Neural Network (ANN). We represented the spectra by 15 Principal Components, which form the input for the ANN. The latter was tra

A. Merloni, M. Vietri, L. Stella, D. Bini

We compute exactly the Lense-Thirring precession frequency for point masses in the Kerr metric, for arbitrary black hole mass and specific angular momentum. We show that this frequency, for point masses at or close to the innermost stable orbit, and for holes with moderate to extreme rotation, is less than, but comparable to the rotation frequency. Thus, if

Ren Xin Xu, G. J. Qiao

It is proposed that the `bare&#39; strange matter stars might not be bare, and radio pulsars might be in fact `bare&#39; strange stars. As strange matter stars being intensely magnetized rotate, the induced unipolar electric fields would be large enough to construct magnetospheres. This situation is very similar to that discussed by many authors for rotating

Arnon Dar

In a letter with the above title, published some time ago in PRL, Waxman made the interesting suggestion that cosmological gamma ray bursts (GRBs) are the source of the ultra high energy cosmic rays (UHECR). This has also been proposed independently by Milgrom and Usov and by Vietri. However, recent observations of GRBs and their afterglows and in particular

Ohad Shemmer, Shai Kaspi

We report the discovery of a nearby M dwarf star, found accidentally while observing the old nova DN Gem at the Wise Observatory. The star is designated 1200-05296925 in the PMM USNO-A1.0 catalogue and its coordinates, calculated for 1997 November 27 are: RA=6 55 05.13 Dec = +32 09 54.1 (Equinox J2000, Epoch J1997.90). Astrometric measurements for the star y

Martin Harwit

The density of the far infrared / submillimeter (FIR/SMM) diffuse extragalactic radiation field has recently been determined from COBE data. Nearly simultaneously, deep FIR/SMM surveys have detected substantial numbers of optically unidentified sources, which have led to the proposal that galaxies and protogalaxies at red shifts z = 2 to 4 may account for an

V. V. Usov

I reply to A. Mitra&#39;s comment on my PRL paper &#34;Bare quark matter surfaces of strange stars and $e^+e^-$ emission&#34;. I show that his points of criticism are not correct.

S. Leon, F. Combes, D. Friedli

NGC 5850 is a prototype of double-barred galaxy (Friedli et al. 1996) classified as SBb(sr) I-II (Higdon et al. 1998; Prieto et al. 1997). This kind of system is primordial to understand the physical mechanism responsible for feeding galaxy nuclei and boost the star formation rate. The CO(1-0) emission has been mapped in NGC 5850, i) in the very center, usin

Halton Arp

D. Reimers and H.-J. Hagen report in A&A 329, L25 (1998) that a QSO of z = .807 is a &#34;by chance projection&#34; on the center of a galaxy of z = .009. A considerable amount of previously published evidence would lead us to expect an active, low redshift galaxy within about one degree of such a quasar. It is shown here that, in fact, there is a bright Sey

T. Driebe, D. Schoenberner, T. Bloecker, F. Herwig

We present seven evolutionary tracks for low-mass white dwarfs with helium cores, ranging in mass from 0.179 to 0.414 Msol. We generated the pre-white dwarf models from a 1 Msol sequence extending up to the tip of its red-giant branch by applying high mass-loss rates at appropriate positions, and we followed their evolution across the Hertzsprung-Russell dia

Narciso Benitez

Photometric redshift estimation is becoming an increasingly important technique, although the currently existing methods present several shortcomings which hinder their application. Here it is shown that most of those drawbacks are efficiently eliminated when Bayesian probability is consistently applied to this problem. The use of prior probabilities and Bay

Kristen Menou, Jean-Marie Hameury, Rudolf Stehle

We use high-resolution time-dependent numerical simulations of accretion discs around white dwarfs to study the structure and properties of transition fronts in the context of the thermal-viscous disc instability model. The thermal structure of cooling and heating fronts is dominated by radiative cooling and viscous heating, respectively, except in a very na

Scott C. Chapman, Douglas Scott, Geraint F. Lewis, Colin Borys

We present a detailed mm-wave and optical study of the gravitational lens system B1933+503, discovered by Sykes et al.(1998) in the radio. This object is probably the most complex lens system known, with 10 lensed components within a radius of one arcsecond. It is potentially important as a probe of the Hubble constant, although no optical counterpart has th

L. Van Waerbeke, F. Bernardeau, Y. Mellier

We apply a mass reconstruction technique to simulated large-scale structure gravitational distortion maps, from 2.5&#39; to 10 degree scales, for different cosmological scenarii. The projected mass is reconstructed using a non-parametric least square method after noise due to the galaxy intrinsic ellipticities has been added on. The shearing of the galaxies

G. I. Gomero, A. F. F. Teixeira, M. J. Reboucas, A. Bernui

If the universe is multiply connected and small the sky shows multiple images of cosmic objects, correlated by the covering group of the 3-manifold used to model it. These correlations were originally thought to manifest as spikes in pair separation histograms (PSH) built from suitable catalogues. Using probability theory we derive an expression for the expe

Tanmay Vachaspati, Mark Trodden

In the context of inflationary models with a pre-inflationary stage, in which the Einstein equations are obeyed, the weak energy condition is satisfied, and spacetime topology is trivial, we argue that homogeneity on super-Hubble scales must be assumed as an initial condition. Models in which inflation arises from field dynamics in a Friedman-Robertson-Walke

I. N. Mishustin

Non-equilibrium features of a first order phase transition from the quark-gluon plasma to a hadronic gas in relativistic heavy-ion collisions are discussed. It is demonstrated that strong collective expansion may lead to the fragmentation of the plasma phase into droplets surrounded by undersaturated hadronic gas. Subsequent hadronization of droplets will ge

F. F. Ferreira, J. F. Fontanari

The number partitioning problem consists of partitioning a sequence of positive numbers ${a_1,a_2,..., a_N}$ into two disjoint sets, ${\cal A}$ and ${\cal B}$, such that the absolute value of the difference of the sums of $a_j$ over the two sets is minimized. We use statistical mechanics tools to study analytically the Linear Programming relaxation of this N

M. A. R. de Cara, O. Pla, F. Guinea

The El Farol bar model, proposed to study the dynamics of competition of agents in a variety of contexts (W. B. Arthur, Amer. Econ. Assoc. Pap. and Proc. 84, 406 (1994)) is studied. We characterize in detail the three regions of the phase diagram (efficient, inefficient and better than random) of the simplest version of the model (D. Challet and Y.-C. Zhang,

Roman Scoccimarro, Joshua A. Frieman

We consider the long-standing problem of predicting the hierarchical clustering amplitudes $S_p$ in the strongly non-linear regime of gravitational evolution. N-body results for the non-linear evolution of the bispectrum (the Fourier transform of the three-point density correlation function) suggest a physically motivated ansatz that yields the strongly non-

H. Nunokawa, R. Tomas, J. W. F. Valle

The present solar and atmospheric neutrino data together with the LSND results and the presence of hot dark matter (HDM) suggest the existence of a sterile neutrino at the eV scale. We have reanalysed the effect of resonant {\sl sterile} neutrino conversions induced by neutrino magnetic moments in a type-II supernova. We analyse the implications of $ν_e-ν_s$

A. F. Volkov, V. V. Pavlovskii, R. Seviour

Using an approach based on quasiclassical Green&#39;s functions we present a theoretical study of transport in mesoscopic S/N structures in the diffusive limit. The subgap conductance in S/N structures with barriers (zero bias and finite bias anomalies) are discused. We also analyse the temperature dependence of the conductance variation $δS(T)$ for a Andree

Pratip Bhattacharyya

A one-dimensional cellular automaton with a probabilistic evolution rule can generate stochastic surface growth in $(1 + 1)$ dimensions. Two such discrete models of surface growth are constructed from a probabilistic cellular automaton which is known to show a transition from a active phase to a absorbing phase at a critical probability associated with two p

J. B. Gomez, M. Vazquez-Prada, Y. Moreno, A. F. Pacheco

For years limited Monte Carlo simulations have led to the suspicion that the time to failure of hierarchically organized load-transfer models of fracture is non-zero for sets of infinite size. This fact could have a profound significance in engineering practice and also in geophysics. Here, we develop an exact algebraic iterative method to compute the succes

Carlo Baccigalupi

I consider the case of anisotropies in the Cosmic Microwave Background (CMB) from one single ordered perturbation source, or seed, existing well before decoupling between matter and radiation. Such structures could have been left by high energy symmetries breaking in the early universe. I focus on the cases of spherical and cylindrical symmetry of the seed.

Alex Kovner, Benjamin Svetitsky

We use a variational wave function to calculate the energy of the interaction between external charges in the compact Abelian gauge theory in 2+1 dimensions with mixed action. Our variational wave functions preserve the compact gauge invariance of the theory both in the vacuum and in the charged sectors. We find that a good estimate of the interaction energy

Shahar Hod

We study analytically the asymptotic late-time evolution of realistic rotating collapse. This is done by considering the asymptotic late-time solutions of Teukolsky&#39;s master equation, which governs the evolution of gravitational, electromagnetic, neutrino and scalar perturbations fields on Kerr spacetimes. In accordance with the no-hair conjecture for ro

A. K. Nguyen, A. Sudbø

A phase transition within the molten phase of the Abrikosov vortex system without disorder in extreme type-II superconductors is found via large-scale Monte-Carlo simulations. It involves breaking a U(1)-symmetry, and has a zero-field counterpart, unlike vortex lattice melting. Its hallmark is the loss of number-conservation of connected vortex paths threadi

Shibaji Roy

Kaluza-Klein monopole and H-monopole solutions, which are T-dual to each other, are the well-known solutions of string theory compactified on $T^6$. Since string theory in this case has an S-duality symmetry, we explicitly construct the corresponding dyonic solutions by expressing the $D = 4$ string effective action in a manifestly $SL(2, R)$ invariant form

T. Gutsche, R. Vinh Mau, M. Strohmeier-Presicek, A. Faessler

A detailed analysis of the radiative $p\bar p$ annihilation is made in the framework of a two-step formalism, the $p\bar p$ annihilates into meson channels containing a vector meson with a subsequent conversion into a photon via the vector dominance model (VDM). Both steps are derived from the underlying quark model. First, branching ratios for radiative pro

Chao-Shang Huang, Hua-Gang Yan

Rare decays $Λ_b \to Λγ$ and $Λ_b \to Λl^{+} l^{-}$ (l= e, $μ$) are examined. We use QCD sum rules to calculate the hadronic matrix elements governing the decays. The $Λ$ polarization in the decays is analyzed and it is shown that the polarization parameter in $Λ_b \to Λγ$ does not depends on the values of hadronic form factors. And the energy spectrum of $Λ

Istvan Racz

In covariant metric theories of coupled gravity-matter systems the necessary and sufficient conditions ensuring the existence of a Killing vector field are investigated. It is shown that the symmetries of initial data sets are preserved by the evolution of hyperbolic systems.

Thomas C. Hales, Sean McLaughlin

The dodecahedral conjecture states that the volume of the Voronoi polyhedron of a sphere in a packing of equal spheres is at least the volume of a regular dodecahedron with inradius 1. The authors prove the conjecture following the methodology of the proof the Kepler conjecture. (See math.MG/9811071.)

R. Chitra, G. Kotliar

We study the antiferromagnetic metal to antiferromagnetic insulator using dynamical mean field theory and exact diagonalization methods. We find two qualitatively different behaviors depending on the degree of magnetic correlations. For strong correlations combined with magnetic frustration, the transition can be described in terms of a renormalized slater t

Alex Kasman

The Baker-Akhiezer (wave) functions corresponding to soliton solutions of the KP hierarchy are shown to satisfy eigenvalue equations for a commutative ring of translational operators in the spectral parameter. In the rational limit, these translational operators converge to the differential operators in the spectral parameter previously discussed as part of

Alexander A. Vlasov

It is proved that in classical electrodynamics the uniform rectilinear motion of charged &#34;rigid&#34; sphere with self-action (Sommerfeld model) is stable.

Alexander A. Vlasov

On simple example is shown that a model of mechanically extended source of radiation in classical electrodynamics indeed has some problems with radiation reaction force. So one cannot, in general case, state, that the present situation with classical dynamics of mechanically extended sources of radiation is &#34;very satisfactory&#34;.

A. Yu. Korchin, O. Scholten, R. G. E. Timmermans

Results of a relativistic model for pion- and photon-induced reactions on the proton are presented. The model is crossing symmetric and gauge invariant. The nucleon resonances P_11 (1440), P_11 (1710), D_13 (1520), S_11 (1535), S_11 (1650), P_33 (1232), P_33 (1600), S_31 (1620), and D_33 (1700) have been included explicitly in the calculation. Unitarity with

S. Acharya, L. Maharana, R. Mohanty, P. K. Panda

The phase transition between the nuclear matter and the quark matter is examined. The relativistic mean field theory(RMF) is consider with interacting nucleons and mesons using TM1 parameter set for the nuclear matter equations of state. It is found that the trasition point depends on coupling constant $α_s$ and bag pressure. From the study of the structure

B. Friman, M. Lutz, G. Wolf

We emphasize the central role played by the spectral function in the description of hadrons in matter and discuss the applicability of the quasiparticle concept to the propagation of hadrons in dense nuclear matter. Theoretical and experimental results relevant for the in medium properties of vector mesons and kaons are briefly reviewed. We also present nove

Zhangbu Xu, for E864 Collaboration

We report on the latest results in the search for positively charged strangelets from E864&#39;s 96/97 run at the AGS with sensitivity of about $8\times 10^{-9}$ per central collision. This contribution also contains new results of a search for highly charged strangelets with $Z=+3$. Production of light nuclei, such as $^6He$ and $^6Li$, is presented as well

Alex Kasman

A set of functions is defined which is indexed by a positive integer $n$ and partitions of integers. The case $n=1$ reproduces the standard Schur polynomials. These functions are seen to arise naturally as a determinant of an action on the frame bundle of an infinite grassmannian. This fact is well known in the case of the Schur polynomials ($n=1$) and has b

T. Skrypnyk

New commutative subalgebras of the maximal Gel&#39;fand-Kirillov dimension in the universal enveloping algebras of classical Lie algebras gl(n) and so(n) are constructed. In the case of sp(n) Gel&#39;fand-Tsetlin algebra is extended to a maximally commutative one.

Samuel P. Ferguson

The Hales program to prove the Kepler conjecture on sphere packings consists of five steps, which if completed, will jointly comprise a proof of the conjecture. We carry out step five of the program [outlined in math.MG/9811073], a proof that the local density of a certain combinatorial arrangement, the pentahedral prism, is less than that of the face-center

Thomas C. Hales

An earlier paper describes a program to prove the Kepler conjecture on sphere packings. This paper carries out the second step of that program. A sphere packing leads to a decomposition of $R^3$ into polyhedra. The polyhedra are divided into two classes. The first class of polyhedra, called quasi-regular tetrahedra, have density at most that of a regular tet

Thomas C. Hales

We describe a program to prove the Kepler conjecture on sphere packings. We then carry out the first step of this program. Each packing determines a decomposition of space into Delaunay simplices, which are grouped together into finite configurations called Delaunay stars. A score, which is related to the density of packings, is assigned to each Delaunay sta

M. Carvalho, J. A. Helayel-Neto, M. W. de Oliveira

We analyse the structure of N=1 and N=2 supersymmetric non-linear sigma-models built up with a pair of real superfields defined in the superspace of Atiyah-Ward space-time. The geometry arising has new features such as the existence of a locally product structure (N=1 case) and a set of automorphisms of the tangent space that is isomorphic to the split-quate

D. G. C. McKeon, T. N. Sherry

An SO(4) gauge invariant model with extended field transformations is examined in four dimensional Euclidean space. The gauge field is $(A^μ)^{αβ} = 1/2 t^{μνλ} (M^{νλ})^{αβ}$ where $M^{νλ}$ are the SO(4) generators in the fundamental representation. The SO(4) gauge indices also participate in the Euclidean space SO(4) transformations giving the extended fie

P. West

In this review we show that a Clifford algebra possesses a unique irreducible representation; the spinor representation. We discuss what types of spinors can exist in Minkowski space-times and we explain how to construct all the supersymmetry algebras that contain a given space-time Lie algebra. After deriving the irreducible representations of the superymme

Ernest Baver, Doron Gepner, Umut Gursoy

For each lattice one can define a free boson theory propagating on the corresponding torus. We give an alternative definition where one employs any automorphism of the group $M^*/M$. This gives a wealth of conformal data, which we realize as some bosonic theory, in all the `regular&#39; cases. We discuss the generalization to affine theories. As a byproduct,

Bang-Rong Zhou

Dynamical spontaneous breaking of some discrete symmetries including special parities and time reversal and their restoration at finite temperature T are researched in 3D Gross-Neveu model by means of Schwinger-Dyson equation in the real-time thermal field theory in the fermion bubble diagram approximation. When the momentum cut-off $Λ$ is large enough, the

W. S. l&#39;Yi

By solving the equations of motion of massive $p$-form potential in Anti-de-Sitter space and using the $AdS/CFT$ correspondence of Maldacena, the generating functional of two-point correlation functions of the currents is obtained. When the mass parameter vanishes the result agrees with the known massless case.

Andrea Gregori

We investigate the non-perturbative equivalence of some heterotic/type IIA dual pairs with N=2 supersymmetry. We compute R2-like corrections, both on the type IIA and on the heterotic side. The coincidence of their perturbative part provides a test of duality. The type IIA result is then used to predict the full, non-perturbative correction to the heterotic

R. D. Peccei

This summary is organized into four parts. In the first section (News) I discuss the SuperKamiokande results on atmospheric neutrino oscillations, as well as recent results from cosmology. The second section (Refinements) focuses on electroweak tests, recent results in the flavor sector and in probing QCD, as well as searches for new particles. The third sec

K. S. Babu, Christopher Kolda

We show that the branching ratio R_{b/tau}=BR(h^0->bb)/BR(h^0->tau tau) of the Higgs boson h^0 may usefully differentiate between the Higgs sectors of the Minimal Supersymmetric Standard Model (MSSM) and non-supersymmetric models such as the Standard Model or its two Higgs doublet extensions. Although at tree level R_{b/tau} is the same in all these models,

E. R. Berger

This report discusses some results on differential cross sections for high energy and small momentum transfer elastic hadron-hadron scattering in QCD, using a functional integral approach. In particulary a matrix cumulant expansion for the vacuum expectation values of lightlike Wegner-Wilson loops, which governs the hadronic amplitudes, is presented. The cum

E. N. Bukina, V. M. Dubovik, V. S. Zamiralov

It is shown that the baryon magnetic moment descriptions in the frameworks of the chiral model ChPT and the quark soliton $χQSM $ one are practically identical. The main difference from the traditional unitary symmetry models proves to be in terms due to the pionic current contribution into the magnetic moments of nucleons and in the prediction for the $Λ$ m

B. G. Sidharth

There have been two significant recent findings. One is a culmination of the Superkamiokande experiments, which demonstrate Neutrino oscillation and therefore a non-zero mass. The other is the finding that the universe will continue to expand without declaration based on distant supernovae observations. At the very least these two findings call for a review

V. N. Baier, V. M. Katkov

Theory of the transition radiation and the transition pair creation is developed in the frame of QED. The spectral-angular distributions of probability of the transition radiation and of the transition pair creation are found. The total energy losses of and the total probability of pair creation are calculated and analyzed. Features of radiation and pair cre

Sh. Matsumoto, M. Yoshimura

Pair annihilation of heavy stable particle that occurs in the early universe is investigated, and quantum kinetic equation for the momentum distribution of the annihilating particle is derived, using the influence functional method. A bosonic field theory model is used to describe the pair annihilation in the presence of decay product particles making up a t

E. Accomando, R. Arnowitt, B. Dutta

At the Tevatron, the most promising channel to detect supersymmetry is three leptons plus missing energy, where the leptons are $e$&#39;s and/or $μ$&#39;s. This final state appears from the production of chargino and second lighetst neutralino. However in grand unified models with universal scalar masses at the grand unified scale, this final state mostly co

Johannes Blümlein, Edward Boos, Alexander Kryukov

A compilation is given of the pair production cross sections for scalar and vector leptoquarks in the kinematic range of the hadron colliders Tevatron and LHC.

I T Drummond, R R Horgan

We show how string breaking on the lattice, treated as a mixing effect, can be related to decay rates for heavy quark systems. We use this to make a preliminary calculation of the energy split at maximum mixing for static quarks in QCD from the decay rate for $Υ(4S)\to B{\bar B}$. We extend the calculation to achieve rough estimates for the contributions of

Bernd Surrow

The OPAL experiment at LEP has performed a variety of measurements of photon-photon and electron-photon scattering at the electron-positron collider LEP to gain a deeper insight into the structure of the photon and its interactions. This review presents a summary of these results.