Extensions and degenerations of spectral triples

For a unital C*-algebra A, which is equipped with a spectral triple and an extension T of A by the compacts, we construct a family of spectral triples associated to T and depending on the two positive parameters (s,t). Using Rieffel's notation of quantum Gromov-Hausdorff distance between compact quantum metric spaces it is possible to define a metric on this family of spectral triples, and we show that the distance between a pair of spectral triples varies continuously with respect to the parameters. It turns out that a spectral triple associated to the unitarization of the algebra of compact operators is obtained under the limit - in this metric - for (s,1) -> (0, 1), while the basic spectral triple, associated to A, is obtained from this family under a sort of a dual limiting process for (1, t) -> (1, 0). We show that our constructions will provide families of spectral triples for the unitarized compacts and for the Podles sphere. In the case of the compacts we investigate to which extent our proposed spectral triple satisfies Connes' 7 axioms for noncommutative geometry.Comment: 40 pages. Addedd in ver. 2: Examples for the compacts and the Podle`s sphere plus comments on the relations to matricial quantum metrics. In ver.3 the word "deformations" in the original title has changed to "degenerations" and some illustrative remarks on this aspect are adde

RESEARCH ON THE REALIZATION OF BIOCOMPOSITE ECOFERTILIZING GRANULAR MATERIALS BASED ON PEAT

Lately, fertilizer researches focuses on reducing the negative impact of using it on the environment and consumers, and finding new, less costly fertilizer sources.The application of organo-mineral fertilizers is a better approach to sustaining soil fertility and crop yield than applying only chemical or organic fertilizers.The paper presents the results of the researches regarding the realization and characterization of granular biocomposite biofertilizers based on peat.In order to improve the fertilizer role of the peat, the used recipe contains urea as a source of nitrogen monoammonium phosphate (MAP) as a source of phosphorus and nitrogen, sugar beet molasses as a source of organic nitrogen, potassium and vitamins, protein hydrolyzate, as the source of protein and other microelements

Colorless States in Perturbative QCD: Charmonium and Rapidity Gaps

We point out that an unorthodox way to describe the production of rapidity gaps in deep inelastic scattering, recently proposed by Buchm\"uller and Hebecker, suggests a description of the production of heavy quark bound states which is in agreement with data. The approach questions the conventional treatment of the color quantum number in perturbative QCD.Comment: 14 pages, plain Latex, 9 postscript figures included. Uses epsf.sty. Postscript file of paper with figures also available at http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-919.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-919.ps.

pQCD Physics of multiparton interactions

We study production of two pairs of jets in %hard hadron--hadron collisions in view of extracting contribution of {\em double hard interactions} of three and four partons ($3\to4$, $4\to4$). Such interactions, in spite of being power suppressed at the level of the total cross section, become comparable with the standard hard collisions of two partons, $2\to4$, in the {\em back-to-back kinematics} when the transverse momentum imbalances of two pairing jets are relatively small. We express differential and total cross sections for two-dijet production in double parton collisions through the generalized two-parton distributions, $_2$GPDs \cite{BDFS1}, that contain large-distance two-parton correlations of non-perturbative origin as well as small-distance correlations due to parton evolution. We find that these large- and small-distance correlations participate in different manner in 4-jet production, and treat them in the leading logarithmic approximation of pQCD that resums collinear logarithms in all orders. A special emphasis is given to $3\to4$ double hard interaction processes that occur as an interplay between large- and short-distance parton correlations and were not taken into consideration by approaches inspired by the parton model picture. We demonstrate that the $3\to4$ mechanism, being of the same order in \as as the $4\to4$ process, turns out to be {\em geometrically enhanced} compared to the latter and should contribute significantly to 4-jet production. The framework developed here takes into systematic consideration perturbative $Q^2$ evolution of $_2$GPDs. It can be used as a basis for future analysis of NLO corrections to multi-parton interactions (MPI) at LHC and Tevatron colliders, in particular for improving evaluation of QCD backgrounds to new physics searches.Comment: 16 pages,4 figures Improved presentation; list of references reworked; qualitative estimate of the magnitude of different contributions in the beck-to- back region correcte

PYTHIA 6.4 Physics and Manual

The PYTHIA program can be used to generate high-energy-physics `events', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further information may be found on the PYTHIA web page: http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly deleted section heading for "Physics Processes" reinserted, affecting section numbering. Minor updates to take into account referee comments and new colour reconnection option

Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV

We present the first measurement of the inclusive three-jet differential cross section as a function of the invariant mass of the three jets with the largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96 TeV. The measurement is made in different rapidity regions and for different jet transverse momentum requirements and is based on a data set corresponding to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at the Fermilab Tevatron Collider. The results are used to test the three-jet matrix elements in perturbative QCD calculations at next-to-leading order in the strong coupling constant. The data allow discrimination between parametrizations of the parton distribution functions of the proton.Comment: 10 pages, 4 figures, 2 tables, submitted to Phys. Lett. B, corrected chi2 values for NNPD

Measurement of the dijet invariant mass cross section in proton anti-proton collisions at sqrt{s} = 1.96 TeV

The inclusive dijet production double differential cross section as a function of the dijet invariant mass and of the largest absolute rapidity of the two jets with the largest transverse momentum in an event is measured in proton anti-proton collisions at sqrt{s} = 1.96 TeV using 0.7 fb^{-1} integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The measurement is performed in six rapidity regions up to a maximum rapidity of 2.4. Next-to-leading order perturbative QCD predictions are found to be in agreement with the data.Comment: Published in Phys. Lett. B, 693, (2010), 531-538, 8 pages, 2 figures, 6 table

Quantitative Tests of Color Evaporation: Charmonium Production

The color evaporation model simply states that charmonium production is described by the same dynamics as $D \bar D$ production, {\em i.e.}, by the formation of a colored $c \bar c$ pair. Its color happens to be bleached by soft final-state interactions. We show that the model gives a complete picture of charmonium production including low-energy production by proton, photon and antiproton beams, and high-energy production at the Tevatron and HERA. Our analysis includes the first next-to-leading-order calculation in the color evaporation model.Comment: 12 pages (with embedded figures), Latex2.09, uses epsf.sty and epsfig.sty. Z-compressed postscript version also available at http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte