3,389 research outputs found

    High pt Measurements at the CERN SPS

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    The current experimental situation concerning high pt observables at the CERN SPS is reviewed. Recent data from the NA45, NA49 and NA57 collaborations are discussed and compared to earlier measurements by WA98 and NA45 at the same center-of-mass energies, as well as to measurements at the higher energies by the RHIC experiments. The observables include new p+p, A+A spectra, nuclear modification factors (R_AA, R_CP), two particle azimuthal correlations, and baryon to meson ratios at moderately high pt. Generally, the interpretation of the SPS data suffers from the lack of reliable baseline measurements (p+p and p+A). However, the overall picture that is emerging suggests that already at SPS energies medium effects similar to those observed at RHIC are present.Comment: Invited plenary talk at the Hard Probes Conference Asilomar, CA, June 9-16, 2006, to be published in Nucl. Phys.

    Criptorquia - estudo comparativo

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    Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Pediatria

    Adjoint algebraic entropy

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    The new notion of adjoint algebraic entropy of endomorphisms of Abelian groups is introduced. Various examples and basic properties are provided. It is proved that the adjoint algebraic entropy of an endomorphism equals the algebraic entropy of the adjoint endomorphism of the Pontryagin dual. As applications, we compute the adjoint algebraic entropy of the shift endomorphisms of direct sums, and we prove an Addition Theorem for the adjoint algebraic entropy of bounded Abelian groups. A dichotomy is established, stating that the adjoint algebraic entropy of any endomorphism can take only values zero or infinity. As a consequence, we obtain the following surprising discontinuity criterion for endomorphisms: every endomorphism of a compact abelian group, having finite positive algebraic entropy, is discontinuous.Comment: 27 page

    CPV tests with rare kaon decays

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    The K_S \to pi+/- e+ e- decay mode has been investigated using the data collected in 2002 by the NA48/1 collaboration. With about 23k signal events and 59k K_L \to pi+ pi- pi0_D normalization decays, the K_S \to pi+ pi- e+ e- branching ratio was determined. This result is also used to set an upper limit on the presence of E1 direct emission in the decay amplitude. The CP-violating asymmetry has been also measured. We report on measurements of the rare decays K +/- \to pi+/- e+ e- and K+/- \to pi+/- mu+ mu- . The full NA48/2 data set was analyzed, leading to more than 7200 reconstructed events in the electronic and more than 3000 events in the muonic channel, the latter exceeding the total existing statistics by a factor of four. For both channels the selected events are almost background-free. From these events, we have determined the branching fraction and form factors of K+/- \to pi+/- e+ e- using different theoretical models. Our results improve the existing world averages significantly. In addition, we measured the CP violating asymmetry between K+ and K- in this channel to be less than a few percent.Comment: 4 pages, 1 figure, To appear in the proceedings of IX International Conference on Hyperons, Charm and Beauty Hadrons (BEACH2010), Perugia, Italy, 21-26 June 201

    Extracting short-distance physics from K_{L,S} -> pi0 e+ e- decays

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    We present a new analysis of the rare decay K_L -> pi0 e+ e- taking into account important experimental progress that has recently been achieved in measuring K_L -> pi0 gamma gamma and K_S -> pi0 e+ e-. This includes a brief review of the direct CP-violating component, a calculation of the indirect CP-violating contribution, which is now possible after the measurement of K_S -> pi0 e+ e-, and a re-analysis of the CP conserving part. The latter is shown to be negligible, based on experimental input from K_L -> pi0 gamma gamma, a more general treatment of the form factor entering the dispersive contribution, and on a comparison with the CP violating rate, which can now be estimated reliably. We predict B(K_L -> pi0 e+ e-) = (3.2 +1.2 -0.8) 10^{-11} in the Standard Model, dominated by CP violation with a sizable contribution (~40%) from the direct effect, largely through interference with the indirect one. Methods to deal with the severe backgrounds for K_L -> pi0 e+ e- using Dalitz-plot analysis and time-dependent K_L-K_S interference are also briefly discussed.Comment: 24 pages, 6 figures; v2: minor modifications, published versio

    Éxito de la alimentación de Lutzomyia evansi (Diptera: Psychodidae) expuestos experimentalmente a reservorios mamíferos pequeños en un foco endémico de Leishmania chagasi en el norte de Colombia

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    Lutzomyia evansi is the vector of Leishmania chagasi in northern Colombia. Differences in feeding success were revealed, when this phlebotomine sand fly was fed on five species of small mammal hosts from an endemic focus of visceral leishmaniasis. In each trial, 50 female sand flies were provided access to similar-sized depilated areas of the hind foot of each of 44 individual mammals and allowed to feed for 30 minutes. The number of engorged sand flies was counted at the end of each trial and compared among host species by analysis of variance and Tukey's multiple comparisons test. Sand flies fed least successfully on Sciurus granatensis, a common squirrel in the endemic area. It has not been found infected with L. chagasi. Intermediate numbers of sand flies engorged on Heteromys anomalus and Zygodontomys brevicauda, but these two mammals have not been found infected with L. chagasi and are not expected to be important in transmission. Sand flies fed most successfully on Didelphis marsupialis and Proechimys canicollis. These are the two most abundant mammals in the endemic area and frequently are infected. Results provided further evidence that these two species are the wild mammals with the greatest impact on transmission of L. chagasi in northern Colombia.Un método sencillo de laboratorio reveló diferencias en el éxito de alimentación de Lutzomyia evansi, el vector de Leishmania chagasi en el norte de Colombia, cuando se alimentó sobre cinco especies de pequeños mamíferos de un foco endémico de leishmaniasis visceral, en los que éstos podrían actuar como reservorios. En cada ensayo, a 50 flebótomos hembra se les permitió alimentarse durante 30 minutos sobre un área similar de piel depilada de la pata posterior en 44 mamíferos. El número de flebótomos alimentados se comparó entre especies a través de un análisis de varianza y de la prueba de Tukey de comparaciones múltiples. Los flebótomos escasamente se alimentaron sobre Sciurus granatensis, una ardilla común en el área endémica que no se ha encontrado infectada con Leishmania chagasi. En otros dos mamíferos que hasta el presente han sido negativos para L. chagasi (Heteromys anomalus y Zygodontomys brevicauda), los flebótomos se alimentaron en bajos números. En cambio, los flebótomos se alimentaron en altas proporciones sobre Didelphis marsupialis y Proechimys canicollis, los dos mamíferos más abundantes en el área endémica y que se hallan infectados con L. chagasi. Los resultados aportaron evidencia adicional que estas dos especies de mamíferos silvestres serían una fuente de sangre común para los flebótomos y que, por lo tanto, pueden tener gran impacto sobre la transmisión de L. chagasi en el norte de Colombia

    Qcmpi: A Parallel Environment for Quantum Computing

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    QCMPI is a quantum computer (QC) simulation package written in Fortran 90 with parallel processing capabilities. It is an accessible research tool that permits rapid evaluation of quantum algorithms for a large number of qubits and for various "noise" scenarios. The prime motivation for developing QCMPI is to facilitate numerical examination of not only how QC algorithms work, but also to include noise, decoherence, and attenuation effects and to evaluate the efficacy of error correction schemes. The present work builds on an earlier Mathematica code QDENSITY, which is mainly a pedagogic tool. In QCMPI, the stress is on state vectors, in order to employ a large number of qubits. The parallel processing feature is implemented by using the Message-Passing Interface (MPI) protocol. Codes for Grover's search and Shor's factoring algorithms are provided as examples. A major feature of this work is that concurrent versions of the algorithms can be evaluated with each version subject to alternate noise effects, which corresponds to the idea of solving a stochastic Schr\"{o}dinger equation.Comment: Package webpage http://www.pitt.edu/~tabakin/QCMP

    Algebraic entropy in locally linearly compact vector spaces

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    We introduce algebraic entropy for continuous endomorphisms of locally linearly compact vector spaces over a discrete field, as a natural extension of the algebraic entropy for endomorphisms of discrete vector spaces studied in Giordano Bruno and Salce (Arab J Math 1:69\u201387, 2012). We show that the main properties continue to hold in the general context of locally linearly compact vector spaces, in particular we extend the Addition Theorem

    Spin-1 resonance contributions to the weak Chiral Lagrangian: the vector field formulation

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    We use the Vector formulation to evaluate vector and axial-vector exchange contributions to the O(p^4) weak Chiral Lagrangian. We recover in this framework the bulk of the contributions found previously by Ecker et al. in the antisymmetric formulation of vectors and axial-vectors, but new interesting features arise: i) most of our results are independent of Factorization and ii) novel contributions to non-leptonic kaon decays, proper of this formulation and phenomenologically interesting, are found. The phenomenological implications for K -> pi pi (pi) and radiative (anomalous and non-anomalous) non-leptonic kaon decays are thus investigated and found particularly relevant.Comment: 34 pages, plain LaTeX file, uses rotating.sty also include

    The Version-2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–Present)

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    The Global Precipitation Climatology Project (GPCP) Version-2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.58 latitude 3 2.58 longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit satellite microwave data, geosynchronous-orbit satellite infrared data, and surface rain gauge obser-vations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The dataset is extended back into the prem-icrowave era (before mid-1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the rain gauge analysis. The dataset archive also contains the individual input fields, a combined satellite estimate, and error estimates for each field. This monthly analysis is the foundation for the GPCP suite of products, including those at finer temporal resolution. The 23-yr GPCP climatology is characterized, along with time and space variations of precipitation. 1
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