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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 61 to 64 of 64 (0.012 seconds)| 61 |
Measurement of the Branching Fraction and Search for Direct CP-Violation in the Radiative Decay B to K*Gamma with the BABAR DetectorColberg, Tilmann 18 April 2002 (has links)
Die hier vorgestellte Untersuchung des radiativen elektroschwachen "Pinguin"-Zerfalls B->K*(892)Gamma, der durch den "Schleifen"-Übergang b->sGamma stattfindet, stellt einen wichtigen Test des Standardmodells und einen Kandidaten für die Suche nach Neuer Physik dar. Der benutzte Datensatz wurde auf der Y(4S)-Resonanz mit dem BABAR-Detektor am asymmetrischen Elektron-Positron-Speicherring PEP-II des Stanford Linear Accelerator Centers (SLAC) aufgezeichnet. Die B->K*Gamma Verzweigungsverhältnisse wurden in vier K*-Zerfallskanälen gemessen. Eine Suche nach direkter CP-Verletzung im B->K*Gamma Kanal wurde ebenfalls durchgeführt. / The presented study of the radiative electroweak "penguin"-decay B->K*(892)gamma, proceeding by the b->sgamma "loop"-transition, provides an important test of the Standard Model and a candidate of the search for New Physics. The used data sample has been recorded at the Y(4S) resonance with the BABAR detector at the asymmetric electron-positron- collider PEP-II of the Stanford Linear Accelerator Center (SLAC) in California. The B->K*gamma branching fractions are measured in four K*-decay modes. A search for direct CP-violation in the B->K*gamma mode has also been carried out.
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The Effects Of Rho-omega Mixing In Radiative Vector Meson DecaysKucukarslan, Ayse 01 December 2003 (has links) (PDF)
The radiative & / #969 / & / #8594 / & / #960 / 0& / #960 / 0& / #947 / , & / #961 / & / #8594 / & / #960 / 0& / #960 / 0& / #947 / , & / #969 / & / #8594 / & / #960 / +& / #960 / & / #8722 / & / #947 / and & / #961 / & / #8594 / & / #960 / +& / #960 / & / #8722 / & / #947 / decays
are studied by adding the effect of vector meson mixing to the amplitude of
these decays. For the above decays we consider only & / #961 / & / #8722 / & / #969 / mixing. In addition
to the & / #961 / & / #8722 / & / #969 / mixing, we also analyse the contributions coming from different
intermediate states to examine the decay mechanism of these decays in a phenomenological
framework. For & / #969 / & / #8594 / & / #960 / 0& / #960 / 0& / #947 / decay, we consider the contributions
of the & / #961 / -meson and & / #963 / -meson intermediate states and of the kaon-loop, and for
the & / #961 / & / #8594 / & / #960 / 0& / #960 / 0& / #947 / decay we calculate the amplitude using the contributions of the
& / #969 / -meson and & / #963 / -meson intermediate states and pion-loop. Moreover, the radiative
& / #969 / & / #8594 / & / #960 / +& / #960 / & / #8722 / & / #947 / decay is studied by considering the contributions of & / #963 / -meson
and & / #961 / -meson intermediate states and the decay & / #961 / & / #8594 / & / #960 / +& / #960 / & / #8722 / & / #947 / is investigated by
taking into account the contributions of bremmsstrahlung, pion-loop and & / #963 / -
meson intermediate state amplitude. We also estimate the coupling constant
g& / #969 / & / #963 / & / #947 / utilizing the latest experimental value of the branching ratio & / #969 / & / #8594 / & / #960 / 0& / #960 / 0& / #947 / .
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Schwellennahe Erzeugung von Kaonen und Antikaonen in Proton-Kern-StößenScheinast, Werner 18 August 2004 (has links)
Am Schwerionensynchrotron der GSI Darmstadt wurde die Produktion von K- und pi-Mesonen in Proton-Kern-Kollisionen ("pA") experimentell untersucht. Verschiedene Targetkerne (C, Au), Strahlenergien (1.6, 2.5, 3.5 GeV) und Beobachtungswinkel (32°-64°) ergaben eine reichhaltige Systematik und gestatteten Extrapolationen auf totale Wirkungsquerschnitte. In der Arbeit werden Vergleiche der einzelnen Messungen miteinander und mit pA-Messungen anderer Gruppen angestellt und diskutiert. Die Einordnung zwischen pp- und AA-Daten und der Vergleich mit theoretischen Vorhersagen ermöglicht grundlegende Aussagen über das Verhalten von K-Mesonen in Kernmaterie, sogenannte Medium-Effekte.
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First Time Measurements of Polarization Observables for the Charged Cascade Hyperon in PhotoproductionBono, Jason S 06 June 2014 (has links)
The parity violating weak decay of hyperons offers a valuable means of measuring their polarization, providing insight into the production of strange quarks and the matter they compose. Jefferson Lab’s CLAS collaboration has utilized this property of hyperons, publishing the most precise polarization measurements for the Λ and Σ in both photoproduction and electroproduction to date. In contrast, cascades, which contain two strange quarks, can only be produced through indirect processes and as a result, exhibit low cross sections thus remaining experimentally elusive.
At present, there are two aspects in cascade physics where progress has been minimal: characterizing their production mechanism, which lacks theoretical and experimental developments, and observation of the numerous excited cascade resonances that are required to exist by flavor SU(3)F symmetry. However, CLAS data were collected in 2008 with a luminosity of 68 pb−1 using a circularly polarized photon beam with energies up to 5.45 GeV, incident on a liquid hydrogen target. This dataset is, at present, the world’s largest for meson photoproduction in its energy range and provides a unique opportunity to study cascade physics with polarization measurements.
The current analysis explores hyperon production through the γp → K+K+Ξ− reaction by providing the first ever determination of spin observables P, Cx and Cz for the cascade. Three of our primary goals are to test the only cascade photoproduction model in existence, examine the underlying processes that give rise to hyperon polarization, and to stimulate future theoretical developments while providing constraints for their parameters. Our research is part of a broader program to understand the production of strange quarks and hadrons with strangeness. The remainder of this document discusses the motivation behind such research, the method of data collection, details of their analysis, and the significance of our results.
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