Browsing by Author "Adera, Gashaw Bekele"

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    Relativistic distorted wave analysis of neutrino-induced strange particle production on nuclei
    (Stellenbosch : Stellenbosch University, 2014-12) Adera, Gashaw Bekele; Van der Ventel, Brandon Izak Samuel; Phillips, Daniel R.; Stellenbosch University. Faculty of Science. Dept. of Physics.
    ENGLISH ABSTRACT: See fulltext for abstract.
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    Strange particle production via the weak interaction
    (Stellenbosch : University of Stellenbosch, 2009-03) Adera, Gashaw Bekele; Van der Ventel, B. I. S.; Hillhouse, G. C.; University of Stellenbosch. Faculty of Science. Dept. of Physics.
    In this thesis a general relativistic formalism for neutrino-induced weak production of strange particles is presented. In our formalism it is shown that the differential cross section is constructed as a contraction between a leptonic tensor and a hadronic tensor. The electroweak theory of Glashow, Salam and Weinberg is used to calculate the leptonic tensor exactly. The hadronic current is determined from the newly derived general form of the weak hadronic current which is expressed in terms of eighteen invariant amplitudes that parametrize the hadron vertex. The Born diagram is used to approximate the unknown hadronic vertex and the numerical calculation is made by evaluating the tree diagrams in terms of standard weak form factors and the strong coupling constants in the framework of the Cabibbo theory and SU(3) symmetry. The investigation is made for charged current reactions in terms of the angular distribution of the differential cross section with respect to the outgoing kaon angle and the results are discussed.
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    Strange-particle production via the weak interaction
    (2010) Adera, Gashaw Bekele; Van Der Ventel B.I.S.; Van Niekerk D.D.; Mart T.
    The differential cross sections for the neutrino-induced weak charged current production of strange particles in the threshold energy region are presented. The general representation of the weak hadronic current is newly developed in terms of eighteen unknown invariant amplitudes to parametrize the hadron vertex. The Born-term approximation is used for the numerical calculations in the framework of the Cabibbo theory and SU(3) symmetry. For unpolarized octet baryons four processes are investigated, whereas in the case of polarized baryons only one process is chosen to study the sensitivity of the differential cross section to the various polarizations of the initial-state nucleon and the final-state hyperon. © 2010 The American Physical Society.