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The Global ETD Search service is a free service for researchers
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Showing 31 to 34 of 34 (0.035 seconds)Spelling suggestions: "subject:"hyperons"" "subject:"operons""
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Electromagnetic production of mesons and hyperons from nucleiNsio Nzundu, Tony 12 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2007. / A relativistic plane wave model is developed for electromagnetic production of unbound
hyperons with free kaons from nuclei. The differential cross section is expressed as a
contraction of leptonic and hadronic tensors. The leptonic tensor is constructed by using
the helicity representation of a free Dirac spinor. A model for the corresponding elementary
process is used to calculate the hadronic tensor, in which the hadronic current operator
Jˆμ is written as a linear combination of six invariant amplitudes and six Lorentz and
gauge invariant quantities. The kinematics for this process is assumed to be a quasi-free
process i.e., the electron interacts with only one bound nucleon inside the nucleus. The
bound state wavefunction of the bound nucleon is calculated within the framework of the
relativistic mean-field approximation. The unpolarized differential cross section for the K+
electroproduction process, e + A −→ e + K+ + A + Aresidual is calculated as a function of
the hyperon scattering angle.
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Uma investigação sobre o decaimento semileptônico do Cascata Neutro no caso Muônico e a sua observaçãoGomes, Ricardo Avelino 14 July 2005 (has links)
Orientador: Carlos Ourivio Escobar / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-05T00:48:53Z (GMT). No. of bitstreams: 1
Gomes_RicardoAvelino_D.pdf: 22856845 bytes, checksum: ff49da476ee952e261dde1c21ce27f56 (MD5)
Previous issue date: 2005 / Resumo: Apresentamos uma investigação sobre o decaimento semileptônico ?0??+µ - ?µ. Observamos este decaimento pela primeira vez com nove eventos identificados, utilizando para tal a linha de feixe e os detectores do experimento KTeV no Fermilab. O decaimento é normalizado pelo modo ?0??+e- ?e, resultando em uma razão das taxas de decaimento G(?0??+µ - ?µ)/G(?0??+e- ?e) igual a ( 1,8+0,7-0,5(estat.) ± 0,2(sist.) ) x 10-2 com 68,27% C.L., que se tomou a medida oficial da colaboração KTeV: Em uma análise independente, também utilizamos o decaimento dominante ?0? ?p0(???p-) como modo de normalização, o que corroborou o resultado principal. Realizamos ainda, uma nova medida da razão de ramificação do modo ?0??+e- ?e com base em 1139 eventos e normalizada pelo decaimento ?0??p0(???p-). Os resultados estão em pleno acordo com o modelo a quarks com simetria SU(3) de sabor / Abstract: We report an investigation of the semileptonic decay ?0??+µ - ?µ. This decay was observed for the first time with nine identified events using the KTeV beam line and detector at Fermilab. The decay is normalized to the ?0 beta decay mode and yields a value for the ratio of decayrates G(?0??+µ - ?µ)/G(?0??+e- ?e) igual a ( 1,8+0,7-0,5(stat.) ± 0,2(syst.) ) x 10-2 at the 68,27% confidence level, being the official measurement of KTeV Collaboration. We also used the dominant decay ?0? ?p0(???p-) as normalization mode in an independent analysis which corroborated with the main result. In addition, a new measurement of the ?0??+e- ?e branching ratio is presented, based on 1139 events and normalized to the ?0??p0(???p-) decay mode. The results are in agreement with the SU(3) flavor symmetric quark model / Doutorado / Física das Particulas Elementares e Campos / Doutor em Ciências
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The Strong Potential of ΛΛ Femtoscopy at HADESBohman, Malin January 2022 (has links)
The aims of this thesis project have been to determine the feasibility of hyperon reconstruction utilizing a newly developed and implemented vertex fitter based on the Lagrange multiplier method. This was achieved through simulation and subsequent analysis of the reaction specified below, detailing the production of Λ-hyperon and K+ -meson pairs from proton-proton collisions. 𝑝(4.5𝐺𝑒𝑉)𝑝 → ΛΛ𝐾+𝐾+ This reaction channel provides a more complicated topology than previous benchmark studies of the fitter performance and is of interest as it enables studies of the strong ΛΛ interaction via the femtoscopy method. For this reason, measurements of this reaction channel were among the physics goals of the HADES beam time taking place in February 2022. As such, this study has provided insight into the feasibility of performing a femtoscopy analysis on this data by reconstructing the Λ-pair using the fitter. The obtained results provide the Λ-pair reconstruction efficiency and purities based on the lower limit of expected events collected during this beamtime. As for the fitter performance, it was found from the reconstructed kinematics of the Λ-pair that the fitter can effectively remove background over most of the kinematic region. However, for low relative momentum, combinatorial background becomes especially prominent. As this region is of interest in a femtoscopy study, it has been identified as especially challenging for the developed analysis procedure.
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| 34 |
Compact Star Equation of State with Temperature and Magnetic Field EffectsPeterson, Jeffrey L. 21 November 2022 (has links)
No description available.
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