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Call number: LD2668 .T4 1986 T56 / Master of Science / Physics

It is important that accurate estimates of crew exposure to radiation are obtained for future long - term space missions. To predict the radiation environment, a few space radiation transport codes exist, all of which use basic nuclear cross section information for transport of radiation through materials. Little theoretical and experimental work has been conducted on reactions induced by the electromagnetic (EM) force, especially with regard to di?erential cross sections. Therefore, radiation transport codes have typically neglected to incorporate EM nuclear collision cross sections. EM cross sections for single nucleon removal have been included in some radiation codes, but better values can be obtained by using an energy dependent branching ratio. Most previous theoretical and experimental work has been devoted to total cross sections. Therefore, the energy dependent branching ratios presented can be extensively compared to past theory and experiment. Such comparisons indicate that using energy dependent branching ratios yield better estimates of total cross sections. Differential cross sections for electromagnetic dissociation in nuclear collisions are calculated for the first time. In order to be useful for three - dimensional transport codes, these cross sections have been calculated in both the projectile and lab frames. The formulas for these cross sections are such that they can be immediately used in space radiation transport codes. Only a limited amount of data exists, but the comparison between theory and experiment is good.

Thèse de doctorat : Physique : Metz : 2001. / Thèse : 2001METZ035S. Bibliogr. p. 103-108.

Thèse de doctorat : Physique : Physique atomique et moléculaire : Metz : 2006. / Thèse soutenue sur ensemble de travaux. Bibliogr. p. 119-125. Annexes.

Thèse de doctorat : Physique : Metz : 2008. / Thèse soutenue sur ensemble de travaux (s'il y a lieu). Bibliogr. f. 115-120.

Thèse de doctorat : Physique nucléaire : Strasbourg 1 : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. 157-168.

Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009. / Committee Chair: M. Raymond Flannery; Committee Member: Daniel Goldman; Committee Member: Dewey H. Hodges; Committee Member: Li You; Committee Member: Turgay Uzer. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Studying the annihilation of e+e- into hadrons is of great interest in the search for physics beyond the standard model. The cross sections of specific hadronic channels can be used in precise test of the Standard Model, or to estimate the anomalous muon magnetic moment, for which there are discrepancies between theory and experiment. This thesis focuses on one particular hadronic channel, e+e- → ηπ+π- with the final state π+π-γγ. As background, the reaction e+e- → π+π-π0 is chosen. By simulations using the Monte Carlo event generator PHOKHARA and the data analysis framework ROOT, the feasibility of detecting the aforementioned reaction with the detector KLOE at the electron-positron collider DAΦNE is studied. The detector acceptance and expected number of events is evaluated both for the signal and the background. An analysis program that can be used for feasibility studies of e+e- → ηπ+π- was written. The simulations indicate that the signal significance from an experiment at DAΦNE would be 2.4σ and thus lower than the confidence level required for detection. A definitive statement can however only be made after further investigations into minimizing the background and studies of additional final states with other decays of the η-meson and their corresponding background reactions. / I sökandet efter fysik bortom standardmodellen är studier av elektron-positron-annihilation till hadroner av stort intresse. Tvärsnitten för specifika hadroniska kanaler kan användas för precisa tester av standardmodellen, eller för att uppskatta myonens anomala magnetiska moment, vars teoretiska värde avviker från det experimentella. Detta examensarbete fokuserar på en specifik hadronisk kanal, e+e- → ηπ+π- med sluttillståndet π+π-γγ. Som bakgrund väljs reaktionen e+e- → π+π-π0. Med hjälp av simulationer byggda på den Monte Carlo-baserade händelsegeneratorn PHOKHARA, och ROOT, ett ramverk för dataanalys, studeras om det är genomförbart att detektera den ovan nämnda reaktionen med detektorn KLOE vid acceleratorn DA\(\Phi\)NE. Detektoracceptansen och det förväntade antalet händelser utvärderas både för signalen och bakgrunden. Ett analysprogram som skulle kunna användas för andra genomförbarhetsstudier för e+e- → ηπ+π- har skrivits. Simulationerna visar signifikansen för signal från experiment vid DAΦNE skulle vara 2.4σ, vilket är lägre än den konfidensnivå som krävs för att reaktionen med säkerhet ska kunna detekteras. Dock kan ett slutgiltigt besked ges först efter att möjligheten att ytterligare minska antalet bakgrundshändelser har undersökts och fler sluttillstånd med andra η-sönderfall och motsvarande bakgrundsreaktioner har studerats.