Mesure du paramètre de corrélation angulaire bêta-neutrino dans la désintégration de l'6He

Abstract : The subject of this work is the data analysis of the LPCTrap experiment which occured in 2008. The goal was to measure the b-v angular correlation coefficient, abv, in the 6He decay at a 0.5% precision level. Evidences of a discrepancy between the experimental value of abv and the prediction of the Standard Model (SM) would mean the existence of a vector current in the weak decay of 6He. This discovery would question the V−A structure used to described the weak intraction in the SM. A Paul trap is used to confine 6He+ ions almost at rest in a very small volume in order to have a decay source as well defined as possible. The emitted particle and 6Li++ ion are detected in coincidence by detectors located around the trap. abv is determined from a comparaison between the experimental and a Monte Carlo simulated distributions of the time of flight of the recoiling ions. During this work, a simulation based on GEANT4 has been developed, taking into account all the experimental effects which are likely to contribute to the systematic error of the a bv estimation. A special focus has been put on the electron scattering modelling. Despite a sufficient experimental statistics and an efficient simulation, a correct estimation was not achieved due to a malfunction of the ion detector. An exploratory statistical study has been undertaken in order to accurately specify the sensitivity level of the measurement performed with the LPCTrap apparatus in testing the hypotheses of the SM. The tools developed in this work will be used to analyze future experiments.
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https://tel.archives-ouvertes.fr/tel-00626170
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Submitted on : Friday, September 23, 2011 - 4:30:51 PM
Last modification on : Tuesday, February 5, 2019 - 12:12:07 PM
Long-term archiving on : Saturday, December 24, 2011 - 2:25:35 AM

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  • HAL Id : tel-00626170, version 1

Citation

P. Velten. Mesure du paramètre de corrélation angulaire bêta-neutrino dans la désintégration de l'6He. Physique Nucléaire Théorique [nucl-th]. Université de Caen, 2011. Français. ⟨tel-00626170⟩

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