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HK: Fachverband Physik der Hadronen und Kerne
HK 62: Nuclear Astrophysics V
HK 62.5: Vortrag
Donnerstag, 14. März 2024, 17:00–17:15, HBR 14: HS 4
Transition frequency measurements in 46−50Ti+ of astrophysical interest at COALA — •Julien Spahn, Kristian König, Tim Lellinger, Wilfried Nörtershäuser, and Tim Ratajczyk — Institut für Kernphysik, TU Darmstadt, 64289 Darmstadt, Germany
A long standing question of cosmology is if fundamental physical constants, like the fine structure constant α, are in fact constant or vary with time, as proposed by different theories expanding the standard model [1]. To investigate this behavior, the study of the fine-structure splitting of atomic levels (∝ α2), within the absorption lines caused by gas clouds in the light emitted by quasars, has been proposed [2]. Especially transition metals lighter than Fe and hence produced through fusion, like Ti, are of particular interest, since they are produced in first generation stars and thus give access to the very early state of the universe 12 billion years ago.
Such studies require a precise knowledge of absolute transition frequencies at an accuracy better than 10−4 Å, which can be achieved using collinear laser spectroscopy, as demonstrated on numerous stable and short-lived isotopes. Three transitions in 46−50Ti from the 3d2(3F)4s 4F ground state to the 3d2(3F)4p 4G state have been investigated at COALA at TU Darmstadt. This contribution will present our latest results obtained using a versatile laser ablation source, which will allow us to investigate other transitions of interest in the future.
This project is supported by BMBF under contract 05P21RDFN1.
[1] J.-P. Uzan, Reviews of Modern Physics, vol. 75, 2003.
[2] D. J. Mortlock et al., Nature, vol. 474, 2011.
Keywords: Laser spectroscopy; Isotopic shift; Nuclear structure; Atomic structure; Nuclear astrophysics