Speaker
Ann-Cecilie Larsen
(University of Oslo)
Description
All elements found in our Universe, except for the very lightest ones, have been created during stars' lives and/or deaths.
Burbidge, Burbidge, Fowler and Hoyle pointed out the slow neutron-capture and the rapid neutron-capture process to be the main contributors for producing elements from iron to uranium.
On August 17, 2017, the LIGO and Virgo gravitational-wave detectors measured, for the first time, a direct signal from two colliding neutron stars.
Follow-up measurements with telescopes sensitive to electromagnetic radiation confirmed that the r-process had indeed taken place in the collision (Ref.~\cite{Pian2017}).
Hence, a long-standing question in nuclear astrophysics was solved; at least one astrophysical r-process site is now identified.
However, the uncertain nuclear-physics input remains a huge obstacle in modeling the r-process yields in large-scale nucleosynthesis network calculations.
The r-process inevitably involves highly neutron-rich nuclei, where there is a severe lack of relevant nuclear data such as masses, beta-decay rates and neutron-capture cross sections.
Well away from the valley of stability, different theoretical predictions for neutron-capture rates may vary with several orders of magnitude.
In this talk, a recently developed method to address this issue is presented: the beta-Oslo method provides data on the nuclear level density and average gamma-decay strength of moderately neutron-rich nuclei.
These quantities are crucial input for calculations of neutron-capture rates, which in turn play a key role in a "cold" r-process scenario.
The beta-Oslo method presents a first step towards constraining neutron-capture rates of importance to the r-process.
References
E.~M.~Burbidge \textit{et al.}, Rev. Mod. Phys. \textbf{29}, 547 (1957).
B.~P.~Abbott \textit{et al.}, Phys. Rev. Lett. \textbf{119}, 161101 (2017).
E. Pian \textit{et al.}, \textit{Nature} \textbf{551}, 67 (2017).
M. Arnould, S. Goriely, and K. Takahashi, Phys. Rep. {\bf 450}, 97 (2007).
A.~Spyrou \textit{et al.}, Phys. Rev. Lett. \textbf{113}, 232502 (2014).
S.~N.~Liddick \textit{et al.}, Phys. Rev. Lett. \textbf{116}, 242502 (2016).
Primary author
Ann-Cecilie Larsen
(University of Oslo)
Co-authors
Artemis Spyrou
(NSCL/MSU)
Magne Guttormsen
(University of Oslo)
Sean N. Liddick
(Michigan State University)
