Erlangen 2026 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 7: Nuclear Astrophysics I

HK 7.3: Vortrag

Montag, 16. März 2026, 17:00–17:15, PHIL A 602

Experimental Studies of Proton Capture Reactions on Stable Rb Isotopes — •Svenja Wilden, Benedikt Machliner, Martin Müller, and Andreas Zilges — University of Cologne, Institute for Nuclear Physics, Germany

The p nuclei - stable neutron-deficient isotopes not produced via neutron-capture - are synthesized through photodisintegration reactions in the γ process. Since many of the relevant reactions involve unstable nuclei and cannot be measured directly, Hauser-Feshbach calculations are essential, and experimental data are needed to constrain the nuclear inputs. Proton-induced reactions therefore play a central role in improving γ-process models.

In this work, the cross sections for the ⁸⁵Rb(p,γ)⁸⁶Sr and ⁸⁷Rb(p,γ)⁸⁸Sr reactions were measured using the in-beam method at the HORUS spectrometer at the University of Cologne. The results extend the database of proton-capture reactions around A≈85, and the ⁸⁷Rb study nearly completes the systematic investigation of the stable N=50 isotones [1].

Comparisons with Hauser-Feshbach calculations show significant deviations for both isotopes, indicating deficiencies in the proton optical model potential, while variations in nuclear level densities and γ-strength functions have only minor effects. The new data provide constraints for improving statistical-model predictions and refining reaction rates.

Supported by the DFG (ZI 510/12-1).

[1] S. Wilden et al., Eur. Phys. J. A 61 (2025) 142.

Keywords: gamma process; p process; in-beam method