Open Access

Juan Carlos Zamora Cardona, Thomas Aumann, Soumya Bagchi, Esther Sabine Bönig, Margit Csatlós, Iris Dillmann, Christina Dimopoulou, Peter Egelhof, Vladimir Eremin, Tatsuya Furuno, Hans Geissel, Roman Gernhäuser, Muhsin N. Harakeh, Anna-Lena Hartig, Stoyanka Ilieva, Nasser Kalantar-Nayestanaki, Oleg A. Kiselev, Holger Kollmus, Christophor Kozhuharov, Attila Krasznahorkay, Thorsten Kröll, Maartje Kuilman, Sergey A. Litvinov, Yuri A. Litvinov, Masoud Mahjour-Shafiei, Manfred Mutterer, Daisuke Nagae, Mohammad Ali Najafi, Chiara Nociforo, Fritz Nolden, Ulrich Popp, Catherine Rigollet, Subhankar Roy, Christoph Scheidenberger, Mirko von Schmid, Markus Steck, Branislav Streicher, László Stuhl, Michael Friedrich Erhard Thürauf, Tomohiro Uesaka, Helmut Weick, John S. Winfield, Danyal Ferdinant Alexander Winters, Philip John Woods, Takayuki Yamaguchi, Ke Yue, Juzo Zenihiro

• A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment was carried out at the experimental heavy-ion storage ring (ESR) at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm ≤ 1.5°) were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79+12−11% of the energy-weighted sum rule (EWSR), which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams.