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The international workshop “MNT2024 – Exploring the heavy exotic neutron-rich nuclides via multinucleon transfer reactions -” was held at RIKEN from July 2 to 5, 2024. It was co-hosted by the Wako Nuclear Science Center (WNSC) at the KEK-IPNS, the University of York (UK), the RIKEN Nishina Center for Accelerator-Based Science, and the Advanced Science Research Center at the Japan Atomic Energy Agency.This workshop focused on a new research field opened by neutron-rich nucleosynthesis using MultiNucleon Transfer (MNT) reactions.

It is believed that the elements in nature have been synthesized through various processes that occur in the universe. Among those processes, the “rapid neutron-capture process (r-process)” is considered to happen in extremely hot places with lots of neutrons. In this process, nuclei repeatedly absorb many neutrons and undergo beta decay in a short period of time, creating heavy elements up to uranium. The r-process involves the synthesis of nuclei that have significantly more neutrons compared to stable nuclei, called neutron-rich nuclei. To explore the mysteries of the r-process, researchers need to study these neutron-rich nuclei. This has led to experiments around the world using methods like nuclear fission, which splits one nucleus into two, and nuclear fragmentation, where two nuclei are smashed together to create these neutron-rich nuclei. However, producing nuclei around N = 126 and in the actinide region, which are keys to elucidate the r-process, has been challenging with these methods.

WNSC has focused on multinucleon transfer reactions. In these reactions, multiple protons and neutrons are transferred between two nuclei to form a different nucleus. WNSC was the first in the world to demonstrate that multinucleon transfer reactions between a heavy xenon ion beam and a platinum target can produce a greater number of neutron-rich nuclei around N = 126 than with conventional methods. Currently, experimental facilities and equipment specialized in nucleosynthesis using multinucleon transfer reactions are being constructed in various countries, and theoretical research in this field is also actively conducted.

Taking advantage of this excellent opportunity, we invited leading experts in the relevant and related fields from around the world, and about 70 researchers and students from Japan and abroad participated in the event, where they gave presentations full of knowledge and experience, and engaged in lively discussions. We have decided to continue holding this workshop as a series to create a collaborative environment in which we can explore new ideas, share insights, and develop practical solutions to this field. These efforts are expected to play a significant role in unraveling the mysteries of the r-process using multinucleon transfer reactions.