Nuclear Excitations in Extreme Stellar Environments: From Microscopic Structure to Astrophysical Reaction Rates

by Prof. Nils Paar (University of Zagreb)

Tuesday 13 Oct 2026, 10:30 → 12:00 Asia/Shanghai

5#/6th-603 - Meeting Room 603 (Science Building)

Abstract:

Understanding nuclear properties and excitation modes under stellar conditions is essential for modeling astrophysical processes in extreme astrophysical environments such as core-collapse supernovae and neutron star mergers, as well as in the underlying nucleosynthesis. The focus of on-going investigations in nuclear theory is on the microscopic description of nuclear excitations and their impact on weak and electromagnetic reaction rates in hot and dense environments. Special emphasis is placed on spin–isospin modes, which play a decisive role in β-decay, and electron capture at finite temperature. In addition, low-energy transitions such as the pygmy dipole strengh have important contributions in neutron rich nuclei, in particular in photoneutron and photoabsorption reactions in stellar environments. Finitetemperature eDects have recently been investigated especially in global nuclear properties, nuclear response functions, thermal unblocking of transitions, and in (n,gamma) nuclear reaction rates. By combining self-consistent relativistic energydensity functional theory with quasiparticle random-phase approximation, these studies allow a unified description of nuclear structure and reactions relevant for stellar evolution and synthesis of chemical elements in extremely hot environments in the universe.

Biography:

Prof. Nils Paar is a full professor of physics at the University of Zagreb, Faculty of Science, Croatia. He has served as Head of the Division for Theoretical Physics, Head of the Department of Physics at the Faculty of Science, and as a member of the Senate of the University of Zagreb. He obtained his Ph.D. in theoretical nuclear physics from Technical University Munich in 2003 under the supervision of Prof. Peter Ring. Following a postdoctoral position at Technical University Darmstadt until 2006, he joined the University of Zagreb Faculty of Science, where he is currently serving as a full professor. From 2014-2015 he was a Marie Curie research fellow at Universitaet Basel, Switzerland. His research activities in exotic nuclear structure and dynamics, astrophysically relevant weak-interaction processes and neutrino-induced reactions, resulted in publication record comprising over 150 papers in international scientific journals and conference proceedings, with over 5000 citations (WoS). Over the course of his career, he has overseen and mentored a multitude of scholars, guiding them through Master's, Ph.D., and postdoctoral research programs, in addition to hosting international guests. He has actively participated in international conferences and workshops, delivering more than 80 talks, including 44 invited presentations.

Host: Prof. Yifei Niu

Alternative online link：https://meeting.tencent.com/dm/CfXcuzOd0WxL

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