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Heavy ion fusion reactions play important roles in a wide variety of stellar burning scenarios. 12C+12C, 12C+16O and 16O+16O are the principle reactions during the advance burning stages of massive star. 12C+12C also triggers the happening of superburst and Type Ia supernovae. The heavy ion fusion reactions of the neutron-rich isotopes such as 24O are the major heating source in the crust of neutron star. In this talk, I will review the challenges and the recent progress in the study of these heavy ion fusion reactions at stellar energies. The outlook for the studies of the astrophysical heavy-ion fusion reactions will also be presented.

The astrophysical p process is considered the main nucleosynthesis mechanism for the creation of the p nuclei. The accurate description of this process still suffers from large uncertainties both in the astrophysical environment and the nuclear physics input. In the latter case, nuclear reaction sensitivity studies have identified a group of reactions that have a significant contribution to the final p-nuclei abundance distribution. The cross sections of such "important" reactions need to be measured experimentally and for this reason there is a major experimental effort to provide experimental data for the relevant astrophysical energies. In the present work, we introduce a new experimental setup - the SuN detector - that was developed at the National Superconducting Cyclotron Laboratory for measurements of capture reactions of astrophysical interest.

The fusion excitation function of 32S+48Ca has been measured in a wide energy range, from above the Coulomb barrier down to cross sections in the sub-μb region. The excitation function has a smooth behavior below the barrier with a rather flat slope, and no maximum of astrophysical factor S vs. energy has been observed. However, other interesting features of the dynamics of this system can be noted. In particular, the fusion barrier distribution has an unusual shape with two peaks of similar height, lower and higher than the Akyuz-Winther barrier. Preliminary coupledchannels calculations and a comparison with nearby systems yield information on the possible influence of nucleon transfer channels with positive Q-value.

In astrophysics, the first excited 0+ state of 12C at 7.654 MeV (Hoyle state) is the most important in the triple‐α process for carbon nucleosynthesis. In explosive scenarios like supernovae, where temperatures of several 109 K are achieved, the interference of the Hoyle state with the second 0+ state located at 10.3 MeV in 12C becomes significant. The recent NACRE compilation of astrophysical reaction rates assumes a 2+ resonance at 9.1 MeV for which no experimental evidence exists. Thus, it is critical to explore in more detail the 7–10 MeV excitation energy region, especially the minimum between the two 0+ resonances for carbon nucleosynthesis. The states in 12C were populated through the β‐decay of 12B and 12N produced at the ATLAS (Argonne Tandem Linac Accelerator System) in‐flight facility. The decay of 12C into three alphas is detected in a Frisch grid twin ionization chamber, acting as a low‐threshold calorimeter. This minimizes the effects of β‐summing and allowed us to investigate the minimum ab...

Proton radioactivity of 117La, was measured with much improved statistics, but no evidence is observed for the isomeric proton decay. Prompt γ‐rays were identified in proton emitters 117La, 151Lu, and beta‐delayed proton precursor 117Ba using recoil decay tagging method by coupling the Gammasphere Ge array at the target position with the Argonne Fragment Mass Analyzer (FMA).

Single‐neutron transfer with the (d,p) reaction in inverse kinematics has been used to study the properties of the light nuclei 9Li and 7He. The results for 9Li and 7Heg.s. are compared to the predictions of ab‐initio models of nuclear structure. Different possibilities for excited states in 7He are discussed in the context of other recent experimental studies of 7He.

There are many new results in the study of the heavy‐ion fusion hindrance phenomenon at extreme sub‐barrier energies since Fusion03. Some of them have been published. Presented are some new results, including the first evidence in fusion hindrance for a system with small negative Q‐value, 28Si + 64Ni, and the impact of fusion hindrance on reactions of interest to astrophysics.

We have studied the properties of low‐lying levels in 7He using the d(6He,p)7He reaction. Recent measurements of 8He breakup and the p(8He,d)7He reaction present conflicting results on 7He first excited state A broad resonance observed in the present work at EX = 2.2−0.1+0.2 MeV is identified with the expected 1/2− spin‐orbit partner to the 7He ground state. No evidence is seen of a lower first‐excited state that was recently reported.

The direct capture contribution for 13N(p,γ)14O has been determined more precisely with the peripheral transfer reaction, 14N(13N,14O)13C at the energy of 11.8 MeV/nucleon using the ANC technique. The updated 13N(p,γ)14O reaction rate is about 2.5 times larger than the standard REACLIB rate in the temperature range 0.1 < T9 < 0.3. The transition condition from the cold to hot CNO cycles has been determined with this updated rate. The influences incurred by this update have been investigated with two one‐zone nova models.