The extent of nucleosynthesis in models of type I X-ray bursts (XRBs) and the associated impact on the energy released in these explosive events are sensitive to nuclear masses and reaction rates around the 64 Ge waiting point. Using the well known mass of 64 Ge, the recently measured 65 As mass, and large-scale shell model calculations, we have determined new thermonuclear rates of the 64 Ge(p,γ) 65 As and 65 As(p,γ) 66 Se reactions with reliable uncertainties. The new reaction rates differ significantly from previously published rates. Using the new data, we analyze the impact of the new rates and the remaining nuclear physics uncertainties on the 64 Ge waiting point in a number of representative one-zone XRB models. We find that in contrast to previous work, when all relevant uncertainties are considered, a strong 64 Ge rp-process waiting point cannot be ruled out. The nuclear physics uncertainties strongly affect XRB model predictions of the synthesis of 64 Zn, the synthesis of nuclei beyond A=64, the energy generation, and the burst light curve. We also identify key nuclear uncertainties that need to be addressed to determine the role of the 64 Ge waiting point in XRBs. These include the remaining uncertainty in the 65 As mass, the uncertainty of the 66 Se mass, and the remaining uncertainty in the 65 As(p,γ) 66 Se reaction rate, which mainly originates from uncertain resonance energies.

Abstract. Jinping Underground lab for Nuclear Astrophysics (JUNA) will take the advantage of the ultralow background in Jinping underground lab, high current accelerator based on an ECR source and highly sensitive detector to study directly a number of crucial reactions to the hydrostatic stellar evolution for the first time at their relevant stellar energies. In its first phase, JUNA aims at the direct measurements of 25 Mg(p,γ) 26 Al, 19 F(p,α) 16 O, 13 C(α,n) 16 O and 12 C(α,γ) 16 O. The experimental setup, which include the accelerator system with high stability and high intensity, the detector system, and the shielding material with low background, will be established during the above research. The current progress of JUNA will be given. Article available at

No abstract

The astrophysical reaction rate of the 45 V(p, γ ) 46 Cr reaction, which is relevant to 44 Ti production in corecollapse supernovae, has been revised through a consistent application of the Thomas-Ehrman level displacement formalism. The new rate agrees well with that predicted by the NON-SMOKER statistical calculation with an ETFSI mass model.