Examination of Astrophysical S-Factor and Non-Resonant Rates of the 64Ge(p,γ)65As Reaction
DOI:
https://doi.org/10.48048/tis.2022.5685Keywords:
Light curves, Proton capture, rp-process, Waiting point, X-ray burstAbstract
The 64Ge(p,γ)65As reaction rates strongly impact the predictions of the energy generation and isotopic abundance in the rp-process in X-ray bursts. However, the rates are ambiguous at present due to the lack of experimental cross section and the uncertainty in the non-resonant reaction rates. To provide informative data for the astrophysical rates of the 64Ge(p,γ)65As reaction, we evaluate the astrophysical S factor and direct capture rates of the 64Ge(p,γ)65As reaction using the cross sections relied on the statistical theory with various mass models. The S factors at 0 energy were found to be S(0) = 7.2×105 and 1.1×106 MeV.barn for the Finite-Range Droplet Model (FRDM) and the extended Thomas-Fermi (ETFSI) mass models, respectively. These values are about 4 orders of magnitude different from the value obtained in previous study. The empirical parameters for the non-resonant-rate approximations were also deduced for the 64Ge(p,γ)65As reaction and its photodisintegration. By considering the results in this study together with those obtained in the previous work, we confirm that a strong waiting point at the 64Ge nucleus is still a doubt because of large uncertainty of the S factor and non-resonant rates. The results in this study are useful for a better understanding of the X-ray burst properties and reaction flow at 64Ge in the rp-process.
HIGHLIGHTS
- Large discrepancy up to 4 orders of magnitude in the S factor at zero energy was found
- The strength of the waiting point at 64Ge in the rp-process is still questionable
- The astrophysical rates of the 64Ge(p,γ)65As reaction are very uncertain due to the S-factor uncertainty
- The non-resonant rates of the 64Ge(p,γ)65As reaction estimated using statistical method are not significantly impacted by the FRDM and ETFSI mass models
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JJMI Zand, MEB Visser, DK Galloway, J Chenevez, L Keek, E Kuulkers, C Sánchez-Fernánde and H Wörpel. Neutron star cooling and the rp process in thermonuclear X-ray bursts. Astron. Astrophys. 2017; 606, A130.
RH Cyburt, AM Amthor, A Heger, E Johnson, L Keek, Z Meisel, H Schatz and K Smith. Dependence of X-ray burst models on nuclear reaction rates. Astrophys. J. 2016; 830, 1-20.
JU Nabi. Nucleosynthesis and the rp-process. AIP Conf. Proc. 2012; 1498, 160-8.
C Lahiri and G Gangopadhyay. Endpoint of rp process using relativistic mean field approach and a new mass formula. Int. J. Mod. Phys. E. 2012; 21, 1250074.
VV Elomaa, GK Vorobjev, A Kankainen, L Batist, S Eliseev, T Eronen, J Hakala, A Jokinen, ID Moore, YN Novikov, H Penttilä, A Popov, S Rahaman, J Rissanen, A Saastamoinen, H Schatz, DM Seliverstov, C Weber and J Äystö. Quenching of the SnSbTe cycle in the rp process. Phys. Rev. Lett. 2009; 102, 252501.
Z Meisel, G Merz and S Medvid. Influence of nuclear reaction rate uncertainties on neutron star properties extracted from X-ray burst model - observation comparisons. Astrophys. J. 2019; 872, 1-18.
A Parikh, J Jose, F Moreno, C Iliadis and T Rauscher. Impact of uncertainties in reaction Q values on nucleosynthesis in type I X-ray bursts. Phys. Rev. C 2009; 79, 045802.
A Parikh, J Jose and G Sala. Classical novae and type I X-ray bursts: Challenges for the 21st century, AIP Adv. 2014; 4, 041022.
YH Lam, JJ He, A Parikh and H Schatz. Reaction rates of 64Ge(p,γ)65As and 65As(p,γ)66Se and the extent of nucleosynthesis in type I X-ray bursts. Astrophys. J. 2016; 818, 78.
H Schartz. The importance of nuclear masses in the astrophysical rp-process. Int. J. Mass Spectrom. 2006; 251, 293.
H Herndl, J Görres, M Wiescher and BA Brown. Proton capture reaction rates in the rp process. Phys. Rev. C. 1995; 52, 1078.
M Wang, G Audi, FG Kondev and W Huang. This person is not on ResearchGate, or hasn't claimed this research yet. The AME2016 atomic mass evaluation (II). Tables, graphs and references. Chinese Phys. C 2017; 41, 030003.
T Rauscher and RT Thielemann. Astrophysical reaction rates from statistical model calculations. At. Data Nucl. Data Tables 2000; 75, 1.
D Rochman, S Goriely, AJ Koning and H Ferroukhi. Radiative neutron capture: Hauser Feshbach vs. statistical resonances. Phys. Lett. B. 2017; 764, 109-13.
P Mohr, Gy Gyurky and Zs Fulop. Statistical model analysis of α-induced reaction cross sections of 64Zn at low energies. Phys. Rev. C. 2017; 95, 015807.
JJ He, A Parikh, BA Brown, T Rauscher, SQ Hou, YH Zhang, XH Zhou1 and HS Xu. Thermonuclear 42Ti(p, γ)43V rate in type-I x-ray bursts. Phys. Rev. C. 2014; 89, 035802.
C Iliadis. Nuclear physics of stars. Wiley-VCH, Weinheim, 2015, p. 163-77.
CA Bertulani. A potential model tool for direct capture reactions. Comp. Phys. Commun. 2003; 156, 123-41.
T Rauscher, NON-SMOKERWEB, Available at: https://nucastro.org/websmoker.html, accessed July 2021.
LP Zhang, JJ He, WD Chai, SQ Hou and LY Zhang. Reevaluation of thermonuclear reaction rate of 50Fe(p,γ)51Co. Chinese Phys. C. 2016; 40, 125101.
P Moller, WD Myers, H Sagawa and S Yoshida. New finite-range droplet mass model and equation-of-state parameters. Phys. Rev. Lett. 2012; 108, 052501.
P Moller, AJ Sierk, T Ichikawa and H Sagawa. Nuclear ground-state masses and deformations: FRDM (2012). At. Data Nucl. Data Tables 2016; 109, 1-204.
F Aymard, F Gulminelli and J Margueron. In-medium nuclear cluster energies within the extended Thomas-Fermi approach. Phys. Rev. C. 2014; 89, 065807.
JM Pearson, N Chamel, S Goriely and C Ducoin. Inner crust of neutron stars with mass-fitted Skyrme functionals. Phys. Rev. C. 2012; 85, 065803.
GG Kiss, Gy Gyurky, Z Elekes, ZS Fulop, E Somorjai, T Rauscher and M Wiescher. 70Ge (p,γ)71As and 76Ge (p,n)76As cross sections for the astrophysical p-process: Sensitivity of the optical proton potential at low energies. Phys. Rev. C. 2007; 76, 055807.
Qi Chong, RZ Du, Y Gao, JY Zhu and FR Xu. Theoretical studies of proton capture reactions in A∼25 proton-rich nuclei. Sci. China Ser. G-Phys. Mech. Astron. 2009; 52, 1464-70.
K Farouqi, KL Kratz, B Pfeiffer, T Rauscher, FK Thilemann and JW Truran. Charged-particle and neutron-capture processes in the high-entropy wind of core-collapse supernovae. Astrophys. J. 2010; 712, 1359-77.
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