The differential cross sections for the reactions 9 Be(10 B, 10 B) 9 Be and 9 Be(10 B, 9 Be) 10 B have been measured at an incident energy of 100 MeV. The elastic scattering data have been used to determine the optical model parameters for the 9 Beϩ 10 B system at this energy. These parameters are then used in distorted-wave Born approximation ͑DWBA͒ calculations to predict the cross sections of the 9 Be(10 B, 9 Be) 10 B proton exchange reaction, populating the ground and low-lying states in 10 B. By normalizing the theoretical DWBA proton exchange cross sections to the experimental ones, the asymptotic normalization coefficients ͑ANC's͒, defining the normalization of the tail of the 10 B bound state wave functions in the two-particle channel 9 Beϩp, have been found. The ANC for the virtual decay 10 B(g.s.)→ 9 Beϩp will be used in an analysis of the 10 B(7 Be, 8 B) 9 Be reaction to extract the ANC's for 8 B→ 7 Beϩp. These ANC's determine the normalization of the 7 Be(p,␥) 8 B radiative capture cross section at very low energies, which is crucially important for nuclear astrophysics. ͓S0556-2813͑97͒02109-2͔
The 16 O( 3 He,d) 17 F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of 17 F. The coefficients provide the normalization for the tails of the overlap functions for 17 F→ 16 Oϩp and allow us to calculate the S factors for 16 O(p,␥) 17 F at astrophysical energies. The calculated S factors are compared to measurements and found to be in very good agreement. This provides a test of this indirect method to determine astrophysical direct capture rates using transfer reactions. In addition, our results yield S(0) for capture to the ground and first excited states in 17 F, without the uncertainty associated with extrapolation from higher energies. ͓S0556-2813͑99͒00702-5͔ PACS number͑s͒: 25.40. Lw, 25.55.Hp, 26.20.ϩf, 27.20.ϩn
13N͑p , ␥͒ 14 O is one of the key reactions which trigger the onset of the hot CNO cycle. This transition occurs when the proton capture rate on 13 N is faster, due to increasing stellar temperature ͑ജ10 8 K͒, than the 13 N -decay rate. The rate of this reaction is dominated by the resonant capture through the first excited state of 14 O ͑E r = 0.528 MeV͒. However, through constructive interference, direct capture below the resonance makes a non-negligible contribution to the reaction rate. We have determined this direct contribution by measuring the asymptotic normalization coefficient for 14 O → 13 N+ p. In our experiment, an 11.8 MeV/ nucleon 13 N radioactive beam was used to study the 14 N͑ 13 N, 14 O͒ 13 C peripheral transfer reaction, and the asymptotic normalization coefficient, ͑C p 1/2 14 O ͒ 2 = 29.0± 4.3 fm −1 , was extracted from the measured cross section. The radiative capture cross section was estimated using an R-matrix approach with the measured asymptotic normalization coefficient and the latest resonance parameters. We find the S factor for 13 N͑p , ␥͒ 14 O to be larger than previous estimates. Consequently, the transition from the cold to hot CNO cycle for novae would be controlled by the slowest proton capture reaction 14 N͑p , ␥͒ 15 O.
The 15 N(p, γ ) 16 O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong 16 O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0) = 36.0 ± 6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200 ± 300 cycles of the main CN cycle one CN catalyst is lost due to this reaction.
The14 C(n, γ) 15 C reaction plays an important role in inhomogeneous big bang models. In [N. K. Timofeyuk et al., Phys. Rev. Lett. 96, 162501 (2006)] it was shown that the 14 C(n, γ) 15 C radiative capture at astrophysically relevant energies is peripheral reaction, i.e. the overall normalization of its cross section is determined by the asymptotic normalization coefficient (ANC) for 15 C → 14 C+n. Here we present new measurements of the 14 C(d, p) 15 C differential cross sections at deuteron incident energy of 17.06 MeV and the analysis to determine the ANCs for neutron removal from the ground and first excited states of 15 C. The results are compared with the previous estimations.
The 10 B͑ 7 Be, 8 B͒ 9 Be reaction has been studied with an 84 MeV 7 Be radioactive beam. The measured cross section determines the asymptotic normalization coefficients for the virtual transitions 7 Be 1 p $ 8 B. These coefficients specify the amplitude of the tail of the 8 B wave function in the two-body channel 7 Be 1 p, and may be used to calculate the S factor for the direct capture reaction 7 Be͑p, g͒ 8 B at solar energies, S 17 ͑0͒. We find that S 17 ͑0͒ 17.8 6 2.8 eV b. [S0031-9007 (99)09160-7] PACS numbers: 25.60.Je, 25.60.Bx, 26.65. + t, 26.20. + f
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