Measurements of 7 Be scattering at 87 MeV on a melamine (C 3 N 6 H 6 ) target and of 8 B at 95 MeV on C were performed. For 7 Be the angular range was extended over previous measurements and monitoring of the intensity of the radioactive beam was improved. The measurements provide a renormalization of the absolute cross section of existing data on the proton transfer reaction 14 N( 7 Be, 8 B) 13 C and lead to improved optical-model potentials used in the incoming and outgoing channels for the distorted-wave Born approximation analysis. The results yield an updated determination of the asymptotic normalization coefficient for the virtual decay 8 B → 7 Be + p. The new value, C 2 tot ( 8 B) = 0.466 ± 0.049 fm −1 , is slightly larger than, but consistent with, the previous result. This implies an astrophysical factor, S 17 (0) = 18.0 ± 1.9 eV b, for the solar neutrino-generating reaction 7 Be(p, γ ) 8 B.

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The differential cross section for the 7 Be͑d, n͒ 8 B reaction at E c.m. 5.8 MeV has been measured using the 7 Be beam generated by the radioactive nuclear beam facility at China Institute of Atomic Energy. The 8 B ions were detected in full geometry with a two-dimensional position sensitive DE-E counter telescope. The reaction cross section was determined to be 58 6 8 mb. The angular distribution data were analyzed with the distorted-wave Born approximation calculation. The astrophysical S 17 ͑0͒ factor for the 7 Be͑ p, g͒ 8 B reaction was derived to be 27.4 6 4.4 eV b through the asymptotic normalization constant extracted from the experimental data. [S0031-9007(96)00541-8] 21.10.Pc, 25.45.Hi, 26.65.+t

The identification of the quasifree mechanism is very important in the application of the Trojan horse method (THM). We present here a new phenomenological approach for selecting quasifree events in Trojan horse experiments. This approach is based on the assumption that an intermediate break-up process exists. Under certain conditions, the break-up can be considered as quasifree and events can be selected from nonnegative real number solutions of energy and momentum conservation equations. We use experimental data of Wen Q G et al (2008 Phys. Rev. C 78 035805) to preliminarily test the validity of this approach in the THM.

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