Energy Levels of Light Nuclei A = 14 - Triangle Universities Nuclear ...

For possible resonant structure in (a) see (76AJ04). For reaction (b) see (81AJ01, 86AJ01).
See also (90HA46).
6. 11 B(α, p) 14 C Q m =0.7842
Angular distributions of p 0 have been measured at E α = 1.43 to 31.2 MeV: see (76AJ04,
81AJ01, 86AJ01). At E α = 118.1 MeV angular distributions have been studied [DWBA analysis]
to 14 C*(6.09, 6.59, 6.73, 7.01, 8.32, 9.80, 10.43[u], 10.74, 11.38[u], 11.7[u], 14.67, 14.87, 15.20, 16.43,
16.72, 17.30, 21.40 [u]). It is suggested that one of the states at 11.7 MeV has J π =4 − and the
other J π =(1, 2, 3) − , and that the state at 16.43 has J π =6 − (87AN04). At E α =48MeVan
angular distribution is reported to a state at E x =23.288 ± 0.015 MeV with Γ lab =70± 3keV.
The sharpness of the state suggests that J is large, and that perhaps it is a 7 − state (88BR26,
and J.D. Brown, private communication). A search has been made for an 8 − state up to 26 MeV
(at 20 ◦ ): the upper limit for its strength is 0.2 that for the 23.29 MeV state (J.D. Brown, private
communication). See also 15 N, (89BR1J) and(88CA26; astrophys.).
7. (a) 11 B( 6 Li, 3 He) 14 C Q m =4.8027
(b) 11 B( 7 Li, α) 14 C Q m =18.1304
Below E x =10.4 MeV, 14 C*(6.09, 6.73, 6.90 + 7.01, 7.34, 8.32, 9.78) are observed in both
reactions at E(Li) = 34 MeV (84CL08): the states observed at higher excitation energies are
displayedinTable14.5. The intensities of the 3 He and α groups in the two reactions are significantly
different. Comparison of the angular distributions in reaction (a) and in the analog reaction 11 B( 6 Li,
t) 14 N, as well as other data, leads to the assignment of analog pairs: see reaction 11 in 14 N. It
is suggested that 14 C*(11.73) and not 14 C*(11.67) is populated in the inelastic pion scattering
(84CL08). For the earlier work on reaction (b), see (76AJ04).
8. 12 C(t, p) 14 C Q m =4.6410
Observed proton groups are displayed in Table 14.6. Angular distributions have been measured
at E t =5.5 to23MeV[see(81AJ01)] and at 33 MeV (86CO1T; prelim.; to 14 C*(6.09, 6.6[u], 7.01,
8.31, 10.5[u], 14.87, 16.43). For other results see (86AJ01). See also 15 N.
9. 12 C(α, 2p) 14 C Q m = −15.1731
At E α = 65 MeV angular distributions have been measured to 14 C*(0, 6.73 ± 0.02, 8.40 ± 0.14,
10.69 ± 0.05, 11.69 ± 0.06[u], 14.84 ± 0.4). The two most strongly populated states (or groups of
states) are 14 C*(6.73, 10.69). J π =1 − and (6 + ,5 − ) are favored for 14 C*(11.69, 14.84). For the
latter 4 + is considered to be very unlikely: see (86AJ01). See also (81AJ01) for the earlier work.
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