Energy and Width Measurement of the ⁹ B First Excited State Observed by the ¹⁰ B( ³ He, α) ⁹ B(p) ⁸ Be and ¹⁰ B( ³ He, α) ⁹

Abstract

PACS. 25.50 -2H-and 3H-induced reactions and scattering. PACS. 25.60 -3He-and *He-induced reactions and scattering.

Low-lying levels ofB9

“…Our primary concerns are analogs in 9 B of the 1 / 2 + , 1/2 − , and 5 / 2 + low-lying levels of 9 Be (the 3 / 2 − ground states and the lowest 5 / 2 − excited states are well established). Recent experimental results [1][2][3][4][5][6][7] are listed in Table I. These states are all unbound, broad, and overlapping, presenting serious problems for the analysis of experimental spectra.…”

The role of 14 MeV neutrons in light element nucleosynthesis

“…This would have led to Li distraction via reactions shown in Fig.2. Fig.2: (i) 6 Li+ 2 n→ 8 Li→ 8 Be+e+ῡ followed by 8 Be →2α.…”

“…The properties of the mass-9 system, in which the 9 B partner is particle unbound, even in the ground state, have been difficult to determine; the ground state is unbound to breakup into p+ 8 Be by 186 keV. There has been a large theoretical and experimental effort directed towards predicting and observing the low-lying states of 9 B, especially the first excited ½ + state (see Table I).…”

First excited12+state in9B

“…Previous experiments have reported observation of the first excited 1 2 + state in 9 B ranging from E x = 0.73 ± 0.05 MeV and width ≈ 0.3 MeV with a three state fit to 6 Li( 6 Li,t) reaction data [16], to E x = 1.8 ± 0.2 MeV and width = 0.9 ± 0.3 MeV using the 10 B( 3 He,α) reaction [17]. Numerous values between these have been reported [1,4,[18][19][20][21][22][23][24].…”

“…The concept of mirror nuclei is well established and mirror pairs such as 7 Li- 7 Be, 13 C- 13 N, 15 N- 15 O, 17 O- 17 F, and 19 F- 19 Ne are known to have nearly identical energy level schemes [1]. The properties of the mass-9 system, in which the 9 B partner is particle unbound, even in the ground state, have been difficult to determine; the ground state is unbound to breakup into p+ 8 Be by 186 keV.…”