Structure ofN12usingC11+

K. Perajärvi

¹

,

Changbo Fu

²

,

G. V. Rogachev

³

et al.

Abstract

The level structure of 12 N has been investigated from 2.2 to 11.0 MeV in excitation energy using a 11 C+p resonance interaction with thick targets and inverse kinematics. Excitation functions were fitted using an R-matrix approach. Sixteen levels in 12 N were included in the analysis, several of them are new. Spin-parity assignments, excitation energies and widths are proposed for these levels.

Levels inN12via theN14(Chipps1, Pain2, Greife3 et al. 2015Phys. Rev. C

“…[13] and [12], consistent with the tentative microscopic cluster model assignment [24]. However, the L = 2 transfer measured in the current work supports the assignment of 2 + over 3 − .…”

“…The ∼ 0.6 MeV width derived for the 4 − state in Ref. [13] is in much better agreement with the value from the current work; however, the 4.300 MeV excitation energy is still lower than the 4.561 MeV from this work by almost 300 keV (> 10σ). In addition, the assignment by Refs.…”

“…Similarly, Ref. [13] also observed a broad structure at E x ∼ 4.3 MeV, and an R-matrix analysis (based again on mirror arguments from 12 B) suggested the 2 − and 4 − levels to be at 3.924 and 4.300 MeV, respectively. The ∼ 0.6 MeV width derived for the 4 − state in Ref.…”

“…to appear around 3.1 MeV excitation energy in 12 N. Instead, both 11 C+p measurements [12,13] associate this 2 + state with the higher 3.558 MeV level, though the earlier experiment was unable to differentiate between 1 + and 2 + [12] and the latter placed the level about 100 keV lower than previously reported [13]. It is possible that the two levels (2 + , 3 − ) are degenerate.…”

“…Individual measurements over the years [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] have reported conflicting results, some of which also disagree with the most recent compilations [18,19] 12 N levels (Q = -22.135 MeV) has not been reported [18,19]. In this work, we have utilized the JENSA gas jet target for a measurement of the 14 N(p,t) 12 N transfer reaction.…”