Direct evidence for 3p4h excitations in 15N

doi:10.1016/0370-2693(79)90646-4

Physics Letters B

Volume 84, Issue 1, 4 June 1979, Pages 51-54

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Abstract

Direct comparison of data for $^{12} C (α, p)^{15} N$ and $^{16} O (α, p)^{19} F$ allows the identification of 3p4h states in $^{15} N$ with $J = 52^{+}, 92^{+} and 132^{+}$ . Correspondence between ¹⁹F and ¹⁵N is very good, in both transfer strengths and excitation energies.

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Cited by (14)

J dependence in 12C(6→Li3He)
1994, Physics Letters B
Measured vector analyzing powers for the $^{12} C(^{6} →Li^{3} He)$ reaction are large enough (∼0.15) and sufficiently distinct to provide assignments for the total angular momentum transfer when combined with CCBA cluster transfer calculations. Measured tensor analyzing powers ^TT₂₀ are zero within statistics for this reaction. The iT₁₁ data for the 13.17 MeV state is considerably larger than that for the other states indicating a lower spin than that for 10.69 ( $92$ ⁺) and 13.00 MeV ( $112^{−})$ states. Calculations are consistent with either $72^{+}$ or $52^{−}$ for the 13.17 MeV state.
The 18O(p, α)15N reaction at 40.9 MeV
1987, Nuclear Physics, Section A
The ¹⁸O(p, α)¹⁵N reaction has been studied at a proton energy of 40.9 MeV with an overall energy resolution of about 100keV. Differential cross sections for levels with excitation energies up to about 12 MeV were measured. Finite-range DWBA calculations were performed using cluster form factors, and the deduced spectroscopic factors compared with the shell-model calculations of Millener. Numerous states show considerably greater strength than predicted by the shell model.
Location of multiparticle-multihole strength in 16N via the 3-particle transfer reaction 13C(α, p)16N at 118 MeV
1986, Nuclear Physics, Section A
Differential cross sections were measured for the ¹³C(α, p)¹⁶N reaction at E_α = 118 MeV for an excitation energy range up to 14.5 MeV. Zero-range distorted wave Born approximation (DWBA) calculations were performed using microscopic form factors. Spin-parity assignments are suggested for states at 11.21 MeV (6⁻) and 11.81 MeV (7⁻) on the basis of Bansal-French-Zamick weak coupling calculations and DWBA calculations. Arguments from ¹⁶O(e, e'), ¹⁶O(p, p') and the present experiment are given relating to the location of J^π = 4⁻, T = 1 strength in ¹⁶N.
High-spin states in the direct 12, 13C(α, p)15, 16N reactions
1983, Nuclear Physics, Section A
The ^{12, 13}C(α, p) reactions at E_α = 35 MeV are used to study high-spin states in ¹⁵N and ¹⁶N. Theoretical prescriptions are given for normalizing DWBA predictions in a semi-microscopic model and for comparing differential cross sections in the two reactions. Angular distributions are presented for many states, with DWBA analyses for those of high spin, from 10.7 to 15.4 MeV in ¹⁵N and from 0 to 11.8 MeV in ¹⁶N. The observed magnitudes are larger than predicted. In ¹⁶N, a 4⁻ state is observed at 6.17 MeV, and theoretical comparisons indicate that a member of the strong triplet of states at 7.6 MeV, resolved in this study, has also a 4⁻ spin. Strong peaks are observed at 15.42 MeV in ¹⁵N and at 11.75 MeV in ¹⁶N, but neither peak can be explained by our theoretical analysis. The DWBA angular distributions depend sensitively on the choice of the α-particle optical potential.
Evidence for 3p-2h rotational bands in 17O
1983, Physics Letters B
Comparison is made, in the weak coupling hypothesis, between the transitions to positive parity ¹⁷O states selectively excited in the ¹⁴C(⁶Li, t)¹⁷O reaction at $E(^{6} Li) = 34 MeV$ , and those from the ¹⁶O(⁶Li,t)¹⁹Ne reaction at $E(^{6} Li) = 36 MeV$ , leading to the $K^{π} = 12^{+}$ rotational band states in ¹⁹Ne. The good results show the validity of the weak coupling hypothesis and indicate the existence of two 3p-2h bands in the ¹⁷O nucleaus. The candidates for L = 0, 2, 4 members of the $T = 12$ rotational band and for L = 4 member of the $T = 32$ band are suggested. These findings are confirmed by the extracted ³He-spectroscopic strengths.
The 12C(α, n)15O and 16O(α, n)19Ne reactions at E<inf>α</inf> = 41 MeV
1981, Nuclear Physics, Section A
Spectra and neutron angular distributions have been obtained for the (α, n) reaction on ¹²C and ¹⁶O to (a) determine whether with this reaction more detailed spectroscopic information can be extracted than from heavy-ion induced ³He transfer reactions, and (b) to compare the results obtained for (α, n) with those from the (α, p) reaction on the same target nuclei. The results indicate that the same states are populated in (α, n) as in the heavy-ion induced reactions; and that the (α, n) results agree with expectations based on the (α, p) reaction at E_α = 40 MeV. The reactions can be well described as a simple direct transfer of a ³He-like cluster. The fact that the angular distributions show a J-dependence which is reproduced in the spectroscopic calculations provides a promising spectroscopic tool.

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¹: Permanent address: University of Pennsylvania, Physics Department, Philadelphia, PA 19104, USA.

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Physics Letters B

Abstract

References (14)

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Phys. Lett.

Phys. Lett.

Phys. Lett.

Nucl. Phys.

Cited by (14)

J dependence in <sup>12</sup>C(<sup>6</sup>→Li<sup>3</sup>He)

The <sup>18</sup>O(p, α)<sup>15</sup>N reaction at 40.9 MeV

Location of multiparticle-multihole strength in <sup>16</sup>N via the 3-particle transfer reaction <sup>13</sup>C(α, p)<sup>16</sup>N at 118 MeV

High-spin states in the direct <sup>12, 13</sup>C(α, p)<sup>15, 16</sup>N reactions

Evidence for 3p-2h rotational bands in <sup>17</sup>O

The <sup>12</sup>C(α, n)<sup>15</sup>O and <sup>16</sup>O(α, n)<sup>19</sup>Ne reactions at E<inf>α</inf> = 41 MeV