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16N (1986AJ04)(See Energy Level Diagrams for 16N) GENERAL: See also (1982AJ01) and Table 16.3 [Table of Energy Levels] (in PDF or PS) here. Model calculations: (1984BA24, 1984KA1H, 1984VA06). Complex reactions involving 16N: (1981ME13, 1981OL1C, 1983EN04, 1983FR1A, 1983MA06, 1983OL1A, 1983PL1A, 1983SA06, 1983WI1A, 1984GR08, 1984HI1A, 1984HO23, 1984KA1H, 1985BE40, 1985PO11, 1986HA1P). Reactions involving muons nad neutrinos (See also reaction 14.): (1981GM02, 1981TO16, 1983EG03, 1983JA10, 1984JA06, 1984KI09, 1984NO03, 1984SR05, 1985CH04, 1985DO04, 1985NO10, 1986GM03, 1986MC02, 1986NO04, 1986RO06). Reactions involving pions (See also reaction 15.): (1981GM03, 1981RA16, 1982DE14, 1982GI12, 1983AS01, 1983ER02, 1983ER06, 1983MO1J, 1984AS05, 1984KA31). Hypernuclei: (1982KA1D, 1983CH1T, 1983FE07, 1983SH1E, 1984AS1D, 1984CH1G, 1984ZH1B). Other topics: (1982BR08, 1985AN28). Ground state properties of 16N: (1983ANZQ, 1985AN28). For a comparison of analog states in 16N and 16O, see (1983KE06, 1983SN03).
The half-life of 16N is 7.13 ± 0.02 sec: see Table 16.3 (PDF or PS) in (1971AJ02). From the character of the beta decay [see Table 16.21 (PDF or PS)] it is concluded that 16Ng.s. has Jπ = 2-: see 16O. The β-decay of 16N*(0.12) [Jπ = 0-] to 16Og.s. has been studied. The β-decay rate λβ = 0.45 ± 0.05 sec-1 which implies gP/gA = 11 ± 2 (1983GA18); λβ = 0.48 ± 0.024 sec-1, gP/gA = 11 - 12 (1985HA22). (1985HE08) recalculate λβ = 0.489 ± 0.02 sec-1 and suggest that pion exchange currents must be included in the nucleon exchange current. See also (1982AJ01, 1982GA05) and (1983MI20). The half-life of 16N*(0.12) is 5.26 ± 0.06 μsec [see (1982AJ01)], 5.40 ± 0.05 μsec (1983MI20). See also (1984GA1A, 1985MI1A) and (1981TO16, 1983JA10, 1983RH1A, 1984HO1L, 1984JA06, 1984NO03, 1985DO04, 1985TO20, 1986MC02, 1986NO04, 1986RO06; theor.).
Gamma rays with Eγ = 120.42 ± 0.12, 298.22 ± 0.08 and 276.85 ± 0.10 keV from the ground state decays of 16N*(0.12, 0.30) and the decay of the state at 397.27 ± 0.10 keV to the first excited state have been studied. τm for 16N*(0.30, 0.40) are, respectively, 133 ± 4 and 6.60 ± 0.48 psec (1983KO01).
See (1982AJ01).
See Table 16.4 (PDF or PS) and (1982AJ01).
At Eα = 34.9 MeV the spectrum is dominated by a state at Ex = 11.75 ± 0.04 MeV: see Table 16.5 (PDF or PS). Angular distributions have been analyzed with DWBA, whose predictions depend strongly on the choice of the α-particle optical potential (1983HA32). See also (1982AJ01).
For reaction (a) see (1971AJ02). Resonances observed in reactions (b, c, d) are displayed in Table 16.5 (PDF or PS) of (1982AJ01).
Proton groups have been observed to 16N states with Ex < 12 MeV and angular distributions [with E(3He) ≤ 15 MeV] lead to the Jπ assignments shown in Table 16.6 (PDF or PS).
At Eα = 46 MeV the angular distributions of the groups to 16N*(0.30, 3.96, 5.73, 7.60) have been determined: the most strongly populated state is the (5+) state 16N*(5.73): see (1971AJ02).
Observed proton groups are displayed in Table 16.7 (PDF or PS). See also (1981OS1H).
The thermal cross section is 24 ± 8 μb: see (1981MUZQ).
The scattering amplitude (bound) a = 6.44 ± 0.03 fm, σfree = 4.59 ± 0.05 b, σspininc(bound nucleus) < 1 mb (1979KO26). The total cross section has been measured for En = 0.4 to 32 MeV: see (1977AJ02, 1981MUZQ). Observed resonances are displayed in Table 16.8 (PDF or PS). See also (1985PA11, 1985RO1J; theor.).
Levels derived from observed proton groups and γ-rays are shown in Table 16.9 (PDF or PS). Gamma transitions are shown in the inset of Fig. 2. The very strong evidence for Jπ = 2-, 0-, 3- and 1-, respectively for 16N*(0, 0.12, 0.30, 0.40) is reviewed in (1971AJ02). These states provide a probe of the residual interaction relating the 1p and 2s 1d shells: see (1984BI03) for a comparison of experiment and theory for M1 observables. See also (1983GA18) and (1985PA11; theor.).
See 16C.
Partial μ--capture rates to 16N*(0.12, 0.40) [Jπ = 0-, 1-] are consistent with the assumption of a large mesonic exchange effect in the time part of the weak axial current (1979GU06). See also (1982FR08, 1983VA1E), 15N in (1986AJ01) and the "GENERAL" section here.
The angular distribution of the π+ to the four lowest states of 16N (unresolved) has been measured at Ee = 200 MeV (1983SH41), and for Eπ+ = 30 MeV (1983JE08). See also (1982COZV, 1984BLZY).
At En = 59.6 MeV differential cross sections for the protons to the first four states of 16N (unresolved) and to 16N*(6.2, 7.8) have been analyzed by DWBA. Comparisons are made with results from the 16O(γ, n) and 15N(p, γ0) reactions in the GDR region of 16O (1982NE04, 1984BR03). See also (1983SCZR).
At Et = 23.5 MeV 16N*(0, 0.30) [Jπ = 2-,3-] are strongly populated relative to 16N*(0.12, 0.40) [Jπ = 0-,1-]: see (1982AJ01).
Angular distributions are reported at E(7Li) = 50 MeV to 16N*(0, 0.30, 6.17) [Jπ = 2-, 3-, 4-] and analyzed with microscopic DWBA calculations. 16N*(0.12, 0.40, 3.35, 3.52, 3.96, 5.52, 5.73) are also populated (1984CO20). See also (1984GA1N) [E(7Li) = 78 MeV; angular distribution to 16N*(6.2)], (1983PU01) and (1984BA53; theor.).
See Table 16.10 (PDF or PS) in (1982AJ01).
At Ep = 43 MeV, the angular distribution of the 3He nuclei corresponding to a state at Ex = 9.9 MeV fixes L = 0 and therefore Jπ = 0+ for 16N*(9.9): it is presumably the T = 2 analog of the ground state of 16C: see (1982AJ01). See also (1985BLZY).
Alpha particle groups observed in this reaction are displayed in Table 16.9 (PDF or PS). For polarization studies see (1982MA25) and 20F in (1983AJ01, 1987AJ02). τm for 16N*(0.40) = 6.5 ± 0.5 psec and |g| = 1.83 ± 0.13: see (1982AJ01).
See (1982AJ01) and 20F in (1983AJ01). |
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