A=12C (1985AJ01)

1. (a) ⁶Li(⁶Li, n)¹¹C Q_m = 9.450 E_b = 28.171
(b) ⁶Li(⁶Li, p)¹¹B Q_m = 12.215
(c) ⁶Li(⁶Li, d)¹⁰B Q_m = 2.985
(d) ⁶Li(⁶Li, α)⁸Be Q_m = 20.804
(e) ⁶Li(⁶Li, nα)⁷Be Q_m = 2.768
(f) ⁶Li(⁶Li, pα)⁷Li Q_m = 3.550
(g) ⁶Li(⁶Li, 2α)⁴He Q_m = 20.896
(h) ⁶Li(⁶Li, 2d)⁴He⁴He Q_m = -2.951

For the earlier work see (1980AJ01). (1983MI10) (reaction (d)) report a structure in the excitation function attributed to a state of ¹²C at 30.3 MeV. Cross sections for reaction (e) and the (⁶Li, ⁵He) reaction have been measured by (1977RU1A, 1979RU07) for E(⁶Li) = 2.3 to 15 MeV. (1983WA09) have studied the 3α and 2α + 2d reactions (reactions (g) and (h)) at E(⁶Li) = 97.5 MeV. The single-spectator pole model describes the 3α results well. The yield of the 2α + 2d reaction is lower at this energy than in the earlier work at 40 MeV: this is associated with the rise in the cross section for reaction (g). See also (1979WA13, 1981WA15, 1982LA19) and ⁸Be in (1984AJ01). See also (1981NO06, 1981NOZW) and (1983KA1G, 1983KAZF).

2. (a) ⁶Li(⁶Li, ⁶He)⁶Be Q_m = -7.795 E_b = 28.171
(b) ⁶Li(⁶Li, ⁶Li)⁶Li

Broad structures are reported in the excitation functions for reaction (b) at E(⁶Li) ≈ 13 and ≈ 26 MeV. Total reaction cross sections for the elastic scattering have been measured at E(⁶Li) = 2.0 to 5.5 MeV (1983NO08). Polarization measurements have been studied at E(pol. ⁶Li) = 20.0 MeV for the transitions to ⁶Li*(0, 2.19) (1981AV1B). See also (1980AJ01), ⁶He and ⁶Li in (1979AJ01) and (1979DO1J; theor.).

3. ⁹Be(³He, γ)¹²C Q_m = 26.2788

Observed resonances are displayed in Table 12.8 (in PDF or PS). ¹²C*(28.2) appears to be formed by s- and d-wave capture. The γ₀ and γ₂ transitions to the 0⁺ states ¹²C*(0, 7.7) are strong and show a similar energy dependence. A strong non-resonant contribution is necessary to account for the γ₁ yield. The resonance structure reported by (1974SH01) appears to confirm the role of 3p3h configurations for ¹²C excitations somewhat above the giant resonance region. The γ₃ yield is relatively unstructured. See also (1983MAZZ) and (1975AJ02).

4. (a) ⁹Be(³He, n)¹¹C Q_m = 7.558 E_b = 26.2788
(b) ⁹Be(³He, p)¹¹B Q_m = 10.3227
(c) ⁹Be(³He, 2p)¹⁰Be Q_m = -0.9061

Excitation functions for neutrons, production cross sections for ¹¹C and polarizations have been measured for E(³He) = 1.2 to 10 MeV for several neutron groups: see (1968AJ02, 1975AJ02) for a listing of the earlier references. No sharp structure is observed but there is some suggestion from angular distribution data and excitation functions at forward angles for a broad structure (Γ ≈ 350 keV) at E(³He) ≈ 2 MeV: E_x = 27.8 MeV. The total cross section for ¹¹C production shows a broad maximum, σ = 113 mb at E(³He) = 4.3 MeV. In the range E(³He) = 5.7 to 40.7 MeV it decreases monotonically (1981AN16). Excitation functions and angular distributions for protons (reaction (b)) have been measured for E(³He) = 1.0 to 10.2 MeV for a number of proton groups: see (1968AJ02, 1975AJ02) for a listing of the earlier references. No pronounced structures are reported. (1982HA06) have measured the polarization of the protons for E(³He) = 13.6 MeV. The results are in agreement with earlier measurements of the analyzing power of the ¹¹B(pol. p, ³He) reaction. The equal values for the polarization and the analyzing power are in agreement with the time-reversal invariance (1982HA06). This is confirmed by (1984TR03) [E(³He) = 14 MeV]. See also, however, (1981SL03, 1983LE17, 1983RI01, 1984PO02). Polarization measurements are also reported at E(³He) = 13.0 to 14.2 MeV (1983PO13) and E(pol. ³He) = 14 MeV (1983RO22). See also (1983HA1H). For reaction (c) see (1980CO12).

5. (a) ⁹Be(³He, d)¹⁰B Q_m = 1.0930 E_b = 26.2788
(b) ⁹Be(³He, t)⁹B Q_m = -1.087

Analyzing powers have been measured at E(pol. ³He) = 33.3 MeV for nine proton groups. The cross section for ground-state tritons (reaction (b)) inceases monotonically for E(³He) = 2.5 to 4.2 MeV and then shows a broad maximum at E(³He) ≈ 4.5 MeV: see (1980AJ01) for references.

6. ⁹Be(³He, ³He)⁹Be E_b = 26.2788

The elastic scattering function decreases monotonically for E(³He) = 4.0 to 9.0 MeV and 15.0 to 21.0 MeV. At θ_c.m. = 111° a slight rise is observed for E(³He) = 19 to 21 MeV. Polarization measurements have been reported at E(³He) = 18, 31.4 and 32.8 MeV: see (1980AJ01) for references, and (1979KA1G).

7. ⁹Be(³He, α)⁸Be Q_m = 18.9123 E_b = 26.2788

Excitation functions for the α₀ group have been reported for E(³He) = 2 to 10 MeV. Analyzing powers have been measured at E(pol. ³He) = 33.3 MeV: see (1980AJ01) for references and additional information. See also ⁸Be in (1984AJ01).

8. ⁹Be(α, n)¹²C Q_m = 5.7010

Neutron groups have been observed to ¹²C*(0, 4.4, 7.7, 9.6, (10.1), (10.8)). Angular distributions of neutron groups have been measured at many energies in the range E_α = 1.75 to 23 MeV: see (1968AJ02, 1975AJ02) for references. At E_α = 35 MeV the members of the K^π = 0⁺ band and ¹²C*(9.63) are strongly populated (1981HAZV). See also (1981HAZW) and (1980JA1G, 1982SA1M; applied).

9. ⁹Be(⁶Li, t)¹²C Q_m = 10.483

At E(⁹Be) = 26 MeV, θ_lab = 10°, ¹²C*(0, 4.4, 7.7, 9.6, 10.8, 11.8) are populated: the strongest transition is to ¹²C*(9.6) (1975VE10). See also (1981KEZY).

10. ⁹Be(⁹Be, ⁶He)¹²C Q_m = 5.103

At E(⁹Be) = 26 MeV, θ = 10°, strong transitions are observed to ¹²C*(4.4, 7.7, 9.6) (1975VE10). See also (1981BR1H; theor.).

11. ¹⁰Be(³He, n)¹²C Q_m = 19.467

At E(³He) = 13 MeV neutron groups are observed to ¹²C*(0, 4.4, 7.7, 16.1, 17.8) and to excited states at E_x = 23.53 ± 0.04 [Γ < 0.4 MeV] and 27.611 ± 0.020 MeV. The latter is formed with a 0°ree; cross section of ≈ 200 μb/sr and is taken to be the first 0⁺, T = 2 state of ¹²C (1974GO23).

12. ¹⁰B(d, γ)¹²C Q_m = 25.1858

The (d, γγ) excitation function [via the J^π = 1⁺, T = 1 state at E_x = 15.1 MeV] has been measured for E_d = 2.655 to 2.91 MeV. The non-resonant yield of 15 MeV γ-rays is due to a direct capture process or to a very broad resonance: see (1975AJ02).

13. ¹⁰B(d, n)¹¹C Q_m = 6.465 E_b = 25.1858

The thin-target excitation function in the forward direction in the range E_d = 0.3 to 4.6 MeV shows some indication of a broad resonance near E_d = 0.9 MeV. Above E_d = 2.4 MeV, the cross section increases rapidly to 210 mb/sr at 3.8 MeV, and then remains constant to 4.6 MeV. Excitation functions have also been measured for E_d = 3.2 to 9.0 MeV [see (1975AJ02)] and 7.0 to 16.0 MeV (1981AN16). (1982CE02) report thick-target yields for 4.3 MeV γ-rays for E_d = 111 to 170 keV; astrophysical S-factors were also calculated. See aslo (1983SZZY; astrophys.), (1979LE1D; applied) and ¹¹C.

14. ¹⁰B(d, p)¹¹B Q_m = 9.2297 E_b = 25.1858

Thick-target yields have been measured for E_d = 91 to 161 keV (1981CE04; also calculated astrophysical S-factor). Yields of protons have been measured for E_d = 0.14 to 12 MeV. No clear resonance structure is observed: see (1968AJ02, 1975AJ02) [see also for polarization studies]. See also ¹¹B.

15. ¹⁰B(d, d)¹⁰B E_b = 25.1858

The yield of elastically scattered deuterons has been measured for E_d = 1.0 to 2.0 MeV (there is some suggestion of resonances) and for E_d = 14.0 to 15.5 MeV. Excitation functions for the deuterons to ¹⁰B*(1.74, 2.15) [J^π; T = 0⁺; 1 and 1⁺; 0, respectively] have been measured at several angles for E_d = 4.2 to 16 MeV; they are characterized by rather broad, slowly-varying structures: see (1980AJ01) [and see for polarization measurements]. See also ¹⁰B in (1984AJ01).

16. (a) ¹⁰B(d, α)⁸Be Q_m = 17.8193 E_b = 25.1858
(b) ¹⁰B(d, 2α)⁴He Q_m = 17.9111

Excitation functions have been measured for the α₀ and α₁ groups for E_d = 0.4 to 12 MeV. Broad maxima in the α₀ yield are reported at E_d ≈ 1 (Γ ≈ 0.5), 2 and 4.5 MeV (Γ ≳ 1 MeV) as well as, possibly, at 6 MeV. Involvement of the isoscalar giant quadrupole resonance [E_x ≈ 28 MeV, Γ ≈ 4 MeV] is suggested: see (1980AJ01). For reaction (b) see ⁸Be in (1984AJ01) and (1980AJ01).

17. (a) ¹⁰B(³He, p)¹²C Q_m = 19.6923
(b) ¹⁰B(³He, pα)⁸Be Q_m = 12.3258
(c) ¹⁰B(³He, 2p)¹¹Be Q_m = 3.7361
(d) ¹⁰B(³He, pn)¹¹C Q_m = 0.972

Proton groups are displayed in Table 12.9 (in PDF or PS). Angular distributions of many of these groups have been measured for E(³He) = 1.4 to 14 MeV: see (1968AJ02) for references. Reactions (b) and (c) have been used to study the α- and the p-decay of a number of ¹²C states. For a study of the matrix element between ¹²C*(12.7, 15.1) see Table 12.10 (in PDF or PS). See also (1979SHZH, 1983CH08).

18. ¹⁰B(α, d)¹²C Q_m = 1.3391

Angular distributions have been measured at E_α = 15.1 to 25.2 MeV [see (1980AJ01)] and at 29.5 MeV (1982VA1F). See also Table 12.9 (in PDF or PS) and (1983BE1Q; theor.).

19. ¹⁰B(⁶Li, α)¹²C Q_m = 23.7105

At E(⁶Li) = 4.9 MeV angular distributions have been obtained for the α-particles to ¹²C*(0, 4.4, 7.7, 9.6). The population of ¹²C*(11.8, 12.7) is also reported, as is that of ¹²C*(15.11) [T = 1]: see (1975AJ02) for references.

20. (a) ¹⁰B(¹³C, ¹¹C)¹²C Q_m = 4.526
(b) ¹⁰B(¹⁴N, ¹²C)¹²C Q_m = 14.9134
(c) ¹⁰B(¹⁶O, ¹⁴N)¹²C Q_m = 4.4495

For reaction (a) see (1983DA20). Reaction (b) has been studied at energies to E(¹⁴N) = 93.6 MeV, involving ¹²C*(0, 4.4): see (1980AJ01). See also (1983KL1A). Reaction (c) has been investigated at E(¹⁶O) = 26 to 32.5 MeV, involving ¹⁴N_g.s. and ¹²C*(0, 4.4): see (1980AJ01). See also also (1978BE1G).

21. (a) ¹¹B(p, γ)¹²C Q_m = 15.956
(b) ¹¹B(p, α)⁸Be Q_m = 8.590 E_b = 15.956
(c) ¹¹B(p, α)⁴He⁴He Q_m = 8.681

In view of the complexity of the available information on these three reactions, we will first summarize the recent experimental results and then review the evidence for the parameters of ¹²C states observed as resonances: see Table 12.11 (in PDF or PS). See (1975AJ02, 1980AJ01) for references.

(a): In the range 4 MeV < E_p < 14.5 MeV σ(γ₀) is dominated by the giant dipole resonance at E_p = 7.2 MeV (E_x = 22.6 MeV, Γ_c.m. = 3.2 MeV), while the giant resonance in γ₁ occurs at E_p ≈ 10.3 MeV (E_x = 25.4 MeV, Γ_c.m. ≈ 6.5 MeV). Absolute cross-section measurements from E_p = 5 to 14 MeV suggest that dσ/dΩ(90°_L) = 13.1 ± 1.3 μb/sr be used as a standard at the E_p = 7.25 MeV peak of the GDR (1982CO11; also derived σ(E2) for E_p = 7 to 14 MeV).

A study of the giant dipole resonance region with polarized protons (E_p = 6 to 14 MeV) sets new limits on the configuration mixing in the γ₀ giant resonance. The analysis of γ₁ is more complicated: the asymmetry results are constant either with a single J^π = 2^- state or with interference of pairs of states such as (1^-, 3^-), (2^-, 3^-) and (1^-, 2^-). The 90° yield of γ₀, γ₁, γ₂ and γ₃ [to ¹²C*(0, 4.4, 7.7, 9.6)] has been studied by (1977SN01): the γ₂ yield shows a peak at E_p ≈ 14.3 MeV with a cross section ≈ 2.3% that of γ₀ [in γ₀ yield, E_res = 15.0 MeV (1977SN01)] and perhaps as well a low-intensity structure at E_p = 11.8 MeV. The γ₃ yield exhibits two asymmetric peaks at E_p = 12.5 and 13.8 MeV (Γ ≈ 0.7 and 2.5 MeV) and a weaker structure at ≈ 9.8 MeV (1977SN01).

(1983AN09) have measured the cross sections for γ₀ and γ₁ for E_p = 18 to 43 MeV. They report giant resonances based on various excited states of ¹²C at E_x = 22.5 and 25.5 MeV (γ₀) 25.5, 27.4 and (31) MeV (γ₁), 27.4, 31 and (37) MeV (γ₃), as well as in the γ-yield to higher states (1983AN09). At E_{pol. p} = 28.7 MeV (1980BL1B) and at E_p = 40, 60 and 80 MeV radiative capture is observed to a state, or a narrow group of states, at E_x = 19.2 ± 0.6 MeV (1979KO05). See also (1981BL1H). (1982WE08) report the yield of γ-rays (γ₁₉) to ¹²C*(18.43, 19.65, 20.68) [unresolved]. The angular distribution to one or more of these three states at E_p = 28.7 MeV is reasonably in agreement with the predictions of an E1 + E2 direct-capture model although the analyzing powers are about a factor of two larger than the measured values at back angles (1982WE08) [yield of γ₁₉ for E_p = 23 to 60 MeV; γ₀ and γ₁ yields for E_p = 8 to 60 MeV; angular distributions (γ₀, γ₁) at 14.5, 17.0 and 28.7 MeV]. At E_{pol. p} = 40 and 50 MeV analyzing powers to ¹²C*(0, 4.4, 9.6) and to many unresolved states with E_x to 35 MeV are reported by (1983NO1D).

(b): Excitation functions have been measured for E_p = 3.0 to 18 MeV [see (1980AJ01)] as well as at E_p = 4.5 to 7.5 MeV (1983BO19; σ_tot(α)), 5.4 to 7.5 MeV (1981HO13; σ(150°) for α₀) and 6 to 24 MeV (1983BU06; α₀, α₁). In the recent work resonances are observed at E_p = 5.10 and 6.08 MeV (see Tables 12.11 (in PDF or PS) and 12.12 (in PDF or PS)) (1983BO19) and some broad structures are reported by (1983BU06). See also ⁸Be in (1984AJ01).

(c): This reaction has been studied for E_p = 35.4 keV to 10.5 MeV [see (1980AJ01)] and at 20 MeV (1981LA07). The total cross section has been measured for E_p = 35.4 to 1500 keV: it shows the 163 keV resonance and a broad peak centered at about 600 keV (σ_max ≈ 0.9 b). The 163 keV resonance has σ_R = 54 ± 6 mb and Γ^R_c.m. = 5.2^+0.5_-0.3 keV E_res(c.m.) = 149.8 ± 0.2 keV [E_x = 16.1059(10)]. The astrophysical S-factor and the reaction rate < σν > have been calculated. The values of < σν > obtained in this work suggest that the ¹¹B(p, 3α) reaction may be a poorer candidate for CTR than previously thought (1979DA03). At higher energy the reaction proceeds predominantly by sequential two-body decays via ⁸Be*(0, 2.9): see ⁸Be in (1984AJ01). Contributions from ¹²C*(23.0, 23.6 and 25.4) are also reported: see (1980AJ01).

See also (1979RA20, 1980CO16, 1981HO1C, 1981NA06, 1983MAZI, 1983NO1G), (1979HA1G), (1980DO1C; astrophys.) and (1979TS02, 1980OH07, 1981HA01, 1981RA15, 1982DU1A, 1982LA03, 1982LO08, 1983CO1A, 1983GO1B, 1983KU06, 1983LO15, 1983LU1A, 1983RA31, 1984GO1M, 1984LU03; theor.).

The parameters of the observed resonances are displayed in Table 12.11 (in PDF or PS). The following summarizes the information on the low-lying resonances: for a full list of references see (1968AJ02, 1980AJ01).

E_p = 0.16 MeV [¹²C*(16.11)]. This is the J^π = 2⁺; T = 1 analog of the first excited states of ¹²B and ¹²N. The γ-decay is to ¹²C*(0, 4.4, 9.6), and also ¹²C*(12.71) [see Table 12.7 (in PDF or PS)]: the angular distribution of γ₃, together with the known α-decay of ¹²C*(9.6), fix J^π = 3^- for the latter.

E_p = 0.67 MeV [¹²C*(16.57)]. The proton width [Γ_p ≈ 150 keV] indicates s-wave protons and therefore J^π = 1^- or 2^-. This is supported by the near isotropy of the two resonant exit channels, α₁ and γ₁. The α₁ cross section indicates 2J + 1 ≥ 5: therefore J^π = 2^-, [This is consistent with the results of an αα correlation study via ⁸Be*(2.9).] The γ₁ E1 transition has |M|² ≈ 0.1 W.u., suggesting T = 1.

E_p = 1.4 MeV [¹²C*(17.23)]. (2J + 1)Γ_γ₀ ≥ 115 eV. This indicates J^π = 1^-, with T = 1 most probable. J^π = 1^- is also required to account for the interference at lower energies in α₀ and γ₀ and is consistent with the αα correlation results. Two solutions for Γ_p are possible; the larger (chosen for Table 12.11 (in PDF or PS)) is favored by elastic scattering data.

E_p = 2.0 MeV [¹²C*(17.8)]. The resonance in the yield of α₀ requires natural parity, the small α-widths suggest T = 1. For J^π = 1^- or 3^- the small γ-widths would be surprising; J^π = 2⁺ would lead to a larger anomaly than is observed. J^π is then 0⁺, T = 1. (1982HA12) [E_p = 0.82 to 2.83 MeV] report E_x = 17.80 MeV [Γ_c.m. = 96 ± 5 keV] decays via a 5.10 ± 0.03 MeV γ-ray to ¹²C*(12.71): Γ_γ = 3.7 ± 1.5 eV. The angular distribution is isotropic, as expected (1982HA12).

E_p = 2.37 MeV [¹²C*(18.13)]. Seen as a resonance in the yield of 15.1 MeV γ-rays: σ_R = 0.77 ± 0.15 μb, Γ_c.m. = 600 ± 100 keV, (2J + 1)Γ_γ ≥ 2.8 ± 0.6 eV. The results are consistent with J^π = 1⁺, T = 0, but interference with a non-resonant background excludes a definite assignment.

E_p = 2.62 MeV [¹²C*(18.38)]. The resonance for α₀ requires natural parity; the presence of a large P₄ term in the angular distribution requires J ≥ 2 and l_p ≥ 2. (1982HA12) report E_x = 18.38 MeV, Γ_c.m. ≈ 400 keV, Γ_γ (to ¹²C*(9.6)) = 5.7 ± 2.3 eV, consistent with J^π = 3^-; T = 1. The total peak cross section is 4.2 ± 1.7 μb. Transitions to ¹²C*(0, 4.4) are also observed: Γ_γ ≈ 2 x 10^-3 eV and 3.2 ± 1.0 eV, repsectively.

E_p = 2.66 MeV [¹²C*(18.39)] is not seen here: see ¹¹B(p, p).

E_p = 3.12 MeV [¹²C*(18.81)]. The angular distribution of γ₀ indicates E2 radiation, J^π = 2⁺. This assignment is supported by the angular correlation in the cascade γ₁ and by the behavior of σ(α₀); T = 1 is suggested by the small Γ_α. The yield of γ₃ (to ¹²C*(9.6)) shows a peak corresponding to E_x ≈ 18.9 - 19.0 MeV. It may be due to ¹²C*(18.8) with an energy shift due to interference (1982WR01).

The structure near E_p = 3.5 - 3.7 MeV [¹²C*(19.2, 19.4)] seems to require at least two levels. The large Γ_γ₀ requires that one be J^π = 1^-, T = 1 and interference terms in σ(α₀) require another to have even spin and even parity: J^π = 2⁺; T = 0 is favored. (1982WR01) report that they do not observe any evidence for an isospin mixed doublet near E_x = 19.5 MeV [E_p = 2.9 to 4.6 MeV (60° and 90°)]. Resonances at E_p = 4.93 and 5.11 MeV, seen in σ(γ₁) also appear in σ(α₁), but not in σ(α₀). Angular distributions suggest J^π = 2⁺ or 3^- for the latter [¹²C*(20.64)]; the strength of γ₁ and absence of γ₀ favors J^π = 3^-, T = 1.

The first seven T = 1 states in ¹²B and ¹²C have been identified by comparing reduced proton widths obtained for this reaction and reduced widths obtained from the (d, p) and (d, n) reactions: see Table 12.12 (in PDF or PS) in (1980AJ01).

22. ¹¹B(p, n)¹¹C Q_m = -2.764 E_b = 15.956

Excitation functions have been reported for E_p = 2.6 to 11.5 MeV [see (1980AJ01)], from threshold to 6.0 MeV (1980RA16; σ_t), 5.4 to 7.5 MeV (1981HO13; n₀ and n₁ from 6.4 MeV) and 10.87 to 27.50 MeV (1981AN16). At the higher energies the excitation function decreases essentially monotonically (1981AN16). At the lower energies many resonances are observed: see Table 12.12 (in PDF or PS).

Polarization measurements have been carried out at E_{pol. p} = 7.3 to 26.5 MeV [see (1980AJ01)] and at E_{pol. p} = 7.0 to 16.3 MeV (1981MU1C, 1981MU1D). See also (1979BA68), (1981NO1G; applied), (1980WA1K) and (1979PH06, 1980DO01, 1980HA35, 1982RA07; theor.).

23. (a) ¹¹B(p, p)¹¹B E_b = 15.956
(b) ¹¹B(p, 2p)¹⁰Be Q_m = -11.229
(c) ¹¹B(p, d)¹⁰B Q_m = -9.230

Anomalies and maxima observed in the excitation functions of p₀, p₁, p₂ and p₃ are displayed in Table 12.12 (in PDF or PS). Studies of the scattering have been reported at E_p = 1.8 to 47.4 MeV [see (1980AJ01) but note that some of the preliminary work has not been published] and more recently at E_p = 4.5 to 7.5 MeV (1983BO19; p₀, p₁, p₂, p₃ [and α₀: see Table 12.11 (in PDF or PS)]) and 5.4 to 7.0 MeV (1981HO13; p₀, p₁). See (1983BO19) for a review of the evidence on the states with 20.2 < E_x < 22.5 MeV. It is reported that in all the channels and throughout this energy range a strong 2⁺ background is observed. It is suggested that it may be the low-energy tail of the isoscalar giant quadrupole resonance (1983BO19). For polarization measurements [E_p = 1.9 to 155 MeV] see (1975AJ02, 1980AJ01).

At E_{pol. p} = 11.34 to 11.94 MeV the VAP angular distributions and excitation functions of the deuterons (reaction (b)) have been studied by (1982BU03): a comparison with ¹⁰B(d, pol. p) shows very good agreement between the polarization and the analyzing power (1982BU03). For reaction (c) see (1979AJ01). See also (1980DO01, 1980HA35, 1983RA05; theor.).

24. ¹¹B(p, ³He)⁹Be Q_m = -10.3227 E_b = 15.956

For studies of a possible violation of time-reversal invariance see (1981SL03, 1983RI01). See, however, reactions 4 and 23 here and reaction 13 in ¹¹B. See also (1981VI1B, 1983HA1H).

25. (a) ¹¹B(d, n)¹²C Q_m = 13.732
(b) ¹¹B(d, np)¹¹B Q_m = -2.22458
(c) ¹¹B(d, nα)⁸Be Q_m = 6.365

Reported neutron groups are displayed in Table 12.13 (in PDF or PS). Angular distributions have been studied in the range 0.5 < E_d < 11.8 MeV: [see (1968AJ02, 1975AJ02)] and at E_d = 12 MeV (1983NE11). See (1983NE11), reaction 30 and Table 12.14 (in PDF or PS) in (1980AJ01) for spectroscopic factors. Angular correlation studies have been carried out at many energies in the range 0.7 < E_d < 6.3 MeV. For reactions (b) and (c) see footnotes to Table 12.13 (in PDF or PS) here as well as reaction 30 in (1980AJ01). See also (1981AN16, 1983FOZW), (1984TA1N) and ¹³C in (1986AJ01).

26. (a) ¹¹B(³He, d)¹²C Q_m = 10.463
(b) ¹¹B(³He, np)¹²C Q_m = 8.238

Observed deuteron groups are displayed in Table 12.13 (in PDF or PS). Angular distributions have been studied at E(³He) = 5.1 to 44 MeV: see (1975AJ02, 1980AJ01). At E(³He) = 43.6 MeV the regions with E_x ≈ 18.4 and ≈ 19.5 are strongly populated (1979SHZH, 1980SH1A).

27. (a) ¹¹B(α, t)¹²C Q_m = -3.858
(b) ¹¹B(⁷Li, ⁶He)¹²C Q_m = 5.982

Angular distributions (reaction (a)) have been studied at several energies in the range E_α = 15.1 to 120 MeV [see (1980AJ01)] as well as at E_α = 29.5 MeV (1982VA1F; t₀, t₁). See also (1979ZE1B, 1980ZE05, 1982BE17, 1983BE1Q, 1984ZE1B; theor.). At E(⁷Li) = 34 MeV, angular distributions have been measured for the groups to ¹²C*(0, 4.4, 7.7, 9.6, 10.8, 11.8, 12.7, 15.1, 16.1, 18.35) (1983NE11). It is concluded on the basis of this and other work, that the group corresponding to E_x = 18.35 ± 0.05 MeV (Γ = 350 ± 50 keV) consists of unresolved states with J^π = 3^- (T = 1) and 2^- (T = 0 + some mixing of T = 1) (1983NE11; see for spectroscopic factors): no states were observed with E_x > 18.35 MeV.

28. (a) ¹¹B(¹⁴N, ¹³C)¹²C Q_m = 8.406
(b) ¹¹B(¹⁶O, ¹⁵N)¹²C Q_m = 3.829

Angular distributions (reaction (b)) have been measured at E(¹⁶O) = 27 to 60 MeV, involving ¹²C*(0, 4.4, 9.6): see (1980AJ01). See also (1979ZE1B, 1983EL01; theor.). For reaction (a) see (1980AJ01) and (1978DZ1A; theor.).

29. ¹²B(β^-)¹²C Q_m = 13.369

The decay is mainly to ¹²C_g.s.; branching ratios to ¹²C*(0, 4.4, 7.7, 10.3) are displayed in Table 12.14 (in PDF or PS). All the observed transitions are allowed. The half-life is 20.20 ± 0.02 msec (1978AL01).

¹²C*(7.7) [J^π = 0⁺] is of particular interest for helium burning processes in stars: Γ_rad = 3.41 ± 1.12 meV. A search for transitions to ¹²C*(12.7) has been unsuccessful: see (1968AJ02, 1975AJ02). The shapes of the β-spectra of ¹²B and ¹²N have been analyzed. The results are in agreement with CVC and with the absence of second-class induced tensor currents. See also reaction 63, (1981KA31, 1982PRZZ), (1980AJ01) and (1980OK01, 1981KO27, 1984BO03; theor.).

30. (a) ¹²C(γ, n)¹¹C Q_m = -18.721
(b) ¹²C(γ, 2n)¹⁰C Q_m = -31.8415

The total absorption, mainly (γ, n) + (γ, p), is dominated by the giant resonance peak at 23.2 MeV, Γ = 3.2 MeV [σ_max = 21 mb (1975AH06)] and by a smaller structure at 25.6 MeV, Γ ≈ 2 MeV [σ_max ≈ 13 mb (1975AH06)]: see (1968AJ02, 1975AJ02) for a detailed listing of the earlier references and results.

The (γ, n) cross section shows a giant resonance centered at about 22.5 MeV, Γ ≈ 3 MeV (σ_max ≈ 8 mb), a secondary maximum at 25.5 MeV, Γ ≈ 2 MeV, and a long tail: see (1980AJ01). The (γ, n₀) cross section has been measured at 90° for 21 < E_x < 40 MeV and compared with the (γ, p₀) cross section: the isospin mixing averages about 2% in intensity and shows structure at the giant resonance. Angular distributions of n₀ measured over the giant-resonance region indicate that the main excitation mechanism is of a 1p_3/2 → 1d_5/2 E1 single-particle character. No significant E2 strength is observed: see (1980AJ01) and (1980GO13; E_γ = 60 MeV).

The cross section for reaction (b) has been measured for E_γ = 35 to 130 MeV. The (γ, 2n) cross section is very much smaller than that for (γ, n): the highest value is 0.15% of the maximum value for reaction (a) in the energy range E_γ = 20 to 140 MeV. Reaction (b) has been studied for E_bs = 100 to 800 MeV: see (1980AJ01). For work at high energies see (1979DU1C, 1980GA29). See also (1980AR1G), (1980SC1G), (1982VI07; applied) and (1980DU21, 1980TA1D, 1981BE2M, 1981DE18, 1981KO1G, 1981RO1N, 1982CA01, 1982LO08, 1983BE1U, 1983BE45, 1983BO1G, 1983BO1B, 1983CA22, 1983GI02, 1984CO07, 1984KO33; theor.).

31. (a) ¹²C(γ, p)¹¹B Q_m = -15.956
(b) ¹²C(γ, π⁰⁾¹²C Q_m = -134.963
(c) ¹²C(γ, π⁺)¹²B Q_m = -152.937
(d) ¹²C(γ, π^-)¹²N Q_m = -156.905

The photoproduction cross section exhibits two broad peaks, the giant resonance peak at 22.5 MeV, Γ = 3.2 MeV, σ_max = 13.1 ± 0.8 mb and a 2 MeV broad peak at 25.2 MeV, σ_max = 5.6 ± 0.3 mb: see (1976CA21) and Table 12.19 (in PDF or PS) in (1968AJ02). For a recent study of the absolute (γ, p₀) cross section at 90° see (1984KE05). While the E1 component dominates in the GDR, a 2% E2 contribution may possibly be present (1976CA21). In contrast with the giant resonance peak in the (γ, n) cross section, the (γ, p) cross section shows a strong peak in the center of the broad giant-resonance peak. Above 24.5 MeV the ground state (γ, p) and (γ, n) excitation functions have the same shape up to at least 36 MeV (E.G. Fuller, private communication). There is agreement between the (γ, p) results and those from the inverse reaction ¹¹B(p, γ₀)¹²C [see reaction 21] when the population of ¹¹B*(4.4, 5.0) is taken into account. [See also (1984KE05)]. The fraction of transitions to ¹¹B*(0, 2.1, 4.7) have been determined at energies in the range E_bs = 21.7 to 42 MeV: most of the transitions are to ¹¹B_g.s. and the excited-state transitions appear to orginate from localized E_x regions (1970ME17, 1980IS1F). For (γ, pX) momentum spectra using tagged photons, see (1983HO01; E_γ = 357 to 557 MeV) and (1984BA09; E_γ = 360 to 600 MeV). See also (1982BA32, 1983DO09), ¹¹B and (1980AJ01).

The photoproduction of neutral pions (reaction (b)) has been studied at E_bs = 145 MeV (1982DO12) and from threshold to 450 MeV (1983AR08; total σ). See also (1978EP03, 1981ROZZ, 1982COZY, 1983TI1B). (1980AR16) have obtained the total inclusive cross section and the total (γ, p) cross section [with, and without, a pion in the final state] for E_γ = 210 to 381 MeV. (1982AR06) have studied the production of charged pions for the same energy range. (1978AR08) have measured the cross section for π^- production in the range 510 to 750 MeV. See also (1979EP02, 1979GL05, 1980AN1H, 1981AL1E, 1981MC02, 1983SH1W), (1980AJ01) and ¹²B and ¹²N.

32. (a) ¹²C(γ, d)¹⁰B Q_m = -25.1858
(b) ¹²C(γ, pn)¹⁰B Q_m = -27.4104
(c) ¹²C(γ, t)⁹B Q_m = -27.366

Cross sections and angular distributions of the deuterons corresponding to transitions to ¹⁰B_g.s. and/or low excited states have been measured at E_γ ≈ 40 MeV: the results are consistent with E2. There is some evidence also for the excitation of higher states of ¹⁰B via non-E2 transitions. For E_bs = 90 MeV, the ratio of the yields of deuterons to protons is ≈ 2%, for particle energies 15 to 30 MeV. For higher particle energies, the ratio decreases: see (1980AJ01) for references. See also (1981AL1E). For reaction (b) see (1975AJ02), (1980KH08, 1981DO1D, 1981KH08, 1982DO08) and (1984CH1A; theor.). The yield of tritons has been measured for E_γ = 35 to 50 MeV: see (1980AJ01).

33. (a) ¹²C(γ, α)⁸Be Q_m = -7.3665
(b) ¹²C(γ, pα)⁷Li Q_m = -24.6206
(c) ¹²C(γ, nα)⁷Be Q_m = -26.2649
(d) ¹²C(γ, pnα)⁶Li Q_m = -31.8707

The cross section for reaction (a) exhibits broad peaks at about 18 MeV and ≈ 29 MeV; a pronounced minimum occurs at 20.5 MeV: to what extent the peaks have fine structure is not clear. For E_γ < 22 MeV, transitions are mainly to ⁸Be_g.s. and ⁸Be*(2.9) with the g.s. transition dominating for E_γ ≲ 14 MeV. For E_γ > 26.4 MeV, ⁸Be (T = 1) levels near 17 MeV are strongly excited. Alpha energy distributions show surprisingly strong E1 contributions below E_γ ≈ 17 MeV: see (1980AJ01) for references. See also (1983LIZN), (1981CH28), (1982SA1A; astrophys.) and (1979KA21, 1982DU1A; theor.).

The yield of 0.48 MeV γ-rays from the decay of ⁷Be, formed in reaction (c), shows a resonance at E_γ ≈ 29.5 MeV, σ = 0.9 ± 0.2 mb: see (1975AJ02). For reactions (b) and (c) see (1979KI04, 1980KI1E). For reaction (d) see (1982DO1G, 1982DO14).

34. ¹²C(γ, γ)¹²C

Resonance scattering and absorption by ¹²C*(15.11) have been studied by many groups: see (1980AJ01) and Table 12.7 (in PDF or PS) here. Inelastic scattering has also been reported to ¹²C*(4.4, 9.6 ± 0.2, 11.8 ± 0.2, 12.7, 13.3 ± 0.2, 17.2 ± 0.2, 18.3 ± 0.2, 20.5 ± 0.2, 22 - 24 (giant resonance), 26.5 ± 0.4, 29.5 ± 0.3): see (1980AJ01) and (1980IS09, 1980IS13, 1982NOZV). See also (1982PIZW). Measurements of the cross section at 90° and 135° for E_γ = 23.5 to 39 MeV indicate a significant E2 strength [1.9^+0.8_-0.7 total isoscalar + isovector energy weighted sum rule], in addition to the dominant E1 strength (1980DO04, 1983DO05). However, the data of (1984WR01; E_γ = 20 to 50 MeV) are inconsistent with these results: there is no "compact" E2 strength in that energy interval. The data taken at 23.5 MeV, the peak of the giant resonance, were combined to determine the total photonuclear absorption cross section at that energy, 19.7 ± 0.4 mb. Γ_4.4/Γ₀ at 23.5 MeV = 0.23 ± 0.07 (1983DO05). The scattering cross section has been measured for E_γ = 150 to 400 MeV by (1984HA08). For pair-production measurements at E_bs = 4.2 to 31.1 MeV see (1983NO06). See also (1980HA1W) and (1981KE16, 1981KO1F; theor.).

35. ¹²C(e, e)¹²C

The nuclear charge radius is < r² >^1/2 = 2.472 ± 0.015 fm (1980CA07), 2.464 ± 0.012 fm [2.468 ± 0.012 when the dispersion correction is made] (1982RE12). A value obtained from muonic X-rays is displayed in the "GENERAL" section here. See also (1979BA72). For earlier results see (1980AJ01). Elastic scattering has been studied up to 4 GeV [see (1968AJ02, 1975AJ02)] and at 25 to 115 MeV (1980CA07) and 100 to 300 MeV (1982RE12).

¹²C states observed in inelastic scattering are displayed in Table 12.15 (in PDF or PS). The variation of the form factor with momentum transfer yields unambiguous assignments of J^π = 2⁺, 0⁺ and 3^- for ¹²C*(4.4, 7.7, 9.6). Longitudinal form factors show ¹²C*(16.1, 18.6, 20.0, 21.6, 22.0, 23.8, 25.5) while the transverse form factors show ¹²C*(15.1, 16.1, 16.6, 18.1, 19.3, 19.6, 20.6, 22.7, (25.5)). ¹²C*(19.3) may be the expected giant magnetic quadrupole state, J^π = 2^-: see (1975AJ02, 1980AJ01) for references and additional information. At E_e = 150.6 MeV (θ = 180°) two peaks are observed at 16.1 and at 19.6 MeV corresponding to E2 and M2 - M4 excitations (1984RY01). There are no further peaks at higher E_x (1984RY01) in contradiction to the predictions of (1983CA17). Deep-inelastic scattering up to and including the Δ-region has been studied by (1983BA28, 1983BA54). For an attempt to observe axions see (1979BE1U) and reaction 40.

36. (a) ¹²C(e, ep)¹¹B Q_m = -15.9561
(b) ¹²C(e, en)¹¹C Q_m = -18.721
(c) ¹²C(e, eπ⁺)¹²B Q_m = -152.937
(d) ¹²C(e, eπ^-)¹²N Q_m = -156.905

Electron spectra in the region of large energy loss show a broad peak which is ascribed to quasi-elastic processes involving ejection of single nucleons from bound shells: see (1968AJ02). Studies of e' - p coincidences for E_e = 497 to 700 MeV reveal peaks corresponding to ejection of 1p and 1s protons: the energy of the two peaks [Γ = 6.9 ± 0.1 and 19.8 ± 0.5 MeV] are 15.5 ± 0.1 and 36.9 ± 0.3 MeV (1976NA17: 700 MeV; DWIA). By studying the missing energy spectrum at E_e = 497 MeV the population of ¹¹B*(0, 2.14, 5.0) is reported: see (1980AJ01) for references. At E_e = 500 MeV momentum distributions for the transition to ¹¹B_g.s. have been studied by (1982BE02): measurements have been made for both perpendicular and parallel kinematics with -150 MeV/c ≤ p ≤ 150 MeV/c. (1980CA1L; prelim) have extracted the yield for the proton decay of the giant resonance to various states of ¹¹B for E_e = 86 and 126 MeV (see ¹¹B): the results indicate that more than one J^π = 1^- doorway state is important in the ¹²C giant resonance.

The π^-/π⁺ ratios have been measured at E_π = 10 MeV (1979JE04), 15.8 and 17.9 MeV (1982LO07; E_e = 200 MeV). Pion production has also been studied by (1981SE05, 1983SC11): see ¹²B and ¹²N. See also (1980AJ01) and the "GENERAL" section here.

37. (a) ¹²C(π^±, π^±)¹²C
(b) ¹²C(π^±, π^±p)¹¹B Q_m = -15.9561
(c) ¹²C(π^±, π^±n)¹¹C Q_m = -18.721
(d) ¹²C(π⁺, p)¹¹C Q_m = 121.629
(e) ¹²C(π^-, p)¹¹Be Q_m = 112.103

Angular distributions of the elastic and inelastically scattered pions have been measured at many energies: see Table 12.16 (in PDF or PS). (1980BA45) have compared the elastic cross sections of π⁺ on ¹²C and on ¹¹B at E_π⁺ = 38.6 and 47.7 MeV. The difference in the charge radius < r² >^1/2 is 0.072 ± 0.021 fm for ¹²C and ¹¹B. See also (1984DU01; theor.).

At E_π⁺ = 162 MeV π⁺ - γ angular correlations via ¹²C*(4.4) have been studied by (1984VO04): the results support use of the isobar-hole formalism. At E_π^± = 100 to 130 MeV the charge-dependent matrix element between ¹²C*(12.71, 15.11) has been studied by (1981MO07): see Table 12.10 (in PDF or PS). ¹²C*(14.1, (15.4), 16.1) are also populated. The possible group to ¹²C*(15.4) has a width of ≈ 2 MeV (1981MO07). A strong energy-dependent enhancement in the pion scattering to ¹²C*(15.1) but not to ¹²C*(12.7) is observed at E_π^± = 100, 180 and 230 MeV: this is interpreted as possible evidence for direct (Δ - h) components in the wave function of the T = 1 state (1982MO01). Multiple scattering is a very important feature in the quasielastic region (1980BU07; E_π^± = 180 and 291 MeV). However (1983LE12) have studied inclusive pion scattering at E_π⁺ = 100, 160, 220 and 300 MeV: a peak is observed near that expected from single-step quasifree scattering. The ratio of π⁺/π^- inelastic yields has been measured at E_π^± = 100, 160 and 220 MeV (1981MC09). The cross section for absorption of pions in ¹²C has been obtained at E_π^± = 50, 85 to 315 MeV and E_π^- = 125 and 165 MeV. A strong energy dependence is observed in the π⁺ absorption (1981AS07, 1983NA18). At E_π^± = 50 MeV the absorption of π^- is about twice that of π⁺ (1983NA18).

(1981PI05, 1982PI03, 1982PI04) have studied reaction (b) at E_π⁺ = 165 MeV and E_π^± = 245 MeV. See also (1979FR1K, 1983LIZS). For reaction (c) see (1979FR1K, 1981PI05, 1982PI04). For reactions (d) and (e) see (1981MC09). See also (1980AJ01) for additional studies, as well as (1979DA16), (1980DE1V, 1983TR1J) and (1980NA06, 1980PE01, 1981TO17, 1982OS01, 1983AM03, 1983BA62, 1983RA31; theor.) and the "GENERAL" section here.

38. ¹²C(K^±, K^±)¹²C

At E_K^± = 442 MeV angular distributions have been obtained for ¹²C*(0, 4.4, 9.6) (1982MA16). See also (1979CH34).

39. (a) ¹²C(n, n)¹²C
(b) ¹²C(n, nα)⁸Be Q_m = -7.3665

Angular distributions of elastic and inelastically scattered neutrons have been studied at many energies up to 350 MeV: see (1980AJ01) and (1983WO02; n₀; 8.9 → 14.9 MeV), (1983DA22; n₀; 9.6 → 15 MeV), (1983ANZY; n₀, n₁; 10 MeV; small angles), (1982HAZK; n₀; 14.6 MeV), (1981GU12; n₀, n₁, n₂, n₃; 14.7 MeV), (1980TH07; n₀, n₁; 15.0 → 18.25 MeV), (1979BE50; n₀; 16.1 MeV), (1981MEZV, 1982MEZZ, 1983MEZY, 1983MEZS, 1983PEZY; neutrons to ¹²C*(0, 4.4, 7.7, 9.6, 10.8, 11.8, 12.7, 13.4, 14.1, 15.1, 16.1); E_n = 20.7 to 26 MeV) and (1979DEZK; n₀; 30.3, 40 MeV). Angular correlations (n₁, γ_4.4) have been studied at E_n = 13.9 to 15 MeV: see (1975AJ02). For discussions of the spin-flip probability involving the transition to ¹²C*(4.4), see (1975AJ02) and (1980TH07). The quadrupole deformation parameter β₂ = -0.67 ± 0.04 (1983WO02). For polarization studies see (1980TH07, 1983WO02) and (1986AJ01).

For a kinematically complete study of reaction (b) at E_n = 11 to 35 MeV see (1983AN02): the sequential decay via ¹²C*(9.64) and ⁸Be_g.s. is clearly observed at the higher energies. For the earlier work see (1980AJ01). See also (1979SM08, 1982KN02, 1983SH2K), (1979SO1B, 1980JA1G; applied) and (1980AK01, 1980SH01, 1982FI1L, 1982OL1C, 1983BA1T, 1983GU1F; theor.).

40. ¹²C(p, p)¹²C

Angular distributions of elastically and inelastically scattered protons have been measured at many energies up to E_p = 1040 MeV: see Tables 12.22 (in PDF or PS) in (1968AJ02), 12.20 (in PDF or PS) in (1975AJ02), 12.17 (in PDF or PS) in (1980AJ01) and 12.17 (in PDF or PS) here.

Table 12.18 (in PDF or PS) displays the information on excited states of ¹²C. A summary of the decay of some excited states is shown in Table 12.7 (in PDF or PS). The angular distributions have been analyzed by DWBA (and CCBA), DWIA (including microscopic calculations) and DWTA (DW t-matrix approximation with density-dependent interactions). Microscopic DWIA calculations give good results for transitions which take place through the S = T = 1 part of the effective interaction and also gives a reasonable description of the S = T = 0 transition. However the mechanism for the excitation of ¹²C*(12.71) (S = 1, T = 0) remains a puzzle (1980CO05; E_p = 122 MeV). The angular distributions of the inelastically scattered protons to ¹²C*(12.71) are usually poorly fitted: see e.g. (1983BA57).

At E_p = 402 MeV the differential cross sections for ¹²C*(12.7, 15.1) (J^π = 1⁺) are very similar for large q. This may be due to the smallness of precursor effects [precursor to a pion condensate] (1981ES04). See also (1981SU04; theor.).

The spin-flip probability (SFP) for the transition to ¹²C*(4.4) has been measured for E_p = 15.9 to 41.1 MeV: two bumps appear at ≈ 20 and ≈ 29 MeV. It is suggested that the lower one is due to a substructure of the E1 giant dipole resonance while the upper one results from the E2 giant quadrupole resonance (1975DE32, 1982DE02). The SFP has also been studied at E_{pol. p} = 24.1, 26.2, 28.7 MeV (1981FU12; to ¹²C*(4.4)), at E_p = 42 MeV (1981CO08; to ¹²C*(12.7)), at E_{pol. p} = 397 MeV (1982SE12; to ¹²C*(9.6, 12.7, 15.1, 16.1)) [the SFP to ¹²C*(9.6) is consistent with zero; the others exhibit large SFP at forward angles] and at E_p = 398, 597 and 698 MeV (1983JO08; to ¹²C*(18.3, 19.4)). At E_{pol. p} = 23 to 27 MeV (1980HO06) have tried to study out-of-plane (p, p'γ) angular correlations to determine the SF M1 contribution to the cross section for ¹²C*(12.7, 15.1): the study was not successful. See also (1979PR04).

(1980HO07) have measured the angular distribution of γ-rays from the decay of ¹²C*(12.7, 15.1) at E_p = 21.5 to 27 MeV. Microscopic DW calculations were performed for the A₀ and a₂ coefficients from these and earlier data. The theoretical calculations underestimate A₀ for energies below 35 MeV and are in agreement with the experimental A₀ for higher energies. The calculations also predict significant differences in the a₂ values for the transitions from ¹²C*(12.7, 15.1), and these are observed (1980HO07). β₂ = -0.663, β₄ ≈ 0 for ¹²C_g.s. (1983DE36).

For polarization studies see (1979GA13, 1980KA02, 1980MO06, 1981CO10, 1981CO20, 1981CO21, 1981FU12, 1981ME02, 1982CA08, 1982CO21, 1982SE12, 1983FU1J, 1983HO1L, 1983HU06, 1983JO1J, 1983JO08, 1983MC02, 1983ME02, 1983TA12, 1984BAZZ, 1984KOZZ, 1984MC01, 1984MC04) and ¹³N in (1981AJ01, 1986AJ01).

A study of inclusive reactions in the region dominated by the Δ-isobar (E_x ≈ 300 MeV) is reported by (1984MC04: E_p = 800 MeV). See also (1984SEZZ). For spallation see (1979KO21; E_p = 640 MeV) and (1983AN13; E_p = 1.05 and 2.1 GeV). See also (1980CH05). For π^- production see (1983MO14). (1979CA1F) have studied the decay of ¹²C*(12.7, 15.1) looking for axions (m ≈ 12 MeV): the results were negative. The e⁺e^- pair decay of ¹²C*(15.1) has been observed (1982EN01; E_p = 22 MeV).

41. ¹²C(p-bar, p-bar')¹²C

Antiproton scattering angular distributions have been measured at an antiproton energy of 46.8 MeV to ¹²C*(0, 4.4) and compared with proton scattering work at about the same energy. Limits have been deduced for the strengths of the real and imaginary parts of the antiproton-carbon optical potential. There is some evidence for the excitation of ¹²C*(9.6, 15.1). The continuum cross section is smaller than for the corresponding proton data (1984GA04). Differential cross sections for the elastic scattering of antiprotons with momenta in the range 470 to 880 MeV/c have been measured by (1984NA03). See also (1984PEZY) and (1984KA14, 1984LO04, 1984SAZT; theor.).

42. (a) ¹²C(p, 2p)¹¹B Q_m = -15.9561
(b) ¹²C(p, pn)¹¹C Q_m = -18.721
(c) ¹²C(p, pd)¹⁰B Q_m = -25.1858
(d) ¹²C(p, pα)⁸Be Q_m = -7.3665
(e) ¹²C(p, 3p)¹⁰Be Q_m = -27.1849

The (p, 2p) reaction has been studied at energies up to 1 GeV: see (1975AJ02) for the earlier work, and ¹¹B here. See also (1979DE35, 1980TAZI). Although the shapes of the momentum distributions in the (p, pn) reaction (reaction (b)) at 400 MeV are consistent with quasifree knockout from distinct shells, the magnitude of the cross section relative to that for the (p, 2p) process is inconsistent with the PWIA model (1979JA20). See aslo (1982REZZ).

At E_p = 670 MeV the missing energy spectrum in the (p, pd) reaction (reaction (c)) shows a strong bump at E_miss. = 25 MeV and another weaker one at E_miss. = 45 MeV corresponding, respectively, to the ¹⁰B ground-state region and ¹⁰B*(20) (1981ER10).

At E_p = 56.5 MeV reaction (d) proceeds primarily by sequential α-decay. ¹²C*(22.2 ± 0.5, 26.3 ± 0.5) which subsequently decay to ⁸Be_g.s. must therefore have natural parity and a significant T = 0 admixture. ¹²C*(19.7, 21.1, 26.3) decay to ⁸Be*(2.9). These states must also have a T = 0 component. It is suggested that ¹²C*(21.1) has unnatural parity (1969EP01). In recent work at E_p = 44.2 MeV ¹²C*(12.7, 14.1, 21.6, 26.6) are observed in the angular correlation involving α₀ and ¹²C*(21.6, 24.1, 26.6) decay via α₁ to ⁸Be*(2.9) [suggesting 2⁺ for these states, assuming that only resolved states are involved (1981DE08)].

For reaction (e) see (1979KO36, 1979NA14, 1980KO40, 1981KO1H). For backward scattering at 400 GeV see (1979BA28). For other reactions see reaction 49 in (1980AJ01). See also (1981TA1E, 1983AN18, 1983BEYW), (1979RA1C; astrophys.), (1980AJ01, 1983CH1B) and (1978UC1A, 1979AB13, 1979KI10, 1979KN03, 1979MA24, 1979MA1M, 1980BA2E, 1980SM03, 1981AM01, 1981IL1A, 1981IS11, 1981SA37, 1981ZH1E, 1981ZH1F, 1982CH1P, 1982JA02, 1982KA1L, 1982KI1G, 1982ZH02, 1982ZH06, 1983IK03, 1983IS1C, 1983LI18, 1983LU1C, 1983TA1H, 1983VD1B; theor.).

43. (a) ¹²C(d, d)¹²C
(b) ¹²C(d, pn)¹²C Q_m = -2.2246
(c) ¹²C(d, dα)⁸Be Q_m = -7.3665

The angular distribution of elastically and inelastically scattered deuterons has been studied at many energies: see (1968AJ02), Tables 12.22 (in PDF or PS) in (1975AJ02), 12.17 (in PDF or PS) in (1980AJ01) and 12.17 (in PDF or PS) here. In addition to well-known states in ¹²C such as ¹²C*(4.4) [E_x = 4440.5 ± 1.1 keV] and ¹²C*(12.7, 15.1) [see Table 12.10 (in PDF or PS) for charge-dependent matrix element], the population of ¹²C*((10.8 ± 0.2), (11.8 ± 0.2), 18.3 ± 0.3, 20.6 ± 0.3, 21.9 ± 0.3 (broad), ≈ 27 (broad)) is also reported. See (1980AJ01) for references and for additional structures which have not been published. Calculated deformation parameters listed in (1980AJ01) are β₂ = -0.48 ± 0.02 and 0.47 ± 0.05, and β₃ = 0.35 ± 0.06.

Reaction (b) has been studied at E_d = 5.0 to 9.85 MeV [see (1980AJ01)] and at 56 MeV (1983BA37). See also (1983WI1D). For spallation studies see (1983AN13; 2.1 and 4.2 GeV). For reaction (c) see (1979HE06). For π^- production see (1983MO14). See also ¹⁴N in (1981AJ01, 1986AJ01), (1976ZA1B, 1983AB1E, 1983JI04, 1984GR1F), (1979DE1P, 1981DA1B) and (1977MA44, 1980LE14, 1982EV1A, 1982NI1B, 1982TA19, 1983GA14, 1983MA1U, 1984EV1C, 1984KH01; theor.).

44. ¹²C(t, t)¹²C

Angular distributions of elastically scattered tritons have been determined at E_t = 1.0 to 20.04 MeV: see (1975AJ02) and Table 12.17 (in PDF or PS) here. See also ¹⁵N in (1981AJ01) and (1980KH09, 1982GUZS; theor.).

45. (a) ¹²C(³He, ³He)¹²C
(b) ¹²C(³He, pd)¹²C Q_m = -5.4936

Angular distributions of ³He ions have been measured in the range E(³He) = 2 to 217 MeV: see (1968AJ02), Tables 12.22 (in PDF or PS) in (1975AJ02), 12.17 (in PDF or PS) in (1980AJ01) and 12.17 (in PDF or PS) here. Parameters of observed ³He groups are displayed in Table 12.19 (in PDF or PS).

Angular distributions of the ³He groups to ¹²C*(15.11, 16.11, 16.58, 19.56) have been compared with those for the tritons to ¹²N*(0, 0.96, 1.19, 4.25) in the analog (³He, t) reaction: the correspondence is excellent and suggests strongly that these are T = 1 isobaric analog states. See also Tables 12.12 (in PDF or PS) in (1980AJ01) and 12.19 (in PDF or PS) here. ¹²C*(4.4, 15.2, 18.4, 18.9, 21.3, 23.5, 25.9, 28.8) all appear to correspond to E2 transitions: their strengths add up to 46% of the EWSR (energy-weighted sum rule). See (1980AJ01) for references. (1980LE25) have reported states at E_x = 9.15 ± 0.2 and 20.3 ± 0.2 MeV [Γ = 1.8 ± 0.2 and 1.1 ± 0.2 MeV, respectively]: it is suggested that both are E0 states whose intensities are (2.1 ± 0.4) and (2.6 ± 0.2)% of the EWSR: see, however, (1981EY02) in reaction 46.

For reaction (b) see (1983DR06; E(³He) = 33 MeV) and (1980MA07; E(³He) = 90 MeV). See also (1983CA07). See also ¹⁵O in (1981AJ01), (1979KA1G), (1982TA05) and (1977MA44, 1979BE1Q, 1982GU1J, 1984EV1C; theor.).

46. (a) ¹²C(α, α)¹²C
(b) ¹²C(α, 2α)⁸Be Q_m = -7.3665
(c) ¹²C(α, ⁸Be)⁸Be Q_m = -7.4583

Angular distributions have been measured at many energies up to 1.37 GeV: see Tables 12.24 (in PDF or PS) in (1968AJ02), 12.22 (in PDF or PS) in (1975AJ02), 12.17 (in PDF or PS) in (1980AJ01) and 12.17 (in PDF or PS) here. Parameters of observed states of ¹²C are displayed in Table 12.19 (in PDF or PS). The quadrupole deformation parameter β₂ is -0.29 ± 0.02, -0.30 ± 0.02 [see (1980AJ01)], -0.40 ± 0.02 (1983YA01), while β₃ ≈ 0.23 [see (1980AJ01)] and β₄ = +0.16 ± 0.03 (1983YA01; see also for a review of deformation parameters).

Angular correlation measurements (α₁, γ_4.4) have been carried out for E_α = 10.2 to 104 MeV [see (1980AJ01)] and at 14 to 19 MeV and at 25.3 MeV (1978AL20), as well as at 19.3 to 30.7 MeV (1981BU21). At E_α = 104 MeV, the sum of the E2 strength in the dominant decay channels [α₀ + α₁ + p₀] for 20 < E_x < 30 MeV exhausts less than 15% of the EWSR (1978RI03). At E_α = 150 MeV, the observed isoscalar E2 strength is (6 ± 2)% of the EWSR (1976KN05).

At E_α = 104 MeV (1981EY02) report no evidence for E0 strength in the region of a state at E_x = 9.15 MeV (1980LE25) reported in reaction 45. There is no evidence for concentrated E0 strength above E_x = 7.7 MeV (1981EY02). See also (1981YO04).

Reaction (b) has been studied for E_α up to 700 MeV [see (1975AJ02)] and at E_α = 65 MeV (1983YA01) and 140 MeV (1980WA07). For cross-section measurements (reaction (a)) of the transitions to ¹²C*(0, 4.4, 7.7, 9.6) at E_α = 24 MeV see (1983SAZL). For spallation work at 1.6, 4.2 and 8.4 GeV see (1983AN13). For pion production see (1981AB04, 1982AN1H, 1983MO14). For reaction (c) see (1981RU10) and (1980AJ01). See also ¹⁶O in (1982AJ01, 1986AJ04), (1982AB1K, 1983GUZS, 1983ZH09, 1984GU1E, 1984LE1E), (1978BE1G, 1979DE1P, 1979MA1V, 1979PA21), (1979RA1C; astrophys.) and (1977MA44, 1978GU23, 1979GH01, 1979GO24, 1979KR08, 1979PA18, 1979ZE06, 1980IH01, 1980AM1C, 1980BA1Z, 1980KH09, 1980LI09, 1980LI1K, 1980NI11, 1980VI01, 1980WA1G, 1980WO1D, 1981BA20, 1981DA1H, 1981DY02, 1981DY1C, 1981DY1D, 1981GR17, 1981GU1B, 1981KA04, 1981LA13, 1981LI1V, 1981MA1L, 1981MA42, 1981SU05, 1981WA1M, 1981WO1D, 1981ZE01, 1982BU1D, 1982CA1B, 1982GE1A, 1982GUZS, 1982IN03, 1982JA07, 1982NI1B, 1983AH04, 1983BU15, 1983LI1P, 1983SM1B, 1984BA30, 1984BU1M, 1984BU1R, 1984GO04, 1984KH01, 1984NA11, 1984SA1T; theor.).

47. (a) ¹²C(⁶Li, ⁶Li)¹²C
(b) ¹²C(⁶Li, αd)¹²C Q_m = -1.4753
(c) ¹²C(⁷Li, ⁷Li)¹²C

The elastic scattering in reaction (a) has been studied at E(⁶Li) = 4.5 to 100 MeV [see (1975AJ02, 1980AJ01)] and 20 to 156 MeV [see Table 12.20 (in PDF or PS) here]. At E(⁶Li) = 36.4 and 40 MeV (1974BI04) have studied the inelastic angular distributions to ¹²C*(4.4, 7.7, 9.6, 10.8, 11.8, 12.7, 13.4, 14.1) and have calculated deformation parameters under various assumptions. Reaction (b) at E(⁶Li) = 60 MeV takes place via ¹²C*(0, 4.4, 7.7) (1982AR20). See also ¹⁶O in (1982AJ01, 1986AJ04).

The elastic scattering in reaction (c) has been studied at E(⁷Li) = 4.5 to 89 MeV [see (1975AJ02, 1980AJ01)] and 34 to 78.7 MeV [see Table 12.20 (in PDF or PS) here]. For fusion and yield measurements see (1980FU06, 1982DE30, 1982TA23). For pion production see (1982AS1B). For a polarization study see (1984MO06). See also ¹⁸F, ¹⁹F in (1983AJ01), (1981BYZZ, 1983KA1T), (1979MA1T, 1979KN1A, 1983BI13) and (1979SU1F, 1980KH09, 1980ST22, 1981DY02, 1981GR17, 1981ME1E, 1981ME1F, 1981OS1D, 1981TH07, 1982CO16, 1982DE28, 1982DR1D, 1982GU21, 1982MA35, 1982RA22, 1983BU15, 1983KH1A, 1983OS03, 1983SH24, 1984BR08, 1984GR05, 1984SA1B; theor.).

48. ¹²C(⁹Be, ⁹Be)¹²C

Angular distributions have been obtained at E(⁹Be) = 14 to 43.8 MeV, E(¹²C) = 12 to 21 MeV [see (1980AJ01)] and at E(⁹Be) = 20 to 158.3 MeV: see Table 12.20 (in PDF or PS). For fusion and yield measurements see (1981JA09, 1982DEZL, 1982HU06, 1983JA09). See also (1982JA1E, 1983DU13) and (1980BR05, 1980OH1B, 1981GR17, 1981HU07, 1982GU21, 1982LO13, 1983DE1U, 1983KA17, 1983OH04; theor.).

49. (a) ¹²C(¹⁰B, ¹⁰B)¹²C
(b) ¹²C(¹¹B, ¹¹B)¹²C

Angular distributions for reaction (a) have been measured at E(¹⁰B) = 18 and 100 MeV. Elastic angular distributions in reaction (b) have been studied at E(¹²C) = 15 to 87 MeV. See (1980AJ01) and Table 12.20 (in PDF or PS) here. For fusion cross-section and excitation-function studies see (1979FR05, 1981MA18, 1982MA20, 1983MA53, 1984MAZZ). See also (1979SH22), (1978BE1G, 1982FR1T, 1983BI13, 1983DU13) and (1978DZ1A, 1979IS07, 1979ZE1B, 1981DE13, 1981YO05, 1982FR1T, 1982HA42, 1983HA1E; theor.).

50. ¹²C(¹²C, ¹²C)¹²C

Angular distributions have been measured at E(¹²C) = 10 to 174 MeV [see (1980AJ01)] and at 12 MeV to 1.02 GeV (see Table 12.20 (in PDF or PS)). Single and mutual inelastic scattering to ¹²C*(4.4) have been studied by the angular correlation method by (1979CA13, 1981BA21; E(¹²C) = 29 to 64 MeV). For pion production see (1980BA1V, 1981AL1K, 1981AN1D, 1981GA1F, 1981NA1E, 1982AS1B, 1982BO1L, 1982GRZW, 1982JO1A, 1983AG1D, 1983MO14, 1984BR01, 1984NO02). For fusion, yields and cross-sectionmeasurements, see (1978CO05, 1978CO20, 1978HA1F, 1978TR08, 1979KO19, 1979KO20, 1979LE14, 1979TRZQ, 1979UZ1A, 1980BE1U, 1980BE1V, 1980CH1K, 1980CO03, 1980DE28, 1980FU01, 1980KE15, 1980KO02, 1980KO03, 1980PA19, 1980SK1A, 1980TR07, 1980TR06, 1980WI1F, 1980ZY1A, 1981BR03, 1981HE08, 1981MC13, 1981MO20, 1981NA1E, 1981PE01, 1982BE54, 1982BR20, 1982DA16, 1982DE48, 1982HO1F, 1982KA1W, 1982ME05, 1982PE11, 1982SA27, 1982ZUZZ, 1983AN13, 1983BR1N, 1983DE1Y, 1983HAZI, 1983LE05, 1983ME22, 1983NO1E, 1983SH26, 1983SIZY, 1983TR07, 1983WI11, 1984FU02, 1984TR01).

51. (a) ¹²C(¹³C, ¹³C)¹²C
(b) ¹²C(¹⁴C, ¹⁴C)¹²C

Angular distributions for reaction (a) have been studied at E(¹²C) = 15 to 87 MeV and E(¹³C) = 12 and 36 MeV [see (1975AJ02)] and at E(¹²C) = 15 MeV [elastic; see (1980VO05)] and E(¹³C) = 87 MeV (1981TA21; to ¹²C*(4.4)). Elastic angular distributions in reaction (b) are reported at E(¹²C) = 12 to 20 MeV: see (1980AJ01). For a study of the spin-flip probability to ¹²C*(4.4) see (1981TA21). See also (1984BYZZ). For fusion, yield and cross-section measurements see (1979KO20, 1980FR03, 1981HE08, 1982DA16, 1983FR04, 1983HAZI). See also (1981PL1C, 1982KO2B), (1981ST1P, 1982FR1U, 1983BI13, 1983DU13, 1983VO1J) and (1979GR20, 1979IM02, 1979ZE1B, 1980BA54, 1981HA18, 1982LO13, 1982OH05, 1982VO1F, 1983CI08, 1983DE1U, 1983FR23, 1983HU1C, 1983LA1E; theor.).

52. (a) ¹²C(¹⁴N, ¹⁴N)¹²C
(b) ¹²C(¹⁵N, ¹⁵N)¹²C

Angular distributions (reaction (a)) have been measured at E(¹⁴N) = 21 to 155 MeV (at certain energies involving ¹²C*(4.4, 9.6) as well as the elastic scattering) [see (1975AJ02, 1980AJ01)] and at 37, 47 and 58.3 MeV (1978CO20) and 48 MeV (1983QU02; g.s., 4.4) and 78.8 MeV (1979MO14; g.s.).

Angular distributions (reaction (b)) are reported at E(¹⁵N) = 31.5 to 47 MeV [see (1980AJ01)] and at 31.5, 36.5, 39.5 and 47 MeV (1978CO20) as well as at 94 MeV (1981TA21; ¹²C*(4.4)). The SFP (transition to ¹²C*(4.4)) has been studied by (1981TA21). For fusion, yields and cross sections see (1978CO20, 1979KO20, 1980TA1B, 1980WI09, 1981CO11, 1981DIZW, 1982NO12, 1983CA1N, 1983DA10). See also (1978HA1F), (1979NA1G, 1981ST1P, 1983BI13, 1983DU13, 1984GO05) and (1979MO1J, 1980LE11, 1980LO02, 1980VA03, 1981CH23, 1981CU06, 1981DE13, 1981VA1E, 1981VA1H, 1982BL12, 1982HA42, 1982HA56, 1982HU1G, 1982LO13, 1983CI08, 1983GO13; theor.).

53. (a) ¹²C(¹⁶O, ¹⁶O)¹²C
(b) ¹²C(¹⁶O, α)¹²C¹²C Q_m = -7.1620

Angular distributions have been measured at E(¹⁶O) = 17.3 to 315 MeV and at E(¹²C) = 65 to 76.8 MeV [see (1975AJ02, 1980AJ01)] and at E(¹⁶O) = 21 to 315 MeV [see Table 12.20 (in PDF or PS)]. The excitation of ¹²C*(0, 4.4, 14.1, 26) has been reported.

(1979DO01) present evidence for the excitation of giant resonances in a number of nuclei including ¹²C: ¹²C*(25.3 - 26.7) (Γ ≈ 4 MeV) contain (25⁺¹⁵_-10)% of the E2 strength. The m-state populations in the transition to ¹²C*(4.4) have been studied at E_c.m. = 19 to 22.6 MeV (1980BE02) and 19.7 and 23.6 MeV (1983KA01). Angular correlation measurements involving ¹⁶O*(6.13) are reported by (1979JA25, 1980JA06). See also (1984PO01) and ¹⁶O in (1986AJ04). Reaction (b) has been studied at E(¹⁶O) = 25.96 MeV (1983GE09), 140 MeV (1980RA12, 1981RA20) and 142.4 MeV (1983SH26: ¹²C*(0, 4.4) are involved, as are a number of ¹⁶O states. See also (1983KA10, 1984MU04).

For fusion, yield and cross-section measurements see (1979JA25, 1979KO03, 1979KO20, 1979LUZW, 1980BE02, 1980FR10, 1980FR05, 1980JA06, 1980TA1B, 1981BR05, 1981FU05, 1981SCZX, 1981TA24, 1982BR1P, 1982CO22, 1982FR04, 1982HUZV, 1982PR1A, 1982SAZL, 1982ST11, 1982WI04, 1983CA1N, 1983CHZX, 1983FR02, 1983GE09, 1983GO11, 1983KA01, 1983KL1A, 1983LA07, 1983ME04, 1983ME10, 1983RE1C, 1983SAZQ, 1983SC29, 1983VO1A, 1984BE22, 1984HU02, 1984MU04). For pion production see (1983NO1E).

54. (a) ¹²C(¹⁷O, ¹⁷O)¹²C
(b) ¹²C(¹⁸O, ¹⁸O)¹²C

The elastic scattering angular distributions have been measured at E(¹⁷O) = 30.5 to 35 MeV and at E(¹⁸O) = 32.3 to 57.5 MeV [see (1980AJ01)] and at E(¹⁸O) = 32.0 to 140 MeV (1982HE07). For reaction (b) see also (1984BH01) in ¹⁸O in (1987AJ02). For fusion, yields and cross-section measurements see (1979DAZK, 1979KO20, 1980WI09, 1982BA49, 1982HE07, 1983CA1N, 1983VO1B). See also (1980HE11, 1983BI13) and (1980CH1J, 1980LE11, 1980LO02, 1980VA03, 1981HA18, 1982GI1C, 1982LO13, 1983CI08, 1983MA29, 1984AB1F; theor.).

55. ¹²C(¹⁹F, ¹⁹F)¹²C

Elastic angular distributions have been measured at E(¹⁹F) = 40, 60 and 68.8 MeV [see (1980AJ01)], at 18.0, 20.7, 21.5 and 22.3 MeV (1981MAZJ) and at E(¹²C) = 30.0, 40.3, 50.0 and 60.1 MeV (1984TA08). See also ¹⁹F in (1983AJ01). For fusion and yield measurements see (1979KO20, 1981MAZJ). See also (1980CO08, 1982MA2E), 1983BI13 and (1980LO02, 1982GI1C, 1982LO13, 1983CI08; theor.).

56. (a) ¹²C(²⁰Ne, ²⁰Ne)¹²C
(b) ¹²C(²²Ne, ²²Ne)¹²C

Elastic angular distributions (reaction (a)) have been measured at E(¹²C) = 37 MeV and E(²⁰Ne) = 65.7 MeV [see (1980AJ01)] as well as at E(¹²C) = 20 to 34.4 MeV (1983RI13), 60.7 and 72.6 to 75.2 MeV (1982SH29; also ²⁰Ne*(0, 1.6)) and 77.4 MeV (1979MO14). See also (1979FO22). For fusion, yields and breakup measurements see (1978TR08, 1979FO22, 1979SA26, 1979SH18, 1980HU12, 1980SK1A, 1980TS03, 1981DE20, 1981OS07, 1981ST20, 1982DE10, 1982KO29, 1982MO15, 1982SH29, 1983RI13). For pion production see (1979NA12, 1982AN1H, 1982RA1D). See also ²⁰Ne in (1983AJ01), (1980CO08, 1980MA1T, 1983OS1J), (1979GO1C, 1981SC1J, 1983BI13, 1983DU13 [also on ²³Na], 1983HE1B), (1981RO1W; astrophys.) and (1978VO13, 1980OH05, 1981AB1A, 1981AN1D, 1981VA1E, 1982LO13, 1983CI08, 1983TO1L; theor.).

57. (a) ¹²C(²⁴Mg, ²⁴Mg)¹²C
(b) ¹²C(²⁶Mg, ²⁶Mg)¹²C

Elastic angular distributions (reaction (a)) have been measured at E(¹²C) = 20 to 36 MeV (1979CH24), 20 to 60 MeV (1982DA09), 24.8, 27.7 to 34.8 MeV (1981ME10) and 40 MeV (1982LI16). In reaction (b) these have been studied at E(¹²C) = 20 to 56 MeV (1982DA09). For fusion, yields and breakup measurements see (1979CH24, 1979FO22, 1981ME10, 1982DA09, 1982GA09, 1982ME06, 1983GL1E, 1983ROZZ). See also (1982FR1T, 1983BI13, 1983BR1R, 1983DU13) and (1980TA1E, 1983HU1C, 1984HU05; theor.).

58. ¹²C(²⁷Al, ²⁷Al)¹²C

Elastic angular distributions have been measured at E(¹²C) = 30.0 to 39.9 MeV (1979RO11), while that of the transition to ¹²C*(4.4) has been studied at E(¹²C) = 82 MeV (1977BE42). For fusion, yield and breakup measurements see (1979RO11, 1979WU1A, 1980WU1C, 1981WU1B, 1983ROZZ). For pion production see (1982AS1B). See also (1980TA1B, 1983BI13, 1983DU13) and (1981CH23, 1982BL12, 1982GI1C, 1983FR08, 1983SH1V, 1983XI1A; theor.).

59. (a) ¹²C(²⁸Si, ²⁸Si)¹²C
(b) ¹²C(²⁹Si, ²⁹Si)¹²C
(c) ¹²C(³⁰Si, ³⁰Si)¹²C

Elastic angular distributions have been studied for reaction (a) at E(¹²C) = 19 to 186.4 MeV and at E(²⁸Si) = 58.3 to 116.7 MeV [see (1980AJ01)] as well as at E(¹²C) = 19 to 48 MeV (1979CH25), 41.3 MeV (1979BA32), 56.0 to 69.5 MeV (1983SH1Y) and 131.5 MeV (1980SA25). For fusion, yield and breakup measurements see (1979BA49, 1979CH25, 1979JO07, 1979KU09, 1980SK1A, 1981BR13, 1981VA01, 1982CH02, 1982GA09, 1982LE04, 1982NA21, 1982SH16, 1983RA26, 1983ROZZ, 1983ZH1E). See also (1979RO11, 1983SC1H, 1983SC1J), (1978ST1F, 1979DE1N, 1980ER1D, 1980SA25, 1982BR1T, 1982ER1F, 1983BI13, 1983BR1R, 1983DU13) and (1978FI1D, 1978FR1B, 1980BA44, 1980FR1F, 1980HU09, 1980TA1E, 1981FR12, 1981HU07, 1981VA1H, 1982BRZE, 1982HA29, 1982HU04, 1982HU1G, 1982KH04, 1982SM1D, 1983HA39, 1983SA1D, 1983SI07; theor.).

60. ¹²C(³²S, ³²S)¹²C

Elastic angular distributions are reported at E(¹²C) = 35.8 MeV and E(³²S) = 73.3 to 128.3 MeV [see (1980AJ01)] and at E(³²S) = 60 to 99 MeV (1982CH02) and 160 MeV (1983GI12). For fusion and yield measurements see (1982CH02, 1983RAZY). See also (1979DE1N, 1982BR1T, 1983DU13 [also on ³¹P, ³⁴S, ³⁵S, ³⁵Cl, ³⁷Cl, ³⁶Ar, ³⁸Ar], 1983GI12) and (1982BRZE; theor.).

61. ¹²C(³⁹K, ³⁹K)¹²C

Elastic angular distributions have been studied at E(¹²C) = 54 and 63 MeV (1980GL03). See also (1983DU13; also on ⁴⁰K).

62. (a) ¹²C(⁴⁰Ca, ⁴⁰Ca)¹²C
(b) ¹²C(⁴²Ca, ⁴²Ca)¹²C
(c) ¹²C(⁴⁸Ca, ⁴⁸Ca)¹²C

The elastic scattering in reactions (a), (b) and (c) has been studied at E(¹²C) = 51.0, 49.9 and 49.9 MeV, respectively (1979RE03). For fusion, yield and cross section measurements see (1980KU03, 1983RAZY, 1983ROZZ) and (1980AJ01). See also (1980PE1D), (1979DE1N, 1981SC1N, 1983DU13 [ also on ⁴³Ca, ⁴⁶Ca]) and (1979SA27, 1980GL03, 1982AL02, 1982BRZE, 1982KH04, 1983SH1V, 1983XI1A; theor.).

63. ¹²N(β⁺)¹²C Q_m = 17.338

The decay is mainly to the ground state via an allowed transition. Branching ratios to other states of ¹²C are displayed in Table 12.21 (in PDF or PS). The half-life of ¹²N is 11.000 ± 0.016 msec (1978AL01). See also (1968AJ02). The ratio of the branching ratios ¹²N/¹²B for the decays to ¹²C*(4.4) is 1.607 ± 0.021 (1981KA31). This leads to the following values for the mirror asymmetries of ¹²B and ¹²N for decay to ¹²C*(0, 4.4): δ_g.s. = +0.129 ± 0.008 (1978AL01), δ_4.4 = -0.001 ± 0.014 (1981KA31). The results displayed here as well as in ¹²B (see reaction 29 and Table 12.14 (in PDF or PS) in ¹²C) are consistent with the absence of SCC contributions and are in agreement with CVC: see reaction 69 in (1980AJ01). See also (1980OK01, 1980SY02, 1981HO06; theor.).

64. ¹³C(γ, n)¹²C Q_m = -4.9463

The decay of the giant resonance in ¹³C takes place predominantly to ¹²C*(15.1, 16.1) [and to their analogues in ¹²B]. Below E_γ = 21 MeV transitions to ¹²C*(4.4) are dominant: see (1980AJ01). See also (1979WO06, 1980HO11, 1983ZU02) and ¹³C in (1981AJ01, 1986AJ01).

65. ¹³C(π⁺, p)¹²C Q_m = 135.4033

Angular distributions have been measured at E_π⁺ = 90 and 170 MeV to ¹²C*(0, 4.4, 7.7, 9.6, 12.7, 14.1, 15.1, 16.1, 19.1, 20.6, 22.9, 25.3) (1981AN10): an energy-dependent ratio for the excitation of ¹²C*(12.7, 15.1) is reported. Similarities in the population of states seen in this reaction and in the (p, d) reaction are observed (1981AN10). Angular distributions at E_π⁺ = 32 MeV are also reported (1982DO01; g.s., 4.4). See also (1982HO1C, 1982LO1B).

66. (a) ¹³C(p, d)¹²C Q_m = -2.7218
(b) ¹³C(p, 2pd)¹⁰Be Q_m = -29.9066

Angular distributions have been measured at E_p = 8 to 54.9 MeV [see (1980AJ01)] and at E_{pol. p} = 65 MeV (1980HO18, 1982KA01; ¹²C*(0, 12.7, 15.1, 16.1); see also for C²S), 200 and 400 MeV (1981LI06; ¹²C*(0, 4.4)), and at E_p = 800 MeV (1980BA02; ¹²C*(0, 4.4, 12.7, 14.1, 15.1, 16.1)). See also (1980KA01, 1981IR1A, 1982MA1H, 1983BEYY). For yields and polarization measurements see (1980HO18, 1981LI06, 1982BU03) and ¹⁴N in (1981AJ01, 1986AJ01).

At E_p = 62 MeV the excitation of states with E_x = 15112 ± 5, 16110 ± 5 [< 20], 17760 ± 20 [80 ± 20], 18800 ± 40 [80 ± 30], 21500 ± 100 [< 200] and 22550 ± 50 [< 200] keV has been reported [the numbers shown in brackets are Γ_c.m., in keV]; l_n = 1 for all states except ¹²C*(21.5) and (22.55) for which l_n = (1) and ≠ 1, respectively: see (1980AJ01) for references.

At E_p = 800 MeV an enhancement is observed in the yield of forward emitted deuterons (reaction (b)) which correspond to an E_x of 241 MeV in ¹²C. It is suggested that it may be due to the formation of low-spin (ΔN^-1) states in ¹²C (1983MO04). See also (1980CA1A, 1982LO1B, 1982YA1A, 1984PEZW) and (1980BA54, 1980SH1J, 1983DI1C, 1983TO10; theor.).

67. ¹³C(d, t)¹²C Q_m = 1.3110

Angular distributions have been studied at E_d = 0.41 to 27.5 MeV [see (1975AJ02, 1980AJ01)] and at E_d-bar = 29 MeV (1979CO08; to ¹²C*(0, 4.4, 12.71, 15.11, 16.11) [see also ¹³C(d, ³He) in ¹²B]. For charge-dependent matrix elements between ¹²C*(12.71, 15.11) see Table 12.10 (in PDF or PS). See also (1979SHZH), (1983AD1B) and (1980BA54, 1980LE14; theor.).

68. (a) ¹³C(³He, α)¹²C Q_m = 15.6314
(b) ¹³C(³He, 2α)⁸Be Q_m = 8.2649

Angular distributions have been measured at many energies up to E(³He) = 45 MeV [see (1980AJ01)] as well as at 18.3 and 23.1 MeV (1982GU12; α₀, α₁). Angular correlations involving ¹²C*(15.1) have been studied at E_α = 24 and 25.5 MeV: the average ratio between the p_1/2 and p_3/2 amplitudes is -0.086 ± 0.030 (1980BA1U; prelim.). For the earlier work see (1980AJ01).

A study of reaction (b) leads to Γ_α/Γ for ¹²C*(15.11) = (4.1 ± 0.9)%; together with the other parameters for the decay of the state (see Table 12.7 (in PDF or PS)) this leads to Γ_α = 1.8 ± 0.3 eV. If this isospin forbidden α-width is the result of the mixing between ¹²C*(12.71, 15.11) via a charge-dependent interaction the matrix element is 340 ± 60 keV: see, however, Table 12.10 (in PDF or PS). See also (1978MO34, 1984LE1E, 1984VA1J), and (1981KA1K) in ¹⁶O in (1982AJ01).

69. (a) ¹³C(⁶Li, ⁷Li)¹²C Q_m = 2.3037
(b) ¹³C(⁷Li, ⁸Li)¹²C Q_m = -2.9136

At E(⁷Li) = 34 MeV angular distributions have been observed for the reactions to ¹²C*(0, 4.4) + ⁷Li*(g.s., 0.48) and ⁸Li*(0, 0.95) in all combinations. While ¹²C*(0, 4.4) are dominant in the two spectra, ¹²C*(7.7, 9.6) and, in reaction (a) at E(⁶Li) = 36 MeV, ¹²C*(12.7) are also populated (1973SC26).

70. ¹³C(¹³C, ¹⁴C)¹²C Q_m = 3.2302

Angular distributions have been reported at E(¹³C) = 16.0 to 50.0 MeV by (1983KO15) who have also studied the excitation functions over that energy range. See also (1981BR1P) and (1983KO16; theor.).

71. (a) ¹³C(¹⁶O, ¹⁷O)¹²C Q_m = -0.8025
(b) ¹³C(¹⁷O, ¹⁸O)¹²C Q_m = 3.0977
(c) ¹³C(¹⁸O, ¹⁹O)¹²C Q_m = -0.989

Angular distributions for reaction (a) have been measured at E(¹⁶O) = 13 to 46.0 MeV: see (1980AJ01). See also (1980RA12) in ¹⁶O in (1986AJ04), as well as (1979GO1C) and (1980GO1L, 1980PA04; theor.). For reactions (b) and (c) see (1980AJ01) and (1983OS08; theor.).

72. ¹⁴C(p, t)¹²C Q_m = -4.6410

Angular distributions have been measured at E_p = 14.5, 18.5 and 39.8 MeV: see (1975AJ02). At E_p = 54 MeV angular distributions are reported to two states at E_x = 27.57 ± 0.03 and 29.63 ± 0.05 MeV [Γ_c.m. ≲ 200 keV]: their identification as the first T = 2 states is supported by the similar angular distributions to the first two T = 2 states in ¹²B, reached in the (p, ³He) reaction [see reaction 24 in ¹²B]. The lower T = 2 state is well fitted by L = 0; the angular distribution to ¹²C*(29.63) is rather featureless. It is suggested that its shape is somewhat more consistent with L = 0 than with L = 2 (1976AS01): [(1976BA24) has suggested that the second T = 2 state in A = 12 may have J^π = 0⁺.] It is not excluded that the group to ¹²C*(29.63) may be due to unresolved states (1976AS01). (1976AS01) report Γ_p/Γ ≈ 0.3 ± 0.1 and Γ_α₁/Γ < 0.1 for the first T = 2 state and Γ_p/Γ = 0.8 ± 0.2, Γ_p₀/Γ ≈ 0.4 and Γ_α/Γ ≈ 0.2 for ¹²C*(29.63). (1978RO08) report E_x = 27595.0 ± 2.4 keV, Γ ≤ 30 keV for the first T = 2 state and calculate the decay properties for two values of total width, 0 and 30 keV. Branching ratios for the decays to ⁸Be(0) + α; ¹¹B*(0, 2.12, 4.45, 5.02, 6.74 + 6.79) + p; and ¹⁰B(0) + d are, respectively, (10.5 ± 3.0), (3.0 ± 2.2), (8.0 ± 2.3), (0 ± 3.3), (8.4 ± 3.2), (8 ± 5), and (2.8 ± 2.0)% (1979FR04).

73. ¹⁴C(¹⁶O, ¹⁸O)¹²C Q_m = -0.9349

Angular distributions to the ground states have been measured at E(¹⁶O) = 20, 25, 30 and 32 MeV: see (1980AJ01).

74. ¹⁴N(n, t)¹²C Q_m = -4.0151

See (1980AJ01).

75. ¹⁴N(p, ³He)¹²C Q_m = -4.7788

Angular distributions have been studied at E_p = 7.5 to 52 MeV [at the higher energies to ¹²C*(12.7, 14.1, 15.1, 16.1) as well as to ¹²C*(0, 4.4)]. (1979SHZH; prelim.) conclude on the basis of the results in this reaction and in the ¹⁴N(d, α) reaction that ¹²C*(19.6, 20.6, 22.7) are of mixed isospin (primarily T = 0) and have positive parity. See, however, Table 12.6 (in PDF or PS) for the density of states. See also (1983GO10; theor.).

76. ¹⁴N(d, α)¹²C Q_m = 13.5743

Observed α-particle groups are shown in Table 12.19 (in PDF or PS). Angular distributions have been measured at energies up to 40 MeV: see (1980AJ01). At the latter energy (1976VA07) have measured the distributions of the α-particles to ¹²C*(0, 4.4, 12.7, 14.1, 19.5, 20.6, 22.5) and suggest J^π = (1, 2, 3)⁺, (2, 3)⁺ and (2, 3)⁺, respectively, for ¹²C*(19.5, 20.6, 22.5). See also (1979SHZH) in reaction 75 and Table 12.6 (in PDF or PS). For recent polarization studies (1979DE45, 1981KR1A, 1982US1A) see ¹⁶O in (1982AJ01, 1986AJ04).

77. ¹⁴N(¹⁰B, 3α)¹²C Q_m = 7.6387

See (1978BE1G) and (1980SH04; theor.).

78. ¹⁴N(¹²C, p¹³C)¹²C Q_m = -7.5506

See (1982QU1B).

79. ¹⁴N(¹⁴N, ¹⁶O)¹²C Q_m = 10.4639

See (1983KL1A).

80. ¹⁵N(e, t)¹²C Q_m = -14.8484

See (1979UE01) in reaction 59 of ¹⁵N (1981AJ01).

81. ¹⁵N(p, α)¹²C Q_m = 4.9656

Angular distributions of α₀ and α₁ have been measured for E_p up to 43.7 MeV: see (1980AJ01). At the highest energy the angular distributions to the 0⁺ states ¹²C*(0, 7.65, 17.76) are fitted by L = 1, and L = 3 is consistent with distributions to ¹²C*(14.1, 16.1) [J^π = 4⁺ and 2⁺]. See also (1983LE25), (1983SC43; applied), (1980CA28; theor.) and ¹⁶O in (1982AJ01, 1986AJ04).

82. ¹⁵N(α, ⁷Li)¹²C Q_m = -12.3803

At E_α = 42 MeV angular distributions have been obtained for all four of the transitions involving ¹²C*(0, 4.4) and ⁷Li*(0, 0.48): see (1980AJ01).

83. ¹⁶O(γ, 2d)¹²C Q_m = -31.00869

See (1984GL1H; theor.).

84. ¹⁶O(e, e'α)¹²C Q_m = -7.1620

At E_e = 128 MeV the α-decay is primarily to ¹²C*(0, 4.4) (1983VOZX).

85. ¹⁶O(p, pα)¹²C Q_m = -7.1620

This reaction appears to proceed primarily via excited states of ¹³N and ¹⁶O to ¹²C*(4.4) [E_p = 46.8 and 50 MeV]: see (1980AJ01). The reaction has also been studied at E_p = 101.5 MeV (1981CA02; S_α relative to the (p, pα) reaction on other nuclei).

86. ¹⁶O(d, ⁶Li)¹²C Q_m = -5.6866

Angular distributions have been measured at E_d = 12.7 to 35 MeV [see (1980AJ01)], at E_d = 50, 60, 65 and 80 MeV (1979OE04; g.s., 4.4, 14.1) and at 54.25 MeV (1980YA02; g.s., 4.4, 7.7, 9.6, 14.1). Both of the latter groups performed a FRDWBA analysis of their data. (1980YA02) derive S_α = 0.57, 1.50, 0.09, 0.05, 0.83 for ¹²C*(0, 4.4, 7.7, 9.6, 14.1). See also (1979OE04, 1984NE1A) and (1980AJ01).

87. ¹⁶O(³He, ⁷Be)¹²C Q_m = -5.5744

Angular distributions have been studied at E(³He) = 30 MeV (¹²C*(0, 4.4, 7.7, 9.6) and ⁷Be*(0, 0.4)) and 70 MeV (¹²C*(0, 4.4) and ⁷Be*(0, 0.4)) [see for S_α] [see (1980AJ01)], as well as at 41 MeV [see (1981LE01)].

88. (a) ¹⁶O(α, 2α)¹²C Q_m = -7.1620
(b) ¹⁶O(α, ⁸Be)¹²C Q_m = -7.2537

At E_α = 90 MeV angular distributions involving ¹²C*(0, 4.4) (reaction (a)) have been analyzed by PWIA and DWBA by (1976SH02): S_α = 2.9 ± 0.5 and 0.70 ± 0.23, respectively. At E_α = 65 MeV angular distributions involving ⁸Be_g.s. (reaction (b)) and ¹²C*(0, 4.4, 7.7, 9.6, 14.1) have been measured by (1976WO11) [the ground-state distributions have also been studied for E_α = 55 to 72.5 MeV]: S_α = 0.25, 1.07, 0.05, 1.40 for ¹²C*(0, 4.4, 7.7, 14.1). See also (1980BE04), (1980WE1D), (1983FR14) in ¹⁶O (1986AJ04), and (1981BA20; theor.).

89. (a) ¹⁶O(¹⁶O, ²⁰Ne)¹²C Q_m = -2.428
(b) ¹⁶O(¹⁶O, 2α¹²C)¹²C Q_m = -14.3239

For reaction (a) see ²⁰Ne in (1983AJ01). See also (1981PO1A) and (1981KR09; theor.). For reaction (b) see (1982PE08).

90. ¹⁹F(d, ⁹Be)¹²C Q_m = 0.3009

At E_d = 13.6 MeV angular distributions have been obtained for the ⁹Be groups to ¹²C*(0, 4.4) (1981GO16). See (1980AJ01) for the earlier work.

91. ²⁰Ne(α, ¹²C)¹²C Q_m = -4.6213

Angular distributions have been measured in the range E_α = 13.4 to 20.8 MeV (1981DA13). See also ²⁰Ne in (1987AJ02).

92. ²³Na(d, ¹³C)¹²C Q_m = 0.479

See (1984GO1H; E_d = 13.6 MeV).

93. ²⁴Mg(α, ¹⁶O)¹²C Q_m = -6.7710

Angular distributions have been reported at E_α = 22.8 to 25.4 MeV and at 90 MeV: see (1980AJ01).

94. (a) ²⁴Mg(e, e'¹²C)¹²C Q_m = -13.933
(b) ²⁸Si(e, e'¹⁶O)¹²C Q_m = -16.755

For (a) see (1979CA1E); for (b) see (1980SC1F; theor.).