(See Energy Level Diagrams for 12C)
Shell model: (1977ME05, 1978RA1B, 1979HA59, 1979IN05, 1980CA12, 1980GI05, 1980HA35, 1980OH07, 1981AM08, 1981BO1Y, 1981DE2G, 1981LU1B, 1981RA06, 1982AR03, 1982BA52, 1982BR08, 1983VA31, 1984DE04, 1984VA06).
Cluster model: (1978RE1A, 1978TA1A, 1978UE02, 1979GO24, 1979GR1F, 1979KA21, 1979UE03, 1980BE58, 1980FU1H, 1980HA38, 1980IK1B, 1980KR1D, 1980TO1E, 1981CH1E, 1981EL1C, 1981KA03, 1981KA1P, 1981KH1F, 1981KN12, 1981MA1G, 1981NO13, 1982MA38, 1982SA1P, 1982SC1K, 1982SH01, 1982SU1B, 1982SU06, 1982VA11, 1983CA12, 1983CO1T, 1983GI06, 1983GL1C, 1983KA1K, 1983LI18, 1983PO03, 1983RO1G, 1983SA12, 1983SH38, 1984GA1P).
Special states: (1978RA1B, 1978TA1A, 1978UE02, 1979BO24, 1979DE1K, 1979HA53, 1979IN07, 1979IN05, 1979KA40, 1979KA1M, 1979KI10, 1979KU1D, 1979UE03, 1979WI1B, 1979WU1C, 1980CA12, 1980DE04, 1980FU1H, 1980HA35, 1980KI1F, 1980KR1D, 1980OH07, 1980PE05, 1980RI06, 1980SH1N, 1980SP04, 1981AM08, 1981BO1Y, 1981DE2G, 1981GR14, 1981GR15, 1981KA03, 1981RA06, 1981SE03, 1982BA52, 1982BA37, 1982BE1Z, 1982BR08, 1982IN01, 1982LE15, 1982MA38, 1982SA1P, 1982SH01, 1983AD1B, 1983AH1A, 1983AR07, 1983AU1A, 1983AU1B, 1983BA62, 1983GO1R, 1983NA1J, 1983RA1L, 1983SA12, 1983VA31, 1984CO02, 1984GO1M, 1984VA06).
Electromagnetic transitions: (1979KA40, 1979KU1D, 1979UE03, 1980DE04, 1980DE14, 1980DE45, 1980KO1L, 1980PE05, 1981AM08, 1981BO1Y, 1981GR14, 1981GR15, 1981LO04, 1981KN06, 1981LU1B, 1981SP1A, 1982AS03, 1982BA52, 1982BA37, 1982DE1G, 1982KO15, 1982KO22, 1982LA26, 1982SP1C, 1983LO04, 1984KU07).
Giant resonances: (1979DE1K, 1979HA1G, 1979KN1D, 1980BA1T, 1980LE25, 1981GR14, 1981KN12, 1981KO41, 1981MO12, 1982AR03, 1982BA52, 1982CA1H, 1982GO01, 1983DA23, 1983GO1B, 1983IS1F, 1983KA07, 1983NA1J, 1983OR03, 1984IS1B, 1984KL04).
Astrophysical questions: (1978VA1B, 1979BE1V, 1979GE1D, 1979LE1F, 1979MC1B, 1979PE1E, 1979RA1C, 1979SW1B, 1979TI1B, 1980CA1M, 1980CO1R, 1980GA1Q, 1980HE1D, 1980LA1G, 1980MC1G, 1980ME1B, 1980MO1L, 1980PE1F, 1981BE2K, 1981CR1B, 1981DE2C, 1981DU1E, 1981GA1C, 1981GA1H, 1981IB1A, 1981LA1L, 1981SC1M, 1981SN1B, 1981WA1N, 1981WA1Q, 1981WE1F, 1981WI1G, 1982HI1E, 1982IB1B, 1982JO1B, 1982NO1D, 1982SC1E, 1983AL23, 1983BO1F, 1983HA1P, 1983IB1A, 1983SI1B, 1983SW1A).
Complex reactions involving 12C: (1978HE23, 1978KN1C, 1979AL22, 1979BA34, 1979BA2A, 1979BL1E, 1979BO24, 1979BO22, 1979BU1J, 1979BU1G, 1979FR12, 1979GE05, 1979GE1A, 1979HE1D, 1979KA21, 1979KO1M, 1979LA07, 1979NA1F, 1979PO16, 1979SA27, 1979SA26, 1979SC1D, 1979ST1D, 1979TA19, 1979WI10, 1980AK02, 1980BA1G, 1980BR1P, 1980EL1D, 1980GR10, 1980GR1K, 1980ME1F, 1980MI01, 1980MO28, 1980RI06, 1980SC1G, 1980VO1D, 1981AB1G, 1981BH02, 1981BL1G, 1981BO1E, 1981BO18, 1981CE07, 1981CI03, 1981DI1A, 1981EL1B, 1981EL1F, 1981GR08, 1981HU01, 1981LO1F, 1981MA1G, 1981ME15, 1981ME13, 1981NA07, 1981ST06, 1981TA16, 1981TA22, 1981UC01, 1982BI09, 1982BU02, 1982FA1D, 1982FI1J, 1982FU04, 1982GA15, 1982HI1G, 1982IN01, 1982LY1A, 1982MO1K, 1982SH01, 1982SH21, 1982ST06, 1982TA02, 1982VI01, 1982YU1A, 1983BH09, 1983CH23, 1983CH55, 1983DE26, 1983EF1A, 1983EN04, 1983FR1G, 1983FR1A, 1983FU04, 1983GA01, 1983HA1C, 1983IS1E, 1983JA05, 1983KA1V, 1983KH04, 1983KW01, 1983LE1F, 1983MA06, 1983MO1P, 1983OL1A, 1983PAZT, 1983RA1J, 1983SA06, 1983SC1L, 1983SC1M, 1983SI1A, 1983SO08, 1983ST1A, 1983VA23, 1983WI1A, 1984AL1N, 1984BE22, 1984GR08, 1984HI1A, 1984MU1G, 1984TS03).
Muon and neutrino capture and reactions: (1977GR1C, 1979BE1G, 1979BU1H, 1979DO1E, 1979HW02, 1979HW04, 1979KI1G, 1979MA1U, 1979PA19, 1979PR1C, 1979WU10, 1980BA36, 1980CH20, 1980MU1B, 1980OR01, 1980SC18, 1981AM05, 1981BE1Q, 1981CH1B, 1981CI05, 1981EI1A, 1981ER1C, 1981GI08, 1981OH06, 1981PA1G, 1981PH1C, 1981RO05, 1981RO15, 1981RU1B, 1982BO1W, 1982DU07, 1982GU09, 1982MI05, 1982NA01, 1982RO1F, 1982RO13, 1982RU06, 1982SC11, 1983FU17, 1983GM01, 1983MO1N, 1983NO12, 1984BO1M, 1984KE1D).
Pion capture and reactions (See also reactions 31, 36, 37 and 65.): (1977MA1F, 1978AN1C, 1978AR1J, 1978EP03, 1978GO18, 1978GR1D, 1978KE09, 1978KN1C, 1978LE1G, 1978WE1C, 1979AB09, 1979AK02, 1979AL21, 1979AMZY, 1979AN1G, 1979AN1H, 1979ANZM, 1979AV1A, 1979BL07, 1979BO23, 1979BO1N, 1979BR1E, 1979BU1C, 1979CH31, 1979CO1G, 1979CO1D, 1979DA1F, 1979DA16, 1979DE1G, 1979DE2A, 1979DR09, 1979EL12, 1979EP02, 1979FR1K, 1979GE03, 1979GE07, 1979GI1C, 1979GI11, 1979GL05, 1979GL08, 1979GR1H, 1979JO08, 1979KL06, 1979KL07, 1979KO1K, 1979KO1C, 1979LI1D, 1979LU09, 1979MA1X, 1979MO15, 1979NA1F, 1979NA12, 1979NA1J, 1979OM01, 1979PE1D, 1979RA1G, 1979SI16, 1979TA19, 1979TR1B, 1979WA1G, 1979ZI05, 1980AK1B, 1980AL1D, 1980AL1G, 1980AN1D, 1980AN1Q, 1980AN1R, 1980AR01, 1980AS1A, 1980BA1R, 1980BA2P, 1980BE24, 1980BE56, 1980BR1P, 1980BU15, 1980BU19, 1980CA26, 1980CH1L, 1980CO1L, 1980CO18, 1980CR03, 1980DE04, 1980DE2A, 1980DE1V, 1980DE1X, 1980DU20, 1980ER02, 1980FR12, 1980GA12, 1980GI01, 1980GL02, 1980GO1M, 1980GO16, 1980GR1G, 1980GU22, 1980HA1F, 1980HA56, 1980HO1J, 1980HO26, 1980HO1L, 1980HO24, 1980JA11, 1980KE13, 1980KL03, 1980LA1C, 1980LE1H, 1980LE1L, 1980LI1J, 1980MA39, 1980MA2C, 1980MA1R, 1980MC03, 1980MC10, 1980MI11, 1980MO1N, 1980NA1D, 1980NA06, 1980NA11, 1980OB1B, 1980OH07, 1980OL1B, 1980PA05, 1980PE01, 1980PE1C, 1980PH02, 1980PI1B, 1980RA05, 1980SC1B, 1980SE11, 1980SI13, 1980SO03, 1980SP1A, 1980ST07, 1980ST25, 1980TH01, 1980TH1C, 1980TR1A, 1980ZA08, 1980ZI1B, 1981AB1B, 1981AK01, 1981AM02, 1981AN10, 1981AN14, 1981AN1F, 1981AN1H, 1981AS1D, 1981AS07, 1981AS1G, 1981BA2M, 1981BA2R, 1981BE1F, 1981BE63, 1981BE1N, 1981BE2P, 1981BE1X, 1981BL1E, 1981BO06, 1981BO1L, 1981BO1N, 1981BU1E, 1981BU18, 1981BU1G, 1981CH1D, 1981CH1E, 1981CO14, 1981CO1R, 1981DE01, 1981DE1R, 1981DE1U, 1981DU1H, 1981DZ03, 1981FE2A, 1981FOZV, 1981FR1F, 1981GA1F, 1981GI1E, 1981GI15, 1981GO1F, 1981GO1G, 1981GR1E, 1981GU1H, 1981HA29, 1981HAZU, 1981HO1F, 1981HU1E, 1981IO01, 1981KA05, 1981KA1N, 1981KA27, 1981KA43, 1981LE12, 1981LI1Y, 1981MA23, 1981MC09, 1981MO1D, 1981MO17, 1981NG1A, 1981NI03, 1981PE1C, 1981PI05, 1981PI1C, 1981PR02, 1981SA01, 1981SA14, 1981SC1F, 1981SE1H, 1981SEZR, 1981SI05, 1981SI09, 1981ST05, 1981ST14, 1981ST1K, 1981TH1B, 1981TO1H, 1981TO01, 1981VO1D, 1981WE1C, 1981WE1H, 1981WH01, 1981ZI01, 1982AN1J, 1982AP1A, 1982AP1B, 1982BE51, 1982BE1D, 1982BI08, 1982BL1G, 1982BO11, 1982BU20, 1982CA03, 1982CH13, 1982CH1Q, 1982DA18, 1982DA27, 1982DE1K, 1982DI1C, 1982DO01, 1982EL07, 1982ER04, 1982FR02, 1982FR16, 1982GO01, 1982GO15, 1982GO1E, 1982GOZX, 1982GR1F, 1982GRZW, 1982GR1Q, 1982GR1R, 1982HA35, 1982HE1E, 1982IL02, 1982IN1A, 1982IS10, 1982KH05, 1982LE15, 1982LI10, 1982MA1F, 1982MA1K, 1982MA22, 1982MA1U, 1982MO01, 1982MO1G, 1982MO1H, 1982MO25, 1982MO1W, 1982NA16, 1982NA18, 1982OH06, 1982OS01, 1982OS1C, 1982PI03, 1982PI1F, 1982PI04, 1982RA28, 1982SE09, 1982THZZ, 1982VO1G, 1982WE09, 1983AG1D, 1983AK03, 1983AL07, 1983AS01, 1983AS02, 1983AS1C, 1983AU1A, 1983AZ1B, 1983BA1V, 1983BA13, 1983BI1J, 1983BI1K, 1983BI1N, 1983BL08, 1983BL10, 1983BO1K, 1983CA24, 1983CE04, 1983CO08, 1983CO12, 1983DE06, 1983DE2F, 1983ER1D, 1983FR22, 1983GA17, 1983GE12, 1983GI08, 1983GU1A, 1983HE17, 1983HUZZ, 1983JE04, 1983KA19, 1983KO02, 1983MA04, 1983MA2C, 1983MA56, 1983MO1F, 1983MO1M, 1983NE1F, 1983PE14, 1983PI1A, 1983RA20, 1983RA31, 1983RI1C, 1983SC03, 1983SC11, 1983SE10, 1983SE11, 1983SH2C, 1983SH49, 1983SP06, 1983SU08, 1983TO17, 1983YO04, 1983ZA1D, 1983ZE1C, 1983ZIZZ, 1983ZI1B, 1983ZI1D, 1984BE07, 1984BU1D, 1984CO02, 1984CO1U, 1984DIZZ, 1984MIZW, 1984PO05, 1984SH02, 1984TO03).
Kaon capture and reactions (See also reaction 38.): (1978FU1F, 1978GR1D, 1978LE1G, 1978SO1A, 1979CH1H, 1979CH34, 1979DO18, 1979DU1B, 1979GS1A, 1979RA18, 1979WA1G, 1980CO04, 1980DE11, 1980DO1A, 1980DO1F, 1980DO1G, 1980EI1B, 1980HE1B, 1980HU1H, 1980KI1C, 1980PO1A, 1980RO15, 1980SA27, 1980ZA08, 1981AB1C, 1981BE45, 1981BE1T, 1981BE17, 1981BO09, 1981DA1C, 1981DE1E, 1981DO1F, 1981HU1C, 1981MI15, 1981PA16, 1981PO1F, 1981SA41, 1982AB07, 1982BA1R, 1982BA17, 1982BE1U, 1982BE1V, 1982BO1U, 1982CO1W, 1982DO1L, 1982DO1M, 1982GR1G, 1982MA16, 1982SA10, 1982WU1C, 1983AU1A, 1983BA71, 1983BA2P, 1983BE1A, 1983BR1E, 1983CH26, 1983CO1L, 1983DO1B, 1983FE07, 1983GA17, 1983GE13, 1983MA1V, 1983PO1D, 1983YA1C, 1984AM06, 1984BE07, 1984DO04, 1984MIZW, 1984SIZZ).
Hypernuclei: (1978SO1A, 1979BU1C, 1979CH1H, 1979CH34, 1979DO18, 1980DO1A, 1980IW1A, 1980KI1F, 1980MA2D, 1980PA1G, 1980PO1A, 1980ZH1C, 1981BE45, 1981BE17, 1981BO09, 1981DA1C, 1981PO1F, 1981WA1J, 1981ZH1C, 1982BA17, 1982BE1U, 1982BO1U, 1982BR1Q, 1982DO1C, 1982DO1M, 1982ER1B, 1982ER1E, 1982GR1G, 1982JO1C, 1982KA1D, 1982KO1K, 1982KO11, 1982MU1F, 1982PO1C, 1982WU1C, 1982ZH1F, 1982ZO1B, 1983AU1A, 1983BA2P, 1983BR1E, 1983FE07, 1983GA17, 1983JO1E, 1983MA1F, 1983PO1D, 1983SH38, 1983SI1E, 1983SI1H, 1983YA1C, 1983ZH1B, 1984BE07, 1984DI1B, 1984DO04, 1984MIZW, 1984SIZZ).
Other topics: (1979DO1J, 1979GA1E, 1979GO24, 1979HA53, 1979HA59, 1979KA40, 1979KA43, 1979LO13, 1979NO05, 1979WU1C, 1979ZH1B, 1980BOZN, 1980DO1A, 1980GI05, 1980HE07, 1981AU05, 1981BE1M, 1981CA1H, 1981GR15, 1981GU1C, 1981LO04, 1981MU1H, 1981PO1F, 1981ST1G, 1981ST1N, 1982BA1Q, 1982BA2G, 1982BA17, 1982BE17, 1982BO01, 1982BR08, 1982DE1G, 1982DE1N, 1982DE42, 1982LU02, 1982MU1F, 1982NG01, 1982PO1C, 1982SH1H, 1982SP1C, 1982SU06, 1982VE02, 1983AD1B, 1983AG1C, 1983AR07, 1983BO1J, 1983DA23, 1983GO1R, 1983GR26, 1983KE1E, 1983LO04, 1983SH2D, 1983WO1C, 1984CO1P, 1984DE04, 1984DU04, 1984SC1A).
Ground-state properties of 12C: (1978SH1B, 1979HA53, 1979HA59, 1979IN07, 1979JO08, 1979KA40, 1979KA1M, 1979SA27, 1979UE03, 1980BA45, 1980BOZN, 1980GI05, 1980HA38, 1980SC18, 1981AM08, 1981AT1A, 1981AV02, 1981BA2T, 1981DU16, 1981LO04, 1981KA03, 1981MO12, 1981ST1N, 1982AR03, 1982BA2G, 1982BA37, 1982BO01, 1982DE35, 1982FR01, 1982LO13, 1982MA38, 1982NG01, 1982SC11, 1982SC1K, 1982SH1H, 1982SI13, 1982ZE1A, 1983ANZQ, 1983AR07, 1983AU1B, 1983CO09, 1983CO1T, 1983FR1B, 1983GI06, 1983KU06, 1983MI08, 1983TO1L, 1983VA31, 1984BUZL, 1984MIZM, 1984WE04).
The static electric quadrupole moment of 12C*(4.4), Q2+ = 6 ± 3 e · fm2, indicating a substantial oblate deformation (1983VE01).
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).
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.).
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).
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: Ex = 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).
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.
The elastic scattering function decreases monotonically for E(3He) = 4.0 to 9.0 MeV and 15.0 to 21.0 MeV. At θc.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).
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).
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 Eα = 1.75 to 23 MeV: see (1968AJ02, 1975AJ02) for references. At Eα = 35 MeV the members of the Kπ = 0+ band and 12C*(9.63) are strongly populated (1981HAZV). See also (1981HAZW) and (1980JA1G, 1982SA1M; applied).
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 Ex = 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).
The (d, γγ) excitation function [via the Jπ = 1+, T = 1 state at Ex = 15.1 MeV] has been measured for Ed = 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).
The thin-target excitation function in the forward direction in the range Ed = 0.3 to 4.6 MeV shows some indication of a broad resonance near Ed = 0.9 MeV. Above Ed = 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 Ed = 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 Ed = 111 to 170 keV; astrophysical S-factors were also calculated. See aslo (1983SZZY; astrophys.), (1979LE1D; applied) and 11C.
Thick-target yields have been measured for Ed = 91 to 161 keV (1981CE04; also calculated astrophysical S-factor). Yields of protons have been measured for Ed = 0.14 to 12 MeV. No clear resonance structure is observed: see (1968AJ02, 1975AJ02) [see also for polarization studies]. See also 11B.
The yield of elastically scattered deuterons has been measured for Ed = 1.0 to 2.0 MeV (there is some suggestion of resonances) and for Ed = 14.0 to 15.5 MeV. Excitation functions for the deuterons to 10B*(1.74, 2.15) [Jπ; T = 0+; 1 and 1+; 0, respectively] have been measured at several angles for Ed = 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).
Excitation functions have been measured for the α0 and α1 groups for Ed = 0.4 to 12 MeV. Broad maxima in the α0 yield are reported at Ed ≈ 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 [Ex ≈ 28 MeV, Γ ≈ 4 MeV] is suggested: see (1980AJ01). For reaction (b) see 8Be in (1984AJ01) and (1980AJ01).
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).
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.
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 14Ng.s. and 12C*(0, 4.4): see (1980AJ01). See also also (1978BE1G).
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 < Ep < 14.5 MeV σ(γ0) is dominated by the giant dipole resonance at Ep = 7.2 MeV (Ex = 22.6 MeV, Γc.m. = 3.2 MeV), while the giant resonance in γ1 occurs at Ep ≈ 10.3 MeV (Ex = 25.4 MeV, Γc.m. ≈ 6.5 MeV). Absolute cross-section measurements from Ep = 5 to 14 MeV suggest that dσ/dΩ(90°L) = 13.1 ± 1.3 μb/sr be used as a standard at the Ep = 7.25 MeV peak of the GDR (1982CO11; also derived σ(E2) for Ep = 7 to 14 MeV).
A study of the giant dipole resonance region with polarized protons (Ep = 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 Jπ = 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 Ep ≈ 14.3 MeV with a cross section ≈ 2.3% that of γ0 [in γ0 yield, Eres = 15.0 MeV (1977SN01)] and perhaps as well a low-intensity structure at Ep = 11.8 MeV. The γ3 yield exhibits two asymmetric peaks at Ep = 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 Ep = 18 to 43 MeV. They report giant resonances based on various excited states of 12C at Ex = 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 Epol. p = 28.7 MeV (1980BL1B) and at Ep = 40, 60 and 80 MeV radiative capture is observed to a state, or a narrow group of states, at Ex = 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 Ep = 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 Ep = 23 to 60 MeV; γ0 and γ1 yields for Ep = 8 to 60 MeV; angular distributions (γ0, γ1) at 14.5, 17.0 and 28.7 MeV]. At Epol. p = 40 and 50 MeV analyzing powers to 12C*(0, 4.4, 9.6) and to many unresolved states with Ex to 35 MeV are reported by (1983NO1D).
(b): Excitation functions have been measured for Ep = 3.0 to 18 MeV [see (1980AJ01)] as well as at Ep = 4.5 to 7.5 MeV (1983BO19; σtot(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 Ep = 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 Ep = 35.4 keV to 10.5 MeV [see (1980AJ01)] and at 20 MeV (1981LA07). The total cross section has been measured for Ep = 35.4 to 1500 keV: it shows the 163 keV resonance and a broad peak centered at about 600 keV (σmax ≈ 0.9 b). The 163 keV resonance has σR = 54 ± 6 mb and ΓRc.m. = 5.2+0.5-0.3 keV Eres(c.m.) = 149.8 ± 0.2 keV [Ex = 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).
Ep = 0.16 MeV [12C*(16.11)]. This is the Jπ = 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 Jπ = 3- for the latter.
Ep = 0.67 MeV [12C*(16.57)]. The proton width [Γp ≈ 150 keV] indicates s-wave protons and therefore Jπ = 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 Jπ = 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.
Ep = 1.4 MeV [12C*(17.23)]. (2J + 1)Γγ0 ≥ 115 eV. This indicates Jπ = 1-, with T = 1 most probable. Jπ = 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 Γp are possible; the larger (chosen for Table 12.11 (in PDF or PS)) is favored by elastic scattering data.
Ep = 2.0 MeV [12C*(17.8)]. The resonance in the yield of α0 requires natural parity, the small α-widths suggest T = 1. For Jπ = 1- or 3- the small γ-widths would be surprising; Jπ = 2+ would lead to a larger anomaly than is observed. Jπ is then 0+, T = 1. (1982HA12) [Ep = 0.82 to 2.83 MeV] report Ex = 17.80 MeV [Γc.m. = 96 ± 5 keV] decays via a 5.10 ± 0.03 MeV γ-ray to 12C*(12.71): Γγ = 3.7 ± 1.5 eV. The angular distribution is isotropic, as expected (1982HA12).
Ep = 2.37 MeV [12C*(18.13)]. Seen as a resonance in the yield of 15.1 MeV γ-rays: σR = 0.77 ± 0.15 μb, Γc.m. = 600 ± 100 keV, (2J + 1)Γγ ≥ 2.8 ± 0.6 eV. The results are consistent with Jπ = 1+, T = 0, but interference with a non-resonant background excludes a definite assignment.
Ep = 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 lp ≥ 2. (1982HA12) report Ex = 18.38 MeV, Γc.m. ≈ 400 keV, Γγ (to 12C*(9.6)) = 5.7 ± 2.3 eV, consistent with Jπ = 3-; T = 1. The total peak cross section is 4.2 ± 1.7 μb. Transitions to 12C*(0, 4.4) are also observed: Γγ ≈ 2 x 10-3 eV and 3.2 ± 1.0 eV, repsectively.
Ep = 2.66 MeV [12C*(18.39)] is not seen here: see 11B(p, p).
Ep = 3.12 MeV [12C*(18.81)]. The angular distribution of γ0 indicates E2 radiation, Jπ = 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 Γα. The yield of γ3 (to 12C*(9.6)) shows a peak corresponding to Ex ≈ 18.9 - 19.0 MeV. It may be due to 12C*(18.8) with an energy shift due to interference (1982WR01).
The structure near Ep = 3.5 - 3.7 MeV [12C*(19.2, 19.4)] seems to require at least two levels. The large Γγ0 requires that one be Jπ = 1-, T = 1 and interference terms in σ(α0) require another to have even spin and even parity: Jπ = 2+; T = 0 is favored. (1982WR01) report that they do not observe any evidence for an isospin mixed doublet near Ex = 19.5 MeV [Ep = 2.9 to 4.6 MeV (60° and 90°)]. Resonances at Ep = 4.93 and 5.11 MeV, seen in σ(γ1) also appear in σ(α1), but not in σ(α0). Angular distributions suggest Jπ = 2+ or 3- for the latter [12C*(20.64)]; the strength of γ1 and absence of γ0 favors Jπ = 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).
Excitation functions have been reported for Ep = 2.6 to 11.5 MeV [see (1980AJ01)], from threshold to 6.0 MeV (1980RA16; σt), 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 Epol. p = 7.3 to 26.5 MeV [see (1980AJ01)] and at Epol. p = 7.0 to 16.3 MeV (1981MU1C, 1981MU1D). See also (1979BA68), (1981NO1G; applied), (1980WA1K) and (1979PH06, 1980DO01, 1980HA35, 1982RA07; theor.).
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 Ep = 1.8 to 47.4 MeV [see (1980AJ01) but note that some of the preliminary work has not been published] and more recently at Ep = 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 < Ex < 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 [Ep = 1.9 to 155 MeV] see (1975AJ02, 1980AJ01).
At Epol. 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.).
Reported neutron groups are displayed in Table 12.13 (in PDF or PS). Angular distributions have been studied in the range 0.5 < Ed < 11.8 MeV: [see (1968AJ02, 1975AJ02)] and at Ed = 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 < Ed < 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).
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 Ex ≈ 18.4 and ≈ 19.5 are strongly populated (1979SHZH, 1980SH1A).
Angular distributions (reaction (a)) have been studied at several energies in the range Eα = 15.1 to 120 MeV [see (1980AJ01)] as well as at Eα = 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 Ex = 18.35 ± 0.05 MeV (Γ = 350 ± 50 keV) consists of unresolved states with Jπ = 3- (T = 1) and 2- (T = 0 + some mixing of T = 1) (1983NE11; see for spectroscopic factors): no states were observed with Ex > 18.35 MeV.
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.).
The decay is mainly to 12Cg.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) [Jπ = 0+] is of particular interest for helium burning processes in stars: Γrad = 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.).
The total absorption, mainly (γ, n) + (γ, p), is dominated by the giant resonance peak at 23.2 MeV, Γ = 3.2 MeV [σmax = 21 mb (1975AH06)] and by a smaller structure at 25.6 MeV, Γ ≈ 2 MeV [σmax ≈ 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 (σmax ≈ 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 < Ex < 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 1p3/2 → 1d5/2 E1 single-particle character. No significant E2 strength is observed: see (1980AJ01) and (1980GO13; Eγ = 60 MeV).
The cross section for reaction (b) has been measured for Eγ = 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 Eγ = 20 to 140 MeV. Reaction (b) has been studied for Ebs = 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.).
The photoproduction cross section exhibits two broad peaks, the giant resonance peak at 22.5 MeV, Γ = 3.2 MeV, σmax = 13.1 ± 0.8 mb and a 2 MeV broad peak at 25.2 MeV, σmax = 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 Ebs = 21.7 to 42 MeV: most of the transitions are to 11Bg.s. and the excited-state transitions appear to orginate from localized Ex regions (1970ME17, 1980IS1F). For (γ, pX) momentum spectra using tagged photons, see (1983HO01; Eγ = 357 to 557 MeV) and (1984BA09; Eγ = 360 to 600 MeV). See also (1982BA32, 1983DO09), 11B and (1980AJ01).
The photoproduction of neutral pions (reaction (b)) has been studied at Ebs = 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 Eγ = 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.
See also (1979EG02, 1980KI1E, 1981AK1A, 1981AL18, 1981AL1L, 1981AV01, 1981TA1T, 1983ST1G), (1979DE2A, 1979MA1G, 1980GO13, 1981SC1G, 1982DE1H, 1982IN1A), (1982SC1E; astrophys.) and (1978EP01, 1980DU21, 1980MO1M, 1980NA1B, 1980RA05, 1981BO14, 1981RA16, 1982DU1A, 1982GL04, 1982GO01, 1982LO08, 1983CA22, 1983OR03, 1983YU1A, 1984ST1F; theor.).
Cross sections and angular distributions of the deuterons corresponding to transitions to 10Bg.s. and/or low excited states have been measured at Eγ ≈ 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 Ebs = 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 Eγ = 35 to 50 MeV: see (1980AJ01).
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 Eγ < 22 MeV, transitions are mainly to 8Beg.s. and 8Be*(2.9) with the g.s. transition dominating for Eγ ≲ 14 MeV. For Eγ > 26.4 MeV, 8Be (T = 1) levels near 17 MeV are strongly excited. Alpha energy distributions show surprisingly strong E1 contributions below Eγ ≈ 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 Eγ ≈ 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).
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 Eγ = 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; Eγ = 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. Γ4.4/Γ0 at 23.5 MeV = 0.23 ± 0.07 (1983DO05). The scattering cross section has been measured for Eγ = 150 to 400 MeV by (1984HA08). For pair-production measurements at Ebs = 4.2 to 31.1 MeV see (1983NO06). See also (1980HA1W) and (1981KE16, 1981KO1F; theor.).
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 Jπ = 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, Jπ = 2-: see (1975AJ02, 1980AJ01) for references and additional information. At Ee = 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 Ex (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.
See also (1977CR02, 1979HA14, 1979HU1C, 1981CA05, 1981LO02, 1982BU1E, 1982PAZT, 1983BU20, 1983NIZX, 1983PA1D), (1979CA1E, 1979FR1J, 1979PE1F, 1980CA1H, 1980DR1B, 1980SI1B, 1981CA1D, 1981HA1T, 1981SI1B, 1982BE1J, 1982DE1H, 1982DE1J, 1982MO1X, 1983BE1A, 1983HE1E, 1983SI11, 1984OC1B) and (1978HA43, 1979AR1F, 1979BE1G, 1979BU1A, 1979GL10, 1979IN05, 1979KI1G, 1979UE03, 1979WA1G, 1980BA2E, 1980BE58, 1980CH11, 1980DE14, 1980ER1B, 1980HA18, 1980KO1W, 1980PE05, 1980TO04, 1981AM08, 1981BA2T, 1981BU04, 1981DE1T, 1981DE1U, 1981DU16, 1981FI05, 1981KA03, 1981KL1B, 1981KO41, 1981LA1E, 1981LI1X, 1981SI09, 1981SP1A, 1981SU03, 1981SU04, 1981SU08, 1981TO04, 1981VA08, 1981WE1G, 1982BA37, 1982CE03, 1982GU09, 1982IN03, 1982KO21, 1982LE1M, 1982MA38, 1982OS1C, 1982WE1J, 1983BO26, 1983KO32, 1983OC01, 1983PO03, 1984CO1U, 1984DE02, 1984FI06, 1984RO05, 1984ST03; theor.).
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 Ee = 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 Ee = 497 MeV the population of 11B*(0, 2.14, 5.0) is reported: see (1980AJ01) for references. At Ee = 500 MeV momentum distributions for the transition to 11Bg.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 Ee = 86 and 126 MeV (see 11B): the results indicate that more than one Jπ = 1- doorway state is important in the 12C giant resonance.
The π-/π+ ratios have been measured at Eπ = 10 MeV (1979JE04), 15.8 and 17.9 MeV (1982LO07; Ee = 200 MeV). Pion production has also been studied by (1981SE05, 1983SC11): see 12B and 12N. See also (1980AJ01) and the "GENERAL" section here.
See also (1978DE32, 1980GA29, 1982LI1C, 1984LOZY), (1979CA1E, 1979MA1G, 1979MO1G, 1980MO1C, 1980SI1B, 1981HA1T, 1981HU1E, 1981MO1H, 1982DE1W, 1983MO1F) and (1979BE67, 1979KU25, 1980BA2E, 1980BO08, 1980GI1D, 1980HO26, 1980NA13, 1980RO17, 1980SA1E, 1981BO1M, 1981DE07, 1981DE1Q, 1981EI01, 1981KL1A, 1981KL1C, 1981RO1N, 1981TO1N, 1982AL12, 1982CI1D, 1982LO1B, 1982ZI1A, 1983AN1C, 1983BE29, 1983CO18, 1983KL04, 1983NA07, 1984CO07, 1984KL04; theor.).
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 Eπ+ = 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 Eπ+ = 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 Eπ± = 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 Eπ± = 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; Eπ± = 180 and 291 MeV). However (1983LE12) have studied inclusive pion scattering at Eπ+ = 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 Eπ± = 100, 160 and 220 MeV (1981MC09). The cross section for absorption of pions in 12C has been obtained at Eπ± = 50, 85 to 315 MeV and Eπ- = 125 and 165 MeV. A strong energy dependence is observed in the π+ absorption (1981AS07, 1983NA18). At Eπ± = 50 MeV the absorption of π- is about twice that of π+ (1983NA18).
(1981PI05, 1982PI03, 1982PI04) have studied reaction (b) at Eπ+ = 165 MeV and Eπ± = 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.
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); En = 20.7 to 26 MeV) and (1979DEZK; n0; 30.3, 40 MeV). Angular correlations (n1, γ4.4) have been studied at En = 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 En = 11 to 35 MeV see (1983AN02): the sequential decay via 12C*(9.64) and 8Beg.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.).
Angular distributions of elastically and inelastically scattered protons have been measured at many energies up to Ep = 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; Ep = 122 MeV). The angular distributions of the inelastically scattered protons to 12C*(12.71) are usually poorly fitted: see e.g. (1983BA57).
At Ep = 402 MeV the differential cross sections for 12C*(12.7, 15.1) (Jπ = 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 Ep = 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 Epol. p = 24.1, 26.2, 28.7 MeV (1981FU12; to 12C*(4.4)), at Ep = 42 MeV (1981CO08; to 12C*(12.7)), at Epol. 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 Ep = 398, 597 and 698 MeV (1983JO08; to 12C*(18.3, 19.4)). At Epol. 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 Ep = 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 12Cg.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 (Ex ≈ 300 MeV) is reported by (1984MC04: Ep = 800 MeV). See also (1984SEZZ). For spallation see (1979KO21; Ep = 640 MeV) and (1983AN13; Ep = 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; Ep = 22 MeV).
See also (1980PI1A, 1981BR1L, 1981JOZZ, 1981MOZW, 1981SA1T, 1982GU03, 1983CE1A, 1983KA2C), (1978AL36, 1979DE1P, 1979GL1H, 1980CA1H, 1980DE33, 1980DE1V, 1980KE14, 1980MO01, 1980WH1A, 1981BA1F, 1982IG2A, 1982MO1F, 1982WA1H, 1982WE1J, 1983HA1H, 1983MO1K, 1983SC1G), (1979RA1C, 1982RA1M; astrophys.) and (1978CH28, 1979AB13, 1979FO18, 1979MA48, 1979PH05, 1979YU02, 1980AB02, 1980AL12, 1980BA2E, 1980CO07, 1980CO06, 1980CR01, 1980JA05, 1980KO1V, 1980MA06, 1980TO04, 1980WU02, 1981AB1D, 1981BE1Y, 1981BL1C, 1981DY1D, 1981GA1G, 1981GA1J, 1981KA04, 1981KH07, 1981LO11, 1981NO13, 1981PE06, 1981PO1E, 1981TO04, 1981VA1L, 1981WA20, 1981WE1G, 1981YA08, 1982BIZZ, 1982BL22, 1982CH15, 1982DY02, 1982FA03, 1982FI1L, 1982HE1E, 1982MO18, 1982MO24, 1982NA13, 1982OL1C, 1982OS1C, 1982VOZZ, 1982YE01, 1983BA25, 1983DI1B, 1983DI09, 1983FA04, 1983LI1N, 1983NE1F, 1983PH1A, 1983PI1C, 1983TZ01, 1983WA10, 1983ZA1E, 1984BE01, 1984GO04, 1984HW1A, 1984PEZV, 1984PI05, 1984RI03; theor.).
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.).
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 Ep = 670 MeV the missing energy spectrum in the (p, pd) reaction (reaction (c)) shows a strong bump at Emiss. = 25 MeV and another weaker one at Emiss. = 45 MeV corresponding, respectively, to the 10B ground-state region and 10B*(20) (1981ER10).
At Ep = 56.5 MeV reaction (d) proceeds primarily by sequential α-decay. 12C*(22.2 ± 0.5, 26.3 ± 0.5) which subsequently decay to 8Beg.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 Ep = 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.).
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) [Ex = 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 Ed = 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.).
Angular distributions of elastically scattered tritons have been determined at Et = 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.).
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 Ex = 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.).
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, γ4.4) have been carried out for Eα = 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 Eα = 104 MeV, the sum of the E2 strength in the dominant decay channels [α0 + α1 + p0] for 20 < Ex < 30 MeV exhausts less than 15% of the EWSR (1978RI03). At Eα = 150 MeV, the observed isoscalar E2 strength is (6 ± 2)% of the EWSR (1976KN05).
At Eα = 104 MeV (1981EY02) report no evidence for E0 strength in the region of a state at Ex = 9.15 MeV (1980LE25) reported in reaction 45. There is no evidence for concentrated E0 strength above Ex = 7.7 MeV (1981EY02). See also (1981YO04).
Reaction (b) has been studied for Eα up to 700 MeV [see (1975AJ02)] and at Eα = 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 Eα = 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.).
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.).
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.).
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.).
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).
See also (1979SA29, 1980TA1B, 1981PL1C, 1983DA10, 1983ME1Q, 1983SH1Z, 1984HA1U), (1980HE1F, 1982SA1A, 1984FO1A; astrophys.), (1978ER1B, 1978HO1C, 1979CO1F, 1979DE1P, 1979GO1C, 1979SC1D, 1980DE1Z, 1980ER1D, 1980SI1A, 1981BA21, 1981BR1M, 1981BR1P, 1981ER02, 1981SC1N, 1981SC1P, 1981ST1P, 1982CO1X, 1982ER1F, 1982EV1B, 1982FR1G, 1982FR1T, 1982KO1C, 1982MO1N, 1983BI13, 1983BO1M, 1983BR31, 1983GR1M, 1983JA13, 1983NA1K) and (1978AB1A, 1978BH1B, 1978BR1D, 1978DZ1A, 1978FI1D, 1978KO1E, 1978WI05, 1979CU03, 1979DA1F, 1979FR11, 1979HA42, 1979KN03, 1979MO1J, 1979SA1E, 1979SC1F, 1979VA15, 1979YA12, 1980AB1D, 1980BE01, 1980CE1C, 1980CU1D, 1980DR08, 1980FA1D, 1980FL02, 1980FO1D, 1980FU1H, 1980GA1E, 1980HE1F, 1980HE01, 1980KO27, 1980LA09, 1980LA10, 1980LE01, 1980MU02, 1980OH05, 1980SC1D, 1980SI1J, 1980TA01, 1980VA1G, 1980WO01, 1981AB1A, 1981AS1F, 1981BR01, 1981CA09, 1981CH23, 1981CH26, 1981CU03, 1981DA1E, 1981DA1F, 1981DA12, 1981DEZG, 1981DY02, 1981FA1D, 1981FU1F, 1981GA1E, 1981GI10, 1981HA18, 1981HA47, 1981HAZZ, 1981HE01, 1981HE02, 1981HE13, 1981IC01, 1981JE1B, 1981LE20, 1981MA1G, 1981PI1D, 1981SC05, 1981SI1F, 1981SU1J, 1981TA20, 1981UB01, 1981XU1A, 1981YA1D, 1982AB1F, 1982AH02, 1982AH03, 1982BA22, 1982BA37, 1982DE19, 1982HA1R, 1982HA1W, 1982HA56, 1982KO01, 1982KO09, 1982LE09, 1982LE1W, 1982LO13, 1982MA1J, 1982MO1U, 1982MO1V, 1982OH01, 1982SU06, 1982TA13, 1982VO04, 1982WO02, 1983BI01, 1983BI12, 1983BR01, 1983BU15, 1983CH1L, 1983CH38, 1983CI08, 1983CI09, 1983CS01, 1983DE1U, 1983DU13, 1983FA12, 1983FA08, 1983FA14, 1983FO1E, 1983GO25, 1983GU1A, 1983GY1A, 1983HA1E, 1983KA1N, 1983KA1V, 1983KH02, 1983LA09, 1983LA14, 1983MA29, 1983MA1U, 1983SA1D, 1983SM1B, 1983TA01, 1983TA1J, 1983TA13, 1983TA15, 1983TO11, 1984AI01, 1984BA26, 1984CH04, 1984FA02, 1984HU01, 1984LA08, 1984MC06, 1984NY02, 1984OR1B, 1984SH02, 1984TO03; theor.).
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.).
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.).
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 Ec.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).
See also (1979SA1L, 1979UZ1A, 1980CO08, 1981CO1W, 1983AZ1A), (1977GA1B, 1978GA1B, 1979GA1F, 1979GO1C, 1980ER1D, 1980GA1E, 1980GA1J, 1980VO1D, 1981BR1P, 1981GA1D, 1981ST1P, 1982EV1B, 1982FR1T, 1982KO1C, 1982LE1N, 1982MA2B, 1983BI13, 1983BR1R, 1983DU13, 1983HE1B) and (1978BH1B, 1978MA1G, 1979GO24, 1979TE1A, 1979VE1C, 1980AB1D, 1980DE2A, 1980DR08, 1980FU1F, 1980HU02, 1980KO27, 1980LA16, 1980TA1E, 1980TA1G, 1980VA03, 1981CA09, 1981DY02, 1981GU1B, 1981HA18, 1981HU1D, 1981HU07, 1981SC05, 1981TA01, 1981TO1F, 1981UB01, 1981WI01, 1982AB1F, 1982BA22, 1982BR1T, 1982FL1B, 1982GE1B, 1982HA42, 1982HA56, 1982HU1G, 1982KA35, 1982LO13, 1982ME12, 1983AD1E, 1983AU04, 1983BU15, 1983CI08, 1983CI09, 1983DE1U, 1983DE21, 1983DE1Y, 1983DE2G, 1983FR23, 1983KA30, 1983LI1L, 1983MA29, 1983SM1B, 1983TA07, 1984BA26, 1984KA1T; theor.)
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.).
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.).
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.).
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.).
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.).
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.).
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.).
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.).
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): δg.s. = +0.129 ± 0.008 (1978AL01), δ4.4 = -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.).
The decay of the giant resonance in 13C takes place predominantly to 12C*(15.1, 16.1) [and to their analogues in 12B]. Below Eγ = 21 MeV transitions to 12C*(4.4) are dominant: see (1980AJ01). See also (1979WO06, 1980HO11, 1983ZU02) and 13C in (1981AJ01, 1986AJ01).
Angular distributions have been measured at Eπ+ = 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 Eπ+ = 32 MeV are also reported (1982DO01; g.s., 4.4). See also (1982HO1C, 1982LO1B).
Angular distributions have been measured at Ep = 8 to 54.9 MeV [see (1980AJ01)] and at Epol. 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 Ep = 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 Ep = 62 MeV the excitation of states with Ex = 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 Γc.m., in keV]; ln = 1 for all states except 12C*(21.5) and (22.55) for which ln = (1) and ≠ 1, respectively: see (1980AJ01) for references.
At Ep = 800 MeV an enhancement is observed in the yield of forward emitted deuterons (reaction (b)) which correspond to an Ex 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.).
Angular distributions have been studied at Ed = 0.41 to 27.5 MeV [see (1975AJ02, 1980AJ01)] and at Ed-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.).
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 Eα = 24 and 25.5 MeV: the average ratio between the p1/2 and p3/2 amplitudes is -0.086 ± 0.030 (1980BA1U; prelim.). For the earlier work see (1980AJ01).
A study of reaction (b) leads to Γα/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 Γα = 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).
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).
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.).
Angular distributions have been measured at Ep = 14.5, 18.5 and 39.8 MeV: see (1975AJ02). At Ep = 54 MeV angular distributions are reported to two states at Ex = 27.57 ± 0.03 and 29.63 ± 0.05 MeV [Γc.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 Jπ = 0+.] It is not excluded that the group to 12C*(29.63) may be due to unresolved states (1976AS01). (1976AS01) report Γp/Γ ≈ 0.3 ± 0.1 and Γα1/Γ < 0.1 for the first T = 2 state and Γp/Γ = 0.8 ± 0.2, Γp0/Γ ≈ 0.4 and Γα/Γ ≈ 0.2 for 12C*(29.63). (1978RO08) report Ex = 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).
Angular distributions to the ground states have been measured at E(16O) = 20, 25, 30 and 32 MeV: see (1980AJ01).
Angular distributions have been studied at Ep = 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.).
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 Jπ = (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).
Angular distributions of α0 and α1 have been measured for Ep 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) [Jπ = 4+ and 2+]. See also (1983LE25), (1983SC43; applied), (1980CA28; theor.) and 16O in (1982AJ01, 1986AJ04).
At Eα = 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).
See (1984GL1H; theor.).
At Ee = 128 MeV the α-decay is primarily to 12C*(0, 4.4) (1983VOZX).
This reaction appears to proceed primarily via excited states of 13N and 16O to 12C*(4.4) [Ep = 46.8 and 50 MeV]: see (1980AJ01). The reaction has also been studied at Ep = 101.5 MeV (1981CA02; Sα relative to the (p, pα) reaction on other nuclei).
Angular distributions have been measured at Ed = 12.7 to 35 MeV [see (1980AJ01)], at Ed = 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 Sα = 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).
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 Sα] [see (1980AJ01)], as well as at 41 MeV [see (1981LE01)].
At Eα = 90 MeV angular distributions involving 12C*(0, 4.4) (reaction (a)) have been analyzed by PWIA and DWBA by (1976SH02): Sα = 2.9 ± 0.5 and 0.70 ± 0.23, respectively. At Eα = 65 MeV angular distributions involving 8Beg.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 Eα = 55 to 72.5 MeV]: Sα = 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.).
See (1984GO1H; Ed = 13.6 MeV).
Angular distributions have been reported at Eα = 22.8 to 25.4 MeV and at 90 MeV: see (1980AJ01).