
^{12}C (1985AJ01)(See Energy Level Diagrams for ^{12}C) GENERAL: See also (1980AJ01) and Table 12.6 [Table of Energy Levels] (in PDF or PS). Shell model: (1977ME05, 1978RA1B, 1979HA59, 1979IN05, 1980CA12, 1980GI05, 1980HA35, 1980OH07, 1981AM08, 1981BO1Y, 1981DE2G, 1981LU1B, 1981RA06, 1982AR03, 1982BA52, 1982BR08, 1983VA31, 1984DE04, 1984VA06). Deformed models: (1979UE03, 1980BA1T, 1980BA44, 1980CA12, 1980FU1H, 1981DE2G, 1981RA06, 1981SE03, 1982AS03, 1982BR08, 1982KU1K, 1982SA1U, 1983LO04, 1983SA12, 1983SC08). 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). Applied work: (1977MA1F, 1979AL1P, 1979KU20, 1979SW1C, 1980HE1E, 1980LA1K, 1980PU1A, 1980SE1E, 1981FR1D, 1981SC1D, 1982FR1L, 1983AM1A, 1983GI1E, 1983GO2D, 1983OS1G, 1983SK1B). Complex reactions involving ^{12}C: (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). Antiproton and antineutron reactions (See also reaction 41.): (1978GR1D, 1981AI01, 1981YA1C, 1982IL1A, 1982IL1B, 1982ZH1G, 1983MO1K, 1983NI07, 1983SU04, 1984CO1M, 1984MA17, 1984WO01). 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). Groundstate properties of ^{12}C: (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 ^{12}C*(4.4), Q_{2+} = 6 ± 3 e · fm^{2}, 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 ^{12}C at 30.3 MeV. Cross sections for reaction (e) and the (^{6}Li, ^{5}He) reaction have been measured by (1977RU1A, 1979RU07) for E(^{6}Li) = 2.3 to 15 MeV. (1983WA09) have studied the 3α and 2α + 2d reactions (reactions (g) and (h)) at E(^{6}Li) = 97.5 MeV. The singlespectator 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 ^{8}Be in (1984AJ01). See also (1981NO06, 1981NOZW) and (1983KA1G, 1983KAZF).
Broad structures are reported in the excitation functions for reaction (b) at E(^{6}Li) ≈ 13 and ≈ 26 MeV. Total reaction cross sections for the elastic scattering have been measured at E(^{6}Li) = 2.0 to 5.5 MeV (1983NO08). Polarization measurements have been studied at E(pol. ^{6}Li) = 20.0 MeV for the transitions to ^{6}Li*(0, 2.19) (1981AV1B). See also (1980AJ01), ^{6}He and ^{6}Li in (1979AJ01) and (1979DO1J; theor.).
Observed resonances are displayed in Table 12.8 (in PDF or PS). ^{12}C*(28.2) appears to be formed by s and dwave capture. The γ_{0} and γ_{2} transitions to the 0^{+} states ^{12}C*(0, 7.7) are strong and show a similar energy dependence. A strong nonresonant contribution is necessary to account for the γ_{1} yield. The resonance structure reported by (1974SH01) appears to confirm the role of 3p3h configurations for ^{12}C excitations somewhat above the giant resonance region. The γ_{3} yield is relatively unstructured. See also (1983MAZZ) and (1975AJ02).
Excitation functions for neutrons, production cross sections for ^{11}C and polarizations have been measured for E(^{3}He) = 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(^{3}He) ≈ 2 MeV: E_{x} = 27.8 MeV. The total cross section for ^{11}C production shows a broad maximum, σ = 113 mb at E(^{3}He) = 4.3 MeV. In the range E(^{3}He) = 5.7 to 40.7 MeV it decreases monotonically (1981AN16). Excitation functions and angular distributions for protons (reaction (b)) have been measured for E(^{3}He) = 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(^{3}He) = 13.6 MeV. The results are in agreement with earlier measurements of the analyzing power of the ^{11}B(pol. p, ^{3}He) reaction. The equal values for the polarization and the analyzing power are in agreement with the timereversal invariance (1982HA06). This is confirmed by (1984TR03) [E(^{3}He) = 14 MeV]. See also, however, (1981SL03, 1983LE17, 1983RI01, 1984PO02). Polarization measurements are also reported at E(^{3}He) = 13.0 to 14.2 MeV (1983PO13) and E(pol. ^{3}He) = 14 MeV (1983RO22). See also (1983HA1H). For reaction (c) see (1980CO12).
Analyzing powers have been measured at E(pol. ^{3}He) = 33.3 MeV for nine proton groups. The cross section for groundstate tritons (reaction (b)) inceases monotonically for E(^{3}He) = 2.5 to 4.2 MeV and then shows a broad maximum at E(^{3}He) ≈ 4.5 MeV: see (1980AJ01) for references.
The elastic scattering function decreases monotonically for E(^{3}He) = 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(^{3}He) = 19 to 21 MeV. Polarization measurements have been reported at E(^{3}He) = 18, 31.4 and 32.8 MeV: see (1980AJ01) for references, and (1979KA1G).
Excitation functions for the α_{0} group have been reported for E(^{3}He) = 2 to 10 MeV. Analyzing powers have been measured at E(pol. ^{3}He) = 33.3 MeV: see (1980AJ01) for references and additional information. See also ^{8}Be in (1984AJ01).
Neutron groups have been observed to ^{12}C*(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 ^{12}C*(9.63) are strongly populated (1981HAZV). See also (1981HAZW) and (1980JA1G, 1982SA1M; applied).
At E(^{9}Be) = 26 MeV, θ_{lab} = 10°, ^{12}C*(0, 4.4, 7.7, 9.6, 10.8, 11.8) are populated: the strongest transition is to ^{12}C*(9.6) (1975VE10). See also (1981KEZY).
At E(^{9}Be) = 26 MeV, θ = 10°, strong transitions are observed to ^{12}C*(4.4, 7.7, 9.6) (1975VE10). See also (1981BR1H; theor.).
At E(^{3}He) = 13 MeV neutron groups are observed to ^{12}C*(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 ^{12}C (1974GO23).
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 nonresonant yield of 15 MeV γrays is due to a direct capture process or to a very broad resonance: see (1975AJ02).
The thintarget 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 thicktarget yields for 4.3 MeV γrays for E_{d} = 111 to 170 keV; astrophysical Sfactors were also calculated. See aslo (1983SZZY; astrophys.), (1979LE1D; applied) and ^{11}C.
Thicktarget yields have been measured for E_{d} = 91 to 161 keV (1981CE04; also calculated astrophysical Sfactor). 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 ^{11}B.
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 ^{10}B*(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, slowlyvarying structures: see (1980AJ01) [and see for polarization measurements]. See also ^{10}B in (1984AJ01).
Excitation functions have been measured for the α_{0} and α_{1} groups for E_{d} = 0.4 to 12 MeV. Broad maxima in the α_{0} 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 ^{8}Be 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(^{3}He) = 1.4 to 14 MeV: see (1968AJ02) for references. Reactions (b) and (c) have been used to study the α and the pdecay of a number of ^{12}C states. For a study of the matrix element between ^{12}C*(12.7, 15.1) see Table 12.10 (in PDF or PS). See also (1979SHZH, 1983CH08).
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.).
At E(^{6}Li) = 4.9 MeV angular distributions have been obtained for the αparticles to ^{12}C*(0, 4.4, 7.7, 9.6). The population of ^{12}C*(11.8, 12.7) is also reported, as is that of ^{12}C*(15.11) [T = 1]: see (1975AJ02) for references.
For reaction (a) see (1983DA20). Reaction (b) has been studied at energies to E(^{14}N) = 93.6 MeV, involving ^{12}C*(0, 4.4): see (1980AJ01). See also (1983KL1A). Reaction (c) has been investigated at E(^{16}O) = 26 to 32.5 MeV, involving ^{14}N_{g.s.} and ^{12}C*(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 ^{12}C 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(γ_{0}) 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 γ_{1} occurs at E_{p} ≈ 10.3 MeV (E_{x} = 25.4 MeV, Γ_{c.m.} ≈ 6.5 MeV). Absolute crosssection 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 γ_{0} giant resonance. The analysis of γ_{1} 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 γ_{0}, γ_{1}, γ_{2} and γ_{3} [to ^{12}C*(0, 4.4, 7.7, 9.6)] has been studied by (1977SN01): the γ_{2} yield shows a peak at E_{p} ≈ 14.3 MeV with a cross section ≈ 2.3% that of γ_{0} [in γ_{0} yield, E_{res} = 15.0 MeV (1977SN01)] and perhaps as well a lowintensity structure at E_{p} = 11.8 MeV. The γ_{3} 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 γ_{0} and γ_{1} for E_{p} = 18 to 43 MeV. They report giant resonances based on various excited states of ^{12}C at E_{x} = 22.5 and 25.5 MeV (γ_{0}) 25.5, 27.4 and (31) MeV (γ_{1}), 27.4, 31 and (37) MeV (γ_{3}), as well as in the γyield 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 γrays (γ_{19}) to ^{12}C*(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 directcapture model although the analyzing powers are about a factor of two larger than the measured values at back angles (1982WE08) [yield of γ_{19} for E_{p} = 23 to 60 MeV; γ_{0} and γ_{1} yields for E_{p} = 8 to 60 MeV; angular distributions (γ_{0}, γ_{1}) at 14.5, 17.0 and 28.7 MeV]. At E_{pol. p} = 40 and 50 MeV analyzing powers to ^{12}C*(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 α_{0}) and 6 to 24 MeV (1983BU06; α_{0}, α_{1}). 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 ^{8}Be 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 Sfactor and the reaction rate < σν > have been calculated. The values of < σν > obtained in this work suggest that the ^{11}B(p, 3α) reaction may be a poorer candidate for CTR than previously thought (1979DA03). At higher energy the reaction proceeds predominantly by sequential twobody decays via ^{8}Be*(0, 2.9): see ^{8}Be in (1984AJ01). Contributions from ^{12}C*(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 lowlying resonances: for a full list of references see (1968AJ02, 1980AJ01). E_{p} = 0.16 MeV [^{12}C*(16.11)]. This is the J^{π} = 2^{+}; T = 1 analog of the first excited states of ^{12}B and ^{12}N. The γdecay is to ^{12}C*(0, 4.4, 9.6), and also ^{12}C*(12.71) [see Table 12.7 (in PDF or PS)]: the angular distribution of γ_{3}, together with the known αdecay of ^{12}C*(9.6), fix J^{π} = 3^{} for the latter. E_{p} = 0.67 MeV [^{12}C*(16.57)]. The proton width [Γ_{p} ≈ 150 keV] indicates swave protons and therefore J^{π} = 1^{} or 2^{}. This is supported by the near isotropy of the two resonant exit channels, α_{1} and γ_{1}. The α_{1} cross section indicates 2J + 1 ≥ 5: therefore J^{π} = 2^{}, [This is consistent with the results of an αα correlation study via ^{8}Be*(2.9).] The γ_{1} E1 transition has M^{2} ≈ 0.1 W.u., suggesting T = 1. E_{p} = 1.4 MeV [^{12}C*(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 α_{0} and γ_{0} 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 [^{12}C*(17.8)]. The resonance in the yield of α_{0} requires natural parity, the small αwidths suggest T = 1. For J^{π} = 1^{} or 3^{} the small γwidths 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 γray to ^{12}C*(12.71): Γ_{γ} = 3.7 ± 1.5 eV. The angular distribution is isotropic, as expected (1982HA12). E_{p} = 2.37 MeV [^{12}C*(18.13)]. Seen as a resonance in the yield of 15.1 MeV γrays: 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 nonresonant background excludes a definite assignment. E_{p} = 2.62 MeV [^{12}C*(18.38)]. The resonance for α_{0} requires natural parity; the presence of a large P_{4} 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 ^{12}C*(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 ^{12}C*(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 [^{12}C*(18.39)] is not seen here: see ^{11}B(p, p). E_{p} = 3.12 MeV [^{12}C*(18.81)]. The angular distribution of γ_{0} indicates E2 radiation, J^{π} = 2^{+}. This assignment is supported by the angular correlation in the cascade γ_{1} and by the behavior of σ(α_{0}); T = 1 is suggested by the small Γ_{α}. The yield of γ_{3} (to ^{12}C*(9.6)) shows a peak corresponding to E_{x} ≈ 18.9  19.0 MeV. It may be due to ^{12}C*(18.8) with an energy shift due to interference (1982WR01). The structure near E_{p} = 3.5  3.7 MeV [^{12}C*(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(α_{0}) 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(γ_{1}) also appear in σ(α_{1}), but not in σ(α_{0}). Angular distributions suggest J^{π} = 2^{+} or 3^{} for the latter [^{12}C*(20.64)]; the strength of γ_{1} and absence of γ_{0} favors J^{π} = 3^{}, T = 1. The first seven T = 1 states in ^{12}B and ^{12}C 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 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; n_{0} and n_{1} 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.).
Anomalies and maxima observed in the excitation functions of p_{0}, p_{1}, p_{2} and p_{3} 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; p_{0}, p_{1}, p_{2}, p_{3} [and α_{0}: see Table 12.11 (in PDF or PS)]) and 5.4 to 7.0 MeV (1981HO13; p_{0}, p_{1}). 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 lowenergy 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 ^{10}B(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.).
For studies of a possible violation of timereversal invariance see (1981SL03, 1983RI01). See, however, reactions 4 and 23 here and reaction 13 in ^{11}B. See also (1981VI1B, 1983HA1H).
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 ^{13}C in (1986AJ01).
Observed deuteron groups are displayed in Table 12.13 (in PDF or PS). Angular distributions have been studied at E(^{3}He) = 5.1 to 44 MeV: see (1975AJ02, 1980AJ01). At E(^{3}He) = 43.6 MeV the regions with E_{x} ≈ 18.4 and ≈ 19.5 are strongly populated (1979SHZH, 1980SH1A).
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; t_{0}, t_{1}). See also (1979ZE1B, 1980ZE05, 1982BE17, 1983BE1Q, 1984ZE1B; theor.). At E(^{7}Li) = 34 MeV, angular distributions have been measured for the groups to ^{12}C*(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.
Angular distributions (reaction (b)) have been measured at E(^{16}O) = 27 to 60 MeV, involving ^{12}C*(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 ^{12}C_{g.s.}; branching ratios to ^{12}C*(0, 4.4, 7.7, 10.3) are displayed in Table 12.14 (in PDF or PS). All the observed transitions are allowed. The halflife is 20.20 ± 0.02 msec (1978AL01). ^{12}C*(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 ^{12}C*(12.7) has been unsuccessful: see (1968AJ02, 1975AJ02). The shapes of the βspectra of ^{12}B and ^{12}N have been analyzed. The results are in agreement with CVC and with the absence of secondclass 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 [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, n_{0}) cross section has been measured at 90° for 21 < E_{x} < 40 MeV and compared with the (γ, p_{0}) cross section: the isospin mixing averages about 2% in intensity and shows structure at the giant resonance. Angular distributions of n_{0} measured over the giantresonance region indicate that the main excitation mechanism is of a 1p_{3/2} → 1d_{5/2} E1 singleparticle 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.).
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, p_{0}) 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 giantresonance 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 ^{11}B(p, γ_{0})^{12}C [see reaction 21] when the population of ^{11}B*(4.4, 5.0) is taken into account. [See also (1984KE05)]. The fraction of transitions to ^{11}B*(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 ^{11}B_{g.s.} and the excitedstate 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), ^{11}B 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 ^{12}B and ^{12}N. 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 ^{10}B_{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 ^{10}B via nonE2 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).
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 ^{8}Be_{g.s.} and ^{8}Be*(2.9) with the g.s. transition dominating for E_{γ} ≲ 14 MeV. For E_{γ} > 26.4 MeV, ^{8}Be (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 γrays from the decay of ^{7}Be, 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).
Resonance scattering and absorption by ^{12}C*(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 ^{12}C*(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}/Γ_{0} 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 pairproduction measurements at E_{bs} = 4.2 to 31.1 MeV see (1983NO06). See also (1980HA1W) and (1981KE16, 1981KO1F; theor.).
The nuclear charge radius is < r^{2} >^{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 Xrays 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). ^{12}C 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 ^{12}C*(4.4, 7.7, 9.6). Longitudinal form factors show ^{12}C*(16.1, 18.6, 20.0, 21.6, 22.0, 23.8, 25.5) while the transverse form factors show ^{12}C*(15.1, 16.1, 16.6, 18.1, 19.3, 19.6, 20.6, 22.7, (25.5)). ^{12}C*(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). Deepinelastic scattering up to and including the Δregion 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 quasielastic 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 ^{11}B*(0, 2.14, 5.0) is reported: see (1980AJ01) for references. At E_{e} = 500 MeV momentum distributions for the transition to ^{11}B_{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 ^{11}B for E_{e} = 86 and 126 MeV (see ^{11}B): the results indicate that more than one J^{π} = 1^{} doorway state is important in the ^{12}C 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 ^{12}B and ^{12}N. 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 ^{12}C and on ^{11}B at E_{π+} = 38.6 and 47.7 MeV. The difference in the charge radius < r^{2} >^{1/2} is 0.072 ± 0.021 fm for ^{12}C and ^{11}B. See also (1984DU01; theor.). At E_{π+} = 162 MeV π^{+}  γ angular correlations via ^{12}C*(4.4) have been studied by (1984VO04): the results support use of the isobarhole formalism. At E_{π±} = 100 to 130 MeV the chargedependent matrix element between ^{12}C*(12.71, 15.11) has been studied by (1981MO07): see Table 12.10 (in PDF or PS). ^{12}C*(14.1, (15.4), 16.1) are also populated. The possible group to ^{12}C*(15.4) has a width of ≈ 2 MeV (1981MO07). A strong energydependent enhancement in the pion scattering to ^{12}C*(15.1) but not to ^{12}C*(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 singlestep 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 ^{12}C 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.
At E_{K±} = 442 MeV angular distributions have been obtained for ^{12}C*(0, 4.4, 9.6) (1982MA16). See also (1979CH34).
Angular distributions of elastic and inelastically scattered neutrons have been studied at many energies up to 350 MeV: see (1980AJ01) and (1983WO02; n_{0}; 8.9 → 14.9 MeV), (1983DA22; n_{0}; 9.6 → 15 MeV), (1983ANZY; n_{0}, n_{1}; 10 MeV; small angles), (1982HAZK; n_{0}; 14.6 MeV), (1981GU12; n_{0}, n_{1}, n_{2}, n_{3}; 14.7 MeV), (1980TH07; n_{0}, n_{1}; 15.0 → 18.25 MeV), (1979BE50; n_{0}; 16.1 MeV), (1981MEZV, 1982MEZZ, 1983MEZY, 1983MEZS, 1983PEZY; neutrons to ^{12}C*(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; n_{0}; 30.3, 40 MeV). Angular correlations (n_{1}, γ_{4.4}) have been studied at E_{n} = 13.9 to 15 MeV: see (1975AJ02). For discussions of the spinflip probability involving the transition to ^{12}C*(4.4), see (1975AJ02) and (1980TH07). The quadrupole deformation parameter β_{2} = 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 ^{12}C*(9.64) and ^{8}Be_{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.).
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 ^{12}C. 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 tmatrix approximation with densitydependent 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 ^{12}C*(12.71) (S = 1, T = 0) remains a puzzle (1980CO05; E_{p} = 122 MeV). The angular distributions of the inelastically scattered protons to ^{12}C*(12.71) are usually poorly fitted: see e.g. (1983BA57). At E_{p} = 402 MeV the differential cross sections for ^{12}C*(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 spinflip probability (SFP) for the transition to ^{12}C*(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 ^{12}C*(4.4)), at E_{p} = 42 MeV (1981CO08; to ^{12}C*(12.7)), at E_{pol. p} = 397 MeV (1982SE12; to ^{12}C*(9.6, 12.7, 15.1, 16.1)) [the SFP to ^{12}C*(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 ^{12}C*(18.3, 19.4)). At E_{pol. p} = 23 to 27 MeV (1980HO06) have tried to study outofplane (p, p'γ) angular correlations to determine the SF M1 contribution to the cross section for ^{12}C*(12.7, 15.1): the study was not successful. See also (1979PR04). (1980HO07) have measured the angular distribution of γrays from the decay of ^{12}C*(12.7, 15.1) at E_{p} = 21.5 to 27 MeV. Microscopic DW calculations were performed for the A_{0} and a_{2} coefficients from these and earlier data. The theoretical calculations underestimate A_{0} for energies below 35 MeV and are in agreement with the experimental A_{0} for higher energies. The calculations also predict significant differences in the a_{2} values for the transitions from ^{12}C*(12.7, 15.1), and these are observed (1980HO07). β_{2} = 0.663, β_{4} ≈ 0 for ^{12}C_{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 ^{13}N in (1981AJ01, 1986AJ01). A study of inclusive reactions in the region dominated by the Δisobar (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 ^{12}C*(12.7, 15.1) looking for axions (m ≈ 12 MeV): the results were negative. The e^{+}e^{} pair decay of ^{12}C*(15.1) has been observed (1982EN01; E_{p} = 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 ^{12}C*(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 antiprotoncarbon optical potential. There is some evidence for the excitation of ^{12}C*(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 ^{11}B 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 ^{10}B groundstate region and ^{10}B*(20) (1981ER10). At E_{p} = 56.5 MeV reaction (d) proceeds primarily by sequential αdecay. ^{12}C*(22.2 ± 0.5, 26.3 ± 0.5) which subsequently decay to ^{8}Be_{g.s.} must therefore have natural parity and a significant T = 0 admixture. ^{12}C*(19.7, 21.1, 26.3) decay to ^{8}Be*(2.9). These states must also have a T = 0 component. It is suggested that ^{12}C*(21.1) has unnatural parity (1969EP01). In recent work at E_{p} = 44.2 MeV ^{12}C*(12.7, 14.1, 21.6, 26.6) are observed in the angular correlation involving α_{0} and ^{12}C*(21.6, 24.1, 26.6) decay via α_{1} to ^{8}Be*(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 wellknown states in ^{12}C such as ^{12}C*(4.4) [E_{x} = 4440.5 ± 1.1 keV] and ^{12}C*(12.7, 15.1) [see Table 12.10 (in PDF or PS) for chargedependent matrix element], the population of ^{12}C*((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 β_{2} = 0.48 ± 0.02 and 0.47 ± 0.05, and β_{3} = 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 ^{14}N 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 E_{t} = 1.0 to 20.04 MeV: see (1975AJ02) and Table 12.17 (in PDF or PS) here. See also ^{15}N in (1981AJ01) and (1980KH09, 1982GUZS; theor.).
Angular distributions of ^{3}He ions have been measured in the range E(^{3}He) = 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 ^{3}He groups are displayed in Table 12.19 (in PDF or PS). Angular distributions of the ^{3}He groups to ^{12}C*(15.11, 16.11, 16.58, 19.56) have been compared with those for the tritons to ^{12}N*(0, 0.96, 1.19, 4.25) in the analog (^{3}He, 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. ^{12}C*(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 (energyweighted 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(^{3}He) = 33 MeV) and (1980MA07; E(^{3}He) = 90 MeV). See also (1983CA07). See also ^{15}O 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 ^{12}C are displayed in Table 12.19 (in PDF or PS). The quadrupole deformation parameter β_{2} is 0.29 ± 0.02, 0.30 ± 0.02 [see (1980AJ01)], 0.40 ± 0.02 (1983YA01), while β_{3} ≈ 0.23 [see (1980AJ01)] and β_{4} = +0.16 ± 0.03 (1983YA01; see also for a review of deformation parameters). Angular correlation measurements (α_{1}, 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 [α_{0} + α_{1} + p_{0}] 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 crosssection measurements (reaction (a)) of the transitions to ^{12}C*(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 ^{16}O 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(^{6}Li) = 4.5 to 100 MeV [see (1975AJ02, 1980AJ01)] and 20 to 156 MeV [see Table 12.20 (in PDF or PS) here]. At E(^{6}Li) = 36.4 and 40 MeV (1974BI04) have studied the inelastic angular distributions to ^{12}C*(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(^{6}Li) = 60 MeV takes place via ^{12}C*(0, 4.4, 7.7) (1982AR20). See also ^{16}O in (1982AJ01, 1986AJ04). The elastic scattering in reaction (c) has been studied at E(^{7}Li) = 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 ^{18}F, ^{19}F 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(^{9}Be) = 14 to 43.8 MeV, E(^{12}C) = 12 to 21 MeV [see (1980AJ01)] and at E(^{9}Be) = 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(^{10}B) = 18 and 100 MeV. Elastic angular distributions in reaction (b) have been studied at E(^{12}C) = 15 to 87 MeV. See (1980AJ01) and Table 12.20 (in PDF or PS) here. For fusion crosssection and excitationfunction 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(^{12}C) = 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 ^{12}C*(4.4) have been studied by the angular correlation method by (1979CA13, 1981BA21; E(^{12}C) = 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 crosssectionmeasurements, 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(^{12}C) = 15 to 87 MeV and E(^{13}C) = 12 and 36 MeV [see (1975AJ02)] and at E(^{12}C) = 15 MeV [elastic; see (1980VO05)] and E(^{13}C) = 87 MeV (1981TA21; to ^{12}C*(4.4)). Elastic angular distributions in reaction (b) are reported at E(^{12}C) = 12 to 20 MeV: see (1980AJ01). For a study of the spinflip probability to ^{12}C*(4.4) see (1981TA21). See also (1984BYZZ). For fusion, yield and crosssection 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(^{14}N) = 21 to 155 MeV (at certain energies involving ^{12}C*(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(^{15}N) = 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; ^{12}C*(4.4)). The SFP (transition to ^{12}C*(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(^{16}O) = 17.3 to 315 MeV and at E(^{12}C) = 65 to 76.8 MeV [see (1975AJ02, 1980AJ01)] and at E(^{16}O) = 21 to 315 MeV [see Table 12.20 (in PDF or PS)]. The excitation of ^{12}C*(0, 4.4, 14.1, 26) has been reported. (1979DO01) present evidence for the excitation of giant resonances in a number of nuclei including ^{12}C: ^{12}C*(25.3  26.7) (Γ ≈ 4 MeV) contain (25^{+15}_{10})% of the E2 strength. The mstate populations in the transition to ^{12}C*(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 ^{16}O*(6.13) are reported by (1979JA25, 1980JA06). See also (1984PO01) and ^{16}O in (1986AJ04). Reaction (b) has been studied at E(^{16}O) = 25.96 MeV (1983GE09), 140 MeV (1980RA12, 1981RA20) and 142.4 MeV (1983SH26: ^{12}C*(0, 4.4) are involved, as are a number of ^{16}O states. See also (1983KA10, 1984MU04). For fusion, yield and crosssection 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(^{17}O) = 30.5 to 35 MeV and at E(^{18}O) = 32.3 to 57.5 MeV [see (1980AJ01)] and at E(^{18}O) = 32.0 to 140 MeV (1982HE07). For reaction (b) see also (1984BH01) in ^{18}O in (1987AJ02). For fusion, yields and crosssection 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(^{19}F) = 40, 60 and 68.8 MeV [see (1980AJ01)], at 18.0, 20.7, 21.5 and 22.3 MeV (1981MAZJ) and at E(^{12}C) = 30.0, 40.3, 50.0 and 60.1 MeV (1984TA08). See also ^{19}F 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(^{12}C) = 37 MeV and E(^{20}Ne) = 65.7 MeV [see (1980AJ01)] as well as at E(^{12}C) = 20 to 34.4 MeV (1983RI13), 60.7 and 72.6 to 75.2 MeV (1982SH29; also ^{20}Ne*(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 ^{20}Ne in (1983AJ01), (1980CO08, 1980MA1T, 1983OS1J), (1979GO1C, 1981SC1J, 1983BI13, 1983DU13 [also on ^{23}Na], 1983HE1B), (1981RO1W; astrophys.) and (1978VO13, 1980OH05, 1981AB1A, 1981AN1D, 1981VA1E, 1982LO13, 1983CI08, 1983TO1L; theor.).
Elastic angular distributions (reaction (a)) have been measured at E(^{12}C) = 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(^{12}C) = 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(^{12}C) = 30.0 to 39.9 MeV (1979RO11), while that of the transition to ^{12}C*(4.4) has been studied at E(^{12}C) = 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(^{12}C) = 19 to 186.4 MeV and at E(^{28}Si) = 58.3 to 116.7 MeV [see (1980AJ01)] as well as at E(^{12}C) = 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(^{12}C) = 35.8 MeV and E(^{32}S) = 73.3 to 128.3 MeV [see (1980AJ01)] and at E(^{32}S) = 60 to 99 MeV (1982CH02) and 160 MeV (1983GI12). For fusion and yield measurements see (1982CH02, 1983RAZY). See also (1979DE1N, 1982BR1T, 1983DU13 [also on ^{31}P, ^{34}S, ^{35}S, ^{35}Cl, ^{37}Cl, ^{36}Ar, ^{38}Ar], 1983GI12) and (1982BRZE; theor.).
Elastic angular distributions have been studied at E(^{12}C) = 54 and 63 MeV (1980GL03). See also (1983DU13; also on ^{40}K).
The elastic scattering in reactions (a), (b) and (c) has been studied at E(^{12}C) = 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 ^{43}Ca, ^{46}Ca]) 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 ^{12}C are displayed in Table 12.21 (in PDF or PS). The halflife of ^{12}N is 11.000 ± 0.016 msec (1978AL01). See also (1968AJ02). The ratio of the branching ratios ^{12}N/^{12}B for the decays to ^{12}C*(4.4) is 1.607 ± 0.021 (1981KA31). This leads to the following values for the mirror asymmetries of ^{12}B and ^{12}N for decay to ^{12}C*(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 ^{12}B (see reaction 29 and Table 12.14 (in PDF or PS) in ^{12}C) 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 ^{13}C takes place predominantly to ^{12}C*(15.1, 16.1) [and to their analogues in ^{12}B]. Below E_{γ} = 21 MeV transitions to ^{12}C*(4.4) are dominant: see (1980AJ01). See also (1979WO06, 1980HO11, 1983ZU02) and ^{13}C in (1981AJ01, 1986AJ01).
Angular distributions have been measured at E_{π+} = 90 and 170 MeV to ^{12}C*(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 energydependent ratio for the excitation of ^{12}C*(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).
Angular distributions have been measured at E_{p} = 8 to 54.9 MeV [see (1980AJ01)] and at E_{pol. p} = 65 MeV (1980HO18, 1982KA01; ^{12}C*(0, 12.7, 15.1, 16.1); see also for C^{2}S), 200 and 400 MeV (1981LI06; ^{12}C*(0, 4.4)), and at E_{p} = 800 MeV (1980BA02; ^{12}C*(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 ^{14}N 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 ^{12}C*(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 ^{12}C. It is suggested that it may be due to the formation of lowspin (ΔN^{1}) states in ^{12}C (1983MO04). See also (1980CA1A, 1982LO1B, 1982YA1A, 1984PEZW) and (1980BA54, 1980SH1J, 1983DI1C, 1983TO10; theor.).
Angular distributions have been studied at E_{d} = 0.41 to 27.5 MeV [see (1975AJ02, 1980AJ01)] and at E_{dbar} = 29 MeV (1979CO08; to ^{12}C*(0, 4.4, 12.71, 15.11, 16.11) [see also ^{13}C(d, ^{3}He) in ^{12}B]. For chargedependent matrix elements between ^{12}C*(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(^{3}He) = 45 MeV [see (1980AJ01)] as well as at 18.3 and 23.1 MeV (1982GU12; α_{0}, α_{1}). Angular correlations involving ^{12}C*(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 ^{12}C*(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 αwidth is the result of the mixing between ^{12}C*(12.71, 15.11) via a chargedependent 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 ^{16}O in (1982AJ01).
At E(^{7}Li) = 34 MeV angular distributions have been observed for the reactions to ^{12}C*(0, 4.4) + ^{7}Li*(g.s., 0.48) and ^{8}Li*(0, 0.95) in all combinations. While ^{12}C*(0, 4.4) are dominant in the two spectra, ^{12}C*(7.7, 9.6) and, in reaction (a) at E(^{6}Li) = 36 MeV, ^{12}C*(12.7) are also populated (1973SC26).
Angular distributions have been reported at E(^{13}C) = 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.).
Angular distributions for reaction (a) have been measured at E(^{16}O) = 13 to 46.0 MeV: see (1980AJ01). See also (1980RA12) in ^{16}O 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 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 ^{12}B, reached in the (p, ^{3}He) reaction [see reaction 24 in ^{12}B]. The lower T = 2 state is well fitted by L = 0; the angular distribution to ^{12}C*(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 ^{12}C*(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 ^{12}C*(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 ^{8}Be(0) + α; ^{11}B*(0, 2.12, 4.45, 5.02, 6.74 + 6.79) + p; and ^{10}B(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(^{16}O) = 20, 25, 30 and 32 MeV: see (1980AJ01).
See (1980AJ01).
Angular distributions have been studied at E_{p} = 7.5 to 52 MeV [at the higher energies to ^{12}C*(12.7, 14.1, 15.1, 16.1) as well as to ^{12}C*(0, 4.4)]. (1979SHZH; prelim.) conclude on the basis of the results in this reaction and in the ^{14}N(d, α) reaction that ^{12}C*(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 αparticle 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 αparticles to ^{12}C*(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 ^{12}C*(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 ^{16}O in (1982AJ01, 1986AJ04).
See (1978BE1G) and (1980SH04; theor.).
See (1982QU1B).
See (1983KL1A).
See (1979UE01) in reaction 59 of ^{15}N (1981AJ01).
Angular distributions of α_{0} and α_{1} have been measured for E_{p} up to 43.7 MeV: see (1980AJ01). At the highest energy the angular distributions to the 0^{+} states ^{12}C*(0, 7.65, 17.76) are fitted by L = 1, and L = 3 is consistent with distributions to ^{12}C*(14.1, 16.1) [J^{π} = 4^{+} and 2^{+}]. See also (1983LE25), (1983SC43; applied), (1980CA28; theor.) and ^{16}O in (1982AJ01, 1986AJ04).
At E_{α} = 42 MeV angular distributions have been obtained for all four of the transitions involving ^{12}C*(0, 4.4) and ^{7}Li*(0, 0.48): see (1980AJ01).
See (1984GL1H; theor.).
At E_{e} = 128 MeV the αdecay is primarily to ^{12}C*(0, 4.4) (1983VOZX).
This reaction appears to proceed primarily via excited states of ^{13}N and ^{16}O to ^{12}C*(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).
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 ^{12}C*(0, 4.4, 7.7, 9.6, 14.1). See also (1979OE04, 1984NE1A) and (1980AJ01).
Angular distributions have been studied at E(^{3}He) = 30 MeV (^{12}C*(0, 4.4, 7.7, 9.6) and ^{7}Be*(0, 0.4)) and 70 MeV (^{12}C*(0, 4.4) and ^{7}Be*(0, 0.4)) [see for S_{α}] [see (1980AJ01)], as well as at 41 MeV [see (1981LE01)].
At E_{α} = 90 MeV angular distributions involving ^{12}C*(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 ^{8}Be_{g.s.} (reaction (b)) and ^{12}C*(0, 4.4, 7.7, 9.6, 14.1) have been measured by (1976WO11) [the groundstate distributions have also been studied for E_{α} = 55 to 72.5 MeV]: S_{α} = 0.25, 1.07, 0.05, 1.40 for ^{12}C*(0, 4.4, 7.7, 14.1). See also (1980BE04), (1980WE1D), (1983FR14) in ^{16}O (1986AJ04), and (1981BA20; theor.).
For reaction (a) see ^{20}Ne in (1983AJ01). See also (1981PO1A) and (1981KR09; theor.). For reaction (b) see (1982PE08).
At E_{d} = 13.6 MeV angular distributions have been obtained for the ^{9}Be groups to ^{12}C*(0, 4.4) (1981GO16). See (1980AJ01) for the earlier work.
Angular distributions have been measured in the range E_{α} = 13.4 to 20.8 MeV (1981DA13). See also ^{20}Ne in (1987AJ02).
See (1984GO1H; E_{d} = 13.6 MeV).
Angular distributions have been reported at E_{α} = 22.8 to 25.4 MeV and at 90 MeV: see (1980AJ01).
For (a) see (1979CA1E); for (b) see (1980SC1F; theor.).
