Structure of /sup 13/C studied by pion scattering near the (3,3) resonance

Technical Report · Tue Sep 01 04:00:00 EDT 1981

DOI:https://doi.org/10.2172/5972724· OSTI ID:5972724

Seestrom-Morris, S J

Good resolution (..pi../sup +/,..pi../sup +/') and (..pi../sup -/,..pi../sup -/') data were obtained for many states in /sup 13/C using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility. Differential cross sections were measured for angles between 20/sup 0/ and 105/sup 0/ at an incident pion energy of 162 MeV for the elastic scattering as well as for states at excitation energies of 3.09, 3.68, 3.85, 7.55, 8.86, 9.5, 11.82, 16.05, 17.92, 21.37, and 21.6 MeV. Excitation functions were measured at momentum transfers of q = 1.1 h fm /sup -1/ and q = 1.4 h fm/sup -1/, for energies between 100 and 300 MeV. A sigma(..pi../sup -/)/sigma(..pi../sup +/) ratio of 9:1 was observed for the first time, indicating a pure neutron particle-hole excitation of a high spin state (J/sup ..pi../ = 9/2/sup +/). Strikingly different energy dependences were found for ..delta..S = 0 and ..delta..S = 1 transitions. Data for all states were compared with the microscopic model calculations of Lee and Kurath. Very good agreement was found between experiment and theory for the strongly excited states and the 9/2/sup +/ state at 9.5 MeV, in sharp contrast to the disagreement for weak transitions. The excitation function data and comparisons with the microscopic model calculations were used to identify the states at 16.05, 17.92, 21.37, and 21.6 MeV as either 7/2/sup +/ or 9/2/sup +/ states. The elastic scattering data were analyzed with an optical modeland the results were found to be consistent with neutron and proton distributions having equal rms radii. The optical potentials generated were used in a collective model analysis of the 3/2/sup -/ (3.68 MeV) and 5/2/sup -/ (7.55 MeV) states. The reduced transition probabilities (B(E2)) derived from the proton parts of the transition strength are in agreement with those determined from electromagnetic measurements.

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5972724
• Report Number(s): LA-8916-T; ON: DE82002991
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CARBON 13
CARBON 13 TARGET
CARBON ISOTOPES
CHARGED-PARTICLE REACTIONS
COLLECTIVE MODEL
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
E2-TRANSITIONS
ELASTIC SCATTERING
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
EXCITATION FUNCTIONS
EXPERIMENTAL DATA
FUNCTIONS
HADRON REACTIONS
HIGH SPIN STATES
INELASTIC SCATTERING
INFORMATION
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL MODELS
MESON REACTIONS
MEV RANGE
MEV RANGE 100-1000
MULTIPOLE TRANSITIONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
PION MINUS REACTIONS
PION PLUS REACTIONS
PION REACTIONS
SCATTERING
STABLE ISOTOPES
STRENGTH FUNCTIONS
TARGETS