Low-energy pion double charge exchange and nucleon-nucleon correlations in nuclei

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6693654

Leitch, M J

Recent measurements of pion double-charge exchange (DCX) at energies 20 to 70 MeV are providing a new means for studying nucleon-nucleon correlations in nuclei. At these energies the nucleus is relatively transparent, allowing simpler theoretical models to be used in interpreting the data and leading to a clearer picture. Also the contribution to DCX of sequential charge-exchange scattering through the intermediate analog state is suppressed near 50 MeV and transitions through non-analog intermediate states become very important. Recent theoretical studies by several groups have shown that while transitions through the analog route involve relatively long nucleon-nucleon distances, those through non-analog intermediate states obtain nearly half their strength from nucleon pairs with less than 1 fermi separation. Thus DCX near 50 MeV is an excellent way to study short-range nucleon-nucleon correlations. Data has been obtained for double-isobaric analog state (DIAS) transitions on /sup 14/C, /sup 18/O, /sup 26/Mg, and a number of nuclei in the f-7/2 shell including /sup 42,44,48/Ca, primarily at 35 and 50 MeV. Additional data for non-analog (ground state) transitions has also been obtained for /sup 12/C. These data are consistent with the two-amplitude theoretical models where the two amplitudes represent scattering through analog and through non-analog intermediate states. Calculations based on shell-model correlations explain the general trends of the data. Preliminary new data on the forward-angle energy dependence of the DIAS and g.s. transitions for /sup 42,44,48/Ca from 25 to 70 MeV is presented here and the current theoretical picture based upon this data is reviewed. 26 refs., 31 figs., 4 tabs.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6693654
• Report Number(s): LA-UR-88-3854; CONF-8810235-1; ON: DE89003492
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BARYON-BARYON INTERACTIONS
CALCIUM 42 TARGET
CALCIUM 44 TARGET
CALCIUM 48 TARGET
CARBON 14 TARGET
CHARGE EXCHANGE
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DISTRIBUTION
ENERGY DEPENDENCE
ENERGY LEVELS
F STATES
HADRON REACTIONS
HADRON-HADRON INTERACTIONS
INTERACTIONS
MESON REACTIONS
NITROGEN 15 TARGET
NUCLEAR REACTIONS
NUCLEI
NUCLEON-NUCLEON INTERACTIONS
PARTICLE INTERACTIONS
PION PLUS REACTIONS
PION REACTIONS
TARGETS