Core excitation effects in pion double charge exchange

Technical Report · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5209474

Kaletka, M O

We have measured 5/sup 0/ cross sections for the pion double charge exchange reactions /sup 42/Ca(..pi../sup +/,..pi../sup -/)/sup 42/Ti, /sup 48/Ca(..pi../sup +/,..pi../sup -/)/sup 48/Ti, and /sup 48/Ti(..pi../sup +/,..pi../sup -/)/sup 48/Cr at incident pion energies of 130, 180, 235, and 292 MeV, using the EPICS pion spectrometer facility of the Los Alamos Meson Physics Facility. Excitation functions are presented for the ..delta..T=0 double-isobaric analog transitions to /sup 42/Ti(G.S.), /sup 48/Ti(17.379 MeV), and /sup 48/Cr(8.75 MeV), as well as for the ..delta..T=-2 non-analog transitions to /sup 48/Ti(G.S.) and /sup 48/Cr(G.S.). The shapes of the excitation functions for analog and non-analog transitions are found to be similar to previous measurements on light nuclei. We compare the measured forward-angle cross sections for analog transitions to simple diffractive model calculations which predict a dependence for double charge exchange cross sections proportional to (N-Z)(N-Z-1)/(A/sup 10/3/). While the /sup 48/Ca and /sup 48/Ti cross sections are found to agree well with this proportionality at both 180 and 292 MeV, in both cases the /sup 42/Ca cross sections are found to be anomalously high when compared with other existing data. We attempt to interpret the data using theoretical models in which second-order terms are introduced in the optical model potential. It is found that the data can not be understood in the framework of theories which do not include detailed nuclear structure. However, using a model in which both the second-order optical potential and nuclear structure details are included results in a separation of nuclear structure and reaction mechanism effects. Core excitation components are found to be particularly important in understanding the details of the /sup 42/Ca excitation functions. Extensive list of references.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5209474
• Report Number(s): LA-9947-T; ON: DE84007990
• Country of Publication: United States
• Language: English

Related Subjects

651515 -- Nuclear Properties & Reactions
A=39-58
Theoretical-- Nuclear Reactions & Scattering-- (-1987)
651525* -- Nuclear Properties & Reactions
A=39-58
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BOSONS
CALCIUM 42 TARGET
CALCIUM 48 TARGET
CHARGE-EXCHANGE REACTIONS
CHARGED-PARTICLE REACTIONS
CORRELATIONS
CROSS SECTIONS
DATA
DISTRIBUTION
ELEMENTARY PARTICLES
ENERGY RANGE
EXCITATION FUNCTIONS
EXPERIMENTAL DATA
FUNCTIONS
HADRON REACTIONS
HADRONS
INFORMATION
MESON REACTIONS
MESONS
MEV RANGE
MEV RANGE 100-1000
NUCLEAR REACTIONS
NUMERICAL DATA
OPTICAL MODELS
PION PLUS REACTIONS
PION REACTIONS
PIONS
PIONS MINUS
PSEUDOSCALAR MESONS
TARGETS
THEORETICAL DATA
TITANIUM 48 TARGET