Kinematically complete measurement of proton knockout by 220-MeV pions on /sup 12/C

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

OSTI ID:5209611

Faucett, J A

The nuclear reaction whereby an incident pion interacts with a nucleus, knocks out a single nucleon, and leaves the nucleus was studied. The experiment was performed with 220 MeV positive and negative pion beams incident on a natural carbon target. The final pion momentum and direction of travel were measured with a magnetic spectrometer. The ejected protons' momenta were measured with a scintillator array. Measurements were taken at scattered pion angles of 61/sup 0/, 81/sup 0/, 105/sup 0/, and 127/sup 0/ for incident positive pions and at 81/sup 0/ for incident negative pions. The protons were observed at angles over the range from 15/sup 0/ to 90/sup 0/. The final particles were observed both separately and in coincidence. The excitation of the residual nucleus was calculated for the coincidence events. Differential cross sections were obtained and displayed as pion and proton energy spectra and as angular correlations. Ratios between the positive and negative pion data were made to elucidate the differences and common features of the two reactions. The data provides detailed evidence for the quasielastic picture of pion knockout reactions which is reflected in the similarity of the spectral peak energies to those seen in pion-nucleon elastic scattering. The importance of secondary processes such as pion multiple scattering and nucleon final state interactions becomes clearer with the separation of the data according to the residual nucleus excitation energy. The coincidence cross section is found to account for about half of the (..pi../sup +/,..pi../sup +/') reaction and about half of this corresponds to quasifree knockout of the outer shell protons. For the (..pi../sup -/,..pi../sup -/'p) reaction, the secondary processes are found to play a much more important role. The data will be valuable for future comparison with theoretical calculations.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5209611
• Report Number(s): LA-9970-T; ON: DE84008366
• Country of Publication: United States
• Language: English

Related Subjects

651325* -- Nuclear Properties & Reactions
A=6-19
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BARYONS
CARBON 12 TARGET
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
DIRECT REACTIONS
DISTRIBUTION
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
EXPERIMENTAL DATA
FERMIONS
HADRON REACTIONS
HADRONS
INFORMATION
KNOCK-OUT REACTIONS
MASS
MESON REACTIONS
MEV RANGE
MEV RANGE 100-1000
MISSING MASS
NUCLEAR REACTIONS
NUCLEONS
NUMERICAL DATA
PION REACTIONS
PROTON SPECTRA
PROTONS
QUASI-ELASTIC SCATTERING
QUASI-FREE REACTIONS
SCATTERING
SPECTRA
TARGETS