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A study of the inclusive inelastic scattering of 100 MeV pions from /sup 2/H, /sup 3/He and /sup 4/He

Technical Report ·
OSTI ID:6566271

Measurements were carried out of the double-differential cross sections of 100 MeV positive and negative pions inelastically scattered from /sup 2/H, /sup 3/He and /sup 4/He. Inclusive spectra and angular distributions of the scattered pions from the (..pi..,..pi..') reaction were obtained at several angles for the three targets using a magnetic spectrometer. The targets considered in the experiment were all gases. The yields of the scattered pions from /sup 2/H, /sup 3/He and /sup 4/He were normalized to measured /sup 1/H scattering data and to the known ..pi../sup +/N cross sections in the literature. The angular distributions of 100 MeV pions scattered from /sup 2/H, /sup 3/He and /sup 4/He at the back angles (theta/sub lab/ greater than or equal to 75/sup 0/) were found to have very nearly the same shape as the free ..pi../sup +/-p distribution at this energy. The ratios of the energy- and angle-integrated ..pi../sup +/ inelastic scattering cross sections at the back angles compared to the free ..pi../sup +/-p cross sections were found to be 0.69 +- 0.03 for /sup 2/H, 1.42 +- 0.06 for /sup 3/He, and 0.88 +- 0.03 for /sup 4/He. The inelastic scattering reaction of pions from /sup 2/H, /sup 3/He and /sup 4/He were interpreted from the point of view that the initial interaction is that of a pion with a single nucleon. Classical and quantum mechanical calculations were carried out to better understand the ..pi..N interaction inside nuclei. It was found that pion interactions with /sup 2/H, /sup 3/He and /sup 4/He at energies below the (3,3) resonance can be viewed effectively in terms of pion interaction with individual nucleons in these nuclei. It was also found that pion absorption cross section in /sup 4/He is unusually large compared to that in other nuclei. Some possible reasons are suggested for this behavior of pions interacting with /sup 4/He. 80 refs., 42 figs., 29 tabs.

Research Organization:
Washington Univ., Seattle (USA). Nuclear Physics Lab.
DOE Contract Number:
AC06-81ER40048
OSTI ID:
6566271
Report Number(s):
DOE/ER/40048-191-L7; ON: DE87007124
Country of Publication:
United States
Language:
English