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Title: (. pi. ,p) reactions at low excitation energy

Journal Article · · Phys. Rev. C; (United States)

Results of the first experimental search for the excitation of discrete final states following exclusive (..pi../sup -/,p) reactions are reported. The measurements include differential cross section at theta/sub lab/ = 25/sup 0/ for (..pi../sup +- /,p) reactions on /sup 24/Mg, /sup 27/Al, /sup 40/Ca, and /sup 58/Ni at T/sub ..pi../ = 120 MeV and (..pi../sup -/,p) on /sup 12/C at T/sub ..pi../ = 145 MeV. The (..pi../sup -/,p) reactions yield peaks with dsigma/d..cap omega..less than or equal to1 ..mu..b/sr compared to 7--22 ..mu..b/sr for peaks from (..pi../sup +/,p) reactions. The shape of the continuum in an excitation energy range of 10--40 MeV was found to be independent of pion charge and target. The ratios of (..pi../sup +/,p)/(..pi../sup -/,p) averaged over excitation energy and the ratios of the same reaction on different nuclei are presented. The magnitude of the proton yield in the low excitation continuum is more than 20 times larger for ..pi../sup +/ than for ..pi../sup -/, which supports a two-nucleon absorption model including pion charge exchange.

Research Organization:
Department of Physics, University of South Carolina, Columbia, South Carolina 29208
OSTI ID:
5977739
Journal Information:
Phys. Rev. C; (United States), Vol. 35:4
Country of Publication:
United States
Language:
English