Pion absorption process

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5229312

Doss, K G.R.

A study of pion absorption reactions is described in this thesis. Proton and deuteron production from low energy pion absorption in light nuclei have been measured leading to discrete and continuum states. The LEP beam line at LAMPF was used with a stack of 8 intrinsic germanium crystals developed by LBL and CMU for this experiment. The high resolution and large dynamic range of this detector allow us to measure a variety of reactions at the same time. The proton energy spectra are in general characterised by a broad bump at an energy approximately corresponding to ..pi../sup +/d ..-->.. pp reaction kinematics, suggestive of pion absorption on 2 nucleons. The (..pi../sup +/,p) as well as (..pi../sup +/,d) reactions generally favor transitions involving larger angular momentum transfer to the residual nucleus when states of similar nuclear structure are considered. The low energy excitation spectra from the (..pi../sup +/,p) reaction are similar to the spectra from (p,d) reaction on /sup 12/C and /sup 13/C. The (..pi../sup +/,d) reaction leading to the ground state of the residual nucleus has been seen for /sup 7/Li, /sup 12/C and /sup 13/C targets. The measured cross section for /sup 12/C(..pi../sup +/,d)/sup 10/C(0/sup +/ + 2/sup +/) reaction has a shape similar to that predicted by Betz and Kerman. The cross-section to the 2/sup +/ state is much higher than that for the ground state, whereas the calculation of Betz and Kerman gives them similar strengths. For the case of /sup 18/O, we see no counts for excitation energy of <10 MeV, at a sensitivity of approx. 100 nb/sr count, contrary to the predictions of Betz and Kerman. These features indicate a possible failure of their model for the (..pi../sup +/,d) reaction. The /sup 13/C target has the largest cross section (approx. 2 ..mu..b/sr at 35 degrees) among all the nuclei studied.

• Research Organization: Carnegie-Mellon Univ., Pittsburgh, PA (USA)
• OSTI ID: 5229312
• Country of Publication: United States
• Language: English

Related Subjects

651325* -- Nuclear Properties &amp; Reactions
A=6-19
Experimental-- Nuclear Reactions &amp; Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYONS
CAPTURE
CARBON 12 TARGET
CARBON 13 TARGET
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DEUTERONS
DIRECT REACTIONS
ELEMENTARY PARTICLES
FERMIONS
HADRON REACTIONS
HADRONS
KNOCK-OUT REACTIONS
LITHIUM 7 TARGET
MATHEMATICAL MODELS
MESON REACTIONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEONS
PION PLUS REACTIONS
PION REACTIONS
PROTON SPECTRA
PROTONS
SPECTRA
TARGETS