Pion elastic scattering and the (. pi. ,. pi. prime p) reaction on sup 4 He in the. Delta. sub 3,3 region

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5395367

Jones, M K

Measurements and analyses of {pi}{sup +} and {pi}{sup {minus}} elastic scattering, and ({pi}{sup +}, {pi}{sup +}{prime} p) and ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} p) reactions on {sup 4}He are presented. Both experiments were done at the Los Alamos Meson Physics Facility using the Energetic Pion Channel and Spectrometer. The {sup 4}He({pi},{pi}) elastic scattering cross sections were measured for {pi}{sup +} scattering at scattering angles {theta}{sub lab} = 110{degree}-170{degree} and five incident energies between T{sub {pi}} = 90 and 180 MeV. Elastic {pi}{sup {minus}} cross sections were measured only at T{sub pi} = 180 MeV. The {sup 4}He({pi},{pi}{prime} p) angular correlation functions were measured for {pi}{sup +} and {pi}{sup {minus}} at T{sub {pi}} = 180 and {theta}{sub {pi}{prime}} = 30{degree}, 40{degree}, 60{degree}, 80{degree} and at T{sub {pi}} = 140 MeV and {theta}{sub {pi}{prime}} = 40{degree}. The ({pi},{pi}{prime} p) data were analyzed by a distorted wave impulse approximation code 3DEE. 3DEE models the ({pi},{pi}{prime} p) reaction as a pion-induced proton knock-out and includes distortions in the incident pion, the outgoing pion, and the emitted proton waves. The calculations give R{sub {pi}p} between 6 and 9 at all proton and pion angles. The {pi}{sup +} calculations reproduce the absolute {pi}{sup +} cross sections fairly well. The {pi}{sup {minus}} calculations have a peak in the angular correlation function near the quasi-free angle, in contrast to the {pi}{sup {minus}} data which displays a flat distribution. At proton angles near 180{degree} in the center of mass of the struck mass 4 system, the measured {pi}{sup {minus}} cross sections are larger than the {pi}{sup +} cross section which is the reverse of the ratio at 0{degree}. These features of the measured {pi}{sup {minus}} cross sections indicate that interference between a quasi-free process and another process is important in the ({pi},{pi}{prime} p) reaction.

• Research Organization: Minnesota Univ., Minneapolis, MN (United States)
• OSTI ID: 5395367
• Country of Publication: United States
• Language: English

Related Subjects

663460* -- Meson- & Hyperon-induced Reactions & Scattering-- (1992-)
663510 -- Nuclear Mass Ranges-- A=1-5-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYONS
CHARGED-PARTICLE REACTIONS
COUNTING TECHNIQUES
DATA
DIRECT REACTIONS
DISTORTED WAVE THEORY
ELASTIC SCATTERING
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
HADRON REACTIONS
HADRONS
HELIUM 4 TARGET
INFORMATION
MESON REACTIONS
NUCLEAR REACTIONS
NUCLEONS
NUMERICAL DATA
OPTICAL MODELS
PION MINUS REACTIONS
PION PLUS REACTIONS
PION REACTIONS
PROTONS
QUASI-FREE REACTIONS
SCATTERING
SCINTILLATION COUNTING
TARGETS