Pion absorption on {sup 3}He at low energies

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.53.1074· OSTI ID:279112

Hahn, H; Altman, A; Ashery, D; Gefen, G; Gill, D R; Johnson, R R; Levy-Nathansohn, R; Moinester, M A; Sevior, M; Trelle, R P ^[1]

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1. Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, 69978 Ramat Aviv (Israel)

The reactions {sup 3}He({pi}{sup +},{ital pp}){ital p} and {sup 3}He({pi}{sup {minus}},{ital pn}){ital n} were studied at 37.0 MeV by coincidence detection of two nucleons. The differential cross sections were separated to two-nucleon ({sigma}{sub 2{ital N}}), three-nucleon ({sigma}{sub 3{ital N}}), and final-state interaction ({sigma}{sub FSI}) components. For {pi}{sup +}, the {sigma}{sub 2{ital N}} angular distribution is symmetric about 90{degree}, and the total cross section is 1.5 times the cross section measured for {ital d}({pi}{sup +},{ital pp}). For {pi}{sup {minus}}, the angular distribution is asymmetric (backward peaked). The asymmetry increases with decreasing energy, indicating increasing pion {ital s}-wave contribution at lower energies. The fraction of the cross section induced by {ital s}-wave pions as calculated by a partial wave amplitude analysis is 13{percent}. The measured total cross sections are {sigma}{sub 2{ital N}}({pi}{sup {minus}})=0.85{plus_minus}0.08 mb and {sigma}{sub 2{ital N}}({pi}{sup +})=7.9{plus_minus}0.5 mb; {sigma}{sub 3{ital N}}({pi}{sup {minus}})=1.6{plus_minus}0.7 mb and {sigma}{sub 3{ital N}}({pi}{sup +})=1.3{plus_minus}0.3 mb. A new evaluation of {sigma}{sub 3{ital N}} at {ital T}{sub {pi}}=62.5 and 82.8 MeV is given, using data from an earlier experiment. The cross sections leading to the two-nucleon final-state interaction at {ital T}{sub {pi}}=37.0 MeV are also estimated. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 279112
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 3 Vol. 53; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ABSORPTION
ANGULAR DISTRIBUTION
ASYMMETRY
COINCIDENCE METHODS
DIFFERENTIAL CROSS SECTIONS
ENERGY DEPENDENCE
FINAL-STATE INTERACTIONS
HELIUM 3 TARGET
MEV RANGE 10-100
NEUTRONS
PARTIAL WAVES
PION MINUS REACTIONS
PION PLUS REACTIONS
PROTONS
S WAVES
TOTAL CROSS SECTIONS