Search for deeply bound pionic states in sup 208 Pb using the sup 208 Pb( n , p ) reaction at T sub n =418 MeV

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.43.1099· OSTI ID:6199551

Iwasaki, M; Trudel, A; Celler, A; Haeusser, O; Hayano, R S; Helmer, R; Henderson, R; Hirenzaki, S; Jackson, K P; Kuno, Y; Matsuoka, N; Mildenberger, J; Miller, C A; Outa, H; Sakai, H; Toki, H; Vetterli, M; Watanabe, Y; Yamazaki, T; Yen, S ^[1]

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1. Department of Physics and Meson Science Laboratory, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan (JP) Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, Japan Research Center for Nuclear Physics, Osaka University, Ibaragi, Osaka 567, Japan Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 Department of Physics, Tokyo Metropolitan University, Setagaya, Tokyo 158, Japan

A search for deeply bound {pi}{sup {minus}} states in heavy nuclei was undertaken using the pion-transfer {sup 208}Pb({ital n},{ital p}) reaction at the TRIUMF CHARGEX facility. Monoenergetic 418-MeV neutrons from the {sup 7}Li({ital p},{ital n}) reaction were used to induce ({ital n},{ital p}) reactions on a segmented {sup 208}Pb target. The spectrum between 100- and 180-MeV excitation energy was measured with an energy resolution of 1.15 MeV (FWHM). In the region of 120--140 MeV, where the deeply bound pionic states were expected, the observed spectrum exhibited a smooth continuumlike behavior with a cross section of {approx}0.8 mb/sr MeV. This resulted in an upper limit of 0.35 mb/sr for the production cross section of {pi}{sup {minus}} bound states in {sup 208}Pb. This cross section is substantially smaller than the estimate based on the plane-wave impulse approximation, showing the importance of the effect of distortion. The distortion effect is calculated and discussed.

• OSTI ID: 6199551
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 43:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651920* -- Nuclear Properties & Reactions
A=190-219
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ATOMS
BARYON REACTIONS
CROSS SECTIONS
DISTORTED WAVE THEORY
ENERGY RANGE
HADRON REACTIONS
HADRONIC ATOMS
LEAD 208 TARGET
MESIC ATOMS
MEV RANGE
MEV RANGE 100-1000
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
PIONIC ATOMS
PRODUCTION
TARGETS