Negative pion absorption at rest in [sup 3]He

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.51.469· OSTI ID:6642740

Gotta, D; Doerr, M; Fetscher, W; Schmidt, G; Ullrich, H ^[1]; Backenstoss, G; Izycki, M; Kowald, W; Schwanner, I; Weber, P; Weyer, H J ^[2]

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1. Kernforschungszentrum Karlsruhe, Institut fuer Kernphysik und Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe, D-76344 Karlsruhe (Germany)
2. Institut fuer Physik, Universitaet Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

The [ital pnn] and [ital dn] final states after the absorption of stopped pions in [sup 3]He have been measured in a kinematically complete experiment covering the whole phase space. Proton-neutron, deuteron-neutron, and neutron-neutron coincidences have been detected with a charged-particle hodoscope and large-area time-of-flight counters. For the first time, triple coincidences between the pionic [ital K] x rays and two particles have been measured thus selecting absorption from the atomic 1[ital s] state. It has been found that the absorption is dominated by the two-nucleon mechanism (2NA) on isoscalar nucleon pairs as indicted by the measured ratio of 6.3[plus minus]1.1 for back-to-back correlated [ital nn] and [ital pn] pairs. A substantial amount of the three-body final state [ital pnn] is affected by the final-state interaction (FSI) or leads to the two-particle final state [ital dn]. Ratios of 3.1[plus minus]0.4 for 2NA to FSI and of 4.2[plus minus]0.6 for the [ital pnn] to the [ital dn] final state are measured. No evidence has been found for three-nucleon absorption with an upper limit of %/[pi][sub stop][sup [minus]].

• OSTI ID: 6642740
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 51:2; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

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663460* -- Meson- & Hyperon-induced Reactions & Scattering-- (1992-)
664500 -- Special Atoms & Molecules-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
BARYON-BARYON INTERACTIONS
BOSONS
CHARGED PARTICLES
COINCIDENCE METHODS
COINCIDENCE SPECTROMETRY
COUNTING TECHNIQUES
ELEMENTARY PARTICLES
EVEN-ODD NUCLEI
FINAL-STATE INTERACTIONS
HADRON-HADRON INTERACTIONS
HADRONS
HELIUM 3
HELIUM ISOTOPES
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL SPACE
MESONS
NEUTRON-DEUTERON INTERACTIONS
NEUTRON-NEUTRON INTERACTIONS
NUCLEI
NUCLEON-DEUTERON INTERACTIONS
NUCLEON-NUCLEON INTERACTIONS
PARTICLE INTERACTIONS
PHASE SPACE
PIONS
PROTON-NEUTRON INTERACTIONS
PROTON-NUCLEON INTERACTIONS
PSEUDOSCALAR MESONS
SORPTION
SPACE
STABLE ISOTOPES
TIME-OF-FLIGHT METHOD