Elastic scattering of low energy pions by nuclei and the in-medium isovector {pi}N amplitude

Journal Article · Thu Sep 01 04:00:00 EDT 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.72.034609· OSTI ID:20698992

Friedman, E; Kritchman, S; Yaari, G ^[1]; Bauer, M; Breitschopf, J; Clement, H; Denz, H; Doroshkevich, E; Erhardt, A; Meier, R; Wagner, G J ^[2]; Hofman, G J ^[3]

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1. Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)
2. Physikalisches Institut, Universitaet Tuebingen, D-72076 Tuebingen (Germany)
3. TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 and University of Regina, Regina, Saskatchewan, S4S-0A2 (Canada)

Measurements of elastic scattering of 21.5 MeV {pi}{sup {+-}} by Si, Ca, Ni, and Zr were made by using a single-arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a pion-nucleus optical potential were obtained from fits to all eight angular distributions put together. The anomalous s-wave repulsion known from pionic atoms is clearly observed and could be removed by introducing a chiral-motivated density dependence of the isovector scattering amplitude, which also greatly improved the fits to the data. The empirical energy dependence of the isoscalar amplitude also improves the fits to the data but, contrary to what is found with pionic atoms, on its own is incapable of removing the anomaly.

• OSTI ID: 20698992
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 3 Vol. 72; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
CALCIUM 40 TARGET
CALIBRATION
CHIRAL SYMMETRY
CHIRALITY
COULOMB SCATTERING
ENERGY DEPENDENCE
ISOVECTORS
MEV RANGE
MUONS
NICKEL 58 TARGET
NUCLEAR MATTER
OPTICAL MODELS
PION REACTIONS
PION-NUCLEON INTERACTIONS
PIONIC ATOMS
PIONS
POTENTIALS
S WAVES
SCATTERING AMPLITUDES
SILICON 28 TARGET
ZIRCONIUM 90 TARGET