Observation of Isobaric Analog States in Pion Single-Charge-Exchange Reactions

Helmut W. Baer; J. D. Bowman; M. D. Cooper; F. H. Cverna; C. M. Hoffman; Mikkel B. Johnson; N. S. P. King; J. Piffaretti; E. R. Siciliano; J. Alster; A. Doron; S. Gilad; M. Moinester; P. R. Bevington; E. Winkelmann

doi:10.1103/PhysRevLett.45.982

Observation of Isobaric Analog States in Pion Single-Charge-Exchange Reactions

Helmut W. Baer, J. D. Bowman, M. D. Cooper, F. H. Cverna, C. M. Hoffman, Mikkel B. Johnson, N. S. P. King, J. Piffaretti, E. R. Siciliano, J. Alster, A. Doron, S. Gilad, M. Moinester, P. R. Bevington, and E. Winkelmann

Phys. Rev. Lett. 45, 982 – Published 22 September 1980

Abstract

Isobaric-analog-state transitions have been observed throughout the periodic table in the ( $π^{+}$ , $π^{0}$ ) reaction. The forward-angle differential cross sections at $T_{π} = 98$ MeV on targets of C $H_{2}$ , ${}^{7}{Li}$ , ${}^{13}C$ , ${}^{27}{Al}$ , ${}^{58}{Ni}$ , ${}^{90}{Zr}$ , ${}^{120}{Sn}$ , and ${}^{208}{Pb}$ are reported. The $A$ dependence follows $(N - Z) A^{- \frac{4}{3}}$ , which is qualitatively understood in terms of a strong-absorption model. Optical-potential calculations which demonstrate the sensitivity to neutron density distributions and to the isospin dependence of higher-order dynamical effects are discussed.

Received 27 June 1980

DOI:https://doi.org/10.1103/PhysRevLett.45.982

Authors & Affiliations

Helmut W. Baer, J. D. Bowman, M. D. Cooper, F. H. Cverna, C. M. Hoffman, Mikkel B. Johnson, N. S. P. King, J. Piffaretti^*, and E. R. Siciliano

Los Alamos Scientific Laboratory, Los Alamos, New Mexico 87545

J. Alster, A. Doron, S. Gilad, and M. Moinester

Tel Aviv University, Ramat Aviv, Israel

P. R. Bevington and E. Winkelmann^†

Case Western Reserve University, Cleveland, Ohio 44106

^*Permanent address: Institut de Physique, Université de Neuchâtel, CH-2000 Neuchâtel, Switzerland.
^†Present address: Contraves (AG), Zürich, Germany.