Analysis of double charge exchange of pions on 4He

Physical Review, 1965

Pions offer a unique possibility as probes of nuclear structure since they can exchange two units of electrical charge unaccompanied by other quantum numbers. We have calculated the double-charge-exchange cross section for the reaction π-+He3-->π++3n in the impulse approximation using the Chew-Low model for the pion-nucleon interaction. Only the dominant 3-3 channel is retained. For incident pions in the energy region of several hundred MeV, values of the differential cross section of d2σdΩdE~1-10 μb/MeV are obtained for forward angles. Triple-scattering terms are also calculated and found to introduce corrections of <10% in d2σdΩdE. Similar results are obtained when the work is extended to the reaction π++O18-->π-+Ne18 using shell-model wave functions.

Physical Review C, 2007

The pion double charge exchange amplitude is evaluated in a composite-meson model based on the four-quark interaction. The model assumes that the mesons are two-quark systems and can interact with each other only through quark loops. To evaluate the meson exchange current contribution, the form factors of the two-pion decay modes of the ρ, σ , and f 0 mesons have been used in the calculations. The contribution of the four-quark box diagram has been taken into account as well as a contact diagram. The contributions of the ρ, σ , and f 0 mesons increase the forward scattering cross section, which depends weakly on the energy.

Nucl Phys a, 2007

1960

ricevuto il 18 Giugno 1965)

PHYSICAL REVIEW C, 58, 1998

Results from a measurement of the reaction 2H(π+,pp)π° at Tπ+=239MeV are presented. Because two protons were detected, the measurement was sensitive to events which involved both nucleons in a substantial way. Differential distributions are compared to the predictions of simple models. An integrated cross section for SCX (single charge exchange), with the emission of two protons each with kinetic energy >25MeV, is presented.

Physical Review C, 1987

Data are presented for pion double charge exchange on targets of Ca, ' Fe, ' Ni, ' Se, Zr, and " Sn. These and earlier data are used to examine the mass dependence of double-isobaric-analog transitions and nonanalog ground-state-to-ground-state transitions in the energy region T =100 to 300 MeV. The implications of the mass dependence to the interpretations of the underlying reaction mechanisms of double charge exchange are discussed.

Physical Review C, 1998

We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident π − kinetic energy in the center of momentum angular range between 0 • and 55 •. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.