The large set of accurate data on differential cross section and analyzing power from the CERN LEAR experiment on p̄p→π- π +, in the range from 360 to 1550 MeV/c, is well reproduced within a distorted wave approximation approach. The initial pp scattering wave functions originate from a recent N̄N model. The transition operator is obtained from a combination of the 3P0 and 3S 1 quark-antiquark annihilation mechanisms. A good fit to the data, in particular, the reproduction of the double-dip structure observed in the analyzing powers, requires quark wave functions for proton, antiproton, and pions with radii slightly larger than the respective measured charge radii. This corresponds to an increase in the range of the annihilation mechanisms, and consequently, the amplitudes for total angular momentum J=2 and higher are much larger than in previous approaches. The final-state ππ wave functions, parametrized in terms of ππ phase shifts and inelasticities, are also a very important ingredient for the fine tuning of the fit to the observables.
|Original language||English (US)|
|Number of pages||1260280|
|Journal||Physical Review C - Nuclear Physics|
|State||Published - Jul 2003|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics