Speaker
Dr
Sergey Dymov
(FZ-Juelich)
Description
An experimental program to study near threshold pion production in the
reactions pp->{pp}_s \pi^0 and pn->{pp}_s \pi^-, is undertaken at
ANKE-COSY. The selection of the final proton pair {pp}_s in the 1S0 state,
realized by cutting on the pair excitation energy E_{pp}<3 MeV, simplifies
the theoretical analysis of the processes. The combined study of these
reactions is motivated by the extension of Chiral Perturbation Theory ChiPT
to pion production in NN collisions. The measurement of dSigma/dOmega,
A_y^p and the spin-correlation coefficients A_{x,x} and A_{y,y} will
provide a non-trivial test of the ChiPT predictions, and lead to the isolation
of the strength parameter d of the four-nucleon-pion contact interaction in ChiPT.
Use of the polarized COSY beam and the ANKE polarized internal target allows
one to conduct single and double polarisation experiments. The results of the
measurement of dSigma/dOmega, A_y^p in the two processes, carried out
with the polarized proton beam, will be reported. The first analysis of the recent
double polarized measurement of A_{x,x} and A_{y,y} in pn->{pp}_s \pi^-,
conducted with a polarized deuteron beam and a polarized hydrogen target, will
also be presented.
Primary author
Dr
Sergey Dymov
(FZ-Juelich)
