The following relations between CGLN
amplitudes and helicity
amplitudes will be used in our calculations.
(click here
for a larger image)
Further details can be found in D. Drechsel and
L. Tiator , J. Phys. G 18 (1992) 449-497 (scanned
version) (for expressions with CGLN amplitudes) and G. Knöchlein,
D. Drechsel and L. Tiator, Z. Phys. A 352 (1995) 327-343 (for expressions
with helicity amplitudes) postscript
compressed (431 kB) and nucl-th/9506029
.Channel: (pi0,p) (pi0,n) (pi+,n) (pi-,p)
Amplitudes: CGLN(F1,...,F6) Helicity(H1,...,H6) Spin(S1,...,S6)
Model parameters: Born Rho Omega P33(1232) P11(1440)
D13(1520) S11(1535) S31(1620) S11(1650) F15(1680) D33(1700)
Change
values of resonance couplings (relative to standard values):
P33(1232)
S31(1620)
D33(1700)
M1+
E1+
S1+
E0+
S0+
M2-
E2-
S2-
P11(1440)
D13(1520)
S11(1535)
S11(1650)
F15(1680)
M1-
S1-
M2-
E2-
S2-
E0+
S0+
E0+
S0+
M3-
E3-
S3-
Choose kinematical variables
choose an independent (running)
variable: Q² W Q
choose values for Q², W, Q,
step
size and maximum value: