CGLN- Helicity- and Invariant Amplitudes
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 the Invariant Amplitudes A1,...,A6 we use the definition of F. Berends et al. Nucl. Phys. B4 (1967) 1


Channel: (pi0,p) (pi0,n) (pi+,n) (pi-,p)
Amplitudes: CGLN(F1,...,F6) Helicity(H1,...,H6) Invariant(A1,...,A6)
Choose kinematical variables

choose an independent (running) variable: Q² Q
choose values for Q², W, Q, step size and maximum value:
Q² (GeV/c)²
W (MeV)
Q (deg)
increment
upper value
click here

Change of model parameters: ( suppress output )

Born Rho Omega 
P33(1232) P11(1440) D13(1520) S11(1535) S31(1620)
S11(1650) D15(1675)  F15(1680) D33(1700) P13(1720)
F35(1905) P31(1910) F37(1950) 

Change of S-wave low-energy corrections and type of pi-N coupling (click here for details)
E0+
S0+
PS-PV mixing range parameter Lambda 

Change values of resonance couplings (relative to default values):
P33(1232)
S31(1620)
D33(1700)
A3/2
A1/2
S1/2
A1/2
S1/2
A3/2
A1/2
S1/2
F35(1905)
P31(1910)
F37(1950)
A3/2
A1/2
S1/2
A1/2
S1/2
A3/2
A1/2
S1/2

P11(1440)
D13(1520)
S11(1535)
S11(1650)
A1/2
S1/2
A3/2
A1/2
S1/2
A1/2
S1/2
A1/2
S1/2
D15(1675)
F15(1680)
P13(1720)
A3/2
A1/2
S1/2
A3/2
A1/2
S1/2
A3/2
A1/2
S1/2

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