CGLN and Helicity 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 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 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 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:
Q² (GeV/c)²
W (MeV)
Q (deg)
increment
upper value

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