The Panofsky Ratio value is of interest because it connects the pion-nucleon
scattering amplitude to the pion photoproduction amplitude, and it provides a
value with which several other low energy pion relations may be tested. For
example, the ratio R is defined as
From this ratio, and the assumption of the invariance of the electromagnetic
interaction under time reversal, one can calculate the reaction rate for
.
By extrapolating this calculated reaction rate for to
threshold, one can use the measured value of the Panofsky Ratio (P) to determine
the rate for the pion-nucleon scattering reaction 
. The resulting
equation is
where 
and 
are the center of mass momentum of the photon and
pion, respectively.
One can compare this calculation of 
to that obtained
from 
elastic scattering data. By using the principle of isospin
invariance for the extraction of from the scattering
data, and comparing the result with the calculation in Equation 1.18,
one can ultimately test the principle of isospin symmetry in the 
N
system. [19]
In addition to allowing useful calculations of the pion-nucleon scattering amplitude, the Panofsky Ratio reactions produce photons whose energies are comparable to that of the photons produced in the pion beta decay. By measuring the response of the PIBETA calorimeter to the photons resulting from the single charge exchange and pion capture reactions, one can predict the behavior of the calorimeter for the pion beta decay measurement.