[Halld-physics] Detector efficiency relation to Fr an phi0

[Michael Dugger]

Hi,

I have looked into the issue of how detector efficiency
influences the determination of normalization fraction (Fr)
and the offset angle.

If there is no cos(2*\phi) dependence in the unpolarized
data, then the way that Justin determines Fr is fine. If
the unpolarized does contain a cos(2*\phi) dependence we
should be able to correct for that.

For the offset angle, a 2nd or 4th sine moment in the
unpolarized data can cause a spurious offset. We just have
to check that those moments are not in the amorphous data.

A brief description of the calculations can be found at

https://userweb.jlab.org/~dugger/sigmaDecomp.pdf

Take care,
Michael