Observables

A couple of words about A_xx and how to measure it:

A_xx is an asymmetry so take advantage of numerator denominator systematics cancellation:

1.) Measure N_p and N_u with same cup same exact material
2.) Use same B-field
3.) Use NMR on both to measure polarization and un-polarization
4.) Let beam heating an off larmor microwave control un-polarization
5.) Keep both cold (~1K)
6.) Switch from pol to unpol frequently

For unpolarized electron beam the helicity dependent cross sections are:
Where in the deuteron rest frame the spin is quantized in the direction of the virtual photon

This means there is a direct relationship to first component analyzing power

which is very much accessible with e+D->e+N+X

In addition we have a direct relationship to b1 for low x but be weary uncertainties