[Rgc] Calculating P_T from double spin asymmetry

[Harut Avagyan]

Dear All,

For the scale factors used to calculate the P_T from inclusive 
asymmetries  we used, so far,   the sample for the raw asymmetry with 
<x>=0.25, and the following approximation:

to calculate the P_T

for NH3

* A_RAW/(PT*PB*f*D(y)=A_LL(<x>=0.25)=0.32 --> 
P_T=A/(0.32*0.83*0.178*0.7)=A_RAW*30.2

and

* 
A_RAW/(PT*PB*f*D(y)=A_LL(<x>=0.25)=0.17-->P_T=A/(0.17*0.83*0.265*0.7)=A_RAW*38.2

where A_RAW=(N^+ + N^-)/(N^+ + N^-) is the raw asymmetry in counts of 
N^+ (+- or -+)  and  N^-(++ or --) states with +/- being the helicities 
of the e- and the proton in CM.

The formula ignores the R (longitudinal part), and uses asymmetries from 
the polarized MC simulations we performed for the RGC (see below, and 
the slide 10 in 
https://clasweb.jlab.org/group_meeting_minutes/Physics/talks_2022/rc-report-08222022.pdf).

The dilution factor (0.178 for NH3 and 0.265 for ND3) are calculated 
from the same MC (see T.Hayward's proposal) counting ratios of 
contributions from polarized nucleons to the sum of unpolarized nucleons 
as a function of x, for both targets, and using the value at x=0.25.

Depolarization factor D(y)=\sqrt(1-eps^2), within cuts used for the 
sample is 0.7. The value used for the beam polarization is 0.83.

All above quantities can be calculated with better precision, including 
possible differences of free and nuclear nucleons.

Our current estimate for precision is that the values should be good 
within 20%, and should be good enough for monitoring purposes.

Best regards,

Harut


inbending----
/volatile/clas12/users/avakian/gemc5.0test/rgc-noemie-pplus/recon/
/volatile/clas12/users/avakian/gemc5.0test/rgc-noemie-pminus/recon/
/volatile/clas12/users/avakian/gemc5.0test/rgc-noemie-nplus/recon/
/volatile/clas12/users/avakian/gemc5.0test/rgc-noemie-nminus/recon/