Update ReinSehgalRESPXSec.cxx

[idkakorin]

The EM-factor should be as for KLNBS model.

[idkakorin]

Please, see the Eq.(4) of preprint

[jtenavidal]

RES on p

Pink - Igor's change Black - master RES on n

Differences seem bigger for n, but need to understand if it is due to binning of spline

[idkakorin]

@jtenavidal It is something strange, because the ratio _factor_new/factor_old=16\sin^4\thetaWeinberg. It is about 79-86% difference. The same difference should be in cross-sections.

[jtenavidal]

Hi Igor, I re-run both with the same inputs and now I get exactly the same. I run your code as follows:

source setup_GENIE.sh https://github.com/GENIE-MC/Generator.git idkakorin-patch-1 ;
gmkspl -p 11 -t 1000000010 -n 100 -e 15 --tune G18_10a_00_000 -o e_on_n_EMRES.xml --event-generator-list EMRES ;

and the master code as:

source setup_GENIE.sh https://github.com/GENIE-MC/Generator.git master ;
gmkspl -p 11 -t 1000000010 -n 100 -e 15 --tune G18_10a_00_000 -o e_on_n_EMRES.xml --event-generator-list EMRES ;

The setup_GENIE.sh file contains the code to pull it from git and set the right branch. In short, :

git clone https://github.com/GENIE-MC/Generator.git Generator/ 
cd Generator
git checkout "idkakorin-patch-1" 

Then it builds the code from scratch... Please correct me if i am wrong but the code above also affects the BS code right? I can't find it right now but I believe it inherits from it

[jtenavidal]

Sorry Igor, my bet. The BergerSehgal model is not affected by that file (https://github.com/GENIE-MC/Generator/blob/a7affedcaca8f70cc5c0ee9abaa0b2eeedfafe37/src/Physics/Resonance/XSection/BSKLNBaseRESPXSec2014.cxx#L486) as it should. I should have checked. I will run the tests now and then update the plots here.

[jtenavidal]

This is the effect on e-+n (RES). The change only affects the G18_01a configuration, which is not used

[jtenavidal]

With this change, the RS and BS predictions are consistent (black (G18_10a) and blue(G18_01a) ) . Red is G18_01a before the chaneg

[idkakorin]

Now the difference is as it should be.