Try Q2 Weighting from Charlotte

[c-dilks]

Try running with the weighting method from Charlotte Van Hulse:

Hello Chris,

Later than I wanted, but here how I weight my events:

I use as lumi values Ltotlow to normalise my events with 1<Q2<100 and Ltothigh for Q2>100 GeV2.
Here below how I obtain these values:

Ltot=(Ntot[0]/nEv18_275)*L18_275;
Ltotlow=(Ntot[1]/nEv18_275lowq2)*L18_275lowq2+Ltot;
Ltothigh=(Ntot[2]/nEv18_275highq2)*L18_275highq2+Ltot;

With Ntot[i]=total number of generated events, so entries in the trees.
Here, i=0 is for the files that cover Q2>1 GeV2; i=1 is for 1<Q2<100 and i=2 is for Q2>100 GeV2.

nEv18_275* are the total number of trials, which for the total sample at 18x275 GeV2 used for ecce were:
nEv18_275=20000000;
nEv18_275lowq2=20000000;
nEv18_275highq2=4000000;

The values L18_275* are the total MC luminosities, which I think Ralf provided you:
L18_275=22.650255;
L18_275lowq2=22.736391;
L18_275highq2=1293.659173;

I obtain them as follows:
TObjString* crossSection=(TObjString*)f->Get("crossSection");
TObjString* nEvents=(TObjString*)f->Get("nEvents");
Lumi+=(nEvents->GetString().Atof()/crossSection->GetString().Atof());

I then scale this Lumi as Lumi/=1e6 to obtain it in pb^-1.
(The nEvents correspond to the nEv18_275*)

More explanation about this is given here:
https://wiki.bnl.gov/eic/index.php?title=Simulations
in the section "MC Analysis Techniques".

I hope all is clear. Otherwise, please do not hesitate to ask.

greetings,

Charlotte