[G8b_run] g8 meeting this week

[Brian Vernarsky]

Eugene,

Yes the momentum distribution is quite different in the MC vs the
data, which concerned me as well, however when I look at the momentum
distribution in the g11a MC I see the same type of spectrum so I have
just assumed that it is normal.  I suspect that it has to do with the
fact that the data contains all p,pi+,pi- events whereas the MC was
thrown as p,omega->p,pi+,pi-(pi0).  That still doesn't explain it
completely, but again since g11's MC looks the same I have assumed
that part is correct.  What I find interesting in those plots however
is the fact that the g11 data is quite smooth whereas the g8b data has
so many holes, especially towards the higher cos(theta) values.

I have checked that the events produced are correct events, they check
out just fine.  We have also fed the events through g11a's gsim and
they come out fine.

We did consider the torus field because there is clearly a difference
between the positive and negative particles.  The torus current was
only 8 A different from g11a however and was found to be input
correctly.  To be sure though we wildly varied the current and saw a
change, however not significant enough to be our problem, but it was
enough to prove that the current we were inputting was being read
properly.

I have not yet checked event by event to ensure the thrown and
reconstucted momenta are the same however.  I will look into it and
see what I can find.

Thanks,

Brian