Re: [BLAST_ANAWARE] asymmetries vs ...

From: richard milner (milner@mitlns.mit.edu)
Date: Mon Sep 08 2003 - 09:52:30 EDT


Vitaliy,
I agree. Why not use the total asymemtry averaged over all Q^2?
Richard

On Mon, 8 Sep 2003, vitaliy ziskin wrote:

> I think that to find a correlation between the AF and the dilution it is
> best to use a chi squared minimization that is used in show_ep_asym2.C
> Right now we are trying to see this correlation by looking at the
> asymmetry in the lowest Q^2 point. This is not as sensative let alone
> it has large error bar. The reson why TB cannot make any conclusion
> about the AF dependence is due to large error bars. If we use full
> acceptance (24-50) we reduce the error bar in the dilution. I'm working
> on calculating the error bar for the dilution from knowing the chi square.
>
> Cheers, Vitaliy
>
> Tancredi Botto wrote:
>
> >Hi ben, jason
> >thanks for the good work and extensive update. I think it is good
> >progress but needs to be pushed a bit forward. Comments:
> >
> >
> >_ For the beam current dependent asymmetries: it'd be surprising
> > that we have different L/R results only at low current. I am sure
> > you checked that the same cuts are used l/r. But are there any other
> > differences ?? Are the yields & their distributions the same ? This
> > you can easily check "by hand", using the integrated charge for I<75..
> > (you have the charge files)
> >
> >_ For af dependent asymmetries: if I exclude the 3rd data point
> > on the three bottom panel then I can hardly conclude anything. It may
> > point to a problem in data/analysis/af-measurament local to that time.
> > It may be worth while to look for possible problems there. You can
> > easily add a "yields" plot right ?
> >
> >I agree with extirpating the "bad" fills although I have no solution on
> >how to find/cut them (except by hand..). We have to first understand if
> >they really make an impact, since we are dealing with few events and they
> >seem nicely distributed (by eye).
> >
> >Also about the AF correlation: you take the low-Q2 bin as the "asymmetry
> >value". I think it is more logical to take the dilution factors proper,
> >with their error bar. These can be calculated in the same loop that
> >calculates the chi2 in show_ep_asym2.C and are the only "junk" indicator
> >we have. The sum L+R dilution factor can be just the average weighted
> >by 1/errbars2
> >
> >
> >Sorry to bother you, have fun!
> >-- tancredi
> >
> >________________________________________________________________________________
> >Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> >research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> >
>
>
>



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