[Halld-physics] pull distributions

[Elliott Wolin]

Hi,

See also "Probability and Statistics in Particle Physics", Frodesen et 
al., p 289 for a full discussion, including non-diagonal error matrices 
(which actually makes no difference if I read it correctly). 

				Sincerely,
					Elliott
 

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Elliott Wolin
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Curtis A. Meyer wrote:
> Hi Everyone -
>
>     I found a chapter of a PhD thesis that talks about
> kinematic fitting. Section 6.1.2 talks about the pull distributions and 
> formula
> 6.6 is as I remember it with the denominator having a difference inside the
> square root.
>
>     I also recall many years ago looking into what happens when the 
> error matricies
> are not diagonal. The denominator is defined only using the diagonal 
> elements
> of the covariance matrix, both for starting values and the fit values.
>
>     With regard for Simon's work, where he is looking at individual 
> tracks, I am
> not 100% sure how to apply this though. The error matrix is the result 
> of the fit.
> In Jake's work, it is clearer a we have the pull's from the tracking, 
> and then the
> improved pulls after the kinematic fit.
>
>     I have placed the chapter (6) on the portal as GlueX-doc-1635:
>
>     Other references include:
>
>     Eadie, W. T. et al., Statistical methods in experimental physics 
> (North-Holland, Amsterdam, 1986).
>
>    V. Blobel, Least squares methods, p. I 27, in Bock, R. K. et al. 
> (eds.), Formulae and methods
>    in experimental data evaluation with emphasis on high energy physics. 
> (European Phys. Soc.,
>    1984)
> curtis
>
>