[Rivet] lifetimes in rivet

[Jonathan Butterworth]

yes, you have to correct for the decay products too; assumption is the 
whole decay is well understood. So it is a real (important) correction, 
but experimentally controllable in practice. e.g. Assuming you have 
acceptance for a substantial fraction of the decays for a given K_S 
momentum, the missing ones (which may unluckily be lost) are well known 
because the decay properties are well known.

Cheers,
Jon

Frank Siegert wrote:
> Jonathan Butterworth, Wednesday 07 April 2010:
>> All one is really doing here is correcting for a well-known
>> exponential, so I think it's pretty sound. One wouldn't do this for
>> anything but particles which are metastable, lifetimes > 10ps or so.
> 
> Sorry that I'm slow here, but don't you have to correct for their decay 
> products as well? Simplified example: Measuring charged multi in |eta|<2, 
> and you want to correct for all K_S as stable. Now your detector might 
> contain pi+ pi- from a K_S decay, possibly in |eta|<2, possibly not. Don't 
> you have to use a model for K_S decays to correct for that increase in 
> charged multi if you claim a measurement with *all* K_S stable?
> 
> This is purely out of interest. I agree that in such cases we shouldn't do 
> this in the Rivet analysis.
> 
> Frank

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Prof. Jonathan Butterworth,              http://www.hep.ucl.ac.uk/~jmb/
Physics and Astronomy Department                  Tel: +44 20 7679 3444
ATLAS, CERN                                       Tel: +41 22 76  72340
University College London                 Gower St, London WC1E 6BT, UK
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