[Rivet] lifetimes in rivet

[Jonathan Butterworth]

I think I agree.

The advantage would (might) be e.g. if there were several different 
analyses with slightly different stability criteria, one could run the 
them in a single run this way, rather than having separate generator 
runs for each. But its a bit hypothetical. The only case I'm aware of is 
whether b hadrons are left stable or not, and I think this is already 
handled.

Cheers,
Jon

James Monk wrote:
> On 7 Apr 2010, at 09:45, Jonathan Butterworth wrote:
> 
>> I suspect that one could build a variant of the final state projection 
>> which studied the decay history, and if certain particles which should 
>> have been "stable" has been decayed by the generator, removed their 
>> decay products and added back the original. However, there's no way 
>> rivet could do the opposite (i.e. decay a particle which should have 
>> been decayed but which the generator left stable). At best it could flag 
>> up an error "particle should have been decayed according to the lifetime 
>> criteria of this analysis, but wasn't"
> 
> That sounds to me like it might impinge upon generator independence a bit (I can imagine Tauola-hell in navigating back up the event history, for example).  What would be the advantage, other than saving the end user from having to know the details of what their generator is doing, and do we really want to encourage that?
> 
> cheers,
> 
> James
> 

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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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