[Rivet] electroweak results used to tune/validate theory

[Heidi Schellman]

Yes, but taking PHOTOS out means regenerating millions of full MC 
events... and making certain that one's colleagues don't get the wrong 
set...

Andy Buckley wrote:
> Heidi Schellman wrote:
>   
>> One issue here - we do use photos in our MC, but that is partially 
>> because, we also have real photon radiation from the detector - which is 
>> almost certainly a larger effect.  At least for the total Z cross 
>> section, we found that if we use a .2 cone for electrons in D0, photos 
>> or not photos made very little effect in our results.
>>     
>
> Gavin did the detailed study, so he can probably comment more
> knowledgeably than I, but the effect was around 5% for for Z pT peak
> position, which is sensitive to low pT effects like QED resummation. I
> would expect that inclusive quantities like total cross-section are
> relatively unaffected, but for Monte Carlo tuning the differential ones
> are essential.
>
>   
>> And we are going to quote for our fiductial PT, eta range, as well as 
>> for the full extrapolated range.
>>     
>
> Excellent! I hope it's clear that what we're advocating is publishing
> purely detector-corrected data "as well as" any extrapolations or theory
> unfoldings... rather than "instead of"!
>
> Andy
>
>