[Rivet] electroweak results used to tune/validate theory

[Andy Buckley]

I must be missing something here: we are just saying that for tuning &
theory purposes, it's important to have results that use minimal
MC-derived unfolding, i.e. we really need what was actually measured! In
the case I mentioned, this wouldn't be the "Z pT", but the
detector-corrected pT of dileptons with cone-summed photons.

Surely it's publishing (as has been done) the "Z pT" that requires
extracting the correction factor for PHOTOS, i.e. either making two full
MC samples or, more dangerously, trying to strip off "PHOTOS photons"
from the event record. Or am I missing something?

Best wishes,
Andy


Heidi Schellman wrote:
> 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
>>
>>   


-- 
Dr Andy Buckley
Institute for Particle Physics Phenomenology
Durham University
0191 3343798 | 0191 3732613 | www.insectnation.org