[Rivet] Question concering PromptFinalState projection

[Andy Buckley]

Exactly. I think we may be now more than 10 years past the point that it 
was declared superseded and unsupported ;-)

Andy


On 25/01/17 19:10, Christian Gutschow wrote:
> Hi,
>
> the Rivet routines work perfectly fine with the Herwig shower (!) — it’s
> just Fortran Herwig that doesn’t comply with the HepMC standard, for
> which the routines might not work. All the more reason to move to the
> modern incarnations of Herwig...
>
> Cheers,
> Chris
>
>> On 25 Jan 2017, at 17:31, Dominic Hirschbuehl <dhirsch at mail.cern.ch
>> <mailto:dhirsch at mail.cern.ch>> wrote:
>>
>> Hi Andy,
>>
>> thanks a lot for the quick answer.
>> It is indeed Fortran Herwig and I ran over a MC12 sample. Maybe the
>> rewriter was not used for this sample.
>>
>> However, does this mean, that we need to put some disclaimer to our
>> Rivet routines, that they don't work for the Herwig shower, since
>> everybody outside ATLAS won't have the rewriter, right?
>>
>> Cheers
>>  Dominic
>>
>> On Wed, Jan 25, 2017 at 05:24:21PM +0000, Andy Buckley wrote:
>>> Hi Dominic,
>>>
>>> Is this *Fortran* Herwig?
>>>
>>> Indeed it uses non-standard status codes, so Rivet's algorithms will
>>> break. But in ATLAS we added a Herwig status rewriter, to make it
>>> compliant -- is that not being used in your sample?
>>>
>>> The restriction to look at status 2 only (because status 1 can't be
>>> an ancestor) is maybe a bit extreme: we could also allow status
>>> codes > 10 to be used (the MC range if I remember correctly). But
>>> then we wouldn't know what sort of generator-dependence we'd be
>>> introducing: for example Herwig++ uses status 11 for everything that
>>> isn't 1, 2, or 4 so we could end up walking up precisely the sort of
>>> unphysical debug trees that the code is trying to avoid...
>>>
>>> Short answer: the generator needs to be compliant with the HepMC
>>> status scheme. But I thought we had already modified FHerwig in that
>>> way.
>>>
>>> Andy
>>>
>>>
>>> On 25/01/17 16:55, Dominic Hirschbuehl wrote:
>>>> Dear all,
>>>>
>>>> I have a question concerning the PromptFinalState projection.
>>>> I did a study on acceptences of lep+jets ttbar events, where I found an
>>>> unexpected differences between Powheg+Pythia6 and Powheg+Herwig samples.
>>>> The differences occured already on the level of the lepton acceptance,
>>>> which includes a dilepton veto.
>>>>
>>>> After some investigation I have the suspicion, that leptons from hadron
>>>> decays are counted as prompt leptons.
>>>>
>>>> Looking to the actual implementation of isPrompt I found this line
>>>> of code:
>>>> if (ancestor->status() != 2) continue; // no non-standard statuses or
>>>> beams to be used in decision making
>>>>
>>>> Is there a reason to restrict the status codes to 2?
>>>> If I print out all ancestors of a "prompt lepton" from a Herwig
>>>> showered event
>>>> I get:
>>>>
>>>>   pdg = 2212 status = 101 0 1
>>>>   pdg = 2212 status = 102 0 1
>>>>   pdg = 21 status = 121 1 0
>>>>   pdg = 21 status = 122 1 0
>>>>   pdg = 6 status = 123 1 0
>>>>   pdg = 6 status = 143 1 0
>>>>   pdg = 6 status = 3 1 0
>>>>   pdg = 6 status = 155 1 0
>>>>   pdg = 24 status = 123 0 0
>>>>   pdg = 24 status = 3 0 0
>>>>   pdg = 24 status = 155 0 0
>>>>   pdg = 4 status = 124 1 0
>>>>   pdg = 4 status = 144 1 0
>>>>   pdg = 4 status = 2 1 0
>>>>   pdg = 21 status = 2 1 0
>>>>   pdg = 4 status = 158 1 0
>>>>   pdg = -2 status = 158 1 0
>>>>   pdg = 91 status = 183 0 0
>>>>   pdg = 411 status = 197 0 1
>>>>
>>>> which would indicate that the identified lepton actually comes fomr a
>>>> hadron.
>>>>
>>>> Do I miss something?
>>>>
>>>> Thanks in advance
>>>> Dominic
>>>>
>>>>
>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> Dr Andy Buckley, Lecturer / Royal Society University Research Fellow
>>> Particle Physics Expt Group, University of Glasgow
>>
>> --
>> /---------------------------------------------------------------------\
>> |                     Dr. Dominic Hirschbuehl                           |
>> \   Bergische Universitaet Wuppertal - Exp. Elementarteilchenphysik   /
>> /  hirsch at physik.uni-wuppertal.de
>> <mailto:hirsch at physik.uni-wuppertal.de> / dominic.hirschbuehl at cern.ch
>> <mailto:dominic.hirschbuehl at cern.ch>       \
>> |       office : D.09.22    phone  : 0049 - 202 - 439 - 3751
>>           |
>> \---------------------------------------------------------------------/
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>
>
>
>
>  —
>
>  Dr. Christian Gütschow
>
>  Department of Physics and Astronomy
>  University College London
>  Gower Street
>  London WC1E 6BT
>
>  > D10 Physics Building
>  > +44 (0)20 7679 3775
>  > chris.g at cern.ch <mailto:chris.g at cern.ch>
>
>
>
>


-- 
Dr Andy Buckley, Lecturer / Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow