[Rivet] CMS_2015_I1397174

[Markus Seidel]

Hi Andy,

I hope that future analyses just look for two high-pt leptons and are 
easier to implement then...
The problem is that many of the 8 TeV analyses explicitly veto W>tau 
decays. In dilepton it should be possible to search for exactly 2 
lepton+neutrino pairs that have a mass close to 80.4 GeV but in 
lepton+jets we would need to be able to identify hadronic tau decays to 
veto lepton+tau(had)+jets on particle level.

In fact, I forgot about the piece of code that deals with additional b 
jets. This is indeed heavily reliant on the HepMC record. We might 
consider splitting it in two analyses...

The b-tag is indeed without cut on the hadron pt. Is there a compelling 
reason for a cut? I think we discussed it once in the LHCTopWG but 
without outcome.

Cheers,
Markus


Am 19.07.2016 um 16:19 schrieb Andy Buckley:
> Requiring exactly 2 prompt (i.e. not-from-hadron-decay) charged leptons
> with substantial pT should do 99% of what's required, I think! This is
> pretty easy to do.
>
> But I saw some code in there which also categorises b-jets according to
> whether they come from top decay or not... so maybe the connection is
> deeper? Complex "HepMC digging" analyses like this can take a while for
> us to integrate, because we really need to go through them in detail and
> make sure everything makes sense & uses appropriate machinery.
>
> Andy
>
> PS. By the way, is there really no pT cut on the b-hadrons that you
> consider as tagging a jet? You can use e.g. jet.bTagged(Cuts::pT >
> 1*GeV), for example, or a similar argument to Jet::bTags()
>
>
> On 19/07/16 15:13, Markus Seidel wrote:
>> Hi Andy,
>>
>> thanks for the feedback!
>>
>> Actually, the parton level stuff is needed here only for selecting the
>> ttbar decay channel (dilepton ee/emu/mumu). Is there a better way to do
>> that?
>>
>> Cheers,
>> Markus
>>
>> Am 19.07.2016 um 15:57 schrieb Andy Buckley:
>>> On 19/07/16 14:47, Markus Seidel wrote:
>>>> Hi all,
>>>>
>>>> for some reason this analysis did not make it to the mailing list after
>>>> uploading (in April):
>>>> https://www.hepforge.org/archive/rivet/contrib/NEW/CMS_2015_I1397174.tgz
>>>>
>>>>
>>>> It contains jet multiplicity, pt, eta, etc... measured in ttbar events
>>>> at 8 TeV.
>>>
>>> Hi Markus,
>>>
>>> We've not yet incorporated this one because (as the code acknowledges)
>>> it uses a non-portable partonic top quark definition and introduces a
>>> lot of custom machinery that we need to merge carefully into the Rivet
>>> system.
>>>
>>> We've decided to allow partonic top definitions in "official" Rivet
>>> analyses, but have not provided the central machinery for that yet. When
>>> it is ready, this analysis will still require significant effort to
>>> include in the distribution... but in the meantime the code is still
>>> publicly available in the contrib directory for anyone who wants to
>>> use it.
>>>
>>> Cheers,
>>> Andy
>>>
>
>