[Rivet] useInvisibles

[Frank Siegert]

Hi all,

since we were talking about a new release these days, I thought I'd 
mention that this one is still open as far as I know? I have it on my 
TODO list, but haven't managed to fix it yet. Do you think it's 
worth/feasible doing so for the imminent release, at least for the heavy 
flavour analyses where it becomes relevant (I'd probably need a day or 
two to implement and test)?

Frank

On 11/07/11 09:27, Jonathan Butterworth wrote:
> Just to say that all ATLAS analyses except the published W+jets paper
> use neutrinos and muons.
>
> The ATLAS default behaviour is to use all stable particles in the jet
> finder EXCEPT
> - prompt leptons
> - photons with a cone of 0.1 around prompt charged leptons.
>
> (These photons are generally summed with the lepton four vector instead).
>
> The upcoming (and currently preliminary) W+jets results also use this
> default behaviour.
>
> For technical reasons, this is not strictly implemented like this in all
> published ATLAS analyses, since prompt leptons and the photons are also
> input to the algorithm. But there is always a lepton/jet isolation which
> means that the difference is irrelevant given the local behaviour of
> anti-kT.
>
> Cheers,
> Jon
>
>
> On 08/07/2011 17:58, Andy Buckley wrote:
>> I think we need to revisit the jet config interface for the next release
>> -- with all the analyses that I know are in preparation and this
>> mismatch becoming more obvious by the minute we're clearly going to want
>> a 1.6.0. We can look into this when I'm down in Durham in a week or so...
>>
>> Andy
>>
>>
>> On 08/07/11 17:12, David Grellscheid wrote:
>>> Hi everyone,
>>>
>>> It seems that at the moment, neither of the two options does what ATLAS
>>> seems to want. From the code comments:
>>>
>>>> The default behaviour is that jets are only constructed from visible
>>>> (i.e. charged under an SM gauge group) particles. Some jet studies,
>>>> including those from ATLAS, use a definition in which neutrinos from
>>>> hadron
>>>> decays are included (via MC correction) in the experimental jet
>>>> definition.
>>>
>>> If useInvisibles is true, Rivet not only includes the neutrinos from
>>> hadron decays, but all invisibles. W+jets analyses should be careful
>>> there!
>>>
>>> See you,
>>>
>>> David
>>>
>>>
>>> PS: I still do not understand why one would want to correct for an
>>> undetectable particle, but we've had that discussion before.
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>>>
>>
>>
>