[Rivet] DISLepton Class fails to find outgoing lepton

[Andrii Verbytskyi]

Hi Marian, Andy, 

0) I see no attachment. It is hard to guess which kind of process will
produce electron+ some leptons from a single electron.
If that is not SM process, the code was not designed to handle BSM.
1) Yes, it is complicated with Sherpa. It merges too many things
together in one vertex. Just skip events with no electron/bad electron.
2) Everything "works" in "some way" with some conditions.
3) I cannot say without looking at the event that this is Sherpa
problem, but I suspect it is, so it is not clear if any fix is needed.


Best regards,
Andrii


On Tue, 2017-11-14 at 15:06 +0000, Andy Buckley wrote:
> Hi Marian,
> 
> Thanks for the report. I've CC'd Andrii, who provided that updated
> DISLepton logic. Andrii, can you comment on how we can fix this
> behaviour in a generator-independent way?
> 
> Andy
> 
> 
> On 10 November 2017 at 16:32, Marian Heil <marian.heil at durham.ac.uk> wrote:
> > Dear rivet authors,
> >
> > I think I found a bug in the DISLepton class in rivet version 2.5.4: It does
> > not find the outgoing lepton for a DIS scattering generated with Sherpa (the
> > corresponding HepMC file is attached).
> >
> > As far as I understand it in DISLepton::project the iteration over all
> > vertices and fails on the vertex "-6", because there are two outgoing
> > leptons ("10009" and "10015"). The first electron loops over vertex "-5"
> > back into vertex "-6" (for what ever reason), so it is not an actual final
> > state particle. The old code from version 2.5.3 does actually work for the
> > event.
> >
> > Cheers,
> > Marian
> >
> >
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> 
> 
>