[Rivet] (short) Rivet question

[Andy Buckley]

Hi Raquel,

You can convert the LHE files direct to HepMC, but it is a hack. Also,
there are of course physics effects in the shower, hadronisation, etc.
which might be important for your results -- unless you have a good reason
not to, I would shower them. This will also make life easier since Rivet's
ZFinder reconstructs Zs from lepton pairs (you have to do something else if
you have hadronically decaying bosons), and is generally oriented around
the idea of doing physics analysis from a "realistic" set of final state
particles.

When showering, you will need to match the shower to your 2-jet final
state: in fact, in general your final-state topology will receive
contributions from Z Z + 2 shower-jets and Z Z j + 1 shower-jet, so unless
you are placing analysis cuts on the jets which would eliminate these
contributions you should also be telling MadGraph to make and merge those
different matrix elements.

Andy


On 25 May 2018 at 16:38, GOMEZ-AMBROSIO, RAQUEL <
raquel.gomez-ambrosio at durham.ac.uk> wrote:

> Dear Andy,
>
>
> I am Raquel, from IPPP, I am currently trying to use rivet for an analysis
> but I am a bit confused with the material I found. I wrote a Rivet analysis
> in the past, for CMS, and I liked it quite much, however now, trying to use
> the same analysis for my own private MC productions is a bit more
> challenging. I just have 3 short questions:
>
>
> 1) My output files are lhe events from Madgraph.  Can I just use this
> wrapper ouf yours  (https://rivet.hepforge.org/hg/contrib/file/tip/
> lhef2hepmc/ )  to transform them to hepmc, or is there some subtlety I
> should take into account?
>
>
> 2) I am studying resonant production of 2 Zs and hence my final state is Z
> Z j j . Is this Ok with Rivet? or I have to decay the Zs to leptons to be
> able to run the analysis?
>
>
> 3) I am not doing Parton shower either, but I could do if it was
> necessary. Is it?
>
>
>
> thanks a lot
>
> Raquel
>
>
>


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