[Rivet] possible issues with WFinder?

[David Grellscheid]

Hi Raghav,

it would help us a lot if you could implement both methods in a single 
minimal analysis cc file which is ready to be used, filling one histo each.

One difference I can see at the moment is that individual neutrinos 
aren't used in WFinder. It uses missing E.

See you,

   David


On 19/05/2016 15:31, Raghav Kunnawalkam Elayavalli wrote:
> Hi Rivet Experts,
>
> I think there might be something happening with the WFinder in the latest version of Rivet. Ive attached two invariant mass plots here and [1] is using the WFinder and [2] is what i estimate by hand. You can see a big difference in the distributions even for pp at 2.76 TeV. When we do our heavy ion events we lose a whole lot of Z's which are recovered by estimating by hand. Yes, there are a few differences in the two methods, but between 0.1 and 0.2 in delR and missing ET cut, i dont think it should be such a huge difference?
>
> Cheers
> Raghav
>
> [1]       WFinder wfinder(fs, Cuts::abseta < 3.0 && Cuts::pT > 20*GeV, PID::MUON, 0.0*GeV, 1000.0*GeV, 25.0*GeV, 0.2);
>
> [cid:84252C3A-9047-425F-90A1-0527877B491B at cern.ch]
> [2] in the init() method:
>        IdentifiedFinalState allleptons;
>        // allleptons.acceptIdPair(PID::ELECTRON);
>        allleptons.acceptIdPair(PID::MUON);
>        Cut cuts = Cuts::abseta < 2.5 && Cuts::pT > 20*GeV;
>        DressedLeptons leptons(fs, allleptons, 0.1, cuts);
>        addProjection(leptons, "leptons");
>
>        // Leading neutrinos for Etmiss
>        LeadingParticlesFinalState neutrinos(fs);
>        // neutrinos.addParticleIdPair(PID::NU_E);
>        neutrinos.addParticleIdPair(PID::NU_MU);
>        neutrinos.setLeadingOnly(true);
>        addProjection(neutrinos, "neutrinos");
>
> in the analyze() method:
>        // implementation of simple Wfinder
>        const vector<DressedLepton>& leptons = applyProjection<DressedLeptons>(event, "leptons").dressedLeptons();
>        Particles neutrinos = applyProjection<FinalState>(event, "neutrinos").particlesByPt();
>        if (leptons.size() != 1 || (neutrinos.size() == 0)) {
> vetoEvent;
>        }
>
>        FourMomentum lepton = leptons[0].momentum();
>        FourMomentum p_miss = neutrinos[0].momentum();
>        if (p_miss.Et() < 25.0*GeV) {
> vetoEvent;
>        }
>
>        double invMass = sqrt(2.0 * lepton.pT()/GeV * p_miss.pT()/GeV * (cosh(lepton.eta()-p_miss.eta()) - cos( lepton.phi()-p_miss.phi()) ) );
>        _h_W_massCheck->fill(invMass, weight);
>
> [cid:375AF03C-519A-4CB4-B220-45CBE3297EAA at cern.ch]
>
>
>
> _______________________________________________
> Rivet mailing list
> Rivet at projects.hepforge.org
> https://www.hepforge.org/lists/listinfo/rivet
>