[Rivet] correction on ATLAS_2011_I944826 routine

[Sercan Sen]

Hi Frank,

Maybe I can ask a follow-up question... if we
extend the cfs acceptance, this would also affect the nstable>2 cut
(which would now also count particles in the extended acceptance).
Would that be correct?

Right. "nstable" part should be in |\eta| < 2.5 . So, if we extend the rapidity acceptance in the CFS projection, then we should apply a rapidity cut in the "nstable" part.. you know, something like below.

      int n_stable = 0;
      foreach (const Particle& p, cfs.particles()) {
        const PdgId pid = abs(p.pdgId());
        const double eta = fabs(p.momentum().eta());
if (inRange(eta, -2.5, 2.5)) continue;
        if (pid == 11 || pid == 13 || pid == 211 || pid == 321 || pid == 2212) n_stable++;
      }

or we can keep the CFS projection as it is and another projection can be applied for the trigger requirement:  "ChargedFinalState  trigfs(-2.09, 3.86, 100*MeV);"

By the way, I don't know if we need 100*MeV for ATLAS MBTS requirement (this is applied in the current code) ? Probably, we don't need it but this should be checked by someone from ATLAS..

Cheers,
Sercan







On Oct 23, 2012, at 11:15 AM, Frank Siegert wrote:

Hi Sercan,

Thanks for noticing this inconsistency. I take it, you're familiar
with the analysis? Maybe I can ask a follow-up question... if we
extend the cfs acceptance, this would also affect the nstable>2 cut
(which would now also count particles in the extended acceptance).
Would that be correct? If so, I'll make the change in the cfs
constructor directly.

Cheers,
Frank

On 23 October 2012 11:08, Sercan Sen <Sercan.Sen at cern.ch<mailto:Sercan.Sen at cern.ch>> wrote:

Hello,

I think there is a small correction needed on ATLAS_2011_I944826 routine.

It applies charged final states projection for the particles in |\eta| <
2.5, however, search for the hits in MBTS rapidity region 2.09 < |\eta| <
3.84. see below.. In this case, trigger cut is limited to the
2.09<|\eta|<2.5.

     ChargedFinalState  cfs(-2.5, 2.5, 100*MeV);
     addProjection(cfs, "CFS");

     const ChargedFinalState& cfs =
applyProjection<ChargedFinalState>(event, "CFS");

     // ATLAS MBTS trigger requirement of at least one hit in either
hemisphere
     const ChargedFinalState& cfs =
applyProjection<ChargedFinalState>(event, "CFS");
     int n_mbts = 0;
     foreach (const Particle& p, cfs.particles()) {
       const double eta = fabs(p.momentum().eta());
       if (inRange(eta, 2.09, 3.84)) n_mbts++;
     }

     if (n_mbts < 1) {
       MSG_DEBUG("Failed trigger cut");
       vetoEvent;
     }

Cheers,
Sercan

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