[Rivet] thrustMinor returns zero while calculating transverse thrust

[Deepak Kar]

Hi,

We are trying to finalize the Rivet analysis for arXiv:1207.6915
(ATLAS charged particle event shape).
A previous version of the data values is already in HepData, which
needs an update (more [lots were addded, systematics reduced following
referee review). Also a previous version of the analysis was written
(but never validated), but it seemed to work. However, with rivet
1.8.3, thrustMinor returns zero, however thrustMajor gives non-zero
values. The relevant part of the code:


 // Loop over particles
       foreach (const Particle& p, particles500) {
         num500 += 1;
         ptSum500 += p.momentum().pT()/GeV;

         // Transverse Thrust calculation requires p_z to be set to 0
         Vector3 mom = p.momentum().vector3();
         mom.setZ(0.0);
         momenta.push_back(mom);
       }


 // Actual Thrust calculation
      Thrust thrust;
      thrust.calc(momenta);

      const double T  = 1.0 - thrust.thrust();
      const double TM = thrust.thrustMinor();


We will convert the code to 2.0.x once it is fixed.

Thanks,
Deepak

-- 
Deepak Kar
ATLAS Research Associate
University of Glasgow, UK.
Homepage: http://ppewww.physics.gla.ac.uk/~dkar/


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