Changes between Version 43 and Version 44 of HowToAddSample

Timestamp:

Jan 6, 2017, 2:38:27 PM (7 years ago)

Author:

Clarence Wret

Comment:

--

HowToAddSample

@@ -260 +260 @@
 
 {{{
-  // Need to make sure there's a muon
-  if (event->NumFSParticle(13) == 0) return;
-}}}
-
-To then get the muon kinematics in the `FitEvent` we use `FitEvent::GetHMFSParticle(int pdg)` to get the '''H'''ighest'''M'''omentum'''F'''inal'''S'''tate'''Particle''', which return a `FitParticle` object. The implementation for the `FitParticle` is in `FitBase/FitParticle.cxx`. We can now access the ROOT object `TLorentzVector` which stores the kinematics for the muon. So to get the muon we do:
-
-{{{
-  // Get the muon
-  TLorentzVector Pmu  = event->GetHMFSParticle(13)->fP;
+// Need to make sure there's a muon
+if (event->NumFSParticle(13) == 0) return;
+}}}
+
+To then get the muon kinematics in the `FitEvent` we use `FitEvent::GetHMFSParticle(int pdg)` to get the '''H'''ighest'''M'''omentum'''F'''inal'''S'''tate particle, which return a `FitParticle` object. The implementation for `FitParticle` is in `FitBase/FitParticle.cxx`. We can now access the ROOT object `TLorentzVector` in the `FitParticle` which stores the kinematics for the muon. So after we know there's a muon in the event we get the muon by:
+
+{{{
+// Get the muon
+TLorentzVector Pmu  = event->GetHMFSParticle(13)->fP;
+}}}
+
+Now we just need the momentum of this `TLorentzVector`, which can simply be done by calling `TLorentzVector::Vect()::Mag()`, amongst others.
+
+However, we recommend using the `FitUtils` namespace to unify the implementations and minimize errors. The `FitUtils` namespace lives in `src/Utils/FitUtils.cxx`, in which we see the `double p(TLorentzVector)` function. 
+
+To get the muon momentum (in GeV) we do
+
+{{{
+double p_mu = FitUtils::p(Pmu);
+}}}
+
+and then to finally set the `Measurement1D` member which saves the dependent variable we do
+
+{{{
+fXVar = p_mu
+
+return;
 }}}
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