Muon momentum smearing in CAFTree

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Detailed Description

The muon momentum can be smeared within CAF using a set of functions: two functions with predefined smearing parameters, and one function with user-defined inputs.

There are three methods in TMBMuon to smear muon momentum:

   void ActAsSmeared(Float_t * par, string name);
   void ActAsSmeard_pre();
   void ActAsSmeard_post();

The methods will overwrite the values returned by SmearedMC() and the momentum stored in TMBMuon (returned by Pt() ) with the new smeared values and will set the _best flag to kSmearedMC.

  ActAsSmeard(Float_t * par, string name)
  The array par controls the smearing as described below.
  
  ActAsSmeard_pre()
  The smearing parameters are preset to be identical to 
  the RPC parameters in D0Correct and are optimised to describe
  Data with run<2e5 (p17 old smearing parameters)
  
  ActAsSmeard_post()
  The smearing parameters are preset to describe
  Data with run>2e5 (p17 old smearing parameters)

The muons are smeared and scaled by a pt dependent Gaussian in q/pt either with:

  q/pt ->  S*q/pt + (A+B/pt)*rndnum

or with:

  q/pt ->  q/pt + sqrt(A^2+B^2*cosh(eta_cft)/pt^2)*rndnum

if the name passed into ActAsSmeared contains the string "zjpsi" (cf. D0Note 5444) Where rndnum=MCsmearingRand(); is the Gaussian random number already stored in TMBMuon. (If needed it can be set with TMBMuon::SetMCsmearingRand(ran) ).

The Parameters S,A,B are set separately in 4 regions

  region             offset
  ----------------------------
  SMT,Central           0
  SMT,Forward           1 
  noSMT,Central         2 
  noSMT,Forward         3
  

where SMT means that the track has >0 SMT hits and Forward means that that the Eta() and number of CFT hits are satisfying: fabs(Muon.Eta() ) > eta_cut || numCFTHits < ncft_cut

Where eta_cut and ncft_cut are set by the parameter array separately for SMT and noSMT, (defaults are eta_cut=1.6 ncft_cut=0).

  SMT:
  eta_cut=par[13];
  ncft_cut=par[12];
  noSMT:
  eta_cut=par[15];
  ncft_cut=par[14];
  

The parameters S,A,B are set by the par array using the offset of the table above as:

  
  A=par[offset];
  B=par[offset+4];
  S=par[offset+8];
 

Functions
void	TMBMuon::ActAsSmeared (Float_t *par, bool zjpsiparams=1)
	Function to Apply Muon Smearing.
void	TMBMuon::ActAsSmeared_pre ()
	Function to Apply Muon Smearing pre-shutdown 2004 parameter, code by Raimund Stroehmer.
void	TMBMuon::ActAsSmeared_post ()
	Function to Apply Muon Smearing post-shutdown 2004 parameter, code by Raimund Stroehmer.

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Function Documentation

void TMBMuon::ActAsSmeared (  Float_t *  par, bool  zjpsiparams = 1 )  [inherited]

Function to Apply Muon Smearing. Definition at line 365 of file TMBMuon.cpp. References TMBMuon::_best, TMBMuon::_smearedMC, TMBMuon::Central(), TMBMuon::CentralCorr(), TMBMuonType::charge(), TMBTrack::det_etaCFT(), TMBMuonType::err_eta(), TMBMuonType::err_phi(), TMBMuonType::err_pT(), TMBVector3::Eta(), TMBMuon::GetChargedTrack(), TMBMuon::hasCentral(), I_nosmt_eta_cft_cut_TMBMuon, I_nosmt_eta_cut_TMBMuon, I_nosmt_ncft_cut_TMBMuon, I_par_A_TMBMuon, I_par_B_TMBMuon, I_par_Bpt_TMBMuon, I_scale_TMBMuon, I_smt_eta_cft_cut_TMBMuon, I_smt_eta_cut_TMBMuon, I_smt_ncft_cut_TMBMuon, TMBMuon::kSmearedMC, TMBLorentzVector::M(), TMBMuon::MCsmearingRand(), TMBTrack::ncft(), TMBTrack::nsmt(), TMBVector3::Phi(), TMBVector3::Pt(), and TMBLorentzVector::SetPtEtaPhiM(). Referenced by TMBMuon::ActAsSmeared_post(), and TMBMuon::ActAsSmeared_pre().

void TMBMuon::ActAsSmeared_post (   )  [inherited]

Function to Apply Muon Smearing post-shutdown 2004 parameter, code by Raimund Stroehmer. Definition at line 462 of file TMBMuon.cpp. References TMBMuon::ActAsSmeared(), I_nosmt_eta_cft_cut_TMBMuon, I_nosmt_eta_cut_TMBMuon, I_nosmt_ncft_cut_TMBMuon, I_par_A_TMBMuon, I_par_B_TMBMuon, I_par_Bpt_TMBMuon, I_scale_TMBMuon, I_smt_eta_cft_cut_TMBMuon, I_smt_eta_cut_TMBMuon, I_smt_ncft_cut_TMBMuon, and npar_TMBMuon.

void TMBMuon::ActAsSmeared_pre (   )  [inherited]

Function to Apply Muon Smearing pre-shutdown 2004 parameter, code by Raimund Stroehmer. Definition at line 432 of file TMBMuon.cpp. References TMBMuon::ActAsSmeared(), I_nosmt_eta_cft_cut_TMBMuon, I_nosmt_eta_cut_TMBMuon, I_nosmt_ncft_cut_TMBMuon, I_par_A_TMBMuon, I_par_B_TMBMuon, I_par_Bpt_TMBMuon, I_scale_TMBMuon, I_smt_eta_cft_cut_TMBMuon, I_smt_eta_cut_TMBMuon, I_smt_ncft_cut_TMBMuon, and npar_TMBMuon.

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