B2A409-KFit-SmearedIPtube.py

#!/usr/bin/env python3
 
 
 
 
 
import basf2 as b2
from modularAnalysis import inputMdst
from modularAnalysis import reconstructDecay
from modularAnalysis import matchMCTruth
from vertex import kFit
from stdCharged import stdMu
from stdV0s import stdKshorts
from modularAnalysis import variablesToNtuple
import variables.collections as vc
 
# create path
my_path = b2.create_path()
 
# load input ROOT file
inputMdst(filename=b2.find_file('B02JpsiKs_Jpsi2mumu_Ks2pipi.root', 'examples', False),
          path=my_path)
 
# creates "mu+:all" ParticleList (and c.c.)
stdMu('all', path=my_path)
# creates "K_S0:merged" ParticleList
stdKshorts(path=my_path)
 
# reconstruct J/psi -> mu- mu+ decay
reconstructDecay('J/psi:mm -> mu-:all mu+:all', cut='3.05<M<3.15', path=my_path)
 
# reconstruct B0 -> J/psi K_S0 decay
# create two lists for comparison
reconstructDecay('B0:iptube -> J/psi:mm K_S0:merged', cut='5.27<Mbc<5.29 and abs(deltaE)<0.1', path=my_path)
reconstructDecay('B0:iptube20um -> J/psi:mm K_S0:merged', cut='5.27<Mbc<5.29 and abs(deltaE)<0.1', path=my_path)
 
# perform B0 vertex fit using only muons from J/psi
# fit one list with iptube constraint, the other with smeared iptube constraint.
kFit('B0:iptube', 0.0, 'vertex', constraint='iptube', decay_string='B0 -> [J/psi -> ^mu- ^mu+] K_S0', smearing=0.0, path=my_path)
kFit(
    'B0:iptube20um',
    0.0,
    'vertex',
    constraint='iptube',
    decay_string='B0 -> [J/psi -> ^mu- ^mu+] K_S0',
    smearing=0.002,
    path=my_path)
 
# perform MC matching (MC truth association)
matchMCTruth('B0:iptube', path=my_path)
matchMCTruth('B0:iptube20um', path=my_path)
 
# Select variables that we want to store to ntuple
B0_vars = vc.mc_truth + vc.vertex + vc.mc_vertex
 
# Saving variables to ntuple
output_file = 'B2A409-KFit-SmearedIPtube.root'
variablesToNtuple('B0:iptube', B0_vars,
                  filename=output_file, treename='B0tree_noSmear', path=my_path)
variablesToNtuple('B0:iptube20um', B0_vars,
                  filename=output_file, treename='B0tree_smear20um', path=my_path)
 
# Process the events
b2.process(my_path)
 
# print out the summary
print(b2.statistics)