def __init__(self, leg1, leg2, pdgid, status=3, sort_by_pt=False, mass1=-1, mass2=-1):
'''
Parameters (stored as attributes):
leg1,2 : first and second leg.
pdgid : pdg code of the resonance
status : status code of the resonance
'''
if isinstance(leg1.physObj, ROOT.pat.PackedCandidate): leg1 = PhysicsObject(ROOT.pat.PackedCandidate(leg1.physObj))
if isinstance(leg2.physObj, ROOT.pat.PackedCandidate): leg2 = PhysicsObject(ROOT.pat.PackedCandidate(leg2.physObj))
if sort_by_pt:
self.leg1 = leg1 if leg1.pt() >= leg2.pt() else leg2
self.leg2 = leg2 if leg1.pt() >= leg2.pt() else leg1
else:
self.leg1 = leg1
self.leg2 = leg2
if mass1>0: self.leg1.setMass(mass1)
if mass2>0: self.leg2.setMass(mass2)
self._p4 = leg1.p4() + leg2.p4()
self._charge = leg1.charge() + leg2.charge()
self._pdgid = pdgid
self._status = status
class Kst(object):
'''
Builds a K*(892) candidate out of two tracks.
Assigns \pi and K mass hypothesis, find the assignment that returns the
invariant mass closer to the nominal K*(892) mass.
As an option, it can be required that the two tracks make a vertex.
'''
def __init__(self, tk1, tk2, requireVtx=False):
self.tk1_ = tk1
self.tk2_ = tk2
self.arbitrate()
self.vtx = None
self.vtxprob = -99.
if requireVtx:
# stuff I need to instantiate only once
self.vtxfit = VertexFitter()
# create a std::vector<reco::Track> to be passed to the fitter
self.tofit = ROOT.std.vector('reco::Track')()
# fill the vector
self.tofit.push_back(self.tk1_.physObj)
self.tofit.push_back(self.tk2_.physObj)
# fit the vertex and save the information
self.makeVtx_()
def makeVtx_(self):
# fit it!
svtree = self.vtxfit.Fit(self.tofit) # actual vertex fitting
# check that the vertex is good
if not svtree.get().isEmpty() and svtree.get().isValid():
svtree.movePointerToTheTop()
sv = svtree.currentDecayVertex().get()
recoSv = makeRecoVertex(
sv, kinVtxTrkSize=2) # need to do some gymastics
self.vtx = recoSv
self.vtxprob = ROOT.TMath.Prob(self.vtx.chi2(), int(self.vtx().ndof()))
def arbitrate(self):
pi1 = ROOT.Math.LorentzVector('<ROOT::Math::PxPyPzM4D<double> >')(
self.tk1_.px(), self.tk1_.py(), self.tk1_.pz(), m_pi_ch)
pi2 = ROOT.Math.LorentzVector('<ROOT::Math::PxPyPzM4D<double> >')(
self.tk2_.px(), self.tk2_.py(), self.tk2_.pz(), m_pi_ch)
k1 = ROOT.Math.LorentzVector('<ROOT::Math::PxPyPzM4D<double> >')(
self.tk1_.px(), self.tk1_.py(), self.tk1_.pz(), m_k_ch)
k2 = ROOT.Math.LorentzVector('<ROOT::Math::PxPyPzM4D<double> >')(
self.tk2_.px(), self.tk2_.py(), self.tk2_.pz(), m_k_ch)
# assign the mass hypotheses
if abs((pi1 + k2).mass() - m_k_st_zero) < abs((pi2 + k1).mass() -
m_k_st_zero):
self.pi_ = PhysicsObject(
ROOT.pat.PackedCandidate(self.tk1_.physObj))
self.k_ = PhysicsObject(ROOT.pat.PackedCandidate(
self.tk2_.physObj))
else:
self.pi_ = PhysicsObject(
ROOT.pat.PackedCandidate(self.tk2_.physObj))
self.k_ = PhysicsObject(ROOT.pat.PackedCandidate(
self.tk1_.physObj))
self.pi_.setMass(m_pi_ch)
self.k_.setMass(m_k_ch)
self.pi_.setPdgId(self.pi_.charge() * 211)
self.k_.setPdgId(self.k_.charge() * 321)
def charge(self):
return self.tk1_.charge() + self.tk2_.charge()
def pi(self):
return self.pi_
def k(self):
return self.k_
def p4(self):
return self.pi().p4() + self.k().p4()
def mass(self):
return self.p4().mass()
def eta(self):
return self.p4().eta()
def phi(self):
return self.p4().phi()
def e(self):
return self.p4().e()
def pt(self):
return self.p4().pt()
def p(self):
return math.sqrt(self.p4().px()**2 + self.p4().py()**2 +
self.p4().pz()**2)
def px(self):
return self.p4().px()
def py(self):
return self.p4().py()
def pz(self):
return self.p4().pz()
def pdgId():
# FIXME! get the correct pdgId based on the kaon an pion charges
return 313 if self.k().charge() > 0 else -313
