def process(self, event):
'''Smear the beam energy.
The two incoming particle energies are smeared under
a Gaussian pdf of width sigma relative to the beam energy
All outgoing particles are then boosted to the new com
system
'''
genptcs = getattr(event, self.cfg_ana.gen_particles)
sigma = self.cfg_ana.sigma
f1 = random.gauss(1, sigma)
f2 = random.gauss(1, sigma)
beamptcs = [p for p in genptcs if p.status() == 4]
pprint.pprint(beamptcs)
assert(len(beamptcs) == 2)
def smear(ptc, factor):
e = ptc.p4().E() * factor
pz = math.sqrt(e ** 2 - ptc.m() ** 2)
if ptc.p4().Pz() < 0:
pz = -pz
ptc._tlv.SetPxPyPzE( ptc.p4().Px(),
ptc.p4().Py(),
pz,
e)
newcom = TLorentzVector()
for ptc, factor in zip(beamptcs, [f1, f2]):
smear(ptc, factor)
ptc.p4().Print()
print ptc.m()
newcom += ptc.p4()
print 'new com:'
newcom.Print()
boost = newcom.BoostVector()
stablep4_before = TLorentzVector()
stablep4 = TLorentzVector()
for p in genptcs:
if p in beamptcs:
continue
if p.status() == 1:
stablep4_before += p._tlv
# p._tlv.Boost(boost)
p._tlv.Boost(boost)
if p.status() == 1:
stablep4 += p._tlv
pprint.pprint(beamptcs)
print newcom.E(), newcom.Pz()
print stablep4.E(), stablep4.Pz()
print stablep4_before.E(), stablep4_before.Pz()
boost.Print()
def process(self, event):
sqrts = Collider.SQRTS
mZ = 91.
pi = TLorentzVector(0, 0, 0, sqrts)
jets = getattr(event, self.cfg_ana.jets)
jets_rescaled = []
setattr(event, self.cfg_ana.output, jets_rescaled)
if len(jets) == 0:
return
sump4 = TLorentzVector()
for jet in jets:
sump4 += jet.p4()
# print jet
a = sump4.Mag2()
b = -pi * sump4 * 2.
c = pi.Mag2() - mZ**2
sqdelta = math.sqrt(b**2 - 4 * a * c)
xmin = (-b - sqdelta) / (2 * a)
xmax = (-b + sqdelta) / (2 * a)
scaling_factor = xmin
## this solution leads to negative missing energy,
## going for the physical one
## if abs(xmax-1) < abs(xmin-1):
## scaling_factor = xmax
# print xmin, xmax
# print scaling_factor
if self.cfg_ana.verbose:
pi.Print()
sump4.Print()
print a, b, xmin, xmax, scaling_factor
for jet in jets:
jet_rescaled = copy.deepcopy(jet)
jet_rescaled._tlv *= scaling_factor
jets_rescaled.append(jet_rescaled)
if self.cfg_ana.verbose:
print jet
print jet_rescaled
