Cross-sections, efficiencies and discovery plots
Last update 19 January 2006
Selection efficiency (DC1) for
all dielectrons (upper left), dielectrons coming from d dbar (upper right),
dielectrons coming from u ubar (lower left), dielectrons coming from s sbar (lower right)
as a function of their invariant mass in GeV
All simulated models (SSM, LR, psi, chi, eta, KK, DY alone) are summed up.
Selection efficiency (DC1) with various models shown separately for
dielectrons coming from d dbar (left),
dielectrons coming from u ubar (right)
as a function of their invariant mass in GeV
Detailed selection efficiency (DC1)
for dielectrons coming from u ubar as a function of their invariant mass in GeV
Sensitivity of the selection efficiency to PDF choice
for uubar events (left) and ddbar events (right)
Acceptance for 4 PDF sets superimposed:
Ratio of acceptances (3 PDF sets over reference PDF, i.e. CTEQ5L):
Five sigmas discovery potential of ATLAS in the dielectron channel,
for 100 pb-1 (left) and 100 fb-1 (right)
with respect to SSM cross-section * branching ratio.
The number of signal events is defined as the integrated number of events above 0.9 times the Z' mass.
The only background taken into account is the DY.
The selection efficiency is conservatively taken as the one for dielectrons coming from u ubar (see above),
which is lower than the efficiency for dielectrons coming from d dbar (because of a larger boost).
The significance used is S = S12 = sqrt(S+B) - sqrt(B),
as proposed by S.I.Bityukov and N.V.Krasnikov, in e.g. hep-ph/0204326
Implicit hypothesis: a peak is observed, so that the mass of the candidate resonance is known.
Nevertheless, no use is made here of the shape of the signal, the result is based only on event counting (hence a conservative result).
TeVatron (left) and LHC (right)SSM, psi,chi Z' cross section*BR(Z'->e+e-)
at generator (pythia) level, in fb, for sqrt(s')>0.8*M(Z'), as a function of M(Z')
Creation date: 11 January 2006