CERN — The European Laboratory for Particle Physics

E-mail to: sb.talks@cern.ch


Integrated luminosity

 2011: 1.0 fb-1 
2012: 2.0 fb-1
2015: 0.30 fb-1
2016: 1.6 fb-1
2017: 1.7 fb-1
2018: 2.1 fb-1

Geometrical acceptance

 pseudorapidity: 2 < η < 5
angle: 10 < θ < 300 / 250 mrad (bending /non bending plane)

Resolutions

 momentum resolution: Δ p / p = 0.5 % at low momentum to 1.0% at 200 GeV/c
(see the detector performance paper for a plot)
ECAL resolution (nominal): 1 % + 10 %/ √(E[GeV])
impact parameter resolution: (15 +29/pT[GeV] ) μm
invariant mass resolution:
~8 MeV/c2 for B → J/ψ X decays with constraint on J/ψ mass
~22 MeV/c2 for two-body B decays
~100 MeV/c2 for Bs → φ γ, dominated by photon contribution
decay time resolution: ~45 fs for Bs → J/ψ φ and for Bs → Ds π

Efficiencies

 percentage of working detector channels: ~99 % for all sub-detectors
data taking efficiency:90 % (good for analyses: 99%)
trigger efficiencies:
~ 90 % for dimuon channels
~ 30 % for multi-body hadronic final states
track reconstruction efficiency: ~ 96 % for long tracks
Particle ID efficiency:
Electron ID ~ 90 % for ~ 5 % e→h mis-id probability
Kaon ID ~ 95 % for ~ 5 % π→K mis-id probability
Muon ID ~ 97 % for 1-3 % π→μ mis-id probability