enqq and mnqq event selection

Pre-Pre-Selection

• CLASS 16
• Anti-qq cut: missing energy E_mis> 0, missing momentum P_mis > 0, E_mis+P_mis > 35 GeV
• Anti-qqg cut: longitudinal missing momentum P_zmis < (s-M_z²)/(2E_CM)-27.5 GeV OR P_zmis+sqrt(E_mis²-P_tmis²) < (s-M_z²)/E_CM-6 GeV where P_tmiss is the transverse missing momentum.

Pre-Selection

• Number of good charged tracks N_trks > 4
• Anti radiative event cut: b_z·E_vis-P_zvis > 5 GeV where Evis and Pzvis are the visible energy and longitudinal momentum, respectively and b_z=(s-M_z²)/(s+M_z²)
• Searching for the lepton candidate track: the lepton candidate is the good track with the largest P·sin(q_lj/2) where P is the track momentum and q_lj is the angle between the charged track and the closest jet among those ones reconstructed with the other good charged tracks with y_cut=3·10^-4
• E_lcorr+E_mis > 30 GeV where E_lcorr is the lepton candidate energy, corrected for the bremsstrahlung energy loss if it is identified as electron.
• Lepton-id: the lepton candidate has to be identified as an electron or as a muon.

Selection

In addition to the cut at the preselection level a new cut has been introduced: 

• Number of good charged tracks N_trks > 6

The following variables are computed and used as input arguments for a discriminating function (NN or pdf based). The events are selected by applying a cut on the function output value

• Transverse momentum P_t
• Lepton momentum P_lcorr corrected for the bremsstrahlung energy loss if it is identified as an electron
• log(tan(q_ACL/2))+log(tan(q_AFL/2)) where the angles q_ACL q_AFL are defined as:
  • q_ACL: the maximum angle of a cone around the lepton candidate which includes less than 200 MeV of good charged track energy.
  •   q_AFL: the maximum angle of a cone around the lepton candidate which includes less than 5 GeV of energy flow object energy.

Details and practical advices about the discriminating functions and how to use them can be found here.

03/02/03