Common Sample "D" skim
has the following filters
- Selection of muons (used for almost all filters below) : selectMuo = true
- certified muons with nseg > 0
- pt > 1.5 GeV/c
- Chi2 of local fit of muon >= 0
- N(SMT) hits > 1
- N(CFT) hits > 1
- B =>
muon + loose D*, D*->D0pi, D0->Kpi : selectBDstarMuFlag = true
- CS filter "SKIM_AA_B_DSTMU_LOOSE"
- muon
- as above and pt>2.5 GeV
- no other muons in the same jet
- muon is not from J/psi candidate
- D0
- pt(K)>0.7, pt(pi)>0.7
- K & pi : # SMT hits >1
- K & pi from the same Durham jet as muon and from the same
PV
- K has the same charge as muon, K & pi have opposite charges
- m(K,pi) mass window [1.3-2.2 GeV]
- cos (angle between track and D0) > 0.8
- D*
- slow pion : # SMT hits > 1, same PV and nothing else
- Delta m < 0.2 GeV
- 2.2 < m B < 5.5 GeV
- no lifetime cuts
- piece
of code that does it all
- B => muon
+ Ds, Ds -> phi pi : selectBDsMuFlag = true
- CS filter "SKIM_AA_B_DSMU"
- muon as above + nseg > 1 + ptot(mu) > 3 GeV
- 3 tracks with pt > 0.7 GeV and in the same jet as muon
- N(SMT) > 1 for each track
- N(CFT) > 1 for each track
- M(KKpi) < 2.3 GeV
- M(KK) < 1.07 GeV
- cosine of angle between Ds direction and Ds momentum in axial
plane > 0.85
- distance/error in axial plane for Ds > 3
- 1.5 < Mass(mu Ds) < 5.5
- chi2 of (mu Ds) vertex < 16
- if B-vertex is after Ds-vertex, distance/error between B and Ds
< 3
- if distance/error for B-vertex > 4, cosine of angle between
B direction and momentum > 0.95
- piece
of code that does it
- J/psi &
dimuon mass continuum : selectJPsiFlag = true
- CS filter "SKIM_AA_JPSI"
- two certified muons of opposite change
- pt > 1.0 GeV for each particle
- N(CFT) > 1 for each particle
- at least 1 muon with nseg == 3
- if nseg > 0, then pt > 1.5 GeV (i.e. allow pt < 1.5 GeV
only for nseg = 0 muons)
- for muon with nseg = 0
- nmtc() >= 0, see MuonParticle class
- CalEsig() > 0.015*CalNLayer(), see MuonParticle class
- chi2 of global muon fit < 25 for both particles
- M(mu mu) > 2.5 GeV
- if M(mu mu) > 3.6 GeV: (High di-muon mass selection)
- nseg > 1 for both muons
- pt > 2.5 GeV for both muons
- piece
of code that does it
- B => D*pi,
D*->D0pi,
D0->Kpi : selectBDstarHFlag = true
- CS filter "SKIM_AA_B_DSTH"
- muons as above and pt>2.5 GeV
- D0
- pt(K)>0.7, pt(pi)>0.7
- K & pi : # SMT hits >1
- K & pi from the same Durham jet and from the same PV
- K & pi have opposite charges
- m(K,pi) mass window [1.75-1.95 GeV]
- cos (angle between D0 direction and D0 momentum) > 0.9
- D*
- slow pion : # SMT hits > 1, same PV and nothing else
- Delta m < 0.2 GeV
- B
- pion : pt>0.7, # SMT hits > 1, same PV
- 4.5 < m B < 7 GeV
- B vertex chi^2 < 36
- no lifetime cuts
- piece
of code that does it
- B => muon
+ tight D0, D*->D0pi,
D0->Kpi : selectBD0MuFlag = true
- CS filter "SKIM_AA_B_D0MU"
- muon as above + nseg > 1 + ptot(mu) > 3 GeV
- 2 tracks of opposite charge with pt > 0.7 GeV and in the same
jet as muon
- N(SMT) > 1 for each track
- N(CFT) > 1 for each track
- K is selected according to the charge of muon
- 1.4 < Mass(Kpi) < 2.2
- IP significance > 2 for each track
- Chi2 of (Kpi) vertex < 9
- distance/error in axial plane > 3
- cosine of angle between direction of track and momentum of D0
> 0.8
- 2.0 < Mass(mu D0) < 5.2
- chi2 of (mu D0) vertex < 9
- if B-vertex is after D-vertex, distance/error between B and D
< 3
- see D0 note 4280, section 4 for details
- piece
of code that does it
note that each filter has a flag so selections in your code will be most
CPU time effective if you use this flag