1

The Topologies

For a B decay to a single cascade charm

D

B

IP • • • • lB

lD

ZVTOP vertex found furthest from IP contains the cleanest set of true B,D tracks

For SLD VXD2: in jets with this vertex topology the fate of MC true primary tracks was

77% in the Primary

16% in the Secondary

3% in the Tertiary

4% left Isolated

LCFI physics meeting 12/08/04

2

Highly boosted B kinematics: IP→B→D straight to ~1% (for Z0)

B,D vertex locations are not independent in 3D space

‘L/D’ construction based on this geometry

3

All non-primary vertices found must be n-prong with n ≥ 2

For IP→B→D decay chain can have 1-prong B or D decay

Can consider n-prong ZVTOP vertex as a Seed vertex

A track not directly associated with the Primary or Seed vertex, but with small T, is likely to come from B decay chain

4

L/D for non-Seed tracks passing T < 1mm

Monte Carlo Track

Origin

D Decay

IP

B Decay

VXD2 b-jets

Cut at L/D > 0.3 to attach tracks from B decay chain to SeedNB, red curve above is the most sensitive to detector resolution