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updated version of transparencies shown in the meeting (3 rd Nov ’04)

updated version of transparencies shown in the meeting (3 rd Nov ’04) plots on p2, 3 are logarithmic in z (size of boxes corresponds to log of number of entries) plots show cases of correctly / wrongly reconstructed b-type (b or bbar)

stone-matthews
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updated version of transparencies shown in the meeting (3 rd Nov ’04)

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  1. updated version of transparencies shown in the meeting (3rd Nov ’04) • plots on p2, 3 are logarithmic in z (size of boxes corresponds to log of number of entries) • plots show cases of correctly / wrongly reconstructed b-type (b or bbar) • lower table on p4 contains numbers for wrong vertex charge • numbers for wrongly reconstructed b-type have been added on p5

  2. Can the maximum purity be increased? • optimised L/D cut value has • improved purity at high efficiency; • in low-efficiency range, purity did • not change • similarly, NN approach now gives • a flat purity, but maximum is still • unchanged • when forcing the D to decay at • its production point, improvement • is seen everywhere, and detector • dependencemuch more evident

  3. correct b, bbar identification wrong b, bbar identification Is relevant ZVTOP information being discarded? • region below the black line corresponds to jets with a B originating from a point • that fails the L/D cut • ZVTOP might still find vertices at those points, but that information is ignored at present

  4. 2 vertices found > 2 vertices found Compare wrong b,bbar jets with 2 and >2 vertices • when 2 vertices are found, B hadron origin agrees well with seed vertex decay length • for > 2 vertices, tracks from the B may be lost

  5. Details on vertices that are currently ignored numbers of tracks contained in jets with different types of topologies : 2 vertices > 2 vertices found by ZVTOP correct vertex charge 76841 (61%) 48658 (39%) wrong vertex charge 4724 (47%) 5126 (52%) for vertices with wrong vertex chargefind following percentages of tracks in vertices non-primary, but also not furthest from the IP: from IP from B from D (generator level) 3 vertex case: In secondary vertex: 1.3% 74.4% 23.1% 4 vertex case: In secondary vertex: 11.2% 65.3% 11.7% In tertiary vertex: 1.1 % 30.5% 61.5% note: these numbers are valid for vertices with wrong vertex charge (different from what is shown in the plots); equivalent numbers for cases with wrong b, bbar identification are shown on the following page

  6. Results for wrong b-type identification for vertices with b-type identificationfind following percentages of tracks in vertices non-primary, but also not furthest from the IP: from IP from B from D (generator level) 3 vertex case: In secondary vertex: 1.1 % 70.3 % 28.0 % 4 vertex case: In secondary vertex: 12.6 % 66.7 % 13.8 % In tertiary vertex: 3.0 % 30.9 % 63.4 %

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