1. Chant tracks for Analysis Apr/2003@Ishigaki O.Sato

2. All Chant 1 ST Prvt tracks are stored in DB @ NAGOYA. So we can analyze netscan data by Chant tracks But.. We knew sometimes very huge number of Tracks belonging to A vertex. And sometimes vertex is not only one but many.. Only 1 st Prvt tracks is enough or not.. This time.. Impact Parameter to NETSCAN reconstructed 1ry vertex was calculate and gives some hits about this.

3. Number of predicted tracks in a vertex Choral / Chant ChoralChant

4. Impact Parameter to NETSCANED 1ry vertex. Extrapolated Chant track NETSCAN reconstructed 1ry

5. Number of Chant Tracks /event (Prvt 1 st vertex tracks)

6. Just looking Impact parameter Large tail :: event bigger than 1 cm !!!

7. Impact parameter and number of Chant tracks Ntr<5 Sigma=433 μm Ntr 5 to 10 Sigma= 513 μm Ntr 10 to 30 Sigma =554 μm

8. Useful track fraction Assuming useful track for Netscan analyis :: Impact Parameter <2000 μm (4 sigma)

9. Summary Sometimes there are many track belong a PRVT. A part of them must not be 1ry track. Because quite big impact parameter to real 1ry vertex. In such case, TT matching by only angular matching is dangerous or no meaning. But also apply Impact parameter cut like IP <2000μm.