1. 20 Jan 2009SiD Benchmark Meeting1 Chargino / Neutralino Analysis Update Yiming Li University of Oxford

2. 20 Jan 2009 SiD Benchmark Meeting 2 Sample Status slaclepton IDLcfi package reference1264199- ch1 +0.5 GeV1294~ 60- neu1 +0.5 GeV1205-- neu2 +0.5 GeV1277-- SM background√√1023 * unit: files (with 1k events in each)

3. 20 Jan 2009 SiD Benchmark Meeting 3 Kinfit W mass shapes look slightly different after installing new version of marlinreco etc. It makes difference how to set initial jet invariant mass Energy spectrum shape improves after Kinfit The big tail of W energy is due to non all-hadronic events. => can be reduced by choosing W mass window.

4. 20 Jan 2009 SiD Benchmark Meeting 4 Blue : choosing the best combination Red : the same jet combination, after 1C Kinfit left: setting initial m(jet) to be the real reconstructed value right: setting initial jet invariant mass to be 0 (default)

5. 20 Jan 2009 SiD Benchmark Meeting 5 (left: initial jet mass: actual jet mass) (right: initial jet mass: 0) Green: W energy only choosing best combination Red: W energy after kinfit Black: W energy at MC level

6. 20 Jan 2009 SiD Benchmark Meeting 6 Black: inclusive Purple: full-hadronic channel W energy after 1C Kinfit. (Black: MC) Blue: no limit on reconstructed W mass Red: 50 ≤ m ≤ 100 GeV Red dash: full-hadronic channel, 50 ≤ m ≤ 100 GeV

7. 20 Jan 2009 SiD Benchmark Meeting 7 W energy spectrum with W mass constraint 50 ≤ m ≤ 100 GeV Green: only choosing best combination Red: after kinfit

8. 20 Jan 2009 SiD Benchmark Meeting 8 Kinfit (cont.) Indeed see improvement on energy distribution It also causes correlation between the 2 W energy … should be taken into account when calculating the error but non- trivial! (the correlation is not 1, as in the 2 W masses case) Attempt to apply more constraints  2C on the two W masses respectively M(1,2) = 80.4 GeV M(3,4) = 80.4 GeV

9. 20 Jan 2009 SiD Benchmark Meeting 9 Plan Comparison with SM background with proper normalization; Understand & implement template fitting