1. Search for Charged Higgs in the Decay of Top Quarks at D0

2. Motivation A lot of time will be devoted to Standard Model Higgs searches. Need to look beyond the SM MSSM h, H, H ±, A.

3. Previous Searches at D0 A search was done in the channel H ± τ ± ν –Counted events with hadronically decaying W. –Presence of a H ± would cause a drop in different channels (see Yvonne’s talk) Similarly, H ± cs was also investigated – Counted events with leptonically decaying W.

4. My Project So far I have been working on a method to improve the search for H ± cs.

5. My Project Charged Higgs has spin 0, W has spin 1. Should give rise to differences in kinematics of the event, manifesting in different distributions for certain variables. Feed these discriminating variables into a neural network. Additionally, the mass of the charged Higgs is unknown so we can use different masses, giving rise to further discriminants

6. Discriminating Variables - Angle between hadronically decaying boson and jet with 2 nd highest pt

7. Discriminating Variables

10. Invariant mass of non-b jets For 120 & 150 GeV Higgs: – pt of SM b jets is harder – ht2 & ht3, again SM is a little harder – Eta, possibly (need to look with more events)

11. Looking Ahead Short term – Need to find a variable that discriminates well for a charged Higgs of mass 80 GeV – Continue to implement the most up-to-date Monte Carlo simulations – Look at reco. events Long(er) term – Separate signal from background by combining variables with a neural network

12. Thanks Terry, Christian & Yvonne

13. Back up Link to B jets (old MC)