1 / 10

Search for the Higgs boson in association with a Z boson

Search for the Higgs boson in association with a Z boson. Giulia Fanti. Michael Mulhearn Selcuk Cihangir. Physics motivation. Standard Model Missing piece Higgs mechanism electroweak symmetry breaking origin of mass implies existence of Higgs boson Higgs decays m H >135:

amena
Télécharger la présentation

Search for the Higgs boson in association with a Z boson

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Search for the Higgs boson in association with a Z boson Giulia Fanti Michael Mulhearn Selcuk Cihangir

  2. Physics motivation • Standard Model • Missing pieceHiggs mechanism • electroweak symmetry breaking • origin of mass • implies existence of Higgs boson • Higgs decays • mH>135: • mH<135: • Large background at Tevatron • ZH: possible production mechanism • LEP excluded mH<114 GeV/c2

  3. Detection • Electrons/positrons • Tracks in tracker • EM calorimeter • Jets • Energy in calorimeter • Tracks in the tracker • B-tagging • Silicon trackers • Displaced vertices • Muons/antimuons • Exterior muon chambers Image courtesy of Fermilab: http://www.fnal.gov/pub/now/live_events/explain_det_dzero.html

  4. Analysis Techniques • Preselection • Kinematic cuts, b-tagging • Start with mbb analysis • Single most discriminating variable • Multivariate techniques • Neural networks • Matrix element analysis • Standard Model: matrix elements • Transfer functions: jets, leptons • Hope to improve sensitivity

  5. mbb analysis: muon channel NN mbb/mjj values Calculated mbb/mjj values

  6. Further mbb analysis • Limit setting • Sensitivity to signal • SM amplification • Collie software • 95% confidence scaling factor: • Expected: 40.6 • Observed: 52.4

  7. Z-mass comparison NN zm values: Calculated zm values:

  8. Matrix-element analysis: electron transfer functions • Finite detector resolution • Double gaussian parametrization

  9. Future directions • Matrix element analysis • Technique developed on Run IIA data for muon channel • Muon channel • Understand kinematics of muon Run IIB data • Have transfer functions for jets, muons • Electron channel • Fitted electron transfer functions • Ready to apply ME analysis to both channels

  10. Acknowledgements • Mike Mulhearn • Selcuk Cihangir • Sabine Lammers • D0 collaboration and Fermilab • Department of Energy

More Related