1 / 15

Backup slides

Backup slides. e +. Z 0. e. e -. Z 0. Z 0 Z 0 production. Once  s > 2M Z ~ 182.4 GeV Pair production of Z 0 Z 0 via t-channel electron exchange. Other signatures in detector: e.g. 4 electrons (2e + ,2e - ). W -. W +. W-mass measurement. WW  qql  (2 constraints fit)

luz
Download Presentation

Backup slides

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. Backup slides

  2. e+ Z0 e e- Z0 Z0Z0 production • Once s > 2MZ ~ 182.4 GeV • Pair production of Z0Z0 via t-channel electron exchange. Other signatures in detector: e.g. 4 electrons (2e+,2e-)

  3. W- W+ W-mass measurement • WWqql(2 constraints fit) • Missing neutrino • WW  qqqq (5 constraints fit) • Ambiguity due to jet assignment (3 choices) Reconstruct the W mass directly in each WW event: • Form jets using particle 4-vectors • iterative clustering to 2- or 4-jets • Constrain total (E,p) to (s,0) • 4 constraints • obtain Ebeam from LEP • Constrain two W’s to have equal mass

  4. Higgs search results • OPAL 183-189 GeV data of last summer • Plot of the Higgs mass for Higgs candidates • Large contribution Z0Z0 events

  5. Much more difficult than at LEP Interaction rate: ~ 109 events/second Can record ~ 100 events/second (event size 1 MB) Trigger decision  ms  larger than interaction rate of 25 ns trigger YES save detector PIPELINE NO trash 109 evts/s Trigger Trigger rejection ~ 107 Store massive amount of data in pipelines while trigger performs calculations Trigger organized in three levels 102 evts/s

  6. High mass Higgs • HZZ l+l–jet jet • Need higher Branching fraction (also nn for the highest masses ~ 800 GeV/c2) • At the limit of statistics

  7. -- SM Higgs boson can be discovered at  5  with 10 fb-1/ experiment (nominally one year at 1033 cm-2 s-1) for mH  130 GeV -- Discovery faster for larger masses -- Whole mass range can be excluded at 95% CL after ~1 month of running at 1033 cm-2 s-1. However, it will take time to operate, understand, calibrate ATLAS and CMS

  8. SM Higgs: properties (II) • Relative couplings Higgs to fermions/bosons • Well predicted in Standard Model • Biggest uncertainty(5-10%): Luminosity • Relative couplings statistically limited

  9. SM Higgs: properties (III) • Self-coupling • From HH production • Cross sections are low • Relevant for MH<200 GeV • Need (unrealistically) high statistics, i.e. luminosities • for example, with 10x the statistics: measureslto 20-25% • Very hard at LHC • Linear e+e- TeV collider fb

  10. Symmetry Breaking in the SM (and beyond!) still not really understood Higgs missing; perhaps Tevatron, LHC designed to find it Physics at the LHC will be extremely rich SM Higgs (if there) in the pocket Turning to measurements of properties (couplings, etc.) Supersymmetry (if there) ditto Can perform numerous accurate measurements Large com energy: new thresholds TeV-scale gravity? Large extra dimensions? Black Hole production? The end of small-distance physics? And of course, compositeness, new bosons, excited quarks… There might be a few physics channels that could benefit from more luminosity… LHC++? We just need to build the machine and the experiments Summary

  11. Introduction Question: why LHC? Standard Model Matter and forces EW symmetry breaking Higgs particle Theoretical limits Current status of Higgs searches LEP collider LEP2 searches Higgs limits pp interactions Experimental techniques Kinematics Minimum bias The LHC machine Parameters Construction The ATLAS detector Construction NIKHEF participation What about Tevatron? Running status First physics results What with LHC if Tevatron finds the Higgs? –Break— SM Higgs At LHC & Tevatron Low mass region Intermediate+high mass The year 2007 Beyond the Higgs The future Contents

  12. All experiments • Combination of OPAL data with other three experiments; same c.m. energies: • No Higgs left

  13. B-tagging Neural net tag: Info from lifetime, Jet kinematics, Lepton tag (from bcl)

More Related