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~ 1/4 of the people who made CMS possible

The CMS Collaboration, consisting of 3381 scientists and engineers from 173 institutes in 40 countries, presents an update on the search for the SM Higgs boson. The analysis focuses on the decay channel H->ZZ->4leptons, with a zoom-in on the low mass region. Results show observed events, exclusion limits, background fit model studies, and an analysis of an excess. The conclusion expresses gratitude to the LHC team for delivering exceptional integrated luminosity, but also humorously mentions a mistake made.

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~ 1/4 of the people who made CMS possible

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  1. Update on the SM Higgs Search with CMS ~ 1/4 of the people who made CMS possible The CMS Collaboration 3381 scientists and engineers (including ~840 students) from 173 institutes in 40 countries

  2. HZZ4leptons

  3. Zoom in the low mass Final state: 4e4μ2e2μ Obs. events: 355 Exp. events: 1.7 3.3 4.5 50 < mZ1 < 120 GeV 12< mZ2 < 120 GeV 100 < m4l < 160 GeV/c2 Observed events: 13 Expected events: 9.5 ± 1.3

  4. H gg

  5. H gg: data and exclusion limits A lot of studies on the background fit model. Is the structure/shape of the observed limit due to the chosen background model? No – this has been shown to not be the case. 5xH(120GeV) Using 5th order polynomial fit to background: some loss in sensitivity but negligible bias.

  6. CLs for SM Higgs Preliminary 95 and 99%CL exclusion limits 95% CL: obs 127-600, exp:117-543 99% CL: obs 128-525, exp:125-500

  7. Anatomy of an excess: local and global p-values Maximum local significance 2.6s. LEE-corrected significance (full mass range: 110-600GeV)= 0.6s LEE-corrected significance (low mass range: 110-145GeV)= 1.9s The excess we see in the low mass region has a modest statistical significance and could be reasonably a fluctuation of the background.

  8. Anatomy of an excess: best fit s/ssm 124 GeV Fitted σ/σSM compatible with 1 in the full low mass range. Median value touching 1 at a mass of 124 GeV and below.

  9. Conclusion • Many thanks to the whole LHC team for having delivered to the experiments an integrated luminosity exceeding our most optimistic expectations.

  10. Conclusion Many thanks to the whole LHC team for having delivered to the experiments an integrated luminosity exceeding our most optimistic expectations. but …. you did a terrible mistake

  11. Conclusion Many thanks to the whole LHC team for having delivered to the experiments an integrated luminosity exceeding our most optimistic expectations. but …. you did a terrible mistake You took me very seriously when I asked you last year: “gimme five”

  12. Conclusion Many thanks to the whole LHC team for having delivered to the experiments an integrated luminosity exceeding our most optimistic expectations. but …. you did a terrible mistake You took me very seriously when I asked you last year: “gimme five” and now you have a problem for 2012 “gimme twenty!”

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