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G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20111 ~ 1/4 of the people who made CMS possible The CMS Collaboration 3381 scientists and engineers.

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Presentation on theme: "G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20111 ~ 1/4 of the people who made CMS possible The CMS Collaboration 3381 scientists and engineers."— Presentation transcript:

1 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20111 ~ 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 Update on the SM Higgs Search with CMS

2 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20112 H  ZZ  4leptons

3 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20113 Zoom in the low mass 50 < m Z1 < 120 GeV 12 < m Z2 < 120 GeV 100 < m 4l < 160 GeV/c 2 Observed events: 13 Expected events: 9.5 ± 1.3 Final state: 4e 4μ 2e2μ Obs. events: 3 5 5 Exp. events: 1.7 3.3 4.5

4 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20114 H  

5 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20115 H   data and exclusion limits Using 5 th order polynomial fit to background: some loss in sensitivity but negligible bias. 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)

6 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20116 CLs for SM Higgs 95%CL:obs 127-600, exp:117-543 99% CL:obs 128-525, exp:125-500 Preliminary 95 and 99%CL exclusion limits

7 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20117 Anatomy of an excess: local and global p-values Maximum local significance 2.6 . LEE-corrected significance (full mass range: 110-600GeV)= 0.6  LEE-corrected significance (low mass range: 110-145GeV)= 1.9  The excess we see in the low mass region has a modest statistical significance and could be reasonably a fluctuation of the background.

8 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20118 Anatomy of an excess: best fit  /  sm Fitted σ/σ SM compatible with 1 in the full low mass range. Median value touching 1 at a mass of 124 GeV and below. 124 GeV

9 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 20119 Many thanks to the whole LHC team for having delivered to the experiments an integrated luminosity exceeding our most optimistic expectations. Conclusion

10 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 201110 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 Conclusion

11 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 201111 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” Conclusion

12 G. Tonelli, CERN/INFN/UNIPI HIGGS_CERN_SEMINAR December 13 201112 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!” Conclusion


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