1. Two Higgs are better than one: Physics at the Super Large Hadron Collider and the implications for the CMS Silicon Tracker Tom Whyntie 1 st year PhD student, High Energy Physics Group Supervisor: Professor Geoff Hall

2. Outline of the talk Why upgrade? Physics case Higgs self-coupling measurement? Upgrade challenges The CMS silicon tracker Tracker info in the level-1 Trigger? Questions at the end, please

3. The Large Hadron Collider

4. [1][2][3][4][5]

5. Why increase the luminosity? Statistics Increase data rate  precision Physics motivation 1) Improve SM precision 2) Improve “new physics” precision 3) Extend discovery reach 4) Sensitivity to rare processes The question is: Where to look? [6][7][8]

6. Why increase the luminosity? e.g. Trilinear coupling precision: SLHC ( m H = 150-200GeV ): ~20% SLHC ( m H = 120GeV ): ~50-80% Linear Collider: ~20%  (HH) ~10fb [9][10][11][12][13][14]

7. Why upgrade to the SLHC? LHC discoveries will need probing SLHC - increase precision & reach Present knowledge Current infrastructure Timeframe

8. The LHC environment 10 34 cm -2 s -1

9. The SLHC environment 10 35 cm -2 s -1 20x more interactions per bunch crossing [7] [15]

10. Detector Upgrade Issues Radiation tolerance Services Material budget Data rates Triggering Solve and build in ~10 years! [7] [15]

11. Analysis 10 2 Hz HLT 10 5 Hz Level 1 10 9 Hz The CMS Trigger system Muon chambers ECALHCAL Tracker Inner Outer 20x? Tracker information à la HLT? [7][16]

12. “Stacked Tracking” 1-2mm (from interaction point) High p T particle Low p T particle “Stacked” pixel layers PASSES FAILS J Jones, A Rose et al [17][18]

13. “Stacked Tracking” [16][18]

14. Conclusions SLHC needed Describe new physics Improve, extend Many technical challenges 20x more interactions pbx e.g. level 1 triggering R&D needed – now!

15. Thanks to: G Hall, A Nikitenko, A Rose 1 st year PGs You – for listening Any questions?

16. References [1] The LHC Study Group: The Large Hadron Collider: Conceptual Design, CERN/AC/95-05 (1995) [2] Branson, J. G. et al: High transverse momentum physics at the Large Hadron Collider: The ATLAS and CMS Collaborations, Eur. Phys. J. direct C4, N1 (2002) [3] Krasnikov, N. V. & Matveet, V. A: Search for new physics at LHC, Phys. Usp. 47, p643−670 (2004) [4] CMS Collaboration: The Compact Muon Solenoid Technical Proposal, CERN LHCC/94-38, LHCC/P1 (1994) [5] ATLAS Collaboration: ATLAS Technical Proposal, CERN LHCC/94-43 LHCC/P2 (1994) [6] Scandale, W: LHC luminosity and energy upgrade, TUXPA03, Proc. European Particle Accelerator Conference ’06 Edinburgh (2006) [7] CMS Collaboration: CMS Expression of Interest in the SLHC, CERN LHCC 2007-014, LHCC-G-131 (March 2007) [8] Gianotti, F. et al: Physics Potential and Experimental Challenges of the LHC Luminosity Upgrade, Eur. Phys. J. C 39, p293−333 (2005) [9] Glover, E. W. & van der Bij, J. J: Multi Higgs Boson Production via Gluon Fusion, CERN-TH-5022-88 (1988)

17. References [10] Plehn, T. et al: Pair production of neutral Higgs particles in gluon-gluon collisions, Nucl. Phys. B479, p46−64 (1996) [11] Kanemura, S. et al: New physics effect on the Higgs self-coupling, Phys. Lett. B558, p157−164 (2003) [12] Plehn, T. et al: Probing the Higgs self-coupling at hadron colliders using rare decays, Phys. Rev. D69, 053004 (2004) [13] Blondel, A. et al: Studies on the measurement of the SM Higgs self-couplings, ATL-PHYS-2002-029 (2002) [14] Castenier, C. et al: Higgs self coupling measurement in e+e− collisions at center-of-mass energy of 500 GeV, LC-PHSM-2000-061, hep-ex/0101028 (2001) [15] Hall, G, private communication [16] CMS Collaboration, CMS Data Acquisition Technical Design Report, CERN/LHCC/2002-26, CMS TDR 6.2 (2002) [17] Jones, J. et al: A Pixel Detector for Level-1 Triggering at SLHC, Proc. LECC 2005 Workshop, CERN Report CERN-2005-011, p130−134 (2005) [18] Jones, J. et al: Stacked Tracking for CMS at Super-LHC, Proc. LECC 2006Workshop, CERN-2007-001, p130−134 (2007)

18. Backup Slides

19. What are we looking for? Origin of mass? Higgs? Supersymmetry? GUTs? Extra dimensions?

20. The Compact Muon Solenoid (CMS) Mass: 12500T Cost: £250M Time: ~15 years 2000+ scientists 155 institutes 37 countries

21. The CMS Trigger system Muon chambers ECAL HCAL Tracker Inner Outer

22. SM Higgs decay mode branching ratios Branching ratio 1 10 -1 10 -2 10 -3 100 200 300 400 m H (GeV/c2)

23. Extracting the Higgs Self-coupling [13]

24. Extracting the Higgs Self-coupling [13]

25. Extracting the Higgs Self-coupling Plehn et. al. Phys Rev D67 033003 (2003) d  /dm vis (fb/GeV) m vis (GeV)

26. Traditional Tracking 5-10cm Reconstruct track from hits Silicon strips/pixels  pT pT

27. How do we upgrade for the SLHC? Handle 20x more interactions Requires extensive R&D e.g. triggering at CMS This needs to start now/continue Focus of my PhD Data from current detector L1 triggering with tracker info.