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

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

The Large Hadron Collider

[1][2][3][4][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]

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

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

The LHC environment cm -2 s -1

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

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

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

“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]

“Stacked Tracking” [16][18]

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

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

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 , 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 (1988)

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, (2004) [13] Blondel, A. et al: Studies on the measurement of the SM Higgs self-couplings, ATL-PHYS (2002) [14] Castenier, C. et al: Higgs self coupling measurement in e+e− collisions at center-of-mass energy of 500 GeV, LC-PHSM , hep-ex/ (2001) [15] Hall, G, private communication [16] CMS Collaboration, CMS Data Acquisition Technical Design Report, CERN/LHCC/ , 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 , p130−134 (2005) [18] Jones, J. et al: Stacked Tracking for CMS at Super-LHC, Proc. LECC 2006Workshop, CERN , p130−134 (2007)

Backup Slides

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

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

The CMS Trigger system Muon chambers ECAL HCAL Tracker Inner Outer

SM Higgs decay mode branching ratios Branching ratio m H (GeV/c2)

Extracting the Higgs Self-coupling [13]

Extracting the Higgs Self-coupling [13]

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

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

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.