Two Higgs are better than one: Physics at the Super Large Hadron Collider and the implications for theCMS Silicon Tracker Tom Whyntie1st year PhD student, High Energy Physics GroupSupervisor: 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

The Large Hadron Collider

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

Why increase the luminosity?

• Statistics• Increase data rate precision

• Physics motivation1) Improve SM precision2) Improve “new physics” precision3) Extend discovery reach4) Sensitivity to rare processes

The question is: Where to look?

[6][7

][8]

Why increase the luminosity?

e.g. Trilinear coupling precision:• SLHC (mH = 150-200GeV): ~20% • SLHC (mH = 120GeV): ~50-80%• Linear Collider: ~20%

H

H

QH

(HH) ~10fb

[9][1

0][1

1][1

2][1

3][1

4]

Why upgrade to the SLHC?

• LHC discoveries will need probing• SLHC - increase precision & reach

• Present knowledge• Current infrastructure• Timeframe

The LHC environment1034 cm-2 s-1

The SLHC environment1035 cm-2 s-1

20x more interactions per bunch crossing

[7]

[15]

Detector Upgrade Issues

• Radiation tolerance• Services• Material budget• Data rates• TriggeringSolve and build in ~10 years!

[7]

[15]

Analysis102 HzHLT105 Hz

Level 1109 Hz

The CMS Trigger systemMuon chambers

ECAL HCAL

TrackerInnerOute

r

20x ?

Tracker informationà la HLT?

[7][16]

“Stacked Tracking”

1-2mm

(from interaction point)

High pT particleLow pT 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

1st year PGsYou – 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 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)

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)

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• 2000+ scientists• 155 institutes• 37 countries

The CMS Trigger systemMuon

chambers ECAL

HCAL

TrackerInnerOuter

SM Higgs decay mode branching ratios

Bran

chin

g ra

tio1

10-1

10-2

10-3 100 200 300 400 mH (GeV/c2)

Extracting the Higgs Self-coupling

[13]

Extracting the Higgs Self-coupling

[13]

Extracting the Higgs Self-coupling

Pleh

n et

. al.

Phys

Rev

D67

033

003

(200

3)

d/dm

vis (

fb/G

eV)

mvis (GeV)

Traditional Tracking

5-10cm

5-10cmReconstruct

track from hits

Siliconstrips/pixels

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.