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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][
10
][1
1][
12
][1
3][
14
]
Why upgrade to the SLHC?
• LHC discoveries will need probing• SLHC - increase precision & reach
• Present knowledge• Current infrastructure• Timeframe
The LHC environment
1034 cm-2 s-11034 cm-2 s-1
The SLHC environment
1035 cm-2 s-11035 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
102 HzHLT
105 HzLevel 1
109 Hz
The CMS Trigger system
Muon chambers
ECAL HCAL
Tracker
Inner
Outer
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 system
Muon chambers ECAL
HCAL
Tracker
Inner
Outer
SM Higgs decay mode branching ratios
Bra
nch
ing r
ati
o1
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
Ple
hn e
t. a
l.Ph
ys
Rev D
67 0
330
03 (
20
03
)
d/dm
vis (
fb/G
eV)
mvis (GeV)
Traditional Tracking
5-10cm
5-10cm
Reconstruct 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.