Download LHC sensitivity to almost all SM Higgs masses 2011-12

Department of Physics
LHC physics
Dr Alan J Barr
For the TeV-scale physics group
Oxford:
Synonymous with
subatomic physics
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Frederic Soddy (1877–1956)
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Dick Dalitz (1925-2006)
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“I used to know all the data; at one time I knew every
event…”
Denys Wilkinson (1922-)
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Transmutation: “The interpretation of Radium”
Creation of the Nuclear physics laboratory 1964
International cadre of Oxford-trained physicists
LHC Physics
22nd June 2011
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Oxford’s international standing
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Global experimental leadership in:
 Detectors
 Tracker
R&D
 Construction & upgrade
 Monte Carlo Simulation
 Triggering / selection algorithms
 Calibration
 Exploitation / analysis
Stellar
international
reputation
(Even before talking about accelerators & theory…)
LHC Physics
22nd June 2011
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Large Hadron Collider
LEP
[ CERN ]
Geneva
HERA
[ DESY ]
Hamburg
TEVATRON
[ FermiLab ]
Chicago
LHC
[ CERN ]
Geneva
Particles:
Electron
Positron
ElectronProton
ProtonAnti-proton
ProtonProton
Beam
energy/TeV
0.105
e: 0.030
p: 0.92
0.980
7.0
(current 3.5)
75
402
10,000
Luminsoity
100
(1030 cm-2 s-1)
Stored
energy
(magnets)
~ GJ
1 MJ melts 1.5 kg Cu
Stored
energy
(beam)
~ 100 MJ
LHC Physics
22nd June 2011
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The accelerator…
1232 x 14.3 m dipoles
Superconducting
Superfluid
Liquid Helium Cooled
LHC Physics
22nd June 2011
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ATLAS
Segment of
4π detector
LHC Physics
22nd June 2011
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Semiconductor Tracker…
Robotic
assembly of precision silicon tracker
2004  2005
LHC Physics
22nd June 2011
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LHC Physics
22nd June 2011
8
The LHCb spectrometer
4Tm
Dipole
Vertex
Locator
(Silicon)
RICH detectors
Tracking
Calorimeters
LHC Physics
Muon
System
22nd June 2011
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RICH1 Front-end electronics
Johan Fopma, Phil Sullivan & the electronics workshop team
PIXEL anodes
Kaptons
Level-0 board
LHC Physics
22nd June 2011
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RICH1 Mechanics
Mike Tacon & the workshop team
Design and constructed the
lower HPD mounting system
Designed the upper system
Designed the RICH gas
enclosure
2009:
Cosmic rays
Precision alignment
Calibrations
Data acquisition
Combined tests
LHC Physics
22nd June 2011
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March 2010: first collisions
LHC Physics
22nd June 2011
13
First B+ → J/ K+ candidate
5 April 2010, 01:30:09
LHC Physics
22nd June 2011
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LAST WEEK
2010  0.035 fb-1
Huge reach even then
LHC Physics
22nd June 2011
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The Standard Model
Fields (Maxwell,
Weak, Strong)
Fermions (Dirac…)
Masses &
potentials.
(Untested)
LHC Physics
22nd June 2011
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Sure things
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Strong interaction
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Weak interaction
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Higgs Sector or other EWSB
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Flavours 3rd generation quarks (t and b)
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CP violation
45 physics publications from ATLAS on last year’s beam data
LHC Physics
22nd June 2011
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Strong interactions
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Self-interacting force
carriers
 Perturbative regime
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Jets of hadrons
 Radiation from accelerated
colour
 Backgrounds to all other
searches
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Non-perturbative
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Quark-gluon plasma
 Nucleon structure
LHC Physics
22nd June 2011
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Dijets @ muliti-TeV
CM Energy = 4 TeV
Excited quarks
Quantum Black Holes
Contact interactions
LHC Physics
22nd June 2011
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Weak
interactions
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Masses and
couplings well
known
 Self-interactions
under study
 Cross-sections
diverge without
new physics
WW
ZZ
LHC Physics
22nd June 2011
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W charge asymmetry
Vector – Axial couplings (Chiral couplings)
 Probe proton structure (Parton distributions)
 Cancellation of systematic uncertainties
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LHC Physics
22nd June 2011
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Higgs sector – the model
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Field couples to mass
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Scalar potential
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Vacuum expectation value
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W, Z masses via Higgs/gauge interactions
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Fermion masses via Higgs/Yukawa coupling
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Field excitation = Higgs boson(s)
LHC sensitivity to almost all SM Higgs masses 2011-12
LHC Physics
22nd June 2011
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Higgs boson production and decay
Coupling  mass
 Production
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Gluon fusion
 Weak boson fusion
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Decay
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To heaviest
allowed states
LHC Physics
22nd June 2011
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Last week: full ATLAS search Higgs analysis of 2010 data
LHC Physics
22nd June 2011
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Higgs search status
LHC Physics
22nd June 2011
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LHC Physics
22nd June 2011
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3rd Generation: t and b
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Three generations needed for CP violation
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Nearly decoupled from first two generations
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Long lived b-quark hadrons
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Standard Model: top Higgs coupling ~unity
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Radiative corrections from top on mH
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Role in electroweak symmetry breaking?
LHC Physics
22nd June 2011
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LHC Physics
22nd June 2011
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Using quantum corrections
Over-constrain SM parameters
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For example:
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Tree and penguin-level
determinations of CKM angle 
Charmless charged two-body B
decays
Bs mixing phase s from
Bs → J/
Branching fraction of
Bs → +Angular distributions in
B0 → K*+Bs →  and other radiative decays
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Hunt for rare processes
LHC Physics
22nd June 2011
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Effect of Particle ID on  → K+ K
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Early 900 GeV data
Hard-ish RICH cut on each kaon track DLL(K-pi)>15
Example of CP violation measurement
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2010 data
Separate samples into B0 and B0 using particle ID
Raw asymmetries clearly visible in data: direct CP Violation > 3s
Central values consistent with expectations and previous
measurements
NB: corrections from production and detector asymmetry not yet
corrected for
CP violation
Bd0
Bs0
More speculative (perhaps?)…
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Further generations
Unification of forces
Supersymmetry
WIMPs
Compositeness / substructure
New gauge forces / particles
Strong gravity
Extra dimensions
Something else?
LHC Physics
22nd June 2011
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Supersymmetry
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Partner particles
Spin differ by ½
Stabilise mH
Dark Matter
candidates
“Missing”
momentum
Huge reach at LHC
LHC Physics
22nd June 2011
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Results
3 June 2011
25 Feb 2011
“Missing” momentum
Scalar sum of momentum
LHC Physics
22nd June 2011
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Interpretation...
ATLAS 0 lepton
G. Ross et al
CMS
T
2010 data  approach cosmologically interesting region
LHC Physics
22nd June 2011
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LHC and ATLAS
upgrade schedules
LHC
 Phase-0 Shutdown:
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End 2012-mid 2013
 Physics resumes 2014
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ATLAS
 Phase-0
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IBL installation
 Repairs/consolidation
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Phase-I shutdown
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End of 2017
 Physics resumes end of
of 2018
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Phase-II
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End of 2021
Phase-I shut down
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Muon small wheels
Mini-FCAL
L1 calo topological trigger
Calorimeter readout
NewPix
Phase-II
Tracker  ready on surface
end of 2020
 TDAQ
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LHC Physics
22nd June 2011
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Existing tracker
Unique Oxford capabilities
All Si-upgrade
LHC Physics
22nd June 2011
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Software
Operations
Hardware
Grid
Computing
Detector & Upgrade
LHC Physics
22nd June 2011
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AJB
EXTRA SLIDES
LHC Physics
22nd June 2011
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Semiconductor Tracker close-up
LHC Physics
22nd June 2011
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LHC Physics
22nd June 2011
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Four Detectors
<10> inelastic collisions @ 20 MHz crossing rate
Record ~100 events/s
1 MB per event
Micron-scale precision
LHCb
ATLAS
ALICE
CMS
LHC Physics
22nd June 2011
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Higgs  diphoton
LHC Physics
22nd June 2011
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December 2008
LHC Physics
22nd June 2011
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PDFs are determined in Deep Inelastic ScatteringSTRONG Oxford involvement in HERAPDFBut can be used to predict cross sections for the LHC.
Early LHC data, using 36pb-1, are well predicted using
HERAPDFs
CMS μ asymmetry
ATLAS jets
These data can also be input to the fit to reduce the uncertainties
The CMS muon
asymmetry data already
reduces the uncertainties
on the low-x u and dvalence PDFs
These improvements allow us to predict Standard Model cross sections with greater
certainty so that the signal/background for Beyond Standard Model physics is enhanced
Search for the ultra-rare decays B0s & B0d → +•
The upper limits on the branching ratios are BR(B0s → +-) < 5.6 x 10-8 and
BR(B0d → +-) < 1.5 x 10-8 at 95% confidence level.
•
•
Standard model expectations BR(B0s → +-) < 0.32 x 10-8 and
BR(B0d → +-)
< 0.01 x 10-8
Approacing the world’s best measurement already with 2010 data
B0s → J/ 
(Early 2011 data)
• Important for measurement of weak
mixing phase in Bs system
• Amazingly small background