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Chris Parkes
1
LHC The Energy Frontier
Chris Parkes, GridPP 8, April 2012
ATLASATLAS
CMSCMSALICEALICE
LHCbLHCb
• Direct Production
• Simpler to interpret
• Probes masses
< E
Two Routes to New Physics
Chris Parkes
2
• Indirect Effects
• Model dependent interpretations
• Probes very high mass scales – virtual new particles
E=mc2
b
New particles
Contents: Selected new results• LHC Status
– 2011 data and 2012 expectation
• Heavy Ions (mainly ALICE)– Suppression/enhancement of particle rates
• Direct Production (mainly ATLAS/CMS)– The ‘H’ word– Electroweak / Top physics– SUSY
• Indirect effects (mainly LHCb)– Rare Decays– CP Violation - charm
Chris Parkes
3
Sources:Moriond E’weak,LHCC
Chris Parkes
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LHC: The New Improved Energy Frontier
Chris Parkes, GridPP 8, April 2012
75 ns 50 ns
2011 – recap
Increase number of bunches
Increase number of bunches
Reduce beam size
from injectors
Reduce beam size
from injectors
Squeeze further
Squeeze further
Increase bunch
intensity
Increase bunch
intensity
Initialcommissioning
Initialcommissioning
Scr
ubbi
ngS
crub
bing
Mike Lamont, LHCC
5
25 ns test
LHC Performance• LHC shows excellent performance• First two years of physics
• Recorded 40 pb-1 in 2010 at 7 TeV + Pb-Pb• Recorded 5 /1 fb-1 in 2011 at 7TeV + Pb-Pb
• 2012 – now restarted at 8 TeV
6
Power of Grid:All collected data reconstructed and many results on full samples
Aims for year: ATLAS/CMS – need max luminosity
many interactions per bunch crossing>15 fb-1 (3x 2011)
LHCb – need seconds !small number interactions per bunch
> 1.5fb-1
ALICE – heavy ionsFirst proton – lead collisions
2012 LHC schedule Q1/Q2
First Collisions
7
2012 LHC schedule Q3/Q4
Special runs
Special runs
Proton-lead
Proton-lead
Mike Lamont, LHCC
Followed by long shutdown to move to ~14 TeV8
Chris Parkes
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Heavy Metal FrontierLead Ions
Chris Parkes, GridPP 8, April 2012
Hadrons suppressed but photons shine !
Hadrons up to pT 100 GeV/c are suppressed
Photons up to ET 80 GeV are not
10
Chris Parkes
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LHC: The Energy FrontierDirect Production
Chris Parkes, GridPP 8, April 2012
Chris Parkes
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Higgs 1011) The last undiscovered particle in the Standard Model
– Higgs Mechanism gives masses to the W & Z
Chris Parkes
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Sta
ndar
d M
odel
Par
ticle
s
Higgs boson, spin=0
Electric charge 0
Higgs 1011) The last undiscovered particle in the Standard Model
– Higgs Mechanism gives masses to the W & Z
Chris Parkes
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Higgs boson
Mass = ?
2) The mass of the Higgs boson is not predicted
– The rate of production (cross-section) is predicted if you know the mass
Higgs 101
Chris Parkes
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3) The Higgs boson has lots of possible decay modes
– It prefers to decay to the heaviest thing available– Couples to mass
– But easier to find if low background rates– Best channel changes with Higgs mass
BR
Standard Model Higgs ?• Combination of many decay channels with FULL 2011 data sample
9
1) Black solid line below 1: excluded. Observed number of events less than would
have if the Higgs had that mass16
Standard Model Higgs ?• Zoom in on interesting region
2) Black dashed line : expected if no Higgs Black solid > black dashed = hint of a Higgs signal
17
Standard Model Higgs ?• Black line –
~probability of Higgs at that mass
• Sensitivity comes from ϒϒ channel
• ATLAS/CMS compatible
• New Tevatron result – also compatible
CMS Expected exclusion 114.5 - 543 GeVCMS Observed exclusion 127.5 - 600 GeV
18
Narrowing in on the Higgs
• Black line – From Indirect Effects: top mass and (new) Tevatron W mass
• Yellow blocks – excluded by direct searches
Chris Parkes
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Indirect Effects: Prediction is from Electroweak results-W mass and top mass
Electroweak
LHC status 20
Cross-sections of Electroweak processes
W and Z Production• W/Z cross-section ratio
– sensitive test of SM at LHC
• W Charge Asymmetry – changes sign in LHCb region: constraints on the low x
quark content of the protons at high q2.
€
σW + −σ
W −
σW + +σ
W −
ATLAS/CMS
21
Top Quark
Chris Parkes
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Top Quark
Chris Parkes
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Top quark spin correlations measured for 1st time
Top Quark
Chris Parkes
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Top quark mass approaching Tevatron
precision
25
Supersymmetry (SUSY) 101
Propose new symmetry of nature: SupersymmetrySpin ½ Fermions (quarks, leptons) spin 0 boson superpartnerSpin 1 Bosons spin ½ fermion superpartner
SUSY not an exact symmetryMass of SUSY particles ≠Mass of normal particles
Since none discovered yet
26
SUSY Motivation
4. SUSY provides a theoretical route to include gravity in “standard model”, and needed in string / M-theory
1/S
tren
gth
Log Energy GeV
1. SUSY allows unification of the forces 2. SUSY cancels divergences in SM
SUSY: theoretically beautiful and convenient – but is it true ?
3. Lightest SUSY particle (LSP) is candidate for dark matterMost models LSP is stable neutralino
SUSY + Exotics Searches SummarySUSY + Exotics Searches Summary
F. Cerutti - LNF-INFN 27
Optimal use of delivered data: Enlarge range of “experimental topologies”
look at as many “experimental topologies” as possibleThen make happy our friend theorists:
translate results in constraints to large variety of models
ATLAS – many analyses with FULL 2011 Luminosity
SUSY + Exotics Searches SummarySUSY + Exotics Searches Summary
F. Cerutti - LNF-INFN 28
Optimal use of delivered data: Enlarge range of “experimental topologies”
look at as many “experimental topologies” as possibleThen make happy our friend theorists:
translate results in constraints to large variety of models
Good Fraction of analyses updated with FULL 2011 Luminosity
SUSY is alive but she has a
headache
Chris Parkes
29
InteractionPoint
Muon System
Calorimeters
Tracking System
Vertex Locator
RICH Detectors
Beyond The Energy FrontierIndirect Effects
Chris Parkes, GridPP 8, April 2012
• Very rare decay – enhanced rate by new physics– LHCb rate < 4.5 x 10–9 (95%CL), CMS rate < 7.7 x 10–9 (95%CL), ATLAS < 22 x 10–9 (95%CL)
• New physics SUSY models with large tan β ~ ruled out
Chris Parkes
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green – allowed regionsblack/red – exclusion limits from CMSyellow - exclusion region from LHCb Bs→μμ result
SM prediction 3.2 x 10–9 Rare Decays: Bsμ+μ-
N. Mahmoudi
Most rare decay ever seen !• B+ → π+μ+ μ–
– First observation
• 25±6 events
• 5.2 σ significance
Chris Parkes
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B0 → K*0μ+μ–
- Constraining new physics up to 10TeV
Beyond the Energy Frontier
32
C P
CPParity InversionSpatialmirror
Charge InversionParticle-antiparticlemirror
Matter anti-matter (CP violation) 101
CP Violation Discoveries• Strange Quark System (Kaons)
– Discovery of CP Violation
• Beauty Quark systems (B)– CP violation theory in CKM matrix
– Also Bs, see next slide
• Charm System (D)– Is there CP Violation in Charm quarks ?– Predicted to be very small in SM– Good way of searching for New Physics ?
Chris Parkes
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6σ Asymmetry
Bs Matter Antimatter Asymmetry
Chris Parkes
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ArXiv:1202.6251v1, Feb 2012
B B
BsBs3.3σ
Asymmetry FIRST CP
CP Violation in Bs → J/ψϕ
• Powerful analysis to look for New Physics• Had been hints from TeVatron – but more precise LHC results give SM value
Chris Parkes
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1 fb-1, LHCb-CONF-2012-002
LHCb LHCc• LHCb was designed for b-quark studies
• But also ideal for studies of slightly shorter lived c quark, and 20 times more events
• CP Violation in charm sector (was) predicted to be very small in Standard Model < 0.1 %
• Bigger than this New Physics !
Chris Parkes
36
cc
e.g.
CP Violation: Problem 1 – Initial Condition• Technical Scale Drawing of LHC Collision
Chris Parkes
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Proton (Matter)
Proton (Matter)
• Start with matter and no antimatter• Ending with more matter than antimatter is not a surprise
Take difference in CP Violation between two decays
CP Violation: Problem 2 – Detector
Chris Parkes
38
• So if matter goes to a +ve particle and antimatter to –ve• Go to different parts of detector – can fake CP violation
1)Take difference in CP Violation between two decays
2)Reverse Magnetic Field Periodically
3)Choose a symmetric decay
+ve charge
-ve charge
• Particles bend in magnetic Field
Direct CP Violation in Charm
Chris Parkes
39
€
ACP (K +K −) =Γ(D→K +K −) − Γ(D→K +K −)
Γ(D→K +K −) + Γ(D→K +K −)
€
ACP (π +π −) =Γ(D→π +π −) − Γ(D→π +π −)
Γ(D→π +π −) + Γ(D→π +π −)
€
ARAW ( f ) = ACP ( f ) + ADetector( f ) + AProduction
What we measure
What we want
What we don’t want (1)
What we don’t want (2)
Chris Parkes
40
€
ACP (K +K −) =Γ(D→K +K −) − Γ(D→K +K −)
Γ(D→K +K −) + Γ(D→K +K −)
€
ACP (π +π −) =Γ(D→π +π −) − Γ(D→π +π −)
Γ(D→π +π −) + Γ(D→π +π −)
€
ARAW ( f ) = ACP ( f ) + ADetector( f ) + AProduction
What we measure
What we want
What we don’t want (1)
What we don’t want (2)
Symmetric Final State
Direct CP Violation in Charm
Chris Parkes
41
€
ACP (K +K −) =Γ(D→K +K −) − Γ(D→K +K −)
Γ(D→K +K −) + Γ(D→K +K −)
€
ACP (π +π −) =Γ(D→π +π −) − Γ(D→π +π −)
Γ(D→π +π −) + Γ(D→π +π −)
€
ARAW ( f ) = ACP ( f ) + ADetector( f ) + AProduction
What we measure
What we want
What we don’t want (1)
What we don’t want (2)
Symmetric Final StateMagnetic Field
Direct CP Violation in Charm
Chris Parkes
42
€
ΔACP = ACP (K +K −) − ACP (π +π −)
€
ARAW ( f ) = ACP ( f ) + ADetector( f ) + AProduction
What we measure
What we want
What we don’t want (1)
What we don’t want (2)
Symmetric Final StateMagnetic Field
Take Difference of final states
Direct CP Violation in Charm
Direct CP Violation in Charm
• High Statistics– 1.4M K+K-, 0.4M π+π-
Chris Parkes
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€
ΔACPPhys. Rev. Lett. 108, 111602 (2012), 12th March 2012
€
ΔACP = −0.82 ± 0.21(stat.) ± 0.11(syst.) %
Direct CP Violation in Charm
Chris Parkes
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€
ΔACP
€
ΔACP = −0.82 ± 0.21(stat.) ± 0.11(syst.) %
New Prelim Result, 28th February
€
ΔACP = −0.62 ± 0.21(stat.) ± 0.10(syst.) %
• Confirmation of Effect
• World Average 3.7 σ
Chris Parkes
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• First evidence of CP violation in charm sector
Interpretation: M. Gersabeck, S. Borghi, CP
http://arxiv.org/abs/1111.6515
Direct CP Violation in Charm
€
ΔACP
Average: Marco Gersabeck
New Physics ?• CP Violation in charm sector (was) predicted
to be very small in Standard Model < 0.1 %
• We measure 0.82±0.24% (on difference)
• New Physics ?
• Well maybe not…
Chris Parkes
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• Pb – Pb collisions– Particle suppression / enhancement in new state of matter
• Higgs:– Tantalising hints of SM Higgs around 125 GeV
• We will know this year
• SUSY:– No signs of her yet in direct production or rare decays
• Rare Decays:– Most rare decay ever seen
• CP Violation:– First evidence for CP violation in charm sector
• Compatible with SM ?
2011 Summary
Chris Parkes
47
• Pb – Pb collisions– Particle suppression / enhancement in new state of matter
• Higgs:– Tantalising hints of SM Higgs around 125 GeV
• We will know this year
• SUSY:– No signs of her yet in direct production or rare decays
• Rare Decays:– Most rare decay ever seen
• CP Violation:– First evidence for CP violation in charm sector
• Compatible with SM ?
2011 Summary
Chris Parkes
48
2012New World record energy
Expect lots more data for Grid to reconstruct
New Physics ?