1. LHC The Energy Frontier
Chris Parkes, GridPP 8, April 2012
LHCb
ATLAS
CMS
ALICE
Chris Parkes

2. Two Routes to New Physics
Direct Production
Simpler to interpret
Probes masses
< E
Indirect Effects
Model dependent interpretations
Probes very high mass scales – virtual new particles
E=mc2 b
New particles
Chris Parkes

3. 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
Sources:
Moriond E’weak,
LHCC
Chris Parkes

4. LHC: The New Improved Energy Frontier
Chris Parkes, GridPP 8, April 2012
Chris Parkes

5. 2011 – recap Mike Lamont, LHCC 75 ns 50 ns Squeeze further
Increase number of bunches
25 ns test
Increase bunch intensity
Scrubbing
Reduce beam size from injectors
Initial
commissioning

6. All collected data reconstructed and many results on full samples
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
Power of Grid:
All collected data reconstructed and many results on full samples

7. 2012 LHC schedule Q1/Q2 First Collisions 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 ions
First proton – lead collisions

8. Followed by long shutdown to move to ~14 TeV
Mike Lamont, LHCC
2012 LHC schedule Q3/Q4
Proton-lead
Special runs
Followed by long shutdown to move to ~14 TeV

9. Heavy Metal Frontier Lead Ions Chris Parkes, GridPP 8, April 2012

10. Hadrons suppressed but photons shine !
Raa of hadrons includes 2011 data. First paper submitted with 2011 data included
Raa of photons: the latest paper accepted for publication ( this weekend)
Hadrons up to pT 100 GeV/c are suppressed Photons up to ET 80 GeV are not

11. LHC: The Energy Frontier
Direct Production
Chris Parkes, GridPP 8, April 2012
Chris Parkes

12. Chris Parkes

13. Standard Model Particles
Higgs 101
1) The last undiscovered particle in the Standard Model
Higgs Mechanism gives masses to the W & Z
Higgs boson,
spin=0
Electric charge 0
Standard Model Particles
Chris Parkes

14. Higgs 101 Higgs Mechanism gives masses to the W & Z
1) The last undiscovered particle in the Standard Model
Higgs Mechanism gives masses to the W & Z
2) The mass of the Higgs boson is not predicted
The rate of production (cross-section) is predicted if you know the mass
Higgs boson
Mass = ?
Chris Parkes

15. Higgs 101 It prefers to decay to the heaviest thing availableBR
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
Chris Parkes

16. Standard Model Higgs ? 1) Black solid line below 1: excluded.
Combination of many decay channels with FULL 2011 data sample
1) Black solid line below 1: excluded.
Observed number of events less than would
have if the Higgs had that mass 16

17. Standard Model Higgs ? 2) Black dashed line : expected if no Higgs
Zoom in on interesting region
2) Black dashed line : expected if no Higgs
Black solid > black dashed = hint of a Higgs signal 17

18. 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 GeV
CMS Observed exclusion GeV 18

19. Narrowing in on the Higgs
Black line – From Indirect Effects: top mass and (new) Tevatron W mass
Yellow blocks – excluded by direct searches
Indirect Effects: Prediction is from Electroweak results-
W mass and top mass
Chris Parkes

20. Cross-sections of Electroweak processes
LHC status

21. W and Z Production W/Z cross-section ratio W Charge Asymmetry
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.
ATLAS/CMS 21

22. Top Quark
Chris Parkes

23. correlations measured for 1st time
Top Quark
Top quark spin
correlations measured for 1st time
Chris Parkes

24. Top Quark
Top quark mass
approaching Tevatron
precision
Chris Parkes

25. Supersymmetry (SUSY) 101 Propose new symmetry of nature: Supersymmetry
Spin ½ Fermions (quarks, leptons)  spin 0 boson superpartner
Spin 1 Bosons  spin ½ fermion superpartner
SUSY not an exact symmetry
Mass of SUSY particles ≠Mass of normal particles
Since none discovered yet

26. SUSY Motivation 1. SUSY allows unification of the forces
2. SUSY cancels divergences in SM
1/Strength
Log Energy GeV
3. Lightest SUSY particle (LSP)
is candidate for dark matter
Most models LSP is stable
neutralino
4. SUSY provides a theoretical route to include gravity in “standard model”, and needed in string / M-theory
SUSY: theoretically beautiful and convenient – but is it true ?

27. SUSY + Exotics Searches Summary
ATLAS – many analyses with FULL 2011 Luminosity
Optimal use of delivered data: Enlarge range of “experimental topologies”
look at as many “experimental topologies” as possible
Then make happy our friend theorists:
translate results in constraints to large variety of models
F. Cerutti - LNF-INFN

28. SUSY + Exotics Searches Summary
Good Fraction of analyses updated with FULL 2011 Luminosity
SUSY is alive but she
has a
headache
Optimal use of delivered data: Enlarge range of “experimental topologies”
look at as many “experimental topologies” as possible
Then make happy our friend theorists:
translate results in constraints to large variety of models
F. Cerutti - LNF-INFN

29. Beyond The Energy Frontier
Indirect Effects
Chris Parkes, GridPP 8, April 2012
Interaction
Point
Muon System
Calorimeters
Tracking System
Vertex Locator
RICH Detectors
Chris Parkes

30. Rare Decays: Bsμ+μ-
SM prediction 3.2 x 10–9
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
green – allowed regions
black/red – exclusion limits from CMS
yellow - exclusion region from LHCb Bs→μμ result
N. Mahmoudi
Chris Parkes

31. Most rare decay ever seen !
B+ → π+μ+ μ–
First observation
25±6 events
5.2 σ significance
Beyond the Energy Frontier
B0 → K*0μ+μ–
- Constraining new physics up to 10TeV
Chris Parkes

32. Matter anti-matter (CP violation) 101
Charge Inversion
Particle-antiparticle
mirror P C
Parity Inversion
Spatial
mirror CP

33. 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

34. Bs Matter Antimatter Asymmetry
ArXiv: v1, Feb 2012 6σ
Asymmetry B B Bs Bs
3.3σ
Asymmetry
FIRST CP
Chris Parkes

35. CP Violation in Bs → J/ψϕ
1 fb-1, LHCb-CONF
Powerful analysis to look for New Physics
Had been hints from TeVatron – but more precise LHC results give SM value
Chris Parkes

36. 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 !
e.g.
Chris Parkes

37. CP Violation: Problem 1 – Initial Condition
Technical Scale Drawing of LHC Collision
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
Chris Parkes

38. CP Violation: Problem 2 – Detector
+ve charge
-ve charge
CP Violation: Problem 2 – Detector
Particles bend in magnetic Field
So if matter goes to a +ve particle and antimatter to –ve
Go to different parts of detector – can fake CP violation
Take difference in CP Violation between two decays
Reverse Magnetic Field Periodically
Choose a symmetric decay
Chris Parkes

39. Direct CP Violation in Charm
What we
measure
What we
want
What we
don’t want (1)
What we
don’t want (2)
Chris Parkes

40. Direct CP Violation in Charm
What we
measure
What we
want
What we
don’t want (1)
What we
don’t want (2)
Symmetric Final State
Chris Parkes

41. Direct CP Violation in Charm
What we
measure
What we
want
What we
don’t want (1)
What we
don’t want (2)
Symmetric Final State
Magnetic Field
Chris Parkes

42. Direct CP Violation in Charm
What we
measure
What we
want
What we
don’t want (1)
What we
don’t want (2)
Symmetric Final State
Magnetic Field
Take Difference of final states
Chris Parkes

43. Direct CP Violation in Charm
Phys. Rev. Lett. 108, (2012), 12th March 2012
High Statistics
1.4M K+K-, 0.4M π+π-
Chris Parkes

44. Direct CP Violation in Charm
New Prelim Result, 28th February
Confirmation of Effect
World Average 3.7 σ
Chris Parkes

45. Direct CP Violation in Charm
Interpretation: M. Gersabeck, S. Borghi, CP
Average: Marco Gersabeck
First evidence of CP violation in charm sector
Chris Parkes

46. 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

47. 2011 Summary Pb – Pb collisions Higgs: SUSY: Rare Decays:
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. 2012 2011 Summary New World record energy
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
2012
New World record energy
Expect lots more data for Grid to reconstruct
New Physics ?
Chris Parkes