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LHC The Energy Frontier

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

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LHC The Energy Frontier

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  1. LHC The Energy Frontier LHCb ATLAS CMS ALICE Chris Parkes, GridPP 8, April 2012 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. Mike Lamont, LHCC 2011 – recap Squeeze further 75 ns 50 ns Increase number of bunches 25 ns test Increase bunch intensity Scrubbing Reduce beam size from injectors Initial commissioning

  6. 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. 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 Chris Parkes

  10. Hadrons suppressed but photons shine ! 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. 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 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 BR • 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 ? • 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 ? • 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 114.5 - 543 GeV CMS Observed exclusion 127.5 - 600 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. Electroweak Cross-sections of Electroweak processes LHC status

  21. 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. ATLAS/CMS 21

  22. Top Quark Chris Parkes

  23. 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 ½fermion superpartner • SUSY not an exact symmetry • Mass of SUSY particles ≠Mass of normal particles • Since none discovered yet

  26. 4. SUSY provides a theoretical route to include gravity in “standard model”, and needed in string / M-theory SUSY Motivation 1/Strength Log Energy GeV 1. SUSY allows unification of the forces 2. SUSY cancels divergences in SM 3. Lightest SUSY particle (LSP) is candidate for dark matter Most models LSP is stable neutralino 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. Muon System Vertex Locator RICH Detectors Beyond The Energy Frontier Indirect Effects Interaction Point Tracking System Calorimeters Chris Parkes, GridPP 8, April 2012 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. BsMatter Antimatter Asymmetry ArXiv:1202.6251v1, Feb 2012 B B 6σ Asymmetry Bs Bs 3.3σ Asymmetry FIRST CP Chris Parkes

  35. 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 1 fb-1, LHCb-CONF-2012-002 Chris Parkes

  36. LHCbLHCc c • 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 • Particles bend in magnetic Field +ve charge -ve charge • 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 • High Statistics • 1.4M K+K-, 0.4M π+π- Phys. Rev. Lett. 108, 111602 (2012), 12th March 2012 Chris Parkes

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

  45. Direct CP Violation in Charm Interpretation: M. Gersabeck, S. Borghi, CP http://arxiv.org/abs/1111.6515 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 • 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 ? Chris Parkes

  48. 2011 Summary • 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 ? 2012 New World record energy Expect lots more data for Grid to reconstruct New Physics ? Chris Parkes

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