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LHC The Energy Frontier
Chris Parkes, GridPP 8, April 2012 LHCb ATLAS CMS ALICE Chris Parkes
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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
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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
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LHC: The New Improved Energy Frontier
Chris Parkes, GridPP 8, April 2012 Chris Parkes
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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
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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
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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
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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
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Heavy Metal Frontier Lead Ions Chris Parkes, GridPP 8, April 2012
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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
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LHC: The Energy Frontier
Direct Production Chris Parkes, GridPP 8, April 2012 Chris Parkes
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Chris Parkes
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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
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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
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Higgs 101 It prefers to decay to the heaviest thing available
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
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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
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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
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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
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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
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Cross-sections of Electroweak processes
LHC status
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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
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Top Quark Chris Parkes
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correlations measured for 1st time
Top Quark Top quark spin correlations measured for 1st time Chris Parkes
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Top Quark Top quark mass approaching Tevatron precision Chris Parkes
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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
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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 ?
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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
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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
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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
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Rare Decays: Bsμ+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
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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
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Matter anti-matter (CP violation) 101
Charge Inversion Particle-antiparticle mirror P C Parity Inversion Spatial mirror CP
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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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Bs Matter Antimatter Asymmetry
ArXiv: v1, Feb 2012 6σ Asymmetry B B Bs Bs 3.3σ Asymmetry FIRST CP Chris Parkes
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Direct CP Violation in Charm
New Prelim Result, 28th February Confirmation of Effect World Average 3.7 σ Chris Parkes
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Direct CP Violation in Charm
Interpretation: M. Gersabeck, S. Borghi, CP Average: Marco Gersabeck First evidence of CP violation in charm sector Chris Parkes
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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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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
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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
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