The LHC THE STORY SO FAR Alan Barr University of Oxford PASCOS, July 2011

Alan Barr LHC The Standard Model 4th July 2011 Fields (Maxwell, Weak, Strong) Fermions (Dirac…) Masses & potentials. (Untested) Page 2 + other terms?

Alan Barr LHC The accelerator… 1232 x 14.3 m dipoles Superconducting Superfluid (1.9K) Liquid Helium Cooled 4th July 2011 Page 3 7 TeV CM energy  14 TeV ~1 GJ Magnetic Energy ~100 MJ Beam Energy 7 TeV CM energy  14 TeV ~1 GJ Magnetic Energy ~100 MJ Beam Energy 1 MJ melts 1.5 kg Cu

Alan Barr LHC Alan Barr LHC CMS LHCb ATLAS ALICE 2 x general-purpose experiments energy, momentum, identification controlled environment ~ 10 9 collision / second ~ decade of operation

Alan Barr LHC Page 5 4th July 2011 ATLAS Segment of 4π detector

Alan Barr LHC A Slice through the CMS detector 4th July 2011 Page 6 ATLAS & CMS: excellent operational efficiency CMS

Alan Barr LHC Local Interest: ATLAS Semiconductor Tracker… 4th July 2011 Page 7 Cambridge: Silicon R&D, testing Robotic assembly

Alan Barr LHC 8 4th July 2011 A year is a long time at the LHC Commissioned bunch trains 50 ns bunch-crossing operation

Alan Barr LHC 4th July 2011 Page 9 PASCOS 2010  fb -1 1 fb -1 target

Alan Barr LHC Alan Barr LHC Sure TeV-scale  Strong interaction  Weak interaction  Higgs Sector or other Electroweak SB  Flavours 3 rd generation quarks (t and b)  CP violation 4th July 2011 ~ 100 physics publications on collision data from CMS + ATLAS Page 10

Alan Barr LHC Alan Barr LHC Strong interactions  Self-interacting force carriers  Perturbative regime  Jets of hadrons  Radiation from accelerated colour  Backgrounds to all other searches  Non-perturbative  Quark-gluon plasma  Nucleon structure 4th July 2011 Page 11 ATLAS

Alan Barr LHC 4th July 2011 Page 12 CMS-QCD Agreement over 10 decades NLO Monte Carlo DATA deconvolved Uncertainties in Jet Energy Scale understood

Alan Barr LHC muliti-TeV 4th July 2011 CM Energy = 4 TeV Page 13 ATLAS ATLAS-CONF

Alan Barr LHC Alan Barr LHC Strong interactions – papers  Inelastic cross section  Jet cross sections  Jet shapes  Dijet azimuthal decorrelations  Dijet resonances  Underlying event  Charged hadron distributions  Bose-Einstein correlations  Strong contact interactions  Event shapes 4th July 2011 Page 14

Alan Barr LHC Alan Barr LHC Weak interactions  Masses and couplings well known  Self-interactions under study  Cross-sections diverge without new physics 4th July 2011 ZZ WW Page 15

Alan Barr LHC Electroweak cross sections 4th July 2011 Page 16

Alan Barr LHC W + Jets Electroweak + strong radiation Background to many searches Test MC simulations 4th July 2011 Page 17 ATLAS-CONF

Alan Barr LHC After you understand the Z… 4th July 2011 Page 18 ATLAS-CONF Excludes SM-like Z’ M<1.41 TeV

Alan Barr LHC Alan Barr LHC Higgs sector – the model  Field couples to mass  Scalar potential  Vacuum expectation value  W, Z masses via Higgs/gauge interactions  Fermion masses via Higgs/Yukawa coupling  Field excitation = Higgs boson(s) 4th July 2011 LHC sensitivity to almost all SM Higgs masses Page 19

Alan Barr LHC Alan Barr LHC Higgs boson production and decay  Coupling  mass  Production  Gluon fusion  Weak boson fusion  Decay  To heaviest allowed states 4th July 2011 Page 20

Alan Barr LHC 4th July June: full ATLAS search Higgs analysis of 2010 data Page 21 arXiv:

Alan Barr LHC Higgs  WW (search) 4th July 2011 Page 22

Alan Barr LHC 4th July 2011 Higgs search status Page 23

Alan Barr LHC Higgs   (search) 4th July 2011 Page 24 CMS-PAS-HIG

Alan Barr LHC Alan Barr LHC 3 rd Generation: t and b  Three generations needed for CP violation  Nearly decoupled from first two generations  Long lived b-quark hadrons  Standard Model: top Higgs coupling ~unity  Radiative corrections from top on m H  Role in electroweak symmetry breaking? 4th July 2011 Page 25

Alan Barr LHC Alan Barr LHC Papers (flavour) 4th July 2011 Page 26 arXiv:

Alan Barr LHC 4th July 2011 Page 27 ATLAS-CONF

Alan Barr LHC Alan Barr LHC More speculative (perhaps?)…  Further generations  Unification of forces  Supersymmetry  WIMPs  Compositeness / substructure  New gauge forces / particles  Strong gravity  Extra dimensions  Something else? 4th July 2011 Page 28

Physics Beyond the Standard Model 29 New results with 2011 data

Alan Barr LHC Alan Barr LHC Supersymmetry  Partner particles  Spin differ by ½  Stabilise m H  Dark Matter candidates  “Missing” momentum  Big reach at LHC 4th July 2011 Page 30

Alan Barr LHC Alan Barr LHC Supersymmetry searches 4th July 2011 Page Feb 2011 “Missing” momentum Scalar sum of momentum arXiv: ATLAS-CONF

Alan Barr LHC Alan Barr LHC Interpretation  Simplified model  Squark, gluino, massless neutralino  Exclude m q = m g < 1.02 TeV  Degenerate points harder 4th July 2011 Page 32 ATLAS-CONF

Wider interpretation... 23/03/2011Alan Barr, University of Oxford33 Allanach, Khoo, Lester, Williams Cassel, Ghilencea, Kraml, Lessa, Ross Points sampled from fits to global data Global CMSSM fits Regions with low fine tuning ATLAS 0/1 lepton ATLAS-CONF CMS α T June’11 Jan’11  h H

Alan Barr LHC Alan Barr LHC Getting the results?  ATLAS  Public results: linklink  CMS  Public results: linklink  Recent conference  Physics at the LHC 2011, ; linklink  Upcoming new results:  EPS 2011, July; linklink 4th July 2011 Page 34

Alan Barr LHC Alan Barr LHC Conclusions  Excellent operation of LHC and detectors  > 1 fb -1  Remarkable degree of control  New Physics Searches leading the world  Supersymmetry / WIMPs  Resonances  Substructure  …  Sufficient data for Higgs search  Over wide range of SM cross-sections  Full range by end 2012? 4th July 2011 Page 35

Alan Barr LHC EXTRA SLIDES LHC PHYSICS 4th July 2011 Page 36

Alan Barr LHC 2011 Plans… 4th July 2011 Page 37

Alan Barr LHC Alan Barr LHC Detector & Upgrade Grid Operations Computing Software 4th July 2011 Page 38 Hardware

Alan Barr LHC 4th July 2011 Page 39

Alan Barr LHC Alan Barr LHC 4th July

Alan Barr LHC Alan Barr LHC 4th July 2011 Page 41

Alan Barr LHC Alan Barr LHC Large Hadron Collider 4th July MJ melts 1.5 kg Cu Page 42

Alan Barr LHC Alan Barr LHC W charge asymmetry  Vector – Axial couplings (Chiral couplings)  Probe proton structure (Parton distributions)  Cancellation of systematic uncertainties 4th July 2011 Page 43

Alan Barr LHC 4th July 2011 Page 44

Pileup The pileup in 2011 is on average =6 interactions per crossing Significantly higher than 2010 And than originally anticipated in early LHC running Tails up to 14 interactions per crossing Due to some bunches with much higher currents Causes challenge for physics analyses and software Detailed simulation models both the and the bunch train structure Reweighted according to data distribution Software performance significantly improved to accommodate Tier0 resources (reco time 11-13s/event) Physics performance reasonably unaffected Jet energy scale uncertainty temporarily increased for low p T jets 45

Summary of Electroweak Boson and Top Quark Cross Sections All measurements agree with SM expectation (so far) Measuring cross sections of ~10 pb 46

Alan Barr LHC Further search papers  Others  Monojets  e-mu resonances  Dilepton resonances  Leptoquarks  CHAMPS  Dimuons (contact)  W'  l   Z'  l l  Supersymmetry:  Squarks or gluinos  Lepton + jet + invis  Dilepton + invis  Same sign leptons + invis  Z + invis  b-jet(s) + invis  R-hadrons 4th July 2011 Page 47