Latest Collider Results Aidan Robson University of Glasgow IOP HEPP/APP, 30 March 2010

Aidan Robson Latest Collider Results 2 Aidan Robson

Latest Collider Results 3 Aidan Robson

HERA Aidan Robson Latest Collider Results 4 p e q l

DIS cross-sections Aidan Robson Latest Collider Results 5 JHEP 1001:109 (2010) Newly published! UK! p e q e Z/  p e q W

DIS cross-sections Aidan Robson Latest Collider Results 6 Newly published! UK! p e q e Z/  p e q W H1 cal scale uncertainty ↓55% Zeus photoprod bck unc ↓65%

PDFs Aidan Robson Latest Collider Results 7 Tevatron y = LHC H g g p p  pp → H =  gg → H f g/p (x 1,Q=M H ) f g/p (x 2,Q=M H ) + …

HERAPDF Aidan Robson Latest Collider Results 8 Newly published! UK! JHEP 1001:109 (2010)

FLFL Aidan Robson Latest Collider Results 9 New! Not previously measured directly E p (GeV)√s (GeV)L (pb –1 )

More structure Aidan Robson Latest Collider Results 10 d  /dx (pb) d  /dE T  (pb/GeV) e q  e q  E T   (GeV) Charm Isolated photons x 10

Striking signatures 11 New! p  X e+e+ e+e+ e+e+ e  q e q’ W e l SM signal SM bck Total predicted Data All65±1023±388±1181 P T X >25GeV20±34±124±329 UK! JHEP 03 (2010) 035 JHEP 10 (2009) 013 Multileptons Lepton plus E T  ep →W = 1.06±0.16(stat)±0.07(sys) pb (SM: 1.26±0.19 pb)

W production in pp! Aidan Robson Latest Collider Results 12 longitudinal parity- violating spin asymmetry Next: more bins of  RHIC: Relativistic Heavy Ion Collider sea: u, d

Tevatron Aidan Robson Latest Collider Results 13   = 1.0  = 0.6  = 2.0 muon chambers D0  =2  = m tracker had cal hadronic cal EM cal had cal solenoid pre-radiatorshower max silicon E M cal  =1 CDF Fibre tracker to |  |<1.8 Calorimeter to |  |<4 Muon system to |  |<2 Drift chamber to |  |<1 Further tracking from Si Calorimeter to |  |<3 Muon system to |  |<1.5

WW Aidan Robson Latest Collider Results 14 Tev error improves from 62 to 49 MeV New! UK! m W : CDF: m W = ± 48 MeV/c 2 D0: m W = ± 43 MeV/c 2 Tev: m W = ± 31 MeV/c 2 (includes Run 1) LEP: m W = ± 33 MeV/c 2 Heading to CDF 25MeV/c 2 measurement

mtmt Aidan RobsonLatest Collider Results 15 Matrix element-based top mass measurement Lepton+jets with 4.8fb -1 NN for background discrimination Likelihood fit over variables sensitive to top mass Simultaneous constraint of jet energy scale using W in lepton+jets m t =172.8 ± 1.3 total GeV (0.7 stat 0.6 JES 0.8 sys ) More precise than CDF 2009! Expect 1GeV precision achievable New!

Indirect constraints Aidan Robson Latest Collider Results 16 estimated final precision

Aidan Robson Latest Collider Results 17 Jets W/Z Higgs Susy quark top bottom quark  m s =17.77 ± 0.10 ± 0.07 dibosons

Single top Aidan Robson 18 Single top observed New! u W l g b b b t W d u W l b b t W d t-channel s-channel t-channel cross section [pb] s-channel cross section [pb]

19 ZZ seen in 4 lepton at 5.7σ All now observed! q q’ W/Z/  W/Z W/Z/  Dibosons photon E T (GeV) events Z Z Z    non-SM h 3, ZZ  |h 3 | < 0.037, |h 4 | < (  =1.2TeV) h 3, Z  SM non-SM W  Z   WW tt WZ t ZZ H → WW

Aidan Robson 20 q q’ W/Z H H t,b g g q q’ H W/Z SM Higgs searches m H /GeV gg  H qq  WH qq  qqH qq  ZH Br Latest Collider Results  / fb

ZH → bb Aidan Robson Latest Collider Results 21 cut at 0.6 removes 95% of the QCD background, 65% of the non-QCD background, and keeps 70% of signal most difficult final state among most sensitive channels New! UK! q q’ Z Z H b b

ZH → bb Aidan Robson 22 EWK and jets control regions Exp 4.6xSM Obs 3.7xSM Observe VZ with Z → bb? PRL (2010) New! UK!

WH → l bb Aidan Robson Latest Collider Results 23 Results at mH = 115GeV: 95%CL Limits/SM World’s most sensitive low-mass Higgs search q q’ W W H b b l Key issue: estimating W+bb background Shape from MC with normalization from data control regions Matrix element analysis Higgs Events Exp. Limit Obs. Limit

Low mass Higgs searches Aidan Robson Latest Collider Results 24

Low mass Higgs searches Aidan Robson Latest Collider Results 25

H → WW 26 discriminating variables: kinematics of 2 leptons; variables describing event topology eg LR with ME; multivariate techniques H t,b g g l l W W analysis strategy: split analysis into orthogonal channels and optimise separately jet multiplicity: different background compositions ETET ETET ee ee 10 2 DY Wj W  tt WZ ZZ DY WW HWWx10 Data kinematics of two leptons variables describing event topology 26

H → WW Aidan Robson 27 >1 jet 1 jet tt 0 jet WW Hx10 New! UK! Jet multiplicity: different background contributions S:8 S:6 Wj W  tt WZ ZZ DY WW HWWx10 Data S:13 4.8fb –1

No channel too small! Aidan Robson Latest Collider Results 28 q q’ W+W+ W+W+ H q’ q l+l+ l+l+ l–l– W+W+ W–W– New! S:2.2 S:0.5 ZH S:0.7WH S:1.0 (1A+1B) UK! trilepton same-sign dilepton NN Output

H → WW Aidan Robson Latest Collider Results 29 Bkg uncertainty does not wash out signal D0: Expect 35 Signal Events CDF: Expect 32 Signal Events

Aidan Robson Latest Collider Results 30 High mass Higgs combination New! UK! PRL (2010) PRL (2010) PRL (2010) Exp 0.87xSM Obs 0.93xSM SM Higgs excluded: 163<m H <166 GeV

New CDF HWW Aidan Robson Latest Collider Results 31 New! UK! 4.8 → 5.3 fb -1 : 5% better from statistics Optimized e - selection Added Trileptons, Low M ll, VH, VBF for 0 Jet All together: 15% better! Improvements continue (  modes add a few %) Results at m H = 165GeV: 95%CL Limits/SM Exp eventsExp.Obs. Publication New

Tevatron projection Aidan Robson Latest Collider Results 32 End : Sep 2011? On tape: ~ 6 fb -1 per experiment Results shown today : 3-5 fb -1 Integrated luminosity (fb –1 )

Aidan Robson Latest Collider Results

Low mass projections Aidan Robson Latest Collider Results 34 equivalent luminosity gain charm discrimination30% improved b-tagging20% improved dijet mass resolution15% extra final states5–10% improved lepton id5–10% total : 1.4x in the limit (~ 2x in effective luminosity) Probability of 95% CL Exclusion Probability of 3  evidence

4 th generation Aidan Robson Latest Collider Results 35 H t,X g g Low-mass scenario: masses close to experimental limits m l4 =100GeV m 4 =80GeV m u4 =256GeV m d4 =128GeV

MSSM H →  Aidan Robson 36 Key issue: understanding  ID efficiency Large calibration samples: W for ID optimization Z for efficiency confirmation New! UK! Benchmark scenario UK! No Evidence for SUSY Higgs  sensitive at high tan  in future will include b  b , b  bbb tan  Cross section x Br 95%CL (pb) Latest Collider Results

Aidan Robson Latest Collider Results 37 arXiv: From Kyle Cranmer, Moriod QCD 10 e+e+ e–e– Z* Z H e,      nMSSM constraints from LEP a a

Ones to watch? 38  b jets.Br is factor 2 too large

Aidan Robson Latest Collider Results 39 All the other things I didn’t have time for: ♦ SUSY limits ♦ limits on new heavy bosons ♦ observations of new baryons ♦ new jet measurements ♦ measurements of  s ♦ diffraction …

Outlook Aidan Robson Latest Collider Results 40 ♦ Strong physics programs with UK people at the centre. ♦ Legacy results still coming from HERA ♦ Many of the primary Tevatron goals have been achieved – and now we are focused on Higgs physics ♦ Themes: complex analyses, eg taus; combinations ♦ SUSY under pressure! ♦ Higgs within reach! – remarkable times. Thanks to Gavin Davies, Paul Newman, Katie Oliver and Matthew Wing for input.