Tevatron Run II Chicago CDF TEVATRON D 0

Tevatron Run II Chicago CDF TEVATRON D 0 MAIN INJECTOR n n n The world's highest-energy particle collider. (Until LHC starts. ) Proton-antiproton collisions at sqrt(s) = 1. 96 Te. V Tevatron is performing really well n Peak luminosity: ~3. 5 1032 cm-2 s-1 2009/09/11 日本物理学会 2009年秋季大会 2

Datasets Summer 2009 shutdown Detector is stable and working well 5. 3 fb 1 6. 8 fb 1 5. 7 fb 1 Summer conference dataset. Require good runs 4. 4 -4. 8 fb 1 2009/09/11 日本物理学会 2009年秋季大会 3

13 Tevatron Prospects 12 11 10 8 7 6 5 4 3 2 Integrated luminosity (fb-1) 9 Running through FY 10 will yield 7 fb– 1 of data for analysis FY 11 start Running through FY 11 would yield 9 -10 fb– 1 of data for analysis FY 10 start 12. 0 fb-1 10. 0 fb-1 Highest Int. Lum Lowest Int. Lum Real data for FY 02 -FY 09 1 0 9 0 5 6 7 1 4 8 7 3 4 5 6 8 9 0 1 200 1/200 2/200 3/200 4/200 5/200 6/201 7/201 / 1 4/ 4/ 4/ time 4/ 4/ 4/ FY 04 10/ since 10/ 10/ 2009/09/11 日本物理学会 2009年秋季大会 4

CDF Collaboration North America 34 institutions Europe 21 institutions Asia 8 institutions The CDF Collaboration 15 countries 63 institutions 602 authors 2009/09/11 日本物理学会 2009年秋季大会 5

CDF II Detector n n n 8 layer silicon vertex detector 8 super layer drift chamber 1. 4 T solenoid Good particle identification (K, p) Central/Wall/Plug calorimeters Scintillator+drift chamber muon detectors 2009/09/11 日本物理学会 2009年秋季大会 6

Top Quark Physics quark-antiquark annihilation gluon-gluon fusion ~85% n ~15% Pair production n s(NLO) = 7. 4 +0. 5 -0. 7 pb (mt=172. 5 Ge. V) n Single production n n s-channel: s(NLO) = 0. 99 0. 07 pb t-channel: s(NLO) = 2. 15 0. 24 pb (mt=170 Ge. V) n Observed in March 2009. Categorize ttbar events into 3 decay types according to W decay mode (日本物理学会 第 64回年次大会 28 a. SE 08) 2009/09/11 日本物理学会 2009年秋季大会 7

ttbar Production Cross Section n Lepton+jets channel n Two different methods n n n Topological separation of signal and background via neural net Counting method with b-tagged events. Reduce luminosity systematics by normalizing to Z l+l rate 2009/09/11 日本物理学会 2009年秋季大会 8

ttbar Production Cross Section n Dilepton channel n n 2 leptons, large MET Require 1 b-tag n n Low background, lower statistics 2009/09/11 All-hadronic channel 6 jets, 1 or 2 b-tags Enormous QCD background n Train NN to improve S/B 日本物理学会 2009年秋季大会 9

ttbar Production Cross Section n CDF Combination n 2009/09/11 日本物理学会 2009年秋季大会 Precision of 6. 5% All channels are consistent with each other and with theory. Different methods to measure stt produce consistent results 10

ttbar+jet Cross Section n n Lepton+jets channel with b-tagging Check for NLO effects n (ETJET > 20 Ge. V) SM prediction: (S. Dittmaier, P. Uwer, and S. Weinzierl, Eur. Phys. J. C 59, 625 (2009)) 2009/09/11 日本物理学会 2009年秋季大会 11

Top Mass Measurement Using Matrix Element Method n n Matrix element analysis in l+jets Dominant mass systematic uncertainty typically due to a lack of understanding of the hadronic jet energy scale. n Simultaneously fit for top quark mass and shift in jet energy scale (JES). n n 2009/09/11 JES constrained by the hadronically decaying W qq' In situ calibration of the hadronic energy response 日本物理学会 2009年秋季大会 12

Top Mass Measurement Using Lepton p. T n n Lepton p. T spectrum dependent upon mtop. Advantages: n n n L+J Decouples from jet energy scale Might be a good technique for LHC DIL Disadvantages n n Requires large event samples Model dependence on ttbar production 2009/09/11 日本物理学会 2009年秋季大会 13

ttbar Spin Correlation Top quark is supposed to decay before losing polarization at its production (decays as a bare quark). But not yet confirmed experimentally. 。 照 Off-diagonal basis 参 を We can see correlations between flight directions of decay products. ク トー の 9 0 SA 細 p 1 1 SM は 詳 Signal Templates( =-1 1) or Background Templates 2009/09/11 (Mt = 175 Ge. V/c 2) 日本物理学会 2009年秋季大会 14

Forward-Backward Asymmetry n In L=3. 2 fb-1 data sample, observed an integral asymmetry: (Cf. 日本物理学会 第 64回年次大会 28 a. SE 06) n n Is “excess” spread out or localized in mass? More than 2 s excess from NLO prediction AFBpp = 5 1. 5% n n 2009/09/11 Dashed line are predictions for a integral AFB=19. 3%, as measured in data, with no mass dependence. Green solid line is for a NLL prediction (Almeida et al. ar. Xiv: 0805. 1885) with AFB linearly dependent on partonic invariant mass. 日本物理学会 2009年秋季大会 15

Search for ttbar Resonance n n n Some models predict ttbar bound states Top color assisted technicolor predicts leptophobic Z’ with strong 3 rd generation coupling Search in all hadronic channel Z’ with 1. 2% widt CDF (2. 8 fb 1): >805 Ge. V Z’ 2009/09/11 日本物理学会 2009年秋季大会 16

SM Higgs Search n Cross Section and Branching Ratio @Tevatron 2009/09/11 日本物理学会 2009年秋季大会 17

Higgs Search Channels ZH llbb H WW l l ZH bb ~6 months data Total WH l bb 2009/09/11 H WW lnln WH lnbb ZH nnbb ZH llbb 日本物理学会 2009年秋季大会 18

Low Mass Higgs: ZH llbb n n n Improve lepton acceptance Use neural network to correct jets for missing energy Use matrix elements and NN for event selection For m. H = 115 Ge. V/c 2 n Expected limit: 6. 8 s. SM n Observed limit: 5. 9 s. SM 2009/09/11 日本物理学会 2009年秋季大会 19

Low Mass Higgs: ZH/WH Search in MET+jets n n Good signal acceptance, complementary to other searches n Sensitive to: ZH bb, ZH llbb (mostly t), WH l bb (missed l) Dominant backgrounds: For m = 115 Ge. V/c 2 n n n QCD with fake MET due to cal resolution W/Z+jets, top, diboson b-tagging and neural net selection 2009/09/11 H n n Expected limit: 4. 2 s. SM Observed limit: 6. 1 s. SM 日本物理学会 2009年秋季大会 20

Low Mass Higgs: WH l bb n n n Bayesian NN selection New NN b-jet energy correction 4 b-tagging categories n For m. H = 115 Ge. V/c 2 n Expected limit: 4. 0 s. SM n Observed limit: 5. 3 s. SM New: NN b-tag 2009/09/11 日本物理学会 2009年秋季大会 21

High Mass Higgs: H WW* n n n Opposite sign leptons: H WW l l Same sign leptons for WH WWW Improved lepton acceptance Better lepton ID (likelihood) Better acceptance and improved sensitivity at low dilepton mass region Train NN for each category n OS 0/1/2+ jets, SS, OS low Mll 2009/09/11 日本物理学会 2009年秋季大会 For m. H = 165 Ge. V/c 2 n Expected limit: 1. 21 s. SM n Observed limit: 1. 23 s. SM 22

Combined Limit on Higgs n m. H = 115 Ge. V/c 2 n n n Expected limit: 2. 53 s. SM Observed limit: 3. 62 s. SM m. H = 160 Ge. V/c 2 n n Expected limit: 1. 29 s. SM Observed limit: 1. 24 s. SM 2009/09/11 日本物理学会 2009年秋季大会 23

Searches for New Physics n 2009/09/11 Mainly SUSY search results this time. 日本物理学会 2009年秋季大会 24

Sbottom Pair Production in MSSM n For 3 rd gen squarks, large mixing could lead to one of the stop and sbottom quarks to be light n n n Large cross section at Tevatron Signature: 2 high ET b-jets and MET QCD background (mistags/heavy flavor) estimated from untagged samples. 2009/09/11 日本物理学会 2009年秋季大会 ~b ~b b ~c ~c 0 0 b 25

Stop Decaying into Charm and Neutralino n n n If stop is light and stop chargino+b is kinematically forbidden, then stop neutralino+c might dominate. Signature: two charm jets + MET Developed a flavor separator to enhance charm separation 2009/09/11 日本物理学会 2009年秋季大会 26

Stop Search in Dilepton Channel n If the sneutrinos are lighter than stop, the dominant decay is into leptons. n n Signature similar to ttbar dileptons, but with soft leptons. Kinematics slightly different due to sneutrino mass. 2009/09/11 日本物理学会 2009年秋季大会 27

Stop Decaying into Bottom and Chargino n When stop is more massive than the lightest chargino, the dominant decay is very top-like: n The differences are: n n n Mass distribution of the stop Different “escaping particles” makes topology slightly different. Search in stop pair to dilepton channel. 2009/09/11 日本物理学会 2009年秋季大会 28

Chargino-Neutralino Production in Trilepton Mode n Trilepton channel in Dilepton chargino-neutralino production: “golden mode” n n 3 leptons + MET: very clean for hadron colliders Include isolated tracks for tau decays 2009/09/11 Trilepton 日本物理学会 2009年秋季大会 29

Chargino-Neutralino Limit in m. SUGRA n For chargino mass n n Expected limit: 156 Ge. V/c 2 Observed limit: 164 Ge. V/c 2 2009/09/11 日本物理学会 2009年秋季大会 30

GMSB Neutralino Search Using Photons n n Gauge-Mediated Supersymmetry Breaking (GMSB) models usually allow neutralino to decay in photon and gravitino (LSP). Search for neutralino pair production. n n Signature is: 2 photons and MET. Observed 0 event Expected 1. 2 ± 0. 3 ± 0. 2 Background rejection n n EMTiming (non-collision bkg) MET Resolution Model (QCD) 2009/09/11 日本物理学会 2009年秋季大会 31

Other BSM Searches 4 th Generation b’ in Same-Sign Dilepton Gaugino Pair Production in W+Z+MET R-Parity Violating Sneutrino Dijet+MET WW/WZ Resonance 2009/09/11 日本物理学会 2009年秋季大会 32

Summary n n n Tevatron is operating well. Better than ever! -1 is expected. n CDF is ready to run for FY 2011. Ldt ~ 12 fb Successful application of multivariate analysis techniques. Top quark properties are being measured more and more precisely. Mass precision is now less than 1%. n Top quark properties are consistent with SM so far. n Still improving the Higgs sensitivity. No signs of physics beyond SM, but search continues actively. n Stay tuned for interesting results from Tevatron in the near future! n n New top mass combination and new EW fit New Tevatron combined Higgs limit New search channels and updates on the search results 2009/09/11 日本物理学会 2009年秋季大会 33

Backup Slides 2009/09/11 日本物理学会 2009年秋季大会 34

Forward-Backward Asymmetry in ttbar Production n Charge asymmetry in ttbar production Forward-backward asymmetry n n LO QCD predicts 0 asymmetry NLO predicts Afb = (5 1. 5)% (O. Antuñano et al. , Phys. Rev. D 77, 014003(2008)) n n n + Interference between initial and final state radiation Interference between box diagram and Born process + DØ (0. 9 fb-1): Afbrec = 0. 12 0. 08 0. 01 (Reconstruction level, i. e. , no correction) 2009/09/11 日本物理学会 2009年秋季大会 35

Charm Tagging in Stop Search n Charm Hadron Analysis-Oriented Separator (CHAOS) n 2 D-output NN to distinguish flavor of jets: n n b jets, light jets, and c jets 22 input variables: Mvtx Qvtx Lxy/s. Lxy Npassed trk/Ngood trk p. Tgood trk/ETjet p. Tvtx/ETjet p. T 1 st/p. Tvtx p. T 2 nd/p. Tvtx <|d 0|>good trk <|d 0/sd 0|>good trk fjet hjet 2009/09/11 zt= p. Tpassed trk/ p. Tgood trk rvtx=p. Tvtx/ p. Tgood trk frac. of good trk w/ |d 0/sd 0|>1, 3, 5 signed d 0 of 1 st/2 nd trk signed d 0/sd 0 of 1 st/2 nd trk 日本物理学会 2009年秋季大会 36