CDF recent results Paolo Mastrandrea (INFN Roma) on behalf of the CDF Collaboration Società Italiana di Fisica - XCVII Congresso Nazionale - L'Aquila, 26-30 Settembre, 2011 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 1
CDF experiment Wide international collaboration (~600 physicists); Very rich physics program studying processes over ~10 orders of magnitude in cross-section: heavy flavour physics; properties of W and Z bosons; properties of the top quark; search for the Higgs boson; search of processes beyond the Standard Model; Very rich record of publications; A selection of recent results is presented in this talk; For a complete record: http://www-cdf.fnal.gov/physics/physics.html SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 2
Tevatron Initial luminosity record 4.3107 10 32 cm -2 s -1 3 May 2011 p-p collisions @ s = 1.96 TeV 6.28 km circumference 2 interaction point: CDF, DØ Initial Luminosity 43%+ design Integrated luminosity ~ 12 fb -1 delivered per experiment ~ 12 fb -1 (on tape ~ 10 fb -1 ) reached ~ 2 fb -1 per year running stable at high luminosity Presented results up to 8.6 fb -1 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 3
CDF detector Multipurpose detector; Large radius drift chamber (1.4m); 1.4T solenoid; Projective calorimeters; Muon chambers; Silicon Vertex Detector; SVT: online high precision tracking @ L2 based on original associative memory application. Muon system Had calorimeter EM calorimeter Solenoid Tracker Silicon Vertex Detector SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 4
CDF results Heavy flavour physics Properties of W and Z bosons Properties of the top quark Search of processes beyond the Standard Model Search for the Higgs boson SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 5
X b 0 observation 4.2 fb -1 X b 0 first observation; X b - first observation in this channel; Complete reconstruction of the full decay chain; Complex hadronic final states; No leptons for trigger; Events acquired with the displaced track trigger (SVT) Mass [MeV/c 2 ] X b 0 5796.7 ± 5.1 ± 1.4 X b - 5787.8 ± 5.0 ± 1.3 arxiv:1107.4015v1 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 6
B s /B 0 m + m - 7.0 fb -1 FCNC processes that can occur in the SM through higher order loop diagrams; Enanched NN signal-to-background discriminant (n N ); B 0 data are consistent with background expectations - world s most stringent upper limit on BR; B s 0 data are in excess of the background prediction with a p-value of 0.27% BR(B 0 mm) < 6.0 x 10-9 @ 95% CL 4.6 x 10-9 < BR(B s0 mm) < 3.9 x 10-8 @ 90% CL BR(B s0 mm) = (1.8 +1.1-0.9 ) x 10-8 arxiv:1107.2304 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 7
Charmless decays of neutral b mesons 6.1 fb -1 First evidence of B s0 p + p - (significance 3.7s); World's best limit on BR(B s0 K + K - ); Tests accuracy of effective model of strong interactions; Decay rates sensible to new physics; Hadronic trigger (SVT). BR(B s0 p + p - ) = (0.57 ± 0.15 (stat) ± 0.10 (syst)) x 10-6 CDF Public note 10498 0.05 x 10-6 < BR(B s0 K + K - ) < 0.46 x 10-6 @ 90% CL SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 8
Z+b 7.9 fb -1 Precise test of the QCD; Main background for ZH llbb search; Test/validation of MC generators; NN used to improve muon ID (30% gain); b fraction extracted by a fit to secondary vertex mass distribution; CDF Public note 10594 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 9
ZZ 4l 6.1 fb -1 Precise test of the Electroweak sector; ZZ is the last diboson channel without a precise cross-section measurement; l ± = e ±, m ± ; Observed: 14 events; Expected: 10.4 signal + 0.26 background; Measured crosssection in agreement with NLO prediction of 1.4 pb s(pp ZZ) x BR(ZZ 4l) = 2.18 ± 0.63 (stat.) ± 0.30 (syst.) pb CDF Note 10480 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 10
ZZ llnn 5.9 fb -1 Cut based selection of ll+me T Background due mainly to detector resolution and jet mismeasurement; NN discriminant; NN output fitted with MC templates to extract ZZ component. s(pp ZZ) = 1.45 +0.45-0.42 (stat.) +0.41-0.30 (syst.) pb CDF Public note 10358 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 11
ZZ - Search for high-mass resonances 6.0 fb -1 4 events in ZZ 4l channel have invariant masses consistent with 327 GeV/c 2 ; Analysis in the ZZ llnn and ZZ lljj channels do not confirm a heavy resonance decaying into a pair of Z bosons; Upper limits set for 2 signal models. s(pp X ZZ) < 0.26 (0.28) pb @ 95 % CL CDF Public note 10603 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 12
WZ 7.1 fb -1 Crucial background for the H WW search in the associated production; Three-lepton + missing E T signature; NN discriminant; Fit to Z p T distribution to extract TGC limits. s(wz) = 3.9 +0.6-0.5 (stat) +0.6-0.4 (sys) pb s th (WZ) = 3.46 ± 0.21 pb CDF Public note 10176, 10595 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 13
W+jj 7.3 fb -1 Invariant mass distribution of jet pairs produced in association with a W; Analysis updated from 4.3pb -1 to 7.3pb -1 ; The significance of the excess increases from 3.2 to 4.1 standard deviations, consistent with expectation from the increase in the data sample size Phys.Rev.Lett.106:171801, http://www-cdf.fnal.gov/physics/ewk/2011/wjj/7_3.html SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 14
Evidence for WW/WZ ln+hf 7.5 fb -1 Ideal channel to validate Higgs analysis techniques; p-value 0.0012 3s excess; Multivariate discriminant based on the Support Vector Machine algorithm used to reduce QCD background. (s x BR) / (s x BR) SM = 1.085 +0.26-0.40 CDF Public note 10598 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 15
ZZ/ZW lljj 6.6 fb -1 Z reconstructed in charged leptons decay; A quark-gluon NN discriminant quantizes the spatial spread of the energy and track momenta contained within a jet; NN output used to correct the background modeling. s (ZZ+WZ) < 6.6 pb @ 95% CL (1.3 x s SM ) CDF Public note 10601 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 16
Forward backward asymmetry of top quark 5.3 fb -1 Combination of di-lepton and lepton plus jet measurements CDF Public note 10584 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 17
W polarization in Top dilepton events 5.1 fb -1 W boson polarizations are determined by a comparison of angular distribution of leptons in W rest-frame (cos q * ) with the templates corresponding to left-handed, right handed and longitudinal fractions exclusively; Model independent measurement. Observed SM f 0 0.71 +0.18-0.17 (stat.) ± 0.06 (syst.) 0.7 f + -0.07 ± 0.09 (stat.) ± 0.03 (syst.) 0.0 CDF Public note 10543 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 18
Top in hadronic t + jets 2.2 fb -1 First measurement of the top quark mass in the hadronic t + jets channel; NN removes most of the QCD background; Matrix element techniques used to measure top mass. M t = 172.7 ± 9.3 (stat.) ± 3.7 (syst.) GeV/c 2 s(tt) = 8.8 ± 3.3 (stat.) ± 2.7 (syst.) pb CDF Public note 10562 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 19
Top mass @ CDF 5.8 fb -1 CDF Public note 10444 M t = 172.7 ± 0.6 (stat.) ± 0.9 (syst.) GeV/c 2 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 20
m W [GeV] Top mass @ Tevatron 5.8 fb -1 m t [GeV] arxiv:1107.5255 M t = 173.2 ± 0.9 GeV/c 2 < 1 GeV/c 2 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 21
H gg 7.0 fb -1 Extended photon selection: Forward photons included; Additional central photon categories; new algorithm which selects central photons that have converted into an e + e - pair; NN to reject jet background; 33% improvement respect to 5.4 fb -1 result; Observed limit at 120 GeV/c 2 is <2s when trial factor is taken into account. CDF Public note 10485 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 22
WH lnbb 7.5 fb -1 Evenst selected with: 1 charged lepton; large missing E T ; 2 jets; 1 b-tagged jet; 3 taggers used (Sec. Vertex, JetProb, NNbased); NN discriminant to improve signal to background separation; Combination with independent analysis for events with 3 jets. CDF Public note 10596 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 23
H 4l 8.2 fb -1 4e, 4m and 2e2m final states; Some acceptance from ZH ZWW; 8 observed events, consistent with no events from Higgs boson decay. CDF Public note 10573 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 24
H WW * 8.2 fb -1 Search for SM H WW * decay in dilepton and tri-lepton plus missing E T final states; Increased signal acceptance: events with low dilepton invariant mass; consider also associated production with a W or a Z boson via vector boson fusion; 3 NN separately trained to distinguish signal from background in final states with 0, 1, 2 jets. Observed exclusion [ 156 ; 175 ] GeV/c 2 @ 95% CL CDF only CDF Public note 10599 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 25
Higgs @ CDF 8.2 fb -1 11 channels considered; ~70 measuremets combined. Observed exclusion [ 100.0 ; 104.5 ] GeV/c 2 [ 156.5 ; 173.7 ] GeV/c 2 @ 95% CL http://www-cdf.fnal.gov/physics/new/hdg/results_files/results/cdfcombeps2011/ SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 26
Higgs @ Tevatron 8.6 fb -1 CDF + D0 combination. Observed exclusion [ 100 ; 108 ] GeV/c 2 [ 156 ; 177 ] GeV/c 2 @ 95% CL arxiv:1107.5518v2 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 27
Higgs analyses perspectives CDF analyses are improving faster than just integrated luminosity gain for both low and high mass Higgs searches. SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 28
CDF Run II End of Data Taking - 30/9/2011 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 29
Conclusion CDF has deliverd a rich and exciting research program; Deep understanding of the experimental apparatus; Maturity of the analysis techniques; >20% more statistics still to be analysed; Pushing to get the best possible measurements delivered...... before the changeover! SIF SIF 2011, 2011, L'Aquila 26-30 26-30 September Paolo Mastrandrea 30
Backup x.x fb -1 reference SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 31
FCNC decay L b0 Lm + m - 6.8 fb -1 b smm processes occur in SM through higher order amplitudes; several BSM theories provide enanched rates for these decays; First observation of FCNC L b0 Lm + m - with a statistical significance of 5.8 s Differential branching ratio measurement for L b0 Lm + m - and B b0 fm + m - b smm process measured in several final states. resonant charmonium arxiv:1107.3753 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 32
FCNC decay B K (*) m + m - - angular distributions 6.8 fb -1 World most precise A FB measurement; Competitive with Bells's measurement; No discrepancy with SM predictions. resonant charmonium arxiv:1108.0695 F L longitudinal polarization fraction A (2) T transverse polarization asymmetry A FB A im foreward-backward asymmetry time-reversal-odd charge-and-parity asymmetry SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 33
Dark matter search with top 5.7 fb -1 Dark matter search at collider; Search for an exotic 4th generation quark T' decaying to t+x, where X is a dark matter candidate; m X 70 GeV/c 2 for m T' = 400 GeV/c 2 @ 95% CL arxiv:1107.3574v1 SIF 2011, L'Aquila 26-30 September Paolo Mastrandrea 34