2008/02/22 CDF Top Flavor ( ) 2008/02/22 Introduction Top quark is the heaviest known fundamental particle. Is this large mass related to electroweak symmetry breaking? Relationship between m t, m W, and m H Top quark has very short lifetime Decay before hadronization Momentum and spin are transferred to decay products 2008/02/22 Tevatron Run II Proton-Antiproton Collider with CM energy of 1.96 TeV Peak luminosity: 2.9 cm -2 s -1 Delivered luminosity: > 3.5 fb -1 2008/02/22 CDF II Detector General Purpose solenoidal detector Efficiency: ~85% Recorded >2.9 fb -1 2008/02/22 Top Pair Production Top pair production through strong interaction ~85% ~15% 2008/02/22 Top Pair Production Cross Section Measured using many different techniques Good agreement Between measurements Between data and theory dileptonl+jetsall hadronic 2008/02/22 Forward Backward Asymmetry Forward-backward asymmetry arises from interference between LO and higher order diagrams (NLO Theory: A fb = 0.040.01)(NLO Theory: A fb = 0.040.07) Lab (ppbar-rest) frame ttbar (parton) rest frame 1.9 fb -1 2008/02/22 ttbar Production Mechanism Measure fraction of gg vs. qq top production SM prediction: ~85% qq, ~15% gg Large theoretical uncertainty (~10%) Two complementary approaches NN with production and decay kinematics Track multiplicity distributions Combine two methods: ~6% improvement 1 fb -1 2008/02/22 ttbar Differential Cross Section Measure d /dM tt and test consistency with SM Spectrum is sensitive to many BSM resonances (Z , coloron, etc.) ttbar invariant mass is reconstructed for l+jets events Subtract background and correct the distribution using a regularized unfolding technique Data is consistent with SM p-value = fb -1 2008/02/22 Search for Massive Gluon Search for heavy gluon-like particle, G ttbar (color-octet model, etc.) 3 parameters Mass(M), Width( ), coupling( ) Event-by-event ttbar invariant mass reconstruction for l+jets with a Matrix Element technique (DLM) Data is consistent with SM (