Experiment CDF and participation of Slovakia Stanislav Tokr

Experiment CDF and participation of Slovakia Stanislav Tokár Univerzita Komenského Fakulta matematiky, fyziky a informatiky Katedra jadrovej fyziky a biofyziky Bratislava 2021 -12 -31 S. Tokár, UK FMFI 1

Tevatron at Fermilab 2021 -12 -31 S. Tokár, UK FMFI 2

CDF detektor/Tevatron Muon system calorimeters Up to |η|<3. 6 § CMP ; CMU |η|<0. 6 § CMX 0. 6<|η|<1. 0 y pseudorapidity Tracking system: § Silicon detector -> b tagging § COT : central outer tracker Eff. for charged particle tracks: § ~100% for |η|<1. 0 § ~40% for |η|≈ 2. 0 12/31/2021 q z x Excellent lepton ID: ~80% eff. for central electrons ~90% eff. for high p. T muons S. Tokár, CDF new results, 2008 3

Slovakia group activity at Tevatron 2006: Joint team of Kosice and Bratislava’s physicists joined to CDF experiment 1993: first contact of Kosice group with CDF (J. Antos via Sinica Univ. Taiwan) 2001: first contact of Bratislava group with CDF (S. Tokar via JINR Dubna) Kosice team: J. Antos, R. Lysak, M. , Zvada M. Bratislava team: S. Tokar, P. Bartos, P. Bednar, A. Brisuda, L. Lovas PHD thesis: Defended: R. Lysak(2007), P. Bednar(2008), L. Lovas (2009) Submitted: P. Bartos (April 2011) Master thesis: J. Novak, R. Lysak, L. Lovas 2021 -12 -31 S. Tokár, UK FMFI 4

Activities of Slovak teams q. Top quark properties: üForward –backward asymmetry in ttbar production üW boson helicity ütop quark charge üttbar spin correlations ütop quark mass in Dilepton channel (2 analysis) q. Higgs boson search: ü H-> WW q. Soft QCD üBose Einstein correlations qservice work: ü CDF Offline management üMuon efficiency calculation ü FNAL GRID management üJet energy scale calculations ü CDF Computing on GRID FARM in IEP 2021 -12 -31 S. Tokár, UK FMFI 5

Jet energy scale via gamma + jets events +jet events are used for jet calibration Excellent resolution of EM calorimeter used ü Photon with: p. T balance ü ü 2 nd jet p. T balance after all corrections Absolute and out-of-cone calibrations fb CABS 2021 -12 -31 photon p. T (Ge. V) S. Tokár, UK FMFI COOC 6

Top Quark Mass in Dilepton Channel Participation in 2 analyses ü Top quark is the heaviest particle of the SM ü Yukawa coupling is ~1 special role in EW symmetry breaking? üCan be used to infer Higgs mass via radiative corrections: üDilepton channel: independent measurement of top quark mass with low background (the cleanest channel) 2021 -12 -31 S. Tokár, UK FMFI 7

Top mass in DIL channel: templates ü Top quark mass measured in dilepton channel using a template method. ü Due to 2 neutrinos Mtop reconstruction from dilepton events is underconstrained fixed to solve event kinematics üThe sample is separated into b-tagged and non-tagged samples. For each event reconstructed assum. : using a cross-section constraint 2021 -12 -31 S. Tokár, UK FMFI 8

Top Quark mass in Di. L: neutrino weighting ØTight lepton and isolated track sample üTight lepton (ET>20 Ge. V), track lepton (p. T>20 Ge. V) ü 2 jets (ET > 20 Ge. V), MET > 20 Ge. V Ø PHI method for constraining the kinematics ü Assume φ1, φ2 of the neutrinos as known ü A 144 points grid is created in (0, π)x(0, π) ü 2. 9 fb-1 of data used for top mass ØFor each (φ1, φ2) is reconstructed ( 2 min) ØWeighted average of the 144 masses is performed üWeights depend on minimized 2 ü 1 reconstructed top mass per event Fitted top mass from 328 data events (2. 9 fb-1): 2021 -12 -31 S. Tokár, UK FMFI 9

SM Higgs boson search High mass search 2021 -12 -31 S. Tokár, UK FMFI 10

Higgs boson production and decay H boson production: ü Gluon fusion ü Vector boson fusion üAssociated production Low H mass WH→lvbb H→γγ ZH→ll(vv)bb tt. H→ttbb VH/VBF→bbjj H/VH/VBF→ττ+jets 2021 -12 -31 High H mass H → WW → l l → l had → l jj WH, ZH → WWW, ZWW S. Tokár, UK FMFI 11

Higgs boson: background Higgs boson: a small signal in a sea of background: QCD, W+jets, di-bosons, tt-bar, single top 2021 -12 -31 S. Tokár, UK FMFI 12

Tevatron SM Higgs limits-high mass Candidate events H → WW → l l , → l had , → l jj Selection for l l final states: ü 2 opposite-sign leptons: ET > 20 Ge. V (p. T > 20 Ge. V/c) for electrons (muons) ü Large missing ET: to for e -pairs) (reduced ü dilepton invariant mass: Mll > 16 Ge. V/c 2 üIndividually considered states with: jets, 1 jet, two jet and more jets no Expected background for 1 jet case and signal for m. H = 165 Ge. V/c 2 2021 -12 -31 S. Tokár, UK FMFI 13

Tevatron SM Higgs limits-high mass Neural network is trained for ü weighted combination of S and B ü 19 Higgs mass points treated ü 0 -jet analysis : 9 input variables No excess above background CDF (7. 1 fb-1) exclusion: expected: 159 – 168 Ge. V observed: 158 – 168 Ge. V 2021 -12 -31 S. Tokár, UK FMFI 14

Top Quark Charge Is the top quark really a SM particle? 2021 -12 -31 S. Tokár, UK FMFI 15

Top quark charge determination Top quark charge can: ü confirm SM theory (Qtop = 2/3) ü find 4 th generation quark (Qexo = -4/3) 3 steps: ücharge of W boson via leptonic decay ü pairing of b-jet + W using kinematic fitter ü flavor of b-jet using b-jet charge Expectations for L=5. 6 fb-1 N+ ≡ # of SM like pairs N- ≡ # of XM like pairs Lepton b-jet pair: üSM-like: Qbjet Q(l) < 0 üXM-like: Qbjet Q(l) > 0 2021 -12 -31 S. Tokár, UK FMFI 16

Top quark charge determination üData of L=5. 6 fb-1, analysed üLepton + jets with 2 btags ü f+ fraction of signal SM pairs lb pairs Expected from MC Observed in data SM XM 394 ± 66 306 ± 51 416 358 Observed f+ compared to MC trials for SM and XM P-values: PSM = 13. 4%, PXM=0. 014% Bayes factor: 2 ln(BF) = 19. 6 2021 -12 -31 Strong preference for SM S. Tokár, UK FMFI 17

Conclusions q Slovak physicists have participated in many CDF analyses and made a significant contribution: ü Top quark properties ü Higgs search ü Soft QCD ü Important service works q It was and still is an excellent school for young scientists q. A very good preparation for LHC physics q Not mentioned: our Ph. D student in postdoc positions outside of Slovakia (M. Kreps, Karlsruhe, B-physics at CDF) 2021 -12 -31 S. Tokár, UK FMFI 18

CP Violation in Bs J/yf ü CP violation in Bs J/yf is important probe for new physics in Bs mixing ü In SM CPV in mixing is tiny (Im. Vts 0) B 0 s J/ final state: a mixture of CPeven and CP-odd states – distinguished using decay product angular distribution ü About 6500 signal events ü Consistency with SM: 44% ü Large contribution from new physics cannot be excluded

Thank You ! 2021 -12 -31 S. Tokár, UK FMFI 20