Review of Recent Top Quark Measurements

Transcription

1 Review of Recen Top Quark Measuremens Ann Heinson Universiy of California, Riverside Vh Renconres du Vienam New Views in Paricle Physics Hanoi, Vienam Augus 5, Theory Reconsrucion Backgrounds Resuls Top quark pairs Single op quarks Top properies Top mass Fuure

2 Top Quarks Spin / fermion, charge +/3 Isospin parner of he oom quark ~x heavier han is parner g 7. ±.3 GeV from Tevaron Run I g proon q g g q g aniproon g Produced mosly in pairs a he Tevaron g 5% qq, 5% gg Cross secion =. ±. p a NNLO

3 Top Quark Decay Top decays efore i can hadronize Lifeime Γ op = (.5 GeV) << Scale Λ QCD = ( MeV) Top decays o W % of he ime Classify evens y he decays of he W s Dilepons e + e + + E T e µ + + E T µ + µ + + E T Lepon+jes e + jj + + E T µ + jj + + E T Alljes jj + jj + Need o reconsruc and idenify: Elecrons, muons, ligh-jes, -jes, and missing ransverse energy τ+τ % τ+µ % τ+e % µ+µ % µ+e % "dilepons" e+e % W + e+jes 5% 3 l +, q ν, q' "alljes" % τ+jes 5% µ+jes 5% "lepon+jes"

4 Deecion and Reconsrucion Tevaron deecors have new racking sysems, many upgrades o calorimeers and muon sysems Run II, April July CDF has colleced 5 p of daa ( p wih SVXII) DØ has colleced 5 p of daa Analyses shown here use p several million riggered evens Selec final samples o maximize measuremen sensiiviy Find ~ op quark evens aove ackground so far

5 W Backgrounds q' g 5 W W Evens wih real W or Z osons W+jes Z+jes W g W W W WW, WZ, ZZ Evens wih misidenified lepons Mulije evens wih a je misidenified as an elecron +jes wih a misidenified elecron or muon from a decay q W+jes W + l ν l + ν W W Miscellaneous sources Cosmic rays, muliple pp ineracions, paern recogniion misakes, ec. q q g W c W W For mos decay channels, processes wih a real W oson and real jes are he mos difficul o remove +je q g c q'

6 -Je Idenificaion DØ Silicon Microsrip Tracker 79,57 channels in arrels and disks. m -ID algorihms Secondary verex SVT Je lifeime proailiy JLIP Couning signed impac parameer CSIP Muon-in-je SLT Secondary Verex Decay Lifeime Je CDF Silicon Verex Deecor II plus an inner layer and ouer layers 7,3 channels, in arrels -ID algorihms Secondary verex SVX Muon-in-je SLT Primary Verex Impac Parameer Proailiy o ag a leas one je in a even = 55% Proailiy for a fake ag =.% 7 cm

7 Cross Secion Compare measuremens wih σ heory (pp + X) =. p.3% of he W cross secion The CDF collaoraion has made measuremens Dilepons = 3, Lepon+jes =, Alljes = The DØ collaoraion has made 7 measuremens Dilepons =, Lepon+jes =, Alljes = Baseline samples for measuremens of op quark properies 7

8 CDF Dilepons and Alljes Xsecs % Numer of evens CDF II preliminary daa (93 p ),.7 p To kgd ± σ Z ττ WW/WZ DY ee, lepon fakes 3% Toal error on Xsec Numer of Jes.933 MC 5 Me (GeV) Fixed Bknd.) Numer of Jes 5 WW MC Daa Me (GeV).53 Numer of Jes Z->τ τ MC CDF II Preliminary eµ space Me (GeV) 5 + H T + OS Numer of jes in dilepon + missing E evens T 3 5 Numer of Jes 5 Me (GeV) Numer of Jes Me (GeV) Two opposie-sign lepons, H T > GeV Fi all SM processes in E T N jes plane enries/je in Even coun per je in CDF II - 97 p WW + WZ + ZZ 3% % + Drell-Yan + fakes + (σ SM =.7 p) Final cu region Tagged jes CDF Run II preliminary, L=5 p Background uncerainy Background Background + op (σ=.7 p) Daa N je jes 5jes jes 7jes jes A lepon and an opposie-sign rack Cu on A, C, E T j:j, E T j3:j, SVX-ag

9 CDF Lepon+Jes Xsecs 9 % Numer of agged evens CDF II Preliminary W,Wcc,Fake non-w Drell-Yan Wc WW, WZ, ZZ, Z ττ Single op Toal Bckg ± σ Daa ( ± 7 p ) 9% Numer of Doule agged evens CDF II preliminary misags W Wcc WZ Single op ar (.7p) To kgd ± σ Daa ( p ) 3 Numer of jes in W+jes 3 Numer of jes in W+jes Muon-in-je ag Two or more SVX-agged jes CDF Preliminary (95 p ) CDF Run II Preliminary (~. p ) 5% evens N je 3 f W σ (p) op W+jes oher EW QCD 33% numer of evens / GeV W+3 or more jes sample + BKG (HERWIG) BKG (from daa) 3 5 H T (GeV) Leading je ET (GeV) Fi o H T disriuion (no ag) SVX-ag and fi o E T (je) disriuion

10 CDF L+Jes Xsecs CDF Resuls CDF II preliminary CDF Run II Preliminary % % Numer of agged evens misags evens Numer of jes in W+jes CDF Preliminary nnou (95 p ) QCD fakes W+jes Signal Comined Fi Daa ar: 7. QCD:.3 W+jes 7. W Wcc non-w Wc WW,WZ,Z ττ Single op To kgd ± σ Daa ( p ) require H T > for 3 jes SVX-ag and H T > GeV 3. ±.9%. ±.%.7 ±.% Nj 3 m =75 GeV/c Lepon + Track Lepon + Lepon Dilepons: SM Fi 7. (L= p ) ±.3.7 ±.7 3. Lepon + Jes: Kinemaic.7 ±. ±. (L= 95p ). Lepon + Jes: Kinemaic NN.7 ±. ±. (L= 95p ). Lepon + Jes: Verex Tag + Kinemaic. ±.5 ±. (L= p ). Lepon + Jes: Verex Tag 5. ±. ±. (L= p ). Lepon + Jes: Doule Verex Tag 5. ±. ±. (L= p ).9 Lepon + Jes: Sof Muon Tag. ±. ±.9 (L= p ). ±..5. (L= 93p ) ±... (L= p ) ±.5. ± NN oupu Neural Ne Oupu Fi o oupu of 7-variale NN All Hadronic: Verex Tag 7. ±.5 ±.7 (L= 5p ) σ(pp ) (p).5.3

11 DØ Dilepons, Alljes, L+Jes Xsecs 39% Numer of Evens DØ Run II Preliminary W W 7 Fakes * Z/γ 5 Daa Jes H T (GeV) 5% Numer of evens Daa ar Backgrounds DØ Run II Preliminary Je mulipliciy New Resul Two opposie-sign lepons, M ll and H T Elecron+muon, SVT-ag evens /.5 3 DO RunII preliminary inegraed luminosiy: p re-normalized ackground verex agged daa expeced conriuion 7% % Aplanariy A DØ Run II Preliminary final neural nework oupu Scalar Energy H T [GeV] Three NNs, 9+ variales, SVT-ag Muon-in-je ag, loose A and H T cus

12 DØ L+Jes Xsecs DØ Resuls 3% Likelihood fi o H T, A, E-vars (no ag) 39% 7% No. of agged evens New Resuls µ+jes/csip, = ag QCD Wl Wc Wcc W W VV Z ττ s 5 no of evens 3 daa µ+jes fied ar fied W+jes fied QCD DØ Run II Preliminary DØ Run II Preliminary.... Likelihood Discriminan µ+jes/svt, = ag SVT Daa mu+jes QCD W+ligh Wc Wcc W ar -> ll VV Z -> ττ Single Top ar -> ljes 3 Je mulipliciy CSIP ll lj 3 Njes DØ Run II Preliminary DØ Run II Preliminary QCD Wl Wc Wcc W W VV Z τ + τ - single op ll l+jes µ+jes/csip, ags 3 Njes Likelihood fi wih =, SVT or CSIP ags No. of agged evens Daa mu+jes QCD W+ligh Wc Wcc W ar -> ll VV Z -> ττ Single Top ar -> ljes SVT µ+jes/svt, ags 3 Je mulipliciy CSIP 3 p 5 p p p p p p 9 p 9 p 9 p 5 p 5 p 5 p p DØ Run II Preliminary 3 σ(pp ) [p] eµ ee µµ dilepons e+jes (no ag) µ+jes (no ag) l+jes (no ag) e+jes (SLT) µ+jes (SLT) l+jes (SLT) eµ (SVT) µ+jes (CSIP) µ+jes (SVT) alljes Xsec in p

13 Cross Secion Summary Run I resuls: CDF σ( )= p DØ 3% uncerainy Agree wih calculaion, 5. ±.3 p Run II cross secion is 3% higher han Run I ( s =. TeV.9 TeV) Theory calculaion is. ±. p Bes Run II measuremens so far are CDF lepon+jes resuls SVX-ag and H T > GeV,.7 ±.9 p wih p Neural nework wih 7 variales, wih 95 p. p Consisen wih heory σ(pp ) Run II resuls from many channels no ye comined Bes measuremen uncerainies are % so far Aiming for % wih f σ( )= 5.7 ±.7 p 3

14 Single Top Quarks Elecroweak producion of op quarks no ye oserved Two main producion modes a he Tevaron s-channel q q' -channel q σ( pp,,+x) =. ±.7 p q' W + g W σ( pp q, q,+x) =. ±. p Aou half he cross secion of, u ackgrounds are much higher Single op evens can e used o measure V wihou assuming hree quark generaions, and hence o deermine op quark widh Oservaion is hoped for wih f of daa

15 CDF Single Top DØ Single Top 5 CDF Run II Preliminary Evens/ GeV p Enries single op non-op SUM Daa H T GeV Yield [couns/5gev] 5 e+ µ, JLIP+SLT DO Run II Preliminary Daa fake-lepon W/Z + jes -channel s-channel New Resuls Fi o H T lνalljes and SVX -ag σ(s + -channels) < 3.5 p (95% CL) Evens per. unis CDF Run II Preliminary Enries 5 Daa Fi Sum -channel Background 3 5 H T [GeV] H lνjj T > 5 GeV & SVT, JLIP, SLT -ag σ(s-channel) < 9 p (95% CL) σ(-channel) < 5 p σ(s + -channels) < 3 p -3-3 Q η Fi o (Q x η) and SVX -ag σ(-channel) <.5 p (95% CL)

16 Top Quark Properies Many ineresing measuremens are possile all need high saisics Producion g and W couplings Spin correlaions New paricles Decay Widh Γ CKM marix elemen V Gluon radiaion W oson heliciies Branching fracions p T specra Charge Rare decays

17 CDF W Heliciy DØ W Heliciy 7 (Run II) (Run I Daa) Lepon+jes Dilepons L/Lmax m op [GeV]..... F Fi lef-handed (F L ) and longiudinally polarized (F ) W oson fracions in lepon p T +. F =..7 (lepon + jes) F <.5 95% CL (dilepons) L/L max.... SM F F = , <. (comined) Marix elemen mehod o reconsruc evens F =.7 (Sandard Model) Low dilepon value caused y excess of evens a low lepon p T F =.5 ±.3 (lepon+jes)

18 Top Quark Mass Ten years of measuring he op quark mass Mehods have developed significanly over his ime Firs, jus kinemaic fiing and compare o emplaes in m op Then add more variales and use likelihoods Bes mehods use all availale informaion Measuremen uncerainy improves wih oh ime and more daa The firs measuremens (995) had a 7% uncerainy Curren Run II measuremens have a 5% uncerainy each Run I comined measuremen has a.% uncerainy Run II goal is a % uncerainy on m op (±.5.5 GeV)

19 CDF Top Mass Run II Daa 9 numer of evens / GeV CDF Run II preliminary = 75 GeV) MC (M op DATA Log(likelihood) CDF Run II preliminary m op = 75. GeV (sa) ±.(sys) (% uncerainy) Mass / GeV Mass / GeV ) Evens/(5 GeV/c CDF Run II Preliminary ( p ) Daa ( evs) Signal + Bkgd Bkgd only Templae Mehod, Dilepon Evens ( ee, 3 eµ, µµ) Reconsruced Mass (GeV/c ) -ln(l/l max ) CDF Run II Preliminary 5 (GeV/c ) Templae Mehod, Lepon+Jes Evens wih SVX -ag M m op = 7.9 GeV (sa) ±.5(sys) (5.% uncerainy)

20 CDF Top Mass Run II Daa ins) Evens (5 GeV/c CDF Run II preliminary, p daa (M = GeV/c ) op W/WW/WZ non-w QCD single op misags log (L) m op = 79. GeV.3 +. (sa)±.(sys) (5.% uncerainy) M op (GeV/c ). Mulivariae Templae Mehod, 33 Lepon+Jes Evens wih SVX -ag ) Evens/(Gev/c 7 CDF Run II Preliminary ( p ) Signal MC : M op = 75GeV/c 5 3 Maximum Likelihood Mass MC Predicion Signal ar(mc) Backgroud(MC) Daa evens Maximum Likelihood M Top (GeV/c ) -ln(l/l max ) CDF Run II Preliminary ( p ) M Top (GeV/c ) m op = 77. GeV (sa) ±.(sys) (.5% uncerainy) Dynamical Likelihood Mehod, Lepon+Jes Evens wih SVX -ag

21 DØ Top Mass Run I Daa Marix Elemen Mehod All feaures of individual evens are included Well-measured evens conriue more informaion han poorly-measured ones Run I lepon+jes evens re-analyzed L / Lmax... m op =. GeV ±3.(sa) ±.(sys) Top quark mass (GeV/c ) Resul pulished in Naure, June Firs experimenal HEP paper pulished in ha journal (3.% uncerainy) Run II Daa Three measuremens in progress Templae Mehod Ideogram Mehod Marix Elemen Mehod Resuls availale soon

22 Top Quark Mass Summary Bes resul Average of DØ and CDF measuremens using Run I daa (Run II resuls no ye comined) Top and he Higgs oson Top quark mass gives us informaion aou he Higgs oson Top couples srongly o he Higgs Top plays a criical role in loop correcions Mos likely Higgs oson mass is 7 GeV 95% CL upper limi is 5 GeV χ 5 3 m op = 7. ±.3 GeV Region excluded y direc searches All daa, wih old world-average M op All daa, wih DØ's new M op All daa, wih new world-average M op Theory uncerainy Higgs Boson Mass (GeV/c )

23 Fuure Top Quark Physics Large Hadron Collider, pp a s = TeV, sar-up April 7 will e 9% from gg, % from qq (opposie o he Tevaron) 7 pairs per year for firs hree years, hen per year (Compare wih Tevaron, produced per year) Linear Collider, e + e a ~ s = 3 GeV (m ) for op measuremens cross secion lower han Tevaron, u luminosiy much higher pairs per year and much smaller ackgrounds 3

24 Expeced Fuure Sensiiviies All op quark properies, SM and non-sm couplings, rare producion and decay modes will e sudied in deail (excep rare SM decay WZ, which canno e reached a he LHC) Top quark mass Similar precision expeced a LHC and Tevaron, ~ GeV Limied y final sae radiaion A LC, scan hreshold, fi m op (S), α s (M Z ), Γ op, g H o measuremens of σ, p op, A op FB, measure m op (S) o MeV Convering m op (S) o m op (MS) limis m op (MS) uncerainy o ~ MeV M W [GeV] Experimenal errors % CL: LEP/Tevaron (oday) Tevaron/LHC LC+GigaZ M H = 3 GeV M H = GeV SM ligh SUSY MSSM heavy SUSY Based on Heinemeyer, Weiglein m op [GeV]

25 The Tevaron is he only op quark facory unil LHC urn-on in 7 Summary The collider is meeing performance expecaions DØ and CDF are collecing daa a high efficiency Expec aou x more daa in Run II han Run I ( p f ) Many firs measuremens now availale All consisen wih he Sandard Model Need more daa o reduce saisical and sysemaic uncerainies Need more ime o apply more sophisicaed analysis mehods Precision op quark physics program is jus around he corner The op quark will provide a unique window ino hidden pars of he Sandard Model and many regions eyond 5