SUGRA Searches at the Tevatron Dan Claes University of Nebraska representing the CDF and D0 Collaborations The Conference on Higgs & Supersymmetry Laboratoire de l'Accélérateur Linéaire Orsay, France March 19-22, 1999

“Precise measurement of the positive muon anomalous magnetic moment” (submitted to PRL February 23, 2001) “Many people believe that the discovery of supersymmetry may be just around the corner. We may have opened the first tiny window to that world.” “We are now 99 percent sure that the present Standard Model calculations cannot describe our data.”   = (g  2)/2   (SM)= (6.7)  (0.57 ppm)   (SM)   (exp)= 43(16) 

Though just 5½ years ago...

Fig. 2 R b and R c data [2] and the SM predictions [5].

SUPERSYMMETRY New symmetry unifying particles of different spin within multiplets -solves “fine-tuning” provided M SUSY < 1 TeV -allows unification of the gauge couplings -includes quantum gravity

Particle Name Symbol Spartner Name Symbol gluon g gluino g charged Higgs H  chargino W 1,2 charged weak boson light Higgs h neutralino Z 1,2,3,4 heavy Higgs H pseudoscalar Higgs A neutral weak boson Z photon  quark q squark q R,L lepton l slepton l R,L ~ ~ ~ ~ ~

Minimal Supersymmetric SM Extension adding the fewest new particles 2 Higgs doublet h 0 H 0 A 0 H +  and described by 4 parameters M 1 U(1) M 2 U(2) gaugino mass parameter at EW scale  higgsino mass parameter tan  ratio of VEV of Higgs doublets scalar sector described by MANY mass parameters different SUSY breaking different class of models

MSSM Assumptions: SUSY particles are pair produced Lightest SUSY particle (LSP) is stable

SUSY Symmetry Breaking SUGRA   GeV) Lightest SUSY particle is 5 free parameters m o common scalar mass m 1/2 common squark mass A o trilinear coupling tan sign(

Production has less dependence on SUSY parameters than decays Squarks/gluinos dominant if kinematically accessible Cross sections for scalar leptons are small ggg q Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Signal Cross Sections

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay If light, squarks and gluinos should be copiously produced at the Tevatron g g  q* qq qq g qq qq q q

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay qq gg  01 01 q  01 01 q q Assuming R-partity is conserved, squarks and gluinos can decay directly into the LSP (  0 1 ). or cascade down to the LSP  qq gg q So that the dominant signature for pp  qq, qg, gg + X is jets+E T    q q q qq 0202 qq  01 01 qq  g g qq q q q  1 1 q q  01 01 qq

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay The Tevatron Run Cross sections for new physics is small compared to Standard Model processes But CDF and D0 both recorded over 100 pb-1 of data

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay The Tevatron Run DØ Precision tracking: vertexing, b-tagging, lepton identification Powerful calorimetry: e, , E T

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay D0 MET and Jets Analysis pp  q,g  jets + E T large branching ratio, but suffers from enormous backgrounds QCD multijet events w/faked E T W/Z+jets t t    Used E T trigger, basic selection criteria: E T j1 >115, E T j3 >25 GeV E T >75 GeV jets and E T not aligned Reduce QCD H T (  i >1 E i T ) > 100 GeV Reduce W/Z veto isolated  with P T > 15 GeV Reduce W/Z

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Jet-E T Correlations Jet1 Jet2 Jet3 ETET    3   MET, Jet1  vs  MET, Jet2  Low Et JET MIN Trigger with offline Met > 10 GeV cut

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Jet-E T Correlations

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay D0 MET and Jets Analysis Final E T, H T cuts tuned to optimize S /  B across (m0, m1/2) plane 79 pb-1 of data analyzed Expected: 8.3  3.5 events Observed: 15 M q > 250 GeV (95% C.L.) M g > 260 GeV (M g =M q ) M g > 300 GeV (small m o ) ~ ~ ~ ~ ~ Phys.Rev.Lett (1999); hep-ex/990213

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay D0 MET and Jets Analysis Phys.Rev.Lett (1999); hep-ex/ ~ ~ ~ ~ ~ M q > 250 GeV (95% C.L.) M g > 260 GeV (M g =M q ) M g > 300 GeV (small m o )

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay CDF MET and Jets Analysis starting with basic cuts similar to DO Missing E T trigger cleanup jets projected to calorimeter gaps Blind Box method defines signal region by : E T >70 GeV H T (  i >1 E i T ) > 150 GeV N trk iso (isolated tracks)=0 indirect lepton veto

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay E T predominantly from mis-measured QCD events

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay QCD E T comparison:data(JET20+JET50) & predictions(Herwig)

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay CDF MET and Jets Analysis Main backgrounds QCD, W/Z+jets, tt

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay CDF MET and Jets Analysis Expected: 76.02±12.8 events Observed 74

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay CDF MET and Jets Analysis Expected: 76.02±12.8 events Observed 74 For m q  m g m g > 300 GeV/c 2 For m q 570 GeV/c 2 For m q >> m g m g > 195 GeV/c 2 ~ ~ ~~ ~~

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France CDF Dilepton + Jets Search Squark & gluino cascade decays can also lead to dilepton final states pp  q, g    1  0 2 +jj  jj + E T Selection cuts on CDF’s dilepton trigger: 2 isolated leptons, P T > 11, 5 GeV 2 central jets E T > 15 GeV, |  | < 2.4 E T > 15 GeV q qq q ~ ~ ~q ~q~q ~q  0 2   1 q ~ ~ 0101 ~ 0101 ~ Z* W* g

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France CDF Dilepton Backgrounds Heavy quark and di-boson production Require LS leptons. Final M cut rejects Z-production.

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France CDF Dilepton + Jets Search Expect: 0.55  0.25  0.08 events Observe: 0 events

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France Dilepton mSUGRA Search Squark and gluino search through dilepton final states pp  SUSY  jj + E T Selection, optimized for different regions of mSUGRA parameter space, made by (52 different) combinations of E T jet 1,2 > 20 GeV or 45 GeV (optionally, also require E T jet3 > 20 GeV) ee signatures: E T e1 > 17 GeV, E T e2 > 15 GeV e  signatures: E T e > 17 GeV, E T  > 4 GeV, 7 GeV or 10 GeV  signatures: E T  1 > 20 GeV, E T  2 > 10 GeV E T > 20, 30, or 40 GeV q qq q ~q ~q~q ~q  0 2   1 q ~ ~ 0101 ~ 0101 ~ Z* W* g

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France Dilepton mSUGRA Search Background sources QCD Multijet, W+jets estimated from data t t, Z + jets SPYTHIA-based Monte Carlo (FMC0) 108 pb -1 of data analyzed M g = M q > 255 GeV 95% C.L. for tan  = 2 ~

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France Charginos and Neutralinos Production of   1  0 2 will lead to trilepton final states with E T perhaps the cleanest signature of supersymmetry. pp  q, g    1  0 2  + E T ~ ~ 1 021 02 ~ ~ 0101 ~ 0101 ~ W* Z* W* qqqq qqqq 102102 ~ ~ 11 ~ 0202 ~  ~ 0101 ~   *  ~  0101 ~ ~ q* ~

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France Trilepton + Jets Search Selection cuts :  3 (e,  ) with P T > 5  22 GeV require Opposite Sign Leptons (CDF) E T > GeV mass and topological cuts Both CDF and DO searched for trileptons (e,  ) in Run I PRL 80, 1591 (1998); PRL 80, 5275 (1998) Very low background Drell-Yan + fakes heavy flavor production ZZ, WZ

Daniel Claes, University of Nebraska LincolnHiggs SUSY Conference 2001 Orsay, France Trilepton + Jets Search CDF Expected: 1.2  0.2 Observed: 0 DO Expected: 1.3  0.4 Observed: 0 100<m 0 <2500 GeV/c 2 a) m ½ =50 GeV/c 2 b) m ½ =75 GeV/c 2 c) m ½ =100 GeV/c 2 d) m ½ =120 GeV/c 2

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Run II Upgrades Main injector Tevatron DØ CDF Accelerator upgrade Run I Run II total integrated luminosity 120 pb -1 2 fb -1 /2 years (20 fb -1 extended run) instantaneous luminosity ×10 30 /cm 2 sec 2×10 32 /cm 2 sec bunch crossing intervals 3.8  sec 132 nsec beam energy 1.8 TeV 2.0 TeV complemented by major detector upgrades Run II has begun with Fermilab’s Main Injector (commissioned June 1999) New anti-proton storage ring

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay The DO Detector Upgrade retain the uranium/liquid-argon calorimeter retain most of its full-coverage muon system But the entire tracking volume is being replaced shorter bunch spacing, higher radiation levels New Detector Elements inner silicon vertex detector 8 layers of scintillating fiber tracking 2 Tesla superconducting solenoid scintillator-based preshower detecto

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay DO Upgraded Triggering LEVEL 1 (trigger decisions within few  sec) calorimeter trigger unchanged new fiber tracker trigger adds new preshower detector LEVEL 2 (trigger decisions within 100  sec) global processors run algorithsm correlating info from different subdetectors e.g., calorimeter-preshower-track matches E/p and invariant mass cuts Event buffering between each trigger stage deadtime due to pileup decreased event transfer rates into LEVEL 3 1 kHz LEVEL 3 rejection of 50 average processing time < 100msec)

Run II machine goals: 1) Run IIa to achieve a luminosity of 5x10 31 cm -2 s -1 and an integrated luminosity of 2 fb -1 2) Run IIb to achieve a luminosity of 2x10 32 cm -2 s -1 and an integrated luminosity of ~20 fb -1 The number of anti-protons in the ring has been one of the major limiting factors in Tevatron luminosity. The anti-proton stacking rate will be increased to 2x10 11 /hr from 7x10 10 /hr The machine will operate with 36x36 bunches (396 ns spacing) initially and (132 ns) eventually.

a new massive silicon vertex detector – 7 layers extending to 28 cm in radius – deadtime-less SVX3 readout electronics a new central outer tracker (COT) hermetic scintillator tile plug & forward calorimeter large trigger bandwidth Time-of- flight added End Plug extended to larger  COT replaces CTC SVX replaced, Si layer added to beampipe, Intermed. Si Layers added Shower max edded Forward calorimeter eliminated + New Trigger, DAQ

entirely new tracking improved muon spectrometer new trigger and DAQ system – 2T super conducting solenoid – disk/barrel silicon detector – 8 layers of scintillating fiber tracker – preshower detectors Forward Mini- drift chambers Shielding New Solenoid & Tracking: Silicon, SciFi, Preshowers + New Electronics, Trigger, DAQ Forward Scintillator Central Scintillator

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay RunII Squark and Gluino Prospects Multijets with E T remains the dominant signature of q ’s & g ’s Critical Understanding the tail of the E T distribution in multijet events Methods to accurately estimate multijet backgrounds Large tan  :enhanced g /   i /  0 i decays to 3rd generation particles Critical  -lepton and b -quark trigger and identification capabilities. ~ ~ ~ ~

With 2 fb -1, DØ and CDF will probe m 1/2 up to ~150 GeV corresponding to M gluino  400 GeV (for m 0 <200 GeV) Run II improvements: 1)improved E T resolution – more hermetic calorimeter (CDF) – better vertexing (DØ) 2)Advanced analysis methods, improved tools Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay RunII Squark and Gluino Prospects

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Chargino and Neutralino Prospects Trilepton signatures with large  content Major backgrounds: W+jets, Z+jets, WZ,… Critical: large acceptances and high efficiencies for high & low p T leptons including 

Daniel Claes, University of Nebraska-Lincoln Higgs SUSY Conference 2001, Orsay Chargino and Neutralino Prospects Run II improvements: 1) extended coverage improves lepton acceptances 2) lepton charge and better  momentum measurements reducing backgrounds (DØ) 3) new preshower detectors 4) major effort on  identification built upon Run I experiences M chargino reach >150 GeV for most of parameter space M chargino reach ~200 GeV for small to medium values of tan 