Latest PRELIMINARY Results from Run 2 at DØ

Last updated – Jan. 11, 2002

Boaz Klima

(klima@fnal.gov)

Boaz Klima - Latest results from Run 2 at DØ

2

Z e+e- Candidates

2 EM objects, ET > 20 GeV,isolation and shower shape cuts

(uncalibrated energy scale)

Leo Chan, Rochester

e e

L~1.2pb-1

Boaz Klima - Latest results from Run 2 at DØ

3

W e Candidates

EM clusterwith track

EM clusterwith track

Vishnu Zutshi, NIULeo Chan, Rochester

e

ET

mT(e,) L~0.7pb-1

(uncalibrated energy scale)

Boaz Klima - Latest results from Run 2 at DØ

4

Higgs Candidate (just kidding…)DØ W + 2 jet candidate

Electron

Jet 1ET

raw = 17 GeV*

Jet 2ET

raw = 13 GeV*

Jet 1

Jet 2

Electron

* Jet ET corrections will be relatively large

ET

Boaz Klima - Latest results from Run 2 at DØ

5

Z +- Candidate

• Two muons recoiling against a jet

• Dimuon invariant mass ~ 55 GeV (with large uncertainty)

Onne PetersNIKHEF

Boaz Klima - Latest results from Run 2 at DØ

6

J/ +-

Di-muons reconstructed in the forward region

Roger Moore andAdam Yurkewicz, MSU

Boaz Klima - Latest results from Run 2 at DØ

7

Muons in Jets

Muon in jet (b candidate?)Hits in A,B,C layers

Onne Peters, NIKHEF

Back to backcalorimeter jets

Boaz Klima - Latest results from Run 2 at DØ

8

bb (b Candidate

Two jets tagged with muons

• Jet 1: ET ~ 18 GeV, pT ~ 7.4 GeV, pT

rel ~ .30 GeV

• Jet 2: ET ~ 13 GeV, pT ~ 5.4 GeV, pT

rel ~ .24 GeV

• …and in case you wonder, M ~ 12 GeV and Mjj ~ 29 GeV

3-D view

R-Z view

X-Y view

Boaz Klima - Latest results from Run 2 at DØ

9

Muons and JetsOnne Peters, NIKHEF

Muon + Jet cross section

(partially corrected) PT

Rel Distribution

(using Run 1 templates)

Boaz Klima - Latest results from Run 2 at DØ

10

Jetty EventsUsing R=0.7 Cone Algorithm with Run 1

corrections Alexander Kupco, Prague

2-jet event• ET

jet1~230GeV• ET

jet2~190GeV

3-jet event• ET

jet1~310GeV• ET

jet2~240GeV• ET

jet3~110GeV• ET~8GeV

Boaz Klima - Latest results from Run 2 at DØ

11

Jet Distributions

Alexander Kupco, PragueUsing R=0.7 Cone Algorithm (energies partially corrected)

Single Jet PT

Dijet Invariant Mass

Boaz Klima - Latest results from Run 2 at DØ

12

Jet Energy Calibration

Ia Iashvili, Riverside

jet

E' = ETxcosh(jet)

Pre-shutdown Data

Post-shutdown Data

Calorimeter Response in CC+EC

Boaz Klima - Latest results from Run 2 at DØ

13

J/ e+e-

Di-electrons reconstructed in CFT and SMT

Sergey Burdin, LAL

(uncalibrated EM energy scale)

Boaz Klima - Latest results from Run 2 at DØ

14

EM Energy Calibration Marie-Claude Cousinou, Marseille

Data - before Correction

Monte Carlo

P3=0.959 corresponds to a mass of 87.5 GeV

Data - after Correction

Boaz Klima - Latest results from Run 2 at DØ

15

Ks +-

Tracks reconstructed in the SMT detector

Black histogram – opposite-sign tracks

Red histogram – same-sign tracks

Dotted curve – fit to background

Full curve – fit to signal + background

Brad Abbott, Oklahoma

Boaz Klima - Latest results from Run 2 at DØ

16

Ks (+-) LifetimeTracks reconstructed in the SMT detector

Ariel Schwartzman, Buenos Aires

Boaz Klima - Latest results from Run 2 at DØ

17

Hits in SMT and CFT

Avto Kharchilava, Notre Dame

Boaz Klima - Latest results from Run 2 at DØ

18

Level 3 Calorimeter Trigger

EM clusters, pT > 10 GeVIsolated, EM fraction > 0.9

|| < 1.1

Jets, pT > 15 GeVR = 0.7 cone

|| < 1.1

fail (prescaled)

pass

fail (prescaled)

pass

Volker Buescher, Mainz