ET 633 GeV 0.19

1
Testing QCD jet production
Run ?? at the Tevatron pp collider provides a new
level of precisionin the knowledge of QCD
processes in hadron collisions
R-? view
Motivation

• Jet production measurementsare stringent tests
  of QCD
• Perturbative QCD (pQCD)
• Parton Distribution Functions (PDFs)
• High transverse momentum (PT)tail sensitive to
  New Physics

Dijet Mass 1374 GeV/c2
ET 666 GeV? 0.43
ET 633 GeV? -0.19
Calorimeter LEGO view
Inclusive Jet Cross Section
b-jet Cross Section

• b-jets include most of b-quark remnants
• Small dependence on fragmentation
• b tagging uses displaced tracks inside jetsto
  reconstruct secondary vertices
• Extraction of b fraction by fitting Monte-Carlo
  templates to the Data

• Use KT algorithm preferred by theory
• Infrared and collinear safe to all orders in
  pQCD
• No merging / splitting issue
• Well defined comparison with Theory

High masses of B hadrons
Long lifetime of B hadrons
8 orders of magnitude!

• Good agreement between Data and Theory
• Data fully corrected to the hadron level
• NLO corrected for non perturbative effects
• Systematic errors dominated by jet energy scale
• NLO uncertainties mainly from PDFs
• Gluons at high x

Data fully corrected to the hadron level

• Comparison to Pythia Tune A as expected
• Comparison to NLO will come soon

2
Diboson Production

• W's and Z's are the standard candles of CDF

• All combinations of electroweak bosons can be
  pair-produced at the Tevatron.
• Tests production models and couplings between the
  electroweak force carriers.

• Our acceptance for these events in muon and
  electron channels is understood to 2.
• Track resolution dpT/pT 0.15pT
• Cross-section ratios can be used to determine
  fundamental parameters such as the width of the W
  boson

• W? photon PT spectrum sensitive to non-SM
  couplings.
• Z? search for resonances.

?W (CDF) 2079 41 MeV

• A future method for determining luminosities.

• WW production in hadron collisions firmly
  established for the first time in Run 2.
• An important discovery channel at the Tevatron
  LHC.

? - axis
l
l
E/p peak in W en events determines energy
scale

• Measurement strategy
• Calibrate tracker with muons from low-mass
  resonance decays
• Calibrate calorimeter with e tracks from W decays
• Model hadronic response using Z ll events

W Mass in the Standard Model
recoil
paEM
mW2
v2GF (1-mW2/mZ2)(1 - Dr)
Radiative corrections dominated by top, Higgs
Response and resolution from Z data
J/y mass independent of muon momentum
Total uncertainty 76 MeV (cf Run 1 79 MeV)