PHYS%205326,%20Spring%202003

1
PHYS 5326 Lecture 8
Monday, Feb. 17, 2003 Dr. Jae Yu

1. Interpretation of Sin2qW results
2. The link to Higgs

Move Wednesdays class and the makeup class to
Friday 9am-12pm in rm 200, this week only!!
2
Last Weeks Homework Assignments

• Process the transferred TMB data files and
  convert them into TMBtree for root analysis
• You can work together on this one
• One person can produce TMBtree for all
• Due next Monday, Feb. 17
• Produce an electron ET spectrum of the highest ET
  electrons in your samples
• Due next Wednesday, Feb. 19

3
MC to Relate Rnexp to Rn and sin2qW

• Parton Distribution Model
• Correct for details of PDF model ? Used CCFR data
  for PDF
• Model cross over from short nm CC events

4
MC to Relate Rnexp to Rn and sin2qW

• Neutrino Fluxes
• nm,ne,nm,ne in the two running modes
• ne CC events always look short
• Shower length modeling
• Correct for short events that look long
• Detector response vs energy, position, and time
• Continuous testbeam running minimizes systematics

5
sin2qW Fit to Rnexp and Rnexp

• Thanks to the separate beam ? Measure Rns
  separately
• Use MC to simultaneously fit and
  to sin2qW and mc, and sin2qW and r

• Rn Sensitive to sin2qW while Rn isnt
• Rn is used to extract sin2qW and Rn to control
  systematics
• Why???

6
sin2qW Fit to Rnexp and Rnexp

• Single parameter fit, using SM values for EW
  parameters (r01)

• Two parameter fit for sin2qW and r0 yields

7
NuTeV sin2qW Uncertainties
1-Loop Electroweak Radiative Corrections based on
Bardin, Dokuchaeva JINR-E2-86-2 60 (1986)
8
NuTeV vs CCFR Uncertainty Comparisons
Beamline worked!
Technique worked!
9
Comparison of New sin2qW
Comparable precision but value smaller than other
measurements
10
SM Global Fits with New Results
Without NuTeV c2/dof20.5/14 P11.4
With NuTeV c2/dof29.7/15 P1.3
Confidence level in upper Mhiggs limit weakens
slightly.
LEP EWWG http//www.cern.ch/LEPEWWG