Analysis of D -> K-p p FOCUS

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Analysis of D -gt K-ppFOCUS Mike Pennigton

• Jon, Brian, Kalanand

Fig 1
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Overview

• 54,000 events, _at_ 96 purity
• 2 models
• Isobar, same as E791 (but includes 1410)
• Fit to Kappa mass not good, allow S-wave
  resonances to float
• K-matrix using LASS S-wave
• Both seem to provide acceptable chisq/NDF
• Consider I3/2 contributions, increasing in
  contribution with mass
• If there is a s pole, consistent with Kp
  scattering
• Watson Theorem holds in Elastic Scattering Limit

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Comparison with E791 Isobar
If Gaussian FF Is used in scalar Terms,
then Results are even More consistent with E791
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Treatment of the LASS s-wave

• Pole expansion of T-matrix
• Adler zero 0.23 GeV2, I1/2
• 0.27 I3/2
• Obtained from Fit to LASS data
• Extension below 825 MeV/c2 uses ChPT
• Data from

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Continued.

• FSI modification to the amplitude
• The P-vector replaces the complex coefficients
  used in isobar fit

where
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K-Matrix Fit Results

• Huge amount of interference between I1/2 and
  I3/2 Kpi S-wave amplitudes
• Not so surprising
• Total S-wave not so different from the isobar fit.

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S-wave Amplitudes
S
Phase
Total
I 1/2
I 3/2
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Implications for our Analysis

• Open to Discussion
• I3/2 component
• Do we care?

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Implications for our Analysis

• This analysis
• supports the Watson theorem by including a
  (large?) I3/2 component.
• We measure total S-wave
• Does nothing about the broad P-wave states
• How about I3/2 in the P-wave?
• We measure total P-wave (but do assume it is all
  I1/2 below 900 MeV/c2 )
• We might be able to include I3/2 in S-wave by
  constraining phases (and assume it is elastic??)