Mattione Update 11072011

Procedure

• Reconstruct π(1600) -> b1π events with t-slope = 2.0 using both the 334 and 1234 segmentations
• Plot Δβ vs p for π⁺ candidates to see proton, π⁺ separation.

π(1600) -> b1π Events

p vs. θ

• p vs. θ
  • NOTE: time improvement only at forward angles, so will be negligible for protons in this reaction.

π+'s

protons

π⁺ BCAL Δβ vs p

Δβ = β_p - β_t = p/sqrt(p*p + m*m) - path/(c*TOF)

334 Segmentation

• π(1600) -> b1π Events, π⁺ Candidates, BCAL Δβ vs p, 334 Segmentation

p = 1.2 GeV/c, 334 Segmentation	p = 1.4 GeV/c, 334 Segmentation
p = 1.5 GeV/c, 334 Segmentation	p = 1.6 GeV/c, 334 Segmentation

Problems

• π⁺ Reconstructed BCAL Time Resolution Sample dE bin:
  • Expect to see significant resolution improvement between 15 < θ < 35.
  • NOTE: For 1234 Scheme: the shower time was smeared by: σ_smear = sqrt(σ²_{t_1234_Target} - σ²_{t_334_NoSmear}), where σ_{t_1234_Target} = σ_{t_334}*Improvement_Ratio, Improvement_Ratio = σ_{t_1234} / σ_{t_334}

• π⁺ BCAL Shower Δt Sample θ bin, Time Smearing Disabled:
  • Δt = t_reconstructed - t_true
  • Instead of a spike at zero, the long tail is due to the hit clustering.
  • Will decrease 1234 time smearing to match expected resolution improvement to 334.

Reference

• Fit the results of David's study: Fit γ BCAL σ_{t_1234} / σ_{t_334} vs. θ in dE bins: show significant (> 10%) timing improvement is between 15 < θ < 35.
  • Don't trust fits at low-θ, so linearly-interpolate between 12 and 16 degrees.