Difference between revisions of "Mattione Study b1pi"

Revision as of 14:01, 23 May 2011

Overview

• Generated 100000 X(2000) -> b₁π^-; events following the instructions here.
• Decay chain:

 gamma p -> p X(2000)0
               |
               |-> b1(1235)+ π-
                    |
                    |-> ω π+
                          |
                          |-> ρ0 π0
                               |   |-> γ γ
                               |
                               |-> π+ π-

Event Count

# Generated events = 100000

# Events with 2+ photons = 57866
# Events with 2+ π+'s = 29372
# Events with 2+ π-'s = 30634
# Events with enough tracks for the X (2+ photons, 2+ π+'s, 2+ π-'s) = 4760

# Events with at least one π0 candidate: 57866
# Events with at least one ρ0 candidate: 58466
# Events with at least one ω candidate: 31012
# Events with at least one b1 candidate: 12163
# Events with at least one X(2000)0 candidate: 4760

Invariant Masses

• π⁰: Filled for all events with > 1 photon, filled for all possible photon combinations (so if three photons in an event, will fill 3 times).

• ρ⁰: Filled for all events with at least one π⁺ and at least one π^-, filled for all possible pion combinations (so if two π⁺'s and two π^-'s in an event, will fill 4 times).

• ω: Filled for all events with at least: one π⁺, one π^-, and two photons. Filled for all possible ρ⁰ combinations, but for events with multiple π⁰ candidates the π⁰ with the closest mass was chosen.

• b₁: Filled for all events with at least: two π⁺'s, one π^-, and two photons. Filled for all possible combinations of these tracks (regardless of which π⁺ formed the Rho0).

• X(2000)⁰: Filled for all events with at least: two π⁺'s, two π^-'s, and two photons. Filled for all possible combinations of these tracks (regardless of which π⁺ & π^- formed the Rho0).

Comparison of Generated and Reconstructed Tracks

• NOTE: There was no observed φ-dependence on track reconstruction distributions.

Photons

• 100000 generated events, 2 photons per event: 200000 generated photons
• In thrown tree, the generated photons are matched with 174148 reconstructed photons.
  • However, only 170870 reconstructed photons in the "recon" tree!
  • Would expect at least 100000 - (200000 - 174148) = 74148 pi0 events, but get 57866 events with 2+ photons instead
    • Matching suspect, so following distributions may be suspect as well.

• For each of the generated photons that were matched with reconstructed photons, the generated p vs θ distribution:

• For each of the generated photons that were matched with reconstructed photons, the reconstructed p vs θ distribution:

• For each of the generated photons that were NOT matched with reconstructed photons, the generated p vs θ distribution:

• For each of the generated photons that were matched with reconstructed photons, delta-p (generated - reconstructed) vs generated p:

delta-p (generated - reconstructed) vs generated p

π⁺'s

• 100000 generated events, 2 π⁺'s per event: 200000 generated π⁺'s
• In thrown tree, the generated π⁺'s are matched with 151234 reconstructed π⁺'s.
  • However, only XXX reconstructed π⁺'s in the "recon" tree!
  • UPDATE: Would expect at least 100000 - (200000 - 151234) = 51234 events with 2+ π⁺'s, but get 29372 events with 2+ π⁺'s in reconstructed tree instead
    • Matching suspect, so following distributions may be suspect as well.

• For each of the generated π⁺'s that were matched with reconstructed π⁺'s, the generated p vs θ distribution:

• For each of the generated π⁺'s that were matched with reconstructed π⁺'s, the reconstructed p vs θ distribution:
• SUSPECT: I bet the spike in π⁺'s at #theta; ~= 0.77 rad are actually protons that were reconstructed with significantly lower momentum and were matched as π⁺'s.

• For each of the generated π⁺'s that were NOT matched with reconstructed π⁺'s, the generated p vs θ distribution:

• For each of the generated π⁺'s that were matched with reconstructed π⁺'s, delta-p (generated - reconstructed) vs generated p:

delta-p (generated - reconstructed) vs generated p