Difference between revisions of "Mattione Study b1pi"

Revision as of 11:42, 23 May 2011

• Generated 100000 X(2000) -> b1pi events following the instructions here.
• Decay chain:

 gamma p -> p X(2000)0
               |
               |-> b1(1235)+ pi-
                    |
                    |-> omega pi+
                          |
                          |-> rho0 pi0
                               |   |-> gamma gamma
                               |
                               |-> pi+ pi-

Event Count

# Generated events = 100000

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

# Events with at least one pi0 candidate: 57866
# Events with at least one rho0 candidate: 58466
# Events with at least one omega candidate: 31012
# Events with at least one bi+ candidate: 12163
# Events with at least one X(2000)0 candidate: 4760

Invariant Masses

• Pi0: Filled for all events with > 1 photon, filled for all possible photon combinations (so if three photons in an event, will fill 3 times).

• Rho0: Filled for all events with at least one pi+ and at least one pi-, filled for all possible pion combinations (so if two pi+'s and two pi-'s in an event, will fill 4 times).

• Omega: Filled for all events with at least: one pi+, one pi-, and two photons. Filled for all possible rho combinations, but for events with multiple pi0 candidates the pi0 with the closest mass is chosen (got lazy).

• B1+: Filled for all events with at least: two pi+, one pi-, and two photons. Filled for all possible combinations of these tracks (regardless of which pi+ formed the Rho0).

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

Comparison of Generated and Reconstructed Tracks

Photons

• 100000 generated events, 2 photons per event: 200000 generated photons
• In thrown tree, the generated photons are matched with 174148 reconstructed photons.
  • Would expect 100000 - (200000 - 174148) = 74148 pi0 events, but get 57866 events with 2+ photons instead
• However, only 170870 reconstructed photons in the "recon" tree!

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

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

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