Mattione Update 06012011

Overview

• Generated and analyzed 10000 X(2000) -> b₁π^-; events following the instructions here.
  • Run using the latest build from this morning.
• Decay chain:

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

Track Multiplicity

# Generated events = 10000

# Events with 2+ photons = 9669
# Events with 2+ π+'s = 7749
# Events with 2+ π-'s = 8248
# Events with 2+ protons = 1040 (should only be 1 !!)
# Events with enough tracks for the X (2+ photons, 2+ π+'s, 2+ π-'s) = 6259

• # Photons per Event

• # π⁺'s per Event

• # π^-'s per Event

• # Protons per Event

X(2000)⁰ Mass

• X(2000)⁰: The combination of tracks yielding a mass closest to the X(2000)⁰.
• 10000 generated events: ~63% reconstruction efficiency, was ~52% on b1pi wiki page.
• However, very significant high-mass tail.

Code as of 06/01/2011

π⁰ Mass

• π⁰: The combination of tracks yielding a mass closest to the π⁰.
• Significantly worse resolution than originally.

Code as of 06/01/2011

• π⁰: Original version on b1pi wiki page:

Original version on b1pi wiki page

γ Reconstruction

• γ's were reconstructed with p & E = 0 until a fix by David Lawrence this morning.
• For each of the generated photons that were matched with reconstructed photons, Δp (generated - reconstructed) vs generated p:

Code as of 06/01/2011, Δp (generated - reconstructed) vs generated p