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KTeV pi0->4e plots

Updated May 8, 2008.

[pi0-> 4e Results]

Plots in Phys. Rev. Lett. 100, 182001 (2008).

• ddfeyn-gstar.eps, ddfeyn-gstar.pdf
  FIG.1: Lowest order Feynman diagram for pi⁰->e⁺e^-e⁺e^-. The direct contribution is shown; a second diagram exists with e₁⁺ and e₂⁺ exchanged.
  
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• meeee-split.eps, meeee-split.pdf
  FIG.2: Invariant e⁺e^-e⁺e^- mass for data events identified by teh preferred pairing as KL_L->pi⁰pi⁰pi⁰_DD (upper panel) and K_L->pi⁰pi⁰_Dpi⁰_D (lower panel).
  
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• x1x2-0214.eps, x1x2-0214.pdf
  FIG.3: Distribution of the kinematic variables x₁ and x₂ for signal event candidates (points) and signal Monte Carlo simulation with best fit form factor parameters (histogram).
  
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• phi-0214.eps, phi-0214.pdf
  FIG.4: Distribution of the angle phi, in units of pi, between the planes of the two e⁺e^- pairs. The solid histogram shows the Monte Carlo expectation for negative parity.
  
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Plots shown at DPF2002 by Pat Toale (May 2002)

• dpf.ps
  Transparencies
  
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• trksep.eps
  The distribution of the distance between two tracks at the first drift chamber are shown for various Monte Carlo events. DD: pi0->4e, 2D: 2 Dalitz decays, 1C: 1 Dalitz + 1 photon had an external conversion, and 2C: no Dalitz + 2 photons had external conversions.
  
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• mass.eps
  4e+4gamma mass distributions for the 1997(top) and 1999(bottom) data. The left plots show the pi0->4e candidates, and the right plots show the 2 Dalitz decay candidates.
  
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• ff0.eps
  MC distribution of x at generation. Distribution of x for a=0 (cross) and a=0.032 (hist). Bottom plot shows the ratio between them.
  
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• ff11.eps
  Distribution of x for data and tree-level MC (a=0). The bottom plot shows the data/MC ratio.
  
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• ff3.eps
  Distribution of x for tree-level MC (a=0) and MC with O(alpha^3) radiative corrections. The bottom plot shows the ratio between them. Note that the ratio is similar to f11.eps, which indicates that the data has a similar shape as MC with O(alpha^3) radiative corrections.
  
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• rc5.eps
  The distribution of phi (angle between two ee planes) for MC with radiative corrections (cross) and tree-level MC (histogram). The bottom plot shows the ratio between them. The horizontal axis is in units of radian/pi. Note that radiative corrections pull the distribution toward the center (1).
  
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• rc7.eps
  The distribution of phi for data (cross) and tree-level MC (histogram). The bottom plot shows the ratio betwen them. Note that the distribution for data is also pulled toward the center, as for MC with radiative corrections.
  
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• rc7.eps
  The distribution of phi for data (cross) and tree-level MC (histogram). The bottom plot shows the ratio betwen them. Note that the distribution for data is also pulled toward the center, as for MC with radiative corrections.
  
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Send corrections to Taku Yamanaka