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KTeV KL->pi pi gamma plots

Updated August 29, 2006.

[KL->pi pi gamma Results]

Plots from [PRD74 (2006)] [PRL86 (2001)]

[top] PRD74 (2006) [PRL86 (2001)]

Plots in Phys. Rev. D 74, 032004 (2006)

• pmgmass4.eps, pmgmass4.pdf
  FIG.1. pi⁺pi^-gamma mass for events passing all K_L->pi⁺pi^-gamma physics cuts except for the M^pi+pi-gamma cut. Crosses are data and the solid line is fit to the background components.
  
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• cosprlplot8.eps, cosprlplot8.pdf
  FIG.2. Likelihood fit to the two indepedent variables in the K_L rest frame: a) the angle theta between the pi⁺ and the gamma in the pi⁺pi^- center of mass and
  
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• egprlplot8.eps, egprlplot8.pdf
  FIG.2.b) the photon energy spectrum E_gamma in the K_L rest frame. The compoenents of the photon energy spectrum and the cos theta spectrum due to the bremsstrahlung and M1 direct emission processes are shown.
  
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• 060214_6.eps, 060214_6.pdf
  FIG.3. 90% CL contours of g_M1 vs. a1/a2 for various experimental measurements; 90% CL results from the K_L->pi⁺pi^-gamma mode from this paper (5-shaded contour) with the 68% CL contour also shown (white contour); For comparison, we show the results from the K_L->pi⁺pi^-e⁺e^- mode for NA48 data (3-dotted countour) of Ref. [7], for KTeV 1997 data (2-dashed contour) in Ref.[5], and for KTeV 1997+1999 data (4-solid contour) of Ref.[6], and for a1/a2 from earlier KTeV 96 K_L->pi⁺pi^-gamma data (1-light gray vertical region) of Ref.[3].
  
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[top] [PRD74 (2006)] PRL86 (2001)

Plots in Phys. Rev. Lett. 86, 761 (2001)

• belz0404fig8.eps, belz0404fig8.pdf
  FIG.1. The decay K_L->pi⁺pi^-gamma arises preliminary from the contributions of the electric dipole (E1) "inner Bremsstrahlung" (left) and
  
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• belz0404fig7.eps, belz0404fig7.pdf
  magnetic dipole (M1) "Direct emission" (right) diagrams above.
  
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• linmas.eps, linmas.pdf
  FIG.2. (a) M_pipig distribution of cnadidate K_L⁰->pi⁺pi^-gamma events, all other cuts applied. Arrows indicate final cuts at M_k+-8 MeV/c².
  
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• logpt2.eps, logpt2.pdf
  (b) Kaon transverse momentum squared (P_T²) distribution of candidate K_L⁰->pi⁺pi^-gamma events, all other cuts applied. The cut on this quntity required events to be within the first bin (0.000250 GeV²/c²) on this plot.
  
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• egcom.eps, egcom.pdf
  FIG.3. K_L⁰->pi⁺pi^-gamma Monte Carlo/data overlay of photon energy distribution in the center of mass, for the rho-propagator fit result (Table I). Shown also (shaded) are the expected distributions for pure E1 inner Bremsstrahlung nd form-factor-modified M1 direct emission. The "combined" Monte Carlo plot shown assumes these two are the only contribution to the deay.
  
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• ffcomp.eps, ffcomp.pdf
  FIG.4. Ratio (points) of (IB-subtracted) direct-emission data to teh expectation for a pure M1 E^*_gamma spectrum. Vertical scale is arbitrary. Shown for comparison are the best-fit results (Table I) for the rho-propagator (solid), linear (dashed), and quadratic (dotted) form-factor parametrizations. A modification to the pure-M1 spectrum is clearly supported by the data.
  
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