KTeV KL>pi pi gamma plots
Updated August 29, 2006.
[KL>pi pi gamma Results]
Plots from
[PRD74 (2006)]
[PRL86 (2001)]

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+pigamma} cut. Crosses are data and the solid line is fit to the background components.


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


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.


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 (5shaded 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 (3dotted countour) of Ref. [7], for KTeV 1997 data (2dashed contour) in Ref.[5], and for KTeV 1997+1999 data (4solid contour) of Ref.[6], and for a1/a2 from earlier KTeV 96 K_{L}>pi^{+}pi^{}gamma data (1light gray vertical region) of Ref.[3].


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


belz0404fig7.eps,
belz0404fig7.pdf
magnetic dipole (M1) "Direct emission" (right) diagrams above.


linmas.eps,
linmas.pdf
FIG.2. (a) M_{pipig} distribution of cnadidate K_{L}^{0}>pi^{+}pi^{}gamma events, all other cuts applied. Arrows indicate final cuts at M_{k}+8 MeV/c^{2}.


logpt2.eps,
logpt2.pdf
(b) Kaon transverse momentum squared (P_{T}^{2}) distribution of candidate K_{L}^{0}>pi^{+}pi^{}gamma events, all other cuts applied. The cut on this quntity required events to be within the first bin (0.000250 GeV^{2}/c^{2}) on this plot.


egcom.eps,
egcom.pdf
FIG.3. K_{L}^{0}>pi^{+}pi^{}gamma Monte Carlo/data overlay of photon energy distribution in the center of mass, for the rhopropagator fit result (Table I). Shown also (shaded) are the expected distributions for pure E1 inner Bremsstrahlung nd formfactormodified M1 direct emission. The "combined" Monte Carlo plot shown assumes these two are the only contribution to the deay.


ffcomp.eps,
ffcomp.pdf
FIG.4. Ratio (points) of (IBsubtracted) directemission data to teh expectation for a pure M1 E^{*}_{gamma} spectrum. Vertical scale is arbitrary. Shown for comparison are the bestfit results (Table I) for the rhopropagator (solid), linear (dashed), and quadratic (dotted) formfactor parametrizations. A modification to the pureM1 spectrum is clearly supported by the data.

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