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KTeV Kl3 radiative decays plots

Updated November 10, 2004.

[Kl3 radiative decays Results]

Plots in Phys. Rev. D71, 012001 (2005)

"Measurements of the Branching Fraction and Decay Distributions for K_L-> pi^+-mu^-+nu gamma and K_L-> pi^+-e^-+nu gamma"

feyn_diag.eps, feyn_diag.pdf
FIG. 1: Feynman diagrams for the first-order radiative corrections to the K_l3 decay mode. Diagrams (a)-(f) are the virtual corrections while diagrams (g)-(i) are the innerbremsstrahlung corrections. The open circles in diagram (b) and (c) denote the self-energy correction to the pion and lepton wavefunctions, respectively.

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detector_noreg.eps, detector_noreg.pdf
FIG. 2: Plan view of the KTeV(E832) detector. The evacuated decay volume ends with a thin vacuum window at Z=159m. K_L decays from the two neutral beams are the source of semileptonic decays.

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csilayout.eps, csilayout.pdf
FIG. 3: Layout of CsI calorimeter. The small crystals (inner region have dimension 2.5 x 2.5 x 50 cm³. The two neutral beams go through the beam holes (into pagee) shown by the two inner squares. The fiducial cut, indicated by the dark lines, excludes radiated photons that hit a crystal near the beam holes or near the outer boundary.

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pp0kin_bkg.eps, pp0kin_bkg.pdf
FIG.4: k_+-0 distribution for (a) K_mu3gamma, and (b) K_e3gamma. Arrows indicate selected events for the K_l3gamma samples. Each peak at k_+-0 ~ 0 is background from K_L->pi⁺pi^-pi⁰ decays.

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csiadc.eps, csiadc.pdf
FIG. 5: For radiated photon cluster candidates in the K_e3gamma sample, (a) cluster energy deposit in RF bucket prior to event, and (b) cluster energy deposit in the first RF bucket. Energy is shown as ADC counts (1 ADC count i about 1 MeV). The arrow in each plot indicates the selected region.

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xbrem.eps, xbrem.pdf
FIG. 6: (a) Top view of spectrometer (DC1-4) and CsI calorimeter, and overlay of K_e3gamma decay. Delta R_gamma-brem is the distance between the photon candidate at the CsI and the location of the electron track projected from upstream of the magnet (dotted line); the latter is where a photon from external bremsstrahlung woudl hit the CsI. (b) Delta R_gamma-brem distribution for data (dots), for MC with radiated photons (dashed histogram). Plots are shown after K_e3gamma requirements. The arrow indicates the analysis selection.

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bkgkm3cm.eps, bkgkm3cm.pdf
FIG. 7: For K_L->pi^+-mu^-+nu gamma candidates without background subtraction, (a) minimum E^*_gamma and (b) maximum cos(theta^*_{gamma e}) for the tow kinematic solutions. Dots are data, and dashed histogram is the background predicted by the MC.

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bkgke3cm.eps, bkgke3cm.pdf
FIG. 8: For K_L->pi^+-e^-+nu gamma candidates without background subtraction, (a) minimum E^*_gamma and (b) maximum cos(theta^*_{gamma e}) for the tow kinematic solutions. Dots are data, and dashed histogram is the background predicted by the MC.

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brkm3rad_compare.eps, brkm3rad_compare.pdf
FIG. 9: Comparisons of R_Kmu3gamma among experiment and theory for (a) E^*_gamma > 10 MeV, and (b) E^*_gamma > 30 MeV. The experimental results are from KTeV and NA48. The thoery predictions are from Andre and from Fearing, Fischbach, and Smith, FFS. The FFS prediction is determined by NA48, and is corrected by (1 + delta^mu_K)^-1. The theory uncertainties are taken to be delta^mu_K = 0.019 times the prediction.

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brke3rad_compare.eps, brke3rad_compare.pdf
FIG. 10: Comparison of R_Ke3gamma among experiment and theory for (a)E^*_gamma > 10 MeV, and (b) E^*_gamma > 30 MeV and theta^*_{gamma e} > 20^o. The experimental results are from KTeV (this result and also KTeV 01), and NA31. The theory predictions are from Andre, Fearing, Fischbach, and Smith, FFS, Bijnens, and PHOTOTS. The FFS prediction is dtermined by Doncel and by KTeV, and each is corrected by (1 + delta^e_K)^-1. The theory uncertainties are taken to be delta^e_K = 0.013 times the prediction. The PHOTOS predictions fro one and two radiative photosn are described in Sec. VI B.

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km3cm.eps, km3cm.pdf
FIG. 11: Data-MC comparison of K_mu3gamma kinematics. For the two kaon energy solutions in the lab, (a) minimum radiated photon energy in kaon rest frame, and (b) maximum cosine of the photon-muon angle in kaon rest frame. Data are shown in dots; MC in histogram. The chi²/dof at the top of each plot refers to the data-MC comparison; data/MC ratios are shown in the lower plots. All K_mu3gamma selection requirements have been applied, and background is subtracted.

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ke3cm.eps, ke3cm.pdf
FIG. 12: Data-MC comparison of K_mu3gamma kinematics. For the two kaon energy solutions in the lab, (a) minimum radiated photon energy in kaon rest frame, and (b) maximum cosine of the photon-muon angle in kaon rest frame. Data are shown in dots; MC in histogram. The chi²/dof at the top of each plot refers to the data-MC comparison; data/MC ratios are shown in the lower plots. All K_e3gamma selection requirements have been applied.

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kmu4.eps, kmu4.pdf
FIG. 13: For the two kaon energy solutions, the invariant muon-neutrino mass closest to pion mass (m'_{mu nu}) is shown in (a) for data (dots) and MC K_L-> pi⁺pi^-pi⁰ (histogram). (b) shows the m'_{mu nu} distribution for MC K_L->pi⁰pi^+-mu^-+nu. The vertical lines show the selection window for K_L->pi⁰pi^+-mu^-+nu candidates. All K_L->pi⁰pi^+-mu^-+nu selection requirements, except for m'_{mu nu}, have been applied.

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k2pimip.eps, k2pimip.pdf
FIG. 14: For reconstructed K_L,S->pi⁺pi^- decays with an extra cluster that satisfies the K_l3gamma photon identification requiremetns, (a)pi-gamma separation at CsI (with separataion cut removed) and (b) photon eneryg distribution. Samples shown are data (dots), MC (histogram), and MC without pi-hadron interactions (sashed-histogram). The MC is normalized to the total numbers of K_L,S->pi⁺pi^- candidates.

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