KTeV KL>e e mu mu plots
Updated April 9, 2003.
[KL>eemumu Results]
Plots from
[PRL90 (2003)]
[PRL87 (2001)]
"Measurements of the Decay K_{L}>e^{+}e^{}mu^{+}mu^{}"

prl_conversion.epsi
Transverse electron hit separation at the first drift chamber versus M_{ee} for a) K_{L}>mu^{+}mu^{}gamma conversion Monte Carlo, b) signal Monte Carlo, and c) data. Plots are logarithmic in z. The box indicates the cut region.


final_mass_overlay.epsi
a) M_{eemumu} for all data (dots) and K_{L}> pipi^{}pi^{0}_{D} decay/punchthrough Monte Carlo (histogram) afterall cuts. 132 events remain in the signal region. The vertical lines indicate the expected signal region. b) Closeup of the signal mass region. The Monte Carlo is normalized to the integrated number of events in the data. The slight mismatch in a) between data and Monte Carlo is due to our misunderstanding of the pion punchthrough and pion decay processes.


fitalpha_br_tony.epsi
Simultaneous determination of the B(K_{L}> e^{+}e^{}mu^{+}mu^{}) and the DIP alpha parameter. The triangles show values for the branching ratio, based on 132 signal events with 0.8 background events. The error bars include statistical and systematic errors. The dots show the theoretical dependence of the branching ratio on alpha, where the errors result from the uncertainty in B(K_{L}>gamma gamma). The branching ratio and alpha are determined from the intersection of the two lines.


alpha_shape_compare.epsi
a) M_{mumu} and b) M_{ee} (right) distributions for the 132 signal events, compared to Monte Carlo generated with alpha = 1.51, 4.53. beta is zero for both overlays.


sincos.epsi
Angular distribution of the decay products for K_{L}>e^{+}e^{}mu^{+}mu^{} events (dots) and Monte Carlo with no CPviolation (histogram).

"Branching Ratio Measurement of the Decay
K_{L}>
e^{+}e^{}mu^{+}mu^{}"

paper_mass_nocuts_noroad.eps,
paper_mass_nocuts_noroad.pdf
Distribution of $M_{e e \mu\mu}$ after finding a fourtrack vertex and identifying two of the tracks as $e^{\pm}$ for data (hollow circles), and for Monte Carlo simulation of $K_L\rightarrow \pi^+\pi^\pi^0_D$ with charged pion punchthrough/decay at the same stage of analysis (dotted line). The simulation is normalized to the data below 0.32 GeV/c$^2$. The data distribution after cuts on vertex quality and any extra clusters in the calorimeter is shown by filled circles. A signal peak is visible at the kaon mass. At this stage of the analysis, $\sim$20\% of the events in that peak are $K_L\rightarrow \mu^+\mu^\gamma$ with $\gamma\rightarrow e^+e^$ in the vacuum window.


mvpt2_both_noroad.eps,
mvpt2_both_noroad.pdf
Top plot (a) shows $P_t^2$ vs. $M_{e e \mu\mu}$ for $K_L\rightarrow e^+e^\mu^+\mu^$, signal events, with all cuts. There are 43 events in the signal box. Bottom plot (b) shows same sign lepton events, $e^{\pm} e^{\pm}$ $\mu^{\mp} \mu^{\mp}$. There are no same sign events in the signal box. Note that the area in plot (b) is a factor of 10 larger than that in (a).


paper_allbckg_noroad.eps,
paper_allbckg_noroad.pdf
$M_{ee\mu\mu}$ for data (dots) and the scaled background simulation (line), with $P_t^2\leq 0.00025$ (GeV/c)$^2$. The peak resolution for the signal is approximately 4 MeV/$c^2$.


paper_formfact_noroad.eps,
paper_formfact_noroad.pdf
The distributions of $M_{ee}$ and $M_{\mu\mu}$ for the 43 events observed in the data (dots) as well as that expected from a model without any momentum dependent form factors (line).

Send comments/corrections to Taku