A Measurement Of The Branching Ratio Of The Pi 0 Dalitz Decay Using K Subscript L Arrow 3 Pi 0 Decays From Ktev

A Measurement of the Branching Ratio of the [pi]0 Dalitz Decay Using K[subscript]L [arrow] 3[pi]0 Decays from KTeV

A Measurement of the Branching Ratio of the [pi]0 Dalitz Decay Using K(L) 2!3 [pi]0 Decays from KTeV.

The authors present a measurement of B([pi]0 2!e+e-[gamma])/B([pi]0 2![gamma][gamma]) using data taken in 1999 by the E832 KTeV experiment at Fermilab. The [pi]0s were produced by KL decays in flight that are fully reconstructed. They find 63,693 KL 2!3[pi]0 2![gamma][gamma] [gamma][gamma] e+e-[gamma] decays in KTeV data (an increase of a factor of ~ 20 in event statistics over previous experiments), and normalize to KL 2!3[pi]0 2!6[gamma], to extract B([pi]0 2!e+e-[gamma], me+e-> 15 MeV/c2

Measuring the Branching Ratio of the Rare Decay Pi0 --] E+ E-

A precise branching ratio measurement of the rare decay {pi}{sup 0} {yields} e{sup +}e{sup -} has been made. The measurement was made with the rare kaon decay experiment KTeV at Fermilab where the source of {pi}{sup 0}s was K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sup 0} decaying in flight. A total of 794 fully reconstructed K{sub L} {yields} 3{pi}{sup 0} events consistent with two of the intermediate {pi}{sup 0}s decaying into {gamma}{gamma} and one into e{sup +}e{sup -} were collected. An estimated 53.2 {+-} 11.0 of these events were expected to be background. Normalizing to the {pi}{sup 0} Dalitz decay they found Br({pi}{sup 0} {yields} e{sup +}e{sup -}, (m{sub e{sup +}e{sup -}}/m{sub {pi}{sup 0}}){sup 2}> 0.95) = (6.44 {+-} 0.25(stat) {+-} 0.22(syst)) x 10{sup -8} where internal radiation, {pi}{sup 0} {yields} e{sup +}e{sup -}({gamma}), was limited by the requirement (m{sub e{sup +}e{sup -}}/m{sub {pi}{sup 0}}){sup 2}> 0.95 which separated it from the tree level Dalitz decay, {pi}{sup 0} {yields} e{sup +}e{sup -}P{gamma}.