A Measurement of the K0 charge radius and a CP violating asymmetry together with a search for CP violating e1 direct photon emission in the rare decay K(L) ---> pi+ pi- e+ e-
Using the complete KTeV data set of 5241 candidate K{sub L} {yields} {pi}{sup +}{pi}{sup -}e{sup +}e{sup -} decays (including an estimated background of 204 {+-} 14 events), we have measured the coupling g{sub CR} = 0.163 {+-} 0.014 (stat) {+-} 0.023 (syst) of the CP conserving charge radius process and from it determined a K{sup 0} charge radius of <r{sub K{sup 0}}{sup 2}> = (-0.077 {+-} 0.007(stat) {+-} 0.011(syst))fm{sup 2}. We have also determined a first experimental upper limit of 0.04 (90% CL) for the ratio |g{sub E1}|/|g{sub M1}| of the coupling for the E1 direct photon emission process relative to the coupling for M1 direct photon emission process. We also report the measurement of |g{sub M1}| including its associated vector form factor |{bar g}{sub M1}|1 + a{sub 1}/a{sub 2}/(M{sub p}{sup 2} - M{sub K}{sup 2})+2M{sub K}E{sub {gamma}*} where |{bar g}{sub M1}| = 1.11 {+-} 0.12 (stat) {+-} 0.08 (syst) and a{sub 1}/a{sub 2} = (-0.744 {+-} 0.027 (stat) {+-} 0.032 (syst)) GeV{sup 2}/c{sup 2}. In addition, a measurement of the manifestly CP violating asymmetry of magnitude (13.6 {+-} 1.4 (stat) {+-} 1.5 (syst))% in the CP and T odd angle {phi} between the decay planes of the e{sup +}e{sup -} and {pi}{sup +}{pi}{sup -} pairs in the K center of mass system is reported.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 15020151
- Report Number(s):
- FERMILAB-PUB-05-355-E; arXiv eprint number hep-ex/0508010; TRN: US0602504
- Country of Publication:
- United States
- Language:
- English
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