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Title: Measurement of the K{sup 0} Charge Radius and a CP-Violating Asymmetry and a Search for CP-Violating E1 Direct Photon Emission in the Rare Decay K{sub L}{yields}{pi}{sup +}{pi}{sup -}e{sup +}e{sup -}

Abstract

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 determined a first experimental upper limit of 0.04 (90% C.L.) for the ratio (vertical bar g{sub E1} vertical bar/vertical bar g{sub M1} vertical bar) of the couplings for the E1 and M1 direct photon emission processes. We also report the measurement of vertical bar g{sub M1} vertical bar including a vector form factor vertical bar g-tilde{sub M1} vertical bar (1+(a{sub 1}/a{sub 2}/(M{sub {rho}}{sup 2}-M{sub K}{sup 2})+2M{sub K}E{sub {gamma}}{sub *})), where vertical bar g-tilde{sub M1} vertical bar =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}. Finally, a CP-violating asymmetry of [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{sub L} center of mass is reported.

Authors:
; ; ; ; ; ; ; ; ; ; ;  [1]; ; ; ; ; ; ; ;  [2]
  1. Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States)
  2. University of Virginia, Charlottesville, Virginia 22901 (United States) (and others)
Publication Date:
OSTI Identifier:
20777084
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevLett.96.101801; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; CENTER-OF-MASS SYSTEM; CP INVARIANCE; ELECTRONS; FORM FACTORS; KAONS NEUTRAL LONG-LIVED; PAIR PRODUCTION; PHOTON EMISSION; PIONS MINUS; PIONS PLUS; POSITRONS; SEMILEPTONIC DECAY; T INVARIANCE

Citation Formats

Abouzaid, E., Blucher, E., Glazov, A., Gomes, R.A., Kessler, R., Monnier, E., Solomey, N., Wah, Y.W., Winstein, B., Winston, R., Worchester, E.T., Worchester, M., Arenton, M., Corti, G., Cox, B., Golossanov, A., Ledovskoy, A., Nelson, K.S., Ronquest, M., and Shields, J.. Measurement of the K{sup 0} Charge Radius and a CP-Violating Asymmetry and a Search for CP-Violating E1 Direct Photon Emission in the Rare Decay K{sub L}{yields}{pi}{sup +}{pi}{sup -}e{sup +}e{sup -}. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.101801.
Abouzaid, E., Blucher, E., Glazov, A., Gomes, R.A., Kessler, R., Monnier, E., Solomey, N., Wah, Y.W., Winstein, B., Winston, R., Worchester, E.T., Worchester, M., Arenton, M., Corti, G., Cox, B., Golossanov, A., Ledovskoy, A., Nelson, K.S., Ronquest, M., & Shields, J.. Measurement of the K{sup 0} Charge Radius and a CP-Violating Asymmetry and a Search for CP-Violating E1 Direct Photon Emission in the Rare Decay K{sub L}{yields}{pi}{sup +}{pi}{sup -}e{sup +}e{sup -}. United States. doi:10.1103/PhysRevLett.96.101801.
Abouzaid, E., Blucher, E., Glazov, A., Gomes, R.A., Kessler, R., Monnier, E., Solomey, N., Wah, Y.W., Winstein, B., Winston, R., Worchester, E.T., Worchester, M., Arenton, M., Corti, G., Cox, B., Golossanov, A., Ledovskoy, A., Nelson, K.S., Ronquest, M., and Shields, J.. Fri . "Measurement of the K{sup 0} Charge Radius and a CP-Violating Asymmetry and a Search for CP-Violating E1 Direct Photon Emission in the Rare Decay K{sub L}{yields}{pi}{sup +}{pi}{sup -}e{sup +}e{sup -}". United States. doi:10.1103/PhysRevLett.96.101801.
@article{osti_20777084,
title = {Measurement of the K{sup 0} Charge Radius and a CP-Violating Asymmetry and a Search for CP-Violating E1 Direct Photon Emission in the Rare Decay K{sub L}{yields}{pi}{sup +}{pi}{sup -}e{sup +}e{sup -}},
author = {Abouzaid, E. and Blucher, E. and Glazov, A. and Gomes, R.A. and Kessler, R. and Monnier, E. and Solomey, N. and Wah, Y.W. and Winstein, B. and Winston, R. and Worchester, E.T. and Worchester, M. and Arenton, M. and Corti, G. and Cox, B. and Golossanov, A. and Ledovskoy, A. and Nelson, K.S. and Ronquest, M. and Shields, J.},
abstractNote = {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 determined a first experimental upper limit of 0.04 (90% C.L.) for the ratio (vertical bar g{sub E1} vertical bar/vertical bar g{sub M1} vertical bar) of the couplings for the E1 and M1 direct photon emission processes. We also report the measurement of vertical bar g{sub M1} vertical bar including a vector form factor vertical bar g-tilde{sub M1} vertical bar (1+(a{sub 1}/a{sub 2}/(M{sub {rho}}{sup 2}-M{sub K}{sup 2})+2M{sub K}E{sub {gamma}}{sub *})), where vertical bar g-tilde{sub M1} vertical bar =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}. Finally, a CP-violating asymmetry of [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{sub L} center of mass is reported.},
doi = {10.1103/PhysRevLett.96.101801},
journal = {Physical Review Letters},
number = 10,
volume = 96,
place = {United States},
year = {Fri Mar 17 00:00:00 EST 2006},
month = {Fri Mar 17 00:00:00 EST 2006}
}