Simultaneous measurement of KS and KL decays into π+π-γ

E. Ramberg, G. J. Bock, R. Coleman, J. Enagonio, Y. B. Hsiung, K. Stanfield, R. Tschirhart, T. Yamanaka, A. R. Barker, R. A. Briere, L. K. Gibbons, G. Makoff, V. Papadimitriou, J. R. Patterson, S. Somalwar, Y. W. Wah, B. Winstein, R. Winston, M. Woods, H. YamamotoE. C. Swallow, G. Blair, G. D. Gollin, M. Karlsson, J. K. Okamitsu, P. Debu, B. Peyaud, R. Turlay, B. Vallage

Research output: Contribution to journalArticlepeer-review


With the E731 apparatus at Fermilab, we have simultaneously collected 6859 KL and KS decays into π+π-γ. Using our sample of over 370 000 π+π- decays for normalization we have determined that the ratio Γ(K0→π+π-γ)/Γ(K0→π+π-) is (23.0±0.7)×10-3 for KL and (7.10±0.22)×10-3 for KS, for photon energies greater than 20 MeV in the kaon center of mass. After removing the inner-bremsstrahlung contribution, we find that the photon energy spectrum of the direct emission decay of the KL is consistent with the presence of a vector meson propagator in the form factor.

Original languageEnglish (US)
Pages (from-to)2525-2528
Number of pages4
JournalPhysical review letters
Issue number17
StatePublished - 1993
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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