Measurements of the decay KL-->e+ e- gamma

E Abouzaid; M Arenton; A R Barker; L Bellantoni; E Blucher; G J Bock; E Cheu; R Coleman; M D Corcoran; B Cox; A R Erwin; A Glazov; A Golossanov; Y B Hsiung; D A Jensen; R Kessler; H G E Kobrak; K Kotera; J LaDue; A Ledovskoy; P L McBride; E Monnier; H Nguyen; R Niclasen; E J Ramberg; R E Ray; M Ronquest; J Shields; W Slater; D Smith; N Solomey; E C Swallow; P A Toale; R Tschirhart; Y W Wah; J Wang; H B White; J Whitmore; M J Wilking; R Winston; E T Worcester; T Yamanaka; E D Zimmerman

doi:10.1103/PhysRevLett.99.051804

Measurements of the decay KL-->e+ e- gamma

Phys Rev Lett. 2007 Aug 3;99(5):051804. doi: 10.1103/PhysRevLett.99.051804. Epub 2007 Aug 3.

Affiliation

¹ The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637, USA.

PMID: 17930743
DOI: 10.1103/PhysRevLett.99.051804

Abstract

The E799-II (KTeV) experiment at Fermilab has collected 83 262 K(L)-->e+ e- gamma(gamma) events above a background of 79 events. We measure a decay width, normalized to the K(L)-->pi0pi0pi(D)0 (pi0-->gammagamma, pi0-->gammagamma, pi(D0-->e+ e- gamma(gamma)) decay width, of Gamma(K(L)-->e+e-gamma(gamma))/Gamma(K(L)-->pi0pi0pi(D)0)=(1.3302+/-0.0046(stat)+/-0.0102(syst)) x 10(-3). We also measure parameters of two K(L)gamma*gamma form factor models. In the Bergström-Massó-Singer parametrization, we find Calpha(K*)= -0.517 +/- 0.030(stat) +/- 0.022(syst). We separately fit for the first parameter of the D'Ambrosio-Isidori-Portolés model and find alpha(DIP)= -1.729 +/- 0.043(stat) +/- 0.028(syst).