English

K+ -> pi0 e+ nu branching ratio from E865

High Energy Physics - Experiment 2007-05-23 v1

Abstract

E865 at the Brookhaven National Laboratory AGS collected about 70,000 K+(e3) events to measure the K+(e3) branching ratio relative to the observed K+ -> pi+ pi0, K+ -> pi0 mu+ nu, and K+ -> pi+ pi0 decays. The pi0 in all the decays was detected using the e+e- pair from pi0 -> e+e-gamma decay and no photons were required. Using the Particle Data Group branching ratios for the normalization decays we obtain BR(K+(e3(gamma))=(5.13+/-0.02(stat)+/-0.09(sys)+/-0.04(norm))%, where K+(e3(gamma))includestheeffectofvirtualandrealphotons.Thisresultis2.3sigmahigherthanthecurrentParticleDataGroupvalue.TheimplicationsofthisresultfortheK+(e3(gamma)) includes the effect of virtual and real photons. This result is 2.3 sigma higher than the current Particle Data Group value. The implications of this result for the V_{us}$ element of the CKM matrix, and the matrix's unitarity are discussed.

Keywords

Cite

@article{arxiv.hep-ex/0405036,
  title  = {K+ -> pi0 e+ nu branching ratio from E865},
  author = {A. A. Poblaguev},
  journal= {arXiv preprint arXiv:hep-ex/0405036},
  year   = {2007}
}

Comments

6 pages, 4 figures, Contribution to the Proceeding of the XXXIX Rencontres de Moriond on Electroweak Interactions and Unified Theories, LaThuile, Italy, 21-28 Mar 2004