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arXiv · hep-ex/0305042

New, high statistics measurement of the K+ -> pi0 e+ nu (Ke3) branching ratio

A. Sher·R. Appel·G. S. Atoyan·B. Bassalleck·D. R. Bergman·N. Cheung·S. Dhawan·H. Do·J. Egger·S. Eilerts·H. Fischer·W. Herold·V. V. Issakov·H. Kaspar·D. E. Kraus·D. M. Lazarus·P. Lichard·J. Lowe·J. Lozano·H. Ma·W. Majid·S. Pislak·A. A. Poblaguev·P. Rehak·Aleksey Sher·J. A. Thompson·P. Truol·M. E. Zeller
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Abstract

E865 at the Brookhaven National Laboratory AGS collected about 70,000 K+(e3) events with the purpose of measuring the relative K+(e3) branching ratio. 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)) 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.

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A. Sher, R. Appel, G. S. Atoyan, B. Bassalleck, D. R. Bergman, N. Cheung, S. Dhawan, H. Do, J. Egger, S. Eilerts, H. Fischer, W. Herold, V. V. Issakov, H. Kaspar, D. E. Kraus, D. M. Lazarus, P. Lichard, J. Lowe, J. Lozano, H. Ma, W. Majid, S. Pislak, A. A. Poblaguev, P. Rehak, Aleksey Sher, J. A. Thompson, P. Truol, M. E. Zeller. 2004-07-12. New, high statistics measurement of the K+ -> pi0 e+ nu (Ke3) branching ratio. https://doi.org/10.1103/physrevlett.91.261802

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