New measurement of the properties of the rare decay K+ → π+e+e-

R. Appel, G. S. Atoyan, B. Bassalleck, D. R. Bergman, D. N. Brown, N. Cheung, S. Dhawan, H. Do, J. Egger, S. Eilerts, C. Felder, H. Fischer, M. Gach, W. Herold, V. V. Issakov, H. Kaspar, D. E. Kraus, D. M. Lazarus, L. Leipuner, P. LichardJ. Lowe, J. Lozano, H. Ma, W. Majid, W. Menzel, S. Pislak, A. A. Poblaguev, V. E. Postoev, A. L. Proskurjakov, P. Rehak, P. Robmann, A. Sher, T. L. Thomas, J. A. Thompson, P. Truöl, H. Weyer, M. E. Zeller

Research output: Contribution to journalArticlepeer-review

97 Scopus citations


A low-background sample of 10 300 events has been collected for the decay mode K+ → π+e+e- by experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The branching ratio is measured to be [2.94±0.05(stat)±0.13(syst)±0.05(model)]×10-7, the vector nature of this decay is firmly established, and the decay form factor f(z)=f0(1+δz)(z = M2ee/m2K) is determined to have δ = 2.14±0.13±0.15. The experiment is described and results discussed in the context of chiral perturbation theory.

Original languageEnglish
Pages (from-to)4482-4485
Number of pages4
JournalPhysical Review Letters
Issue number22
StatePublished - 1999


Dive into the research topics of 'New measurement of the properties of the rare decay K+ → π+e+e-'. Together they form a unique fingerprint.

Cite this