An Improved upper limit on the decay K^+ -> pi^+ mu^+ e^-

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

An Improved upper limit on the decay K^+ -> pi^+ mu^+ e^-

Authors

Description

Based on results of a search for the lepton-family-number-violating decay $K^+ \to π^+μ^+ e^-$ with data collected by experiment E865 at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, we place an upper limit on the branching ratio at $2.1 \times 10^{-11}$ (90% C.L.). Combining the results with earlier E865 data and those of a previous experiment, E777, an upper limit on the branching ratio of $1.3 \times 10^{-11}$ (90% C.L.) is obtained.
v2: 13 pages, submitted to the Phys. Rev. D v3: 13 pages, resubmitted to Phys. Rev. D (corrections include: a more detailed overview of the combined analysis of the available experimntal data)