Discover

Share

Download

News

/

Article

Long‐lived kaon shows no 2‐muon decay

JUL 01, 1971

DOI: 10.1063/1.3022837

Gloria B. Lubkin

The mysterious long‐lived K meson has produced another surprise. An experiment to look for $K_{L}^{0} {→μ}^{+} μ^{-}$ has failed to find any such decays and has established an upper limit to the branching ratio (for two‐muon decay compared to all decays) of ${1.82×10}^{−9},$ with a 90% confidence level. Straightforward theoretical estimates had predicted a branching ratio of about $10^{−8},$ but in any case a fairly plausible lower bound of ${6×10}^{−9},$ more than three times larger than the experimental upper limit. The experiment was done at the Berkeley Bevatron by Alan Clark, Tom Elioff, Clive Field, Henry Frisch, Rolland Johnson, Leroy Kerth and William Wenzel, all of Lawrence Radiation Laboratory, Berkeley (Phys. Rev. Lett., 28 June).

This article is only available in PDF format

© 1971 American Institute of Physics

Physics Today is looking for a Senior Editor. Apply Now.

Related content

News

/

Article

Kevin Ingles writes code for electrical engineering applications

January 23, 2026 12:35 PM

News

/

Article

FYI science policy briefs

January 16, 2026 10:38 AM

News

/

Article

The arXiv server to require English version with submissions

The availability of free translation software clinched the decision for the new policy. To some researchers, it’s anathema.

January 14, 2026 03:11 PM

News

/

Article

NASA’s next space telescope reaches assembly milestone

The Nancy Grace Roman Space Telescope will survey the sky for vestiges of the universe’s expansion.

January 12, 2026 11:26 AM

This Content Appeared In

Volume 24, Number 7

Get PT in your inbox

PT The Week in Physics

A collection of PT's content from the previous week delivered every Monday.

One email per week

PT New Issue Alert

Be notified about the new issue with links to highlights and the full TOC.

One email per month

PT Webinars & White Papers

The latest webinars, white papers and other informational resources.

1 to 2 emails per week