Published January 1, 2024
| Version v1
Journal article
Open
Search for lepton-flavor-violating τ<i><SUP>-</SUP>→</i> μ<i><SUP>-</SUP></i>μ<SUP>+</SUP>μ<i><SUP>-</SUP></i> decays at Belle II
Description
We present the result of a search for the charged-lepton-flavor violating decay tau(-) -> mu(-)mu(+)mu(-) using a 424 fb(-1) sample of data recorded by the Belle II experiment at the SuperKEKB e(+)e(-) collider. The selection of e(+)e(-) -> tau(+)tau(-) events is based on an inclusive reconstruction of the non-signal tau decay, and on a boosted decision tree to suppress background. We observe one signal candidate, which is compatible with the expectation from background processes. We set a 90% confidence level upper limit of 1.9 x 10(-8) on the branching fraction of the tau(-)-> mu(-)mu(+)mu(-) decay, which is the most stringent bound to date.
Files
bib-342e3881-dc22-494b-acd3-215c3575d0cf.txt
Files
(446 Bytes)
| Name | Size | Download all |
|---|---|---|
|
md5:7a034448adc002dd93acf54c28692270
|
446 Bytes | Preview Download |