Precise Measurement of the Ds plus Lifetime at Belle II

We measure the lifetime of the D-s(+) meson using a data sample of 207 fb(-1) collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e(+)e(- )collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116x10(3) D-s(+)->phi pi+ decays. Our result is tau(+)(Ds)=(499.5 +/- 1.7 +/- 0.9) fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Automated summary

In this study, we measured the lifetime of the D-s(+) meson using data collected by the Belle II experiment at the SuperKEKB collider. By fitting the decay-time distribution of D-s(+)->phi pi+ decays, we determined that the lifetime of the D-s(+) meson is tau(+)(Ds)=(499.5 +/- 1.7 +/- 0.9) fs, with improved precision compared to previous measurements.