Precise measurement of Br(tau^- -> K^*0(892) K^- nu_tau) and the mass and width of the K^*0(892) meson

TL;DR

This paper reports precise measurements of the branching fraction, mass, and width of the K^*0(892) meson using high-statistics tau decay data from the Belle experiment, improving accuracy over previous values.

Contribution

The study provides the most precise measurements to date of the K^*0(892) meson parameters and reports the first measurement of a rare tau decay mode involving K^*0(892).

Findings

Branching fraction of tau^- -> K^*0(892) K^- nu_tau is (1.56+-0.02+-0.09)x10^-3.

Mass of K^*0(892) meson is (895.10+-0.27+-0.31) MeV/c^2.

Width of K^*0(892) meson is (47.23+-0.49+-0.79) MeV/c^2.

Abstract

Using the high statistics tau data sample recorded in the Belle experiment at KEKB, we have greatly improved the precision of the branching fraction Br(tau^- -> K^*0(892) K^- nu_tau) = (1.56+-0.02+-0.09)x10^-3, while the mass and width of the K^*0(892) meson are measured to be (895.10+-0.27+-0.31) MeV/c^2 and (47.23+-0.49+-0.79) MeV/c^2, respectively, with better accuracy than the PDG world average values. The first measurement of the decay tau^- -> K^*0(892) K^- pi^0 nu_tau is also reported with a branching fraction of Br(tau^- -> K^*0(892) K^- pi^0 nu_tau)=(2.39+-0.46+-0.26)x10^-5.