Measurement of the absolute branching fraction of the inclusive decay $D_s^+\to \pi^+\pi^+\pi^- X$

TL;DR

This paper reports the first measurement of the inclusive decay branching fraction of the $D_s^+$ meson to final states with at least three charged pions, using data from the BESIII detector at 4.178 GeV.

Contribution

The study provides the first measurement of the inclusive $D_s^+ o ext{3 charged pions} + X$ branching fraction with detailed partial fractions as a function of invariant mass.

Findings

Branching fraction measured as (32.81 ± 0.35 (stat) ± 0.63 (syst))%.

Partial branching fractions as a function of $ ext{π}^+ ext{π}^+ ext{π}^-$ invariant mass.

Charged pions from $K_S^0$ decays are excluded.

Abstract

Using an $e^+ e^-$ collision data sample with a total integrated luminosity of $3.19$ fb$^{-1}$ collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the inclusive decay of the $D_s^+$ meson to final states including at least three charged pions is measured for the first time to be ${\cal B}(D_s^+\to\pi^+ \pi^+ \pi^- X) = (32.81 \pm 0.35_{\rm stat} \pm {0.63_{\rm syst}})\%$. In this measurement the charged pions from $K_S^0$ meson decays are excluded. The partial branching fractions of $D_s^+\to\pi^+ \pi^+ \pi^- X$ are also measured as a function of the $\pi^+ \pi^+ \pi^-$ invariant mass.