Measurements of Absolute Hadronic Branching Fractions of the ${\mathrm{\Lambda }}_c^{+}$ Baryon

We report the first measurement of absolute hadronic branching fractions of ${\mathrm{\Lambda }}_c^{+}$ baryon at the ${\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}$ production threshold, in the 30 years since the ${\mathrm{\Lambda }}_c^{+}$ discovery. In total, 12 Cabibbo-favored ${\mathrm{\Lambda }}_c^{+}$ hadronic decay modes are analyzed with a double-tag technique, based on a sample of $567{\mathrm{pb}}^{-1}$ of $e^{+}{e}^{-}$ collisions at $\sqrt{s}=4.599\mathrm{GeV}$ recorded with the BESIII detector. A global least-squares fitter is utilized to improve the measured precision. Among the measurements for twelve ${\mathrm{\Lambda }}_c^{+}$ decay modes, the branching fraction for ${\mathrm{\Lambda }}_c^{+}\to p{K}^{-}{\pi }^{+}$ is determined to be $(5.84\pm 0.27\pm 0.23)\%$, where the first uncertainty is statistical and the second is systematic. In addition, the measurements of the branching fractions of the other 11 Cabibbo-favored hadronic decay modes are significantly improved.

Figure 1

Fits to the ST $M_{\mathrm{BC}}$ distributions in data for the different decay modes. Points with error bars are data, solid lines are the sum of the fit functions, and dashed lines are the background shapes.

Figure 2

Fits to the DT $M_{\mathrm{BC}}$ distributions in data for different signal modes. Points with error bars are data, solid lines are the sum of fit functions, and dashed lines are background shapes.