Measurement of the Branching Fraction of the Singly Cabibbo-Suppressed Decay ${\Lambda }_c^{+}\to \Lambda K^{+}$

Abstract

We report a branching fraction measurement of the singly Cabibbo-suppressed decay ${\Lambda }_c^{+}\to \Lambda K^{+}$ using a data sample collected with the BESIII detector at the BEPCII storage ring. The data span center-of-mass energies from 4.599 to 4.950 GeV and correspond to an integrated luminosity of 6.44 fb${}^{-1}$. The branching fraction of ${\Lambda }_c^{+}\to \Lambda K^{+}$ relative to that of the Cabibbo-favored decay ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}$ is measured to be $\mathcal{R}=\frac{\mathcal{B}({\Lambda }_c^{+}\to \Lambda K^{+})}{\mathcal{B}({\Lambda }_c^{+}\to \Lambda {\pi }^{+})}=(4.78\pm 0.34\pm 0.20)\%$. Combining with the world-average value of $\mathcal{B}({\Lambda }_c^{+}\to \Lambda {\pi }^{+})$, we obtain $\mathcal{B}({\Lambda }_c^{+}\to \Lambda K^{+})=(6.21\pm 0.44\pm 0.26\pm 0.34)\times 10^{-4}$. Here the first uncertainties are statistical, the second systematic, and the third comes from the uncertainty of the ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}$ branching fraction. This result, which is more precise than previous measurements, does not agree with theoretical predictions, and suggests that non-factorizable contributions have been under-estimated in current models.

8 pages, 2 figures

References in corpus (6)

• Branching ratios and direct CP asymmetries in $D\to PP$ decays
• TopoAna: A generic tool for the event type analysis of inclusive Monte-Carlo samples in high energy physics experiments
• Charmed Baryon Physics Circa 2021
• Luminosities and energies of $e^{+}{e}^{-}$ collision data taken between $\sqrt{s}$=4.612 GeV and 4.946 GeV at BESIII
• Non-leptonic two-body weak decays of ${\Lambda }_c(2286)$
• Study of the Decays $D_s^{+}\to K_S^0{K}^{+}$ and $K_L^0{K}^{+}$

Cited by in corpus (5)

• Search for $CP$ violation and measurement of branching fractions and decay asymmetry parameters for ${\Lambda }_c^{+}\to \Lambda h^{+}$ and ${\Lambda }_c^{+}\to {\Sigma }^0{h}^{+}$ ($h=K,\pi$)
• First observation of ${\Lambda }_c^{+}\to \Lambda K^{+}{\pi }^0$ and evidence of ${\Lambda }_c^{+}\to \Lambda K^{+}{\pi }^{+}{\pi }^{-}$
• Measurement of the branching fractions of the decays ${\Lambda }_c^{+}\to \Lambda K_S^0{K}^{+}$, ${\Lambda }_c^{+}\to \Lambda K_S^0{\pi }^{+}$ and ${\Lambda }_c^{+}\to \Lambda K^{\ast +}$
• Prospects for $P$ and $CP$ violation in ${\Lambda }_c^{+}$ decays with polarized beam at Super Tau-Charm Facility
• Observation of the Singly Cabibbo-Suppressed Decay ${\Lambda }_c^{+}\to {\Sigma }^{-}{K}^{+}{\pi }^{+}$