Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays

Abstract

We present measurements of the Cabibbo-suppressed decays Lambda_c^+ --> Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+ --> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+ --> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy). Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+ K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams, are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+ and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-. This analysis was performed using 32.6 fb^{-1} of data collected by the Belle detector at the asymmetric e+ e- collider KEKB.

Submitted to Phys. Lett. B. v2: A small correction to the Authorlist was made. An earlier version of this analysis was released as BELLE-CONF-0130, hep-ex/0108003

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Cited by in corpus (32)

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• Theoretical study of the Xi(1620) and Xi(1690) resonances in Xi_c -> pi^+ MB decays
• First Observation of Doubly Cabibbo-Suppressed Decay of a Charmed Baryon: ${\Lambda }_c^{+}\to p{K}^{+}{\pi }^{-}$
• A Precision Measurement of the Lambda_c Baryon Mass
• The scalar $f_0(500)$ and $f_0(980)$ resonances and vector mesons in the single Cabibbo-suppressed decays ${\Lambda }_c\to p{K}^{+}{K}^{-}$ and $p{\pi }^{+}{\pi }^{-}$
• Roles of $a_0(980)$, $\Lambda (1670)$, and $\Sigma (1385)$ in the ${\Lambda }_c^{+}\to \eta \Lambda {\pi }^{+}$ decay
• Why $\Xi (1690)$ and $\Xi (2120)$ are so narrow?
• Role of high-spin hyperon resonances in the reaction of $\gamma p\to K^{+}{K}^{+}{\Xi }^{-}$
• $\Xi (1690)$ as a $\bar{K}\Sigma$ molecular state
• Prospects for Pentaquark Production at Meson Factories
• Measurements of the branching fractions of ${\Lambda }_c^{+}\to p{\pi }^{-}{\pi }^{+}$, ${\Lambda }_c^{+}\to p{K}^{-}{K}^{+}$, and ${\Lambda }_c^{+}\to p{\pi }^{-}{K}^{+}$
• Search for $CP$ violation and measurement of branching fractions and decay asymmetry parameters for ${\Lambda }_c^{+}\to \Lambda h^{+}$ and ${\Lambda }_c^{+}\to {\Sigma }^0{h}^{+}$ ($h=K,\pi$)
• Measurements of $\psi (3686)\to K^{-}\Lambda {\bar{\Xi }}^{+}+c.c.$ and $\psi (3686)\to \gamma K^{-}\Lambda {\bar{\Xi }}^{+}+c.c$
• The $a_0(980)$ in the single Cabibbo-suppressed process ${\Lambda }_c\to {\pi }^0\eta p$
• Measurement of the Branching Fraction of the Singly Cabibbo-Suppressed Decay ${\Lambda }_c^{+}\to \Lambda K^{+}$
• Measurements of ${\Lambda }_c^{+}$ Branching Fractions of Cabibbo-Suppressed Decay Modes involving $\Lambda$ and ${\Sigma }^0$
• 70 Years of Hyperon Spectroscopy: A review of strange $\Xi$, $\Omega$ baryons, and the spectrum of charmed and bottom baryons
• Measurements of ${\Xi }_c^{+}$ Branching Ratios
• Nonleptonic three-body charmed baryon weak decays with H(15)
• Measurement of Branching Fractions of Singly Cabibbo-suppressed Decays ${\Lambda }_c^{+}\to {\Sigma }^0{K}^{+}$ and ${\Sigma }^{+}{K}_S^0$
• Study ${\Xi }_c^{+}\to \Lambda {\bar{K}}^0{\pi }^{+}$ and search for the low-lying baryons $\Xi (1/2^{-})$ and $\Sigma (1/2^{-})$
• Study of Lambda/c+ Cabibbo Favored Decays Containing a Lambda Baryon in the Final State
• Measurements of Relative Branching Ratios of ${\Lambda }_c^{+}$ Decays into States Containing $\Sigma$
• First Observation of Cabibbo-Suppressed Ξ_c^0 Decays
• New Particles from Belle
• $\Xi (1690{)}^{-}$ production in the $K^{-}p\to K^{+}{K}^{-}\Lambda$ reaction process near threshold
• $\Xi (1690{)}^{-}$ resonance production via $K^{-}p\to K^{+}{K}^{-}\Lambda$
• Dynamically Generated $\Xi (1690)$
• Observation of the Singly Cabibbo-Suppressed Decay ${\Lambda }_c^{+}\to {\Sigma }^{-}{K}^{+}{\pi }^{+}$
• Monte Carlo Simulation-Based Partial Wave Analysis of ${\Xi }_c^{+}\to {\Xi }^{-}{\pi }^{+}{\pi }^{+}$ Decay