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Register a new userMeasurement of the absolute branching fractions of $Lambda_{c}^{+}toLambdaetapi^{+}$ and $Sigma(1385)^{+}eta$
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We study the decays $Lambda_{c}^{+}toLambdaetapi^{+}$ and $Sigma(1385)^{+}eta$ based on $Lambda_{c}^{+}bar{Lambda}_{c}^{-}$ pairs produced in $e^+e^-$ collisions at a center-of-mass energy of $sqrt{s}=4.6~mbox{GeV}$, corresponding to an integrated luminosity of $567;mbox{pb$^{-1}$}$. The data sample was accumulated with the BESIII detector at the BEPCII collider. The branching fractions are measured to be $mathcal{B}(Lambda_{c}^{+} to Lambdaetapi^{+})=(1.84pm0.21({rm{stat.}})pm0.15({rm{syst.}}))%$ and $mathcal{B}(Lambda_{c}^{+} to Sigma(1385)^{+}eta)=(0.91pm0.18({rm{stat.}})pm0.09({rm{syst.}}))%$, constituting the most precise measurements to date.
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We report branching fraction measurements of four decay modes of the $Lambda_{c}^{+}$ baryon, each of which includes an $eta$ meson and a $Lambda$ baryon in the final state, and all of which are measured relative to the $Lambda_{c}^{+} rightarrow p K^{-} pi^{+}$ decay mode. The results are based on a $980~mathrm{fb^{-1}}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. Two decays, $eta Sigma^{0} pi^{+}$ and $Lambda(1670) pi^{+}$, are observed for the first time, while the measurements of the other decay modes, $Lambda_{c}^{+} rightarrow etaLambdapi^{+}$ and $etaSigma(1385)^{+}$, are more precise than those made previously. We obtain $mathcal{B}(Lambda_{c}^{+} rightarrow eta Lambda pi^{+})/mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = $0.293 pm 0.003 pm 0.014$, $mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma^{0} pi^{+})/mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = $0.120 pm 0.006 pm 0.006$, $mathcal{B}(Lambda_{c}^{+} rightarrow Lambda(1670) pi^{+}) times mathcal{B}(Lambda(1670) rightarrow eta Lambda)/mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = $(5.54 pm 0.29 pm 0.73 ) times 10^{-2}$, and $mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma(1385)^{+})/mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = $0.192 pm 0.006 pm 0.016$. The mass and width of the $Lambda(1670)$ are also precisely determined to be $1674.3 pm 0.8 pm 4.9~{rm MeV}/c^{2}$ and $36.1 pm 2.4 pm 4.8~{rm MeV}$, respectively, where the uncertainties are statistical and systematic, respectively.
Using $567rm{pb}^{-1}$ of $e^+e^-$ collisions recorded at $sqrt{s}=4.599rm{GeV}$ with the BESIII detector, we report first measurements of absolute hadronic branching fractions of Cabibbo-favored decays of the $Lambda_{c}^{+}$ baryon with a double-tag technique. A global least-square fitter is utilized to improve the measured precision. Among the measurements for twelve $Lambda_{c}^{+}$ decay modes, the branching fraction for $Lambda_{c}^{+} rightarrow pK^-pi^+$ is determined to be $(5.84pm0.27pm0.23)%$, where the first uncertainty is statistical and the second is systematic. In addition, the measurements of the branching fractions of the other eleven Cabbibo-favored hadronic decay modes are significantly improved.
Based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567$,rm{pb}^{-1}$ taken at the center-of-mass energy of $sqrt{s} = 4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay $Lambda_{c}^{+} to Lambda + X$ to be $mathcal{B}(Lambda_{c}^{+} to Lambda + X)=(38.2^{+2.8}_{-2.2}pm0.8)%$ using the double-tag method, where $X$ refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain $mathcal{A}_{CP} equiv frac{mathcal{B}(Lambda_{c}^{+} to Lambda + X)-mathcal{B}(bar{Lambda}_{c}^{-} to bar{Lambda} + X)}{mathcal{B}(Lambda_{c}^{+} to Lambda + X)+mathcal{B}(bar{Lambda}_{c}^{-} to bar{Lambda} + X)} = (2.1^{+7.0}_{-6.6}pm1.4)%$, a statistically limited result with no evidence of CP violation.
The ratios of the branching fractions of the decays $Lambda_{c}^{+} rightarrow p pi^{-} pi^{+}$, $Lambda_{c}^{+} rightarrow p K^{-} K^{+}$, and $Lambda_{c}^{+} rightarrow p pi^{-} K^{+}$ with respect to the Cabibbo-favoured $Lambda_{c}^{+} rightarrow p K^{-} pi^{+}$ decay are measured using proton-proton collision data collected with the LHCb experiment at a 7 TeV centre-of-mass energy and corresponding to an integrated luminosity of 1.0 fb$^{-1}$: begin{align*} frac{mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} pi^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} & = (7.44 pm 0.08 pm 0.18),%, frac{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} K^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} &= (1.70 pm 0.03 pm 0.03),%, frac{mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} K^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} & = (0.165 pm 0.015 pm 0.005 ),%, end{align*} where the uncertainties are statistical and systematic, respectively. These results are the most precise measurements of these quantities to date. When multiplied by the world-average value for $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$, the corresponding branching fractions are begin{align*} mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} pi^{+}) &= (4.72 pm 0.05 pm 0.11 pm 0.25) times 10^{-3}, mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} K^{+}) &= (1.08 pm 0.02 pm 0.02 pm 0.06) times 10^{-3}, mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} K^{+}) &= (1.04 pm 0.09 pm 0.03 pm 0.05) times 10^{-4}, end{align*} where the final uncertainty is due to $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$.
The branching fractions of D_s meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 /pb of e+ e- collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D_s decays with a double tag technique. In particular we determine the branching fraction B(D_s -> K- K+ pi+) = (5.50 +- 0.23 +- 0.16)%, where the uncertainties are statistical and systematic respectively. We also provide partial branching fractions for kinematic subsets of the K- K+ pi+ decay mode.
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