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Register a new userMeasurement of the absolute branching fraction of the inclusive decay $Lambda_c^+ to K_S^0X$
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We report the first measurement of the absolute branching fraction of the inclusive decay $Lambda_c^+ to K_S^0X$. The analysis is performed using an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ taken at $sqrt{s}$ = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored $bar{Lambda}_c^-$ decay modes and the double-tag technique, this absolute branching fraction is measured to be $mathcal{B}(Lambda_c^+ to K_S^0X)=(9.9pm0.6pm0.4)%$, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is $(18.7pm8.3)%$, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.
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Using a data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected at a center-of-mass energy of $sqrt{s}=4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic $Lambda_c^+$ decay with a double-tag method. We obtain $mathcal{B}(Lambda_c^+ rightarrow X e^+ u_e) = (3.95pm0.34pm0.09)%$, where the first uncertainty is statistical and the second systematic. Using the known $Lambda_c^+$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed measons ($D^0$ and $D^+$), we obtain the ratio of the inclusive semileptonic decay widths $Gamma(Lambda_c^+ rightarrow X e^+ u_e)/bar{Gamma}(Drightarrow X e^+ u_e)= 1.26pm0.12$.
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.
A measurement of the branching fraction of the decay $B_s^0 to K_S^0 K_S^0$ is performed using proton-proton collision data corresponding to an integrated luminosity of 5 $fb^{-1}$ collected by the LHCb experiment between 2011 and 2016. The branching fraction is determined to be BR($B_s^0 to K_S^0 K_S^0$) = [8.3 $pm$ 1.6 (stat) $pm$ 0.9 (syst) $pm$ 0.8 (norm) $pm$ 0.3 ($f_s/f_d$)] $times 10^{-6}$ , where the first uncertainty is statistical, the second is systematic, and the third and fourth are due to uncertainties on the branching fraction of the normalization mode $B^0 to phi K_S^0$ and the ratio of hadronization fractions $f_s/f_d$. This is the most precise measurement of this branching fraction to date. Furthermore, a measurement of the branching fraction of the decay $B^0 to K_S^0 K_S^0$ is performed relative to that of the $B_s^0 to K_S^0 K_S^0$ channel, and is found to be $frac{BR(B^0 to K_S^0 K_S^0)}{BR(B_s^0 to K_S^0 K_S^0)}$ = [7.5 $pm$ 3.1 (stat) $pm$ 0.5 (syst) $pm$ 0.3 ($f_s/f_d$)] $times 10^{-2}$.
We measure the inclusive semielectronic decay branching fraction of the $D_s^+$ meson. A double-tag technique is applied to $e^+e^-$ annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range $4.178 - 4.230$ GeV. We select positrons from $D_s^+rightarrow Xe^{+} u_e$ with momenta greater than 200 MeV/$c$, and determine the laboratory momentum spectrum, accounting for the effects of detector efficiency and resolution. The total positron yield and semielectronic branching fraction are determined by extrapolating this spectrum below the momentum cutoff. We measure the $D_s^+$ semielectronic branching fraction to be $mathcal{B}left(D_s^+rightarrow Xe^{+} u_eright)=left(6.30pm0.13;(text{stat.})pm 0.10;(text{syst.})right)%$, showing no evidence for unobserved exclusive semielectronic modes. We combine this result with external data taken from literature to determine the ratio of the $D_s^+$ and $D^0$ semielectronic widths, $frac{Gamma(D_{s}^{+}rightarrow Xe^+ u_e)}{Gamma(D^0rightarrow Xe^+ u_e)}=0.790pm 0.016;(text{stat.})pm0.020;(text{syst.})$. Our results are consistent with and more precise than previous measurements.
Using 980.6 $rm fb^{-1}$ of data collected with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we present a measurement of the branching fraction of the singly Cabibbo-suppressed decay $Lambda_c^+ to p omega$. A clear $Lambda_c^+$ signal is observed for $Lambda_c^+ to p omega$ with a statistical significance of 9.1 standard deviations, and we measure the ratio of branching fractions ${cal B}(Lambda_c^+ to p omega)/{cal B}(Lambda_c^+ to p K^- pi^+) = (1.32 pm 0.12 (rm stat) pm 0.10 (rm syst))times 10^{-2}$, from which we infer the branching fraction ${cal B}(Lambda_c^+ to p omega) = (8.27 pm 0.75 (rm stat) pm 0.62 (rm syst) pm 0.42 (rm ref))times 10^{-4}$. The first quoted uncertainty is statistical, the second systematic, and the third from the reference mode $Lambda_c^+ to p K^- pi^+$.
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