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Register a new userEvidence for the singly-Cabibbo-suppressed decay $Lambda_{c}^{+} to peta$ and search for $Lambda_{c}^{+} to ppi^{0}$
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We study the singly-Cabibbo-suppressed decays $Lambda_c^{+}to peta$ and $Lambda_{c}^{+}to ppi^{0}$ using $Lambda_{c}^{+}Lambda_{c}^{+}$ pairs produced by $e^+e^-$ collisions at a center-of-mass energy of $sqrt{s} = 4.6; GeV$. The data sample was collected by the BESIII detector at the BEPCII collider and corresponds to an integrated luminosity of 567 $pb^{-1}$. We find the first evidence for the decay $Lambda_{c}^{+}to p eta$ with a statistical significance of $4.2sigma$ and measure its branching fraction to be $mathcal{B}(Lambda_c^+to peta)= (1.24pm0.28({rm{stat.}})pm0.10({rm{syst.}}))times10^{-3}$. No significant $Lambda_c^+ to ppi^0$ signal is observed. We set an upper limit on its branching fraction $mathcal{B}(Lambda_c^+ to ppi^{0}) < 2.7 times 10^{-4}$ at the 90% confidence level.
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A search for the flavor-changing neutral-current decay $Lambda_{c}^{+} to pmu^+mu^-$ is reported using a data set corresponding to an integrated luminosity of $3.0rm fb^{-1}$ collected by the LHCb collaboration. No significant signal is observed outside of the dimuon mass regions around the $phi$ and $omega$ resonances and an upper limit is placed on the branching fraction of $mathcal{B} (Lambda_{c}^{+} to pmu^+mu^-) < 7.7~(9.6)times 10^{-8}~{rm at}~90%~(95%)$ confidence level. A significant signal is observed in the $omega$ dimuon mass region for the first time.
Based on 2.93 fb$^{-1}$ $e^+e^-$ collision data taken at center-of-mass energy of 3.773 GeV by the BESIII detector, we report searches for the singly Cabibbo-suppressed decays $D^{+}toomegapi^{+}$ and $D^{0}toomegapi^{0}$. A double tag technique is used to measure the absolute branching fractions $mathcal{B}(D^{+}toomegapi^{+})=(2.79pm0.57pm0.16)times 10^{-4}$ and $mathcal{B}(D^{0}toomegapi^{0})=(1.17pm0.34pm0.07)times 10^{-4}$, with statistical significances of $5.5sigma$ and $4.1sigma$, respectively. We also present measurements of the absolute branching fractions for the related $eta pi$ decay modes. We find $mathcal{B}(D^{+}toetapi^{+})=(3.07pm0.22pm0.13)times10^{-3}$ and $mathcal{B}(D^{0}toetapi^{0})=(0.65pm0.09pm0.04)times10^{-3}$, which are consistent with the current world averages. The first and second uncertainties are statistical and systematic, respectively.
A search for previously unobserved decays of beauty baryons to the final states $K^0_{mathrm{S}}ppi^-$ and $K^0_{mathrm{S}}pK^-$ is reported. The analysis is based on a data sample corresponding to an integrated luminosity of $1.0,mathrm{fb}^{-1}$ of $pp$ collisions. The $Lambda^0_b rightarrow K^0_{mathrm{S}}ppi^-$ decay is observed for the first time with a significance of $8.6,sigma$, and a measurement is made of the $CP$ asymmetry, which is consistent with zero. No significant signals are seen for $Lambda^0_b rightarrow K^0_{mathrm{S}}pK^-$ decays, $Xi^0_b$ decays to both $K^0_{mathrm{S}}ppi^-$ and $K^0_{mathrm{S}}pK^-$ final states, and the $Lambda^0_b rightarrow D^-_s (K^0_{mathrm{S}}K^-)p$ decay, and upper limits on their branching fractions are reported.
We report evidence for the charged charmed-strange baryon $Xi_{c}(2930)^+$ with a signal significance of 3.9$sigma$ with systematic errors included. The charged $Xi_{c}(2930)^+$ is found in its decay to $K_{S}^{0} Lambda_{c}^+$ in the substructure of $bar{B}^{0} to K^{0}_{S} Lambda_{c}^{+} bar{Lambda}_{c}^{-}$ decays. The measured mass and width are $[2942.3 pm 4.4 (rm stat.) pm 1.5(rm syst.)]$~MeV/$c^{2}$ and $[14.8 pm 8.8(rm stat.) pm 2.5(rm syst.)]$~MeV, respectively, and the product branching fraction is $cal{B}(bar{B}^{0} to Xi_c(2930)^{+} bar{Lambda}_{c}^{-}) cal{B}(Xi_c(2930)^{+}to bar{K}^{0} Lambda_{c}^{+})=[2.37 pm 0.51 (rm stat.)pm 0.31(rm syst.)]times 10^{-4}$. We also measure $cal{B}(bar{B}^{0} to bar{K}^{0} Lambda_{c}^{+} bar{Lambda}_{c}^{-}) = [3.99 pm 0.76(rm stat.) pm 0.51(rm syst.)] times 10^{-4}$ with greater precision than previous experiments, and present the results of a search for the charmonium-like state $Y(4660)$ and its spin partner, $Y_{eta}$, in the $Lambda_{c}^{+}bar{Lambda}_{c}^{-}$ invariant mass spectrum. No clear signals of the $Y(4660)$ or $Y_{eta}$ are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $(772pm11)times 10^{6} Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
The doubly Cabibbo-suppressed decay $Xi_{c}^{+}to pphi$ with $phito K^{+}K^{-}$ is observed for the first time, with a statistical significance of more than fifteen standard deviations. The data sample used in this analysis corresponds to an integrated luminosity of 2 fb$^{-1}$ recorded with the LHCb detector in $pp$ collisions at a centre-of-mass energy of 8 TeV. The ratio of branching fractions between the decay $Xi_{c}^{+}to pphi$ and the singly Cabibbo-suppressed decay $Xi_{c}^{+}to pK^{-}pi^{+}$ is measured to be begin{equation*} frac{mathcal{B}(Xi_{c}^{+}to pphi)}{mathcal{B}(Xi_{c}^{+}to pK^{-}pi^{+})} = (19.8 pm 0.7 pm 0.9 pm 0.2) times 10^{-3}, end{equation*} where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the $phito K^{+}K^{-}$ branching fraction.
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