No Arabic abstract
Based on 586 $rm{pb^{-1}}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy of $sqrt{s}=4.6~rm{GeV}$ with the BESIII detector at the BEPCII collider, the absolute branching fraction of $Lambda_c^+ to p K^0_{mathrm{S}}eta$ decays is measured for the first time to be $mathcal{B}(Lambda_c^+ to p K^0_{mathrm{S}}eta) = (0.414 pm 0.084 pm 0.028)%$, where the first uncertainty is statistical and the second is systematic. The result is compatible with a previous CLEO result on the relative branching fraction $frac{mathcal{B}(Lambda_c^+ to p K^0_{mathrm{S}}eta)}{mathcal{B}(Lambda_c^+ to p K^-pi^+)}$, and consistent with theoretical predictions of SU(3) flavor symmetry.
A search for the decay $K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}$ is performed using proton-proton collision data, corresponding to an integrated luminosity of $5.6,text{fb}^{-1}$ and collected with the LHCb experiment during 2016, 2017 and 2018 at a center-of-mass energy of $13,mathrm{TeV}$. The observed signal yield is consistent with zero, yielding an upper limit of ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.2 times 10^{-10}$ at 90% CL. The limit reduces to ${cal B}(K^0_{mathrm{S}}rightarrowmu^{+}mu^{-}) < 2.1 times 10^{-10}$ at 90% CL once combined with the result from data taken in 2011 and 2012.
We present the first model-independent measurement of the absolute branching fraction of the Lambda_c+ -> p K- pi+ decay using a data sample of 978 fb^-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The number of Lambda_c+ baryons is determined by reconstructing the recoiling D(*)- anti-p pi+ system in events of the type e+e- -> D(*)- anti-p pi+ Lambda_c+. The branching fraction is measured to be Br(Lambda_c+ -> p K- pi+) = (6.84 +- 0.24^{+0.21}_{-0.27})%, where the first and second uncertainties are statistical and systematic, respectively.
The charmless three-body decays $B^0_{(s)} to K_{mathrm{scriptscriptstyle S}}^0 h^+ h^{prime -}$ (where $h^{(prime)} = pi, K$) are analysed using a sample of $pp$ collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of $3mbox{fb}^{-1}$. The branching fractions are measured relative to that of the $B^0 to K_{mathrm{scriptscriptstyle S}}^0 pi^{+} pi^{-}$ decay, and are determined to be: begin{eqnarray*} frac{{cal B}(B^0rightarrow K^0_{rm S}K^{pm}pi^{mp})}{{cal B}(B^0rightarrow K^0_{rm S}pi^{+}pi^{-})} = {} & 0.123 pm 0.009 ; mathrm{,(stat)}; pm 0.015 ; mathrm{,(syst)},, frac{{cal B}(B^0rightarrow K^0_{rm S}K^{+}K^{-})} {{cal B}(B^0rightarrow K^0_{rm S}pi^{+}pi^{-})} = {} & 0.549 pm 0.018 ; mathrm{,(stat)}; pm 0.033 ; mathrm{,(syst)},, frac{{cal B}(B_{s}^0rightarrow K^0_{rm S}pi^{+}pi^{-})}{{cal B}(B^0rightarrow K^0_{rm S}pi^{+}pi^{-})} = {} & 0.191 pm 0.027 ; mathrm{,(stat)}; pm 0.031 ; mathrm{,(syst)}; pm 0.011 ; (f_s/f_d) ,, frac{{cal B}(B_{s}^0rightarrow K^0_{rm S}K^{pm}pi^{mp})} {{cal B}(B^0rightarrow K^0_{rm S}pi^{+}pi^{-})} = {} & 1.70phantom{0} pm 0.07phantom{0} ; mathrm{,(stat)} ; pm 0.11phantom{0} ; mathrm{,(syst)}; pm 0.10phantom{0} ; (f_s/f_d) ,, frac{{cal B}(B_{s}^0rightarrow K^0_{rm S}K^{+}K^{-})}{{cal B}(B^0rightarrow K^0_{rm S}pi^{+}pi^{-})} in {} & [0.008 - 0.051] rm ~at~90%~confidence~level, end{eqnarray*} where $f_s/f_d$ represents the ratio of hadronisation fractions of the $B^0_s$ and $B^0$ mesons.
We have searched for the Cabibbo-suppressed decay $Lambda_c^+tophi ppi^0$ in $e^+e^-$ collisions using a data sample corresponding to an integrated luminosity of 915 $rm fb^{-1}$. The data were collected by the Belle experiment at the KEKB $e^+e^-$ asymmetric-energy collider running at or near the $Upsilon(4S)$ and $Upsilon(5S)$ resonances. No significant signal is observed, and we set an upper limit on the branching fraction of $mathcal{B}(Lambda_c^+to phi ppi^0) <15.3times10^{-5}$ at 90% confidence level. The contribution for nonresonant $Lambda_c^+to K^+K^- ppi^0$ decays is found to be consistent with zero and the corresponding upper limit on its branching fraction is set to be $mathcal{B}(Lambda_c^+to K^+K^-ppi^0)_{rm NR} <6.3times10^{-5} $ at 90% confidence level. We also measure the branching fraction for the Cabibbo-favored decay $Lambda_c^+to K^-pi^+ppi^0$; the result is $mathcal{B}(Lambda_c^+to K^-pi^+ppi^0)= (4.42pm0.05, (rm stat.) pm 0.12, (rm syst.) pm 0.16, (mathcal{B}_{rm Norm}))%$, which is the most precise measurement to date. Finally, we have searched for an intermediate hidden-strangeness pentaquark decay $P^+_stophi p$. We see no evidence for this intermediate decay and set an upper limit on the product branching fraction of ${cal B}(Lambda_c^+to P^+_s pi^0)times {cal B}(P^+_stophi p) <8.3times 10^{-5}$ at 90% confidence level.
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.