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Register a new userObservation of New States Decaying into $Lambda_c^+ K^-pi^+$ and $Lambda_c^+ K^0_Spi^-$
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We report the first observation of two charmed strange baryons that decay into $Lambda_c^+ K^-pi^+$. The broader of the two states is measured to have a mass of $2978.5pm 2.1pm 2.0$ MeV/$c^2$ and a width of $43.5pm 7.5pm 7.0$ MeV/$c^2$. The mass and width of the narrow state are measured to be $3076.7pm 0.9pm 0.5$ MeV/$c^2$ and $6.2pm 1.2pm 0.8$ MeV/$c^2$, respectively. We also perform a search for the isospin partner states that decay into $Lambda_c^+ K_S^0pi^-$ and observe a significant signal at the mass of $3082.8pm 1.8pm 1.5$ MeV/$c^2$. The data used for this analysis was accumulated at or near the $Upsilon(4S)$ resonance, using the Belle detector at the $e^+ e^-$ asymmetric-energy collider KEKB. The integrated luminosity of the data sample used is $461.5 ~mathrm{fb}^{-1}$.
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Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invariant mass of 596 +- 1 +- 2 MeV above the Lambda_c^+ mass. These results are preliminary.
The $Lambda_c^+K^-$ mass spectrum is studied with a data sample of $pp$ collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb$^{-1}$ collected by the LHCb experiment. Three $Xi_c^0$ states are observed with a large significance and their masses and natural widths are measured to be begin{eqnarray*} m(Xi_c(2923)^0)&=& 2923.04 pm 0.25 pm 0.20 pm 0.14 ~mathrm{MeV}, Gamma(Xi_c(2923)^0) &=& 7.1 pm 0.8 pm 1.8 ~mathrm{MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2939)^0) &=& 2938.55 pm 0.21 pm 0.17 pm 0.14 ~mathrm{ MeV}, Gamma(Xi_c(2939)^0) &=& 10.2 pm 0.8 pm 1.1 ~mathrm{ MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2965)^0) &=& 2964.88 pm 0.26 pm 0.14 pm 0.14~mathrm{ MeV}, Gamma(Xi_c(2965)^0) &=& 14.1 pm 0.9 pm 1.3~mathrm{ MeV}, end{eqnarray*} where the uncertainties are statistical, systematic, and due to the limited knowledge of the $Lambda_c^+$ mass. The $Xi_c(2923)^0$ and $Xi_c(2939)^0$ baryons are new states. The $Xi_c(2965)^0$ state is in the vicinity of the known $Xi_c(2970)^0$ baryon; however, their masses and natural widths differ significantly.
Using 567 $pb^{-1}$ of data collected with the BESIII detector at a center-of-mass energy of $sqrt{s}=$ 4.599 $GeV$, near the $Lambda_{c}^{+}Lambda_{c}^{-}$ threshold, we study the singly Cabibbo-suppressed decays $Lambda_c^{+}to ppi^{+}pi^{-}$ and $Lambda_c^{+}to pK^{+}K^{-}$. By normalizing with respect to the Cabibbo-favored decay $Lambda_c^{+}to pK^{-}pi^{+}$, we obtain ratios of branching fractions: $frac{mathcal{B}(Lambda_c^{+}to ppi^{+}pi^{-})}{mathcal{B}(Lambda_c^{+}to pK^{-}pi^{+})}$ = $(6.70 pm 0.48 pm 0.25)%$, $frac{mathcal{B}(Lambda_c^{+}to pphi)}{mathcal{B}(Lambda_c^{+}to pK^{-}pi^{+})}$ = $(1.81 pm 0.33 pm 0.13)%$, and $frac{mathcal{B}(Lambda_c^{+}to pK^{+}K^{-}_{text{non-}phi})}{mathcal{B}(Lambda_c^{+}to pK^{-}pi^{+})}$ = $(9.36 pm 2.22 pm 0.71)times10^{-3}$, where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay $Lambda_c^{+}to ppi^{+}pi^{-}$ is observed for the first time, and the precision of the branching fraction for $Lambda_c^{+}to pK^{+}K^{-}_{text{non-}phi}$ and $Lambda_c^{+}to pphi$ is significantly improved.
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 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.
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