Semileptonic decays of anti-triplet charmed baryons

Abstract

We study the semileptonic decays ${\mathbf{B}}_{\mathbf{c}}\to {\mathbf{B}}_{\mathbf{n}}{\ell }^{+}{\nu }_{\ell }$ where ${\mathbf{B}}_{\mathbf{c}(\mathbf{n})}$ is the anti-triplet-charmed (octet) baryon with the $SU(3{)}_f$ flavor symmetry and helicity formalism. In particular, we present the decay branching ratios of ${\mathbf{B}}_{\mathbf{c}}\to {\mathbf{B}}_{\mathbf{n}}{\ell }^{+}{\nu }_{\ell }$ in three scenarios: (a) an exact $SU(3{)}_f$ symmetry with equal masses for the anti-triplet-charmed (octet) baryon states of ${\mathbf{B}}_{\mathbf{c}}$ (${\mathbf{B}}_{\mathbf{n}}$), (b) $SU(3{)}_f$ parameters without the baryonic momentum-transfer dependence, and (c) $SU(3{)}_f$ with baryonic transition form factors in the heavy quark limit. We show that our results are all consistent with the existing data. Explicitly, we predict that $\mathcal{B}({\Xi }_c^{+}\to {\Xi }^0{e}^{+}{\nu }_e)=(11.9\pm 1.3,9.8\pm 1.1,10.7\pm 0.9)\times 10^{-2}$ and $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{e}^{+}{\nu }_e)=(3.0\pm 0.3,2.4\pm 0.3,2.7\pm 0.2)\times 10^{-2}$ in the scenarios (a), (b) and (c) agree with the data of $(14.0_{-8.7}^{+8.3})\times 10^{-2}$ and $(5.6\pm 2.6)\times 10^{-2}$ from the CLEO Collaboration, respectively. In addition, we obtain that $\mathcal{B}({\Lambda }_c^{+}\to n{e}^{+}{\nu }_e)=(2.8\pm 0.4,4.9\pm 0.4,5.1\pm 0.4)\times 10^{-3}$ in (a), (b) and (c). We also examine the longitudinal asymmetry parameters of $\alpha ({\mathbf{B}}_{\mathbf{c}}\to {\mathbf{B}}_{\mathbf{n}}{\ell }^{+}{\nu }_{\ell })$, which are sensitive to the different scenarios with $SU(3{)}_f$. Some of the decay branching ratios and asymmetries can be observed by the ongoing experiments at BESIII and LHCb as well as the future searches by BELLEII.

Comments: 11 pages, 1 figure, revised version accepted by PLB