Puzzles in charmed baryon semileptonic decays

Large apparent $SU(3{)}_F$ breaking and a tension with lattice QCD have recently emerged in semileptonic decays of singly charmed baryons, hinting at either an unexpected hadronic mechanism or new physics. We formulate a framework that systematically matches lattice-QCD inputs onto an $SU(3{)}_F$ analysis including first-order symmetry breaking. We predict $\mathcal{B}({\mathrm{\Xi }}_c^{+}\to {\mathrm{\Sigma }}^0{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }})\mathrm{/}\mathcal{B}({\mathrm{\Xi }}_c^{+}\to {\mathrm{\Xi }}^0{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }})=(2.6\pm 0.3)\mathrm{\%},$ and $\mathcal{B}({\mathrm{\Xi }}_c^{+}\to {\mathrm{\Lambda }}^0{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }})\mathrm{/}\mathcal{B}({\mathrm{\Xi }}_c^{+}\to {\mathrm{\Xi }}^0{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }})=(1.1\pm 0.1)\mathrm{\%}$, whose precise measurements would cleanly determine the origin of the anomalously large $SU(3{)}_F$ breaking.