Strong decays of exotic and nonexotic heavy baryons in the chiral quark-soliton model

In the large $N_c$ limit both heavy and light baryons are described by the universal mean field, which allows us to relate the properties of heavy baryons to light ones. With the only input from the decays of light octet baryons (due to the universality of the chiral mean field), excellent description of strong decays of both charm and bottom sextets is obtained. The parameter-free prediction for the widths of exotic antidecapentaplet ($\overline{\mathbf{15}}$) baryons is also made. The exotic heavy baryons should be anomalously narrow despite the large phase space available. In particular, the widths of ${\mathrm{\Omega }}_c(3050)$ and ${\mathrm{\Omega }}_c(3119)$, interpreted as members of $\overline{\mathbf{15}}$-plet, are very small: 0.48 MeV and 1.12 MeV respectivly. This result is in very good agreement with the measurements of the LHCb Collaboration and provides natural and parameter-free explanation of the LHCb observation that ${\mathrm{\Omega }}_c(3050)$ and ${\mathrm{\Omega }}_c(3119)$ have anomalously small widths among five recently observed states.

Figure 1

Lowest lying SU(3) flavor representations allowed by the constraint $Y^{\prime }=2/3$. The first exotic representation, $\overline{\mathbf{15}}$ contains the putative pentaquark states ${\mathrm{\Omega }}_c$ with ${\mathrm{\Omega }}_c^0$ marked in red.

Figure 2

Decay widths of the charm baryons. Numbers on the horizontal axis label the decay modes as listed in Tables 1, 3, and 4. Red full circles correspond to our theoretical predictions. Dark green triangles correspond to the experimental data [41]. Data for decays 4–7 of ${\mathrm{\Sigma }}_c({\mathbf{6}}_1,3/2)$ (down triangles) have been divided by a factor of 5 to fit within the plot area. Widths of two LHCb [2] ${\mathrm{\Omega }}_c$ states that we interpret as pentaquarks are plotted as black full squares.

Figure 3

Decay widths of the bottom baryons. Numbers on the horizontal axis label the decay modes as listed in Table 2. Red full circles correspond to our theoretical predictions. Dark green triangles correspond to the experimental data [41]. Data for decays 6 and 7 of ${\mathrm{\Xi }}_b({\mathbf{6}}_1,3/2)$ (down triangles) have been multiplied by a factor of 5 to be better visible on the plot.