Three-body system of $\pi \pi \Sigma_c$

Understand

The existence of near-threshold charmed baryon $\Lambda_c(2595)^+$ implies that the pion and the lightest, isospin-$1$ charmed baryon $\Sigma_c$ interact very strongly at extremely low energies.

• Using the two-flavor version of heavy hadron chiral perturbation theory, I explore the direct consequences of this strong force by investigating whether the $\Sigma_c$ can trap two very soft pions to form any visible hadronic states.
• The answer is positive.
• It is found without tuning any free parameters or ultraviolet cutoff that the state in question, with quantum numbers $I(J^P) = 1({\frac{1}{2}}^+)$, presents itself as a resonance pole only a few MeVs away from the $\pi \pi \Sigma_c$ threshold.