Fate of the charm baryon ${\Lambda }_c$ in cold and hot nuclear matter

Abstract

I discuss the properties of the ${\Lambda }_c$ baryon in nuclear matter at zero or finite temperature. Starting from the Lagrangian based on the heavy-quark effective theory, I derive the effective Lagrangian for the ${\Lambda }_c$ baryon existing as an impurity particle. Adopting the one-loop calculation for nucleons, I derive the effective potential as the quantity for measuring the stability of the ${\Lambda }_c$ baryon in nuclear matter. The parameters in the Lagrangian are fitted to reproduce the scattering length of the nucleon and the ${\Lambda }_c$ baryon estimated in the lattice QCD simulations and the chiral extrapolations. I present that the ${\Lambda }_c$ baryon is bound in nuclei with the binding energy of about 20 MeV at normal nuclear-matter density. I discuss the case that the ${\Lambda }_c$ baryon moves with a constant velocity. I also discuss an increase of the nucleon number density near the ${\Lambda }_c$ baryon in nuclear matter, and show that the ${\Lambda }_c$ baryon is a useful probe to research the nuclear systems at high density.

Comments: 17 pages, 6 figures