Effects of neutron excess in deformed λ hypernuclei

The neutron excess effect, originating from the vanishing of one part of τ1·τ2 operator matrix elements, was appropriately considered within the Skyrme-type ΛNN three-body interactions and applied to the deformed SHF model. Analysis of a broad range of hypernuclei, from light to heavy masses, shows that the neutron excess effect significantly improves the description of Λ binding energies. The underlying mechanism involves reducing the ΛNN three-body repulsive interaction by subtracting the neutron excess term, thereby improving the binding energy of the hypernucleus. In addition, the impact of this effect on the Λ single-particle potential and the hyperon density distribution is discussed.