Resolving the low mass puzzle of $$\Lambda _c(2940)^+$$ Λc(2940)+

Abstract

Abstract For the long standing low mass puzzle of $$\Lambda _c(2940)^+$$ Λc(2940)+ , we propose an unquenched picture. Our calculation explicitly shows that the mass of the $$\Lambda _c(2P,3/2^-)$$ Λc(2P,3/2-) state can be lowered down to be consistent with the experimental data of $$\Lambda _c(2940)^+$$ Λc(2940)+ by introducing the $$D^*N$$ D∗N channel contribution. It means that the low mass puzzle of $$\Lambda _c(2940)^+$$ Λc(2940)+ can be solved. What is more important is that we predict a mass inversion relation for the 2P $$\Lambda _{c}^+$$ Λc+ states, i.e., the $$\Lambda _c(2P,1/2^-)$$ Λc(2P,1/2-) state is higher than the $$\Lambda _c(2P,3/2^-)$$ Λc(2P,3/2-) , which is totally different from the result of conventional quenched quark model. It provides a criterion to test such an unquenched scenario for $$\Lambda _c(2940)^+$$ Λc(2940)+ . We expect the future experimental progress from the LHCb and Belle II.