Role of the Λ+c(2940) in the π- p → D- D⁰ p reaction close to threshold

الأصل · EN

We report on a theoretical study of the π- p → D- D⁰ p reaction near threshold within an effective Lagrangian approach. The production process is described by t channel D*⁰ meson exchange, s-channel nucleon pole, and u channel Σ⁺⁺c exchange. In our work, the final D⁰ p results from the ground Λ+c(2286) state and also dominantly from the excited Λ+c(2940) state which is assumed as a D*⁰ p molecular state with spin parity Jᵖ = 1/2+ or 1/2-. We calculate the total cross section of the π- p → D- D⁰ p reaction. It is shown that the spin parity assignment of 1/2- for Λ+c(2940) gives a sizable enhancement for the total cross section in comparison with a choice of Jᵖ = 1/2+. However, our theoretical result of the total cross section is sensitive to the value of the cutoff parameter involved in the form factor of the exchanged off-shell particles. Moreover, we also calculate the second order differential cross section and find it can be used to determine the parity of the Λ+c(2940). It is expected that our model calculations can be tested by future experiments at J-PARC in Japan.