$Λ_{c}(2910)$ and $Λ_{c}(2940)$ productions in $p \bar{p}$ annihilation

Abstract

In this work, we investigate the productions of $Λ_{c}(2910)$ and $Λ_{c}(2940)$ in the $p \bar{p} \rightarrow \barΛ_{c} D^{0} p$ process by utilizing an effective Lagrangian approach, where both $Λ_{c}(2910)$ and $Λ_{c}(2940)$ are considered as $D^{\ast}N$ molecular states with $J^{P}=1/2^{-}$ and $3/2^{-}$, respectively. In addition to the $t$-channel $D$ and $D^{\ast}$ exchanges, the contribution from light-meson exchange is also considered. At $\sqrt{s}=10$ $\mathrm{GeV}$, our estimations indicate that the total cross sections for $p \bar{p} \rightarrow \barΛ_{c} D^{0} p$ are $(130.7^{+397.1}_{-103.9})$ nb, where the central value is estimated with $Λ_{r}=1.1$ GeV, and the uncertainties are resulted from the variation of parameter $Λ_{r}$ from 1.0 GeV to 1.2 GeV. Our results indicate that the light meson exchange diagrams are very important, which provide a very large smooth background. Moreover, the estimations of the $D^{0}p$ invariant mass spectrum reveal that the peak structure between 2.9 and 3.0 GeV primarily originates from $Λ_c(2910)$, while the signal of $Λ_{c}(2940)$ is about one order smaller than that of $Λ_{c}(2910)$. Furthermore, the resulting Dalitz plot is estimated with $\sqrt{s}=8$ GeV. It is expected that our estimations in the present work can be tested by future experiments at $\mathrm{\bar{P}ANDA}$.

Figures (3)

• Figure 1: Diagrams contributing to the production of $\Lambda_c(2910)/\Lambda_c(2940)$ in the $p \bar{p} \rightarrow \bar{\Lambda}_{c} D^{0} p$ process. Diagrams (a) and (b) correspond to the $t$-channel light-meson and $D$ and $D^{\ast}$ exchanges, respectively. Here $\Lambda_{c}$ and $\Lambda^{\ast}_{c}$ refer to $\Lambda_{c}(2286)$ and $\Lambda_{c}(2910)/\Lambda_{c}(2940)$ states, respectively.
• Figure 2: (Color online.) The cross sections for the $p \bar{p} \rightarrow \bar{\Lambda}_{c} D^{0} p$ process depending on the center-of-mass energy $\sqrt{s}$. Diagram ($a$) corresponds to the individual contributions from light-meson and $\Lambda^{(\ast)}_{c}$ states, while Diagram ($b$) corresponds to the total cross sections with the uncertainty resulted from the model parameter $\Lambda_{r}$, where the black solid curve is obtained with $\Lambda_{r}=1.1$$\mathrm{GeV}$, and the cyan band represents the uncertainties resulted from the variation of $\Lambda_{r}$ from 1.0 to 1.2 $\mathrm{GeV}$.
• Figure 3: (Color online.) The Dalitz plot for $p \bar{p} \rightarrow \bar{\Lambda}_{c} D^{0} p$ process at $\sqrt{s}=8$$\mathrm{GeV}$ with $\Lambda_r=1.1$ GeV depending on $m_{D^0 p}$ and $m_{\bar{\Lambda}_c D^0}$ (diagram ($b$)). Diagrams ($a$) and ($c$) correspond to the $\bar{\Lambda}_{c} D^{0}$ and $D^{0}p$ invariant mass distributions, respectively.