Precision measurement of the $e^{+}e^{-}~\rightarrow~\Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ cross section near threshold

Understand

The Born cross section of the $e^{+}e^{-}~\rightarrow~\Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ process is measured with unprecedented precision using data collected with the BESIII detector at $\sqrt{s}=4574.5$, $45580.0$, $4590.0$ and $4599.5$ $\mathrm{MeV}$.

• The non-zero cross section near the $\Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ production threshold is discerned.
• At center-of-mass energies $\sqrt{s}=4574.5$ and $4599.5 $ $\mathrm{MeV}$, the higher statistics data enable us to measure the $\Lambda_{c}$ polar angle distributions.
• From these, the ratio between the $\Lambda_{c}$ electric and magnetic form factors ($|G_{E}/G_{M}|$) is measured for the first time.