Coupling constant for $\Lambda(1405)\bar{K}N$

Understand

The value of the $\Lambda(1405){\bar K}N$ coupling constant $g_{\Lambda(1405)\bar{K}N}$ is obtained by fitting it to the experimental data on the total cross sections of the $K^-p \to \pi^0\Sigma^0$ reaction.

• On the basis of an effective Lagrangian approach and isobar model, we show that the value $|g_{\Lambda(1405)\bar{K}N}| = 1.51 \pm 0.10$ could be extracted from the available experimental data by assuming that the $s-$channel $\Lambda(1405)$ resonance plays a dominant role, whereas, the background contributions from the $s-$channel $\Lambda(1115)$, $t-$channel $K^*$ and $u-$channel nucleon pole processes are small and can be neglected.
• However, the $u-$channel nucleon pole diagram may also give an important contribution in the present calculations.
• After the background contributions are taken into account, the above value of $g_{\Lambda(1405)\bar{K}N}$ is reduced to $|g_{\Lambda(1405)\bar{K}N}| = 0.77 \pm 0.07$, which is not supported by the previous calculations and the recent CLAS measurements.