Electromagnetic form factors of $\Lambda_b$ in the Bethe-Salpeter   equation approach
  The heavy baryon $\Lambda_b $ is regarded as composed of a heavy quark and a scalar diquark which has good spin and isospin quantum numbers. In this picture, we calculate the electromagnetic (EM) form factors of $\Lambda_b$ in the Bethe-Salpeter equation approach. We find that the shapes of the EM form factors of $\Lambda_b$ are similar to those of $\Lambda$, which have a peak at about $\omega=1$, but the amplitudes are much smaller than those of $\Lambda$. 
Liang-Liang Liu, Chao Wang, Ying Liu, Xin-Heng Guo
hep-ph