FCNC transitions of ${\Lambda }_b$ to neutron in Bethe-Salpeter equation approach

Abstract

In a covariant quark-diquark model, we investigate the rare decay of ${\Lambda }_b\to n{l}^{+}{l}^{-}$ and ${\Lambda }_b\to n\gamma$ in the Bethe-Salpeter equation approach. In this model the baryons are treated as bound states of a constituent quark and a diquark interacting via a gluon exchange and the linear confinement. We find that the ratio of form factors $R$ is varies from $-0.90$ to $-0.25$ and the branching ratios $Br({\Lambda }_b\to n{l}^{+}{l}^{-})\times 10^8$ are $6.79(l=e),4.08(l=\mu ),2.9(l=\tau )$ and the branching ratio $Br({\Lambda }_b\to \gamma )\times 10^7)=3.69$ in central values of parameters.

Comments: arXiv admin note: text overlap with arXiv:1911.08023