FCNC transitions of $$\Lambda _b$$ to neutron in Bethe–Salpeter equation approach

Abstract

AbstractIn a covariant quark–diquark model, we investigate the rare decay of $$\Lambda _b \rightarrow n l^+ l^-$$Λb→nl+l- and $$\Lambda _b \rightarrow n \gamma $$Λb→nγ 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 $$-0.90$$-0.90 to $$-0.25$$-0.25 and the branching ratios $$Br(\Lambda _b \rightarrow n l^+ l^-)\times 10^{8}$$Br(Λb→nl+l-)×108 are $$6.79(l=e),~4.08 ~ (l=\mu ),~2.9 ~(l=\tau ) $$6.79(l=e),4.08(l=μ),2.9(l=τ) and the branching ratio $$Br(\Lambda _b \rightarrow n \gamma )\times 10^{7} )=3.69$$Br(Λb→nγ)×107)=3.69 in central values of parameters.