Abstract
We first study the charmless two-body Λb decays with scalar mesons as the final states and predict that B(Λb→Λf0(980,1500))=(2.9±0.7,12.4±3.8)×10-6 and B(Λb→pK0∗-(800,1430))=(1.9±0.5,14.1±4.5)×10-6. With the resonant f0(980,1500)→(π+π-,K+K-) and K0∗-→K̄0π- decays, we then obtain B(Λb→Λ(π+π-,K+K-))=(4.2±1.0,3.5±0.7)×10-6 and B(Λb→pK̄0π-)=(10.4±2.9)×10-6, in comparison with the data of (4.6±1.9,15.9±2.6)×10-6 and (12.6±4.0)×10-6, respectively, from LHCb. Our results for Λb→Λπ+π- and Λb→pK̄0π- would be regarded as the first evidence of scalar meson production in the antitriplet b baryon decays. The smaller predicted value of B(Λb→ΛK+K-) indicates the existence of other resonant contributions to the decay, such as Λb→K-(N∗+→)ΛK+.