Investigation of the effects of some new physics models in semileptonic Ξ _b and Ω _b decays

Abstract

Recent deviations from the standard model (SM) predictions of the experimental results on the R D ( * ) of the b → c l ν ̄ l semileptonic decay suggest the intervention of new physics (NP) mechanisms, which would affect the decay. Motivated by this, we investigate the possible NP effects on Ξ b → Ξ c τ ν ̄ τ and Ω b → Ω c τ ν ̄ τ processes in some NP models, such as the vector leptoquark (LQ) model, W′ model, aligned two-Higgs-doublet model and supersymmetry without R-parity model. Using the NP coupling parameter values obtained from different observables, we calculate various observables, such as the differential decay rate d B / d q 2 , the forward–backward asymmetry A FB l ( q 2 ) , the polarization fraction of final-state lepton and daughter baryon P L l ( q 2 ) as well as P L Ξ c ( Ω c ) ( q 2 ) , and the convexity parameter C F l ( q 2 ) in the SM and NP models. It is found that the SM predictions are consistent with those of previous works. In addition, the differential decay rate d B / d q 2 is quite sensitive to the contributions of some NP models. NP predictions generally show large deviations from the corresponding SM predictions. Nevertheless, the NP effects on some observables in the W′ model and LQ model are not sensitive, and these observables show the same variation tendency in the two NP models as in the SM.