2017/01/15 by Hu, Quan-Yi, Li, Xin-Qiang, Yang, Ya-Dong
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.1701.04029
The rare baryonic decay Λb→ Λ(→ pπ-)μ+μ- provides valuable complementary information compared to the corresponding mesonic b→ sμ+μ- transition. In this paper, using the latest high-precision lattice QCD calculation of the Λb→Λ transition form factors, we study this interesting decay within the aligned two-Higgs-doublet model, paying particularly attention to effects of the chirality-flipped operators generated by the charged scalars. In order to extract the full set of angular coefficients in this decay, we consider the following ten angular observables that can be derived from the analysis of the subsequent parity-violating Λ→ pπ- decay: the differential branching fraction \rm d\cal B/\rm dq2, the longitudinal polarization fraction FL, the lepton-, hadron- and combined lepton-hadron-side forward-backward asymmetries A\rm FB^ℓ, A\rm FBΛ and A\rm FBℓΛ, as well as the other five asymmetry observables Yi~(i=\rm 2, 3s, 3sc, 4s, 4sc). Detailed numerical comparisons are made between the SM and NP values for these angular observables. It is found that, under the constraints from the inclusive B→ Xsγ branching fraction and the latest global fit results of b→ sℓℓ data, the contributions of right-handed semileptonic operators O′9,10, besides reconciling the P5′ anomaly observed in B0→ K∗ 0μ+μ- decay, could also enhance the values of \rm d\cal B/\rm dq2 and A\rm FB^ℓ in the bin [15,20]~\rm GeV2, leading to results consistent with the current LHCb measurements.