Analysis of Λ_b→pK^-and pπ^-decays in a flavor changing Z' mode

Abstract：

In this paper, we calculate the branching ratios of Λ _b→pK ^-and pπ ^-decays in the avor changing Z' model. We nd that the branching ratios for these two decay modes are sensitive to the contributions of the Z' boson. For Λ _b→pK ^-decay, if the left-handed couplings are equal to the right-handed couplings, the branching ratio of this decay could match up to the currently experimental data for ξ _s=0.01 and -52°< φ _s ^L<132°, or ξ _s=0.004 and 0°< φ _s ^L<84°; if only the left-handed couplings are considered, it could match up to the experimental data for ξ _s=0.01 and -10° φ _s ^L<138°. And for Λ _b→pK ^-decay, if the left-handed and right-handed couplings are equal, the branching ratio of Λ _b→pK ^-decay may be consistent with the currently experimental data with ξ _d=0.05 and -135° φ _d ^L<43°, if only the left-handed couplings are considered, it may be consistent with ξ _d=0.05 and -114° φ _d ^L<8°.