Probing New Physics in b → d transitions

Recent experimental data on several observables in semileptonic B-meson decays are found to be in tension with the corresponding Standard Model predictions. Most of these deviations are related to b → c and b → s flavour changing transitions. In this work, we estimate possible New Physics effects in b → dμ+μ− flavour changing neutral currents. We parametrize NP contributions in a model-independent way and determine the allowed ranges of corresponding Wilson coefficients from the data on the exclusive B±→ π±μ+μ− decays measured recently by the LHCb collaboration. Afterwards, we investigate the impact of these results on other b → d processes such as the leptonic B0→ μ+μ− decays and B0−B¯0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\overline{B}}^0 $$\end{document} mixing. As an example, we consider a simplified Z′ model that is found to be consistent with current b → d data in the certain regions of the NP parameter space. In addition, we estimate the correlations between the partial decay widths of B → πμ+μ− and B → K μ+μ− processes to be used for an independent determination of CKM matrix elements as well as for a combined New Physics analysis of both b → d and b → s transitions.