Exploring new physics in the C7-C7′ plane

The Wilson coefficient C-7 governing the radiative electromagnetic decays of B meson has been calculated to a very high accuracy in the Standard Model, but experimental bounds on either the magnitude or the sign of C-7 are often model-dependent. In the present paper, we attempt at constraining both the magnitude and sign of C-7 using a systematic approach. We consider already measured observables like the branching ratios of B -> X-s mu(+)mu(-) and B -> X-s gamma, the isospin and CP asymmetries in B -> K*gamma, as well as A(FB) and F-L in B -> K*l(+)l(-). We also discuss the transverse observable A(T)((2)) which, once measured, may help to disentangle some of the scenarios considered. We explore the constraints on C-7, C-9, C-10 as well as their chirality-flipped counterparts. Within our framework, we find that we need to extend the constraints up to 1.6 sigma to allow for the flipped-sign solution of C-7. The SM solution for C-7 exhibits a very mild tension if New Physics is allowed in dipole operators only. We provide semi-numerical expressions for all these observables as functions of the relevant Wilson coefficients at the low scale.