Angular distributions of (B)over-bar→K(l)over-barl decays

We model-independently analyze the angular distributions of B -> K (l) over barl decays, l = e, mu, for low dilepton mass using QCD factorization. Besides the decay rate, we study the forward-backward asymmetry A(FB)(l) and a further observable, F-H(l), which gives rise to a flat term in the angular distribution. We find that in the Standard Model F-H(l) alpha m(l)(2), hence vanishing F-H(e) and F-H(mu) of around 2% (exact value depends on cuts) with a very small theoretical uncertainty of a few percent. We also give predictions for R-K, the ratio of (B) over bar -> K (mu) over bar mu to (B) over bar -> K (e) over bare decay rates. We analytically show using large recoil symmetry relations that in the Standard Model R-K equals one up to lepton mass corrections of the order 10(-4) including alpha(s) and subleading 1/E power corrections. The New Physics reach of the observables from the (B) over bar -> K (l) over barl angular analysis is explored together with R-K and the (B) over bar -> (l) over barl and (B) over bar -> X-s(l) over barl branching ratios for both l = e and l = mu. We find substantial room for signals from (pseudo-) scalar and tensor interactions beyond the Standard Model. Experimental investigations of the (B) over bar -> K (mu) over bar mu angular distributions are suitable for the LHC environment and high luminosity B factories, where also studies of the electron modes are promising.