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

作者：Bobeth Christoph^*; Hiller Gudrun; Piranishvili Giorgi

来源：The Journal of High Energy Physics, 2007, (12): 040.

DOI：10.1088/1126-6708/2007/12/040

• beyond standard model
• B-physics
• rare 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.

• 出版日期2007-12