Angular Distributions of B -> K ll Decays

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dc.creatorBobeth, Christoph
dc.creatorHiller, Gudrun
dc.creatorPiranishvili, Giorgi
dc.date2007-09-26
dc.date2007-12-13
dc.date.accessioned2026-07-07T11:37:32Z
dc.date.available2026-07-07T11:37:32Z
dc.descriptionWe model-independently analyze the angular distributions of B -> K ll 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 ~ 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 -> K mu mu to B -> K ee 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). The New Physics reach of the observables from the B -> K ll angular analysis is explored together with R_K and the B_s -> ll and B -> X_s ll 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 -> K mu mu angular distributions are suitable for the LHC environment and high luminosity B factories, where also studies of the electron modes are promising.
dc.description1 + 28 pages, 8 figures, uses JHEP3.cls; affiliation renamed, typos corrected, comments on electroweak corrections + 1 reference added
dc.identifierhttps://arxiv.org/abs/0709.4174
dc.identifierhttp://arxiv.org/abs/0709.4174
dc.identifierJHEP0712:040,2007
dc.identifierdoi:10.1088/1126-6708/2007/12/040
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/199237
dc.subjectHigh Energy Physics - Phenomenology
dc.titleAngular Distributions of B -> K ll Decays
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