%0 Journal Article
%T (B)over-bar(s) -> K semileptonic decay from an Omnes improved constituent quark model
%A Albertus, C.
%A Hernandez, E.
%A Hidalgo-Duque, C.
%A Nieves, J.
%J Physics Letters B
%D 2014
%V 738
%I Elsevier Science Bv
%@ 0370-2693
%G English
%F Albertus_etal2014
%O WOS:000344624900022
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=2020), last updated on Thu, 25 Dec 2014 23:17:27 +0000
%X We study the f(+) form factor for the semileptonic (B) over bar (s) -> K+ l(-) (V) over bar (l) decay in a constituent quark model. The valence quark estimate is supplemented with the contribution from the (B) over bar* pole that dominates the high q(2) region. We use a multiply-subtracted Omnes dispersion relation to extend the quark model predictions from its region of applicability near q(max)(2) = (M-Bs – M-K)(2) similar to 23.75 GeV2 to all q(2) values accessible in the physical decay. To better constrain the dependence of f(+) on q(2), we fit the subtraction constants to a combined input from previous light cone sum rule by Duplancic and Melic (2008) [11] and the present quark model results. From this analysis, we obtain Gamma ( (B) over bar (s) -> K+ l(-) (V) over bar (l)) = (5.47(-0.46)(+0.54)) vertical bar Vub vertical bar(2) x 10(-9) MeV, which is about 10% and 20% higher than the predictions based on Lattice QCD and QCD light cone sum rules respectively. The former predictions, for both the form factor f(+) (q(2)) and the differential decay width, lie within the 1 sigma band of our estimated uncertainties for all q(2) values accessible in the physical decay, except for a quite small region very close to q(max)(2). Differences with the light cone sum results for the form factor f(+) are larger than 20% in the region above q(2) = 15 GeV2.
%R 10.1016/j.physletb.2014.09.037
%U http://arxiv.org/abs/1404.1001
%U https://doi.org/10.1016/j.physletb.2014.09.037
%P 144-149