SU(2) HEAVY FLAVOUR SYMMETRY FOR B -> K(K^*) HADRONIC FORM FACTORS

Abstract

We show that the factorization assumption in colour-suppressed $B$ meson decays is not ruled out by experimental data on $B \ra K(K^*) + J/Ψ(Ψ^{'})$. The problem previously pointed out might be due to an inadequate choice of hadronic form factors. Within the Isgur-Wise SU(2) heavy flavour symmetry framework, we search for possible $q^2$-dependences of form factors that satisfy both the large longitudinal polarization $ρ_L$ observed in $B \ra K^* + J/Ψ$ and the relatively small ratio of rates $R_{J/Ψ} = Γ(B \ra K^* + J/Ψ)/Γ(B \ra K + J/Ψ)$. We find out that the puzzle could be essentially understood if the $A_1(q^2)$ form factor is frankly decreasing (instead of being almost constant or increasing as commonly assumed). Of course, the possibility of understanding experimental data is not necessarily a proof of factorization.