HFAG Rare B Compilation: Table 1, Line 14

Notes:
1) Similarly to the B=>Kππ (both charged and neutral) decays there is a substantial non-resonant component.
BaBar and Belle use several parametrizations for the non-resonant amplitude.
Good agreement with data is achieved with a simple exponential parameterization:

where s₁₃=M²(K⁺₁K^-), s₂₃=M²(K⁺₂K^-) and parameter &alpha, amplitudes a_i^nr and relative phases &delta_i^nr are free fit
parameters (&alpha=0.121+-0.014). See original paper(s) for more details.

2) Due to interplay between two various amplitudes (mainly S-wave amplitudes: f_X(1500)/X(1550) and non-resonant)
there are several sets of parameters exist that give (almost equally) good representation of the experimental data.
This feature seems to be common for all B=>KKK and B=>Kππ three-body modes. Further analysis is needed to
select one solution. See original paper(s) for more details.

References for the data:

Belle Collaboration:	Phys. Rev. D 71, 092003 (2005)
BaBar Collaboration:	Phys. Rev. D 74, 032003 (2006)

Some plots from references above: (for more details see original paper(s))

K⁺K^-_min invariant mass distributions:
K⁺K^-_max invariant mass distribution: