Measurement of ${e}^{+}{e}^{-}\to {K}^{+}{K}^{-}$ cross section at $\sqrt{s}=2.00\text{}–\text{}3.08\text{}\text{}\mathrm{GeV}$

The cross section of the process ${e}^{+}{e}^{-}\to {K}^{+}{K}^{-}$ is measured at a number of center-of-mass energies $\sqrt{s}$ from 2.00 to 3.08 GeV with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The results provide the best precision achieved so far. A resonant structure around 2.2 GeV is observed in the cross section line shape. A Breit-Wigner fit yields a mass of $M=2239.2±7.1±11.3\text{}\text{}\mathrm{MeV}/{c}^{2}$ and a width of $\Gamma =139.8±12.3±20.6\text{}\text{}\mathrm{MeV}$, where the first uncertainties are statistical and the second ones are systematic. In addition, the timelike electromagnetic form factor of the kaon is determined at the individual center-of-mass energy points.