Gravitational form-factors of the $π$ and $K$ mesons in QCD sum rules

Abstract: Taking into account only the quark part of the energy-momentum tensor, the gravitational form-factors of the $\pi$ and $K$ mesons are calculated within the light-cone sum rules method using the distribution amplitudes of these pseudoscalar mesons. The $Q²$-dependence of the relevant form-factors are obtained. Moreover, the mean square mass radii of $\pi$ and $K$ mesons are calculated and we find that $$\sqrt{\langle r_{\pi}² \rangle} = 0.31 {\rm\ fm}$$ and $$\sqrt{\langle r_{K}² \rangle} = 0.24 {\rm\ fm}$$, respectively. We compare our results for gravitational form-factors with the existing literature results. We obtain that our results on $\sqrt{\langle r_\pi² \rangle}$ are in good agreement with the predictions of NJL model, AdS/QCD model, and other models as well as with the existing experimental data.