Spectral ratio: an observable to determine $K^{+}$ nucleus potential and   $K^{+}$ N scattering cross section
  Here we aim to show that the ratio of the momentum spectra of $K^{+}$ at small transverse momentum measured for symmetric systems of different sizes can be such an observable. 
Aman D. Sood, Ch. Hartnack, and J\"org Aichelin
nucl-th