"WW 2D limit plot" of "Search for high-mass exclusive $\gamma\gamma\to WW$ and $\gamma\gamma\to ZZ$ production in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

{Expected and observed limits in the two-dimensional plane of $a^W_0/\Lambda^2$ vs. $a^W_C/\Lambda^2$.
The limits are described by analytical ellipses of equation $(x-x0)^2/a^2 + (y-y0)^2/b^2 = 1$ and rotated counter-clockwise by $\theta$ degrees, where $x$ and $y$ in the equation correspond to the $a_0^W$ and $a_C^W$ couplings, respectively.