Decay angles for the $ B ^0_ s \rightarrow \phi \phi$ decay, where the $K^+$ momentum in the $\phi_{1,2}$ rest frame, and the parent $\phi_{1,2}$ momentum in the rest frame of the $ B ^0_ s $ meson span the two $\phi$ meson decay planes, $\theta_{1,2}$ is the angle between the $K^+$ track momentum in the $\phi_{1,2}$ meson rest frame and the parent $\phi_{1,2}$ momentum in the $ B ^0_ s $ rest frame, $\Phi$ is the angle between the two $\phi$ meson decay planes and $\hat{n}_{1,2}$ is the unit vector normal to the decay plane of the $\phi_{1,2}$ meson.

Invariant $K^+K^-K^+K^-$ mass distribution for selected $ B ^0_ s \rightarrow \phi \phi$ candidates. A fit of a double Gaussian signal component together with an exponential background (dotted line) is superimposed.

Invariant mass distribution of $K^+K^-$ pairs for the $B^0_s \rightarrow \phi \phi$ data without a $\phi$ mass cut. The background has been removed using the $_{s}\mathcal{P}lot$ technique in conjunction with the $K^+K^-$ invariant mass. There are two entries per $B^0_s$ candidate. The solid line shows the result of the fit model described in the text. The fitted S-wave component is shown by the dotted line.

Angular distributions for (a) $\Phi$, (b) $\cos\theta_1$ and (c) $\cos\theta_2$ of $B_s^0 \rightarrow \phi \phi$ events with the fit projections for signal and background superimposed for the total fitted PDF (solid line) and background component (dotted line).

Distributions of the $U$ (left) and $V$ (right) observables for the $B_s^0 \rightarrow \phi \phi$ data in the mass range $5286.6 < M(K^+K^-K^+K^-) < 5446.6 \unit{MeV / {\it c}^2}$. The distribution for the background is taken from the mass sidebands, normalized to the same mass range and is shown by the solid histogram.

Animated gif made out of all figures.

Selection criteria for the $ B ^0_ s \rightarrow \phi \phi$ decay. The abbreviation IP stands for impact parameter and $ p_{\rm T} ^{\phi1}$ and $ p_{\rm T} ^{\phi2}$ refer to the transverse momentum of the two $\phi$ candidates.

Measured polarization amplitudes and strong phase difference. The uncertainties are statistical only. The sum of the squared amplitudes is constrained to unity. The correlation coefficient between ${|A_0|}^2$ and ${|A_{\perp}}|^2$ is $-0.47$.

Systematic uncertainties on the measured polarization amplitudes and the strong phase difference.

{} Systematic uncertainties on the triple product asymmetries $A_U$ and $A_V$. The total uncertainty is the quadratic sum of the larger of the two components.