STEREO detection and selection efficiency for Phase-II and III. The efficiency is given in 22 antineutrino energy bins, bins 2-21 corresponding to the binning of the unfolded spectrum ranging 2.375-7.875 MeV, bin 1 integrates from 1.875 MeV to 2.375 MeV and bin 22 integrates from 7.875 MeV to 8.125 MeV.

STEREO Detector Response Matrix for Phase-II and III. The matrix is given as a 22x22 matrix, with 22 rows corresponding to the 22 bins of the prompt spectrum (1.625-7.125MeV) and 22 columns corresponding to 22 true antineutrino energy bins described with the efficiency vectors. Before use, the matrix should be normalized so that $\sum_j R_{ji} = \text{efficiency}_i$.

STEREO unfolded U-235 spectrum, given with 20 antineutrino energy bins (bins 1-19 are 250 keV wide, with centers ranging from 2.5 MeV to 7 MeV and bin 20 is 750 keV wide with center at 7.5 MeV). The prediction from Huber multiplied by the IBD cross section is also given.

Covariance matrix of the unfolded U-235 spectrum, given as a 20x20 matrix with 20 antineutrino energy bins (bins 1-19 are 250 keV wide, with centers ranging from 2.5 MeV to 7 MeV and bin 20 is 750 keV wide with center at 7.5 MeV).

Filter matrix associated with the Tikhonov-regularized unfolding. The filter matrix $A$ encodes all biases coming from the unfolding process itself. The matrix is given as a 22x22 matrix, bins 2-21 correspond to the 20 bins of the unfolded spectrum (2.375-7.875 MeV), bin 1 integrates from 1.875 MeV to 2.375 MeV, bin 22 integrates from 7.875 MeV to 8.125 MeV. It brings any model from true $E_\nu$ space to the filtered $E_\nu$ space where it can be compared to the unfolded spectrum $\Phi$, for instance with $\chi2 = (A \cdot \text{model} - \Phi)^T V_\Phi^{-1} (A\cdot \text{model} - \Phi)$. The unfolding process introduce very little biases so $A$ is close to diagonal.

STEREO IBD Spectrum in each cell for phase-II and phase-III. The spectra are given in nu/day with 11 500keV-wide measured-energy bins, ranging from 1.625MeV (lower edge of lowest bin) to 7.125 MeV (upper edge of highest bin), with statistical uncertainties. We also give the no-oscillation model after a common shape to all cells has been absorbed by the fitting procedure.

STEREO $\Delta\chi^2$ map (2D Feldman-Cousins method) obtained from STEREO data. $\Delta\chi^2$ is defined as $\Delta\chi^2 = \chi^2_\text{H0} - \chi^2_\text{min}$ with H0 the no-oscillation hypothesis. A $(\sin2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CL if $\Delta\chi^2 > \Delta\chi^2_{crit,n}$. To be used with the critical-$\Delta\chi^2$ map to obtain the 2D exclusion contour.

STEREO median $\Delta\chi^2$ map (2D Feldman-Cousins method) obtained from $10^4$ no-oscillation toys. $\Delta\chi^2$ is defined as $\Delta\chi^2 = \chi^2_\text{H0} - \chi^2_\text{min}$ with H0 the no-oscillation hypothesis. A $(\sin2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CL if $\Delta\chi^2 > \Delta\chi^2_{crit,n}$. To be used with the critical-$\Delta\chi^2$ map to obtain the 2D sensitivity contour.

STEREO $\Delta T$ map (CLs method) obtained from STEREO data. CLs is defined as $(1-p1)/(1-p0)$ with $p0$ [$p1$] the p-value from the $\Delta T$ p.d.f. obtained with toys following the no-oscillation $(0,0)$ [$(\sin 2\theta_{ee},\Delta m^2_{41})$] model. $\Delta T$ is defined as $\Delta T = \chi^2_\text{H1} - \chi^2_\text{H0}$ with H0 [H1] the no-oscillation hypothesis [the $(\sin 2\theta_{ee},\Delta m^2_{41})$ hypothesis]. A $(\sin 2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CL if $\Delta T > \Delta T_{crit,n}$. To be used with the critical $\Delta T$ map to obtain the CLs exclusion contour.

STEREO median $\Delta T$ map (CLs method) obtained from $5\times 10^3$ no-oscillation toys. CLs is defined as $(1-p1)/(1-p0)$ with $p0$ [$p1$] the p-value from the $\Delta T$ p.d.f. obtained with toys following the no-oscillation $(0,0)$ [$(\sin 2\theta_{ee},\Delta m^2_{41})$] model. $\Delta T$ is defined as $\Delta T = \chi^2_\text{H1} - \chi^2_\text{H0}$ with H0 [H1] the no-oscillation hypothesis [the $(\sin 2\theta_{ee},\Delta m^2_{41})$ hypothesis]. A $(\sin 2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CL if $\Delta T > \Delta T_{crit,n}$. To be used with the critical $\Delta T$ map to obtain the CLs sensitivity contour.

STEREO exclusion and sensitivity contours in the $(\sin 2\theta_{ee},\Delta m^2_{41})$ plane (2D Feldman-Cousins method).

STEREO exclusion and sensitivity contours in the $(\sin 2\theta_{ee},\Delta m^2_{41})$ plane (CLs method).

STEREO critical-$\Delta\chi^2$ map (2D Feldman-Cousins method) for 95%CL and 99%CL. A $(\sin2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CL if $\Delta\chi^2 > \Delta\chi^2_{crit,n}$. To be used with the $\Delta\chi^2$ maps obtained with STEREO data (exclusion) or with no-oscillation toys (sensitivity).

STEREO critical $\Delta T$ map (CLs method) for 95%CL and 99%CL. A $(\sin2\theta_{ee},\Delta m^2_{41})$ point is excluded at n%CLs if $\Delta T > \Delta T_{crit,n}$. To be used with the $\Delta T$ maps obtained with STEREO data (exclusion) or with no-oscillation toys (sensitivity).