Example of the OS correlation functions in individual $ N_{\text{VELO }}$ bins together with the global fit using Eq. 9 to parametrize the cluster contribution. The results are shown for (left) a moderate-multiplicity region ( $ 35 \leqslant N_{\text{VELO }} < 40 $ ) of the $ p $ {}Pb and (right) a high-multiplicity regime ( $ 100 \leqslant N_{\text{VELO }} < 115 $ ) of the Pb $ p $ dataset. Only statistical uncertainties are shown.

Example of fits to the SS correlation functions in (left) a moderate-multiplicity region ( $ 35 \leqslant N_{\text{VELO }} < 40 $ ) of the $ p $ {}Pb and (right) high-multiplicity regime ( $ 100 \leqslant N_{\text{VELO }} < 115 $ ) of the Pb $ p $ dataset. The black points correspond to the SS correlation functions , while the blue ones illustrate the OS correlation functions which are used to estimate the cluster contribution in the given $ N_{\text{VELO }}$ bin. The results of fits using Eq. 7 are indicated by red solid lines. Only statistical uncertainties are shown.

Correlation radius as a function of the reconstructed charged-particle multiplicity measured in the $ p $ $ p $ [52], $ p $ {}Pb and Pb $ p $ collision systems in the LHCb experiment. Error bars indicate the statistical uncertainties, while boxes illustrate the systematic ones. Data points are positioned at the centres of the multiplicity bins. Results of the fits to the observed radii scale linearly in the cube root of the reconstructed multiplicity (solid lines).

Intercept parameter as a function of the reconstructed charged-particle multiplicity measured in the $ p $ $ p $ [52], $ p $ {}Pb and Pb $ p $ collision systems in the LHCb experiment. Error bars indicate the statistical uncertainties, while boxes illustrate the systematic ones. Data points are positioned at the centres of the multiplicity bins.

Distribution of the selected signal pairs originating from primary vertices with the given VELO -track multiplicity in the $ p $ {}Pb (black dots) and Pb $ p $ (red circles) data.

Animated gif made out of all figures.

Ranges of the VELO -track multiplicity bins in the $ p $ {}Pb and Pb $ p $ datasets. An approximate fraction of the relevant data sample corresponding to the given bin is also indicated.

Results of the global fits to the OS correlation functions using Eq. 9 to parametrize the cluster contribution in the $ p $ {}Pb and Pb $ p $ data.

Systematic uncertainties on the $ R$ and $\lambda$ parameters. The listed ranges correspond to the lowest and highest values of the given input determined across most of the $ N_{\text{VELO }}$ bins in the $ p $ {}Pb and Pb $ p $ samples (see the description in text for details). Negligible contributions are not listed. The total uncertainty is a quadratic sum of the individual inputs.

Fractions of fake tracks in the selected pion sample and in the signal pairs (with $ Q$ values restricted to the $ Q < 1.0 \text{ Ge V} $ region) containing a fake track in the $ p $ {}Pb and Pb $ p $ datasets. The values are determined using the simulation.

Correlation parameters determined from fits to the SS correlation functions using Eq. 7 in the $ N_{\text{VELO }}$ bins for the $ p $ {}Pb and Pb $ p $ datasets. The first and second uncertainties are statistical and systematic, respectively.