Corrigendum to “Search for a common baryon source in high-multiplicity pp collisions at the LHC” [Phys. Lett. B 811 (2020) 135849]

In the original paper [1], the relative distance ⃗𝑟∗ for p–p pairs composed of one primary and one secondary (i.e. coming from resonance decay) proton was not calculated correctly. Specifically, Eq. (5) in the original paper for the scenario in which one proton (proton 1) is primary and the other (proton 2) originates from a resonance decay should read ⃗ 𝑟∗ = ⃗𝑟∗ core + ⃗𝑠∗ res,2 , but it was implemented in the code used to extract the source core radius with a minus sign, namely ⃗𝑟∗ = ⃗𝑟∗ core − ⃗𝑠∗ res,2 . The mistake was not present in the code used for the p–Λ results. The error leads to a reduction of the final total source size which hence required eventually a larger source core size to describe the measured p–p correlations in the different 𝑚T ranges. In Fig. 1 we present the original (left panel) and the updated (right panel) values of the 𝑟core extracted from p–p correlations, compared with the published p–Λ results. The plot in the right panel of Fig. 1 replaces Fig. 5 in the original manuscript. The corrected numerical values are also available via HEPData [2]. The fitting procedure and the modelling of the resonances used for the updated results are the same as in the original paper, described respectively in Sec. 3 and Sec. 4 [1]. The net effect of the correction is a systematic shift, across all 𝑚T bins, of the 𝑟core value for the p–p system of ∼ 0.09 fm. Considering the statistical and systematic uncertainties, the number of standard deviations (𝑛𝜎) between the p–Λ (NLO13) and the corrected p–p results in the entire 𝑚T range is 𝑛𝜎 =1.9. This value was obtained using the NLO13 p–Λ interaction from Ref. [3] for direct comparison with the results in the original manuscript. However, more recent studies on the source and the p–Λ interaction [4,5] have shown that the NLO parameterization [1,3] overestimates the spin-averaged scattering length by 10–15%. This implies that the extracted 𝑟core for p–Λ (red points in Fig. 1) are biased towards larger radii. To address this, the p–Λ correlation functions in each 𝑚T bin have been re-fitted with an Usmani potential [6], fine-tuned to the eight best solutions listed in Table 1 of [5]. The best compatibility (𝑛𝜎 =0.90) between the p–p and p–Λ source sizes is achieved using point iv) from Table 1 in [5], which has scattering length (𝑓) in the singlet (𝑠) and triplet (𝑡) channel of 𝑓𝑠 = 2.50 fm and 𝑓𝑡 = 1.32 fm. The corresponding 𝑚T scaling (red points) is plotted in the right panel of Fig. 2 and compared to the p–p results (blue band). These findings confirm the original message of the paper about the observation of a common 𝑚𝑇 scaling of the 𝑟core for particle pairs in high-multiplicity pp collisions at center-of-mass energy √𝑠=13TeV.