Measurement of the p$-\Sigma^+$ correlation function in pp collisions at $\sqrt{\textit{s}}=13$ TeV

Abstract

In this letter, the first measurement of the femtoscopic correlation of protons and $\Sigma^+$ hyperons is presented and used to study the p$-\Sigma^+$ interaction. The measurement is performed with the ALICE detector in high-multiplicity triggered pp collisions at $\sqrt{s} = 13$ TeV. The $\Sigma^+$ hyperons are reconstructed using a missing-mass approach in the decay channel to $\textrm{p} + \pi^0$ with $\pi^0\rightarrow\gamma\gamma$, while both $\Sigma^+$ and protons are identified using a machine learning approach. These techniques result in a high reconstruction efficiency and purity, which allows the measurement of the p$-\Sigma^+$ correlation function for the first time. Thanks to the high significance achieved in the p$-\Sigma^+$ correlation signal, it is possible to discriminate between the predictions of different models of the N$-\Sigma$ interaction and to accomplish a first determination of the p$-\Sigma^+$ scattering parameters.