Measurement of the p$-{\Sigma }^{+}$ correlation function in pp collisions at $\sqrt{\text{s}}=13$ 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 $\text{p}+{\pi }^0$ with ${\pi }^0\to \gamma \gamma$, 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.

24 pages, 4 captioned figures, 2 tables, authors from page 18, published version, figures at http://alice-publications.web.cern.ch/node/12778