Σ ⁺ production in pp collisions at √s=13 TeV

The measurement of Σ ⁺ Σ + production in pp collisions at √s=13 s = 13 TeV is presented. The measurement is performed at midrapidity in both minimum-bias and high-multiplicity pp collisions at √s =13 s = 13 TeV. The Σ ⁺ Σ + is reconstructed via its weak-decay topology in the decay channel Σ ⁺ → p + π ⁰ Σ + → p + π 0 with π ⁰ → γ + γ . π 0 → γ + γ . In a novel approach, the neutral pion is reconstructed by combining photons that convert in the detector material with photons measured in the calorimeters. The transverse-momentum (pT) ( p T ) distributions of the Σ ⁺ Σ + and its rapidity densities dN d N / dy d y in both event classes are reported. The pT p T spectrum in minimum-bias collisions is compared to QCD-inspired event generators. The ratio of Σ ⁺ Σ + to previously measured Λ Λ baryons is in good agreement with calculations from the Statistical Hadronization Model. The high efficiency and purity of the novel reconstruction method for Σ ⁺ Σ + presented here will enable future studies of the interaction of Σ ⁺