$\Sigma ^{+}$ production in pp collisions at $\sqrt{\textit{s}}=13$ TeV

The measurement of $$\Sigma ^{+}$$ Σ + production in pp collisions at $$\sqrt{s}=13$$ s = 13 TeV is presented. The measurement is performed at midrapidity in both minimum-bias and high-multiplicity pp collisions at $$\sqrt{s} =13$$ s = 13 TeV. The $$\Sigma ^{+}$$ Σ + is reconstructed via its weak-decay topology in the decay channel $$\Sigma ^{+} \rightarrow \mathrm{{p}} + \pi ^{0}$$ Σ + → p + π 0 with $$\pi ^{0} \rightarrow \gamma + \gamma .$$ 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 $$(p_{\textrm{T}})$$ ( p T ) distributions of the $$\Sigma ^{+}$$ Σ + and its rapidity densities $${\textrm{d}}N$$ d N / $${\textrm{d}}y$$ d y in both event classes are reported. The $$p_{\textrm{T}}$$ p T spectrum in minimum-bias collisions is compared to QCD-inspired event generators. The ratio of $$\Sigma ^{+}$$ Σ + to previously measured $$\Lambda $$ Λ baryons is in good agreement with calculations from the Statistical Hadronization Model. The high efficiency and purity of the novel reconstruction method for $$\Sigma ^{+}$$ Σ + presented here will enable future studies of the interaction of $$\Sigma ^{+}$$ Σ + with protons in the context of femtoscopic measurements, which could be crucial for understanding the equation of state of neutron stars.