The production of light (anti)nuclei in high-energy hadronic collisions can be described using statistical hadronization models or the coalescence of nucleons. The coalescence model is based on the hypothesis that (anti)nucleons that are close to each other in phase space can coalesce and form (anti)nuclei. The probability to form a nucleus with mass number A is quantified through the coalescence parameter BA, that combines the transverse momentum distributions of nuclei A and of protons. The model describes the ratio of the deuteron and helion (3He nuclei) yields to the proton yields as a function of multiplicity. This conclusion has recently been confirmed with improved accuracy using pp collisions at 13 TeV collected with a high-multiplicity trigger. The same data sample has been used for the precise estimation of the size of the emitting source via femtoscopy techniques. This measurement allows for the computation of theoretical predictions of the coalescence parameter for various scenario of the wave function of light nuclei. The figure shows that a Gaussian wave function describes the deuteron results (left) and overestimates the helion results (right). The comparison could be applied to more complex states like hypernuclei in the future.
The figure shows the measurement of the coalescence parameters B2 (left) and B3 (right) as a function of transverse momentum in high-multiplicity pp collisions and comparison with theoretical predictions corresponding to different nuclear wave functions.