Dergi makalesi Açık Erişim

Study of the Λ–Λ interaction with femtoscopy correlations in and p–Pb collisions at the LHC

2019    CERN İşbirliği

This work presents new constraints on the existence and the binding energy of a possible Λ–Λ bound state, the H-dibaryon, derived from Λ–Λ femtoscopic measurements by the ALICE collaboration. The results are obtained from a new measurement using the femtoscopy technique in Image 1 collisions at $\sqrt{s}=13$ TeV and $p\text{–}\mathrm{Pb}$ collisions at $\sqrt{{s}_{\mathrm{NN}}}=5.02$ TeV, combined with previously published results from Image 1 collisions at $\sqrt{s}=7$ TeV. The Λ–Λ scattering parameter space, spanned by the inverse scattering length ${f}_{0}^{-1}$ and the effective range ${d}_{0}$, is constrained by comparing the measured Λ–Λ correlation function with calculations obtained within the Lednický model. The data are compatible with hypernuclei results and lattice computations, both predicting a shallow attractive interaction, and permit to test different theoretical approaches describing the Λ–Λ interaction. The region in the $\left({f}_{0}^{-1},{d}_{0}\right)$ plane which would accommodate a Λ–Λ bound state is substantially restricted compared to previous studies. The binding energy of the possible Λ–Λ bound state is estimated within an effective-range expansion approach and is found to be ${B}_{\Lambda \Lambda }={3.2}_{-2.4}^{+1.6}{\text{(stat)}}_{-1.0}^{+1.8}\text{(syst)}$ MeV.